Insulated Modular Auxiliary Power Source Concept with Multiple Outputs

Abstract

This paper presents an insulated auxiliary power source with multiple outputs based on a two-stage structure, where the first-stage operates as a controlled current source and the second-stage as an active rectifier. The second-stage is replicated for each load, where the output voltage is independently controlled by a hysteresis band controller integrated to the auxiliary power source's circuit. Insulation between the multiple stages is achieved by a medium-frequency transformer for each output. The main aim of this auxiliary power supply is to feed modular multilevel converters in laboratory applications that run at the lower range of medium-voltage dc. Theoretical analysis of the auxiliary power supply is presented and verified experimentally for the converter's two main modes of operation.

Keywords

• Auxiliary power source
• Modular Multilevel Converter
• Multiple-output