A circuit is provided for converting alternating current power into direct current (DC) power and providing a digitally stable ground for operation of a processor-based device. Embodiments of the circuit include a transformer isolating (e.g., via galvanic isolation) a primary side from a secondary side of the circuit. A controller (e.g., a pulse width modulation (PWM) controller) on the primary side directs a switching circuit to selectively permit current flow through a primary side of the transformer to a first ground node on the primary side. A secondary winding of the transformer sources a rectified DC output relative to a second ground node that is isolated from the first ground node. In some cases, compensation on the secondary winding side provides isolated feedback to the controller via an optical isolator or some other circuit. The controller directs the switching circuit based at least in part on the error correction feedback and input from an auxiliary winding of the transformer.

A power supply system includes a plurality of AC output converters connected in parallel for supplying electric power to an AC load. Each of the plurality of AC output converters includes an output impedance connected to the AC load, a PWM converter configured to convert DC power into AC power, and a controller configured to output a voltage command value to the PWM converter. The controller includes a vector adder configured to perform vector addition of a part of a voltage drop occurring due to a current flowing through the output impedance and a voltage command value of the AC load, and a converter configured to output a voltage command value to the PWM converter based on a vector sum obtained through the vector addition.

A converter apparatus includes: a first transformer with two windings; a first full-bridge circuit with four switches, DC input/output units connected to a first DC power supply, and AC input/output units connected via an inductor to one winding of the first transformer; a second full-bridge circuit with four switches, DC input/output units connected to a second DC power supply, and AC input/output units connected via an inductor to another winding of the first transformer; a second transformer with two windings, one being connected via an inductor to the AC input/output units of the first circuit; a third full-bridge circuit with four switches, DC input/output units connected to a third DC power supply, and AC input/output units connected via an inductor to another winding of the second transformer; and a control unit for controlling the switches to supply power between the first to third DC power supplies.

A load control device for controlling the power delivered from an AC power source to an electrical load includes a thyristor, a gate coupling circuit for conducting a gate current through a gate of the thyristor, and a control circuit for controlling the gate coupling circuit to conduct the gate current through a first current path to render the thyristor conductive at a firing time during a half cycle. The gate coupling circuit is able to conduct the gate current through the first current path again after the firing time, but the gate current is not able to be conducted through the gate from a transition time before the end of the half-cycle until approximately the end of the half-cycle. The load current is able to be conducted through a second current path to the electrical load after the transition time until approximately the end of the half-cycle.

Provided is a power conversion device that can be realized with a small circuit and is capable of stably converting AC power inputted from a three-phase power source system into DC power. In a power conversion device: an output terminal of a common converter cell in a J-numbered stage is connected, together with output terminals of common converter cells of the other two phases, to common lines; an output terminal of an independent converter cell in a K-numbered stage is connected to independent lines independently of converter cells of the other two phases; and a plurality of switches comprise a common switch for switching the connection relationship between the common lines and DC buses, and an independent switch for switching the connection relationship between the independent lines and DC buses.

A matrix power converter includes an AC input port arranged to receive three phase power. The AC input port is connected to an input filter arranged to filter switching harmonics of the three phases of the received AC power. The input filter is connected to a 3-to-2 phase matrix converter arranged to convert the three phases of the received AC power to a two phases of AC power. The 3-to-2 phase converter is connected to a primary side of a load transformer arranged to receive the two phases of the AC power. A secondary side of the load transformer is connected to an AC-to-DC converter. The matrix power converter is characterized in that the 3-to-2 phase converter includes a nested directional switch including three power switch cell groups, one for each phase of the received AC input power.

A wireless power transfer system using a resonant rectifier circuit with capacitor sensing. A wireless power transfer system includes a power receiver resonant circuit and a synchronous rectifier. The power receiver resonant circuit includes an inductor and a capacitor connected in series with the inductor. The synchronous rectifier is configured to identify zero crossings of alternating current flowing through the inductor based on voltage across the capacitor, and control synchronous rectification of the alternating current based on timing of the zero crossings.

Embodiments of the present disclosure provide a method for controlling a converter and a converter system. The method includes obtaining voltage signals indicating phase voltages of three phases at AC side of a converter, determining, based on the voltage signals, carrier signals of a three-phase switching branches of the converter, wherein carrier signals of two of three phases have the same phase with each other and have a different phase from a carrier signal of the rest phase of the three phases, and magnitude of a phase voltage of the rest phase is between the phase voltages of the two phases, and generating, based on the determined carrier signals and modulation wave signals of the three-phase switching branches, control signals of the three-phase switching branch.

A protected direct-drive depletion-mode (D-mode) GaN semiconductor half-bridge power module is disclosed. Applications include high power inverter applications, such as 100 kW to 200 kW electric vehicle traction inverters, and other motor drives. The high-side switch is a normally-on D-mode GaN semiconductor power switch Q1 in series with a normally-off LV Si MOSFET power switch M1 and the low-side switch is a normally on D-mode GaN semiconductor power switch Q2. The gates of both Q1 and Q2 are directly driven. M1 in series with Q1 provides a high-side switch which is a normally-off device for start-up and fail-safe protection. M1 may also be used for current sensing and overcurrent protection. For example, a control circuit determines an operational mode of M1 responsive to a UVLO signal and a voltage sense signal indicative of an overcurrent event. Examples of single phase and three-phase half-bridge modules and driver circuits are described.

A device for extinction angle control of a high voltage direct current (HVDC) system, includes: a converter reactive power calculator calculating a reactive power variation amount of a converter included in the HVDC system, depending on firing angle control of the converter; an alternating current (AC) system short circuit level calculator calculating a short circuit level of an AC system by applying the reactive power variation amount to a short circuit level formula of the AC system connected to the HVDC system; an extinction angle variation value calculator calculating an extinction angle variation value of the converter, corresponding to the short circuit level; and an extinction angle controller controlling an extinction angle of the converter, depending on an extinction angle control value reflecting the extinction angle variation value.