Optimization of Reactive Power Distribution in Series PV-Battery-Hybrid Systems

Series topologies have been gaining interest in photovoltaic-battery-hybrid (PVBH) applications. In previous research, the reactive power contribution from PVBH systems is distributed in a way to maintain the apparent power of all converters at the same level. However, the prior-art strategies cannot ensure optimal reactive power distribution, as the calculated reactive power references are not the analytical optimal solutions. In most cases, the apparent power of certain converters can be higher than others. This will lead to the overloading of certain converters and even the power curtailment of PV converters in extreme cases. To improve the performance of the reactive power distribution, an optimized reactive power distribution method based on the particle swarm optimization (PSO) algorithm is proposed in this paper. By doing so, the optimal reactive power reference for each converter can be obtained, and thus, preventing the potential overloading of certain converters. Experimental results have validated the effectiveness of the proposed solution.