Emmanouil Tzorakoleftherakis, MathWorks
Implement and automatically tune a field-oriented control system that controls the flux and torque of a three-phase induction motor. The control system consists of four PI controllers. The rotor speed and flux controllers in the outer loop provide references to the current controllers in the inner loop using the measured rotor speed and three-phase stator current as well as the Clarke and Park transformations. The four PI controllers are tuned using the Closed-Loop PID Autotuner block in a single simulation. This block injects an excitation signal during closed-loop plant operation to estimate the plant frequency response and automatically tune the PID gains. Based on the PID outputs, a PWM Generator module is used to generate the gate control pulses for the semiconductor switches in the machine-side power inverter, such that the desired flux and torque specifications are met. The Closed-Loop PID Autotuner block is part of Simulink Control Design™ since MATLAB® R2018a and the induction motor and power converters have been modeled in Simscape Power Systems™.