A new direct peak dc-link voltage control strategy of Z-source inverters

This paper proposes a new direct peak dc-link voltage control strategy of Z-source inverters. For Z-source inverters, the peak dc-link voltage is the actual voltage fed to the inversion stage. Controlling the peak dc-link voltage at the constant level can effectively decrease the voltage stress and simplify the design process of the inversion stage. A direct peak dc-link voltage detection method is developed with a simple sampling circuit, and then controlled directly. Therefore, the constant peak dc-link voltage can be achieved in different input and load conditions. The peak ac output is calculated in real-time by sampling the ac phase voltage, and it is controlled to the desired value without steady-state error. With the proposed direct peak dc-link voltage control and peak ac output control, both the peak dc-link voltage and ac output is controlled to a desired level under different input and load condition. Experimental results are presented to demonstrate the feasibility of the proposed control strategy.