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 densitytwo 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).

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.

A power supply apparatus includes converters connected in parallel to a three-phase alternating-current power supply, input current detectors that detect current flowing through the respective three phases of the three-phase alternating-current power supply, and load current detectors that detect load current of the converters. Each of the converters includes AC-DC converters inputs of connected to two of the three phases. The AC-DC converters are connected in parallel to each other using a common output. The AC-DC converters that are driven maintain balance of output current. A controller determines whether switching between a driven state and a stopped state of the respective AC-DC converters is performed based on detection results from the load current detectors and switches between the driven state and the stopped state of the respective multiple AC-DC converters based on detection results by the input current detectors.

A power supply apparatus includes converters connected in parallel to a three-phase alternating-current power supply, input current detectors that detect current flowing through the respective three phases of the three-phase alternating-current power supply, and load current detectors that detect load current of the converters. Each of the converters includes AC-DC converters inputs of connected to two of the three phases. The AC-DC converters are connected in parallel to each other using a common output. The AC-DC converters that are driven maintain balance of output current. A controller determines whether switching between a driven state and a stopped state of the respective AC-DC converters is performed based on detection results from the load current detectors and switches between the driven state and the stopped state of the respective multiple AC-DC converters based on detection results by the input current detectors.

An active rectifier includes first and second DC nodes, a switching circuit, and a controller configured to compute a voltage reference according to a load signal of the DC output, and a non-linear relationship between a load condition of the DC output and a DC bus voltage at the DC output, and to generate rectifier switching control signals according to the voltage reference to cause the switching circuit to convert AC input power from the AC input to control the DC bus voltage at the DC output.

An active rectifier includes first and second DC nodes, a switching circuit, and a controller configured to compute a voltage reference according to a load signal of the DC output, and a non-linear relationship between a load condition of the DC output and a DC bus voltage at the DC output, and to generate rectifier switching control signals according to the voltage reference to cause the switching circuit to convert AC input power from the AC input to control the DC bus voltage at the DC output.

An electrical power distribution system includes a number of alternating current (AC) power output ports to transmit electrical power at a first fixed AC voltage level to a corresponding number of AC power loads. An AC bus coupled to the AC power output ports, and to couple to an AC power grid, transmits electrical power at a second fixed AC voltage level. A DC bus transmits electrical power at a first fixed DC voltage level. A number of AC power input/output (I/O) adapters are coupled to the AC bus and the DC bus, each including a bidirectional AC-to-DC (AC/DC) converter to receive and convert the electrical power transmitted on the AC bus at the second fixed AC voltage level to the electrical power at the first fixed DC voltage level for transmission to the DC bus, and to receive and convert the electrical power transmitted on the DC bus at the first fixed DC voltage level to the electrical power at the second fixed AC voltage level for transmission to the AC bus. The system further includes logic coupled to the AC power I/O adapters, the AC power output ports, and the AC bus, to control an amount of the electrical power transmitted from the AC power grid to the DC bus and from the DC bus to the AC bus for transmission to the AC power grid and/or one or more of the AC power output ports.

An electrical power system connected to a power grid can include a generator having a stator and a rotor and a power converter. The stator is connected to the power grid via a stator power path. The power converter can include a line-side converter coupled to the power grid via a converter power path and a rotor-side converter coupled to a rotor bus of the rotor and the line-side converter via a DC link. The rotor-side converter is configured to convert a DC power on the DC link to an AC signal for the rotor bus. The power system can also include an active filter having one or more active controlled components. The active filter is coupled in parallel with the rotor-side converter to reduce harmonics of the electrical power system.

An electrical power system connected to a power grid can include a generator having a stator and a rotor and a power converter. The stator is connected to the power grid via a stator power path. The power converter can include a line-side converter coupled to the power grid via a converter power path and a rotor-side converter coupled to a rotor bus of the rotor and the line-side converter via a DC link. The rotor-side converter is configured to convert a DC power on the DC link to an AC signal for the rotor bus. The power system can also include an active filter having one or more active controlled components. The active filter is coupled in parallel with the rotor-side converter to reduce harmonics of the electrical power system.

The present invention relates to a method for reducing common mode current in power electronic equipment comprising two or more active front end (AFE) components (1) coupled in parallel between an AC supply grid (2) and a DC-link (3). A duty cycle of pulse width modulation (PWM) for the AFE components (1) is determined, and an error signal is derived based on the determined duty cycle of PWM and on a common mode current of the AFE components (1). A correction voltage is derived, based on the error signal, and a DC voltage control signal is derived based on the derived correction voltage and a measured DC voltage of the DC-link (3) and/or a DC voltage reference. The power electronic equipment is controlled in accordance with the derived DC voltage control signal. The present invention also relates to a method for starting active front end (AFE) components (1) of power electronic equipment comprising two or more AFE components (1) coupled in parallel between an AC supply grid (2) and a DC-link (3).