Analog Regulation of Voltage from a Rectified High Voltage Source

Abstract:
Auxiliary power supplies (APS) form an integral part of power electronic systems in which the associated consumers have to be appropriately supplied. In this context, a voltage regulator (VR) circuit has been designed as a part of an APS, supplied from the drain-source voltage across a power semiconductor within a Modular Multilevel Converter (MMC) submodule (SM) [1], in order to achieve a high voltage (HV) DC output. In the hardware realization presented previously in [2], the duty cycle of the switching voltage was nearly 50%. By extension of the same operating principle, an investigation is carried out in this work for operation with unequal on- and off-periods of the input AC voltage, at different operating points of the circuit over a wider range of the input RC time constants and varying duty ratios. Relevant calculations and simulations have been verified in hardware for a maximum output power of 50W at 500 V DC, and presented in this paper.