Digital Sliding Mode Current Control with Fixed-Frequency PWM of Bidirectional DC/DC Converter for Residential DC Microgrid

The bidirectional DC/DC converter is popularly employed for battery charging and discharging in the residential DC microgrid. However, its reference current has a wide range which is not a trivial matter for the linear control. In this paper, the digital sliding mode control with fixed-frequency pulse width modulation is proposed for the current control loop to obtain tracking performance and robustness. The simulation results of a bidirectional DC/DC converter indicate that the inductor current tracks well not only a step reference current but also a reference current containing a triangular waveform or a sinusoidal waveform. Besides, the simulation results also confirm that the current control loop has the robustness against the variation of input voltage and DC-bus resistance.