Toyota Prius Inverters and Converters

Hello, I'm professor John Kelly and this is the  WeberAuto YouTube channel. In this episode we   are going to look at the components parts and  operation of inverters and converters in hybrid   vehicles the inverters and converters in electric  vehicles are very similar and we will take a look   at those in later episodes but for now let's take  a look at the inverter converter assembly in this   2010 Toyota Prius that we've used in previous  videos I shot a previous video on a low voltage   system on a Toyota Prius and you can see that  clicking on this link and I shot a previous   video on the high voltage system where we looked  at the high voltage nickel-metal hydride battery   in the same series of vehicles the Priuses and  you can see that by clicking on this link in   those previous videos we looked at the battery  location and how the battery works what it does   we looked at the 16-foot long cable that goes  from the battery up here to the inverter with   converter and today we are going to learn how to  safely test to see if we can disconnect that and   get this inverter converter assembly out and  take a look at it so the first step before we   can disconnect any cables up here and remove  the inverter with converter is to de-power   the high voltage system on the vehicle now if  the system is working properly with the power   button off on the vehicle or the key off on  whatever vehicle you're working on it should   be de-powered anyway but you always must verify  and you should be using your personal protective   equipment high voltage gloves and whatever else  is necessary for what you will be doing on   that particular vehicle and I have a separate  video on personal protective equipment that you   can see by clicking on this link so the first step  is to make sure the car is deep powered turn the   turn the key off hit the power button shut it off  get the key fob out of the the vehicle there's the   key fob I'm just going to set it over here on  the bench get it out of the way all right now   that we have the power turned off and the key  fob out of the vehicle we need to disconnect   the low-voltage battery wherever that is on the  vehicle on this particular vehicle it's in the   trunk area so let's disconnect the negative cable  okay here we are in the trunk area and right here   under this cover is our low voltage battery and  our negative cable is just right there so we'll   come in and just loosen up loosen up that  nut and take the negative battery cable off   of the battery and then while we're back here  right here on the high voltage battery we will   reach over and pull over on the service plug  grip rock it back and then pull straight out   so we've got that removed which d powers the  battery internally okay with our service plug   grip removed now we can come to the top of the  inverter with converter assembly and right on   the top of this assembly is this black cover right  here there are nine bolts holding this black cover   down we have to remove that cover before we can  access the electrical connections to disconnect   the high-voltage battery the two wires from the  high-voltage battery that we looked at in the   previous episode of on high voltage this cover  also has one of those high voltage interlock   connectors on it okay we've got all the bolts  out of the cover if we lift up on the cover here you can see the high voltage interlock connector  is just two terminals that plug in over here on   the side that completes the interlock circuit  when it's plugged in but when we remove it it's   opened and if the system were still powered up  somehow even though we've got the 12-volt battery   disconnected the service plug grip removed if  for some reason at state powered up the interlock   circuit should notify the high voltage ECU the  computer in charge of the high voltage system to   open the contactors and remove the voltage from  the two wires that come up here to the inverted   converter in the last episode on high voltage  hybrid and electric vehicle systems we looked   at the hybrid battery junction block that's in  side of the battery case in the back of this   vehicle and we saw that there was a negative and  a positive contactor in a pre-charge contactor   and a pre-charge resistor and I commented that  the difference between a contactor and a relay   is that a relay just opens and closes one set  of contacts where a contactor opens and closes   two sets of contacts at the same time and I've  had some people comment that they weren't sure   that was true and so I took the cover off of  the negative contactor and I want to show you what   it looks like inside here so what you're looking  at there are the two ends the two contactor ends   inside of this ceramic housing right here are the  two contactors that we talked about that make and   break connection with these two terminal ends that  stick out the bottom of the contactor and plug in   to the hybrid battery junction block I want you  to see on the coil side of things that it has   both a pull in coil and a hold in coil much like  a starter solenoid which is also a contactor and   it's all hermetically sealed it keeps oxygen and  moisture away from those contacts so they should   last a long time but that is a contactor with two  contacts being open and closed at the same   time where if you've ever looked inside a relay  it's just one set of contacts opening and closing   okay so when you disconnect this high-voltage  interlock circuit it is supposed to open all of   the contactors let's say you forgot to disconnect  the 12-volt battery and you pull that cover off   the contactors should go open immediately if  they were already if they were closed but they   shouldn't be closed with the power off on the  vehicle but maybe you've got a contactor that's   stuck and so you always need as I said before  your personal protective equipment and then the   very next step is to check to make sure that you  can take off your high voltage gloves and just   use regular tools and bare skin on the rest of the  inverter converter removal and the way you do that   is you take a multimeter so I've got my Fluke 87  multimeter here which is a category-III meter   which category-III is rated for  three-phase high voltage circuits up to 1,000   volts on industrial equipment and we are going to  go in and on the two wires coming from the battery   where they go into the inverter converter we are  going to just measure their voltage now remember   it's a 201.6 volt battery back and  if the contactors were open we would read or we   should read zero and we are reading zero volts  DC it's a DC battery now if those contactors   were both closed the negative contactor for  the negative cable the positive contactor for   the positive cable so they would both have to  be closed at exactly the same time for us to   get any voltage here so there's no voltage there  that means the contactors are open but let's just   make sure we don't have any connection to ground  of the chassis anywhere so we'll just go to the   case of the chassis and we still get zero volts  there and so that was on one of the two wires   from the battery so now I'll go back to the other  terminal and go to the case on the other one and   we are still at 0 volts so that means there is  no voltage there's no power on either of those   two wires so we also have two other electrical  connectors with orange wiring on them they have   three wires per connector those are three-phase  AC not DC these are AC voltage wires and they will   only have voltage on them and be able to provide  current if the engine is running or about to start running   the middle connector here is for MG1 in the P410  transaxle that is what starts the engine and what   acts as a generator to charge the high-voltage  battery as you just sit here idling or as you   drive down the road the end connector here is for  MG2 which is the traction motor in this transaxle   that moves the vehicle down the road either  by itself or with the assistance of the internal   combustion engine through the power split device  so these are AC voltages the engine is off there   should be no power on any of those just to be safe  let's check it all I had somebody comment   in a previous video on high voltage that the meter  leads I was using that had the long tips no longer   met the category three requirements under the IEC  the International electoral Technical Committee   standards and they needed to be these short little  tips here for a category 3 up to 1000 volt 3-phase   AC and I looked that up and he was absolutely  right the older meter leads that say category-III   on them, they did meet the cat-III specs back on a  previous standard but the newer standard requires   these shorter tips which provide more safety  there's less area there for flash overarching of   accidental finger touches and so on so we're just  going to check on DC we'll go from each terminal   to terminal 0 0 0 each terminal to the case 0 0  0 same thing on the other two outsides together   inside to outside inside to outside outside  the case middle of the case outside the case   they're all 0 so there is no dangerous voltage  on these terminals and we can now unscrew them   and disconnect the wires from the  inverter converter also on the disconnecting the   inverter converter there are seven wire harnesses  that connect this thing we've got the battery the   high voltage battery we've got the two connectors  for the electric motors we've got the DC output   power we have a connection to the HV ECU a  connection to the trans axle and then two   coolant hose connections one of them goes from  the driver's side of the inverter converter up   to the coolant reservoir for the electronics the  other one goes down to the transmission and the   path is from the reservoir to the inverter to  the transmission down to the dedicated section   of cooling in the radiator and then back to  the coolant reservoir alright well let's go   over to the bench where I already have one of  these removed and along with a bunch of other   inverters with converters on some and we'll look  at the original converter with inverter from the   2001 through 2003 Prius here in the United  States I told you in the very first episode   in this series that I thought the original  1998 Toyota Prius from Japan is what everybody   else has based their hybrid vehicle design and  platform on and by looking at and understanding   that original Prius which we have a 2002 here in  the shop so 2001 through 2003 were the first here   in the United States we will look at the original  inverter converter there and then we'll look at   the other inverter converters and you'll see that  they all have the same parts they're not made by   the same people they're not made to handle the  same amount of power they look different but   what they do is exactly the same so if you can  understand that one then you can understand the   rest of them alright well let's go over to the  workbenches okay here on the bench I have seven   different inverter converter assemblies the only  one I didn't get out that I do have is a Honda one   and we'll look at that in a different episode  on Honda hybrid vehicles but let's start with   here on the end of the table these two parts  right here are the first generation Chevrolet   Volt so 2011 through 2015 Chevrolet Volt what I  have here is an inverter assembly only without the   DC to DC converter so if you recall the DC to DC  converter is basically the charging system for   the low voltage system on a hybrid or in electric  vehicles so the inverter its job is to drive the   electric motor or motors in the transmission or  if it's sandwiched in between the engine and the   regular transmission or whatever it may be it will  have some sort of a electric motor that the   inverter drives so this is the 2013 Chevrolet Volt  inverter and at the Volt transaxle the 4ET50 has   two electric motors motor A and motor B and we  will look at those in a episode on Chevrolet but   it has in the back of the vehicle a separate DC  to DC converter which by the way the in the back   of the vehicle is the 12-volt battery for the low  voltage system on the bolt and so it's just right   there next to it the battery is so big underneath  the Chevy Volt that they can connect just right   there at the battery to run the DC to DC converter  okay the next inverter I have here is a 2013   through 2016 ford fusion hybrid inverter only just  like the Chevrolet Volt inverter only no DC to DC   converter on the Ford the DC to DC converter  is built into the 1.4 kWh battery   assembly in the trunk and it is a serviceable  component you can replace that just like on the   Chevy Volt one you can replace the entire assembly  but Chevrolet does not allow any internal repairs   into the inverter or the DC to DC converter  Ford does not allow any internal repairs and as   a matter of fact Ford doesn't even call it  an inverter they call it the transmission control   module which at first I thought why did they do that  because everybody else calls it an inverter then I   thought well it does control the transmission  the HF35, two electric motor, transmission so I   guess that that is what it does but searching  all through Ford service information trying to   find information on it an inverter and it I  couldn't find it and eventually, I finally found   a link that had the word inverter in it but it led  me to the transmission control module and I looked   at a picture of it online and sure enough that  so Ford's inverter assembly is the transmission   control module these two cables right here are  what drive the two electric motors in the hf 35   transaxle alright now the next inverter and this  is an inverter with a DC to DC converter this one   is out of our 2017 Toyota Prius that we just  bought earlier this year here at Weber State   automotive and this has the inverter assembly  in the top and down underneath is the DC to   DC converter and this is a fully serviceable  inverter converter assembly you can buy the   intelligent power module the circuit board that's  in the top of this that interfaces with the high   voltage ECU to drive the IGBTs the big trend power  transistors that run the two electric motors the   mg 1 and mg 2 and then you can also replace the  DC to DC converter in the bottom of this and you   can buy the in-between piece so really there's  only three serviceable pieces here the DC to   DC converter the intelligent power module and  then the rest of the assembly that contains   the boost inverter and the IGBTs and the coolant  passages and so on all of these that we've looked   at so far the Chevy Volt as you can see right  here there's two coolant hose fittings the ford   fusion two coolant hose fittings the 2017 Toyota  Prius eco the one with the lithium-ion battery two   coolant hose fittings these are all liquid-cooled  inverters they run really hot they have their own   dedicated coolant system the DC to DC converters  that are in the back of the vehicle those are just   air-cooled okay so that's fourth-generation Toyota  Prius then the next two inverters these two here   they look like twins these are third-generation  Toyota Prius but if you look closely this one's   called a Type B inverter and that one inverter  converter assembly and that one's the type A if   you notice on the type A over there it has a label  right here that this one does not and on a type B   this one has the label right here that that one  does not but they also have a coolant hose on   each side for keeping it cool so in the bottom of  this we have the DC to DC converter and the boost   converter module and there the big reactor coil  in there that's used to bump the voltage up higher   than what battery voltage is inside of this we've  got the IGBT module that can be replaced with the   coolant passages we've got the intelligent power  module the computer that's in charge of that and   some internal circuitry that can also be replaced  and then if we go down a little bit farther this   this one right here is second generation Toyota  Prius it also is liquid cooled and it has pretty   much the same serviceable internal parts that  the third-generation Prius inverter converter   does except it breaks up some of those parts into  smaller individual pieces rather than combining   them and then if we go all the way back to the  first-generation Prius that inverter with DC to DC   converter Mazda right there has the same there has  the same function but it breaks up some of those   parts that were in the second generation one into  even more individual pieces okay there's one more   thing I want to show you before we look at the  internal parts and components of these inverters   and that is the common electrical connections  that they have so starting here with this old   original Toyota Prius inverter converter assembly  these two wires right here these two are the high   voltage battery connection from the trunk we've  got the positive cable and the negative cable   then these three wires right here that are cut  off obviously powered the motor-generator number   two that propelled the vehicle and then these  three wires right here that make an electrical   connection up underneath here with this connector  power MG1 the starter and generator portion of   the inverter converter and then we have all  these electrical connections right here all   of these connect to the high-voltage ECU so over  here underneath the high-voltage cables we have   the low voltage cable this is the positive cable  coming out of the DC to DC converter fourteen and   a half volts 100 amp output but that's just the  positive side we need a negative side also so this   cable over here that every one of these inverter  converters have just for the low-voltage system   that cable has nothing to do with the high-voltage  system provides the ground that connects to the   negative battery terminal at the back of the  vehicle through the vehicle body and then we   have an electrical connector to control the DC  to DC converter right there by the way these   original first two generations of Priuses also  had an airbag discriminating sensor one of the   two sensors required to set an airbag off these  are mechanical sensors it took a discriminating   sensor one of the two in the front and an arming  sensor which was in the passenger compartment to   close at the same time to set the airbag off there  is a vent right here that allowed air to go in   and out of the inverted converter assembly as it  heated up on the second generation Prius almost   identical we've got a single wire harness coming  out now rather than these large four electrical   connectors that connects to the high voltage ECU  we still have the airbag discriminating sensor we   have the negative and positive cables that connect  to the high-voltage battery in the trunk we have   the three-phase cables that connect to mg2 and in  the front of this we have the three-phase cables   that connect to mg1 we have our 12 or 14 and  a half volt output from our DC to DC converter   right here we have our inverter can control wiring  that hooks to a computer and then right here this   second-generation Prius was the first one to have  an electric air-conditioning compressor so we have   control wires for the AC compressor controls and  all of that is built into the DC to DC converter   so in the front up here that orange cable those  three orange wires right there in that orange   connection that goes to the air conditioning  compressor that's bolted to the engine but there   is no fan belt connected to it all right here we  have the third-generation Prius we have the two   wires coming in from the high-voltage battery we  have three wires going out for MG1 for MG2   we have our DC low-voltage 14.5 volt  output right here just the same as the previous   ones but obviously everything is smaller and then  on the third or fourth generation Prius we have   our two wires coming in from our high voltage  battery in the trunk this connector here is for   the electric air conditioning compressor this is  the wire harness right here for that that will   just plug right in and be bolted down at that  point there's an electrical connection right here   that connects to the high voltage ECU and then on  the side here there's one great big opening that   connects to the mg one and mg 2 electric motors  and there's also a high voltage interlock in   there to disconnect the system all of these have  the interlock there's the interlock under this   cover right here on the 3rd generation there's an  interlock under this cover and under this cover   right here high voltage analog circuit so all of  them as you disconnect the high voltage DC cables   have an interlock some wire that disconnects them  alright let's look at the Ford Fusion inverter   we've got the two wires two sets of three wires  going out to power the two motors in the HF35   transaxle there's an electrical connection  right here for the DC high-voltage battery and   the AC compressor I believe is this nope it's  in the front I believe alright and then here   on the Chevrolet Volt, we have DC on this cable  here from the high voltage battery and then we   have an output to the air conditioning compressor  right there and right here on the side to three   wire connections to run the two electric motors  inside the 4ET50 transaxle and then we have our   electrical connection here to an external computer  that controls the inverter we've got a connection   right here on the first-generation Prius and the  second-generation Prius we have some bleed screws   for the coolant system so this one has two screws  right here this one has a hose that connects to   the transaxle and it lets you bleed the air out of  the cooling passages in the transaxle this one has   a hose that just comes over here to the coolant  pipe for the inverter converter assembly and let   you bleed the air out of that and then the second  generation one just has a single bleed screw just   for the transaxle they got rid of the one for the  inverter converter assembly so let's take a look   at the original Toyota Prius inverter converter  assembly and then I'll explain how all of these   other inverter converters have combined some of  those original parts and just made them smaller   but doing the same function okay we've got the  2001 through 2003 Toyota Prius inverter with   converter converters in the bottom inverter  assemblies in the top inverter takes DC power   inverts it makes three-phase AC power in this  instance there are inverters that you can put   in your car that take your 12, 12 to 15 volt DC and  inverted into a single-phase 120-volt power supply   for you to plug something in your in your  vehicle for removing this from the vehicle as   I've already shown on the 2010 Prius we just need  to make sure that we pull the service plug grip   and make sure that there are is no power from the  battery to the inverter converter assembly now on   the back of the inverter converter assembly here  we have two big electrical connectors for the high   voltage battery so I'm going to disconnect the DC  voltage connection there's a plastic tab I have to   push down on and pull back I'm not quite strong  enough to pull back so I'll give it a little pry   there and here we go it's a shielded DC cable  this first-generation one is the only one that   has a shielded DC cable if you look closely at the  the wire end there you can see the shield around   it so that's the positive cable or that was the  negative one and here is the positive one get that   out of the way then down below over here I've got  the 12-volt connection for the DC to DC converter   it's our 100 amp 14.5 volt output we have  the electrical connection for the controller for   the DC to DC converter that connects to the  high-voltage ECU then here on the driver's   side we have the discriminating airbag sensor we  pull back on the little yellow plunger and unplug   it and then we have for electrical connections  that connect the inverter converter assembly to   the hive GCU and these are all connections that  are part of the monitoring the voltage levels   on the output on the three-phase cables and  controlling and watching the voltage levels   on the insulated gate bipolar transistors these  plastic electrical connectors are pretty the the   pretty brittle the older they get so be careful as  you are unplugging them that you don't break them these are weather-sealed electrical connections  which means the they're meant to keep water   that splashes on them from intruding into the  electrical electrical connector but they are not   made to be sprayed with a high-pressure carwash  so don't spray electrical connectors directly all   right we've got all of the electrical connectors  disconnected and we've got the two coolant hoses   one here at the reservoir and one down front there  that hooks to the transmission the transaxle so we   would want to drain the coolant out of the vehicle  also not the engine but the electronics coolant   which has a separate drain separate portion of the  the radiator on the big heavy three-phase cables   that go from the inverter converter assembly down  to the transaxle on this connector right here for   mg1 we have to undo the two bolts that go all the  way down and connect to the connector itself and   that disconnects of course the discriminating  sensor of the air bag so we'll set that   off to the side there's a lid right here but as  we lift that up it disconnects a high voltage   interlock circuit right there that should open  circuit the contactors if somebody forgot to   turn the key off or if there was a problem  with the vehicle electrical system somehow   they were stuck on a bad contactor and then  we've got these three bolts right here that   go through here that we have removed the bolts  and pull that cable down and out of the way okay on the back of the inverter converter  assembly here we have four number thirty Torx   head bolts that we've got to take out to get to  the three face cables that feed motor-generator   number two the one that propels the vehicle down  the road so we get those four bolts out and lift   up the cover this cover as we lift it up also  has a high voltage interlock circuit on it so if   somebody took this off and didn't know what they  were doing they weren't proper trained it should   open circuit the contactors that we talked about  and disconnect the DC power from the inverter   converter assembly and when you disconnect the  inverter converter assembly from the high-voltage   battery they tell us that you should wait so many  minutes to allow a big capacitor in here it's   called a smoothing capacitor that smooths out the  rippling voltage from the generating portion of   MG1 and MG2 - there's a resistor across that big  capacitor that will slowly discharge the capacitor   but it'll take a certain amount of time to be able  to discharge that I haven't seen a time that was   any longer than 10 minutes though next we have  three bolts that make the electrical connection   from the three-phase cables to the bus bars in  the inverter converter assembly and so we'll take   those out and then there are three ten millimeter  head bolts that hold the cables to the inverter   converter assembly housing these cables are  individual cables they're not all hooked together   like they are on later model Priuses I like to use  ziplock bags to keep everything organized when I   take something apart also the very first time I  take something apart I take a lot of photographs   and I'm talking a lot like every time I take a  pee piece off of a transmission or an inverter   converter or whatever I'm disassembling I might  take a photograph at that point just to see   what it looked like before and after because  sometimes there are no good instructions in the   service information and sometimes there there  are but there's nothing like documenting how it   actually was when you took it apart so I've just  taken out what's called the U phase cable there's   a W, a V, and a U phase of the three phases and  so that cable is disconnected this would go down   to the transaxle but it's been cut off because  I purchased this from a salvage yard so here's   the V cable and the W cable salvage yard just  cut all the cables and sent it to me which I   wish they would have disconnected them but then  we run the risk of internal contamination when   you have somebody else unbolting all of this  stuff and you could possibly get water in there   the Ford Fusion inverter can our inverter I have  down there was clear full of water when I got it   and you could see where it had corroded a lot of  the parts and it was totally unusable it works   good for a demonstration for my students but  it wasn't certainly wouldn't be a useable part   all right so we've got all of the electrical  connections disconnected and now we are ready   to take off the cover of the inverted converter  assembly now sitting right here this red mat is   is an anti-static mat and that anti-static mat has  a ground wire that you just with an alligator clip   you clip it to your workbench I've got a clip to  a metal leg of this table just something that has   a lower voltage potential than you then your body  has and then it has a wrist strap here also that   will ground your body to that same wrist strap and  that will or to that same ground and that should   protect the electronic the sensitive electronic  components inside the inverter converter assembly   from electrostatic discharge from your body so now  we've got as we're taking this off it has a bunch   of 8mm head bolts I'm going to use an  electric impact but I'm going to not just go full   throttle and rip threads out of everything I'm  going to break it loose and slowly back them out steel bolts in an aluminum housing if you give  it full throttle on your impact electric or   air-powered you are asking to rip some threads  out with it all right now we'll lift up did I   miss another one for yes that's what I get for  doing it behind here we go now we're gonna   lift up carefully oh one thing before you  take any covers off I forgot to mention this   everything needs to be clean you need to get  the dirt the dust leaves whatever office and   try to prevent the best you can any of that from  getting down inside the inverter converter   assembly especially if you're working on it in  the vehicle if you're working on it externally   like this and you're going to take the whole  thing apart anyway like I am you can clean it   afterwards but if you drop anything down in  there they recommend that you get some tape   like this blue masking tape here and use  the sticky side to try to pick up whatever   particles happen to have fallen down in so as  we lift this up we want to make sure that we   don't get a bunch of garbage down inside of the  inverter converter assembly so here's our lid and the bolts that go with it all right let's  look at a few parts while we are here we have   three great big smoothing capacitors and here's  that resistor I told you about that will drain   all of these are bolted in parallel with each  other so if you discharge one it's discharging   all of them with this DC busbar ground or  DC busbar that's there we have the signal   processor slash protective function process or  the circuit board right here the interfaces with   the high voltage electronic or high voltage yeah  the high voltage ECU the electronic control unit   so this wire harness comes in and plugs in right  here on this gray electrical connector the next   thing that we have we have two orange connectors  under here and of course orange means high voltage   but we've already disconnected the high voltage  battery we've waited the proper amount of time   to let the capacitors discharge it would be  a smart idea to grab a multimeter and put   across the capacitors before you touch them with  your fingers just to make sure that they're that   they are discharged okay I'm on DC volts I'm  just going to come in and measure across I've   got zero volts and so it's safe to touch those  capacitors all right I'll get my ground strap   back on here okay our next step is to disconnect  all of these electrical connectors they all have   a little tab on them these orange high-voltage  ones are underneath come on there we go so this one is 4mg two's voltage circuits this  one is 4 mg ones volleyed circuits there are   two current sensors in the inverter converter  assembly we have a MG2 current sensor which   measures how many amps of current are being fed  to the MG2 motor and then we have another one   over under this plate here for MG1 so we have MG2s current monitoring circuit right here an MG1's current monitoring circuit right there  and then we have MG1's transistor the hype   the hype our transistor controls the IGBTs  control circuit right here an MG2 control   circuit right here and then the interface  with the high voltage ECU that is under the   dash on these Priuses right there alright  so we've got all the electrical connectors   disconnected except for this eyelet right here  and now we will come in not with an impact gun   but just a non insulated we don't need special  personal protective tools on this system because   it has no voltage I've only just nothing's  dangerous on here at this point so we are   going to unbolt the circuit board wearing  this ground strap so we don't damage it and get it out of the way all right  I believe that's it let's lift up   oh we've got a connector or a plastic  tank connector right here we have to   squeeze the little locks on the other side  squeeze the locks pull that out and now we   are ready to lift up always try to avoid  touching the circuit board or any of the   electrical connectors the pins themselves  don't touch any of that stuff especially   if you don't have a ground strap on so we are  going to set that just right over here on the electrostatic discharge mat and then the  next thing we are going to take off is   this big pack of capacitors okay bolts  out of the plate that it's in but there   are six electrical connections to a bus bar  right here that connects if we follow let me   get these wires out of the way here's our DC  negative and positive posts right here from   the high-voltage battery notice those wires  come right in and connect directly to the   bus bar that the capacitors are connected  to so we've got to disconnect not only the high-voltage electrical connection from  the battery but we've got to disconnect   the capacitors from that so there's a nut for  the negative cable not for the positive cable there's four bolts that hold this electrical  connection to the case give us ziploc bag for the   connector and it the bolts this orange electrical  connector if we lift up on the two wires from the   battery it doesn't just fall out because it's got  the shield ground connections right there remember   the two cables coming in we're shielded so it's  got kind of a crimp or spring-loaded fitting there   so now we'll sit those off to the side now we can  undo the six bolts that hold the capacitors to   the busbar okay now I believe we can just lift up  on the capacitor assembly get it out of the way I   think I'll put those capacitor bolts in here with  the high voltage DC connection alright next thing   this DC bus bar right here that was fed by  the DC battery in the trunk needs to be   disconnected so it connects to two modules here  we've got this great big module that has the IGBT   intelligent power module for MG2 the electric  motor in the transaxle that propels the vehicle   down the road this is other modules for MG1 the  the starter flash generator so they both need a   DC connection with the power and a ground so we  have two wires coming in and then three wires   going out on both of these modules so the two big  bolts I'm taking out now are the ones that feed   power voltage and current to the IGBT module  that runs MG2 and the two little ones next are   the ones for the module that drives them MG1 the  starter generator okay now right here we have two   other fairly heavy wires they're not as big as  the DC cables coming in from that high voltage   battery but these two wires right here these are  where the DC to DC converter underneath this whole   assembly picks up its power from the IGBTs or  an the high voltage battery in in the back of   the vehicle so now we can just lift up on this bus  bar this big heavy looks like it's nickel coated   to avoid corrosion busbar and we'll put that in  its own zip lock keep it all separated okay now   we have several wire harnesses remember all these  connectors here that we disconnected they got to   connect somewhere on the other side so this  orange high voltage cable for monitoring the   high voltages comes clear over here for the MG1  module the current I'm sorry the driver control   circuits for MG1 are over there and then we also  have another clip here the current sensor for MG1   and then one more connection right here this is  actually the high voltage interlock circuit for   MG1 electrical cover when we took that cover off  right here these two pins opened up this circuit   that also comes over to the high voltage interlock  circuit for MG2 so if either one of them opens up   then it will it'll kill the high voltage battery  it will open the yellow by opening the contactors   okay so we've got that disconnected so we've  got the current monitor right here for MG1 so   now we can come in and disconnect the three-phase  cables three-phase busbars that feed MG2 and MG1   let's do MG2 first we'll disconnect the 3 heavy  or bigger bolts they're 12 millimeter head bolts   at 12 so get those out of the way and then they  come over here and bolt down to the electrical   connector where the three-phase cables come in for  MG2 so we'll get those out of the way and then we   also have MG2 current sensor right here let's  get it out of the way hit the same same time just lift that up pull the wire out with it  so we're going to bag mg - current sensor the   bolts for the busbar the high voltage interlock  circuit and now we can rock out the busbar for   the three-phase cables for mg - and we'll keep  that here in the same bag alright now we'll do   the same thing over here for MG1 it has its own  bus bars right here so we've got 6 bolts holding   the bus bar that connects the wire harness  forMG1 to the IGBT module for MG1 the IV's   IGBT modules they are they have a full-wave  rectifier bridge with 6 diodes just like an   alternator does on any other non-hybrid vehicle  so a rectifier bridge takes the AC voltage and   inverts the negative phase makes it a positive  phase and then we use the big capacitors to   help smooth that out alright here is the  three-phase bus bar for MG1 and it's bolts and now we can take the electrical  connector that goes with MG1 and   remove it and get it in its current sensor  out of the way okay so at the interlock   circuit wire and the current sensor  wire right here for the MG1 electrical   connection and now I can show you how  that would go up in and bolt together all right so we'll keep all that in the same bag  here and then the last part to take out of there   is the current sensor for MG1 lift that and it's  harness that went up to that processor board bag   all that up is one big piece alright just about  got the upper portion disassembled we've got a   couple of we've got a junction block right  here with the two studs for the high voltage   battery connection to three things the DC to  DC converter down below the bus bar that feeds   DC to both the IGBT module for MG2 and the one  for your MG1 now we've got the wire harness on   the side of the housing here it's got a couple  of bolts that hold that in place it looks like   they're captured bolts so they don't come out  all the way they'll stick with the harness and   then there's a rubber grommet that holds that in  place there we go now we can rock out there we go okay so there's our complete harness or  interface harness between the internal   circuit board and the external high-voltage EC  you set that off to the side and now the only   things left inside of the upper housing here  are the two IGBT modules so let's get those   out these have a 5mm hex head bolt that holds  them on these modules are what tend to go bad   over time on these inverter converters there's  a couple of reasons they can go bad one the   heat sink compound the thermal transfer grease  whatever you want to call it seems to lose its ability to transfer heat over time and then some  out of the factory didn't have the grease spread   evenly and so there was not an even heat transfer  that took place and that would kill some of the   IGBT modules and not just this model year but  the future for later model years different well   clear up through the third-generation Prius these  it's one of the reasons they're all serviceable   as there have been service campaigns to go in  and replace some of these parts it takes a very   special thermal transfer heat transfer grease to  do the job I don't know of an equivalent in the   aftermarket world the only place I'm aware  of where you can get this stuff is from   Toyota themselves okay so I've got all the bolts  removed up now to remove these IGBT modules they   are going to have kind of with that thermal  transfer grease they're going to have kind   of a vacuum-sealed to stick to the heatsink  that this coolant goes through to remove the   heat from the IGBT modules and it helps if  you can slide it sideways just a little bit   and then find a corner that you can lift up on  and get that module out and then it looks like   I've I should have just taken the bolts all  the way out no I missed one no wonder okay all right now I have previously taken this  inverter converter assembly apart and purposely   cleaned off the heat transfer grease because  it's such a mess for demonstration purposes   but right here on these three metal tabs  here it would be coated with this was a   white-colored thermal transfer grease there's  a gray-colored one that's used in some later   models and this flat surface here with  the heat transfer grease fits right down   flat on this aluminum surface here that I  have labeled as the MG2 intelligent power   module heatsink and right under this as  we'll see here in a few minutes are the   cooling passages that the liquid coolant goes  through so I'm going to set that over here   on the anti-static mat and then we'll take  out we'll do the same thing with MG1s IGBT we've got two heat sinks there and a big heat  sink in the aluminum housing here to transfer   the heat out of the module into the housing into  the coolant up to the radiator and then into the   air is the cooling process there all right  so we've got the upper portion all stripped   out and got it on the side here is the coolant  reservoir and we need to take that off next to   turn this inverter converter assembly upside  down and take off that the converter so it   just has I think four bolts that hold it  in place for both two bolts and two nuts you want to make sure that you don't get  any coolant on the electronics make sure   everything's pre drained before you do  anything so this coolant reservoir here   has an o-ring right here that seals  to a passage on the side of the case   for coolant transfer into the coolant  passages underneath the heatsink here just bag that up keep everything organized all  right we could on both this extension housing   here but there's really no point in doing so  so now let's turn this whole assembly upside   down remember the only thing left in here are  the two wires the DC high-voltage wires that   go to the converter assembly where we take the  273.6 volts and step it down through the center   tap transformer and output 14 and a half volts so  let's turn this over. all right I'm going to take   out very slowly the bolts that hold the DC to DC  converter to the bottom of the inverter housing normally this is sealed with a special black form  in place gasket sealer from Toyota and it's it's   a very good sealer and glue which means you're  not going to just be able to lift this up there   are price these little tabs here where you can  pry up slowly don't go over really quick on it   you got to pry up real slow and let that sealant  break loose because it breaks loose real slow if   you have patience at work if you force it, it'll  break the pride tabs off at the bottom here so   I've already taken this one off and so let's take  this out and look at it so here on the bottom of   the dc-to-dc converter we've got kind of a flat  plate but you can see some guide lines there for   the coolant and then the dc-to-dc converter is  under this cover right here this whole thing   is just serviced as one assembly so you can  buy the DC to DC converter so if your 12-volt   battery keeps going dead and you do the voltage  check with the vehicle powered on and you're not   getting 14 volts 14 to 15 volts at the battery the  low-voltage battery and you don't have any other   trouble codes chances are really high that your DC  to DC converter is bad and you can buy a DC to DC   converter and install it it's a lot of work  but it can be done alright the rest of what   we're seeing here are the coolant passages let's  see the coolant would come in right here from the   reservoir and then just make this serpentine looks  like it makes 1 2 3 4 5 6 7 turns and then at and   it's absorbing heat from these IGBT modules that  are on top of it and then it goes to the transaxle   to cool it before it goes to the radiator so  that's been a lot to disassemble but I told you   if you could understand this inverter converter  assembly then you would be able to understand the   rest of the six inverter converter assemblies that  that have got on the table here so all of them are   going to have some sort of a power transistor  module for each electric motor that needs to be   driven all they did on the second-generation Prius  is they took these two modules the IGBT modules   for the two electric motors combined them into  one big module and then took this circuit board   right here and put it on top of that so that  is one assembly these three pieces now have been   combined into one on the later generation modules  these three capacitors right here are now combined   into one big capacitor and there there are other  capacitors I mean this board has capacitors on it   also but there are other capacitors that are used  for other things in driving the electric motors   and receiving power from them during regenerative  braking when you slow down but they've combined   the resistor and the capacitors into this one  great big module and we'll we'll look at that   here in just a few minutes we're not going to  totally disassemble the next one but the next one   actually has two additional pieces in it that this  one did not have that all of the other ones do   have to my knowledge and that is called the boost  converter and reactor and as I tried to explain   before on the first generation Prius they used  a higher voltage battery to drive the to drive   the transmission on the second and subsequent  generation Priuses in Fords they went with a lower   voltage battery but then inside the inverter  converter assembly they bump up the voltage   through self-induction on this great big reactor  coil and add another up to 300 or more volts   depending on what model year and vehicle it is to  on top of the voltage that the battery supplies so   a 201 volt battery now can put out five or this  with the in the boost inverter can now put out   500 volts which gives the transaxle more power  gives the vehicle more power because the very   first generation ones were a little underpowered a  lot of customer complaints about that okay so that   is the first generation Prius here in the in the  United States inverter converter module you can   buy as I said the DC to DC converter but they  to my knowledge they don't sell these internal   parts anymore you got to buy the entire inverter  converter assembly if you need any of these parts   or you can attempt to find something off of  eBay but just beware there's a lot of garbage   out there I bought one of these off of eBay and  I opened it up and the salvage yard I bought it   from had taken a green paint marker and put their  initials all over everything inside and outside of   this inverter module inverter converter module and  they actually drew on the circuit board with this   paint and I suspect that it's conductive paint  which would totally ruin it it's a good thing   I only bought it for demonstration purposes that  lookout there's there's a lot garbage for sale out   there also and you won't know about it until you  get it alright let's look at the next generation   inverter converter but only as far as seen what  is different between it and this one and then that   will finish up our discussion on inverters because  they're all basically the same after that okay   here we have the second-generation Prius which is  2004 through 2009 inverter with converter assembly   so let's look at what's different on this thing  alright same type of coolant reservoir except   it has a little nipple that sticks inside  of the housing rather than sitting flush like the first-generation one did all of the bolts  on the cover except this front one right here just   have a 10 10 millimeter head that front one is  a number 30 Torx for whatever reason probably   to keep most people that don't even have a Torx  from taking the cover off it's the only thing I   can think of keeping the curious-minded  people out and miss another bolt yep all right if we lift up on the cover on the  backside of the cover or I'm sorry on the front   side of the cover right here we have the high  voltage interlock circuit so as you lift off   the cover if you were untrained and had no idea  what you were doing and the key was still on the   contactors wouldn't your shield should go open  at that point all right now the next thing   to remove is the wire harness right here the  external interface with the high-voltage ECU   and it just lifts up and out this would be part  of the main vehicle wire harness under the hood   and just sit right there are there's the  positive post and the negative post just like   we had over there where our high-voltage wires  are going to come in and so we can take those   off never ever use an impact on anything that is  connected to plastic so these studs are embedded   in a plastic piece that's part of the capacitor  assembly so this big capacitor this big black   block right here replaces all three of those  round capacitors on the first generation Prius now we can undo our high-voltage lines coming in  from the battery so here's our high-voltage wires   and then just like on the other Prius we've got  a red and a black wire right here they go down   to the DC to DC converter alright and we've got  another electrical connection several well just   two more electrical connections and then straight  down right here I have a bracket that holds the   electrical connections in place okay next we'll  take off the capacitor assembly here and it has   connections everywhere so there's the four hold  down bolts that hold the whole capacitor assembly   to the housing and then we have two bolts right  here that are the DC connection straight from   our high-voltage battery then we have a single  connection to a new part that we've never had   before in the previous Prius called the reactor  and it's just a great big coil of wire it has 373   micro-Henries of induction capability and  then we also have a power and a ground DC   from the battery to the boost converter module  the one that controls the reactor so now let's   lift up the capacitor assembly this capacitor  assembly actually has a capacitor right here a   big capacitor right there and another one built  in over there so there's three capacitors   1130 micro-farads, 282 micro-farads,  and 0.1 micro-farads where all of the previous   ones were 2700 micro-farads in the other in the  previous generation inverter converter alright   now this great big module right here is what  I was trying to describe to you before the two   separate IGBT modules from the first generation  Prius and the circuit board make up this giant   piece right here oh I'm supposed to have my ground  strap on we have DC power coming in and out here   from the high voltage battery and then we have  three-phase connections going to MG2 back here   MG2 and then three-phase connections going to  MG1 in the front right there I'm not going to   take any of that off because it's the same  as what we've already seen in the previous   generation but these two parts right here  this big inductor suppressor which we've got a ground it's ground-controlled so we had battery  positive from the high voltage battery connected   there this module controls the grounds side  of that and then these modules also are held   down with a heat sink compound this boost control  module can go bad from inadequate grease or just   overheating over time let's say you've run low on  coolant and it's just overheated it should have   the heat sink compound underneath it it's got the  heat sink right there it's got the same serpentine   cooling passages that we had on the other one  right there and then the big inductor is just a   giant coil of wire big heavy coil of wire because  we have to handle a lot of current on acceleration   and deceleration I don't know the exact amount of  current I know the battery service plug grip has   a 150 amp fuse in it that's DC alright so here  comes the big inductor get the bolts out of it so the inductor here - electrical connections  there that go to the big coil of wire so this   terminal connects here this terminal connects  here we pulse DC current through it produces   a huge magnetic field then we release that  pulse the magnetic field collapses on itself   and through self-induction creates a reverse  polarity up to 300 volts pushing current in   the same direction that the high-voltage 201.6  volt battery is already sending it and it needs   heat sink compound for its heat sink down there  also so the boost converter module and this big   coil wire the inductor reactor these are what  they added to the inverter converter here from   the first generation to bump up the voltage and  all the subsequent generation Priuses and any   other Toyota hybrid that the GM's the the Fords  have these boost converter modules in them it's   a it's a great way to increase power without  having a monstrous high voltage battery   okay the other thing we need to look at that's  different on this inverter converter assembly   is this orange electrical connector up front it  has three wires so it's a three-phase electrical   connection to the air conditioning compressor  now the later model inverters only have a two   wire connection they supply DC high voltage  DC power to the AC compressor which then has   its own inverter internally so these are some  expensive air conditioning compressors to change   it to three-phase AC and drive the electric motor  so that you can have air conditioning when the   internal combustion engine is not running on the  first-generation Prius if you turned on the air   conditioning it would not go into idle-stop the  only thing left is to look at the parts inside   the inverter or inside the DC to DC converter I  have one that's already removed from the housing   so we don't have to remove it so let's go look at  that next okay so right here on my classroom wall   I have the inverter converter the DC converter  portion of that second-generation Prius right   here and the upper portion of it right there is  the air conditioning inverter and you can see   those three wires that come out and come down  to the electric air conditioning compressor the   lower portion the DC to DC converter there as  you can see has a transformer right there two   wires in two wires out and then an inductor  a coil of wire there one wire and one wire   out and its own driver circuit right there  to take the high-voltage DC and convert it   to low here's the schematic for the DC to DC  converter as you can see there is a center tap   transformer and for power transistors and  diodes for controlling the DC output over   here is the air conditioning system inverter  schematic and it has its own ID bTW as part of   this lower DC to DC converter that then drives  the air conditioning compressor all by its self and then here's the schematic for the second  generation Prius 2004 through 2009 we've got   the electric motors at the top the two sets of  IGBTs and transistors right there next the boost   converter power module and the reactor coil and  then the high-voltage battery and then the DC to DC   converter in the AC converter and the external  high-voltage ECU okay that was a lot to cover   and that was cutting it way down on information  because there's so much information here that   we go through on these inverter and converter  assemblies and maybe in future episodes when we   talk about each vehicle manufacturer platform we  can look at their inverter converter assemblies   along with their batteries that are unique in  future episodes here but amazing technology and   it's stuff that you as a service technician  can if you're patient and clean and can read   and follow technical written instructions can  make additional money doing but it could also   be a very expensive disaster if you aren't  following the instructions that don't have   the proper training and so on so this has  been a basically a summary of the inverter   converter components operation and service  what's serviceable in these and the second   generation Prius almost everything well I think  every I think every part in there of the major   parts is something that you can buy from the  Toyota dealer, Alright thank you for watching

Channel: WeberAuto

Views: 512,863

Keywords: Fusion Hybrid, WSU, converter, Prius, Aisin, CAT, Hybrid Inverter, Chevrolet Volt, Professor, Weber State Automotive, CCAR, NACAT, NATEF, ASE, Inverter, Hybrid Converter, Guy in wheelchair, Weber State University, STEM, Ford, Toyota, John D. Kelly

Id: Y7Vm-C4MsW8

Length: 90min 41sec (5441 seconds)

Published: Sun Sep 24 2017