Resonance propagation analysis for inverter‐dominated multi‐AC‐bus systems

Abstract

Abstract Harmonic resonance in a system with multiple inverters connecting to a single AC bus has been well studied in previous literature. However, in reality, a large number of distributed inverters are often classified into several groups using a few matching transformers. Due to the impact of matching transformers’ leakage impedance, the entire system presents a multi‐AC‐bus grid‐tied system with more complicated resonance interactions. In this work, a completed analytical method is developed. It reveals that there are different resonance types in such a system, and the determining factors of these resonance types are analysed. Moreover, the simplified calculation formulas for each resonance frequency are derived. For parallel resonance problems, under normal circumstances, the harmonic source tends to cause resonance with its neighbouring converters, but it has little effect on remote converters with long electrical distances. However, under special circumstances, the harmonic source has almost no effect on neighbouring converters, but causes resonance with the remote converters. In this situation, the resonance path passes through the transformer and multiple AC buses. Verification results are provided to validate the correctness of theoretical analysis.

Keywords

• Control of electric power systems
• Distributed power generation
• Distribution networks
• Power supply quality and harmonics
• Power convertors and power supplies to apparatus