docs

README.md

@@ -1,3 +1,35 @@
 # STM32 variable frequency drive controller
 
-This project aims to be an open source sensorless VFD. Don't get your hopes up yet, as it currently does nothing. Maybe check back later.
+This project aims to be an open source torque controller for AC induction motors.
+
+## Hardware
+
+This software runs on an STM32. In addition, the following hardware is required:
+
+* 6 x IGBT or MOSFET
+* 6 x Isolated FET drivers
+* 3 x Hall effect current sensors
+* Rotary encoder
+* A large film capacitor
+
+An example schematic can be found here: https://nutty.tk/inverter3.pdf
+
+## Overview
+
+The software generates a 3-phase output using PWM. The frequency and voltage
+are adjusted to create a torque proportional to the "throttle" input.
+
+## Algorithm
+
+The algorighm is very simple and is based on setting the slip of the motor.
+The output frequency is the shaft frequency plus a slip, where the slip is
+proportional to the throttle input. The current is controlled to keep it
+proportional to the slip (up to the input voltage).
+
+## Testing
+
+So far this has only been tested up to 1A @ 48VDC on a 250W motor. It is my
+hope that this should scale to larger builds for electric vehicle use. More
+experimentation will follow.
+
+My low power test build: https://imgur.com/a/IR173Ng

make.sh

@@ -7,7 +7,7 @@ arm-none-eabi-gcc $CCOPTS -c startup_stm32l476xx.s -o startup_stm32l476xx.o
 arm-none-eabi-gcc $CCOPTS -c system.c -o system.o
 arm-none-eabi-gcc $CCOPTS -c uart.c -o uart.o
 arm-none-eabi-gcc $CCOPTS -c main.c -o main.o
-#arm-none-eabi-gcc $CCOPTS -S -c main.c -o main.s
+arm-none-eabi-gcc $CCOPTS -S -c main.c -o main.s
 arm-none-eabi-gcc $CCOPTS -T STM32L476RG_FLASH.ld -Wl,--gc-sections *.o -o main.elf -lm
 arm-none-eabi-objcopy -O binary main.elf main.bin
 #st-flash write main.bin 0x8000000