A Low Complexity Control System for a Hybrid DC Power Source Based on Ultracapacitor–Lead–Acid Battery Configuration

A dc hybrid power source based on the combination of ultracapacitor and lead–acid battery is considered in this paper. The various control systems for such hybrid power source reported in the technical literature thus far are rather complex. A low complexity control system for such hybrid power source is proposed in this paper. The key feature of the proposed control system is its capability to maintain operation of the hybrid power source within all important operational limits. The proposed control system allows one to allocate the high-frequency current demands to the ultracapacitor and specify the current limits for both the battery and the ultracapacitor. It also maintains operation of the battery within its state of charge limits and the ultracapacitor voltage at a predefined value while charging the ultracapacitor from the battery rather than from the common dc bus. Presented experimental results verify the satisfactory operation of the power source utilizing the proposed control system.