Abstract: Operating a gate driver. At least one example is a method of operating the gate driver, the method comprising: de-asserting a drive-low terminal of the gate driver; starting a single timer within the gate driver; and after expiration of the single timer asserting a drive-high terminal of the gate driver responsive to assertion of an in-high terminal of the gate driver; and then de-asserting the drive-high terminal; starting the single timer; and after a second expiration of the single timer asserting the drive-low terminal responsive to assertion of an in-low terminal of the gate driver.

Abstract: A computer sound card includes a power supply noise isolation circuit for reducing ground plane noise generated during application of heavy electrical loads to the power supply, such as loads presented by computer GPUs. The power supply isolation circuit isolates the output ground from the ground presented from the power supply to the isolation circuit input. The isolation circuit in one embodiment includes switching circuitry and a transformer to reduce the power supply ripple noise that might otherwise be introduced by the power supply into an amplifier such as a microphone preamp. In some embodiments a differential amplifier stage is added to the output of the microphone preamp stage to further reduce noise, such as common mode noise.

Abstract: A circuit arrangement and an electrical system, where in the circuit arrangement, an output terminal of a current limiting control circuit is connected to a control input of a semiconductor switch via a resistor (RG), and a gate driver is connected to the control input of the semiconductor switch via the gate resistor RG and to the resistor (R). The current limiting control circuit is configured to change its output impedance at the output terminal in order to control the semiconductor switch. A source terminal of the semiconductor switch is connected to a reference potential (GND) of the circuit arrangement, and the semiconductor switch is configured so as to set a current (I) in a circuit between an electrical power source and a load. A first inductor (L1) and a second inductor (L2) are connected in series within the circuit.

Abstract: A support insulator includes a conductive member, an insulating member, and an attachment portion. Busbars included in a main circuit are attachable to the conductive member. The conductive member electrically connects the busbars to each other. The insulating member is attachable to a fixed frame, and is disposed over an outer surface of the conductive member to insulate the conductive member and the busbars from the fixed frame. An electronic component included in the main circuit is attachable to the attachment portion.

Abstract: A power conversion device includes two lower arm switching elements connected in parallel to each other and a lower arm driver circuit that drives the two lower arm switching elements. The two lower arm switching elements respectively include gate terminals and detection terminals used to detect counter-electromotive forces. The power conversion device includes a common connection line that connects the two detection terminals to each other and connects the two detection terminals to an addition circuit of the lower arm driver circuit. A combined electromotive force is transmitted via the common connection line.

Abstract: Provided is a control unit of a power conversion device configured to select, in each first set cycle, a first target switching element and a second target switching element from a plurality of switching elements connected in parallel to each other. The control unit performs control so that, at a time of a turn-on operation of a switching circuit, a turn-on start time of the first target switching element is earlier by a first set time period than a turn-on start time of another switching element that is not the first target switching element. The control unit performs control so that, at a time of a turn-off operation of the switching circuit, a turn-off start time of the second target switching element is later by a second set time period than a turn-off start time of another switching element that is not the second target switching element.

Abstract: This command generation device generates a control command for a power conversion device which converts DC power outputted by a DC power supply device to AC power and supplies the same to a bus, and which converts AC power from the bus to DC power and supplies the same to the DC power supply device.

Abstract: A power converter apparatus comprises a set of switching elements communicatively coupled with a set of gate drive circuits. Each gate drive circuit is configured to provide a respective drive signal to a corresponding switching element, each switching element being switchably responsive to the respective drive signal. The apparatus includes a controller module configured to control an output state of the power converter, and selectively change one of a respective gate resistance and a respective gate current of a corresponding subset of the gate drive circuits based on the output state of the power converter.

Abstract: A controller of a power conversion device including a power converter connected between a direct current (DC) power supply and an alternating current (AC) power supply, includes: a damping control term calculation unit configured to calculate a value of pulsation of a DC voltage applied between the DC power supply and the power converter, or pulsation of a DC current flowing between the DC power supply and the power converter; and a current control unit configured to output, to the power converter, a command value for adjusting the power of the power converter so that a pulsation component corresponding to the pulsation value calculated by the damping control term calculation unit is reduced in accordance with a command value based on the value calculated by the damping control term calculation unit. The power conversion device can reduce resonance without including a damping resistor.

Abstract: A power converter includes a pair of series connected switches and circuitry. The circuitry includes another switch and an optocoupler that activates responsive to changes in current through one of the series connected switches exceeding a predefined threshold. Activation of the optocoupler causes the another switch to conduct and reduce a gate voltage of the one of the series connected switches to reduce the changes in current through the one of the series connected switches.

Abstract: A semiconductor module includes a case accommodating a semiconductor element inside and being entirely molded by a resin, a first terminal placed on a top portion of the case and being a terminal to which a bus bar being a flat and elongated metal conductor is to be attached, a second terminal provided on the top portion of the case and being adjacent to the first terminal, and a rib provided between the first terminal and the second terminal. The rib includes a protrusion protruding toward the bus bar.

Abstract: The present disclosure provides a power supply control circuit and control method for a switching power supply system. The control circuit includes: a power transistor and current sampling module, a voltage common collector (VCC) charging management module, a switch module, and a voltage regulator clamping module. The power transistor and current sampling module includes: a main switch high-voltage power transistor, a power transistor driver, an auxiliary sampling high-voltage transistor, and a current sampling resistor. The switch module includes a first switch, a second switch, a third switch, and a fourth switch. The present disclosure realizes time-division multiplexing and seamless transition through a reasonable timing of the switch module, thereby enabling multiplexing of high-voltage devices reducing demands for high-voltage processes, saving chip costs, and reducing design difficulty.

Abstract: A converter device has a converter that has power semiconductor switches and has a control device that is designed to drive the power semiconductor switches. The control device is designed to drive the power semiconductor switches so that electrical switching losses occurring in the converter are reduced during use.

Abstract: An electrical power conversion device, a function triggering circuit for the electrical power conversion device, and a function triggering method for the electrical power conversion device are provided. The function triggering circuit is coupled between the secondary side of the transformer and the control module and includes a current detection circuit, a delay circuit and a switching circuit. The current detection circuit senses the secondary side of the transformer to generate a detection signal of delay. Before steady-state duty of the transformer, the delay circuit causes an initial level to be higher than an internal level. After steady-state duty of the transformer, the switching circuit selectively generates a function triggering signal according to the detection signal. The function triggering signal is for triggering the control module to carry out an overcurrent protection operation.

Abstract: An alternating current AC to direct current DC converting circuit for a turbine generator is provided that comprises an active AC/DC converter having a controllable output voltage level having an input for receiving alternating current electrical power from a turbine generator and an output for providing direct current electrical power to an electrolysis system for electrolysis of water. The AC to DC converter further comprises an oscillator for generating an alternating current auxiliary signal and a summation circuit for adding the alternating current signal to the output of the active AC DC converter. By adding an AC component to the DC output of the active AC DC converter, electrolysis cells in the electrolysis module connected to the AC DC converting circuit have been proven to operate more efficiently. The amplitude of the alternating current auxiliary signal is preferably less than the output voltage of the active AC/DC converter.

Abstract: A circuit for decoding a pulse width modulated (PWM) signal generates an output signal switching between a first and second logic values as a function of a duty-cycle of the PWM signal. Current generating circuitry receives the PWM signal and injects a current to and sinks a current from an intermediate node as a function of the values of the PWM signal. A capacitor coupled to the intermediate node is alternatively charged and discharged by the injected and sunk currents, respectively, to generate a voltage. A comparator circuit coupled to the intermediate node compares the generated voltage to a comparison voltage and drives the logic values of the output signal as a function of the comparison.

Abstract: An apparatus may include a group of distributed-input series-output (DISO) converters, each of which are actively controlled by a common maximum power tracking (MPT) controller. The common MPT controller is configured to actively control one of the DISO converters in the group of DISO converters to update a present group-peak power voltage of the one DISO converters while remaining DISO converters in the group of DISO converters are controlled to hold most recently grouped peak power voltages updated during their previously non-overlapping uniform time windows of active MPT control.

Abstract: An apparatus may include a first switch leg connected between a first input terminal and a first output terminal, the first switch leg comprising serially connected switches. The apparatus may also include a second switch leg connected between a second input terminal and the first output terminal, the second switch leg comprising serially connected switches. The apparatus may further include a third switch leg connected between an input voltage midpoint and the first output terminal. A control circuit may control the first switch leg, the second switch leg and the third switch leg.

Abstract: According to one embodiment, disclosed are a DC-DC converter for preventing the unnecessary consumption of a battery in a solar power-linked energy storage system, and a control method thereof. Particularly, a sensing switch is controlled according to a current mode, and thus unnecessary power consumption can be prevented. In addition, a method for operating a circuit breaker, related thereto, is disclosed.

Abstract: A semiconductor module arrangement includes a housing, a first semiconductor substrate arranged inside the housing, a second semiconductor substrate arranged inside the housing, a first plurality of controllable semiconductor elements, and a second plurality of controllable semiconductor elements. During operation of the semiconductor module arrangement, each controllable semiconductor element of the first plurality of controllable semiconductor elements generates switching losses and conduction losses, the switching losses being greater than the conduction losses. Further during operation of the semiconductor module arrangement, each controllable semiconductor element of the second plurality of controllable semiconductor elements generates switching losses and conduction losses, the conduction losses being greater than the switching losses.

Abstract: A DC bus is connected to a PV array, a battery or both, to power a grid connected inverter load on the bus. A system and method is described for controlling current flow on a DC bus regardless of the type of inverter. A converter receives a DC battery voltage. A switching module controls current flow through the converter. A current generator generates a reference current in response to a reference voltage. A comparator connected at the output of the current generator compares the reference current with a battery current and outputs a signal to a controller. The controller generates a reference value. A PWM generator modulates the switch module to control current flow and energy flow between the DC bus and the battery. The current from the DC bus to the inverter is controlled to allow proper grid-connected operation regardless of inverter type.

Abstract: A switching power supply device includes a power conversion circuit that is provided at a multilayer printed board and includes a plurality of switching circuits and a controller controlling the switching circuits, windings configuring an inductor at the multilayer printed board, and a magnetic sheet on one or both of upper and lower faces of the multilayer printed board. First ends of the windings are connected to the switching circuits, and second ends of the windings are connected to a common output. The controller controls the plurality of switching circuits to periodically vary a position and a time at which magnetic flux generated by current flowing to the windings reaches the maximum magnetic flux density. Thus, the switching power supply device is thin, achieves dispersion of heat generation, handles variations in the magnitude of electric power by varying the area of the board, and effectively reduces unwanted radiation.

Abstract: In a half-bridge module for an inverter, semiconductor switches and signal and power connections are arranged on a first surface of a substrate and coated with a casting compound, and external connection contacts for the signal and power connections extend through the casting compound to the exterior. In various embodiments, the external connection contacts extend from the casting compound from four second surfaces that are orthogonal to the first surface, and have a first right angle bend outside the casting compound, such that the ends of the external connection contacts are perpendicular to the first surface. The invention also relates to a corresponding inverter.

Abstract: A power control unit includes a power device, a heat dissipation member disposed to face the power device with an insulating resin member interposed therebetween, and a plurality of plate-shaped bus bars each of which has one end connected to the power device, in which a plurality of input bus bars connected to an input terminal of the power device are provided as the bus bar, and at least one of the plurality of input bus bars is erected so that a direction along a plate width is aligned with a direction along a normal line of a surface of the heat dissipation member facing the power device, and is disposed with respect to the heat dissipation member with the insulating resin member interposed therebetween.

Abstract: A semiconductor device includes: a first circuit including semiconductor switching elements connected in parallel, each semiconductor switching element having a first electrode, a second electrode, and a third electrode and being configured to be controlled, according to a voltage between the first electrode and the third electrode, to attain conduction or non-conduction between the second electrode and the third electrode; and a control unit connected to the first electrode of each semiconductor switching element and configured to control the voltage between the first electrode and the third electrode. The semiconductor device is configured to satisfy a first condition that an impedance Zg on a first path between the first electrodes of the respective semiconductor switching elements is higher, by at least a set value, than an impedance Zs on a third path making connection between the third electrodes of the respective semiconductor switching elements.

Abstract: A high voltage power supply is disclosed. The high voltage power supply comprises a primary winding and one or more secondary windings. In one embodiment, a single secondary winding is used and the high voltage doubler circuit comprises a capacitor string and a diode string. In another embodiment, a plurality of secondary windings are used and the high voltage doubler circuit comprises a plurality of low voltage doubler circuits arranged in series. To create a more uniform distribution of voltage across the capacitors in the high voltage doubler circuit, one or more shields are disposed on the printed circuit board. In certain embodiments, a high voltage shield is disposed at the high voltage output and a low voltage shield is disposed at the low voltage end of the high voltage doubler circuit. One or more intermediate shields may be disposed in the high voltage doubler circuit.

Abstract: A bidirectional energy transfer system includes a supply device having a vehicle port, an inverter port, a converter, and an isolation transformer. The vehicle port is configured to electrically couple the supply device to an electrified vehicle. The inverter port is configured to electrically couple the supply device to an inverter that is separate from the supply device.

Abstract: A negative-side bus bar 41 includes a capacitor connection portion and first and second negative terminal portions 271 exposed from a resin portion 44 and connected to a DC negative-side terminals 103 of first and second power semiconductor modules 30. A partition portion 252b of a case 252 is provided with a protruding portion 281 that protrudes toward a mold bus bar 40 further than an upper surface 257 of the first and second power semiconductor modules 30 and is thermally coupled to the mold bus bar 40. The projecting portion 281 is disposed between a root portion 275 of an exposed portion where the first negative electrode terminal portion 271 is exposed from the resin portion 44 and a second root portion 275 of an exposed portion where the second negative electrode terminal portion 271 is exposed from the resin portion 44.

Abstract: A power factor correction circuit configured to increase the amount of useful power in an AC electrical system. The power factor correction circuit optionally includes one or more capacitors and one or more resistors configured to realign a phase angle between a voltage and current of an AC power source. Examples are offered illustrating the disclosed circuit in use with a single phase or multi-phase AC power source ranging in voltage from 100 volts or less to 500 volts or more.

Abstract: A method for three-phase infeed of electrical power from a DC source into a three-phase AC grid by means of an inverter includes measuring phase-specific grid voltages of the three-phase AC grid, and determining a grid frequency from the measured phase-specific grid voltages. The method also includes generating phase-specific voltage reference values from the phase-specifically measured grid voltages and the determined grid frequency, and generating phase-specific target current values using phase-specific predetermined target current amplitude values, the phase-specific voltage reference values and respective grid voltage amplitudes.

Abstract: An AC electrical system for a vehicle and methods of operating the same are provided. In one aspect, an AC electrical system includes a first electric machine mechanically coupled with a first spool of a gas turbine engine and a second electric machine mechanically coupled with a second spool of the gas turbine engine. The system also includes a first AC bus and a second AC bus. A first electrical channel electrically couples the first electric machine to the first AC bus and a second electrical channel electrically couples the second electric machine to the second AC bus. The system also includes one or more connection links and one or more power converters for selectively electrically coupling the first and second electrical channels so that electrical power generated by one electric machine can be converted and shared with the other electric machine and electrical loads of the other channel.

Abstract: A voltage controller generates an AC current command value by adding a feed-forward term to a result of a control calculation performed for reducing a difference of a detected value of an AC voltage with respect to an AC voltage command value, the feed-forward term being determined by multiplying, by a gain, a detected value of primary winding current of a transformer. A current controller generates an inverter control command value by a control calculation performed for reducing a difference of a detected value of output current of the inverter with respect to the AC current command value. A PWM circuit generates a control signal for the inverter by comparing the inverter control command value with a predetermined carrier wave. When exciting inrush current is detected in a detected value of the primary winding current, the voltage controller sets the gain smaller than the gain when the exciting inrush current is not detected.

Abstract: A dead time control method (100) comprising the steps of: converting the DC link voltage, output current and output voltage to digital values with an ADC (Analog to Digital converter) (102); calculating the hysteresis band for adaptive hysteresis current control using the values read by the ADC and updating the band value via recalculating it at each sampling time (103); calculating the IrefH and IrefL values using the hysteresis band and Iref (103a); generating the PWM signal by hysteresis current control (104), generating two auxiliary control signals as VP, VN (105); in the region where VP=1 and VN=0, applying of the drive signal of T1 without setting dead time wherein T1 is the conduction duration of an upper switch, and not applying the drive signal of T2 wherein T2 is the turn off duration of said upper switch and is the conduction duration of a lower switch (106).

Abstract: A semiconductor device includes a substrate having a first surface, a first electrode, a second electrode and a third electrode formed on the first surface, a first semiconductor element and a second semiconductor element disposed in the interior of the substrate, a first wiring group electrically connecting the first electrode to the first semiconductor element, and a fourth wiring group electrically connecting the second semiconductor element to the second electrode. The first wiring group includes a first connection part disposed in the interior of the substrate. The fourth wiring group includes a second connection part disposed in the interior of the substrate. When a voltage is applied between the first electrode and the third electrode to cause current to flow through the second electrode, a direction of current flowing through first connection part is opposite to a direction of current flowing through the second connection part.

Abstract: A rotation calculation unit calculates a rotation speed of a virtual generator on the basis of a rotor model to simulate driving of the virtual generator and calculates the rotation speed of the virtual generator. A target power determination unit determines target values of active power and reactive power of an inverter on the basis of the calculated rotation speed. A command generation unit generates a control command for the inverter on the basis of the determined target values of the active power and the reactive power.

Abstract: A method of controlling a matrix converter system is provided. The method includes receiving an operating condition and consulting a trained Q-data structure for reward values associated with respective switching states of the switching matrix for an operating state that corresponds to the operating condition. The Q-data structure is trained using Q-learning to map a reward value predicted for respective switching states to respective discrete operating states. The method further includes sorting the reward values predicted for the respective switching states mapped to the operating state that corresponds to the operating condition, selecting a subset of the set of the mappings as a function of a result of sorting the reward values associated with the switching states of the operating state, evaluating each switching state included in the subset, and selecting an optimal switching state for the operating condition based on a result of evaluating the switching states of the subset.

Abstract: The present subject matter refers a discharge circuit for a smoothing capacitor within a power-distribution-unit. The discharge circuit comprises a first sub-circuit connected in parallel to a DC-Link capacitor, said first sub-circuit in turn comprises a series connection of a first switching element (SE) and a first discharge resistor, wherein the DC-link capacitor is connected in parallel to a power supply. A second sub-circuit is connected in parallel to the DC-Link capacitor and comprises a series connection of a second switching element (SE) and a second discharge resistor. A control device is configured to control the plurality of SEs within the sub-circuits by scheduling switching of the plurality of SEs. Such scheduling comprises switching ON of the second SE after a switching ON of the first SE for enabling a discharging of the DC link capacitor within a predetermined duration.

Abstract: A motor control device includes a controller to control a three-phase current by feeding back a control current value obtained based on the three-phase current. The controller is configured or programmed to execute first feedback control of feeding back any one of a first control current value calculated based on a second phase current and the third phase current, a second control current value calculated based on the third phase current and a first phase current, and a third control current value calculated based on the first phase current and the second phase current as a control current value and second feedback control in which the first control current value, the second control current value, and the third control current value are switched and fed back as the control current value.

Abstract: A semiconductor device of embodiments includes an insulating substrate, a first main terminal, a second main terminal, an output terminal, a first metal layer connected to the first main terminal, a second metal layer connected to the second main terminal, a third metal layer disposed between the first metal layer and the second metal layer and connected to the output terminal, a first semiconductor chip and a second semiconductor chip provided on the first metal layer, a third semiconductor chip and a fourth semiconductor chip provided on the third metal layer, and a conductive member on the second metal layer. Then, the second metal layer includes a slit. The conductive member is provided between the end portion of the second metal layer and the slit.

Abstract: Various examples of power converters including Integrated Capacitor Blocked Transistor (ICBT) cells and methods of control of power converters having ICBT cells are described. In one example, a power converter includes an upper arm including a plurality of upper ICBT cells connected in series to form a series connection path and a lower arm including a plurality of lower ICBT cells connected in series in the series connection path. A controller can be configured to provide a control signal pair to each of the upper ICBT cells and a complementary control signal pair to each of the lower ICBT cells to control the converter output. A capacitor voltage controller can be configured to balance a voltage potential among ICBT capacitors in at least one of the upper arm and the lower arm.

Abstract: A photovoltaic inverter, a photovoltaic system, and a method for controlling discharging are provided. The photovoltaic inverter includes a first DCDC converter, an inverter circuit, a first discharging circuit, and a controller. A port capacitor is connected between a positive input end and a negative input end of the first DCDC converter. The port capacitor includes an X capacitor and a first group of Y capacitors. The first discharging circuit is connected between a common terminal of the first group of Y capacitors and a direct current bus, where the common terminal of the first group of Y capacitors is grounded. The controller is configured to control, when receiving a rapid shutdown instruction, the first discharging circuit to operate. The first discharging circuit is configured to discharge electrical energy of the port capacitor.

Abstract: An inverter is provided for driving a motor. A first capacitor, and a second capacitor including capacitors connected in series, are connected in parallel to a DC power supply. A switch circuit having switching elements is connected between the inverter and the second capacitor. A control circuit is provided for controlling the inverter and the switch circuit. The control circuit performs control to switch the switch circuit so as to supply current from the second capacitor to the inverter during 3-level operation, and supply current from both of the first capacitor and the second capacitor to the inverter during 2-level operation.

Abstract: Techniques to send digital information from the secondary side to the primary side of a power converter, such as a flyback power converter, without the need for a separate, isolated communication channel. The power converter of this disclosure may send digital information from secondary side to the primary side through a power transformer while the power converter operates in a mixed mode scenario, e.g. critical conduction mode (CRCM) and discontinuous conduction mode (DCM). In CRCM, a controller circuit for the power converter may encode digital information by modulating the diode conduction time in a switching cycle. In DCM, the controller circuit may encode digital information by modulating the period of time for each switching cycle, e.g. increased period, decreased period or no change to the period.

Abstract: A power supply circuit includes at least two input terminals that receive an input voltage, a transformer including a primary side electrically connected to the input voltage, a rectifier electrically connected to a secondary side of the transformer, and a boost switch electrically connected in parallel with the rectifier and a pair of output voltage terminals that include a first output voltage terminal and a second output voltage terminal. The input voltage is electrically connected to an AC source, and each of the at least two input terminals receives a different phase of the AC source.

Abstract: A method provides current limitation in the event of transient voltage variations at an AC output of a multilevel inverter that includes a bridge circuit with a first DC input, a second DC input, a neutral terminal and a bridge output, as well as a line filter with a choke connected between the bridge output and the AC output, and a capacitor connected between the AC output and the neutral terminal. In the method, depending on the voltage at the capacitor, when a first current threshold is exceeded by the choke current, a regular operating mode is interrupted and measures for current limitation are initiated. A multilevel inverter is further disclosed including a control circuit that is configured to carry out such a method.

Abstract: Methods, apparatus, systems, and articles of manufacture for zero voltage switching of flyback converters are disclosed. An example apparatus includes a first driver to operate a first switch to direct a first current to flow to a first winding of a transformer, and a second driver to operate a second switch to direct a second current to flow to a second winding of the transformer and operate the second switch to cause the second current to discharge a voltage of the first switch.

Abstract: The invention relates to an insulated DC/DC converter comprising: a magnetic component having a primary part and a secondary part separated by an electrical insulation barrier; breakers linked to the primary part of the magnetic component allowing the magnetic component to transfer energy from the primary part to the secondary part and to store energy at the level of the primary part; and in which the secondary part of the magnetic component comprises a first arm and a second arm, each arm comprising a first breaker, a secondary and a second breaker in series; an intermediate point of the secondary of the first arm being connected to an intermediate point of the secondary of the second arm.

Abstract: When providing alternating current (AC) power to operate AC powered devices such as power tools (such as drills, table saws, miter saws), equipment (such as lawn mowers), and consumer products (such as refrigerators, television, lights) without being tied to a fixed utility power supply typically requires a generator (such as an internal combustion engine based generator) or a battery powered inverter. In order to meet power and runtime needs for these devices, a battery powered inverter must be relatively large and expensive. This simple fact prohibits their use in many environments.

Abstract: A power conversion device suppresses voltage variation of a power supply bus. The device includes a variation compensation circuit and a control circuit. The variation compensation circuit includes: a first capacitor connected to the power supply bus; a second capacitor connected in series between the first capacitor and a ground; an auxiliary capacitor; and a converter including a switching element and having a voltage step-down function, the converter being connected to the second capacitor and the auxiliary capacitor. The control circuit includes an active power calculating section that calculates instantaneous active power ip in the variation compensation circuit. The control circuit controls the voltage Vc of the auxiliary capacitor using the instantaneous active power ip.

Abstract: A power conversion device suppresses voltage variation of a power supply bus. The device includes a variation compensation circuit and a control circuit. The variation compensation circuit includes: a first capacitor connected to the power supply bus; a second capacitor connected in series between the first capacitor and a ground; an auxiliary capacitor; and a converter including a switching element and having a voltage step-down function, the converter being connected to the second capacitor and the auxiliary capacitor. The control circuit includes a proportional resonant control section having a peak gain for variation with a frequency ?0 which is twice a frequency of the single-phase alternating current. The control circuit uses the proportional resonant control section to generate a signal for controlling the switching element.