A power supply device is presented. The power supply device includes a voltage conversion unit. The voltage conversion unit includes a capacitor divider circuit. The capacitor divider circuit includes a plurality of capacitors coupled to each other in series. Further, the voltage conversion unit includes a step-down transformer coupled to at least one of the plurality of capacitors. The power supply device also includes a low pass filter configured to be coupled to at least one high voltage power line and the voltage conversion unit, where the low pass filter is configured to provide filtered power to the voltage conversion unit.