The continuous effort to improve efficiency, reduce particle, and greenhouse gase emissions leads to the emergence of the concept “more electric.” This concept helps to boost the performance as well as the flexibility of the domestic and vehicular applications; however, on the other hand, it excessively burdens current power networks (including vehicle power systems). In order to remedy this problem, simultaneous usage of renewable sources and energy storages is encouraged. A multiconverter system is commonly adopted to process the renewable power in form of distributed generation. However, due to the discrete structure of such systems, power flow and load regulation are coordinated via communication channel, which inevitably reduces the reliability and dynamic response of the system. This paper presents the concept of multiport power electronic interface (MPEI) for renewable energy sources and storages. With a unified modular topology and highly integrated digital control system, controlled quasi-current source is achieved for each input port in both steady-state and transient power-sharing modes. MPEI analysis, modeling, design, and system operation are treated in a systematic manner in this paper. Both power stages and digital control system are implemented for a five-port MPEI. Experiments are conducted under meaningful operation scenarios. The results are presented to prove the feasibility of MPEI concept and system design methodology.

Fuel cells (FCs) are being considered as a potential alternative in long term to replace diesel/gasoline combustion engines in vehicles and emergency power sources. However, high cost and slow dynamic response of FC still persist as the main hurdles for wider applications. To remedy this problem, an energy storage system with adequate power capacity has to be incorporated. This paper presents a novel control design for FC-battery hybrid power system which enables both active current sharing and power source management control in such hybrid systems. Different hybrid power system structures are investigated and evaluated; dual-converter structure and four modes of operation are defined to provide efficient and sustainable solution to such a hybrid power system. A novel integrated control system with inherent current sharing and generation mode swapping capability is proposed; based on system component status, the control system is able to regulate the output power from each source under different scenarios. The dedicated control system is implemented in a TMS320F2812 DSP, and experimental results for an FC-battery-based uninterruptible power supply are provided to demonstrate the static and dynamic performance of the control system.