Digital Control of Electrical Drives
By using digital controllers, vector control strategies for asynchronous and permanent magnet synchronous drives are developed. These include speed as well as torque control and are based on either field-orientation methods or direct torque control techniques. The digital controllers used are digital signal processors (DSPs) from Analog Devices or Freescale (Motorola). Signals from resolvers are digitized by using a self-made converter and transmitted to the DSP. Current and voltage measurements from self-build inverters are converted by ADCs, available on the DSP evaluation boards. These signals together with the signals from the resolver are used to generate PWM signals required to control the machine in a stable and efficient manner.