Analysis and control of boost inverter for fuel cell applications

Alternative energy systems (AES) are becoming popular for small scale power generation. Designing the converters which transform the DC power into AC is the main development area of AES. Conventional single-phase voltage source inverter (VSI) uses buck topology which gives lower average output voltage than the input DC voltage. However, where the output voltage requirement is larger than the input DC voltage, such as uninterruptible power supply, fuel cell (FC) and photovoltaic systems, boost inverters are used. The boost inverter applied in this study consists of two boost DC-DC converters, which provides sinusoidal AC voltage output. The key drawback of the inverter lies in its control structure. In this paper, a dual loop control method is applied to ensure pure sinusoidal output voltage with fast dynamic response and low input current ripple. The input voltage of the inverter is assumed to be stable at 48 V considering commercially available FC voltage and the output voltage is regulated at 110 Vrms. In this article, the operating principle, mathematical modelling, analysis and control strategy of the boost inverter is presented. The proposed control strategy is verified with simulation using MATLAB/Simulink®. Simulation results show that the output voltage is 110 Vrms pure sinusoidal and the input current has low ripples.