A Hybrid Single-Phase Transformerless Solar Photovoltaic Grid-Connected Inverter With Reactive Power Capability and Reduced Leakage Current

Abstract

Among the renewable energy sources, photovoltaic (PV) solar power represents one of the most potential. The use of grid-integrated solar power is much more popular than off-grid systems. The total system cost and weight can be reduced by eliminating transformers for grid-tied applications. However, a leakage current with a high peak value flows across the system in the absence of galvanic isolation between an ac grid and PV. In addition, reactive power injection must be ensured in future grid-tied systems. In this paper, the authors have proposed a new hybrid topology using both decoupling and mid-point clamping techniques to reduce the root mean square (RMS) and peak value of leakage current. In addition, the proposed topology can provide both active and reactive power to the grid. The topology is simulated in the Matlab/Simulink environment for both the open loop and closed loop conditions and then validated through experiments. In the open loop conditions, leakage current issue has been addressed. In the closed loop conditions, active power (P) and reactive power (Q) are injected into the grid using model predictive control (MPC). Finally, a comparative analysis with other similar topologies has been performed.

Keywords

• Active power
• leakage current
• model predictive control
• reactive power
• total common mode voltage
• transformerless grid-tied inverter