Research on Harmonic Compensation Strategy of Single-phase CHB Photovoltaic Grid-connected Inverter System

doi:10.11985/2023.02.022

Abstract

Abstract:

Affected by partial shading, self damage and other factors, the transmission power between H-bridge modules of single-phase cascaded H-bridge photovoltaic grid-connected inverter system is unbalanced. As a result, the H-bridge module with high transmission power is prone to overmodulation, which leads to the deterioration of grid current and even affects the stable operation of the system. Therefore, an optimized third harmonic compensation strategy is proposed, through the accurate calculation of the third harmonic compensated by the overmodulation module, the amplitude of their modulation wave is 1. At the same time, combined with the optimal distribution of inverse third harmonic among the normal modules, the overmodulation of each H-bridge module is avoided to the maximum extent. The simulation model is built in Matlab/Simulink, and the simulation results of the proposed control strategy are compared with the conventional third harmonic compensation strategy and hybrid modulation strategy, and the excellent performance of the proposed control strategy is verified.

Key words: Cascaded H-bridge, power unbalance, overmodulation, third harmonic compensation

CLC Number:

TM464

ZHOU Jie, LI Ming, LI Liwei, YU Wenshan, LI Xueqing, YOU Rui. Research on Harmonic Compensation Strategy of Single-phase CHB Photovoltaic Grid-connected Inverter System[J]. Journal of Electrical Engineering, 2023, 18(2): 221-228.

Figures/Tables 18

References 20

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拟合系数	数值	拟合系数	数值
c₁	15 169	c₄	-184 620
c₂	-80 996	c₅	98 487
c₃	173 041	c₆	-21 835

参数	数值
最大功率/W	262.5
最大功率点电压/V	35
最大功率点电流/A	7.5
短路电流/A	8.2
开路电压/V	44.5

参数	数值
相电压幅值/V	110
滤波电感/mH	3
直流侧电容/mF	35
电网频率/Hz	50
载波频率/Hz	2 000
H桥模块数	4