VESC controller and power stage
Controller undergoing double pulse testing to verify function
I'm just getting started with VESC, but I've designed 10-20kW power stages previously; however they were used with different controllers like TI Instaspin and another FOC controller made by Lebowski from endless-sphere.com
I've got my first prototype up and running and so I figured I'd share a bit. I had it spinning my first motor in FOC a few days ago. The power stage is currently using IRPF4568 150V MOSFETs for initial testing, however the one I'm assembling next is using 200V IRF200P222 rated MOSFETs since this has proven successful. With the IRF200P222 devices it should be capable of 150V DC bus, leaving 50V of overhead for overshoot issues which the RCD snubbers should assist with.
I've got more info about my build on endless-sphere.com at this link:
https://endless-sphere.com/forums/viewtopic.php?f=30&t=106688
The VESC controller I created has a lot of extra safety features built in. It is similar in design features to Axiom and has a lot of fault detection to maximize chances of the everything surviving a catastrophic event such as shoot through from shorted phase leads.
The gate driver uses a desaturation detection circuit which shuts down the gate drive in about 5us if a shoot through event is detected. It then outputs a fault to an error handling board made of discrete logic which then triggers a transceiver placed between the PWM output and the gate drive to shut down as well as triggering the MCU to shut down. Any over current or over voltage event is handled in hardware, also shutting down PWM to the gate drive and triggering a fault on the MCU.
Here is a video of my controller running a 120100 70KV out runner in FOC
Here is one of it outputting 180A phase into some large motors with shorted leads. This is pretty close to a locked rotor scenario which is a worst case load condition. The VESC firmware did a great job at maintaining rotor position tracking.
Next up I need to design an enclosure and fix some minor errors on the PCB since this is a first draft prototype. The PCBs will either be 4-6oz copper on all layers or have additional external bussing added for higher current. I'm also going to expand out to 18-24 MOSFETs in total for higher current use. I also have a power stage which should be capable of +1000A in the works, but it requires machining work, and that's not cheap.
Any chance of a schematic?
You said on Endless Sphere you wanted to do the fault protection in discrete logic, why not add a small FPGA? Or even a secondary MCU?
Looking good and I'm loving the direction you're going in.
I'll probably post the schematic at some point, but I still have corrections which need to be made found during this prototype. Discrete logic was chosen because I didn't have the time to learn how to implement an FPGA (I'd be starting from no experience). I have done MCUs before for fault handling, but found they weren't quite fast enough to provide the feedback I wanted. Discrete logic was chosen because it's fast, reliable and low cost, but it's not small so it uses a dedicated board. There is several hundred hours of design in this already as proper layout takes quite a bit of time. Being familiar with the TD350E gate driver I'm using probably saved me significant time. Gate driver design is one of the most critical parts of a power stage. I want to switch to a better gate driver, but it would probably take me 50-100hrs of research, design and qualifying it on the bench.
Z, we should do a zoom meeting or something to discuss. I can't stand the delay in idea prepossessing my current level of passion and interest in getting a controller together.
I'm looking at a couple of gate drivers 2EDL23N06 as well as UCC21222 .. I could help you skip over the 100's of hours in qualifying time and maybe you can save me from blowing up a couple of half bridges.
Mo