Abstract: A power subsystem is actively optimized to improve total subsystem efficiency in a way that is responsive to changes in load requirements, power supply variations, and subsystem temperature variations. Detailed, multidimensional power loss models are developed for constituent devices which are then combined into a power subsystem containing a controller and circuity for measuring device operating parameters such as input and output voltage, output current, and temperature. Operating parameters are continually monitored, and set points are correspondingly changed based on the detailed power loss models to achieve maximum overall efficiency for the instantaneous operating state of the system.

Abstract: A circuit and system topology includes a plurality of controller units configured to provide a high reliability power system. Sub-systems and devices are controlled via the plurality of controller units such that the high reliability power system remains functional, even subsequent to controller unit, sub-system and device failures.

Abstract: An AC-to-DC power converter configured to provide power factor correction and a single isolated low-voltage output. The power converter includes a single-stage resonant power converter including an isolation transformer, a resonant tank, a rectifier, and a bulk storage capacitor coupled to an output of the isolation transformer. In typical applications, at least one non-isolated power converter is coupled to the output of the single-stage isolated power factor correction converter.

Abstract: There is provided a switching power supply device having one half-wave rectifying circuit made up of switching elements complementarily turned on or off, a reactor, a current resonance capacitor, a transformer, and a rectifying diode and another half-wave rectifying circuit made up of switching elements complementarily turned on or off, a reactor, a current resonance capacitor, a transformer, and a rectifying diode and configured so that the half-wave rectifying circuits commonly charges a smoothing capacitor. The switching elements are turned on or off according to a voltage of the smoothing capacitor and other switching elements are turned on or off based on a difference between a charging voltage of the current resonance capacitor and a charging voltage of the current resonance capacitor. As a result, power energy fed from the half-wave rectifying circuits connected in parallel is made equal.

Abstract: A medium voltage adjustable frequency drive includes an input isolation transformer having a three-phase input and a three-phase output, a converter having a three-phase input electrically connected to the three-phase output of the input isolation transformer and an output providing a direct current bus, an inverter having an input electrically connected to the output of the converter and a three-phase output, and a pre-charge circuit. The pre-charge circuit includes a ferro-resonant transformer circuit having a primary winding structured to input a low voltage and a secondary winding structured to output a medium voltage and provide a constant current source. The pre-charge circuit also includes a medium voltage diode bridge having an input receiving the medium voltage from the secondary winding of the ferro-resonant transformer circuit and an output structured to provide the constant current source to the direct current bus.

Abstract: In a circuit apparatus for transformerless conversion of an electric direct voltage of a two-pole direct voltage source (1) connected to ground having a first voltage pole (+) and a second voltage pole (?) into an alternating voltage, hazardous capacitive leakage currents are avoided by connecting the direct voltage source (1) to ground and the DC-AC converter (400) is operated at a controlled intermediate circuit voltage, a DC-DC converter stage (300) being connected between the direct voltage source (1) and the DC-AC converter (400), said DC-DC converter stage providing at its output a +/? voltage that is symmetrical with respect to the grounding point, two series-connected capacitors (41, 42) having the same polarity and being connected to ground at their connecting point (V) and controlled are charged by two buck-boost choppers (100, 200) connected one behind the other.

Abstract: Control device for a switching converter structure comprising at least a first and a second interleaved converter, wherein the control device is configured to designate one converter as master and at least the other converter as slave, to set a time delay of the operating cycle of the slave converter and to synchronize the master and the at the least one slave converter.

Abstract: Systems and methods of converting alternating current (AC) power into direct current (DC) power at an intermediate DC voltage are disclosed. Briefly described, one system embodiment comprises a separated front end rectifier system that provides intermediate voltage, direct current (DC) power to a plurality of loads, comprising a modular alternating current to direct current (AC/DC) rectifier coupled to an AC power system that converts received AC power to DC power at a rectified DC voltage, a rectified DC voltage bus coupled to the AC/DC rectifier and at least one modular direct current to direct current (DC/DC) conversion unit coupled to the rectified DC voltage bus and to an intermediate DC voltage bus.

Abstract: In a current resonance type multi-phase DC/DC converting apparatus for combining, using an output capacitor, M converter output voltages produced by M current resonance type multi-phase DC/DC converters connected in parallel to each other to produce an output voltage, each of the M current resonance type multi-phase DC/DC converters has N current resonance type DC/DC converters connected in parallel with one another. The N current resonance type DC/DC converters have N resonance circuits, respectively. Each of the M current resonance type multi-phase DC/DC converters shares a resonance inductor of the N resonance circuits.

Abstract: A switched current power converter includes an input power source, an output terminal, and a plurality of current stages. Each of the current stages includes a converter coupled to the input power source for providing a current and a switch circuit that selectively couples the current in such current stage to the output terminal. A control circuit decouples the input power source from the current stage converters upon detection of a low load condition. Optionally, the power converter includes a low load circuit responsive to the control circuit that selectively couples current to the output terminal during the low load condition.

Abstract: A limit-cycle oscillation (LCO) based switch-mode power supply (SMPS) response evaluation provides an effective mechanism for determining the characteristic response of an SMPS during normal operation of the SMPS. LCOs are induced in the SMPS loop by introducing a non-linearity in the loop, for example, decreasing the resolution of a pulse-width modulator that controls the SMPS switching circuit. The frequency and amplitude of the LCOs are determined and used to evaluate the characteristic response of the SMPS. In order to produce symmetric LCOs, which are more easily modeled, a zero-offset calibration circuit adjusts values provided to the pulse-width modulator, so that each value introduced during calibration is at the midpoint of a resolution cell. The frequency can be measured by counting between zero-crossings of the LCOs and the amplitude measured by capturing the LCO values immediately prior to each zero-crossing of a first difference of the LCO samples.

Abstract: Energy loss due to driving a plurality of power supply units simultaneously in a low-current region is prevented, and a more stable load current is obtained. The generation of a load current in a small-current region from a pilot arc current is handled solely by the power supply unit U1, the remaining (N?1) power supply units U2 through U4 are driven when the small-current region is exceeded, and a current that is the composite of all the currents is fed to the load, whereby a stable plasma arc power supply is obtained in which power consumption in the low-current region is reduced.

Abstract: Systems and methods presented herein generally provide for the controlled voltage of bipolar electrical energy through the selected operation of power stages. In one embodiment, a system that provides electrical energy includes a power supply and at least two power stages coupled to the power supply. The power stages are operable to selectively output electrical energy. By selecting the number of power stages which are turned on at a given time the total voltage of the electrical energy is controlled at that time. The system may further include one or more controllers coupled to the power stages to control selection of the power stages and thereby vary the output voltage.

Abstract: An apparatus and method are provided for suppressing the input current inrush for a voltage converter in a pre-charge stage. The voltage converter comprises a power input for receiving an input current, a power output for supplying an output voltage for a load, and an output capacitor connected to the power output. In a pre-charge stage, a current limiting device is connected between the power input and the output capacitor to limit the input current to flow therethrough, and a variable current limiting control circuit provides a control signal to the current limiting device to determine a variable maximum value for the input current.

Abstract: A multi-phase converter comprising a plurality of switching circuits each controlled by a phase controller and each providing a switched output voltage to an output node of the converter and wherein each switching circuit under control of the phase controller sequentially provides a switched output voltage to the output node at which an output voltage of the converter is developed; and a main control circuit including a clock circuit for providing a first clock signal to each of the switching circuits and a second lower frequency clock signal to a first of the phase controllers, each phase controller having a delay circuit controlled by the first clock signal to provide a delayed second clock signal for coupling to a next one of the phase controllers and in the case of a last one of the phase controllers, back to the main control circuit, whereby a plurality of sequentially delayed second clock signals is provided, one to each of the remaining phase controllers after the first phase controller to determine wh

Abstract: An apparatus, system, and method are disclosed for a low cost self-healing power supply. The invention includes a power supply that regulates a direct current (“DC”) regulated bus to maintain a regulated bus voltage under varying load conditions. The power supply includes at least one pulse-width modulated stage, wherein each pulse-width modulated stage includes at least two switches connected in parallel. Each switch includes a fuse connected in series with the switch that disconnects the switch in response to an over current condition sufficient to open the fuse. The power supply also includes a pulse-width modulator for each stage of the power supply that regulates a bus voltage controlled by the stage by sensing the controlled bus voltage and adjusting a switching duty cycle to regulate the controlled bus voltage to a target value. The pulse-width modulator for a stage provides a substantially identical switching duty cycle to each switch of the stage.

Abstract: An apparatus, system, and method are disclosed for a low cost fault-tolerant power supply. The invention includes a power supply that regulates a bus voltage under varying load conditions. The power supply includes at least one pulse-width modulated stage, where each pulse-width modulated stage includes at least two DC-to-DC converters connected and operating in parallel. Each converter includes a switch and a fuse connected in series where the fuse disconnects the switch in response to an over current condition sufficient to open the fuse. The power supply also includes a pulse-width modulator for each stage of the power supply that regulates a bus voltage controlled by the stage by sensing the controlled bus voltage and adjusting a switching duty cycle to regulate the controlled bus voltage to a target value. The pulse-width modulator for a stage provides a substantially identical switching duty cycle to each switch of the stage.

Abstract: An exemplary electronic device includes a controller, a first convertor, a second convertor, and a switching unit. The first convertor is configured for receiving a first voltage from an external power supply and converting the first voltage into a second voltage. The controller is coupled to the first convertor for generating a start signal when receiving the second voltage. The second convertor is connected to the controller for receiving the first voltage, converting the first voltage into a third voltage to power an operating unit of the electronic device, and converting the first voltage into a fourth voltage to power the controller when receiving the start signal. The switching unit is coupled to the controller and the first convertor for disabling the first convertor when the controller receives the fourth voltage. A related power supply unit is also provided.

Abstract: A direct current (DC) power supply for varying an output voltage according to a load current variation is disclosed. The DC power supply includes an alternating current(AC)/DC conversion unit converting commercial AC power into DC power, a DC/DC conversion unit converting a voltage level of the DC power and outputting output power, and a control unit controlling conversion of the voltage level of the fed-back DC power according to a variation in a load current of the output power from the DC/DC conversion unit.

Abstract: A system for the transmission of a direct current (DC) at a medium voltage level includes a system DC link configured to carry power from a source to a load module. The load module includes a DC-to-DC voltage step-down converter, a DC-to-AC inverter coupled downstream to the DC-to-DC voltage step-down converter, and a system AC link for carrying power from the load module to a motor system on a load side of the system AC link. The system is effective for delivering power over distances that are greater than 30 kilometers, and for delivery of power from an on-shore to offshore and sub-sea load.

Abstract: An inverter apparatus in which a control power source connected to a microcomputer or a peripheral circuit included in at least one of an inverter main body, a built-in option, and a parameter unit is provided in the inverter main body. The apparatus has an external-power-unit connector via which an external power unit can be connected to at least one of the inverter main body, the built-in option, and the parameter unit. The external power unit connected to the external-power-unit connector is configured to function as a power source that controls the microcomputer or the peripheral circuit included in at least one of the inverter main body, the built-in option, and the parameter unit.

Abstract: Systems and methods presented herein generally provide for the controlled voltage of electrical energy through the selected operation of power stages. In one embodiment, a system that provides electrical energy includes a power supply and at least two power stages coupled to the power supply. The power stages are operable to selectively output electrical energy. By selecting the number of power stages which are turned on at a given time the total voltage of the electrical energy is controlled at that time. The use of air core magnetic flux coupling provides a unique, easily insulated method to provide power to the voltage stages at different potentials relative to each other. The system may further include one or more controllers coupled to the power stages to control selection of the power stages and thereby vary the output voltage.

Abstract: The present invention is an AC/DC (alternating current to direct current) converter. The converter contains two semi-stages. One is the boost-flyback semi-stage that has excellent self-PFC property when operating in DCM even though the boost output is close to the peak value of the line voltage. Moreover, it allows part input power transferred to load directly through the flyback path so the power conversion efficiency is improved. The other one is the D/DC semi-stage that provides another parallel power flow path and improves the regulation speed.

Abstract: The present invention discloses a power supply device with low standby loss. The power supply device comprises a main power converter and an auxiliary power converter. The main power converter comprises a bulk capacitor. The main power converter connects parallelly with the auxiliary power converter. When the power supply device is in a standby mode, the main converter is turned off and the auxiliary converter provides the output to the outputting load and the bulk capacitor. Moreover, when the power supply device is in a normal mode, the main converter and the auxiliary converter together provide the output to an outputting load. Under a normal mode, the main converter provides most of the power and the auxiliary converter operates in a power-limited finite value such that the topology of the power supply device achieves a low standby loss.

Abstract: A power conversion device for receiving AC and/or DC power and providing a DC output includes: an AC input; a DC input; an output; AC-to-DC converter circuitry coupled to the AC input and to the output and configured to convert an AC voltage received at the AC input into a first output DC voltage and to provide the first output DC voltage to the output; and non-isolated DC-to-DC up/down converter circuitry coupled to the DC input and to the output and configured to directly convert an input DC voltage received at the DC input into a second output DC voltage that is one of a down-converted DC voltage that is lower than the input DC voltage and an up-converted DC voltage that is higher than the input DC voltage, the DC-to-DC up/down converter circuitry being further configured to provide the second output DC voltage to the output.

Abstract: This invention relates to a power module for a plug-in hybrid electric vehicle including an integrated converter having a rectifier changing AC to DC, a DC/DC converter changing from a first voltage to a second voltage, and a battery storing electrical energy. The integrated converter operates in three modes 1) AC plug-in charging mode, 2) boost mode supplying power from the battery to the electrical bus and 3) buck mode supplying power from the electrical bus to the battery. The integrated converter utilizes the same single inductor during each of the three operating modes to reduce cost and weight of the system.

Abstract: A method of estimating a temperature at a component of a device is provided. The temperature may be used to provide thermal load management of the device. In an exemplary embodiment, a switched mode power converter includes a power converter module and a switch that controls a switching cycle of the power converter module. A signal includes a bus voltage component and an oscillating signal component at least partially caused by switching of the switch. A switch instant of the switch can be isolated. A characteristic of the oscillating signal component of the signal can be detected. For example, a first peak voltage of the oscillating signal component can be detected after the switch instant. The temperature of the power converter module is estimated using the detected characteristic of the oscillating signal component. For example, the temperature can be estimated using the first peak voltage and best-fit curve parameters in solving a linear or a quadratic equation.

Abstract: A hold-up time extension controlling device for a power supply, that has a power factor correction circuit, a hold-up time extension circuit, a hold-up time controlling circuit, a storage capacitor and a DC to DC converter. The hold-up time extension controlling device has a switch and an auxiliary capacitor. When an AC power source is normal, the switch is controlled to turn on according to the power factor correction circuit to make the auxiliary capacitor connecting to the storage capacitor in parallel to averagely have a ripple current. When the AC power source is interrupted, the switch is controlled to turn off. At the time, the hold-up time extension circuit obtains a storage power of the auxiliary capacitor and then output to the DC to DC converter to keep the voltage of the storage capacitor at a preset voltage for a long time.

Abstract: The present invention relates to a digital current share apparatus and method for supplies in parallel wherein a digital current sharing is used to eliminate oscillations during current sharing by raising current in steps until the currents in power supplies in parallel are brought within a certain tolerance of one another.

Abstract: DC/DC converter has a transformer having primary coils connected to an input side and secondary coils connected to an output side. Each primary coil connects a full-bridge circuit comprising two switches on two legs, the primary coil being connected between the switches on each leg, each full-bridge circuit being connected in parallel wherein each leg is disposed parallel to one another, and the secondary coils connected to a rectifying circuit. An outer loop control circuit that reduces ripple in a voltage reference has a first resistor connected in series with a second resistor connected in series with a first capacitor which are connected in parallel with a second capacitor. An inner loop control circuit that reduces ripple in a current reference has a third resistor connected in series with a fourth resistor connected in series with a third capacitor which are connected in parallel with a fourth capacitor.

Abstract: Described herein is a system for generating electric power, comprising: an electric-power source (1) having a preferential point of operation; a double-stage inverter (3A, 3B), which transfers the energy from said source to an external a.c.-voltage electrical network (9); a block (5) for identification of the preferential point of operation, which supplies a reference signal according to the conditions of operation of the electric-power source and to the preferential point of operation of said source; a corrector block (10), provided for setting the parameter for control of the boost converter (3A) of the double-stage inverter (3A, 3B) as a function of the reference signal and of a signal of actual operation of said electric-power source, and for maintaining the source in the proximity of the preferential point of operation.

Abstract: An integrated circuit comprising a feedback terminal to receive a feedback signal. A voltage regulator has a feedback input to receive the feedback signal from the feedback terminal. The voltage regulator has a power output in communication with an output terminal. The voltage regulator being responsive to the feedback signal, to generate the power output. A voltage generator to generate a pull-up voltage having an amplitude greater than a DC voltage amplitude of the power output. The pull-up voltage being derived separately from the power output. A pull-up resistor in communication with the pull-up generator and the feedback input of the voltage regulator.

Abstract: A voltage source converter for conversion between dc and ac voltage includes at least two serially connected phase legs. The outputs of the conversion stages form phase outputs to be connected to a phase of an alternating voltage network via a respective transformer. The configuration of the conversion stages reduces the requirements on the individual components of the voltage source converter.

Abstract: A method and system to determine a battery mode of an integrated circuit device are presented. The battery mode is selected with respect to first and second direct current to direct current converter devices within the integrated circuit. A voltage is received at a single pin of the device. A battery mode is determined for the device based on the received voltage, and at least one of the direct current to direct current converter circuits is configured based on the determined battery mode.

Abstract: There is provided a power supply for AC/DC and DC/DC conversion which receives the DC power supplied from airplanes, vehicles and vessels as well as normal AC power, and converts the power to DC power and supplies it to portable electronic products. The power supply for AC/DC and DC/DC conversion includes an AC input 10, a DC input 20, a switch 30 for selecting AC input power or DC input power, a DC output 40, and a circuit used for AC/DC and DC/DC conversion 100 which converts the power input from the AC input or the DC input to DC power having predetermined values of current and voltage, and a secondary side of a transformer (TL) for AC/DC conversion inside the circuit for conversion serves as an inductor for performing DC/DC conversion.

Abstract: A polyphase converter circuit having p?3 phases (R, Y, B) and a converter circuit element provided for each phase (R, Y, B) is specified, each converter circuit element having a rectifier unit, a DC voltage circuit which is connected to the rectifier unit and an inverter unit which is connected to the DC voltage circuit. In addition, a first AC voltage output of each inverter unit forms a phase connection, and second AC voltage outputs of the inverter units are star-connected. In order to produce harmonics which are as low as possible with respect to the fundamental of the voltage and the current of an electrical AC voltage system which is connected on the input side to the converter circuit, n transformers are provided, each having a primary winding and m three-phase secondary windings, where n?2 and m?3.

Abstract: A power supply apparatus includes: a transformer which converts input power supplied to a primary winding to be induced to a secondary winding; a current detector which detects an output current of the secondary winding of the transformer; a voltage detector which detects an output voltage of the secondary winding of the transformer; a switch which adjusts the output voltage outputted by the transformer; and a controller which controls the switch to maintain output power obtained by multiplying the output current by output voltage, within a predetermined level.

Abstract: A multi-phase converter comprising a plurality of switching circuits each providing a switched voltage to an output node of the converter and wherein each switching circuit sequentially provides a switched output voltage to the output node at which an output voltage of the converter is developed; a clock circuit for providing a plurality of out of phase clock signals to the switching circuits to determine when each switching circuit provides the switched voltage to the output node; each switching circuit comprising first and second series connected switches connected across a DC voltage bus; further comprising a first circuit comparing a first signal proportional to a difference between the output voltage of the converter at the output node and a first reference voltage with a second signal comprising a ramp signal and for producing a pulse width modulated signal to control the on-times of the switches of the connected switching circuit; further comprising a second circuit comparing the first signal proportio

Abstract: A power supply circuit of an image display apparatus is provided. The power supply circuit uses a single DC-DC converter, and is capable of supplying low voltage when the image display apparatus is in standby mode, and supplying high voltage as required when the image display apparatus is in operating mode. As a result, power consumption and manufacturing costs are reduced.

Abstract: A method of providing power to a load is provided. A first series resonant converter is provided. A second SRC is operably coupled to the first SRC in a cascade connected arrangement. First and second zero voltage switching (ZVS)-assistance networks are operably coupled between the first SRC and the second SRC, such that the first and second ZVS-assistance networks are providing first and second ZVS-assistant currents flowing from each ZVS-assistance network to the cascade connected arrangement of SRCs. Power from a power source is received at the cascade connected arrangement of first and second SRCs, power from a power source. The cascade connected arrangement of first and second SRCs supplies an output voltage to the load in response to receiving power from the power source.

Abstract: Effective power regulation may be achieved for a field instrument that derives power from a communication signal. In particular aspects, a system and process for power regulation include the ability to receive a communication signal and adjust the voltage supplied to a power converter based on the current of the communication signal. The system and method also include the ability to convert power of the communication signal with the power converter.

Abstract: A method for controlling at least two series-cell based drives connected in parallel. The method comprises detecting a failed cell in one of the drives, inhibiting operation of the drive with the failed cell, determining a peak output voltage capability of the drive with the failed cell, communicating the peak output voltage capability to a master controller, and limiting a maximum voltage that each drive can apply to a motor. The method also comprises bypassing the failed cell and resuming operation of the drive with the failed cell after the motor voltage falls below the peak output voltage capability of the drive with the failed cell.

Abstract: A system and method for controlling cross current in an interleaved power converter system having a plurality of converter threads coupled in parallel includes collecting a feedback current from each thread and obtaining a normal current and a differential mode current for each thread, based on its respective feedback current. The normal current of each thread is regulated to a commanded thread normal current value via a respective normal current control loop based on d-q rotating frame parameters. A differential mode cross current of each thread is regulated to zero via a respective differential mode cross current control loop based on d-q rotating frame parameters; while a differential mode cross current DC offset of each thread is regulated to zero via a respective differential mode cross current control loop based on stationary frame parameters.

Abstract: A switch power supply with standby function is disclosed. The power supply can satisfy the need of the green environment protection. And a single ended green switch power supply IC or thick film or modular circuit design with standby function is disclosed, too. It comprises a standby power supply, a main power supply, a PFC device, and a supplemental circuit, wherein a remote control signal is transmitted to main control circuit in response to a main error signal to control main power supply. A method for preventing switch power current from overload and saturation is disclosed too. Finally, the present invention also provides a green power supply with standby function as well as its IC associated with digital processing highly qualified PFC, and a PC standard (such as ATX, ATX12, SSI) computer switch power supply.

Abstract: A 7-level wye-connected H-bridge converter that provides redundancy for continued operation when one bridge phase has failed and more particularly to a topology that includes multiple semiconductor H-bridges and a three-phase semiconductor mid-bridge. The converter may continue operation with failure of any bridge, as a three-phase, wye-connected H-bridge by bypassing the failed bridge. Individual bridges of the converter may be operated at different dc-bus voltages to maximize power output. The converter may employ synchronous gating signals for the semiconductor devices of the bridges, including a zero-current notch waveform for minimizing harmonic distortion of the output waveform.

Abstract: An architecture is described for digital multi-phase modulators (MPM) that leads to an efficient, high performance hardware realization. The combined modulator, switching phases and output filter can be viewed as a multi-level digital to analog converter with high power output, or a power D/A, and concepts used in D/A converters are leveraged to achieve high performance and hardware efficiency. The modulator can be split into three functional blocks including a decoder that determines how many phases are on at any time, a selector that determines which phases are on at any time, and a single high resolution module that is time shared among all phases. The resulting architecture scales favorably with a large number of phases, fs, facilitates fast update rates of the input command well above the single phase switching frequency and is compatible with a wide range of known DPWM techniques for the LSB module and resolution-enhancement techniques such as dithering or ?-? modulation.

Abstract: A method and an apparatus are used for power supply input connection.

Abstract: An electrical DC-to-AC power conversion apparatus is disclosed that is primarily intended for use with solar photovoltaic sources in electric utility grid-interactive applications. The invention improves the conversion efficiency and lowers the cost of DC-to-AC inverters. The enabling technology is a novel inverter circuit topology, where throughput power, from DC source to AC utility, is processed a maximum of 1½ times instead of 2 times as in prior-art inverters. The AC inverter output configuration can be either single-phase, split-phase or poly-phase.

Abstract: A matrix converter for converting a polyphase alternating current into a desired alternating output current includes at least two stages; a plurality of controllable bidirectional switches, converts m phases of the polyphase alternating current into alternating output current with n (n<m) phases of a load; and a controllable bidirectional switch controlling each phase of the polyphase alternating current in at least one stage of the converter.

Abstract: A power supply apparatus for use with arc-utilizing apparatuses includes a plurality of power supply blocks of the same capacity. Each power supply block includes an input-side rectifying circuit, an inverter, a transformer, and an output-side rectifying circuit. The inverter is controlled by a control circuit in such a manner that high-frequency current flowing the inverter or current flowing through the output-side rectifying circuit can correspond to a reference signal provided by a reference signal generator. The outputs of the output-side rectifying circuits of the power supply blocks are connected in parallel with each other. The values of the reference signals generated by the reference signal generators are made always equal by the action of equipotential lines.