Optimal Selective Harmonic Control for Power Harmonics Mitigation

This paper proposes an internal model principle (IMP)-based optimal selective harmonic controller (SHC) for power converters to mitigate power harmonics. According to the harmonics distribution caused by power converters, a universal recursive SHC module is developed to deal with a featured group of power harmonics. The proposed optimal SHC (OSHC) is of hybrid structure: All recursive SHC modules with weighted gains are connected in parallel. It bridges the real “nk ±m order RC” and the complex “parallel structure RC”. Compared with other IMP-based control solutions, it offers an optimal tradeoff among the cost, complexity, and performance: high accuracy, fast transient response, easy implementation, cost effective, and also easy to design. The analysis and synthesis of the OSHC system are addressed. The proposed SHC offers power converters a tailor-made optimal control solution for compensating selected harmonic frequencies. Application examples of grid-connected inverters confirm the effectiveness of the proposed control scheme.