The present disclosure relates to a power factor correction circuit, a control method, and an electrical appliance. The power factor correction circuit may include: a power regulation branch, including a first switching unit, a second switching unit and a branch sampling resistor connected in series sequentially; an inductive branch, connected between an AC power source and a power regulation branch; a rectifier branch, including a first rectifier unit and a second rectifier unit, the rectifier branch may include a main line sampling resistor; a capacitance branch; a control circuit sampling a branch current flowing through each of the branch sampling resistors and a main line current flowing through the main line sampling resistor respectively, and controlling the switching of each power regulation branch sequentially. With the branch sampling resistor and the main line sampling resistor, the overall cost of the power factor correction circuit may be reduced.

Electrical systems for connecting rotary electric machines to dc networks operating at different voltages V and W where V>W are provided, along with gas turbine engine arrangements incorporating such systems.

In a power converter, a first single-phase AC conversion unit, which is connected to a first line of a first phase and a second line of a second phase of a first three-phase AC, a second single-phase AC conversion unit, which is connected to the second line of the second phase and a third line of a third phase of the first three-phase AC, and a third single-phase AC conversion unit, which is connected to the third line of the third phase and the first line of the first phase of the first three-phase AC, form a delta-connected load for an AC power supply system. At least the first single-phase AC conversion unit, the second single-phase AC conversion unit, and the third single-phase AC conversion unit form a first set in which respective output terminals are connected in series to one another, and the first set, and a second set and a third set, which are different from the first set, form each phase of a star connected power supply. A reactive power control unit controls a reactive power of a converter of each single-phase AC conversion unit based on a reactive power command value generated based on an acquired value related to an active power.

An energy storage device for a power system is provided. The energy storage device is electrically connected with a high voltage DC transmission grid. The energy storage device includes at least one energy storage element, at least one bidirectional inverter module, at least one medium frequency transformer and at least one bidirectional AC/DC conversion module. A DC terminal of each bidirectional inverter module is electrically connected with the corresponding energy storage element. A first transmission terminal of each medium frequency transformer is electrically connected with an AC terminal of the corresponding bidirectional inverter module. An AC terminal of each bidirectional AC/DC conversion module is electrically connected with a second transmission terminal of the corresponding medium frequency transformer. A DC terminal of each bidirectional AC/DC conversion module is electrically connected with the high voltage DC transmission grid.

A soft-switching, high-performance single-phase alternating current (AC)-direct current (DC) converter is provided. The AC-DC converter described herein provides a new circuit topology for single-stage, single-phase or multi-phase AC-DC power conversion with power factor correction (PFC) and galvanic isolation using a high-frequency isolation transformer. The AC-DC converter improves power conversion efficiency and power density—two of the most important metrics for a power converter. It achieves soft switching for high frequency switches in the circuit, leading to higher efficiency and lower electromagnetic interference (EMI).

This application discloses an apparatus, an inverter system, and a method for synchronizing carriers. The apparatus includes a modulation unit, a current processing unit, and a control unit. The control unit can adjust, based on a change trend between an amplitude of a first harmonic current and an amplitude of a second harmonic current and a change trend between a phase of a first carrier and a phase of a second carrier, a phase of an input carrier input into the modulation unit, to decrease an amplitude of a harmonic current output by an inverter and improve stability of a distributed power supply system. Further, a prior-art problem that impact of a harmonic current on a power supply system cannot be reduced by synchronizing carriers in a process of synchronizing carriers based on a zero sequence current is avoided, thereby improving the stability of the distributed power supply system.

This application discloses an apparatus, an inverter system, and a method for synchronizing carriers. The apparatus includes a modulation unit, a current processing unit, and a control unit. The control unit can adjust, based on a change trend between an amplitude of a first harmonic current and an amplitude of a second harmonic current and a change trend between a phase of a first carrier and a phase of a second carrier, a phase of an input carrier input into the modulation unit, to decrease an amplitude of a harmonic current output by an inverter and improve stability of a distributed power supply system. Further, a prior-art problem that impact of a harmonic current on a power supply system cannot be reduced by synchronizing carriers in a process of synchronizing carriers based on a zero sequence current is avoided, thereby improving the stability of the distributed power supply system.

A power conversion device connected in parallel to a second power conversion device including power conversion circuitry that performs power conversion by changing a connection state between first multiple lines on a primary side and second multiple lines on a secondary side, baseline selection circuitry that selects one of the second multiple lines on the secondary side as a baseline and partial modulation control circuitry that controls the power conversion circuitry to maintain a state in which the baseline is connected to one of the first multiple lines on the primary side and to change a connection state between other second multiple lines on the secondary side and the first multiple lines on the primary side, wherein the baseline selection circuitry switches a line selected as the baseline based on a switching timing used by second baseline selection circuitry of the second power conversion device to select a second baseline.

According to one aspect, embodiments of the invention provide an electrical-converter system comprising a printed circuit board including at least a first layer and a second layer, a switching node disposed on the second layer, a first transistor, a second transistor, a third transistor, and a fourth transistor disposed on the first layer, a first conduction path from a source of the first transistor, through the switching node, to a drain of the fourth transistor, the first conduction path having a first length, and a second conduction path from the source of the first transistor, through the switching node, to a drain of the second transistor, the second conduction path having a second length, wherein the first length of the first conduction path is greater than the second length of the second conduction path.

A multi-phase interleaved PFC converter includes at least six switches coupled in a multi-phase interleaved circuit arrangement, and a control circuit. The control circuit is configured to turn on and turn off a first one of the switches according to a PWM signal to operate the first switch as an active switch having an off-time as a function of a duty cycle of the PWM signal, while turning on and turning off a second one of the switches as a synchronous switch. The control circuit is also configured to receive signal(s) indicative of currents in each phase of the interleaved circuit arrangement, set an on-time of the second switch equal to the off-time of the first switch when the signal(s) indicate continuous mode operation, and set the on-time of the second switch to a duration less than the off-time of the first switch when the signal(s) indicate discontinuous mode operation.