Sliding Mode Control of a Hybrid Fuel cell-Battery Power System

This paper presents the analysis and design of sliding mode control (SMC) for a hybrid power system, which consists of a fuel cell, a battery, a unidirectional converter, and a bidirectional converter. The fuel cell and the battery are connected to the same voltage bus through a unidirectional converter and bidirectional converter, respectively. Fuel cell has a slow start and a large time delay to respond the transient. Therefore, the battery as an auxiliary energy source provides the power during the system’s start and absorbs the dynamic power when the load varies. A SMC is proposed to control a unidirectional converter for fuel cell and a bidirectional dc/dc converter for a battery. The SMC used in the paper has a capability of robustness to control properly under all operating conditions.