Combined SHE-LLCL Design for a Real Case Photovoltaic Power Station

[摘要] The purpose of this study is to improve control performances of a real case photovoltaic (PV) power station. By considering the cable’s inductance, the LCL filter becomes an LLCL filter with a resonant behavior. To avoid this resonance from contaminating the system and to ensure that the studied case could be realized in the worldwide, a control design is highly required. This is achieved through two PWM strategies: the selective harmonic elimination (SHE) and the selective harmonic modulation (SHM). A brief comparison is highlighted in this paper. The obtained results confirm that SHE strategy presents really a harmful disadvantage compared to SHM (Franquelo et al. in IEEE Transactions on Industrial Electronics 54(6):3022–3029, 2007, Napoles et al. in IEEE Transactions on Industrial Electronics 57(7):2315–2323, 2010), which could impact the current harmonics rejected on the grid and breaks grid codes. An attention has to be paid to the unwanted effect of the SHE strategy as well as the LLCL poor quality attenuation. An efficient combined SHE-LLCL strategy is proposed to improve the performance of a real case grid-connected PV inverter thanks to the flexibility provided by the LLCL filter and the SHE strategy’s simplicity. Obtained results show better performances over traditional researches.

[学科分类] 自动化工程

[关键词] Photovoltaic power station;Three-phase inverter;Selective harmonic elimination;Selective harmonic modulation;LCL filter;LLCL filter;Harmonic current spectrum;Grid codes