A Simplified Power Balance Strategy for Three-Phase Cascaded H-bridge Photovoltaic Inverter

In order to solve the inter-phase power imbalance problem for three-phase cascaded H-bridge (CHB) photovoltaic (PV) inverters, this paper proposes a simplified power balance strategy based on zero sequence voltage (ZSV) injection. Compared with the conventional methods, proposed ZSV can be obtained simply by vector composition without calculating its amplitude and phase angle, respectively. It avoids complex calculation process effectively which includes the solution of the inverse trigonometric functions and root square operation. Moreover, the proposed method can be easily extended to the non-unity power factor condition. The validity and effectiveness of the proposed strategy are verified both by simulation and experimental results.