Self-Balanced Multilevel Inverter With Hybrid Double- and Half-Mode Switched Capacitor

Abstract

Two 17-level inverters based on switched capacitor (SC) are presented in this article. Each of them involves two SC units and a neutral-point-piloted unit. A total of four pairs of transistors, a bidirectional switch, two pairs of diodes, and three pairs of capacitors are employed. All of the switching components are controlled by six pulsewidth modulation signals and all capacitors’ voltages are self-balanced. With an improved selective harmonic eliminated modulation strategy, low-order harmonics are effectively suppressed and switches operate in low switching frequency. In addition to the use of fewer components, high-quality output voltage shape is benefited from the unique topology and reduced capacitor voltage ripple accumulation. Experiment results demonstrate the excellent performance of the proposed inverter. High efficiency is also achieved and the maximum value is up to 98.05%.