Research on Energy Management of 500W Solid Oxide Fuel Cell Hybrid Power System

Abstract

For the feature of Solid Oxide Fuel Cell (SOFC) is low output voltage, large current range and slow dynamic response, this paper regards lithium battery as an auxiliary energy storage device to solve abrupt change of load power, and further designs an energy management system to ensure the safety and stability of SOFC system. Firstly, a 500W crossflow stack model is built in this paper. Then, based on the characteristics of charge and discharge response as well as the experimental data of lithium batteries, a second-order RC equivalent circuit model based on current direction is built. Thirdly, using SOFC stack to output average power and lithium battery to release or absorb sudden power mutation of load as the basic strategy, the thermoelectric cooperative control algorithm of SOFC side and lithium battery side are designed respectively. Finally, a controller model based on the energy management strategy designed in this paper is built and simulated in Matlab/Simulink environment. It is proved that the control strategy designed in this paper could realize the rapidity of load tracking and the controllability of lithium battery SOC under the condition of satisfying the temperature constraints of the stack. At the same time, fuel starvation can be avoided and the system efficiency can be effectively improved.