Unified Control Technique for Z-Source Inverter

Based on space-vector PWM (SVPWM) techniques, this paper proposes a new unified voltage vector of the Z-source inverter, which is composed of the traditional voltage vector and the unique boost factor of the Z-source inverter. On the basis of this unified voltage vector, a close-loop unified control technique is proposed from the viewpoint of global inverter operation, which can improve the stability of the inverter system, keep the minimum voltage stress across the switches with variable input voltage, and implement the linear control of the output voltage. In addition, only the output voltage needs to be sensed in the unified control technique, unlike the traditional control methods that use both the output and capacitor voltages. This control method is also simple and easy implementation for digital control. Furthermore, various conventional voltage-source inverters (VSI) SVPWM control strategies (include internal current control) can be applied to the unified control technique. The feasibility of the proposed control method has been verified by the simulation and experimental results.