Abstract: A motive power outputting apparatus includes motor generators, inverters, and a transformer. The motor generator includes a three-phase coil, and the motor generator includes a three-phase coil. The inverter allows an in-phase AC current to pass through an U-phase coil, a V-phase coil and a W-phase coil of the three-phase coil. The inverter allows an in-phase AC current, which has a phase being inverted relative to that of the in-phase AC current passing through the three-phase coil, to pass through an U-phase coil, a V-phase coil and a W-phase coil of the three-phase coil. The transformer converts an AC voltage generated in a primary coil and outputs a commercial-power-source AC voltage to terminals.

Abstract: There is provided an inverter apparatus islanding operation detecting method capable of surely detecting an islanding operation with a simple construction. A distortion for causing a variation in an output frequency of an inverter apparatus in an islanding operation stage is applied to an inverter output waveform. With this arrangement, even when the inverter apparatus is disconnected from an AC power system in a state in which a power factor of a load impedance is proximate to one, a frequency variation is generated in an inverter output, thereby ensuring detection of the islanding operation.

Abstract: A high-frequency, high-density power conversion system providing lossless power switching with a single or double-ended power converter, the single ended converted including a pair of input terminals for received dc or rectified ac voltage, a transformer with its primary across the input terminals, a transistor in series between an input terminal and the transformer primary, and a dedicated inductor in series between the other input terminal and the other side of the primary, in which the transistor is switched to provide a sinusoidal output current pulse to the transformer primary.

Abstract: A power source device restricts any increase in a switching current to switching elements commonly used in two such different power source circuits as chopper and inverter circuits, while maintaining control independence of these circuits, by setting a period in which among currents flowing to the commonly used switching elements, the current flowing at least from one of the power source circuits has a polarity inverse to that of the current from at least the other power source circuit, to be in mutually cancelling directions.

Abstract: A power supply apparatus having an AC power supply, a transformer, a switching element and a control circuit for controlling an operation of the switching element: where an electrical current is supplied to the primary side of the transformer intermittently when a main unit of an electrical appliance to which the power supply apparatus is applied is in a standby mode so that unnecessary power consumption is reduced. Further, a capacitance is provided between the AC power supply and the control circuit instead of the conventional initializing resistance and the control circuit is driven using an electrical current going through a reactance component of the capacitor, so that the energy loss is not caused any more by the initializing resistance.

Abstract: The invention relates to an inverter arrangement for simultaneous control of a stator flux and a torque of an electric machine (M). In the invention, the inverter of the inverter arrangement is controlled on the basis of a stator voltage reference (u.sub.sref) defined on the basis of the error variables (T.sub.err, .PSI..sub.err) of the torque and the stator flux; on the basis of the stator voltage reference, in turn, are defined reference values for the phase voltages (u.sub.aref, u.sub.bref, u.sub.cref) of the stator voltage. The phase voltages (u.sub.a, u.sub.b, u.sub.c) of the stator voltage supplied to the electric machine (M) are controlled by a feedback voltage controller (VAC) to correspond to the defined reference values (u.sub.aref, u.sub.bref, u.sub.cref) of the phase voltages.

Abstract: A start-up circuit with lower current requirements than a conventional start-up circuit is disclosed. The start-up circuit may achieve lower current requirements by reducing the current of the start-up circuit to approximately zero when the bandgap circuit reaches a predetermined value. For example, the start-up circuit may peak at a current of 3.3 micro Amps in order to ensure that the bandgap circuit reaches the predetermined voltage. Thereafter, the current for the start-up circuit may be reduced to approximately zero once the bandgap circuit no longer requires the start-up circuit.

Abstract: A voltage control system that provides an output voltage of constant value to a load. The control system includes voltage supply means for providing the output voltage to the load. A feedback circuit supplies a feedback current. A summing circuit algebraically sums the feedback current and a reference current to provide an error signal that changes as the feedback current changes. These changes affect the amplitude of the output voltage delivered to the load. The error signal is processed by a voltage adjustment means including an error amplifier that amplifies the error signal for use in making an adjustment to the output voltage so as to maintain its constant value. A gain increasing means responds to transient changes in output voltage to momentarily increase the error amplifier gain to shorten system recovery time to constant output voltage.

Abstract: A power circuit for controlling the amount of power delivered to a solenoid coil is disclosed. A current mode pulse width modulation controller is employed to interrupt the flow of current through a power branch of the circuit. A rectifying bridge enables use of the power circuit with either AC or DC power sources. The power circuit includes a startup current source for initially energizing the pulse width modulation controller. Two feedback voltages, one representing the compensated current through the power branch of the circuit and one representing the output voltage of the power circuit are used by the pulse width modulation controller to output pulses of varying duration at constant frequency to a field effect transistor. The opening of the field effect transistor interrupts the flow of current in the power branch of the circuit.

Abstract: A DC power supply apparatus includes a rectifier circuit which rectifies an input commercial AC voltage. The rectifier output voltage is smoothed in a smoothing capacitor. The DC voltage from the capacitor is converted to a high-frequency voltage in an inverter. The high-frequency voltage from the inverter is voltage-transformed by a transformer into a voltage-transformed, high-frequency voltage, which is then converted back into a DC voltage in a high-frequency-to-DC converter circuit. When an input commercial AC voltage is applied to the DC power supply apparatus, a pre-charging circuit pre-charges the smoothing capacitor from the input AC voltage. If a voltage having a magnitude larger than a prescribed value is applied to the DC power supply apparatus, an overvoltage protection circuit renders the rectifier circuit and the pre-charging circuit inoperative.

Abstract: In a power converter having a power switch, a rectifier and a snubber circuit having an auxiliary switch that moderates reverse recovery currents associated with the rectifier, a driver for the auxiliary switch, a method of driving the auxiliary switch and a power converter employing the driver and method. In one embodiment, the driver includes a first driver switch, coupled between the power switch and the auxiliary switch, that allows the auxiliary switch to turn on concurrently with the power switch. The driver also includes a second driver switch, coupled between the auxiliary switch and an output of the power converter, that prevents a voltage of the auxiliary switch from rising above an output voltage of the power converter to assist the auxiliary switch in turning off.

Abstract: A DC--DC converter includes a transformer having a primary winding and a secondary winding. The secondary winding includes first and second terminals. An input circuit is connected to the primary winding for coupling an input DC voltage to the primary winding. A first output channel is connected to the first terminal of the secondary winding, and is connected to a first output. The first channel includes a first switch connected in series with a first inductor. A second output channel is connected to the second terminal of the secondary winding, and is connected to a second output. A first and a second capacitor connect the first and second outputs to a return lead. A second switch connects the first output channel to the return lead. A third switch connects the second output channel to the return lead. A pulse width modulator is connected between one of the outputs to drive the input circuit.

Abstract: A multiple pulse-width modulation power conversion device for variable-speed drive of a three-phase AC motor comprises three units (11.sub.1, 11.sub.2, and 11.sub.3), each unit including n (n.gtoreq.2) batteries (12.sub.11, 12.sub.12, and 12.sub.13), each made up of a DC power supply or at least one battery cell, and n power converters (13.sub.11, 13.sub.12, and 13.sub.13) for converting the DC power of each of these batteries to single-phase AC power. Single-phase AC terminals within each unit are connected in series, and of the single-phase AC terminals within each unit, one of the single-phase AC terminals that is not connected to the single-phase AC terminal of another power converter is connected to a star connection, and the other is connected to a respective one of three input terminals of a three-phase AC motor. The power conversion device further comprises control circuits (14.sub.11, 14.sub.12, . . . , 14.sub.

Abstract: A feedback amplifier generates a control signal based on an output voltage and a reference voltage. A first ramp signal generating circuit generates a first ramp signal that synchronizes with a pulse signal from an oscillator. A second ramp signal generating circuit generates a second ramp signal according to the state of a latch circuit. A comparator generates a reset signal when the total of the signal representing an inductor current and the respective levels of the first and the second ramp signals becomes higher than the level of the control signal. The latch circuit is set by the pulse signal from the oscillator and is reset by the reset signal. A driver circuit comprises a boost capacitor, and drives the switch according to the state of the latch circuit.

Abstract: A power factor improving circuit for reducing a harmonic current component contained in an AC input current and for achieving an excellent power factor and efficiency in a circuit having a rectifier circuit, provided between a rectifier circuit and a half-bridge-type inverter, including a discharging diode and a smoothing capacitor connected in series to each other and in parallel between output terminals of the rectifier circuit, a charging half-bridge rectifier connected to the smoothing capacitor, and a high-frequency capacitor and high-frequency inductor connected in series to each other and between an input terminal of the charging half-bridge rectifier and a connecting point of two transistors of the half-bridge-type inverter.

Abstract: A power factor controller, a method of controlling power factor and a power converter employing either the controller or the method. The controller includes: (1) a ramp circuit that senses an output voltage of a converter being controlled and generates an intermediate waveform that rises as a function of a magnitude of the output voltage and (2) a drive circuit, coupled to the ramp circuit, that senses a current in the converter and causes the intermediate waveform to fall at a time that is a function of a magnitude of the current, the drive circuit generating a drive signal for the converter from the intermediate waveform.

Abstract: A method and apparatus for using feedback to control the output voltage of a Switch Mode Power Supply (SMPS) that is used as the input voltage to subsequent Low Drop Out (LDO) linear voltage regulators. A multiplexer and Analog to Digital Converter (ADC) are used to successively sample the output voltages of multiple parallel LDO regulators. The digitized voltage values are input to a digital processor that compares the LDO regulator output voltages with acceptable limits previously stored in memory. The digitized voltage values are used by the digital processor to control the output voltage of a SMPS that is used as the input voltage to the LDO regulators. The output voltage of the SMPS, and thus the input of the LDO regulators, is reduced to the minimum value that retains full performance of the LDO regulators. Operating each LDO regulator at full regulation ensures full performance of the LDO regulators. Minimizing the input voltage to the LDO regulators maximizes the efficiency of the total power supply.

Abstract: A partial-voltage buck regulator controls a high-voltage bus to a full-bridge circuit such that overall switching losses are reduced and distributed. Low-voltage buck regulator devices are PWM-switched when high output voltage is needed, and high-voltage bridge devices are PWM-switched when low output voltage is needed. A variable input power supply, which may be operated in a high power factor mode, can adjust the input bus voltages to achieve optimum performance for a given magnetic resonance imaging sequence.

Abstract: The present invention provides a series control type regulator which can decrease rapidly an output voltage regardless of heaviness or lightness of a load when a first transistor for controlling an output voltage is set to a state of stop of operation. When a switching circuit sets the first transistor from a state of operation to a state of stop, at the same time an output capacitor is discharged by causing to a discharge circuit connected in parallel to the output capacitor. The discharge circuit starts operating by turning on a third transistor, which turns on by a current flowing to voltage dividing resistors of a detection circuit being used as a base current. The voltage dividing resistors of the detection circuit are also used as resistors for setting a base current of the third transistor.

Abstract: A DC voltage converter is intended to multiply an input voltage and includes N elementary cells (ECi) in a cascade arrangement, each cell being intended to store the value of the input voltage in two capacitors (Ci1, Ci2). The charging and discharging of the capacitors (Ci1, Ci2) is controlled by transistors (Ni1, Ni2) whose conduction is controlled by the same control signal.