Abstract: A current measurement circuit, for wireless charging systems, for instance, comprises a differential input configured to have applied an input voltage sensed across a shunt resistor traversed by a current to be measured, a voltage reversal switch arrangement selectively switchable to reverse the polarity of the input voltage as applied between a first and a second voltage sensing nodes as well as a first and a second current flow line between the voltage sensing nodes and ground. A difference resistor intermediate the two current flow lines is traversed by a current which is a function of the input voltage as applied to the first and second sensing nodes via the voltage reversal switch arrangement. First and second current sensing nodes at the two current flow lines are coupled to a differential current output via a current reversal switch arrangement selectively switchable to reverse the output current polarity.

Abstract: A multifunction power conversion device for dynamical detection includes an input filter unit, a transformer, a switching transistor, a driving controller, a feedback unit and an output unit. Two sensing signals from the primary and auxiliary coils of the transformer form a current sensing zero detection signal. The digital control unit of the driving controller determines if a current flowing through a secondary coil of the transformer is reduced to zero due to discharging, and further finds valley of the current of the secondary coil. The switching transistor is turned on after a preset number of the valley and then turned off by a process of current sense. Therefore, the present invention greatly reduces switching loss, increases efficiency of power conversion, and particular, enhances flexibility of application to meet actual requirements by simply updating program executed by the digital control unit.

Abstract: A device for improving efficiency of an induction motor soft-starts the motor by applying a power to the motor that is substantially less than the rated power of the motor then gradually increasing the power while monitoring changes in current drawn by the motor, thereby detecting when maximum efficiency is found. Once maximum efficiency is found, the nominal motor current is found and operating ranges are set. Now, the phase angle between the voltage and the current to the motor is measured and power to the motor is increasing when the phase angle is less than a minimum phase angle (determined during soft-start) and power to the motor is decreased when the phase angle is greater than or equal to the minimum phase angle as long as the voltage does not fall below a minimum voltage determined during soft-start.

Abstract: The invention relates to a method for operating an electric motor (2) having a phase angle control with the following steps: Applying an AC voltage to a series connection of the electric motor (2) and a switching element (4), particularly a triac, wherein the switching element (4) connects through by applying an ignition signal and suppresses the flow of a current if the amount of current falls below a holding current; determining the time of a zero crossing of a virtual motor current that would flow if the switching element (4) were connected through; and turning on the switching element (4) at an activation time that is dependant on the time of the zero crossing of the virtual motor current.

Abstract: A winding switching apparatus includes a winding switching device and a drive circuit. The winding switching device is configured to switch a plurality of windings of an AC motor. The drive circuit is configured to control the winding switching device. The winding switching device includes a winding switch, a diode bridge, and a capacitor. The diode bridge includes a positive-side DC output terminal, a negative-side DC output terminal, and AC input terminals. The AC input terminals corresponds to respective phases of the AC motor. The positive-side and negative-side DC output terminals are respectively connected to positive-side and negative-side DC buses provided in an inverter. The AC input terminals are respectively connected to winding-switching terminals corresponding to the respective phases of the AC motor. The AC input terminals are respectively connected to phase terminals provided in the winding switch.

Abstract: A phase detecting device includes a power input unit that receives an AC voltage; a phase detector that detects zero-crossing points of the AC voltage, and outputs a phase detecting signal when the zero-crossing points of the AC voltage are detected; and a power switch that selectively cuts off a flow of AC into the power input unit in response to a mode control signal.

Abstract: A zero-crossing point detection circuit includes a hot line input, a neutral line input, a first zero-crossing point output, and a first optical coupler. The first optical coupler includes a first light-emitting diode (LED) and a first optical transistor. The hot line input and neutral line input are respectively connected to two terminals of the first LED. An emitter of the first optical transistor is grounded. A collector of the first optical transistor is connected to a direct current (DC) power source. The collector of the first optical transistor is also connected to the first zero-crossing point output.

Abstract: A solid state power controller (SSPC) (100) includes a power switching controller (30) and power switching devices (PSDs) (20A, 20B, 20C) for controlling each phase of a multiple-phase load to switch-on or -off at a zero-crossing point of a corresponding phase of a multiple-phase power source. The power switching controller (30) may include an ASIC (25A, 25B, 25C) for controlling each PSD (20A, 20B, 20C) to switch the corresponding load phase on or off. The ASIC (25A, 25B, 25C) may be configured to control the PSD (20A, 20B, 20C) to switch-on the load phase at a detected zero-crossing point of the voltage supplied by the corresponding phase of the power source, and to switch-off the load phase at a detected zero-crossing point of the load current supplied by the corresponding phase of the power source.

Abstract: A driver including first and second buffers connected in parallel between a power source and a return path. In one configuration, the buffer outputs are commonly connected to an external coil and optionally a capacitive load. In another configuration, the buffers' outputs independently drive first and second external transistors. The external transistors are in series between a supply voltage source and its return path.

Abstract: An electronic control, with a floating ac power supply, that compares the digital signals produced by connections between ac circuit nodes and digital nodes to determine whether path(s) in ac circuits containing the ac nodes are intact or open. The connections are made through passive components which limit the current between nodes to levels the digital devices can safely handle. An open path indicates to the control that a switching device is open, a connection has failed, or a that a load component has failed or is missing. An intact path indicates a closed switch or a present and presumably functional load component. Proper connections enable the control to detect the state of multiple paths while still being able to detect zero crossings. The method can determine the state of ac paths even if hot and neutral connections are inadvertently reversed.

Abstract: In a power supply device including a full-wave rectifying and smoothing circuit powered from a commercial AC power supply via two power supply lines, a switching regulator for separating and stepping down the output from the full-wave rectifying and smoothing circuit to output a desired DC voltage, and two capacitors after the full-wave rectifying and smoothing circuit for the terminal noise suppression purpose, a zero-cross detection circuit includes a transistor of which the emitter is connected to the low-voltage output terminal of the full-wave rectifying and smoothing circuit for outputting a zero-cross detection signal from the collector; a first resistor is connected between the base and emitter of the transistor; a second resistor is connected between one of the power supply lines and the base of the transistor; and a third resistor is connected between the other power supply line and the emitter of the transistor.

Abstract: The present invention is connected across a sense resistor which carries a current of interest. A first pair of cross-coupled switches are connected between the sense resistor and respective input capacitors, and a second pair of cross-coupled switches are connected between the input capacitors and the inputs of an amplifier having differential inputs and outputs. Feedback capacitors are connected between each of the amplifier's outputs and inputs. A control circuit operates the cross-coupled switches in accordance with a switching cycle, during which the connections between the sense resistor and the input capacitors are interchanged, after which the connections between the input capacitors and the differential amplifier are interchanged. When so arranged, the sensed voltage is sampled on the input capacitors and transferred to the feedback capacitors to produce a differential output voltage Vout from the differential amplifier which is proportional to the current of interest.

Abstract: A zero crossing control circuit of a bidirectional switch including two transistors of complementary types connected in parallel between the gate of the bidirectional switch and the main reference terminal of the bidirectional switch, the gate of the bidirectional switch being connected to a control source via a first resistor, and each of the control terminals of the transistors being connected to the second main terminal of the bidirectional switch via a second resistor of high value, a zener diode being interposed between the second resistor and each of the control terminals according to a biasing adapted to turning on each of the transistors when the zener threshold is exceeded.

Abstract: The present invention relates to a circuit for controlling a triac at the voltage zero. Two transistors of complementary types are connected in parallel between the gate and the main reference terminal of the triac. The control terminals of the transistors are interconnected and connected to the second main terminal of the triac via a resistor of high value. The gate of the triac is connected to a control potential source via a second resistor.

Abstract: A power controller device which uses a voltage-to-frequency converter in conjunction with a zero crossing detector to linearly and proportionally control AC power being supplied to a load. The output of the voltage-to frequency converter controls the "reset" input of a R-S flip flop, while an "0" crossing detector controls the "set" input. The output of the flip flop triggers a monostable multivibrator controlling the SCR or TRIAC firing circuit connected to the load. Logic gates prevent the direct triggering of the multivibrator in the rare instance where the "reset" and "set" inputs of the flip flop are in coincidence. The control circuit can be supplemented with a control loop, providing compensation for line voltage variations.

Abstract: A method for controlling the power supplied by a sinusoidal source (1) wherein the power supplied is determined, on the one hand, by the integer number of the pulses comprised in a burst which is fully switched through to the load (17) at the output of the circuit and, on the other hand, by the length of the last phase angle-controlled pulse within each burst. To provide the actuation signal for a switch which connects the sinusoidal pulses to the load, the zero passages of the sinusoidal pulses (A) of the sinusoidal source (1) are determined in a zero passage detector (5). A division circuit (7) generates trigger pulses (C) of a lower frequency from the zero passage pulses (B), which trigger pulses reset the ramp voltage (D) of a sawtooth generator (9). The ramp voltage (D) is compared in a comparator (15) to a regulated quantity (E) of a desired value device (11).

Abstract: A triac (100) utilizes an FET (107) to inhibit firing of a transistor (112) that forms a portion of the SCR of the triac (100). A DMOS transistor (106) is used to supply a substantially constant bias current to the transistor (107) in order to facilitate rapid turn-on of the transistor (107) around the zero-crossing of the voltage applied to the triac (100).

Abstract: An SCR control circuit which drives the SCR between conduction and non-conduction states in accordance with values sensed by a polarity sensing circuit. The control circuit generating a signal for the gate which is of a constant value, at different temperatures.

Abstract: A lighting control system distributes both the alternating current supply and control signals representing desired adjustments to fixture parameters, such as intensity, via connections including power contacts and, for control signals, an electrically isolating coupling comprising an effective source and detector.

Abstract: An arrangement for controlling a zero crossing switch in order to connect a source of zero crossing AC voltage to and disconnecting it from an AC load line is disclosed herein along with its method of operation. To this end, means are provided for producing externally controlled command signals intended to control when the switch connects and disconnects the load line to and from the AC voltage. At the same time, a specific window of time is selected, which window begins a particular period of time prior to and includes at least certain zero crossing points of the AC voltage. Internally controlled command signals are produced in response to the AC voltage and externally controlled signals for actually controlling when the switch connects (ON) and disconnects (OFF) the load to and from the AC voltage.