A CCM based Average Current Control Technique for Chopper Integrated Single-phase ANPC Inverter to Minimize Voltage Ripple

Abstract

This paper proposes a continuous conduction mode (CCM) based average current control technique for a chopper integrated single-phase five-level active neutral point clamped inverter (ANPCI) to minimize the voltage ripple in dc-link capacitors. For balancing the dc-link capacitor voltages and the flying capacitor (FC) voltage of ANPCI, a voltage balancing algorithm has been implemented which results in negligible voltage ripple for FC. However, voltage ripple in dc-link capacitors is still significant and to minimize it further, an external chopper circuit is employed at the dc-link of the ANPCI. To regulate the chopper inductor current, it is proposed to use average current control technique for the chopper integrated ANPCI. The average current controller operating in CCM is implemented along with the capacitor voltage balancing algorithm and it produces less ripple in the capacitor voltages compared to the discontinuous conduction mode techniques. Also, the chopper current becomes a nearly sinusoidal waveform. Finally, the ANPCI and chopper integrated ANPCI are implemented in hardware and their performance is compared.