A method may include detecting an output voltage of the output smoothing capacitor in the bridgeless interleaved power factor correction circuit of a critical mode, comparing the detected output voltage with a reference voltage, controlling the first and the second half-bridge circuits included in the bridgeless interleaved power factor correction circuit of the critical mode to be on and off based on an error signal between the output voltage and the predetermined reference voltage, measuring ON time of a synchronous rectification switch operation of the first half-bridge circuit by measuring a time period between OFF timing of an active switch of the first half-bridge circuit and output of a differentiation signal generated by a differentiation circuit included in the bridgeless interleaved power factor correction circuit of the critical mode; and assigning the measured time to next ON time of the synchronous rectification switch operation of the second half-bridge circuit.

A multi-port power conversion system can have a multi-winding transformer and at least three ports. Each port can be coupled to the multi-winding transformer. Each port can have a semiconductor bridge and a coupling network. For each port, the semiconductor bridge can have two or more levels and can comprise at least two switches. The coupling network for each port can comprise at least one inductor. The semiconductor bridge can be coupled to the multi-winding transformer via the respective coupling network. The multi-port power conversion system can have a multi-active bridge (MAB) architecture that is universally applicable to AC-DC, DC-DC, DC-AC, and AC-AC conversion applications and extendable to any number of ports.

Disclosed are three-phase system and distributed control method. The three-phase system comprises three-phase circuits, of which each phase circuit including at least one power conversion cell; and at least three phase controllers for controlling each phase circuit, respectively, each phase controller including a communication interface through which the at least three phase controllers are in communications connection with each other; wherein the phase controllers of each phase circuit is configured for regulating bridge arm voltages of the at least one power conversion cell in the phase circuit by receiving signals sent from the phase controllers of other two phase circuits through the communication interface. The three-phase system and the distributed control method of the invention solve problems of balance of three-phase current and stabilization of three-phase DC voltages by coordination among the three phases. Thanks to the invention, the three phases can be independently controlled to improve control flexibility.

Disclosed are three-phase system and distributed control method. The three-phase system comprises three-phase circuits, of which each phase circuit including at least one power conversion cell; and at least three phase controllers for controlling each phase circuit, respectively, each phase controller including a communication interface through which the at least three phase controllers are in communications connection with each other; wherein the phase controllers of each phase circuit is configured for regulating bridge arm voltages of the at least one power conversion cell in the phase circuit by receiving signals sent from the phase controllers of other two phase circuits through the communication interface. The three-phase system and the distributed control method of the invention solve problems of balance of three-phase current and stabilization of three-phase DC voltages by coordination among the three phases. Thanks to the invention, the three phases can be independently controlled to improve control flexibility.

Provided is a method for controlling a wind power installation. The wind power installation includes a generator for generating a generator current with one or more generator current phases, and an active rectifier for rectifying and controlling the generator current. For each generator current phase the rectifier has a plurality of controllable sub-rectifiers. Each controllable sub-rectifier is characterized by a partial inductance, each controllable sub-rectifier controls a partial current of the generator current phase and each generator current phase forms a summation current as a sum of all the partial currents of the relevant generator current phase. The active rectifier is controlled so that for each generator current phase the summation current is detected and each controllable sub-rectifier of the relevant current phase controls the partial current thereof depending on the detected summation current.

A power conversion apparatus employs multi-level techniques and wide band-gap semiconductor switching devices to achieve high efficiency in a converter system having high power density. The apparatus may be configured as a bi-directional conversion system capable of operating as both an inverter, configured to receive DC power and produce AC power, and as a rectifier configured to receive AC power and produce DC power. The apparatus is especially suitable for electric vehicle (EV) applications.

A converter assembly including a source connection system comprising a primary source connection, and at least one secondary source connection; a load connection system; a primary source converter including a primary rectifier connected electrically to the primary source connection, and having a boost topology, and a DC link connected electrically between the primary rectifier and the load connection system, the DC link including DC link capacitance; a secondary source converter, which is a direct-current converter having a boost topology, connected electrically between the at least one secondary source connection and the DC link; and a pre-charge converter adapted for pre-charging the DC link capacitance. The pre-charge converter includes a pre-charge direct-current converter having a step down topology.

An objective of the present application is to provide an apparatus for conversion between AC power and DC power. The apparatus includes a first power conversion circuit having a first AC side and a first DC side, at least one second power conversion circuit each having a second AC side and a second DC side; and at least one choke having a first terminal, a second terminal and at least one third terminal, wherein the first terminal is arranged to be electrically coupled to a phase of the AC power, and the second terminal and the at least one third terminal are electrically coupled to respective same phases of the first AC side of the first power conversion circuit and the second AC side of the at least one second power conversion circuit. Moreover, the choke includes a first common-mode choke and a first differential-mode choke, wherein: the first common-mode choke and the first differential-mode choke are electrically coupled in series via a first group of coil ends of the first common-mode choke and a first group of coil ends of the first differential-mode choke, and a second group of coil ends of one of the first common-mode choke and the first differential-mode choke are electrically coupled to the first terminal of the choke, and a second group of coil ends of the other are respectively electrically coupled to the second terminal and the at least one third terminal of the choke. The first common-mode choke can help provide high inductance to the high-frequency components of the common-mode current, which flows from the AC power source, since the impedance of the common-mode choke and the differential-mode choke depends on frequency on the same scale as inductance. The advantages of using the common-mode choke is that it provides twice the inductance of separate inductor design due to the coupling effect. Therefore it filters the common-mode current more effectively or the inductance size can be reduced for a given current ripple requirement.

Voltage converter circuits including a first and second branch. The first branch is coupled between a first DC terminal and a second DC terminal and includes a first and second winding around a magnetic core. The first and second winding are coupled to an AC terminal via a common node. The second branch is coupled in parallel to the first branch between the first and second DC terminals and includes a third winding around the magnetic core. The third winding is coupled to the AC terminal such that the first and second branches convert a first voltage into a second voltage. The first, second and third windings are configured to cause magnetic flux generated by a differential mode (DM) component of a first current in the first branch and magnetic flux generated by the DM component of a second current in the second branch to enhance with each other.

A system for controlling a plurality of power converters in a power system so as to turn each of the plurality of power converters into an ON state or an OFF state as a function of a sensed input power and a sensed output power such that one or more of the plurality of power converters in the ON state are operating in an optimal power efficiency range.