Sensorless Fuzzy Variable Speed Control with Torque Optimization for the Improvements of Single Phase Capacitor-Run Induction Motors

The single phase capacitor-run motors are the ones which have the earliest and widest applications. The improvements of variable speed for them have the important meaning to improve their operation characteristics and to save their dissipating energy. So, the sensorless control scheme is presented to aim at controlling the speed and the torque simultaneously. At first, The design of the rotor speed estimator is carried on, which the rotor speed can be obtained according to the general mathematical model of the single phase capacitor-run induction motor and the rotor estimating speed be used instead of the real rotor speed. Then the speed reference signal and the rotor speed estimating signal are transferred each by different tracking differentiators. The design of the hybrid fuzzy tracking differentiator controller is completed, which the output signal of the two tracking differentiators are served as the fuzzy controller input signals. The fuzzy controller output signal is changed to the speed control signal by the inverter. The torque optimization is made by the torque optimizator adapting to the variable speed. The torque optimizator output signal is changed to the adjustable switched capacitor PWM signal by the PWM generator. The control scheme presented is realized by the physical prototype. The experiment results prove the total control system performance is correct. And it has the advantage of the sensorless speed measure, the easy realized control and the high performance.