A DC-DC converter is operated in a boost mode by operating a plurality of low-voltage side switches with a first fixed duty cycle (greater than 0.5), with cutting off a plurality of the first high-voltage side switches and a plurality of the second high-voltage side switches, with conducting a plurality of the first diodes of the first high-voltage side switches and a plurality of the second diodes of the second high-voltage side switches, and with alternatively conducting and cutting off a bidirectional switch. In a buck mode, the low-voltage side switches are cut off and a plurality of diodes of the low-voltage side switches are conducted. Furthermore, the first high-voltage side switches are complemented and are operated with a second fixed duty cycle (less than 0.5) while the second high-voltage side switches are conducted and cut off alternatively and the bidirectional switch is switched on and off.

A power converter controller includes a primary controller coupled to operate in a first mode to control a power switch with a primary switching pattern. A secondary controller is galvanically isolated from the primary controller. The secondary controller is coupled to initiate a transition operation with the primary controller to take control of the power switch with one or more control signals through a communication link. The primary controller is coupled to acknowledge receipt of the one or more control signals to the secondary controller and transition from the first mode to a second mode.

Various embodiments relate to a power converter including a resonant converter with an controller, the controller configured to control the converter to operate in a normal mode when output power is above a burst mode threshold level, start a timer when the output power falls below the burst mode threshold level, continue operating in the normal mode until the timer reaches a predetermined time and operate in burst mode when the timer reaches the predetermined time.

Provided is a DC power supply device If an electrical tool (81) of a rated voltage of 36 V is connected to the DC power supply device (1) (if the voltage of a lower positive terminal indicates the presence of a short bar), a microcomputer (30) performs control so as to switch a switching element (Q1) on and output a DC voltage of 36 V between an upper positive terminal and the upper negative terminal. If an electrical tool (81) of a rated voltage of 18 V is connected to the DC power supply device (1) (if the voltage of the lower positive terminal indicates the absence of a short bar), the microcomputer (30) performs control so as to switch a switching element (Q2) on and output a DC voltage of 18 V between the upper positive terminal and the upper negative terminal.

Controlling switching frequency of a switching power converter. At least some example embodiments are methods of operating a switching power converters, comprising: operating, by a primary-side controller, a switching power converter at a first frequency set by a resistor coupled to a first pin of the primary-side controller; and sensing a synchronization signal applied to the first terminal of the primary-side controller, the synchronization signal has a second frequency that is variable; and operating, by the primary-side controller, the switching power converter at the second frequency.

Embodiments described herein relate to a driving circuit, comprising: a rectification stage configured to convert an AC input to a rectified AC output; a transmitter coil; and an inverter directly coupled to the rectification stage. The rectified AC output from the rectification stage is fed directly to the inverter and the inverter is configured to convert the rectified AC output from the rectifier to an AC output for the transmitter coil.

The present disclosure provides a forward converter with secondary LCD connected in series to realize excitation energy transfer, comprising a forward converter main circuit and an energy transfer and transmission circuit. The forward converter main circuit includes a high-frequency transformer T, a switching tube S, a diode D1, a diode D2, an inductance L1, and a capacitor C1. The energy transfer and transmission circuit includes a diode D3, a capacitor C2, and an inductance L2. The circuit structure of the present disclosure has simple circuit structure and high reliability. And the reverse recovery problem of the diode could be eliminated by the soft switch-off or soft switch-on of the switching tube, which further reducing the loss of switching tube and diodes and improving the overall efficiency. In addition, the excitation energy could be transferred to the load side to improve the energy transmission efficiency.

The present disclosure provides a forward converter with secondary LCD connected in parallel to realize forward and backward energy transmission, comprising a forward converter main circuit and an energy transfer and transmission circuit. The forward converter main circuit includes a high-frequency transformer T, a switching tube S, a diode D1, a diode D2, an inductance L1, and a capacitor C1. The energy transfer and transmission circuit includes a diode D3, a capacitor C2 and an inductance L2.

A control circuit for a switching converter having a main power switch and an auxiliary power switch, where the control circuit is configured to: charge and discharge a junction capacitor of the main power switch during a turn-off period of the main power switch; and adjust a conduction time of the auxiliary power switch according to a difference between the charged and discharged charge levels across the junction capacitor.

The present invention concerns a node of an HVDC grid composed of HVDC nodes and of a plurality of links interconnecting the HVDC nodes, each HVDC node being interconnected to at least one HVDC node of the HVDC grid by a link composed of conductive cables for high voltage direct current transportation and one optical fiber, at least one HVDC node being interconnected to at least two HVDC nodes, each HVDC node comprising, for each link connecting the HVDC node to the at least one other HVDC node, a link module comprising a fault sensing device, a breaker, and an optical transceiver for communicating through the optical fiber of the link.