Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Paul and Sabrina's Cheap 3 Phase Inverter (AC Controller) with Field Oriented Control

cts_casemod · 10-20-2014, 01:46 PM

If it was my inverter it would basically command a full deceleration, essentially acting as a brake. Extremely dangerous.

I have since sorted by giving a timeout if no pulses as received, switching the output. The error requires a shutdown/manual clear.

What I am working now is "unattended acceleration". If for some reason the encoder signal is corrupted the unit could theoretically command a high slip/torque/acceleration. This could either be positive or negative (regen) and the MCU would still be happy as it would be receiving pulses from the encoder, so no fault would be triggered.

I got around this by measuring the acceleration rate and cutting back values larger that what I would expect on a vehicle, however the acceleration rate for a 3rd gear is different from that from a 1st gear or even neutral and I am having trouble reaching a compromise.

I have lately thought about using a feedback current, measuring the set point and comparing with the average going into the motor. But shall we say this is not trivial on an induction machine.

I'm curious how you are planing to implement this Paul.

10-20-2014, 01:46 PM	#1248 (permalink)
cts_casemod EcoModding Apprentice Join Date: Nov 2012 Location: East Midlands Posts: 180 Thanks: 13 Thanked 81 Times in 52 Posts	If it was my inverter it would basically command a full deceleration, essentially acting as a brake. Extremely dangerous. I have since sorted by giving a timeout if no pulses as received, switching the output. The error requires a shutdown/manual clear. What I am working now is "unattended acceleration". If for some reason the encoder signal is corrupted the unit could theoretically command a high slip/torque/acceleration. This could either be positive or negative (regen) and the MCU would still be happy as it would be receiving pulses from the encoder, so no fault would be triggered. I got around this by measuring the acceleration rate and cutting back values larger that what I would expect on a vehicle, however the acceleration rate for a 3rd gear is different from that from a 1st gear or even neutral and I am having trouble reaching a compromise. I have lately thought about using a feedback current, measuring the set point and comparing with the average going into the motor. But shall we say this is not trivial on an induction machine. I'm curious how you are planing to implement this Paul.