Jeremy Harris
100 MW
Ages ago Lebowski was kind enough to let me have a couple of programmed dSPIC30F4011 chips, as used in his neat controller and I promised to start a thread here when I started making a controller with them. I have plans to build a pretty big controller with one of the chips, but thought I'd start off by making a low power one to replace the 6 FET Xiechang I'm currently using on the Swift folder with the other. This is just a preview of my plans for now, as I need to get on and finish the PCB layout and get the remaining parts ordered.
The case I'm going to use is a small Hammond extruded alloy box, their part number 1455K1201 (see here: http://www.hammondmfg.com/1455.htm ). This is around the same size as a 9 FET Xiechang case, but I'm hoping that I will be able to fit the controller and an RFID power switch, battery charge monitor etc into it. I have the PCB layout done for the power board, including provision for three ACS758 current sensors, and just need to finish the layout for the piggy-backed "brain" board that will hold the dSPIc and the voltage regulators, then make a start on the other board that will hold the power switch and charge monitor stuff.
This isn't a high power beast, I'm using just six IRFB3077s and 50A bidirectional phase current sensors. The idea is to get to grips with tuning Lebowski's controller with a low power unit where I can better prevent the release of magic smoke if I get something wrong. The main reason I want to start out with a small controller like this is that the Swift with the Q100 motor needs much better throttle control. The combination of the high motor rpm, two stage gear reduction and speed command throttle isn't great on a small wheel bike, it makes for a jerky, rather on/off, throttle response, due in part to the wide motor rpm range, I think, together with a coarse speed command throttle. I'm hopeful that current mode throttle control will get around this problem and that the motor will also be quieter when driven with a better waveform.
One thing I'm slightly concerned about is that the controller needs the motor to be spun in order to calibrate the Hall timing, and the only way I can do that is to spin the motor backwards, as it's a small geared hub. I'll need to check with Lebowski if there's a way of reversing the calibration process to take account of this (I think there is, but haven't got that far in understanding how it works, yet).
The case I'm going to use is a small Hammond extruded alloy box, their part number 1455K1201 (see here: http://www.hammondmfg.com/1455.htm ). This is around the same size as a 9 FET Xiechang case, but I'm hoping that I will be able to fit the controller and an RFID power switch, battery charge monitor etc into it. I have the PCB layout done for the power board, including provision for three ACS758 current sensors, and just need to finish the layout for the piggy-backed "brain" board that will hold the dSPIc and the voltage regulators, then make a start on the other board that will hold the power switch and charge monitor stuff.
This isn't a high power beast, I'm using just six IRFB3077s and 50A bidirectional phase current sensors. The idea is to get to grips with tuning Lebowski's controller with a low power unit where I can better prevent the release of magic smoke if I get something wrong. The main reason I want to start out with a small controller like this is that the Swift with the Q100 motor needs much better throttle control. The combination of the high motor rpm, two stage gear reduction and speed command throttle isn't great on a small wheel bike, it makes for a jerky, rather on/off, throttle response, due in part to the wide motor rpm range, I think, together with a coarse speed command throttle. I'm hopeful that current mode throttle control will get around this problem and that the motor will also be quieter when driven with a better waveform.
One thing I'm slightly concerned about is that the controller needs the motor to be spun in order to calibrate the Hall timing, and the only way I can do that is to spin the motor backwards, as it's a small geared hub. I'll need to check with Lebowski if there's a way of reversing the calibration process to take account of this (I think there is, but haven't got that far in understanding how it works, yet).