ABSTRACT

In this paper, a new single-phase seven level inverter with reduced device count is introduced. The structure can boost the input voltage by synthesising the capacitors’ voltages in predetermined current paths. A single DC voltage source is utilised to generate the output AC staircase waveform, which is facilitated via Nearest Level Control. Self-voltage balancing ability, less number of semiconductor devices, high efficiency and control simplicity are the most significant inherent attributes of the proposed circuit. It is also noticeable that in this configuration neither bulky transformer/inductor nor filters are applied. Power loss calculation and required capacitance of the proposed inverter are investigated and theoretical efficiency of 93.31% was reached. Moreover, the proposed converter operates under various load conditions with lower Total Harmonic Distortion compared to recent topologies. Ultimately, operating principles of the proposed D-Type seven-level Inverter and simulation results in MATLAB SIMULINK environment are validated by experimental ones obtained from the laboratory prototype.

摘要

本文介绍了一种减少设备数量的新型单相七电平逆变器。该结构可以通过在预定电流路径中合成电容器的电压来提升输入电压。单个直流电压源用于生成输出交流阶梯波形，该波形通过最近电平控制实现。自电压平衡能力、较少数量的半导体器件、高效率和控制简单是所提出电路的最重要的固有属性。同样值得注意的是，在这种配置中，既没有应用笨重的变压器/电感器，也没有应用滤波器。对所提出的逆变器的功率损耗计算和所需电容进行了研究，理论效率达到了 93.31%。而且，与最近的拓扑相比，建议的转换器在各种负载条件下运行，总谐波失真更低。最后，通过实验室样机获得的实验结果验证了所提出的D型七电平逆变器的工作原理和在MATLAB SIMULINK环境下的仿真结果。