A voltage control apparatus includes a boost converter configured to convert an input voltage to a voltage equal to or higher than a first voltage in an operative state and directly output the input voltage in an inoperative state, a buck-boost converter coupled with the boost converter in parallel and configured to convert the input voltage to a second voltage lower than the first voltage, a memory, and a processor coupled to the memory and configured to keep the buck-boost converter in the operative state, set the boost converter to the inoperative state when the input voltage is equal to or higher than the first voltage, and change the boost converter to the operative state when the input voltage is lower than the first voltage.

Some embodiments of the invention include a pre-pulse switching system. The pre-pulsing switching system may include: a power source configured to provide a voltage greater than 100 V; a pre-pulse switch coupled with the power source and configured to provide a pre-pulse having a pulse width of T.sub.pp; and a main switch coupled with the power source and configured to provide a main pulse such that an output pulse comprises a single pulse with negligible ringing. The pre-pulse may be provided to a load by closing the pre-pulse switch while the main switch is open. The main pulse may be provided to the load by closing the main switch after a delay T.sub.delay after the pre-pulse switch has been opened.

A buck-boost power conversion circuit comprises a first active switch, a second active switch, an inductor, a center-tapped current transformation element, and a signal rectification unit. The first active switch is cascaded to the second active switch, which is connected in parallel with a power source. The inductor is connected with a capacitor. The center-tapped current transformation element includes a primary winding and a secondary winding. The primary winding are connected with the first and second active switches. The primary winding includes a tapped terminal connected with the inductor. While the first or second active switch is turned on, the primary winding supplies power to the inductor through the tapped terminal, and the secondary winding is induced magnetically to generate a magnetic induction signal. The signal rectification unit is connected with the secondary winding, receiving and rectifying the magnetic induction signal to generate a current sensation signal.

A device can include a first circuit configured to be exposed to a first environment, the first circuit comprising one or more first transfer inductors, and a second circuit isolated from the first circuit and configured to be exposed to a second environment, the second circuit comprising one or more second transfer inductors. The second environment can be a harsh environment. The first circuit and the second circuit can be wirelessly coupled via the one or more first transfer inductors and the one or more second transfer inductors to allow transfer of power and/or signals between the first circuit and the second circuit.

A power conversion apparatus is configured to supply a power to an auxiliary device provided in a vehicle, and the power conversion apparatus includes: a primary side circuit including a primary side port; a secondary side circuit including a plurality of secondary side ports and magnetically coupled with the primary side circuit via a transformer; a control unit configured to control a transmitted power that is transmitted between the primary side circuit and the secondary side circuit by changing a phase difference between a switching of the primary side circuit and a switching of the secondary side circuit; an inverter connected to a first secondary side port and supplying the power to the auxiliary device via the primary side port; and a charger connected to a second secondary side port and supplying the power to the auxiliary device via the primary side port.

An isolated power conversion apparatus has an isolation transformer, a series circuit including a load and an inductor connected in series with each other, the series circuit being disposed on a secondary side of the isolation transformer, and one or a plurality of switching means disposed between the series circuit and the secondary side of the isolation transformer, the switching means being bidirectional. This apparatus sends out power from a DC power supply of a primary side of the isolation transformer toward the load as DC power or AC power of an arbitrary polarity, or regenerates and supplies the DC power or AC power from the load to the DC power supply.

According to one aspect, embodiments herein provide an AC-DC converter comprising a rectifier, a capacitor, a DC bus coupled to the capacitor, a plurality of first switches coupled to the DC bus, a plurality of second switches coupled between the rectifier and the first switches, a transformer having a primary winding and a secondary winding, the primary winding coupled to the plurality of first switches, the plurality of second switches, and the rectifier, and the secondary winding coupled to an output, and a controller configured, in response to a determination that the input AC power is acceptable, to operate the plurality of second switches and the plurality of first switches such that output DC voltage is maintained at a desired output DC voltage level, and operate the plurality of first switches such that a DC bus voltage on the DC bus is maintained at a desired DC bus voltage level.

A non-contact power transmitting and receiving system includes an inverter configured to generate a high-frequency voltage, a voltage-current sensor configured to detect a phase difference between an output voltage and an output current of the inverter, a power transmission coil connected to the inverter, a power reception coil configured to receive electric power from the power transmission coil in a contactless manner, a rectifier circuit connected to the power reception coil, and a control unit configured to control the inverter and the rectifier circuit. The inverter includes arms. The rectifier circuit includes arms. The control unit adjusts at least one of switching timing of any arm of the inverter and switching timing of any arm of the rectifier circuit, in accordance with the phase difference detected by the voltage-current sensor.

A DC-to-DC converter includes a first DC side, a second DC side, a first capacitor, a first switch circuit, a magnetic element circuit, a second switch circuit, and a second capacitor. The DC-to-DC converter is adapted for converting between a first DC voltage and a second DC voltage. The magnetic element circuit is electrically coupled to the first switch circuit, and includes a plurality of magnetically coupled windings and an inductor. An oscillating current flowing in the first switch circuit is generated by controlling the first switch circuit and the second switch circuit, and an oscillating frequency of the oscillating current is determined by the capacitance of the first capacitor and the inductance of the inductor in the magnetic element circuit, and the first switch circuit and the second switch circuit are switched at a specific region of a wave trough of the oscillating current.

Resonant DC-DC converters use a switching network to step a single DC voltage up to a working DC level using a resonant tank. However, high voltage DC power supply systems, for example, those used to power X-ray sources, are increasingly being integrated into smaller form factors, and it is becoming attractive to be able to make use of multiple DC-DC power supplies to power such X-ray sources. The present invention provides a topology for a resonant DC-DC converter, a DC electrical supply system, and method of operating a DC-DC resonant converter. The proposed topology uses a switching network to connect multiple DC power supplies to the resonant tank, to enable a more flexible provision of input power.