A Novel Modular Multiport Converter for Enhancing the Performance of Photovoltaic-Battery Based Power Systems

This paper introduces a novel multiport power converter with modular architecture for photovoltaic (PV)-battery based power systems. Compared to conventional centralized multiport converters, the proposed converter significantly improves the utilization of PV available energy and battery capacity as it does not require a high number of series-connected PV and battery modules. The proposed converter also eliminates the need for additional battery cell/module equalizer circuitry by being able to implement directly energy management strategies that consider the different capabilities of battery modules to ensure charge/stress balancing. This makes it a promising solution for interfacing second-life batteries or for systems that utilize batteries with a high degree of mismatch. The modularity of the proposed converter enhances system reliability and fault tolerance and reduces the power/voltage ratings of the power electronic devices. The converter modes of operation, control strategy and design considerations are discussed. A 75 V/1 kW integrated PV-battery power system prototype is built and tested to validate the concept.