Harmonic Mitigation in Single-Phase H-Bridge Inverter Based on the DC Side Current DFT Analysis

In single-phase power inverter systems, when the load is nonlinear, output current will contain various harmonic currents. DC-side current will be disturbed by various harmonic currents at the AC-side. It is very harmful for the security, stability and reliability of the system. Power decoupling module compensating for the pulsation power has only been discussed in some papers in theory. However, these methods are difficult to be used in the actual circuits. In this paper, a novel power decoupling method of power-decoupling by applying Discrete Fourier Transform (DFT) is proposed to analyze the DC-side current real-timely. Various harmonic currents can be mitigated respectively with the appropriate control of capacitor voltage. To prove the correctness and feasibility, a simulation model of the H-bridge inverter based on the power-decoupling module has been established.