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I made a control interface which accepts a standard PC joystick and provides a +/- 5 VDC signal to the Variable Frequency Drive (VFD). The motor automatically reverses depending on the polarity of the signal. The control interface also has a PIC18F4420 which has 5 active ADC channels which will read battery voltage and current, and DC link voltage and current. It drives a 2x16 character LCD display. It will also have an RS232 or USB interface to a computer which will log this data for later inclusion in a spreadsheet which can graph these quantities as well as power, efficiency, energy usage, and other quantities.
Here is a short video showing what it does:
http://youtu.be/R3gu4KSAgyI
I can provide circuit details and PIC code if anyone is interested. This is not a finished project but I will soon wire up the resistors to an op-amp so that it will actually be able to connect to the battery and link voltages, and shunts for monitoring the currents. I will probably start with a simple RS232 connection to stream the data to a PC, but I may replace the processor with a PIC18F4450 which is the USB version. That will be more convenient for newer computers. But I will most likely use one of my spare older computers which run Win98, XP, or Vista. Since I will be using this on an off-road utility vehicle (converter riding mower or garden tractor), it needs to be rugged and/or expendable.
It is also possible to use an Ethernet-enabled PIC so that the tractor will be essentially a web page server which can be connected to the internet through my WiFi router, or maybe directly to an Android Net Tablet, like my Archos 7, or an iPhone. It could also be set up for remote control.
I may also use the X-axis of the joystick so that I can operate two VFDs and two motors, one on each rear axle. That could make the vehicle a zero turn radius (ZTR) machine. The possibilities are limitless and exciting, but "gittin' 'er done" is the kicker!
Here is a short video showing what it does:
http://youtu.be/R3gu4KSAgyI
I can provide circuit details and PIC code if anyone is interested. This is not a finished project but I will soon wire up the resistors to an op-amp so that it will actually be able to connect to the battery and link voltages, and shunts for monitoring the currents. I will probably start with a simple RS232 connection to stream the data to a PC, but I may replace the processor with a PIC18F4450 which is the USB version. That will be more convenient for newer computers. But I will most likely use one of my spare older computers which run Win98, XP, or Vista. Since I will be using this on an off-road utility vehicle (converter riding mower or garden tractor), it needs to be rugged and/or expendable.
It is also possible to use an Ethernet-enabled PIC so that the tractor will be essentially a web page server which can be connected to the internet through my WiFi router, or maybe directly to an Android Net Tablet, like my Archos 7, or an iPhone. It could also be set up for remote control.
I may also use the X-axis of the joystick so that I can operate two VFDs and two motors, one on each rear axle. That could make the vehicle a zero turn radius (ZTR) machine. The possibilities are limitless and exciting, but "gittin' 'er done" is the kicker!