2618results about How to "Reduce switching losses" patented technology

A bidirectional active power conditioner includes a DC side, a bidirectional DC / DC power converter, a DC / AC inverter and an AC side. The DC side electrically connects with a DC source while the AC side electrically connects with a load and an AC source. The bidirectional DC / DC power converter is controlled via high-frequency pulse width modulation (PWM) switching so as to generate a predetermined DC voltage or DC current while the DC / AC inverter is controlled to convert the predetermined DC voltage or DC current into a predetermined AC voltage or AC current.

An inverter circuit allowing a single drive circuit to perform both tracking control for tracking resonance frequency fluctuations caused by load fluctuations, and power control, thereby reducing switching loss. An inverter drive circuit part obtains a phase difference between output current and output voltage directed to a load circuit connected to a midpoint of two arm circuits of the inverter circuit, and controls a phase of the driving signal directed to each semiconductor switch such that the phase difference becomes zero or a predetermined value, enabling an operating frequency of the inverter circuit part to track a resonance frequency of the load circuit, and enabling a current phase to be delayed with respect to a voltage phase, thereby achieving ZCS. Since the phase difference is used, an auxiliary circuit is not necessary for measuring a current value in proximity to the semiconductor switches.

A dual-mode pulse frequency modulation boost converter operates in a hysteretic mode during light load currents to regulate an output voltage using a substantially fixed peak switching current and operates in a continuous mode during heavy load currents to regulate the output voltage using a variable peak switching current. The boost converter senses load power to automatically switch between the hysteretic mode and the continuous mode.

A circuit arrangement and control thereof for igniting a high intensity discharge (HID) lamp, for reducing the high frequency ripple superimposed on the low frequency rectangular waveform lamp current after ignition, and for increased circuit efficiency. The high frequency ignition voltage is only applied to the lamp during ignition phase and is mainly generated by the second stage of the low pass (LP) filter. The first stage of the LP filter whose resonant frequency is below the second stage further attenuates the high frequency ripple current through the lamp in normal operation. The resulting lamp current is a low frequency rectangular wave with less than 10% high frequency ripple. Acoustic resonance is avoided. The inductor in the first stage of LP filter is operated in discontinuous current mode. Doing so, the active switches are in zero current switching (ZCS) to maximize the circuit efficiency.

The present invention relates to a switch mode power supply and a driving method for reducing switching loss and audible noise in the burst mode. The switch mode power supply includes a main switch, a power supply, an output unit, and a switch controller. The power supply includes a transformer having a primary coil connected to the main switch, and supplies power to a secondary coil of the transformer according to the operation of the main switch. The output unit is connected to the secondary coil of the transformer and outputs power supplied to the secondary coil of the transformer. The switch controller receives a feedback signal corresponding to the output voltage of the output unit, a sense signal corresponding to the current flowing to the main switch, and a sync signal corresponding to the voltage difference at the main switch, controls the on / off of the main switch, and determines whether to start the burst mode by using the feedback signal, and maintains the switching operation forcibly off period in the burst mode so that the reference frequency of burst switching may be less than a predetermined value.

The invention discloses a switch voltage-stabilizing circuit which can regulate switching frequency as well as current peak, has high efficiency and has no audio-frequency noise generated in a state of light load, and method thereof. The switch voltage-stabilizing circuit comprises an energy storage component capable of storing energy; a switch electrically coupled to the energy storage component, wherein the energy storage component can store energy when the switch is on, and the energy stored in the energy storage component is transmitted to a load when the switch is off; a control circuit electrically coupled to the switch, wherein the control circuit compares current flowing through the switch with a current threshold, when the current flowing through the switch is more than the current threshold, the switch is off, and the control circuit determines on and off time of the switch according to the load of the switch voltage-stabilizing circuit, when the load becomes big, the on and off time of the switch is reduced, and when the load becomes small, the on and off time of the switch is increased. The current threshold is constant when the circuit has no light load and becomes low with the load reduced when the circuit has light load.

A switching power source comprises a current comparator 27 for comparing a voltage level of signals acquired by a current detector 9 with a reference voltage level VDT to produce detection signals VCP of first or second level L or H; an edge detector 28a for sensing an edge of drive signal VG supplied to a gate terminal of MOS-FET 3 during the period of transition from turning on to off of MOS-FET 3; and a decision means 28b for receiving a current detection signal VCP from current comparator 27 to produce an output signal VLD when edge detector 28a catches an edge of drive signal VG; wherein decision means 28b produces different output signals VLD of respectively first and second voltage levels L and H under the light and heavy load conditions to precisely and certainly detect on the primary side of transformer 2 the load condition on the secondary side of transformer 2 for improvement in conversion efficiency.

The invention discloses a grid-connected photovoltaic inverter and relates to equipment which employs irreversible DC power input conversion as AC power output for a semiconductor device with a control electrode and is used for being used together with a power supply system of a power supply. The equipment consists of a photovoltaic array module, four identical switching tubes, two identical diodes, four identical capacitors, an inductor and a power grid; and the topology ensures not to generate DC component or common mode current for the power grid. Meanwhile, the inverter has low output current ripple and higher efficiency, and overcomes the defects that the conventional full-bridge inverters and other types of transformerless photovoltaic inverters generate DC component in the power grid and generate common mode current or / and higher current ripple. Compared with a half-bridge inverter, the grid-connected photovoltaic inverter reduces the differential mode voltage and current ripple by half.

A burst mode resonant power converter with high conversion efficiency has a rectifier, a power factor correction circuit, a resonant circuit, a controller, and a burst mode triggering unit. The maximum frequency switching end of the controller is connected to a maximum frequency variable circuit. When the load is medium or heavy, the maximum frequency variable circuit increases the maximum switch frequency of the controller. When the load is in the no-load or the light conditions, it reduces the maximum switch frequency thereof. Therefore, the controller reduces the number of times that the resonant circuit switches the bridge switch circuit. The conduction cycle of the 50% pulse signal output to the bridge switch circuit becomes longer. Larger energy can be transmitted at a time to the secondary coil of the transformer. This increases the overall efficiency.

A dual-mode pulse frequency modulation boost converter operates in a hysteretic mode during light load currents to regulate an output voltage using a substantially fixed peak switching current and operates in a continuous mode during heavy load currents to regulate the output voltage using a variable peak switching current. The boost converter senses load power to automatically switch between the hysteretic mode and the continuous mode.

A DC-DC converter has converter circuit portions 11 and 12, transformers Tr.sub.1 and T r.sub.2, and rectifier circuit portions 21 and 22. Two sets of converter circuit portions 11 and 12 respectively include two pairs of switching elements Q.sub.1 to Q.sub.4, and two pairs of switching elements Q.sub.5 to Q.sub.8 connected in full bridge configuration, series capacitors C.sub.1 and C.sub.2 are inserted and connected between the converter circuit portions 11 and 12 and the transformers Tr.sub.1 and Tr.sub.2 respectively. The switching phase of one switching element Q.sub.4 or Q.sub.8 is shifted by a 1 / 3n period from the switching phase of the other switching element Q.sub.1 or Q.sub.5 in the pair of switching elements. The switching phases of corresponding switching elements Q.sub.1 and Q.sub.5 in the converter circuit portions 11 and 12 are shifted by a 1 / 2n period from each other.

A circuitry comprises a converter means for generating an alternating current signal from an energy from an energy source, a piezo transformer with an input and an output, wherein the input of the piezo transformer is electrically coupled to the converter means, to receive the alternating current signal as an excitation on the input side from the converter means, and wherein the output of the piezo transformer is designed to provide an output current, and a load, which is coupled to the output of the piezo transformer, so that output current flows through the same. The load is designed to convert at least part of the electrical energy supplied by the output current flowing through the load into another form of energy. The load is further designed such that a useful power provided in the form of useful energy is substantially proportional to the output current. The circuitry is designed to adjust the output current to a predetermined value. The described circuitry allows the supply of a load with particularly high efficiency, low interference emission and good regulation characteristics.

The invention relates to a drive circuit applied to a power switch tube MOSFET, in particular to a drive circuit of a silicon carbide MOSFET, and belongs to the technical field of drive circuits. The drive circuit aims to solve the problem that when an MOSFET in an existing drive circuit is turned off, the reliability is poor. The drive circuit comprises a PWM control circuit, a drive pulse amplifying circuit, a drive resistor Rg, a first diode D1, a resistor R1, a PNP triode Qoff, a second diode D2 and a capacitor C. According to the drive circuit, the PNP triode Qoff, the resistor R1 and the capacitor C form an MOSFET turn-off circuit; when the MOSFET is turned off quickly, a gate pole positive voltage spike caused by Miller currents is effectively suppressed; meanwhile, a gate pole negative voltage spike can also be suppressed through the second diode D2 and the capacitor C, it is guaranteed that the MOSFET is turned off safely and reliably, and the performance advantages of the silicon carbide MOSFET can be given to full play.

An electrical circuit for providing electrical power for use in powering electronic devices, such as monitors, televisions, white goods, data centers, and telecom circuit boards, is described herein. The electrical circuit includes a voltage reduction circuit cell that includes a first capacitor, a second capacitor, a switching circuit, and a hold capacitor. The switching circuit includes a plurality of switching devices that are coupled to the first and the second capacitors for delivering power from an input terminal to an output terminal. The plurality of switching devices includes at least two switching devices that are coupled to ground. The voltage reduction circuit cell also includes a controller for operating the switching circuit in a plurality of operational modes to deliver an output power signal at a desired voltage level.

This present invention provides a bridge battery voltage equalizer to equalize the voltages of the serially connected battery strings, comprising at least one battery crossing over an energy-transferring circuit. A plurality of the energy-transferring circuits are interconnected in a bridge architecture. Each energy-transferring circuit having four nodes comprises a first semiconductor switch, a first diode, a second semiconductor switch, a second diode, and an inductor. One end of the first element switch is connected to a negative pole of the first diode thereto. A positive pole of the second diode is connected to one end of the second element switch thereto. The inductor is an energy storing element that crosses over between the negative pole of the first diode and the positive pole of the second diode.

Methods, system and apparatus are provided for low speed sensorless rotor angular position estimation that implements reduced switching loss PWM waveforms.

The invention relates to a bidirectionally isolating type series resonance DC / DC converter (100) which comprises voltage-stabilizing capacitors (22, 32), high-frequency converters (20, 50), series resonance circuits (30, 40), a high-frequency transformer (28) and an energy storage unit (60), wherein the voltage-stabilizing capacitors (22, 32) are used for enhancing the stability of a DC voltage; the high-frequency converters (20, 50) have the same structure and comprise four switching elements inversely connected in parallel with a rapid diode and can be used for inversion and rectification; the series resonance circuits are used for converting three kinds of discrete levels output by corresponding high-frequency converters into sinusoidal waveforms and can be used for softly switching the switching elements of the corresponding high-frequency converters, at the same time, only one series resonance circuit (30 or 40) acts; and the high-frequency transformer (28) can be used for isolation and transformation. The transformer (100) can be used for greatly converting the DC voltage, has high efficiency, and can be applied to an electric vehicle power supply, standby power supplies of large-scale equipment, and the like.

Buck converters having a resonant inductor Lr, resonant capacitor Cr, and synchronous switch Q3 that together provide reduced switching loss and soft switching. In operation, the resonant inductor Lr is charged during a time period A. Then, Lr is freewheeling and provides current to an output inductor Lo. Then, Q3 is turned OFF, and energy from the resonant inductor Lr charges the resonant capacitor Cr. Finally, energy from the resonant capacitor Cr is provided to the output inductor and load. The output power can be adjusted by phase control of the operation of switch Q3. In alternative embodiments, the circuit has a pair of coupled inductors L1 L2 or an isolation transformer 40. The coupled inductors have a polarity selected so that the output voltage is reduced, thereby allowing top switch Q1 to have a greater duty cycle. These circuits feature no body diode loss in the switch Q3.

The method of the invention in one aspect involves electronic power control by varying the amplitude of an electrical power supply voltage, independent of frequency, whereby the output frequency will always be the same as the input frequency. An electrical circuit apparatus for accomplishing this function in a specific embodiment is also disclosed herein. The specific circuitry of this aspect of the invention uses eight solid state switches, such as IGBT's, eight diodes, an inductor, input and output filters and novel controlling circuitry. The controller apparatus and methods of the invention may be used to implement all otherwise conventional converter types, buck, boost, and inverting (and duals of these) versions to obtain different regulating characteristics, including galvanic isolation of the output from the input. Indeed, the eight-switch controller can act to either buck or boost the input voltage, and can switch between bucking and boosting during a cycle, thus providing more control of the regulated output voltage. The inventive methods and devices may be used in power factor correction, voltage and / or current harmonic filtering and neutralization, line and load conditioning, control of power transfer between two power grids, and programmable control of surges, sags, dropouts and most other voltage regulation problems.

A system and method for power conversion synchronizes multiple phases at a desired phase angle difference. The power conversion involves variable frequency switching, fixed on-time and provides power factor correction. A relative measure of a phase angle difference between two phases permits each phase to be controlled to obtain the desired phase angle difference. The power conversion involves transition mode switching to help reduce switching losses. A phase angle difference detector may be provided for each phase. The various phases may have different inherent frequencies that vary with switching frequency, and are synchronized to an average frequency. Current measures can be taken with a single component, such as a resistor. A maximum frequency control limits period width to avoid high frequency switching. An added switch on time improves input voltage crossover distortion. One or more phases can be deactivated in light load conditions.

The present invention aims to provide a synchronous motor drive system that is capable of suppressing ripples in current while reducing switching loss. The system includes three-phase inverters 201-203, a control circuit 400 for controlling the operations of the three-phase inverters and a synchronous motor 300 including a plurality of three-phase coils. To control the operations of the three-phase inverters, the control circuit 400 causes the three-phase inverters 201 and 203 and the three-phase inverter 202 to use different carrier frequencies to generate three-phase AC power, and each of the three-phase inverters supplies a different one of the three-phase coils with three-phase AC power.

A control circuit provides a control signal for a constant on-time PWM switching converter to produce an output voltage, such that the converter operates with a constant on-time at a first state and operates with a variable on-time at a second state, so as to decrease the switching frequency and thereby the switching loss, to increase the efficiency of the converter, to improve the transient response, and to reduce the recovery time of the output voltage.

A switching power source comprises a current comparator 27 for comparing a voltage level of signals acquired by a current detector 9 with a reference voltage level VDT to produce detection signals VCP of first or second level L or H; an edge detector 28a for sensing an edge of drive singal VG supplied to a gate terminal of MOS-FET 3 during the period of transition from turning on to off of MOS-FET 3; and a decision means 28b for receiving a current detection signal VCP from current comparator 27 to produce an output signal VLD when edge detector 28a catches an edge of drive signal VG; wherein decision means 28b produces different output signals VLD of respectively first and second voltage levels L and H under the light and heavy load conditions to precisely and certainly detect on the primary side of transformer 2 the load condition on the secondary side of transformer 2 for improvement in conversion efficiency.

The present invention relates to a method and to a device for adapting the alternating current generated by a generator (1) and the alternating voltage generated by a generator (1) to a grid (8), whereby the generator (1) has at least one excitation coil (2). The power fed into the grid (8) can be flexibly adapted while entailing low switching losses in that a static frequency converter (9) is employed for the adaptation between the generator (1) and the grid (8), and in that, in order to control the power fed into the grid (8), means (3) are provided with which, on the one hand, the strength of the excitation field generated by the at least one excitation coil (2) is regulated and, on the other hand, the phase angle between the frequency converter voltage and the generator or grid voltage is appropriately controlled.

The invention discloses a submodule topology for a modular multi-level transverter. The submodule topology comprises a first switching module, a second switching module, a direct current capacitor and a third switching module, wherein the first switching module and the second switching module are connected in series, the negative end of the first switching module is connected with the positive end of the second switching module, and the first switching module and the second switching module are formed by connecting full-controlled devices and diodes in an antiparallel mode. The positive electrode and the negative electrode of the direct current capacitor are connected with the positive end of the first switching module and the negative end of the second switching module. The third switching module is electrically connected with the first switching module and the second switching module, so that a full-controlled device of the third switching module applies trigger pulses all the time during normal operation and is in a conducting state all the time, and currents of direct current faults can be blocked by locking the trigger pulses of the third switching module when direct current faults happen. The invention further comprises the transverter comprising a submodule and application of the transverter. By means of the submodule topology for the modular multi-level transverter and application of the modular multi-level transverter, a function of isolating the direct current faults is achieved, quantity and switching losses of switching devices in the submodule are decreased, and requirements on trigger simultaneity are reduced.

The method of the invention in one aspect involves electronic power control by varying the amplitude of an electrical power supply voltage, independent of frequency, whereby the output frequency will always be the same as the input frequency. An electrical circuit apparatus for accomplishing this function in a preferred embodiment is also disclosed herein. The preferred circuitry of this aspect of the invention uses four solid state switches, such as IGBT's, four diodes, an inductor, input and output filters and novel controlling circuitry. The controller apparatus and methods of the invention may be used to implement all otherwise conventional converter types, buck, boost, and inverting (and duals of these) versions to obtain different regulating characteristics, including galvanic isolation of the output from the input. The inventive methods and devices may be used in power factor correction, voltage and / or current harmonic filtering and neutralization, line and load conditioning, control of power transfer between two power grids, and programmable control of surges, sags, dropouts and most other voltage regulation problems.

It is aimed at decreasing losses not only in a synchronous rectifier circuit provided at a secondary side of a DC-DC converter, but also in a full-bridge switching circuit provided at a primary side thereof. The DC-DC converter comprises a transformer for voltage conversion, a synchronous rectifier circuit at the secondary side, and a full-bridge switching circuit at the primary side. The DC-DC converter performs synchronous rectifier control which uses switch transistors to change paths of currents flowing through the secondary coil in synchronization with switching operations at the primary side. The DC-DC converter detects currents flowing through a load at the secondary side, primary-side currents varying with the load currents, or primary-side input voltages to dynamically control off-timings of a synchronous rectification transistor at the secondary side. In addition, the DC-DC converter detects primary-side input voltages and currents flowing through the secondary-side load to dynamically control on-timings of a transistor in the primary-side switching circuit.

An apparatus is provided to control a three-phase AC motor and comprises an inverter and a controller. The inverter powers the motor in response to a three-phase PWM command. The control circuit controls the inverter based on two modulation techniques selectively switched from one the other depending on information indicative of an operation state of the motor. One modulation technique gives the PWM command a first two-phase modulation allowing each phase voltage to be fixed at a predetermined voltage level in turn at intervals of an electrical angle of 2π / 3. The other modulation technique gives the PWM command a second two-phase modulation allowing each phase voltage to be fixed at a predetermined voltage in turn at intervals of an electrical angle of π / 3. The switchover can be made between the two-phase and three-phase modulations or can be made with consideration of temperature at switching elements.

In a power converter in which semiconductor modules are arranged on both surfaces of a cooler for downsizing, an excellent connection between control boards and a low inductance connection between smoothing capacitors and the semiconductor modules are performed at the same time. The semiconductor modules are disposed on both surfaces of the cooler, and control boards that control the semiconductor modules are arranged opposite to the respective semiconductor modules. The semiconductor modules and the cooler are held between the control boards. A current detector or a terminal block is disposed at a position perpendicular to a surface on which the cooler and the semiconductor modules contact each other, opposite to the cooler. The respective control boards disposed on both surfaces of the cooler are electrically connected by using wirings provided in the current detector or the terminal block.

A controller for controlling a reactive series compensator serially inserted at compensator terminals into a power transmission line for controlling the line current. The controller includes a current control loop and a voltage control loop. A current controller outputs a control voltage (cc.sub.out) indicating a desired compensator terminal output voltage (u.sub.c). A control method selector means generates, in a low output voltage region, a constant reference voltage (u.sub.DC.sup.ref) for the voltage control loop and a variable modulation index mq of a modulation signal m=m.sub.d cos (.omega.t) -m.sub.q sin (.omega.t). In a high output voltage range, the control method selector outputs a constant modulation index m.sub.q and a variable reference voltage (u.sub.DC.sup.ref). The voltage controller outputs the modulation index m.sub.d of the modulation signal m. Furthermore, the control method selector can include a rate limiter for limiting the change rate of the reference voltage (u.sub.DC.sup.ref). In connection with the control method selection and / or the rate limiter, a decoupling control for making the voltage and current control loops independent from each other can be used. The controllers find particular application in transformerless reactive series compensators for single-phase or three-phase control.