Abstract: A power conversion device includes a main circuit unit (direct-current main circuit) that converts direct-current power into alternating-current power, and a control unit that controls the direct-current main circuit. The direct-current main circuit includes a voltage detector (detector) that detects a capacitor voltage and a discharge circuit that discharges energy accumulated in a capacitor. The control unit includes a detection circuit that estimates a capacitor voltage during a normal operation based on a voltage transmitted from the voltage detector in a state where the main circuit unit is disconnected from a power supply and that detects a sign that a short circuit fault occurs in the capacitor, and a control circuit that outputs a control signal for controlling the discharge circuit to operate when the control circuit receives a detection signal from the detection circuit.

Abstract: A low-side driver circuit includes a low-side driver integrated circuit and a controllable switch. The low-side driver integrated circuit is responsive to an on-off command input signal to selectively operate in an ON mode and an OFF mode. The controllable switch is responsive to the on-off command signal to selectively operate in a CLOSED mode and an OPEN mode. The low-side driver integrated circuit and the controllable switch are configured to simultaneously operate in the ON mode and the CLOSED mode, respectively, and in the OFF mode and the OPEN mode, respectively. During a voltage transient the potential will be realized across the controllable switch, thus protecting the lower voltage rated low-side integrated circuit.

Abstract: An inverter may include an inversion unit for converting a direct current bus voltage into an alternating current voltage, a first snubber unit, and a second snubber unit. The inversion unit may include a first external switch, a first internal switch, a second internal switch, and a second external switch which are connected in series in order between a direct current bus positive voltage terminal and a direct current bus negative voltage terminal. The first snubber unit may be connected between the direct current bus negative voltage terminal and the first internal switch for suppressing voltage stress of the first internal switch. The second snubber unit may be connected between the direct current bus positive voltage terminal and the second internal switch for suppressing voltage stress of the second internal switch.

Abstract: A solar module has a solar cell which generates a DC voltage. The module has a converter for converting a DC voltage fed into its input. The module contains a semiconductor switch and a controller which drives a switching input of the semiconductor switch. The controller drives the semiconductor switch variably so that the semiconductor switch switches more slowly during the transition operation than during normal operation, thereby reducing a dynamic overvoltage on the switch such that the voltage present on the switch does not exceed the blocking voltage of the switch.

Abstract: A power converter in one aspect limits the magnetic flux in a transformer. A control circuit included in the power converter includes a pulse width modulator, a logic circuit and a saturation prevention circuit. The saturation prevention circuit asserts a first signal when a first integral value of the input voltage reaches a first threshold value and asserts a second signal after a delay time that begins when a difference between the first integral value and a second integral value of a reset voltage of the transformer falls to a second threshold value. The logic circuit turns off the switch when the first signal is asserted, and allows the switch to turn on and off in accordance with the pulse width modulator when the second signal is asserted.

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: An electric power transmission system includes at each end of a high voltage direct current transmission line including three conductors, a converter station for conversion of an alternating voltage into a direct voltage for transmitting direct current between the stations in all three conductors. Each station has a voltage source converter and an extra phase leg connected between the two pole conductors of the direct voltage side of the converter. A third of the conductors is connected to a midpoint between current valves of the extra phase leg. An arrangement is adapted to control the current valves of the extra phase leg to switch for connecting the third conductor either to the first pole conductor or the second pole conductor for utilizing the third conductor for conducting current between the stations.

Abstract: A voltage reduction detection circuit for a switching power supply includes a first rectifier diode having an anode connected to the output terminal of a secondary winding; a second rectifier diode connected in parallel with the first rectifier diode and having a cathode connected to the output terminal; and resistors arranged to divide the voltage between the cathode side of the first rectifier diode and the anode side of the second rectifier diode. The circuit detects a voltage reduction in an AC power supply (feeding AC power to the switching power supply) based on variation in a voltage resulting from voltage division by the resistors.

Abstract: There is provided a control system and method related to the use of insulated gate bipolar transistor (IGBT) devices in vehicles. An exemplary control method includes applying a voltage to a gate of an IGBT device to turn the IGBT on, measuring the collector-to-emitter voltage of the IGBT, and comparing the measured collector-to-emitter voltage to a voltage reference. The exemplary method also includes generating a fault condition if the measured collector-to-emitter voltage exceeds the voltage reference. The exemplary method additionally includes initiating a soft turn-off in response to the fault condition by reducing the voltage applied to the gate of the IGBT to a voltage slightly greater than a rated threshold voltage of the IGBT.

Abstract: A control circuit, a control method, and a power supply device are provided. The control circuit includes an obtaining sub-circuit, adapted to obtain a voltage signal from a reverse surge current when the reverse surge current appears on a primary side of a switch power circuit of a synchronous rectification circuit; a maintaining sub-circuit, adapted to continuously output a first control signal in a preset first time period when the voltage signal is greater than a preset first voltage threshold; and a control sub-circuit, adapted to control and switch off switch tubes of the secondary side of the switch power circuit of the synchronous rectification circuit according to the first control signal. Thus, a reverse current surge of the switch power circuit of the synchronous rectification circuit can be effectively suppressed, and the safety of a switch power supply of the synchronous rectification circuit can be effectively protected.

Abstract: The present invention discloses a flux linkage compensator, which applies to an UPS system and comprises a load transformer flux linkage observer, a compensation voltage command generator, and a flux linkage command generator. The load transformer flux linkage observer generates a load transformer flux linkage signal. The flux linkage command generator generates a flux linkage command signal. The difference between the load transformer flux linkage signal and the flux linkage command signal forms a flux linkage deviation signal. The compensation voltage command generator generates a voltage compensation signal to make the flux linkage deviation signal approach zero. Thereby, the flux linkage compensator can compensate for the flux linkage deviation occurring in starting the UPS system. Thus, the present invention can perform voltage compensation fast and reliably and inhibit the inrush current effectively.

Abstract: A method of operating a neutral point clamped (NPC) three level converter is provided. The NPC converter includes at least two legs, each leg comprising first and second top switches connected in series at a first mid point. The converter further includes first and second bottom switches connected in series at a second mid point, and first and second middle switches connected in series at a third mid point therebetween. The first top and second bottom switches are connected in series at a DC link and the first and the second middle switches are connected between the first and the second mid points. Each of the top, bottom and middle switches has an antiparallel diode thereacross. The method includes alternately switching the first and second top switches to ON state when the first middle switch is in ON state and the second middle switch is in OFF state.

Abstract: A commanded negative-sequence current is added to a commanded current so as to suppress double-frequency pulsation on the DC side. The commanded negative-sequence current is found from three values (i.e., the detected value of positive-sequence voltage vector on the power-supply side, the detected value of negative-sequence voltage vector, and a commanded positive-sequence current). Thus, the pulsations which occur on the DC side of a semiconductor power converter and which have a frequency double the power-supply frequency are suppressed even when the AC power supply is at fault while assuring stability of the current control system, thus permitting stable and continuous operation.

Abstract: An example power supply includes an energy transfer element, a switch, and a controller. The controller includes a modulator, a drive signal generator, a comparator, and a variable current limit generator. The modulator generates an enable signal having logic states responsive to a feedback signal. The drive signal generator either enables or skips enabling a switch of the power supply during a switching period in response to the logic state of the enable signal. The comparator asserts an over current signal to disable the switch if the switch current exceeds a variable current limit. The variable current limit generator sets the variable current limit to a first current limit in response to one logic state of the enable signal and sets the variable current limit to a second current limit if the enable signal transitions logic states and the over current signal is asserted during the switching period.

Abstract: Reverse recovery avoidance when converting power is provided. A first switch and second switch may be operated to supply an AC load with positive current, respective to the AC load, from a DC power source. A third and fourth switch may be operated to supply the AC load with negative current, respective to the AC load, from the DC power source. Four diodes may be employed with the switches. One diode may conduct the positive current when the first switch is off and the second switch is on. Another diode may conduct the negative current when the third switch is off and the fourth switch is on.

Abstract: An example apparatus to regulate an output voltage of a power converter at light/no load conditions includes a driver circuit, a feedback circuit, and an adjustable voltage reference circuit. The driver circuit is coupled to output a drive signal to switch a power switch between an ON state and an OFF state to regulate an output of the power converter. The feedback circuit is coupled to the driver circuit and is further coupled to output an enable signal to switch the power switch to an ON state in response to an output voltage signal. The adjustable voltage reference circuit is coupled to adjust a voltage reference such that a bias winding voltage of the power converter is adjusted nonlinearly in response to a load that is to be coupled to the output of the power converter.

Abstract: A synchronous rectifier circuit of a switching power converter is provided and includes first and second power transistors and first and second diodes connected to a transformer and an output of the power converter for rectifying. An arbiter circuit generates a lock signal to prevent the second power transistor from being turned on when the first power transistor is turned on. A controller generates a drive signal to control the first power transistor according to an on signal and an off signal. A phase-lock circuit generates the off signal according to the on signal. The on signal is enabled once the first diode is forward biased. The one signal enables the drive signal for turning on the first power transistor. The off signal disables the drive signal for turning off the first power transistor. The off signal is enabled before the disabling of the on signal.

Abstract: An inverter device of the present invention includes: an inverter circuit portion that has a plurality of switching elements and that converts direct-current power into alternating-current power; and a temperature detection sensor that detects the temperature of the switching elements, in which, in the inverter circuit portion, a plurality of the switching elements on each of an upper side arm and a lower side arm corresponding to each phase are connected in parallel, and the temperature detection sensor is arranged in an intermediate position between the switching elements connected in parallel.

Abstract: A power converter in one aspect limits the magnetic flux in a transformer. A control circuit included in the power converter includes a pulse width modulator, logic circuits and saturation prevention circuits. The saturation prevention circuits assert a first signal when a first integral value of the input voltage reaches a first threshold value and assert a second signal after a delay time that begins when a difference between the first integral value and a second integral value of a reset voltage of the transformer falls to a second threshold value. The logic circuits turn off the switch when the first signal is asserted, and allow the switch to turn on and off in accordance with the pulse width modulator when the second signal is asserted.

Abstract: A radiation tolerant electrical component is provided without a radiation hardened material FET. A p-channel MOSFET provides switching capabilities in radiated environments because its gate voltage starts at a negative value and becomes more negative with exposure to radiation. Therefore, the gate is still controllable when exposed to radiation.

Abstract: The present invention relates to a transformerless photovoltaic grid-connecting inverting device and an inverting control method thereof. The inverting device comprising a boosting unit, an inverting unit, a grid-connecting unit and a control unit. The boosting unit is connected to a solar cell, for boosting an output voltage of the solar cell and then outputting a direct voltage. The inverting unit is used to convert the direct voltage output by the boosting unit into an alternating voltage. The grid-connecting unit is connected between the inverting unit and an alternating power grid, and closes or breaks up the electrical connection between the inverting unit and the alternating power grid based on a control signal.

Abstract: A power converter includes a reverse-recovery avoidance scheme. The power converter may include deliver current from a direct current (DC) power source to an alternating current (AC) load. A first switch and second switch of the power converter may be operated to supply the AC load with positive current respective to the AC load from the DC power source. A third and fourth switch of the power converter may be operated to supply the AC load with negative current respective to the AC load from the DC power source. A first diode may be electrically coupled in series with the second switch and second diode may be electrically coupled in parallel with the first diode and the second switch. The second diode may conduct the positive current when the first switch is off and the second switch is on. A third diode may be electrically coupled in series with the fourth switch and a fourth diode may be electrically coupled in parallel with the third diode and the fourth switch.

Abstract: Methods and apparatus are provided for operation of a voltage source inverter. A method of operating a voltage source inverter having an output with multiple voltage phases having a DC voltage level, the method comprising sensing a low output frequency condition; determining a DC voltage offset responsive to the low output frequency condition; and applying the DC voltage offset when operating the voltage source inverter resulting in a change to the DC voltage level of the multiple voltage phases.

Abstract: A 3-level power converter is provided, which is reduced in size of the converter, reduced in floating inductance of each of wirings interconnecting between respective elements, and easily attached with a snubber circuit. The 3-level power converter performs on/off control of first to fourth switching elements 1 to 4 so as to output a 3-level voltage from an AC output terminal AC, wherein the power converter has a first module 11 including the first and fourth switching elements 1 and 4 as a configuration unit, a second module 12 including the second and third switching elements 2 and 3 as a configuration unit, a third module 14 including a first coupling diode 5 as a configuration unit, and a fourth module 13 including a second coupling diode as a configuration unit, and the second module 11, the fourth module 14, the third module 13, and the first module 11 are sequentially arranged in a line from a position near the AC output terminal AC.

Abstract: System and method for protecting a power converter. The system includes a first comparator configured to receive a first threshold signal and a first signal and to generate a first comparison signal. The first signal is associated with an input current for a power converter. Additionally, the system includes a second comparator configured to receive a second threshold signal and the first signal and to generate a second comparison signal. The second threshold signal is different from the first threshold signal in magnitude. Moreover, the system includes a first detection component configured to receive at least the second comparison signal, detect the second comparison signal only if one or more predetermined conditions are satisfied, and generate a first detection signal based on at least information associated with the detected second comparison signal.

Abstract: In a rotary electric system, a switch member includes at least one of a first switch and a second switch. The first switch is connected between a neutral point of multiphase stator windings and a high-side electrode of a direct current power source. The second switch is connected between the neutral point and a low-side electrode of the direct current power source. A controller works to turn the switch member off and on thereby switching control of the multiphase inverter between full-wave driving mode and half-wave driving mode. The full-wave driving mode allows the controller to drive all of the high-side and low-side switching elements per phase of the multiphase stator windings. The half-wave driving mode allows the controller to drive any one of the high-side switching element and the low-side switching element per phase of the multiphase stator windings.

Abstract: An energy transmission device includes: a semiconductor device formed on a first semiconductor substrate; a semiconductor integrated circuit including a reverse current preventing diode and a control circuit; a DC voltage source; and a transformer. The reverse current preventing diode includes a reverse current preventing layer of a second conductivity type formed at a surface of a second semiconductor substrate, and a well layer of a first conductivity type formed in the second semiconductor substrate and covering the reverse current preventing layer. The transformer includes a primary winding connected in series with the semiconductor device and the DC voltage source, and a first secondary winding connected to a load. The energy transmission device is configured so that electric power is supplied from the first secondary winding of the transformer to the load. A second drain electrode of the semiconductor device is electrically connected to the reverse current preventing layer.

Abstract: The present invention can include an image forming apparatus having an electrical load, a supplying circuit configured to supply an electrical power to the electrical load, and an output circuit configured to output a voltage according to a current value of the electrical power being supplied to the electrical load. The present invention may also provide for a controller configured to control an electrical current flowing in the electrical load based on an output voltage value of the output circuit as a feedback value, and an inhibiting circuit configured to inhibit a reverse current to flow in the output circuit when the supplying circuit is turned off.

Abstract: A boost device boosts an input voltage to an output voltage across an output capacitor, and includes an output diode coupled to the output capacitor, and a transformer coupled to a first switch, a clamp circuit and a boost circuit. The clamp circuit is coupled across a first winding of the transformer, and includes a clamp capacitor coupled in series to a second switch. The output capacitor is capable of being charged through the output diode with an induced voltage across a second winding of the transformer. The boost circuit is capable of being charged with the induced voltage across the second winding, and of charging the output capacitor so as to boost the output voltage across the output capacitor.

Abstract: An energy effective switching power supply apparatus and an energy effective method thereof. The energy effective switching power supply apparatus includes a power transforming part having first and second coils to induce a voltage to the second coil using interactions between the first and the second coils with respect to the input voltage, a power outputting part to output a sensing signal when it is determined that a first DC voltage output by rectifying and smoothing the voltage induced to the second coil is greater than or equal to a reference voltage level, and a switching controlling part to adjust a switching frequency of a switching device to interrupt a current flowing in the first coil of the power transforming part when the sensing signal is received. Accordingly, a switching loss is controlled and an energy loss is reduced.

Abstract: A power converter is provided with a rectifying circuit, an inverter circuit, and a common mode filter including a common mode choke coil and a capacitor. The switching frequency of a PWM rectifying circuit is set at three times the switching frequency of a PWM inverter. Alternatively, the resonance frequency of the common mode filter is set at twice the carrier frequency of the rectifying circuit or the PWM inverter circuit or more.

Abstract: Embodiments of systems and methods for powering a load are provided. In one embodiment, a method may include providing a power converter comprising electrical circuitry comprising at least a first leg and a second leg, supplying an input power signal to the power converter, supplying at least a first gating control signal to the first leg, supplying at least a second gating control signal to the second leg, and outputting at least one output power signal to the load responsive at least in part to the first and the second gating control signals supplied. According to this example embodiment, the first gating signal and the second gating signal may each comprise a waveform comprising a notch, and the second gating control signal may be phase shifted relative to the first gating control signal.

Abstract: A circuit apparatus for providing an AC voltage to a load. The apparatus may include: a first, second, third and fourth switch, wherein the first switch is connected between a first node and a first terminal of the second switch and the fourth switch is connected between a second node and a first terminal of the fourth switch; a voltage source, wherein the voltage source is electrically connected between the first node and the second node; a resistive divider connected across the voltage source; a first resistor connected across the first switch a second resistor connected across the third switch; first connecting means for configurably connecting a second terminal of the second switch to the second node; second connecting means for configurably connecting a second terminal of the third switch to the first node; and third connecting means for configurably connecting the second terminal of the second switch in series with the second terminal of the third switch.

Abstract: The present invention discloses a minimum on-time reduction method for a switching power conversion, comprising the steps of: generating a first reset signal and an over-supply pulse signal according to a current sensing signal and a reference signal; generating a blanking signal according to a count number of the over-supply pulse signal; and generating a second reset signal by performing Logic-AND operation on the first reset signal and the blanking signal. Furthermore, the present invention also provides a minimum on-time reduction apparatus for a power conversion, and a system using the minimum on-time reduction apparatus for a power conversion.

Abstract: It is an object to provide a DC/DC converter that can stabilize power supply potential in use. It is another object to provide a semiconductor device in which circuit operation is stabilized. In addition to a power supply that supplies potential to be reference potential of boosting in a DC/DC converter, a power supply for charging a capacitor in the DC/DC converter is provided. Accordingly, loads to the power supply that supplies the reference potential of boosting can be reduced. Further, as power for charging the capacitor in the DC/DC converter, power supplied from not an antenna but a secondary battery is used. More specifically, a secondary battery is used as a power supply that supplies power to a buffer circuit or an inverter circuit. Thus, power supplied from the antenna can be stabilized. In other words, operation of a logic circuit and an analog circuit can be stabilized.

Abstract: Methods and apparatus to provide low harmonic distortion AC power for distribution by converting energy from natural or renewable sources into electrical form, and constructing a current waveform on a primary winding of a transformer by recapturing inductive energy previously stored in the transformer so as to transform the converted electrical energy into substantially sinusoidal AC voltage at a secondary winding of the transformer. For example, AC power may be supplied to a utility power grid from raw electrical energy from renewable energy sources (e.g., solar cells). An inverter may construct the primary winding current waveform using two unidirectional switches. On each half cycle, one of the switches first applies energy previously recaptured from primary winding inductance, and then applies the raw energy to the transformer primary winding at the utility power grid frequency. Accordingly, the constructed primary winding current may exhibit substantially improved total harmonic distortion.

Abstract: The motor driving inverter circuit module includes first-phase, second-phase, and third-phase high voltage drivers generating first-phase, second-phase, and third-phase upper arm and lower arm driving signals in response to input signals for driving the first-phase, second-phase, and third-phase upper and lower arms and a first-phase, second-phase, and third-phase upper arm and lower arm transistors, generating first-phase, second-phase, and third-phase motor driving output signals in response to the first-phase, second-phase, and third-phase upper arm and lower arm driving signals of the first-phase, second-phase, and third-phase high voltage drivers. The first-phase, second-phase, and third-phase high voltage drivers and the first-phase, second-phase, and third-phase upper arm and lower arm transistors are respectively integrated into separate chips.

Abstract: A control circuit for use in a power converter in one aspect limits the magnetic flux in a transformer. Controlled current sources produce a first current that is proportional to an input voltage of the power converter and a second current that is proportional to a reset voltage of the transformer. An integrating capacitor is charged with the first current and discharged with the second current, where a voltage on the capacitor is representative of the magnetic flux in the transformer. A logic circuit is adapted to turn off the switch when the voltage on the integrating capacitor is greater than or equal to a first threshold voltage, and to allow the switch to turn on and off in accordance with a pulse width modulation signal after a delay time that begins when the integrating capacitor discharges to a second threshold voltage.

Abstract: An integrated control circuit for controlling a switching power supply, a switching power supply incorporating the same, and a method of controlling the switching power supply, where the control IC includes a current comparator that detects current flowing through a switching device, a flip-flop circuit that controls the ON-period of the switching device, an averaging circuit that converts the peak load current value to a time-average, a comparator that detects an overloaded state from the load current, a delay circuit that sets a time from detecting the overcurrent state to stopping the switching operation, a latch circuit that stops the switching operation for a period of time, a first reference voltage supply used in the current comparator, which has a higher voltage value than a second reference voltage supply used in the comparator.

Abstract: A method and apparatus for recovering leakage energy during DC power to AC power conversion. The apparatus comprises a leakage energy recovery circuit for storing leakage energy from a transformer and selectively coupling stored leakage energy to an input of the transformer.

Abstract: An exemplary power supply circuit (200) includes a pulse width modulation circuit (220) providing a pulse signal, a voltage conversion circuit (210) converting a primary voltage to an output voltage according to the pulse signal, a feedback circuit (260), and a control circuit (290). The feedback circuit includes a sampling branch (261) detecting a current of the voltage conversion circuit and accordingly providing a feedback signal, and a voltage division branch (262) electrically coupled to the sampling branch. The control circuit is electrically coupled to the voltage division branch, and is configured for disabling the voltage division branch after a predetermined period of time when the output voltage is within a predetermined range.

Abstract: A voltage detector circuitry extracts a signal on primary side of a transformer in a flyback converter, which is proportional to the output voltage of the converter without voltage drop on the rectifier diode and leakage inductance effect on the transformer, and good output regulation is achieved without opto-coupler. To accurately detect the output voltage on the primary side, the knee point of the voltage on an auxiliary winding of the transformer is detected. A current limit proportional to the input voltage of the converter is produced from the voltage on an auxiliary winding for stabilizing the output current in constant current mode.

Abstract: A control circuit for use in a power converter in one aspect limits the magnetic flux in a transformer of a switching power converter. A first controlled current source has a first current that is substantially directly proportional to an input voltage to be applied to a winding of the transformer. A second controlled current source has a second current that is substantially directly proportional to a reset voltage to be applied to the winding of the transformer. A first switch is adapted to charge an integrating capacitor with the first current while the input voltage is applied to the winding of the transformer. A second switch is adapted to discharge the integrating capacitor with the second current when the reset voltage is applied to the winding of the transformer. A third switch is adapted to remove and to prevent application of the input voltage to the winding of the transformer.

Abstract: A system interconnection inverter includes a step-up converter and an inverter. Moreover, the system interconnection inverter includes a short-circuit current-interrupting diode with a cathode connected to an input terminal of a negative bus, a semiconductor switch connected to an anode of the short-circuit current-interrupting diode, a semiconductor switch drive circuit that drives the semiconductor switch, a semiconductor switch-off circuit that turns off the semiconductor switch drive circuit when negative power is applied such that electric current flows from a cathode toward an anode of the input terminal, and a control circuit that controls the semiconductor switch drive circuit.

Abstract: A power converter and a PWM controller for compensating a maximum output power includes a power switch, an oscillator, a control circuit and a delay modulator. The oscillator generates a pulse signal. The control circuit is coupled to the oscillator for generating a PWM signal and an over current signal in response to the pulse signal and a current sense signal of the power converter. The delay modulator is coupled to the control circuit for generating a delay control signal in response to the PWM signal and the over current signal, wherein the delay control signal is used to prolong a propagation delay time of the control circuit in response to the on-time of the PWM signal, and the propagation delay time can be compensated by the on-time of the PWM signal to limit the maximum output power under a high-line input voltage and a heavy-load condition.

Abstract: Mitigating the DC content of an AC output from an inverter is important for electrical system reliability. The inverter may be powered by unbalanced DC inputs while still mitigating the DC content of the AC output wavefrom. The present invention provides methods to mitigate the DC content in the output DC voltage by reshaping the PWM reference signals (carrier signals) according to the DC content in such a way that the DC content is canceled. These reshaped PWM reference signals may be, for example, unsymmetrical reference waveforms. Unlike conventional methods for providing an AC voltage from a DC voltage with an inverter, which may result in DC content in the output AC voltage when an unbalanced DC input voltage is supplied, the present invention provides methods for mitigating the DC content in an AC voltage, even if the inverter providing the AC voltage is supplied with unbalanced DC voltage.

Abstract: In a switching power supply apparatus, an inductor, a transformer, a first switching circuit, a second switching circuit, and a capacitor are connected to each other so that a first switching element and a second switching element can be alternately turned on and off, an output can be obtained from a secondary winding of the transformer, and an output voltage can be controlled by controlling the ON period of the first switching element. The secondary winding of the transformer is connected to a first rectifying and smoothing circuit. A first control circuit is configured to operate using a DC voltage supplied from a second rectifying and smoothing circuit. After the second switching element has been turned on, the second switching element is forcefully turned off at a predetermined time set by a turn-off circuit included in a second control circuit that operates using an AC voltage.

Abstract: In a power switching circuit, a second commutation member has a second commutation path electrically connected in parallel to a first commutation path and a second diode provided in the second commutation path and electrically connected antiparallel to a semiconductor switching element. While the semiconductor switching element is off, the second commutation path allows a second current based on the inductive load to flow therethrough in a forward direction of the second diode within a commutation period. The second diode has a second reverse recovery time shorter than a first reverse recovery time of the first diode. A second inductance of the second commutation path is higher than a first inductance of the first commutation path.

Abstract: The present invention discloses a method and a circuit for controlling a start-up cycle of an integrated circuit in a circuit system. The method and circuit determine whether or not an input power of the circuit system and a bias voltage power of the integrated circuit have reached a normal operating voltage range to control the bias voltage power to produce a start-up cycle of the integrated circuit. The method and circuit also provides a protection mechanism for an overload of the circuit system overload, so that the integrated circuit can moderate surges and prevent damages.

Abstract: Switching device for linking various electrical voltage levels in a motor vehicle, in which a drive voltage level has an electric drive machine which may be actuated by a power converter, and a drive energy accumulator which is associated with an intermediate circuit, and in which the drive voltage level is connected to a vehicle electrical system voltage level by an electrical converter. The electrical converter is designed as a coupling circuit which is connected at the drive side to at least one node point of a winding circuit of the electric drive machine and to a voltage potential relative to the intermediate circuit. The coupling circuit is connected at the vehicle electrical system side to the vehicle electrical system via a switching unit which has at least one non-diminishing, finite impedance.