A discharge control apparatus for controlling a flyback power supply circuit which includes a transformer having a primary coil and a secondary coil and performing voltage conversion, and a driver for controlling energization of the primary coil. The power supply circuit supplies electric energy to a plasma reactor. The discharge control apparatus calculates, based on primary current flowing through the primary coil and primary voltage generated in the primary coil, supply energy supplied to the primary coil and regeneration energy which is a portion of the supply energy not used for the discharge in the plasma reactor. The discharge control apparatus controls the power supply circuit based on the calculated supply energy and the calculated regeneration energy. Also disclosed is a method for controlling the flyback power supply circuit.

Disclosed is a universal input voltage detection system for a flyback converter having a transformer coupled between an input and an output of the flyback converter. The transformer includes a primary winding coupled to the input of the flyback converter to receive an input voltage and a secondary winding coupled to the output of the flyback converter. The universal input voltage detection system comprises a controller, coupled to a switch, at a primary winding side of the transformer. The switch is coupled to the primary winding of the transformer and a current through the primary winding is generated when the switch is turned on. The controller is configured to operate in either continuous conduction mode (CCM) or discontinuous conduction mode (DCM) and indirectly detect the input voltage to the flyback converter based on the current through the primary winding generated while the switch is turned on.

A power conversion unit includes an input end to connect with a DC power supply, a first DC voltage end configured of a first terminal and a second terminal, a second DC voltage end configured of a third terminal and a fourth terminal, a converter, and a controller that controls the converter. The converter performs DC/DC conversion accompanied by power transmission between the input end and the first and second DC voltage ends. The controller generates a control command for the converter controlling a first voltage at the first DC voltage end and a second voltage at the second DC voltage end to a voltage target value.

A circuit structure of a voltage type single-stage multi-input low-frequency link inverter with an external parallel-timesharing select switch is formed by connecting a plurality of input filters connected to ground and a common output low-frequency isolation voltage-transformation filter circuit through a multi-input single-output high-frequency inverter circuit. Each input end of the multi-input single-output high-frequency inverter circuit is connected to an output end of each of the input filters in a manner of one-to-one correspondence. An output end of the multi-output single-input high-frequency inverter circuit and the output low-frequency isolation voltage-transformation filter circuit are connected. The multi-input single-output high-frequency inverter circuit includes an external multi-path parallel-timesharing select four-quadrant power switch circuit and a bidirectional power flow single-input single-output high-frequency inverter circuit successively connected in cascade.

A method and apparatus for providing welding type power includes a phase shifted double forward converter having a first and second converter with a controller and an output rectifier. The output rectifier has at least one cathode current path that creates a cathode magnetic field when current flows in the cathode current path. The output rectifier also has at least one anode current path that creates an anode magnetic field when current flows in the anode current path. The cathode current path is disposed and oriented and the anode current path is disposed and oriented such that the cathode magnetic field acts to at least partially cancel the anode magnetic field.

A power conversion device capable of suppressing current backflow while also improving current responsiveness and power conversion efficiency is achieved. A snubber capacitor capable of absorbing switching surge is connected to a low-voltage side switching circuit that includes switching elements. Until a predetermined time elapses from when a request to start switching is received, a controller determines that the snubber capacitor has not reached full charge or near-full charge, and asynchronously controls the low-voltage side switching circuit and a high-voltage side switching circuit that includes switching elements. After the predetermined time elapses, the controller synchronously controls the low-voltage side switching circuit and the high-voltage side switching circuit, and also controls a duty ratio of the low-voltage side switching circuit and the high-voltage side switching circuit such that current does not flow back from the low-voltage side switching circuit to the high-voltage side switching circuit.

A first full-bridge circuit, a transformer, a first reactor, a second full-bridge circuit, a second reactor, a capacitor, and a control unit are included. When activated, the control unit switches one or more of a combination of a first switching leg and a second switching leg and a combination of a third switching leg and a fourth switching leg with a certain second phase difference and drives first, third, fifth, and seventh switching devices or second, fourth, sixth, and eighth switching devices with a first duty ratio, which is lower than a duty ratio during normal operation.

A switch-mode power supply includes a pair of input terminals for receiving an alternating current (AC) or direct current (DC) voltage input from an input power source, a pair of output terminals for supplying a direct current (DC) voltage output to a load, and at least four switches coupled in a three-level LLC circuit arrangement between the pair of input terminals and the pair of output terminals. The power supply also includes a voltage doubler power factor correction (PFC) circuit coupled between the pair of input terminals and the three-level LLC circuit, and a control circuit coupled to operate the at least four switches to supply the DC voltage output to the load.

Technologies for controlling AC-to-DC converters are disclosed. In one illustrative embodiment, a controller of an AC-to-DC converter measures two voltage levels of a split voltage bus of a power factor correction (PFC) circuit. The controller controls current drawn from the positive and negative terminals of the PFC circuit by a DC-to-DC converter. By controlling the current drawn from the two terminals, the controller can control the voltages on the terminals to be equal (but opposite).

A switch-mode power supply includes a pair of input terminals for receiving an alternating current (AC) or direct current (DC) voltage input from an input power source, a pair of output terminals for supplying a direct current (DC) voltage output to a load, and at least four switches coupled in a three-level LLC circuit arrangement between the pair of input terminals and the pair of output terminals. The power supply also includes a voltage doubler power factor correction (PFC) circuit coupled between the pair of input terminals and the three-level LLC circuit, and a control circuit coupled to operate the at least four switches to supply the DC voltage output to the load.