In a start-up control in which primary-side direct-current (DC) terminals and secondary-side DC terminals are charged by an external power supply outside a power conversion device, initially, one-side DC terminals are charged by the external power supply while switching operations of the primary-side bridge circuit and the secondary-side bridge circuit are stopped. Subsequently, a bridge circuit that is connected to the DC terminals not charged by the external power supply stops the switching operation and operates in a diode rectifying mode, while a bridge circuit that is connected to the DC terminals charged by the external power supply performs the switching operation and outputs an AC voltage whose voltage pulse width has been subjected to a variable control so that the voltage pulse width is smaller for a greater voltage difference of the charged DC terminals from the uncharged DC terminals.

A DAB converter that is capable of inhibiting a decrease in the transmission efficiency of electric power due to an individual difference of the inductance. A DAB converter including: a transformer having a primary-side winding and a secondary-side winding; a first and second full bridge circuit; a first and second capacitor; and a control unit, in which, the primary and secondary side winding is connected between a midpoint and a midpoint of the first full bridge circuit, the first capacitor is connected between two input/output terminals included in the first full bridge circuit, the second capacitor is connected between two input/output terminals included in the second full bridge circuit, and the control unit configured to adjust a phase difference between the switching of the first and second full bridge circuit based on an estimated value of an inductance of the DAB converter.

The present disclosure relates to an electric vehicle fast charger, and provides a high-efficiency, low-cost electric vehicle fast charger by controlling a charging current and voltage using a simple non-isolated dc/dc converter after rectifying an output of a high voltage distribution transformer.

Various embodiments of the present disclosure relate to power conversion using a planar transformer assembly that provides medium-voltage isolation at high frequencies. A planar transformer comprises primary and secondary planar windings configured to generate an isolated output. Each primary and secondary winding is interleaved on layers of a printed circuit board using one or more vias within the layers of the printed circuit board. The planar transformer also comprises a magnetic core and a field-shaping apparatus coupled with the printed circuit board. The field-shaping apparatus is configured to shape an electric field generated by the windings. The primary windings can be coupled to a DC source via switching devices while the secondary windings can be coupled via switching devices to one or more DC ports followed by AC inverters configured to generate three single-phase AC outputs for medium voltage applications.

A voltage converter, including an input adapted to couple to a voltage source and a transformer including a primary coil and a secondary coil. Primary side circuitry, including a first switching circuit, is coupled to the primary coil. A second switching circuit is coupled between a first terminal and a second terminal of the secondary coil, and configured to selectively close to short circuit the first terminal to the second terminal.

Systems and methods for controlling a dual active bridge converter are disclosed herein. An output voltage of a dual active bridge converter is sensed. Based at least in part on the output voltage, a target intra-bridge phase shift amount between two bridges of the dual active bridge converter is computed. A plurality of switch control signals, which are provided to respective switches of the dual active bridge converter, are caused to switch according to a time-based switching sequence based on the target intra-bridge phase shift amount to compensate for variations in the output voltage.

An output terminal of a contact type charger connected to an AC power supply 1 and being for boosting or stepping down an input voltage, and an output terminal of a non-contact type charger for receiving power in a non-contact manner are connected to an input terminal of a DC/DC converter via an integrated bus, a DC link capacitor is connected between an AC/DC converter and an isolated DC/DC converter included in the contact type charger, an integrated capacitor is connected to the integrated bus, and a control circuit adjusts a DC voltage of the DC link capacitor or the integrated capacitor such that at least one of power losses or a total power loss of the contact type charger, the non-contact type charger, and the DC/DC converter is reduced.

In a DC/DC converter, in first power transmission in which power is transmitted from a first DC power source to a second DC power source, on/off drive of a positive electrode-side switching element and a negative electrode-side switching element is stopped in a third bridge circuit on the power-receiving side. When a power transmission amount by the first power transmission is smaller than a first reference value, a control circuit lowers the switching frequency of the switching elements of a first bridge circuit and a second bridge circuit on the power-transmitting side and a fourth bridge circuit on the power-receiving side, compared with when the power transmission amount is equal to or greater than the first reference value.

A synchronous average harmonic current controller for a line connected bidirectional resonant power converter results in a harmonic voltage gain closely related to the commanded bridge duty cycles. A primary bridge has its duty cycle set to achieve controlled line power transfer and voltage regulation of a primary bus energy storage capacitor. A secondary bridge circuit has its duty cycle set to achieve voltage regulation of secondary bus energy storage capacitor. A first embodiment uses the independent energy storage elements to achieve power factor correction and low noise regulation using a single stage. A second embodiment uses feedforward duty cycle control to achieve isolated voltage regulation using the well-defined voltage gain resulting from the synchronous average harmonic current controller.

A power supply system 1 includes: a variable voltage power supply 7 that outputs power of a variable voltage from a pair of secondary-side input/output terminals 72p and 72n; and power lines 21 and 22 that connect the pair of secondary-side input/output terminals 72p and 72n and a load 4. The first power line 21 is provided with a first switch unit 31 and a third power line 23 that connects both ends of the first switch unit 31, and the third power line 23 is provided with a third switch unit 33, a DC power supply 30, and a second switch unit 32 in series. The fourth power line 24 connects the third power line 23 and the second power line 22. The fourth power line 24 is provided with a fourth diode 34a that allows an output current of the DC power supply 30.