A Fast-Processing Implementation Method of Virtual Space Vector Modulation for the Impedance-Source Three-Level Inverter

The impedance-source (IS) three-level inverter has been put forward to implement buck-boost operation and obtain multi-level output waveforms. The virtual space vector modulation (VSVM) can balance the neutral-point voltage (NPV) in full power factors and modulation indices. This brief further proposes a fast-processing implementation method of VSVM for IS three-level inverter. According to the relationship of three-phase modulation waves, a proper differential-mode voltage injection scheme is developed to control the NPV balance actively. In order to boost the dc input voltage, the maximum and minimum modulation waves are further moved upwards and downwards, and the shoot-through (ST) states are properly generated without affecting the normal ac output voltage. Doing so, the VSVM strategy for IS three-level inverter is simply implemented by carrier-based modulation (CBM) approach. The effectiveness of the proposed method is verified by experiments.