Adverse Influence of PLL on the Bus Voltage Feed-Forward With Band Pass Filter Under Harmonic and Unbalance Condition

Abstract

To improve the system performance, such as suppress the system harmonics, restrain the system resonance, etc., the bus voltage feed-forward (BVF) is often added in the control of three-phase inverter. Specially, under harmonic and unbalance condition, the band pass filter (BPF) is embedded in the path of BVF to control the selected frequency components. While, the influence of Phase-Locked Loop (PLL) on this control is ignored in the prior. In this letter, the multi-frequency model of the BVF with BPF considering the time-periodic trajectory of PLL is proposed. Afterwards, the adverse effect of PLL on BVF with BPF under harmonic and unbalance condition is explored and some new finds are given. Lastly, the theoretical analysis is verified by experimental results.