To drive a 600V 3-phase 4-pole induction motor, with copper rotor, small air-gap, forced air cooling,expected to output a maximum hp of 40kW with real time throttle and dynamic torque load.
(This motor is halfway through its fabrication, most parts are waiting for final calculation before final C&C)

Reason for 600V is to reduce I^2R losses as well as conduit sizes since the motor contruction is rather compact because, you guessed it, is used for an EV(electric vehicle) project, lol.

Vector control start-up would be desireble.

Right now i dunno wether this proxy/pseudo inverter of mine which has a 6-step 3-phase squre wave will kill off my motor.

Is using PWM gating to overlap the 3-phase gating a good way to control voltage? I really dunno how a sine wave can be artificially produced by circuits yet, except using capacitors to smoothen the edges of the square wave until they become round, but that will work only in fixed frequencies, and mine is a variable frequency. Has anyone hooked up the outputs of a commercial 3-phase VFD to an oscilloscope? How does it look like with and without the induction load?

The analog-to-digital conversion of motor sensors' inputs to measure both current and speed can be done and PLC might not be an issue. The PLC's job is to make sure the frequency of the inveter is faster than the rotating manegtic field of the rotor by a 3-5% slip at any given moment depending on rpm. Throttle is tied to voltage, with 0% throttle meaning 0V or 0% duty cycle of the fixed frequency pwm. The 3-phase gating will run as usual when throttle is at 0% but AND gates will cut of 3-phase signal to the IGBT drivers. Yes, my 3-phase signal is ANDed to a PWM signal for voltage control.


Thanks for helping.