Abstract：The single-phase cascaded H-bridge (CHB) inverters for grid-connection photovoltaic (PV) systems have been explored with the features of modular, low harmonics and so on. The power harvested from PV modules are different exceedly because of serious environment, or even one or more modules' power are equal zero that becoming dummy units which affect system's stability and redundancy. This paper proposes an improved hybrid modulation which is a mix of "staircase + pulse width modulation (PWM) +sorting algorithm". This method adopts low frequency staircase modulation to expand stable operating region fundamentally, and uses high frequency PWM modulation to shape the current and decrease its total harmonic distortion (THD). Moreover, sorting the errors of dc voltages to get maximum power point tracking (MPPT) control, then analyze this method's stable operating condition from active power point. The proposed hybrid modulation have simple control structure, and can control the dummy unit effectively with individual MPPT. Finally, the simulation and experiment results validate the effectiveness and feasibility of the developed ideal.
王付胜, 张德辉, 戴之强, 杨乐. 级联H桥光伏并网逆变器混合调制策略[J]. 电工技术学报, 2016, 31(增刊): 137-145.
Wang Fusheng, Zhang Dehui, Dai Zhiqiang, Yang Le. A Hybrid Control Scheme of Cascaded H-Bridge Inverters for Grid-Connection Photovoltaic Systems. Transactions of China Electrotechnical Society, 2016, 31(增刊): 137-145.
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2016, Vol. 31 
