Fuzzy control of a sigma delta inverter drive for electromechanical positioners

This paper describes an elastic fuzzy controller with a sigma-delta driven power inverter for electromechanical positioners. The computerised fuzzy algorithm calculates the required input control voltage for the electromechanical converter. As the desired electrical power is usually quite high, the input control voltage is first applied to a switching power inverter, which reproduces its input signal by a PWM technique. To obtain a power inverter control subsystem, independent of semiconductor, motor and load characteristics, a robust sigma-delta modulator sampling only the output voltage is used. To prevent overcurrents in this voltage inverter, an active current limiter is built in the main semiconductor switches. Presented simulation and experimental results show that the performance of the system is independent of system parameters and remains essentially unchanged when driving different types of motors.