A novel method of optimizing efficiency in hybrid photovoltaic-grid power system

In this paper, a method of optimizing efficiency of hybrid photovoltaic-grid power system by changing dc bus voltage is introduced. The hybrid photovoltaic-grid power system composed of a solar cell, grid, DC bus, solar cell interface converter (Boost + full-bridge LLC resonant converter), grid interface converter (single-phase PWM rectifier) and load interface converter (half-bridge LLC resonant converter). By analyzing the loss of every interface converters in hybrid photovoltaic-grid power system, the relationship between the bus voltage and the efficiency of the whole system can be found out. To verify the loss analysis and the efficiency optimization method, 1kW hybrid photovoltaic-grid power system hardware was built in the lab. The experimental results verify the feasibility of the efficiency optimization method.