Abstract: Methods and systems for controlling an output voltage of a resonant converter during a light load condition. One such method includes generating a normalised conduction time of the resonant converter that varies inversely with a switching frequency of the resonant converter by continuing to operate the resonant converter in a Pulse Frequency Modulation mode at a low switching frequency that is similar to the resonant frequency. The method also includes controlling a power level delivered to a secondary winding of a transformer positioned between a resonant tank and an output rectifier of the resonant converter by regulating the normalised conduction time, where the delivered power level is variable based on load conditions. The method further includes generating an output voltage using the output rectifier wherein the magnitude of the output voltage corresponds to the power level delivered to the secondary winding.

Abstract: A method is provided for operating a resonant power conversion apparatus The method may include charging a capacitor connected to a power source in parallel, and determining a discharge time point and a discharge period of a discharge circuit, where the discharge circuit includes a resistor and a switch connected in series and is connected to the capacitor in parallel. The method may also include outputting, by a switch control circuit, a switch control signal by determining the switch control signal based on the discharge time point and the discharge period, and discharging the charged capacitor through the resistor based on the switch control signal applied to the switch. A resonant power conversion apparatus for performing the above-described method is provided.

Abstract: Various embodiments include a modular multilevel converter comprising: two phase units in parallel each with an upper arm and a lower arm, each arm with cells in series, each cell with an energy storage element and switching the element in or out of the series of cells; a control unit for the switches; a middle converter arm in series between the upper and lower arm, with cells arranged in series; an upper node between the upper and middle arms and a lower node between the lower and middle arms; an upper bridging element arranged between said upper node and an AC terminal; and a lower bridging element arranged between said lower node and said AC terminal.

Abstract: In the present uninterruptible power supply apparatus (U1), in a power failure of a commercial AC power supply (41), a switch (1) is turned off to electrically cut off the commercial AC power supply (41) from an AC input filter (2), and when DC voltage (?E=Ep?En) that is the difference between terminal-to-terminal voltages (Ep, En) of first and second capacitors (C1, C2) exceeds a threshold voltage (ETH), first and second IGBT devices (Q1, Q2) or third and fourth IGBT devices (Q3, Q4) included in the converter (3) are turned on and off to reduce DC voltage (?E).

Abstract: An apparatus including direct-current (DC)-alternating-current (AC) inverter circuitry, first and second circuits, and output circuitry. The DC-AC inverter circuitry inverts a DC input signal corresponding to an input voltage to an AC signal. The first circuit and second circuits respectively include inductive isolation circuits driven in response to power from the at least one AC signal, and rectifier circuits that responds to the inductive isolation circuits by outputting first and second rectified signals, where at least one of the first and second rectifier circuits characterized as being limited by a voltage breakdown rating. The output circuitry provides a DC output voltage signal and to cascade a plurality of signals, including the first and second rectified signals, to provide a voltage source that is dependent on the first and second rectified signals and greater than voltage breakdown rating.

Abstract: A bipolar current control drive circuit for an inductive load includes a switching power supply circuit in which an alternating current from a power supply is formed to a direct current smoothed through a rectifier bridge diode and a primary smoothing capacitor, the current is transmitted to a secondary side using a switching transformer, and the current is formed to a direct current. The switching transformer includes a first secondary coil and a second secondary coil for one primary coil to form alternating currents from the secondary coils to direct currents in reverse orientations and output the currents to an inductive load. A polarity control circuit controls switching between closing and opening of a first secondary switching element and a second secondary switching element and controls the polarity of an electric current.

Abstract: A power supply is provided. The power supply includes: a switching module including switching elements and is configured to receive rectified power; a transformer configured to transform first power received from the switching module; an outputter including first and second switching elements, and is configured to receive the transformed first power from the transformer and output an output voltage that follows a preset reference voltage; and a controller configured to control the switching module to operate in a full bridge mode or a half bridge module based on a peak voltage of the rectified power, adjust a switching frequency of the switching module based on the output voltage, control switching of the first and second switching elements based on the output voltage, and adjust a duty ratio of each of the first and second switching elements based on the rectified power.

Abstract: A power conversion device includes a transformer, a plurality of converter cells, and a control circuit that controls semiconductor switching elements in each of the converter cells to be turned on and off. The transformer includes: a primary winding group being connected in multiple phases to an AC power supply including multiple phases; and a plurality of secondary winding groups. Each secondary winding group includes, in each of the multiple phases, secondary windings each formed of a single-phase open winding. Each converter cell converts a single-phase AC voltage between AC nodes connected to the respective secondary windings into a DC voltage by control of the semiconductor switching elements to be turned on and off, and outputs the converted DC voltage between a pair of DC nodes. The DC nodes of the plurality of converter cells are connected in series between a first DC terminal and a second DC terminal.

Abstract: An apparatus for processing electric power includes a power-converter having a path for power flow between first and second power-converter terminals. During operation the first and second power-converter terminals are maintained at respective first and second voltages. Two regulating-circuits and a switching network are disposed on the path. The first regulating-circuit includes a magnetic-storage element and a first-regulating-circuit terminal. The second regulating-circuit includes a second-regulating-circuit terminal. The first-regulating-circuit terminal is connected to the first switching-network-terminal and the second-regulating-circuit terminal is connected to the second switching-network-terminal. The switching network is transitions between a first switch-configuration and a second switch-configuration. In the first switch-configuration, charge accumulates in the first charge-storage-element at a first rate.

Abstract: A direct-current (DC) voltage conversion device includes a resonate driving device, at least two second transformers, at least two second transformers, at least two third transformers, and a rectifying device. The primary sides of the second transformers are connected in series via a first conductive wire and coupled to the resonate driving device via a second conductive wire. The primary sides of the second transformers are connected in series via a third conductive wire and coupled to the resonate driving device via a fourth conductive wire. The primary sides of the third transformers are connected in series via a fifth conductive wire and coupled to the resonate driving device via a sixth conductive wire. The rectifying device is coupled to the secondary sides of the transformers.

Abstract: An AC-DC converter with synchronous rectifier (SR) architecture and method for operating the same are described. Generally, a secondary side integrated circuit (IC controller of the AC-DC converter includes a peak-detector block coupled to detect peak voltages sensed on a SR-SNS pin. The peak-detector block comprises a peak comparator, a sample-and-hold (S/H) circuit, and a DC offset circuit. The peak comparator is coupled to receive a sinusoidal input from the SR-SNS pin. The S/H circuit is coupled to sample the sinusoidal input and to provide a peak sampled voltage. The DC offset voltage circuit is coupled between the output of the S/H circuit and a reference voltage input of the peak comparator to subtract a DC offset voltage from the peak sampled voltage.

Abstract: A power converter includes at least three booster modules for transferring power at least from an AC input side to a DC output side. Each booster module has a galvanically separated input and output, and can be operated as a power factor correction module. The input of a first booster module is connected to the input side, and its output is connected to the output side for providing a first output current to the output side. The input of a second booster module is connected to the input side, and its output is connected to a buffer capacitor for providing a second output current to the buffer capacitor. The input of a third booster module is connected to the buffer capacitor and its output is connected to the output side for providing a third output current to the output side.

Abstract: A related power conversion circuit includes a three-level switch circuit and a resonant circuit, and a control method of the related power conversion circuit includes: controlling all transistors in the three-level switch circuit to be turned off, where a body diode connected in parallel to a transistor S1, a body diode connected in parallel to a transistor Q1, and a body diode connected in parallel to a transistor Q2 are all turned on based on a current freewheeling function of the resonant circuit; controlling the S1 to be turned on, to set up a first working state of the power conversion circuit; and after the first working state lasts for a time length T1, controlling the Q1 and the Q2 to be turned on.

Abstract: A power conversion device includes a converter, a first capacitor, and a second capacitor. The first capacitor is connected between a DC positive bus and a DC neutral point bus. The second capacitor is connected between the DC neutral point bus and a DC negative bus. The converter includes a diode rectifier connected between an AC power supply and each of the DC positive bus and the DC negative bus, and a first AC switch electrically connected between the AC power supply and the DC neutral point bus. The power conversion device further includes a first fuse electrically connected between the first AC switch and a connection point between the first and second capacitors.

Abstract: An example system includes an input voltage terminal; a power converter integrated circuit (IC) package fuselessly coupled to the input voltage terminal and having first and second pins, the power converter IC package configured to detect a short between the first and second pins; and a load circuit coupled to the power converter IC package.

Abstract: A high-frequency resonant power conversion system for transferring power from an oscillator to a load or vice-versa, the system including components with at least one fluctuating parameter and is configured to control the value of a defined variable selected from: a certain current, a certain voltage, a phase difference between a certain voltage and a certain current, and a certain power; the system further including a virtual impedance creation loop which is configured to create a virtual component, the virtual component forming a basis for changing amplitude and a phase of the oscillator, thereby to compensate for a deviation from the controlled variable due to the fluctuations.

Abstract: A power converter, such as a flyback power converter, configured to send digital information from a secondary side to a primary side of the power converter and notify the secondary side that the communication has been received by the primary side. In this manner the secondary side may receive an acknowledgement (ACK) from the primary side, while maintaining isolation between the primary side and secondary side. To implement the ACK response to digital communication from the secondary side, the primary side may delay generating a PWM pulse to the primary side switch. The secondary side may detect the missing PWM pulse based on a change in the integrated secondary side current and determine that the primary side has sent an ACK response.

Abstract: In a control apparatus for a power converter, a current obtainer obtains a current flowing through an inductor as an inductor current, and an alternating-current voltage obtainer obtains an alternating-current voltage. A drive signal outputting unit generates, based on the alternating-current voltage obtained by the voltage obtainer, a sinusoidal command. The drive signal outputting unit performs peak-current mode control to output a drive signal that controls switching of the drive switch to thereby cause the inductor current to follow the sinusoidal command. A delay unit delays, for one switching cycle of the drive switch, an off-switching timing of the drive switch in accordance with the alternating-current voltage. The drive signal defines the off-switching timing of the switch.

Abstract: A transformer includes a magnetic core, a primary side winding and a plurality of secondary side windings. The magnetic core includes a first outer column, a second outer column, an upper cover and a lower cover. The first outer column and the second outer column are disposed between the upper cover and the lower cover. The primary side winding is disposed on the first outer column and the second outer column, and the plurality of secondary side windings are disposed on the first outer column and the second outer column. Each of the secondary windings has one end passing through a region between the first outer column and the second outer column.

Abstract: A power converter includes a full-bridge conversion circuit. The full-bridge conversion circuit includes a first leg and a second leg. The first leg includes at least two switches coupled to each other at a first node, and the second leg includes at least two switches coupled to each other at a second node. The power converter further includes an AC filter. The AC filter includes a first inductor, a second inductor and a capacitor. The first inductor includes a first end coupled to the first node and a second end could be couple to a grid. The second inductor includes a first end coupled to the second node and a second end could be couple to the grid. The capacitor includes a first end coupled to the second end of the first inductor and a second end coupled to the second leg. The first end of the capacitor is electrically coupled to the second end of the first inductor during a cycle of an AC voltage of the grid.