Fixed Frequency-Based Oscillation Mitigation Technique for Solid State Circuit Breaker in DC Microgrid Applications

This paper investigates instability issues in a 380V/20A Solid-State Circuit Breaker (SSCB) employing a variable frequency Pulse Width Modulation-Current Limiting (PWM-CL) technique. To enhance the SSCB's protection and to reduce the oscillatory nature of the SSCB, an improved Control Scheme is introduced with fixed frequency-based PWM-CL mode with an Artificial Ramp Compensation (ARC) technique. The proposed ARC control technique produces a Periodic Falling Slope Ramp Reference (PFSR) which eliminates the output oscillations and relationship between the PWM-CL time which in turn depends on the loading condition and perturbation. The effectiveness of the proposed control technique is validated through a 7.6KW SSCB integrated Buck Converter using MATLAB Simulink. The output response of the proposed control scheme illustrates the improvement in the operating condition of the buck converter during soft-start. Furthermore, it enhances differentiation between inrush and short circuit (SC) currents, leading to more accurate fault detection in the SSCB.