DC-link Voltage Sliding Mode Control of Z-source Inverter for High Speed Permanent Magnet Motors

When the high-speed permanent magnet synchronous motor (PMSM) fed by Z-source inverters operates in a large speed range, it is necessary to control the DC-link voltage in real time. In order to abate the adverse effects of non-minimum phase characteristics on the system when permanent magnet synchronous motors operate at high speed, this paper proposed a sliding-mode control method for Z-source inverter to control output DC voltage of impedance network. In this paper, a sliding-mode controller of DC-link voltage is designed based on the indirect control of capacitor voltage, which takes the integration of inductance current error, inductance current error and capacitor voltage error as state variables. Also, the control law and the range of sliding-mode coefficients which make the system satisfy the existence and stability conditions are derived. Thus the designed controller has faster dynamic response than PI controller, and can ensure the stability and robustness of the system when the working state changes in a large range. Finally, the validity of proposed controller is verified by simulation and experiment.