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.

A voltage source converter has a half bridge (18) with two current valves (19, 20) connected in series and an arrangement configured to carry out voltage measurements for determining a value of the DC voltage between opposite poles (21, 22) of a DC side of the converter. Each current valve comprises a semiconductor device (23, 24) controlled by an associated gate drive member (29, 30), each forming gate drive parts of one gate drive unit (28) in common to both current valves. The gate drive unit (28) comprises an isolated two-way communication link (33) between the gate drive members. The arrangement is included in the gate drive unit and configured to measure the entire DC voltage between said opposite poles (21, 22). A converter control device (31) calculates and sends control signals to the gate drive unit based on the result of the voltage measurement.

A matrix converter control device includes a plurality of delay circuits which correspond to logic change timings of a plurality of input pulse width modulation (PWM) signals for controlling ON and OFF states of a plurality of switching elements included in a matrix converter. Specifically, the plurality of delay circuits are a first delay circuit, a second delay circuit, a third delay circuit, a fourth delay circuit, and a fifth delay circuit. Each of the plurality of delay circuits delays an input PWM signal by an amount of delay set for the delay circuit at a logic change timing corresponding to the delay circuit.

A rectifier circuit includes a switch circuit including at least one bidirectional switch and configured to rectify an alternating-current voltage of an alternating-current voltage line, and a surge suppression circuit connected to the alternating-current voltage line and configured to suppress a surge voltage of the switch circuit, where a dead time when the bidirectional switch is turned off is present.

An AC-AC matrix converter that converts an input multiphase periodic voltage includes N input voltages that are out of phase into an output multiphase periodic voltage comprising N output voltages that are out of phase, the converter comprising a square matrix array comprising N.sup.2 switches. The converter comprises command and control electronics that periodically perform the following two functions: storing N! voltage summations, each voltage summation corresponding to one switch configuration, each switch configuration relating one and only one out-of-phase input voltage and one and only one out-of-phase reference voltage, each voltage summation being the summation of the N differences in absolute value between one and only one out-of-phase input voltage and one and only one out-of-phase reference voltage; switching the matrix array of switches to apply the configuration corresponding to the lowest voltage summation.

An improved AC power supply is described. The supply identifies the load through monitoring the current and voltage wave forms and phase relations with the AC Mains. The comparison is done in conditions where the power to the load is programmably varied through use of a control switch located in the line and neutral between the AC mains and the load. The program of controlling the switch is varied to optimize the ability to distinguish similar load types. The switch can be further used to control power to the load that varies according to a set of rules based upon the identity of the load. In a preferred embodiment, the design enables high efficiency with minimal components that may be fully integrated onto silicon.

A power converter includes an unfolder connected to a three-phase source and has an output connection with three output terminals. A three-input converter connected to the unfolder produces a quasi-sinusoidal output voltage across converter output terminals. Switches of the converter selectively connect each of the three output terminals across the converter output terminals. A pulse-width modulation 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 at a rate related to 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.

Techniques are provided for controlling alternating current (AC) power which is supplied to an inductive load by an AC switch. For example, the AC power is controlled by a process which comprises detecting zero-voltage crossings of an AC voltage waveform of the AC power, monitoring a load voltage to detect for a presence of inductive flyback voltage when the AC switch is placed into a turned-off state, and determining a delay time to place the AC switch into the turned-off state subsequent to a detected zero-voltage crossing of the AC voltage waveform, when inductive flyback voltage is detected in the load voltage, so that the AC switch is placed into the turned-off state at a time which substantially coincides with a zero-current crossing of load current of the inductive load, to thereby suppress the generation of inductive flyback voltage when the AC switch is placed into the turned-off state.

A wireless power transmission method of control where an electrical parameter of a resonant circuit, which is part of a transmitter antenna tuning and coupling unit, determines in some part the regulation current level target or power level target of the resonant circuit. By using an electrical parameter of a resonant circuit to establish a current or power regulation level of the resonant circuit, a maximum limitation is established for the electrical current and voltage of the antenna tuning and coupling unit in order to operate the electrical elements within safe design limits. Additionally, energy is managed entering the transmitter antenna tuning and coupling unit for variable load at the receiver.

Operating an electrical load controller includes, in one aspect, detecting zero-crossings of an AC waveform, determining periods each corresponding to a full cycle of the AC waveform, determining a frequency of the AC waveform based on the determined periods, and controlling a supply of AC power to a load based thereon using the determined frequency to fire a switching circuit of the electrical load controller. In another aspect, a method includes maintaining a minimum on-time for which a control signal to the switching circuit is to remain in an ON state to fire the switching circuit; based on a desired load level setting of the electrical load controller, setting a corresponding control signal turn-on time to turn the control signal to the ON state to conduct the supply of AC power to the load, the control signal turn-on time corresponding to a firing angle of half cycles of the AC power; selecting a control signal turn-off time to turn the control signal to the OFF state, where the selecting is made between (i) a first turn-off time equal to the set turn-on time plus the minimum on-time, and (ii) a second turn-off time equal to a default turn-off time for turning the control signal to the OFF state, the control signal turn-off time corresponding to a second angle of half cycles of the AC power; and controlling the supply of AC power to the load by selectively controlling the switching circuit to conduct the supply of AC power to the load, the controlling the supply of AC power to the load including: based on turning the control signal to the ON state during a half cycle of the AC power at the set control signal turn-on time, holding the control signal in the ON state until the selected control signal turn-off time during the half cycle.