A power supply circuit includes at least two input terminals that receive an input voltage, a transformer including a primary side electrically connected to the input voltage, a rectifier electrically connected to a secondary side of the transformer, and a boost switch electrically connected in parallel with the rectifier and a pair of output voltage terminals that include a first output voltage terminal and a second output voltage terminal. The input voltage is electrically connected to an AC source, and each of the at least two input terminals receives a different phase of the AC source.

A matrix power conversion device including a plurality of three-phase switching modules and a controller is provided. Each three-phase switching module includes a plurality of bidirectional switches connected to the input phase voltages of the three-phase input power respectively and outputs a corresponding output phase voltage of the three-phase output power. The controller determines a maximum voltage, an intermediate voltage and a minimum voltage among all the input phase voltages to acquire a waveform of a control carrier wave in a switching cycle. The controller acquires output expected values corresponding to all output phase voltages and compares them with the waveform of the control carrier wave for acquiring a turning-on time of each of the plurality of bidirectional switches. Accordingly, the controller controls the matrix power conversion device to switch the three-phase input power so as to change the three-phase output power for driving the motor.

In an embodiment, an off-grid phase splitter includes: a first input port and a second input port that are separately connected to a power supply; a first output port and a second output port that provide a second voltage, and the second output port and a third output port provide a third voltage; a first capacitor connected between the first output port and the second output port; a second capacitor connected between the second output port and the third output port; a first switch circuit and a second switch circuit connected in series to form a first node between the first input port and the second input port, where the first switch circuit and the second switch circuit are unidirectionally switched on in opposite directions,; and an inductor connected between the first node and the second output port.

Apparatus and methods for supplying DC power to control circuitry of a matrix converter is provided. In certain embodiments, a matrix converter includes an array of switches having AC inputs for receiving a multi-phase AC input voltage and AC outputs for providing a multi-phase AC output voltage to a load, such as an electric motor. The matrix converter further includes control circuitry for opening or closing individual switches of the array, and a clamp circuit connected between the AC inputs and AC outputs of the array and operable to dissipate energy of the load in response to an overvoltage condition, such as an overvoltage condition arising during shutdown. The clamp circuit includes a switched mode power supply operable to generate a DC supply voltage for the control circuitry.

A power quality compensation system and a power quality compensation method are provided. The power quality compensation apparatus includes an input filter, a power electronic converter, a controller configured to control the power electronic converter, and a plurality of inductors connected to the power electronic converter. The power quality compensation method includes receiving signals from one or more sensors configured to detect voltage and current from an input side and an output side of the power quality compensation system, calculating reference signals, and using model predictive control to track the reference signals.

An power converter includes an unfolder connected to a three-phase source and has an output connection with a positive terminal, a negative terminal and a neutral terminal. The unfolder creates two unipolar piece-wise sinusoidal DC voltage waveforms offset by a half of a period. A three-input converter connected to the unfolder produces a quasi-sinusoidal output voltage across output terminals. Switches of the converter selectively connect the positive, negative and neutral inputs across the output terminals. A PWM controller controls a first duty ratio and a second duty ratio for the converter based on a phase angle of the source and a modulation index generated from an error signal related to a control variable. The duty ratios are time varying with a fundamental frequency of the source. The modulation index relates to output voltage of the converter, peak voltage or current of the source and/or peak current at the output terminals.

Power controllers (e.g., inductive power transfer (IPT) power controllers) and methods of making and using the same are provided. An IPT power controller can be implemented on direct alternating current (AC)-AC converters and can use only current and voltage measurements to produce multi-power level IPT controller and design switching logic. Using Boolean operators (e.g., AND, OR, Not) applied on a resonant current signal, varying positive energy injections (e.g., 1 to 16 pulses), and varying negative energy injections (e.g., 1 to 16 pulses), up to 32 different active states can be designed.

Disclosed is an AC-AC power converter with multiple AC voltage output branches. The AC-AC power converter is bridgeless and contains only one power stage. The AC-AC power converter consists of only one inductor for power conversion and provides a current source for successively feeding multiple output branches one at a time. Each output branch can be selected by the corresponding switch and its resonant circuit turns the input current source into an AC power source.

A device (2) for the on-demand commutation of an electrical current from a first line branch (14, 3; 36) to another, second line branch (4; 41; 71) is created, which has a number of power semiconductor switching elements (7; 47; 53), which are arranged in series and/or parallel to one another in the second line branch (4; 41; 71), and a control unit (18; 51) for controlling the number of power semiconductor switching elements (7; 47; 53). The control unit (18; 51) is adapted to apply to each of the number of power semiconductor switching elements (7; 47; 53) an increased control voltage (VGE) whose level is above the maximum permissible control voltage specified for continuous operation, in order to switch on or maintain the conduction of the number of power semiconductor switching elements and to cause an increased current flow through it, whose current rating is at least double the nominal operating current. The control unit (18; 51) is further adapted to switch off the number of power semiconductor switching elements after a respectively provided short switch-on duration by switching off the control voltage (VGE) again while they conduct an increased current flow. The device (2) can thus be designed for a higher power in operation, or, at a given operating power, the semiconductor area and size of the device (2) can be reduced.

A pre-charge control method for a hybrid multilevel power converter comprises steps of: (a) controlling access of the current-limiting resistor unit, limiting current from the AC power via the current-limiting resistor unit, and outputting the current; (b) controlling the second capacitor unit to bypass, and charging the first capacitor unit; (c) controlling the access of the second capacitor unit when the first capacitor unit is charged to a third preset voltage, and charging the first and second capacitor units at the same time; (d) controlling the first capacitor unit to bypass when the second capacitor unit is charged to a fourth preset voltage, or the first capacitor unit is charged to a first preset voltage, and charging the second capacitor unit; and (e) controlling the access of the first capacitor units and the current-limiting resistor unit to bypass when the second capacitor unit is charged to a second preset voltage.