Output Voltage Regulation Technique Applied to an Unregulated Isolated DC-DC Converter for Wide Input Voltage Variations

This paper introduces a voltage regulation technique for an isolated power electronic converter that interconnects multiple transformers in series or parallel configurations using switches. This topology, known in the literature as Series-Parallel Auto Regulated Converter (SPARC), enables flexible reconfiguration to adapt to varying operating conditions. Unlike conventional control methods, the proposed approach dynamically adjusts both a control variable and the transformer configuration to enhance output voltage regulation accuracy. Simulation and experimental results, using a <inline-formula><tex-math notation="LaTeX">$500\ \rm{W}$</tex-math></inline-formula> prototype with an input voltage range from <inline-formula><tex-math notation="LaTeX">$50\ \rm{V}$</tex-math></inline-formula> to <inline-formula><tex-math notation="LaTeX">$150\ \rm{V}$</tex-math></inline-formula> and a regulated output voltage of <inline-formula><tex-math notation="LaTeX">$50\ \rm{V}$</tex-math></inline-formula>, confirm the effectiveness of the technique, demonstrating significant improvements in voltage regulation. The converter and the proposed regulation system efficiently manage wide input voltage variations while maintaining a stable output voltage.