A high voltage direct current power transmission series valve group control device, is used for regulating a series circuit having two or more valve groups provided with controllable power semiconductors respectively. Each valve group is provided with a current regulation unit and a voltage regulation unit. The current regulation unit controls a direct current current flowing through a valve group corresponding thereto, and the voltage regulation unit controls a voltage across two ends of a valve group corresponding thereto. One valve group is selected from the series valve group as a master control valve group, while the others are taken as slave control valve groups. The master control valve group selects a trigger angle output by the current regulation unit to control same, and the slave control valve group selects a trigger angle obtained after the trigger angle transmitted from the master control valve group and an output value of the voltage regulation unit pass through a subtractor to control same.

A cascaded power electronic transformer and a method for controlling the same are provided. The method includes: calculating electrical angles θ.sub.i1 and θ.sub.kps of an s.sup.th transformer and a compensation electrical angle θ.sub.j of a j.sup.th transformer; adding the compensation electrical angle θ.sub.j to the electrical angle θ.sub.kps of the j.sup.th transformer, to obtain a compensated electrical angle θ.sub.kps of the j.sup.th transformer; and calculating a square wave of a bridge arm voltage of each of the m primary converters and the r secondary converters of the s.sup.th transformer based on the electrical angle θ.sub.i1 and the electrical angle θ.sub.kps of the s.sup.th transformer after compensation.

At a first node (N1), an intermediate voltage potential occurs between a voltage potential of the first input terminal (P1) and a voltage potential of the second input terminal (P2). A second node (N2) is connected to ends (b1 to b3) of primary windings (w1, w4, w7) of transformers (T1 to T3) of LLC resonant converters (11 to 13). A switch circuit is connected between the first node (N1) and the second node (N2). A control circuit (15) is configured to turn on a switch circuit (SW) when a load current of a load apparatus (6) connected to a first output terminal (P3) and a second output terminal (P4) is equal to or smaller than a predetermined criterion and turn off the switch circuit (SW) when the load current of the load apparatus (6) is larger than the predetermined criterion.

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.

A load control device for controlling power delivered from an alternating-current power source to an electrical load may comprise a controllably conductive device, a control circuit, and an overcurrent protection circuit that is configured to be disabled when the controllably conductive device is non-conductive. The control circuit may be configured to control the controllably conductive device to be non-conductive at the beginning of each half-cycle of the AC power source and to render the controllably conductive device conductive at a firing time during each half-cycle (e.g., using a forward phase-control dimming technique). The overcurrent protection circuit may be configured to render the controllably conductive device non-conductive in the event of an overcurrent condition in the controllably conductive device. The overcurrent protection circuit may be disabled when the controllably conductive device is non-conductive and enabled after the firing time when the controllably conductive device is rendered conductive during each half-cycle.

A converter system includes a rectifier, a DC link stage and an inverter connected in series. A control unit includes a slow reference frame angle determination unit that generates a slow reference frame angle θ.sub.r,slow representing an angle that is slowly following a grid phase deviation, and a fast Phase Locked Loop generating a fast reference frame angle θ.sub.r,fast representing an angle that is fast following a grid phase deviation. The control unit uses the slow reference frame angle θ.sub.r,slow and the fast reference frame angle θ.sub.r,fast to control the rectifier output current, and the fast reference frame angle θ.sub.r,fast to control the inverter output voltage and to synchronize the inverter output voltage with the grid voltage.

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.

Technologies for alternating current regulation controller include a controller configured to determine a voltage duty cycle based on a target voltage, and to determine a delay time based on the voltage duty cycle. The controller is coupled to input phases of an alternating current generator having multiple phases. Each phase is coupled to a silicon controlled rectifier. For each phase, the controller identifies a rising edge asserted on the input phase, waits the delay time after identifying the rising edge, and asserts an output pulse on an output driver coupled to the silicon controlled rectifier coupled to the input phase in response to waiting the delay time. Other embodiments are described and claimed.

The power converter A1 includes a semiconductor device B1, and a substrate H on which the semiconductor device B1 is mounted, where the semiconductor device B1 includes a control chip constituting a primary control circuit, a semiconductor chip constituting a secondary power circuit, and a transmission circuit for electrically insulating the primary control circuit and the secondary power circuit and for signal transmission between the primary control circuit and the secondary power circuit. The substrate H has a conductive portion K. The power converter A1 includes a connecting terminal T1 disposed on the substrate H and electrically connected to the conductive portion K. The power converter A1 includes a conductive path D1 that is at least partially formed by the conductive portion K of the substrate H, and that electrically connects the primary control circuit and the connecting terminal T1. Such a configuration contributes to downsizing the power converter A1.

An apparatus attachable to a luminaire includes circuitry for converting alternating current power into direct current (DC) power and providing a digitally stable ground for operation of a processor-based device. The circuitry includes a transformer isolating a primary side from a secondary side of the circuitry. A switching controller (e.g., a pulse width modulation 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. 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, such as via an optical isolator. The controller directs the switching circuit based at least partially on the feedback and input from an auxiliary winding of the transformer.