An SMC-ESO-Based Distortion Voltage Compensation Strategy for PWM VSI of PMSM

The nonlinear factors of the voltage source inverter (VSI) lead to an error between the reference voltage and output voltage, which causes the voltage and current distortion and torque fluctuation. It is necessary to reduce its impact on the fields, such as parameter identification, sensorless control, and motor drives. Thus, a distortion voltage compensation strategy based on sliding mode control (SMC) and extended state observer (ESO) is proposed in this article. First, inverter nonlinearity factors (INFs), such as the dead time of the inverter, the switching delay, and the voltage drop of the switching tube and the diode, are analyzed, and the theoretical compensation voltage is obtained with reference to the nominal parameters. Then, an ESO considering the theoretical compensation voltages is employed to observe the distortion voltage online caused by INF and motor parameters perturbations under different operating conditions. In addition, the SMC is used to improve the dynamic compensation effects of the system. The Lyapunov theory demonstrates stability. Finally, the proposed method is validated by a VSI feeding a surface permanent magnet synchronous motor (SPMSM) without an additional hardware circuit. Simulation and experimental results prove the advantages of the proposed method.