A power supplying apparatus includes a first piezoelectric transformer operated at a first operating frequency, a second piezoelectric transformer operated alternately with the first piezoelectric transformer and operated at a second operating frequency, wherein the second operating frequency is a multiple of the first operating frequency.

An embodiment of the invention discloses a method for powering down a power converter with a photo coupler. Responsive to disconnection of a load from the power converter, the power converter is placed into a standby mode, during which a LED current flowing through the LED of the photo coupler is switched a predetermined number of times at each predetermined period, where the predetermined number is at least once.

An electric power converter, in particular for MVAC/LVAC to LVDC electric power conversion drives, including an active front end AFE, a transformer and an LCL-filter with a grid side choke and a drive side choke. According to the disclosure, the transformer and the LCL-filter are at least partially magnetically combined with each other.

Embodiments of the disclosure provide an electric power distribution (EPD) system that includes a first conversion module electronically connected between a voltage source and a bus. The first conversion module includes a transformer system electronically connected to a first converter circuit having a first maximum voltage rating. The voltage source provides a voltage source output, and the first maximum voltage rating is less than the voltage source output.

An apparatus includes a primary transformer circuit including a plurality of primary coils. The apparatus further includes a delta secondary transformer circuit configured to magnetically couple to the primary transformer circuit. The delta secondary transformer circuit includes a first plurality of secondary coils, a first plurality of nodes coupled to the first plurality of secondary coils, and a second plurality of secondary coils configured to magnetically couple to the plurality of primary coils. Each coil of the second plurality of secondary coils is physically coupled to a respective node of the first plurality of nodes.

An energy conversion device with an integrated active cell balancing circuit. The energy conversion device comprising a cell balancing circuit adapted to be connected to a plurality of cells of a battery, where the cell balancing circuit forms a DC bridge. A transformer, having a primary winding forming a portion of the cell balancing circuit, couples energy to a secondary winding. The secondary winding forms a portion of a resonant cycloconverter configured to convert the coupled energy to an AC output.