Abstract: Power conversion systems and methods are presented for detecting filter capacitor resonance conditions in a power conversion system in which filter currents are measured and filtered using a bandpass filter, and one or more computed mean, RMS, and/or Fourier transform values are computed based on the filtered value(s). The computed measurement value or values are compared with a predetermined threshold and a suspected filter capacitor resonance condition is selectively identified based on comparison result.

Abstract: The present invention provides a power conversion device in which an on-pulse bias voltage and a neutral-point bias voltage do not interfere with each other. A power conversion device 1 of the present invention has a polarity judgment section 8 that judges a polarity of a neutral-point bias voltage VNPC calculated by a neutral-point potential fluctuation suppression control section 4 of a voltage command value control circuit 3, then on the basis of this polarity of the neutral-point bias voltage VNPC, selects a polarity of an on-pulse bias voltage VMPC by an on-pulse control section 5. With this control, it is possible to prevent for the polarities of the neutral-point bias voltage VNPC and the on-pulse bias voltage VMPC from being different then prevent for the both bias voltages from interfering with each other.

Abstract: There is provided a device including: an inverter 5 including switching elements 51-52 for outputting a U-phase voltage and switching elements 53-54 for outputting a W-phase voltage; midpoint capacitors 31-32; a midpoint stabilizer 2 configured to regulate a power storage amount of each of the midpoint capacitor 31 and the midpoint capacitor 32; and a controller 7 configured to control the switching elements 51-54 so as to supply a desired U-phase voltage and a desired W-phase voltage based on voltages between the U-phase voltage line and the neutral line and the voltage between the W-phase voltage line and the neutral line, and control the midpoint stabilizer 2 so as to adjust the midpoint potential in the O phase based on the condition of the midpoint potential in an O phase at a connecting point between the midpoint capacitor 31 and the midpoint capacitor 32.

Abstract: To suppress a decline in the control accuracy of an applied voltage associated with an increase in quantum noise, and to increase the control accuracy of a motor speed. When generating a driving voltage signal supplied to a motor from a driving command signal, a motor-driving voltage control device reduces the gradation level and performs noise-shaping modulation before performing PWM modulation. Reducing the gradation level allows the degree of gradation of the driving voltage signal to be within the resolution range of the PWM modulation, and thus PWM modulation can be performed even when the driving voltage signal has a high frequency. Noise-shaping modulation reduces the level of quantum noise near the low frequency range by causing the quantum noise due to digitization, included in the driving voltage signal, to be biased toward the high frequency range side.

Abstract: A power transmitting device includes a resonance circuit, a first signal generating unit, and a second signal generating unit. The resonance circuit is used in non-contact power transmission. The first signal generating unit is connected to one end of the resonance circuit, and generates, with the use of a switching system, a first high-frequency signal including one or more harmonic components. The second signal generating unit is connected to an other end of the resonance circuit, and generates, with the use of a switching system, a second high-frequency signal including a specific harmonic component. The first high-frequency signal is adjusted in pulse width and input to the one end of the resonance circuit, and the second high-frequency signal is adjusted in pulse width and phase difference from the first high-frequency signal and input to the other end of the resonance circuit.

Abstract: It is presented a DC/DC converter for converting power between a first DC connection comprising a first positive terminal and a first negative terminal, and a second DC connection comprising a second positive terminal and a second negative terminal. The DC/DC converter comprises: a first multilevel converter and a second multilevel converter connected serially between the first positive terminal and the first negative terminal, wherein the second positive terminal is connected to a point between the first multilevel converter and the second multilevel converter; and a first filter connected between an AC terminal of the first multilevel converter and an AC terminal of the second multilevel converter, wherein the first filter comprises a capacitor and an inductor.

Abstract: A method for the operational control of an inverter designed for DC/AC voltage conversion that has at least one direct-voltage input and that can be connected to a power supply grid via at least one alternating-voltage output, the inverter being involved in a power flow interaction with the grid in such a manner that, during operation of the inverter, a leakage current IA can occur, wherein the leakage current IA is controlled in the operational control.

Abstract: A power conversion apparatus includes a power converter, an LC filter, and a controller. The power converter is disposed between an AC power source and a load. The LC filter is disposed between the AC power source and the power converter. The controller controls the power converter to perform power conversion control between the AC power source and the load. The controller includes a command generator, an oscillation component acquirer, a regulator, and an actuator. The command generator generates an input current command including a command of an input current of the power converter. The oscillation component acquirer acquires an oscillation component of a current flowing through a capacitor of the LC filter. The regulator regulates the input current command based on the oscillation component acquired by the oscillation component acquirer. The actuator controls the power converter based on the input current command regulated by the regulator.

Abstract: A method and apparatus for generating AC power. In one embodiment, the apparatus comprises a DC/AC inversion stage capable of generating at least two of a single-phase output power, a two-phase output power, and a three-phase output power; and a conversion control module, coupled to the DC/AC inversion stage, for driving the DC/AC inversion stage to (i) generate the single-phase output power while an input power is less than a first threshold, and (ii) operate in burst mode while the input power satisfies a burst mode threshold.

Abstract: A discharge lamp lighting device includes: a DC power supply unit that outputs a DC current; an inverter that sequentially generates, from the DC current output from the DC power supply unit, a current pulse whose current direction alternately changes to supply the current pulse to a discharge lamp; and a control unit that controls operations of the DC power supply unit and the inverter to adjust a waveform of the current pulse to be supplied to the discharge lamp, wherein the control unit changes a pulse width of the current pulse every pulse.

Abstract: A power converter, control apparatus and methods are presented for driving a permanent magnet motor or other load through a sine wave filter and a transformer, in which inverter output current is controlled using a current-frequency relationship to convert a desired frequency or speed value to a current setpoint, and the inverter output current is regulated to the current setpoint using a control algorithm with a bandwidth below the resonant frequency of the sine wave filter.

Abstract: A load control device includes an input and an output connectable to an AC source and an AC load, respectively, with one or more supply lines each corresponding to a phase in the load connecting the input and output. Line-side switches are connected between a line terminal and load terminal, and floating-neutral side switches are connected to the load terminal at one end and at a common neutral connection at another end. A controller determines a direction of current flow on each of the supply lines, determines a switching pattern for each of the line-side switches and each of the floating-neutral side switches based on the determined direction of current flow, and causes each of the line-side switches and floating-neutral side switches to operate in an On condition or an Off condition according to the determined switching pattern, such that a controlled uninterrupted current is provided to the AC load.

Abstract: A power conversion device includes an inverter that drives a motor; a fin that cools down the inverter; a first core including a through hole that allows passage of a positive side conductor that connects a power supply system and the inverter and a negative side conductor that grounds the inverter; a ground conductor that grounds the fin; a ground conductor that grounds a motor yoke via a capacitor; and a ground conductor including one end that is connected to the negative side conductor or the ground conductor and the other end that is grounded.

Abstract: An apparatus and method for controlling the delivery of power from a DC source to an AC grid includes an inverter configured to deliver power from the unipolar input source to the AC grid and an inverter controller. The inverter includes an input converter, an active filter, and an output converter. The inverter controller includes an input converter controller, an active filter controller and an output converter controller. The input converter controller is configured to control a current delivered by the input converter to a galvanically isolated unipolar bus of the inverter. The output converter is configured to control the output converter to deliver power to the AC grid. Additionally, the active filter controller is configured to control the active filter to supply substantially all the power that is deliver by the output controller to the AC grid at a grid frequency.

Abstract: The described embodiments relate generally to electronic components and more specifically to a capacitor array that can increase component density on a printed circuit board and reduce a distance to a ground plane. An array of capacitors can be formed by coupling a group of capacitors on their sides interspersed with interposer boards. The resulting configuration can increase component density and reduce an amount of resistance and effective series inductance between a set of power decoupling capacitors and an integrated circuit.

Abstract: A semiconductor device includes: a semiconductor substrate; a diode-built-in insulated-gate bipolar transistor having an insulated-gate bipolar transistor and a diode, which are disposed in the substrate, wherein the insulated-gate bipolar transistor includes a gate, and is driven with a driving signal input into the gate; and a feedback unit for detecting current passing through the diode. The driving signal is input from an external unit into the feedback unit. The feedback unit passes the driving signal to the gate of the insulated-gate bipolar transistor when the feedback unit detects no current through the diode, and the feedback unit stops passing the driving signal to the gate of the insulated-gate bipolar transistor when the feedback unit detects the current through the diode.

Abstract: According to one aspect, embodiments of the invention provide a method of operating a UPS system having a first UPS and a second UPS coupled in parallel to provide output power to a load from a power source, each of the first UPS and the second UPS having an inverter and having a bypass switch, with each UPS configured to operate in one of an inverter mode in which output power is derived from the power source through the inverter, and a bypass mode in which output power is derived from the power source bypassing the inverter, the method comprising powering on the first UPS and the second UPS in the inverter mode of operation, designating one of the first UPS and the second UPS as a master UPS, and controlling the bypass switch of the first UPS and the bypass switch of the second UPS using the master UPS.

Abstract: A noise filter disclosed herein is configured to suppress a common mode voltage that is generated in cables connected to an electric power converter. The noise filter includes: detecting capacitors connected to the cables, respectively, and configured to detect the common mode voltage; an operational amplifier having a positive input terminal via which the common mode voltage detected by the detecting capacitors is inputted; an emitter follower circuit having an input terminal connected to an output terminal of the operational amplifier and having an output terminal connected to a negative input terminal of the operational amplifier; and a transformer configured to apply a compensating voltage to each of the cables by applying a voltage at the output terminal of the emitter follower circuit to each of the cables in opposite phase.

Abstract: A motor control device includes a rectifier, an inverter connected to the rectifier via the DC link, a power failure detecting unit detecting power failure, a voltage detecting unit detecting a DC voltage at the DC link, an electric storage unit storing DC power, a charging unit that can make charging by boosting to a voltage higher than the DC voltage, a discharging unit discharging DC power, a resistance discharge device that performs resistance discharging of DC power at the DC link when the DC voltage after power failure is equal to or higher than a predetermined start level and that does not perform resistance discharging when the DC voltage is equal to or lower than a predetermined stop level, and a discharging operation determining unit operating the discharging unit when the DC voltage at the DC link after power failure is equal to or lower than a predetermined threshold.

Abstract: The present invention relates to a common mode filter and a method of manufacturing the same. In order to implement a common mode filter with low shrinkage, high substrate sintered density, and high strength, the present invention provides a common mode filter including: a lower substrate; an insulating layer having a conductor pattern inside and provided on the lower substrate; an upper substrate provided on the insulating layer; and a ferrite core made of ferrite and provided in the center of the insulating layer, the lower substrate, and the upper substrate by penetrating the insulating layer, the lower substrate, and the upper substrate, and a method of manufacturing the same.

Abstract: This disclosure relates to a variable speed drive for driving a single phase motor. The variable speed drive generates enhanced motor voltages including harmonic components configured to reduce torque pulsations.

Abstract: Disclosed is a grid-connected inverter and a method for filtering AC output thereof. The grid-connected inverter includes an AC output filter which includes two or more switchable filtering modules, with the power capacity of each filtering module corresponding to a different output power of the grid-connected inverter; a monitoring module which is used to perform realtime monitoring on voltage and current outputted by the grid-connected inverter; and a control circuit which is used to calculate an output power grade of the grid-connected inverter according to the voltage and the current monitored by the monitoring module and control switching to the filtering module having a corresponding power capacity according to the power grade, the power grade being selected from a plurality of power grades which are divided according to power capacities of the filtering modules.

Abstract: A system for controlling photovoltaic electricity production equipment having photovoltaic modules each equipped with a DC/DC microconverter connected to a DC bus, a DC bus manager, and an inverter for converting the direct current from the photovoltaic panels into alternative current intended for an electrical distribution network. Power is injected into the DC bus when the voltage of the DC bus is less than a minimum voltage until the minimum voltage is reached. Each of the microconverters injects a maximum power from the photovoltaic modules into the DC bus when the voltage of the DC bus is between a first voltage and a second voltage. The injecting of power from the photovoltaic modules into the DC bus is stopped when the voltage of the DC bus is less than a low threshold voltage or greater than a high threshold voltage.

Abstract: A contactless power supply has a dynamically configurable tank circuit powered by an inverter. The contactless power supply is inductively coupled to one or more loads. The inverter is connected to a DC power source. When loads are added or removed from the system, the contactless power supply is capable of modifying the resonant frequency of the tank circuit, the inverter frequency, the inverter duty cycle or the rail voltage of the DC power source.

Abstract: An exemplary method and an apparatus implementing the method for an arrangement having a three-phase, multi-level inverter, an output LCL-filter connecting the inverter to a grid, and a virtual-ground connection between the LCL-filter and the neutral point of the DC-link. The method includes determining a zero-sequence component of an LCL-filter inverter-side current, calculating a zero-sequence damping and balancing voltage term based on the LCL-filter inverter-side current zero-sequence component and voltages over the two halves of the DC-link, and adding the zero-sequence damping and voltage balancing term to the output voltage reference.

Abstract: A power conversion device according to the aspects of the present technique is presented. The device includes a first converter and a second converter operatively coupled to the first converter. Moreover, the device includes a phase leg operatively coupled between the first converter, the second converter, where the phase leg includes a first unidirectional switch, a second unidirectional switch operatively coupled to the first unidirectional switch, and a first bidirectional switch, where a first end of the first bidirectional switch is operatively coupled to at least one of the first unidirectional switch and the second unidirectional switch.

Abstract: A power conversion apparatus is applied to a filter circuit. A reactor of the filter circuit includes a vertical pair of yoke iron cores, in each of which a thin strip of magnetic material is rolled in a toroidal manner and magnetic leg iron cores having respective phases being a pillar formed of thin-strip shaped magnetic material, being provided on a symmetrical position on a circumference with respect to a center of the yoke iron cores, connecting the vertical pair of the yoke iron cores, and providing a coil. The reactor also includes magnetic leg iron cores for zero-phase impedance having the respective phases, each having a rectangular parallelepiped shape in which a plurality of thin strips made of magnetic material are laminated in a direction toward a periphery from the center of the yoke iron cores and being provided between the magnetic leg iron cores.

Abstract: When RF power is supplied from an RF generator to a load via a power supply unit, (a) the internal impedance of the RF generator is made lower than the characteristic impedance of the power supply unit, and (b) the load-end voltage is increased by selecting the electrical length LE of the power supply unit, which connects between the RF generator and the load to supply RF power, so that the electrical length LE has a predetermined relation with the fundamental wavelength ? of the RF AC. More specifically, the electrical length LE of the power supply unit is selected in such a way that, when the load end, which is the input end of the load, is in an open state, the electrical length LE is (2n?1)·(?/4)?k·??LE?(2n?1)·(?/4)+k·? (n is an integer, k is {??2·cos?1(1/K)}/(4?)) with respect to the fundamental wavelength ? of the RF AC.

Abstract: A DC-to-AC power conversion system is provided to convert a DC input voltage into an AC output voltage, which mainly includes a bridge switching circuit, an auxiliary switch circuit, and a control circuit. The bridge switching circuit has a first power switch, a second power switch, a third power switch, and a fourth power switch. The auxiliary switch circuit has a fifth power switch, a sixth power switch, a seventh power switch, and an eighth power switch. The control circuit produces a complementary switching signal pair to control the first and fourth power switches and the second and third power switches, respectively. In addition, the control circuit produces a complementary level signal pair to control the sixth and seventh power switches and the fifth and eighth power switches, respectively.

Abstract: A contactless power supply has a dynamically configurable tank circuit powered by an inverter. The contactless power supply is inductively coupled to one or more loads. The inverter is connected to a DC power source. When loads are added or removed from the system, the contactless power supply is capable of modifying the resonant frequency of the tank circuit, the inverter frequency, the inverter duty cycle or the rail voltage of the DC power source.

Abstract: An arrangement transmits power between a DC power line and an AC power line carrying a voltage having a number of phases. The arrangement includes a number of transformers, one for each phase and a number of power transfer modules, one for each phase, connected in series between the DC power line and ground, where each module includes a first branch including series connected converter cells and a second branch including series connected switching elements. The primary winding of a transformer is connected to a corresponding AC phase conductor of the AC power line and the secondary winding is connected between a midpoint of the first branch and a midpoint of the second branch of a corresponding power transfer module.

Abstract: An electrical on-board network of a vehicle, having at least two power circuits and an electrical machine allocated to a drive of the vehicle. The electrical machine has at least two phase systems, connected to a respective inverter, and that at least one of the phase systems is capable of being electrically connected to at least one of the power circuits via the associated inverter. A method for operating an electrical on-board network of a vehicle is also described.

Abstract: A method is provided for balancing voltages of a DC link of a multi-level inverter, where the DC link is divided into two halves by a neutral point connection. The method includes injecting a periodic common-mode voltage injection signal to a common-mode voltage reference and a periodic power injection signal to a power reference of the inverter. The power injection signal has the same frequency as the common-mode voltage injection signal. A phase shift between the common-mode voltage injection signal and the power injection signal is constant. The amplitude of at least one of the common-mode voltage injection signal and the power injection signal is controlled on the basis of a difference between voltages over the two halves of the DC link. An apparatus is also provided for implementing the method.

Abstract: A system includes power electronics inverters connected in a network. The power electronics inverters can utilize measurements at local terminals, without a need to exchange information between other power electronics inverters.

Abstract: An arrangement which includes two or more energy storage units for electrical energy connected in series, and two or more balancing resistor units. Each balancing resistor unit is connected in parallel with one of the energy storage units. The arrangement also includes means for determining a voltage over all of the series-connected energy storage units and means for determining the energy storage unit voltages between poles of the energy storage units. One or more of the balancing resistor units include a base resistor unit and a control resistor unit connected in series and a switching device connected in parallel with the control resistor units.

Abstract: A system for providing, from a direct current (DC) voltage source, an alternating current (AC) to an electrical grid outputting a grid voltage, the system including: a transformer for coupling to the DC voltage source through a first switch controlled by a first control signal, and configured to provide a converted voltage based on a DC voltage; a rectifier coupled to the transformer, and configured to generate an envelope voltage of the converted voltage; a plurality of switches coupled to the rectifier to receive the generated envelope voltage of the converted voltage, the plurality of switches being controlled by a plurality of control signals, respectively, and configured to generate the AC from the generated envelope voltage of the converted voltage; and control apparatus coupled to the first switch and the plurality of switches, and configured to provide, based on the grid voltage, the first control signal and the plurality of control signals.

Abstract: A current control unit takes a deviation between a current command value and a current flowing through an inverter of a power conversion device, and controls the inverter based on the deviation. A harmonic sensing part receives input of an output current of an AC filter, and outputs a predetermined order harmonic of the input current in a direct current value form. A disturbance observer estimates the disturbance of the harmonic based on the output current and a coefficient defined as an inverse function of a transfer function from harmonic suppression current command value to filter output current detection value. A harmonic suppression control unit takes the deviation between the estimated harmonic disturbance and a disturbance command value that suppresses the disturbance, and calculates a harmonic suppression current command value. The harmonic suppression current command value is superimposed on the current command value of the current control unit.

Abstract: A voltage control rate of an inverter has a DC component and an AC component. This AC component has a frequency which is six times a fundamental frequency of an AC voltage outputted by the inverter. Even when there are not only a fifth-order harmonic component but also a seventh-order harmonic component of a load current, a ratio between the magnitude of the AC component and the DC component can be appropriately set.

Abstract: The invention comprises a high frequency inductor filter apparatus coupled with an inverter yielding high frequency harmonics and/or non-sixty Hertz output. For example, an inductor/converter apparatus is provided that uses a silicon carbide transistor to output power having a carrier frequency, modulated by a fundamental frequency, and a set of harmonic frequencies. A filter, comprising an inductor having a distributed gap core material and optional magnet wires, receives power output from the inverter/converter and processes the power by passing the fundamental frequency while reducing amplitude of the harmonic frequencies.

Abstract: The invention comprises a high frequency inductor filter apparatus coupled with an inverter yielding high frequency harmonics and/or non-sixty Hertz output. For example, an inductor/converter apparatus is provided that uses a silicon carbide transistor to output power having a carrier frequency, modulated by a fundamental frequency, and a set of harmonic frequencies. A filter, comprising an inductor having a distributed gap core material and optional magnet wires, receives power output from the inverter/converter and processes the power by passing the fundamental frequency while reducing amplitude of the harmonic frequencies.

Abstract: A power conversion circuit converting DC electric power into AC electric power and sending the AC power to an inductive load, includes a first switching device connected to the DC power supply; a second switching device connected to the DC power supply; a first inductor provided between the first switching device and the inductive load; a second inductor provided between the second switching device and the inductive load; and a clamping diode connected between a first connection point between the first switching device and the first inductor, and a second connection point between the second switching device and the second inductor. When the first and second switching devices are turned off, a current flows through the second diode, clamping diode, first inductor and inductive load to completely flow out a current in the first inductor, and then a current flows through the second diode, second inductor and inductive load.

Abstract: An embodiment of the present invention is directed to an integrated electromagnetic compatibility (EMC) filter and power line communication (PLC) interface. The EMC filter and PLC interface comprises a first filter winding and a second filter winding configured as a common mode choke; and a two-part winding on the common mode choke, wherein the two-part winding comprises (i) a first winding coupled proximate the first filter winding and (ii) a second winding coupled proximate the second filter winding, wherein the first winding and the second winding have an equal number of turns, and wherein phasing of the first winding is reversed with respect to the second winding.

Abstract: A converter control device comprises: a voltage-zero-cross detection unit detecting zero cross of the alternate-current voltage and outputting a voltage zero-cross signal; a power-source-current detection unit detecting a power source current of the alternate-current power source; a bus-line-voltage detection unit detecting a bus-line voltage between terminals of the smoothing capacitor; a PWM-signal generation unit generating a PWM-signal for on/off-controlling the switching unit, based on the power-source current, the bus-line voltage and a bus-line-voltage command value as a target voltage of the bus-line voltage; a power-source voltage-state detection unit detecting a signal state of the alternate-current voltage based on the voltage zero-cross signal; and a fundamental-switching-frequency selection unit selecting a fundamental switching frequency of the PWM-signal based on the signal state of the alternate-current voltage.

Abstract: A motor driving system including command value output means configured to output an analog value according to a rotation speed command; a first power line having first switching means; a drive circuit, to which power is supplied via the first switching means and the first power line, driving a motor supplying rotation based on the analog value; and switching control means configured to make the first switching means nonconductive when the analog value is smaller than a first predetermined value, and independent of the command value output means.

Abstract: A 1, 2 or 3-phase DC to AC converter system for reducing the cost of solar energy installations achieves cost reduction by eliminating low-frequency power transformers. One DC input polarity is selectively switched to an output terminal when the instantaneous AC output from a second output terminal is desired to be of the opposite polarity, while the other DC input polarity is used to form an approximation to a segment of a sine wave of the desired polarity at the second output terminal. A common-mode AC signal is thereby created on the balanced DC input lines at a frequency which is a multiple of 1, 2 or 3 times the AC output frequency and which is useful for detecting ground faults in the DC circuit.

Abstract: We describe a photovoltaic power conditioning unit comprising: both dc and ac power inputs; a dc link; at least one dc-to-dc converter coupled between dc input and dc link; and a dc-to-ac converter coupled between dc link and ac output. The dc-to-dc converter comprises: a transformer having input and output windings; an input dc-to-ac converter coupled between dc input and input winding; and an ac-to-dc converter coupled between output winding the dc link. The output winding has a winding tap between the first and second portions. The ac-to-dc converter comprises: first and second rectifiers, each connected to a respective first and second portion of the output winding, to the dc link and winding tap; and a series inductor connected to the winding tap. Rectifiers are connected to the winding tap of the output winding via the series inductor wherein the series inductor is shared between the first and second rectifiers.

Abstract: The present invention relates to a power converter with low common mode noise, at least comprising: a ground terminal, a power converting unit, a capacitor unit of common DC bus, a filtering capacitor unit, a filtering inductor unit, and a compensation unit. In the present invention, a filtering inductor unit including three primary windings and three auxiliary windings is used for making the power converting unit couple to three phase terminals of an external electrical apparatus. Moreover, the three auxiliary windings are further formed a compensation circuit by way of being connected with the compensation unit, such that the engineer is able to easily and effectively suppress the common mode noise occurring near the resonant frequency of the power converting apparatus through selecting a suitable turns ratio of the primary windings and the auxiliary windings.

Abstract: The present disclosure discloses a converter system, which at least includes the first and second back-to-back converters. The first back-to-back converter includes a first rectifier module and a first inverter module. The first rectifier module is used to convert a first AC voltage to a first DC voltage. The first inverter module is used to convert the first DC voltage to a second AC voltage. The second back-to-back converter includes a second rectifier module and a second inverter module. The second rectifier module is used to convert the first AC voltage to a second DC voltage. The second inverter module is used to convert the second DC voltage to the second AC voltage. The converter system can suppress the circular current through the synchronous operation of the first and second rectifiers or the synchronous operation of the first and second inverters.

Abstract: Disclosed herein is a method of manufacturing a noise removing filter, including preparing at least one conductive pattern, an insulating layer for covering the at least one conductive pattern, and a lower magnetic body including input/output stud terminals for electrically inputting and outputting electricity to and from the at least one conductive pattern; disposing a recognizable portion on upper surfaces of the input/output stud terminals; disposing an upper magnetic body on the recognizable portion and the insulating layer; polishing the upper magnetic body; and removing the recognizable portion such that a level of an upper surface of the upper magnetic body is higher than levels of the upper surfaces of the input/output stud terminals.

Abstract: A power supply unit for a press machine having a converter (converter circuit) connected to a commercial AC power supply, and an inverter (inverter circuit) connected to a press motor, includes an electrical energy bank, an inrush prevention circuit, an inrush prevention instruction signal generation section, and a contactor switch section, wherein contactors of the inrush prevention circuit are switched from on ON state to an OFF state and inrush prevention resistors of the inrush prevention circuit are connected to AC phase current paths on condition that the inrush prevention instruction signal generation section has generated and output an inrush prevention instruction signal (Sres) during press operation.