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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%. [ABSTRACT FROM AUTHOR]

In this article, a new five-level inverter is developed by inserting a switched-capacitor (SC) unit into the traditional three-level neutral-point-clamped (NPC) inverter phase leg. The SC unit consists of two capacitors and one bidirectional switch, all of which withstand a quarter of the dc input voltage. While increasing the output levels, the performance is also improved in terms of power loss, common-mode voltage, switching stress dv/dt, and output filter. Compared to other five-level inverters like the conventional NPC and active NPC five-level topologies, the new solution not only reduces the number of components and simplifies the design but also has the advantage of self-balanced capacitor voltages. The analysis, simulation, and experiment indicate that the proposed inverter is suitable for a wide range of applications like renewable source grid-connected interfaces and motor drivers. Simulation and experimental results of grid-connected operation verify that the new inverter is capable of providing both active and reactive power to the grid. Its excellent performance is also experimentally evaluated by a 1.2-kW prototype and the measured efficiency is above 97% for a wide range of load. [ABSTRACT FROM AUTHOR]