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Just the motors inside the transmission. The input shaft will be locked (I need to design some sort of fixture to hold it). This will allow MG1 to act as a motor through a fix reduction. The speed rating of MG1 is the same as MG2 in the Camry hybrid (14k rpm), so this configuration will limit me to 110mph due to MG1 speed. MG2 has two speeds, controlled by clutches and a gearset in the transmission. There's an electric oil pump that allows EV mode in the original transmission. I'm hoping that this pump feeds the same oil circuit as the mechanical pump inside. The mechanical one will never turn as it's coupled to the input shaft. I'll need to make sure that the clutches/solenoids get hydraulic pressure as well as the oil cooling for the stators and lubrication of the bearings. I'm trying to get a second transmission that I can tear down to confirm the operation of the oil pump, but if I have to, I'll tear this one down to make sure. If I need to drive the internal oil pump as well as the electric one, I'll rig up a BLDC motor to drive the pump shaft. But I'm really hoping I can avoid that.I'm looking forward to watching this with interest
Are you using a main motor mated to the transmission in place of the engine as well? or just the integral transmission mounted motors?
Here's a link to the paper that describes the transmission (mine is the same minus the transfer case). The GS450h inverter from this same generation is identical to the Camry hybrid inverter. There's also a detailed teardown of that from the same folks.Ok thanks, that makes sense. I don't follow the schematic though, I'll google a bit on it. I wish you every success and am following with interest.
Very goodHi Jeff,
I have been following your progress! I was tempted to do a conversion very similar to yours (MR2 with either Prius or Camry transmission), but decided to go this route instead due to the performance available from the Lexus transmission.
I'm using vector control for mine (manually for now at least). I haven't connected the current sensors yet so I'm just adjusting the angle of the voltage vector relative to the rotor manually. It's good enough for low speeds and the 12v that I'm testing with.
Regarding switching to BLDC-type commutation, the changeover from FOC to 6-step might not need to be an actual change. If you let your current-control loops saturate at high speed (attempting to achieve current that is not possible due to field weakening), they will go in to overmodulation. This causes the sine waves to transition to square waves. Resolution also shouldn't be much of a problem since at high speeds, distortion in the voltage waveform is filtered by the stator inductance in to a sine wave (or something close enough) anyway. I don't think I'll need to go that route myself, since my pack voltage will be so high. Time will tell though.
I have my own idea for charging, which is different from yours.
Send me a PM before you get here and we'll arrange something!
-Vincent