Hi all, some things from me:
1. system voltage; low voltage is synonimous to low efficiency, high voltage - high efficiency, and you can bouth safely die from 144VDC and 700VDC as either from gas evapours from your regular combustion engine, when lighted up in perfect air to fuel ratio; it all depends on how safely you make it. So please don't go low voltage, better higher as much as you can get. Higher voltage means also less copper, less weight, less amps to waste for hauling higher weight. IGBT's costs are AMPS not voltage, so if higher voltage it's less amps, less amps less costs. And deffinettly IGBT rating is 1/2 amps RMS and 1/2 volts RMS due to mistic spikes that doubles DC voltage so if DC volts are 600 IGBT must be 1200V (don't ask me why, I am not Tesla and don't understand electricity).
2. cooling/heating; controller and PM motor deffinettly should have liquid cooling. when rettrofitting car with electric engine you have from combustion engine radiator and cabin heating liquid type, so all the waste heat from IGBT's and PM motor you can get in cabin for heating it. Also working with industrial PM motors for machines dramatically falls torque momentum, even more than 2/3ds from nominal, if temperature gets over 50°C on body of motor and when cooled to 20°C it get's back full torque.
3. speed feedback. don't go low cost optical, I have seen what happens to motors (PM and AC closed loop) when they lose signals from optical encoders, they just rev up to full speed at full power or start to jog fwd rew at full power and this is no good for EV...... the best solution what I see for EV is resolver (other way relaiable optical are out of costs for diy they come in pricing 500usd and up) we should look up for some ic's like this:
Synchro/Resolver to Digital Converters | Analog to Digital Converters | Analog Devices they are costly but weakest link for security is speed feedback, if you lose IGBT's controller just dies, if you lose controller evrything stops, but if you lose speed feedback controller can make up very a lot different fancy things which can lead to fatal endings to the story......
4. please have fun before you do something and while you are doing something, because otherway evrything will be crap what you are doing and pushed out of second end!!!
And come to Latvia to have some beers for fun. And think only good thoughts, because they make you good and celebrate life for full speed and rews etc. feel free