Seven-Level Switched-Capacitor Inverter with Triple Boosting and Sensor-Less Voltage Balancing Capability

This paper introduces a versatile single-phase seven-level inverter for integrating lower voltage renewable energy sources to the higher voltage amplitude power grids. The input voltage was increased by combining the voltage of the capacitors in the predetermined current paths. The output staircase waveform was formed by using a DC voltage source, two capacitors, and the aid of the phase disposition pulse width modulation (PD-PWM) strategy. The self-voltage balancing ability of the capacitors without the need for any external controllers nor sensors, high efficiency, and ease of operation were the most important features of the proposed converter. Requiring fewer semiconductor devices compared to other inverters mentioned in recently published papers ensures the superiority of the proposed boosting multilevel inverter. The ability to increase the input voltage by three times at the output in addition to the ability to self-balance the voltage of the capacitors without the use of a side control circuit or sensor were other advantages of the proposed structure. Furthermore, by calculating the power losses and circuit capacitances, 95.8% efficiency was obtained. Finally, the performance of the proposed seven-level inverter under different load conditions was simulated in MATLAB SIMULINK environment and the results were confirmed by the results obtained from the laboratory prototype.