Wide Bandwidth Control for Multi-Parallel Grid-Connected Inverters with Harmonic Compensation

• Main Authors: Jingrong Yu, Limin Deng, Dongran Song, Maolin Pei
• Format: Article
• Language: English
• Published: MDPI AG 2019-02-01
• Series: Energies
• Subjects: harmonic-compensation grid-connected inverters; multiple parallel; control bandwidth; virtual impedance; capacitor voltage feedback
• Online Access: https://www.mdpi.com/1996-1073/12/3/571

This paper proposes a virtual impedance-based bandwidth control method for multi-parallel harmonic-compensation grid-connected inverters (HCGIs). Firstly, the influence of the resonance points caused by the interaction of multiple HCGIs on the control bandwidth is analyzed, and the analysis result shows that the control bandwidth becomes narrow due to the appearance of a new resonance point. Then, to increase the control bandwidth of multi-parallel HCGIs, six different types of virtual impedance circuits are constructed and compared, and the bandwidth control method based on virtual impedance by capacitor voltage feedback is proposed. Following that, the relationship between feedback coefficient and bandwidth is established, the design approach of parameters for the proposed method is presented. Finally, the proposed method is confirmed by the simulation and experimental tests. The simulation and experimental results show that the proposed control method can effectively shift resonance frequencies right to solve the issue of control bandwidth reduction in multi-parallel HCGIs systems, while without affecting the low-frequency harmonic current compensation.