Reduction of Voltage Ripple for Single-phase Chopper Integrated ANPCI based on Hysteresis Voltage and Chopper Current Control Methods

This paper presents the control and operation of single-phase chopper based five-level active neutral point clamped inverter (ANPCI) to reduce voltage ripple of DC-link capacitors. A capacitor voltage balancing algorithm is implemented to regulate the flying capacitor (FC) and DC-link capacitor voltages. As the voltage ripple of DC-link capacitors is significant, large DC-link capacitors are required to generate an acceptable five-level output voltage waveform. Hence, to reduce the voltage ripple and size of DC-link capacitors and FC, a chopper based ANPCI (CANPCI) is implemented with two control methods, viz., hysteresis current control and hysteresis voltage control methods. These control methods can also limit the maximum chopper inductor current as desired. The ANPCI and CANPCI are implemented in PSCAD/EMTDC simulation and hardware prototype along with the capacitor voltage balancing algorithm and their results are compared.