37results about How to "Small current ripple" patented technology

The invention provides a control method applied to a bidirectional isolation full-bridge current transformer for battery energy storage, and aims at the current-voltage type bidirectional isolation full-bridge current transformer, a current-mode full bridge is connected at a battery side, and a voltage-mode full bridge is connected at an inverter side. According to pulse generation method of two H-bridges, the control of the bidirectional isolation full-bridge current transformer becomes simple. A current-mode H-bridge utilizes PWM (pulse-width modulation) to guarantee the current continuity of input inductance and control the transitive power; and a voltage-mode H-bridge utilizes phase shift control to match and finish the bidirectional flow of power. Phase shift between carriers of an original secondary side H-bridge is controlled, so that the power of the bidirectional isolation full-bridge current transformer is only related to the current-mode PWM duty cycle, and power control of the bidirectional isolation full-bridge current transformer can be finished only by using a single PI ring. The control method provided by the invention is simple and practical, and lays a basis for the application of the bidirectional isolation full-bridge current transformer in battery energy storage.

The invention relates to an electric automobile sliding prevention control method, a device, a system and a storage medium. The state of an electric automobile is monitored and comprises an accelerator signal, a speed signal, a brake signal and a gear signal of the electric automobile. Whether a sliding prevention signal is generated by triggering or not is judged according to the state. A motor of the electric automobile is controlled to work in a speed control mode if the sliding prevention signal is generated, the speed is preset to be 0, the pulse number of backward sliding of the electricautomobile within unit time serves as closed loop feedback, a closed loop preset value is 0, the difference value of the closed loop feedback value and the closed loop preset value is proportionallyadjusted and then overlaid on speed loop output, sliding prevention adjusting time is greatly shortened, and backward sliding distance is shortened.

The invention relates to a disc-type coreless permanent-magnet synchronous motor controller based on a current inverter and a method. The disc-type coreless permanent-magnet synchronous motor controller comprises a control circuit, a three-phase inverting circuit and a step-down chopper circuit, wherein the three-phase inverting circuit is used for driving a disc-type coreless motor, and the signal input end of the three-phase inverting circuit is connected with the signal output end of the control circuit; the control signal input end of the step-down chopper circuit is connected with the signal output end of the control circuit, and the current output end of the step-down chopper circuit is connected with the current input end of the three-phase inverting circuit through an inductor L; the output shaft of the disc-type coreless motor is connected with the signal input end of the control circuit through an angle sensor; and the three-phase current outputs of the three-phase inverting circuit are respectively connected with the signal input end of the control circuit through a current sensor. The controller controls the speed regulation of the disc-type coreless permanent-magnet synchronous motor and increases the maximum speed of the motor. The controller has the characteristics of small current pulsation, good sinusoidal performance, convenience in energy feedback and the like.

The invention discloses a wide-voltage-input efficient direct-current power converter for an aerostat. The wide-voltage-input efficient direct-current power converter comprises a SuperBuck circuit, a push-pull circuit, a closed-loop control circuit and a diode used for achieving the series connection of the output end of the SuperBuck circuit and the output end of the push-pull circuit, wherein the SuperBuck circuit is composed of an inductor, a capacitor, a diode and a switch tube, and the push-pull circuit is composed of a switch tube, a boosting transformer, a rectifier diode and a filter capacitor. The wide-voltage-input efficient direct-current power converter for the aerostat has the advantages that the polarity of input voltages and the polarity of output voltages are identical, a main circuit device is simple, input currents and output currents are consecutive, input and output are common-grounded, current pulses caused to a power supply bus and a storage battery are small, and smooth switching of voltage boosting and voltage reduction can be achieved.

The invention discloses a three-level full-bridge DC conversion device. A low-voltage diode can be directly adopted by a secondary rectifier side of a transformer of the three-level full-bridge DC conversion device to achieve high voltage output, and meanwhile, the problem of non-uniform voltage, caused by the reverse recovery inconsistency, of the diode which is directly connected in series is solved. In most of the switching period, a secondary rectifier diode is clamped by a secondary flying capacitor, so that voltage oscillation and spikes on the diode can be eliminated without adding an auxiliary circuit and reduction of the volume and improvement of the conversion efficiency are facilitated. Output voltage of a secondary rectifier bridge has certain DC bias, the secondary rectifier bridge can output higher voltage than a conventional rectifier circuit, and current ripples on an output filter inductor are smaller, so that improvement of the DC voltage utilization ratio and the power density of the device is facilitated and the volume and the weight of the device are reduced.

A switching type power source device used for magnetic field generation coils for an MRI device in which a switching power sources ( 9-11 ) are constituted by a first and a second multi level PWM inverter ( 12,13 ) having a same number of potential levels connected in parallel each other with respect to magnetic field generating coils ( 6-8 ) for the MRI device working as a load as well as a switching control circuit ( 19 ) for drive controlling the first and the second multi level PWM inverter ( 12,13 ) is constituted to drive control the first and the second multi level PWM inverter ( 12,13 ) in a manner to shift the switching phases thereof each other, thereby, ripple components in currents output from the first and the second multi level PWM inverter ( 12,13 ) are canceled out each other and a current with a further reduced ripple components as a whole can be supplied to the load ( 6-8 ).

The invention discloses a controller for a digitalized proportional valve with high switching frequency. The controller comprises a microprocessor, a communication port, a drive circuit, a power amplification circuit, a position detection circuit and a circuit detection circuit. The communication port is connected with the microprocessor in a bidirectional communication mode, the position detection circuit and the current detection circuit are connected with analog-digital conversion interfaces of the microprocessor respectively, the microprocessor is connected with the power amplification circuit through the drive circuit, and the power amplification circuit is in electric connection with an electromagnetic coil of the proportional valve. The invention further discloses a control method of the controller for the digitalized proportional valve with high switching frequency. The method comprises the steps that the microprocessor receives a position setting signal and a current setting signal through the communication port, and whether position closed-loop control and current closed-loop control or only the current closed-loop control is adopted in the controller for the proportional valve is judged through a selection switch. By means of the control method, the working modes can be selected according to the actual working demands, and good flexibility and adaptability are achieved.

The invention relates to a stepless speed regulation device for a working table or a spindle of a numerical control machine tool. The device comprises a speed regulator, a current regulator, a triangular wave generator, a pulse width modem, a transistor amplification circuit, a current signal amplifier and a speed measurement feedback circuit. The speed regulator, the current regulator, the pulse width modem and the transistor amplification circuit are connected sequentially. The triangular wave generator is connected with the pulse width modem, the input end of the current signal amplifier is connected with the output end of the transistor amplification circuit, the input end of the current signal amplifier is connected with the input end of the current regulator, and the speed measurement feedback circuit for measuring the rotation speed of a motor is connected with the input end of the speed regulator. The device has the advantages that the bandwidth is wide, and the frequency is high; the transistor 'junction capacitance' is small, and the rapidity is good; the current pulsation is small, and the power factor of a power supply is high; a direct-current power supply of a PWM system is uncontrolled rectification output, the power factor is good, and the dynamic hardness is good.

The invention relates to an insulated gate bipolar translator (IGBT) clamping three-level frequency converter, and belongs to the field of frequency converters. A main circuit of the IGBT clamping three-level frequency converter is a three-phase six-bridge arm frequency converting circuit; each of a first bridge arm, a second bridge arm, a third bridge arm, a fourth bridge arm, a fifth bridge arm and a sixth bridge arm comprises three switching elements, wherein the first bridge arm and the second bridge arm are connected with a phase W of an output circuit; the third bridge arm and the fourth bridge arm are connected with a phase V of the output circuit; the fifth bridge arm and the sixth bridge arm are connected with a phase U of the output circuit; and each of the phase W, the phase V and the phase U is provided with six free-wheeling diodes and two series energy storage capacitors. By clamping connection and disconnection of an IGBT, the frequency converter solves the problem that the waveform quality of the output voltage is affected by unequal upper and lower capacitor voltages and midpoint potential drift when a certain phase of output voltage in three phases of output voltages is zero, current flows into or flows out of a direct-current capacitor midpoint and the inflow current is unequal to the outflow current.

The invention discloses a double-vector-based winding open-circuit permanent magnet synchronous motor current prediction control method and device. According to the method, the reference voltage vector of a motor is calculated on the basis of a current dead beat principle; the voltage vectors of a first inverter are determined according to the position of the reference voltage vector; the reference voltage vector of a second inverter can be calculated on the basis of a relationship between the motor voltage vector and the inverter voltage vector; two non-zero vectors are determined according to the position of the reference voltage vector of the second inverter within the vector hexagon of the second inverter, so that the range and number of the candidate voltage vectors of the second inverter are obtained; the voltage vectors of the second inverter are combined in pairs, so that an optimal vector combination is determined through calculation; and the voltage vectors of the first inverter and the voltage vectors of the second inverter are outputted in a combined manner. Thus, zero-sequence current during winding open-circuit permanent magnet synchronous motor current prediction canbe effectively suppressed, current ripples are reduced, steady state performance is improved, and test costs are reduced.

The invention provides a synchronous switched reluctance motor, mainly comprising a three-phase stator, a salient pole rotor, a rotor position sensor, a casing, a motor controller and a shaft, whereinthe three-phase stator adopts a three-phase concentrated winding or a three-phase distributed winding and generates a synchronous rotating magnetic field under the driving control of the motor controller, and the strength and rotating speed of the synchronous rotating magnetic field can be controlled by the motor controller through the three-phase stator; the salient pole rotor does not include apermanent magnet or a squirrel cage structure, does not need to open a reluctance groove, is formed by laminating only silicon steel sheets and has an even number of salient poles; the three-phase stator is mounted inside the casing, the salient pole rotor is mounted on the shaft and mounted on the casing through the shaft, and the rotor position sensor is mounted at one end of the shaft; and thethree-phase stator and the salient pole rotor constitute a radial magnetic circuit. The novel synchronous switched reluctance motor not only retains the advantages of simple structure of a switched reluctance motor and the advantages of small torque ripple and low noise of a synchronous reluctance motor, but also overcomes the large torque ripple of the switched reluctance motor and the complicated structure of the synchronous reluctance motor.

The invention relates to an alternative-boost-buck-circuit-based voltage equalizer comprising a direct-current link, a bidirectional alternative boost-buck converter, an output filter circuit and a load. A positive terminal and a negative terminal of the bidirectional alternative boost-buck converter are respectively hooked to a positive potential link and a negative potential link of the direct-current link and a common terminal of the bidirectional alternative boost-buck converter and a capacitance common terminal of the output filter circuit are connected to form a neutral line, thereby forming a dual-polarity bus distribution mode. According to the voltage equalizer provided by the invention, with the alternative control technology, the power level can be increased conveniently and the current pulse of the direct-current link can be effectively reduced, thereby reducing the decoupling capacitance of the direct-current link. Meanwhile, currents flowing through the neutral point almost have no pulsation, so that the filter capacitance can be substantially reduced. The alternative-boost-buck-circuit-based voltage equalizer is suitable for a distribution system of a direct-current micrgrid as well as a bipolar bus distribution power supply system on a ship or a plane, especially for an aerospace direct-current distribution system with a strict size requirement.

A system and method for reducing drive motor speed ripple of an electric vehicle are provided. The system includes an inverter that converts DC power supplied from a battery to AC power and supplies the AC power to the drive motor by inverter switching. A resolver is configured to detect a speed of the drive motor and a position of a rotor, a signal generator includes a microcontroller that is configured to generate a square wave signal. An integrator is configured to convert the square wave to a sine wave, and apply a sine-wave excitation input signal to the resolver. Furthermore, a motor controller is configured to adjust the frequency of the excitation input signal to prevent the inverter switching frequency of the inverter and the peaks of an output voltage signal sampled for speed calculation from overlapping.

The invention belongs to the technical field of power supply of power sources, and provides a positive and negative output DC-DC power source structure based on Boost. The structure comprises a Boostconversion structure, and the Boost conversion structure comprises an input direct current power source Vin, an inductor L1, a diode D1, a switching tube Q1 and an energy storage filter capacitor C2;a capacitor C1 and a diode D2 which are in series connection with each other are inserted into a switching node between the inductor L1 and the diode D1, and a diode D3, an inductor L2 and an energy storage filter capacitor C3 which are in series connection are connected into a series-connection node of the capacitor C1 and the diode D2, and two output ends of negative voltage are draw forth fromthe two ends of the energy storage filter capacitor C3; a negative electrode of the diode D3 is connected with the capacitor C1, a positive electrode of the diode D2 is connected with the capacitor C1, and the capacitor C1, the inductor L2 and the energy storage filter capacitor C3 constitute an LC filter circuit. By means of the positive and negative output DC-DC power source structure, a switching tube or a switching control chip does not need to be additionally arranged, the circuit structure is simple, and the cost is low; the structure has a high current output capability and small current pulsation, and the positive voltage and negative voltage are nearly symmetric.

The invention discloses a permanent magnet synchronous motor control method and system, wherein current pulsation is reduced and steady-state performance is improved while common-mode voltage is suppressed compared with a traditional single-vector MPC, and algorithm complexity is reduced and calculated amount is reduced compared with an existing double-vector MPC. The method comprises the steps ofcollecting mechanical and electrical parameters of a permanent magnet synchronous motor at the current moment; calculating to acquire a rotation reference voltage vector of a synchronous rotation coordinate system, and converting the rotation reference voltage vector into a static reference voltage vector of a static coordinate system; determining a sector of the static reference voltage vector in a plane where a basic voltage vector is located; selecting two effective vectors from the plane vectors according to the sector, and synthesizing to acquire a synthesized vector; calculating a firstdistance and a second distance from the static reference voltage vector to the side where the zero vector and the synthesized vector are located; selecting an alternative vector according to the first distance and the second distance; and calculating the action time of the alternative vector, determining the action time of all the basic voltage vectors, and controlling the permanent magnet synchronous motor.

The invention discloses a low-input-current-ripple high-gain low-loss modular photovoltaic direct-current boost converter, and belongs to the technical field of power generation, power transformation or power distribution. The converter comprises N isolated photovoltaic sub-modules and N-1 LC power balancing units. The isolated photovoltaic sub-module comprises a photovoltaic cell panel and a current source type dual-active bridge converter with a buck-boost characteristic, the current source type dual-active bridge converter with the buck-boost characteristic is adopted to reduce input and output current ripples, the voltage gain is high, and the isolated photovoltaic sub-module is suitable for a wide voltage gain occasion. And the loss of the converter is greatly reduced due to relatively small current stress and soft switching working characteristics. The photovoltaic sub-modules reuse devices in secondary full-bridge circuits, independent MPPT control of the photovoltaic sub-modules is realized by controlling a phase shift angle between primary and secondary circuits, power transmission between adjacent sub-modules is realized by controlling a phase shift angle between secondary full bridges of the adjacent sub-modules, and power balance between the sub-modules is realized. The number of used switching devices is reduced, and cost is greatly reduced.

The invention discloses a method for determining an optimal voltage vector of a permanent magnet synchronous wind driven generator, and the method specifically comprises the steps: collecting the real-time data of a generator, and calculating the dq-axis component of a stator voltage given value at a moment k; calculating a dq-axis component of the synthesized voltage vector us; constructing a cost function; calculating duty ratios dmi and dni of two adjacent effective voltage vectors umi and uni of the ith sector; when dmi is smaller than 0 or dni is smaller than 0, the function of the corresponding effective voltage vector is canceled, when dmi is larger than 1 or dni is larger than 1, the corresponding effective voltage vector acts on the whole sampling period, and when dmi is larger than or equal to 0 and smaller than or equal to 1 or dni is larger than or equal to 0 and smaller than or equal to 1, duty ratios dmi and dni are redistributed; and selecting two adjacent effective voltage vectors umi and uni which enable the cost function to be minimum. The stator current pulsation and static error of the permanent magnet synchronous wind driven generator can be effectively reduced, and the dynamic and static performance of the system is improved.

The invention discloses an LED drive circuit based on constant-ON-time control. The LED drive circuit is characterized by comprising a Regulator module, an ON_TIMER module, an OFF_TIMER module, a COMP module, a detection resistor R and a power tube. The LED drive circuit can be widely applied to occasions including general LED illumination, large power LED street lamp illumination, solar LED landscape lamps and car light illumination, is a large power LED illumination drive circuit with high market values, and solves the problems that the switching frequency changes with the input voltage, the ripples are high and the structure is complex in a common LED circuit.

The invention discloses a controller for a digitalized proportional valve with high switching frequency. The controller comprises a microprocessor, a communication port, a drive circuit, a power amplification circuit, a position detection circuit and a circuit detection circuit. The communication port is connected with the microprocessor in a bidirectional communication mode, the position detection circuit and the current detection circuit are connected with analog-digital conversion interfaces of the microprocessor respectively, the microprocessor is connected with the power amplification circuit through the drive circuit, and the power amplification circuit is in electric connection with an electromagnetic coil of the proportional valve. The invention further discloses a control method of the controller for the digitalized proportional valve with high switching frequency. The method comprises the steps that the microprocessor receives a position setting signal and a current setting signal through the communication port, and whether position closed-loop control and current closed-loop control or only the current closed-loop control is adopted in the controller for the proportional valve is judged through a selection switch. By means of the control method, the working modes can be selected according to the actual working demands, and good flexibility and adaptability are achieved.

The invention relates to an electric automobile sliding prevention control method, a device, a system and a storage medium. The state of an electric automobile is monitored and comprises an accelerator signal, a speed signal, a brake signal and a gear signal of the electric automobile. Whether a sliding prevention signal is generated by triggering or not is judged according to the state. A motor of the electric automobile is controlled to work in a speed control mode if the sliding prevention signal is generated, the speed is preset to be 0, the pulse number of backward sliding of the electricautomobile within unit time serves as closed loop feedback, a closed loop preset value is 0, the difference value of the closed loop feedback value and the closed loop preset value is proportionallyadjusted and then overlaid on speed loop output, sliding prevention adjusting time is greatly shortened, and backward sliding distance is shortened.

The invention discloses a wide-voltage-input efficient direct-current power converter for an aerostat. The wide-voltage-input efficient direct-current power converter comprises a SuperBuck circuit, a push-pull circuit, a closed-loop control circuit and a diode used for achieving the series connection of the output end of the SuperBuck circuit and the output end of the push-pull circuit, wherein the SuperBuck circuit is composed of an inductor, a capacitor, a diode and a switch tube, and the push-pull circuit is composed of a switch tube, a boosting transformer, a rectifier diode and a filter capacitor. The wide-voltage-input efficient direct-current power converter for the aerostat has the advantages that the polarity of input voltages and the polarity of output voltages are identical, a main circuit device is simple, input currents and output currents are consecutive, input and output are common-grounded, current pulses caused to a power supply bus and a storage battery are small, and smooth switching of voltage boosting and voltage reduction can be achieved.

The invention relates to a single-stage bridgeless boost Cuk resonant LED drive circuit, comprising a bridgeless boost Cuk circuit unit and an LLC circuit unit, wherein a lower switch tube in the LLC circuit unit and a bridgeless boost Cuk circuit unit The switch tubes share a power switch tube, and the bridgeless boost Cuk circuit and the LLC circuit are integrated into a single-stage AC-DC drive circuit by multiplexing the power switch tube. where the input AC power supply V in , power diode D 1 ~D 6 and D 8 , inductance L 1 , L 2 and L 3 , the intermediate capacitor C 1 and C 2 , bus capacitance C bus , the second power switch tube S 2 Constitute a bridgeless boost Cuk circuit unit; power diode D 7 , D9‑D 12 , Power switch tube S 1 , S 2 , resonant inductance L r , resonant capacitor C r , high frequency transformer T with center tap on secondary side, output capacitor C 0 It constitutes an LLC circuit unit. The invention realizes the bridgeless single-stage PFC circuit and the ZVS soft switching through the multiplexing of the bridgeless boosting Cuk PFC circuit and the LLC circuit switch tube, and reduces the conduction loss and switching loss of the main circuit of the converter.

The invention discloses a low-current pulsation duty ratio optimization method for a direct-driven permanent magnet wind driven generator, and the method specifically comprises the steps: collecting the real-time data of a generator, and calculating the reference voltage of a dq axis; according to the reference voltage phase angle, calculating the sector of the reference voltage phase angle; solving a first-order partial derivative of the vector duty ratio to obtain the duty ratios alpha g1 and alpha g2 of two adjacent vectors; when the alpha g1 and the alpha g2 are smaller than 0, the action of the corresponding voltage vector is cancelled, when the alpha g1 and the alpha g2 are larger than 1, the voltage vector with the vector duty ratio larger than 1 acts on the whole period, and when the alpha g1 and the alpha g2 are in the range of [0, 1], the vector duty ratio is redistributed; and the three-phase duty ratio of the generator is redistributed. Generator stator current pulsation can be effectively reduced, and the stability of the system is improved.

The invention provides a PFC circuit and method for dynamically adjusting switching frequency, and the circuit comprises a PFC control chip, and a switching frequency programming pin of the PFC control chip is externally connected with an equivalent resistor Rf; the PFC control chip is grounded based on a grounding pin, is connected with the Vcc based on a power supply pin to supply power, and isconnected with a gate pole Gate of a power switching device of the PFC circuit based on a driving signal output pin; and the equivalent resistor Rf is composed of a first fixed resistor R1, a second fixed resistor R1 and a PTC resistor RPTC, and the resistance value of the equivalent resistor Rf is determined by the temperature of the power switch device according to the resistance value of the PTC resistor RPTC. According to the power switching device for protecting the PFC circuit, the switching frequency is improved and the current pulsation in the switching period is reduced during light load, so that the current ripple rate, the current ripple and the EMC noise are reduced, and the switching frequency, the switching loss and the temperature rise of the power switching device are dynamically reduced in real time according to the temperature rise of the power switching device during heavy load; and power switching device lifetime is enhanced.

The invention discloses a 3300v frequency converter adopting a phase voltage frequency conversion technology. The 3300v frequency converter adopts an input 3300v transformer and comprises a first input circuit, a second input circuit and a third input circuit; the first input circuit is a R-O input circuit; the second input circuit is an S-O input circuit; the third input circuit is a T-O input circuit; a first output circuit, a second output circuit and a third output circuit correspond to the first input circuit, the second input circuit and the third input circuit, respectively. As the rectification and inversion power devices of the frequency converter are arranged according to a special topology structure, the 3300v frequency converter adopting the phase voltage frequency conversion technology obtains an effect of driving a 3300v motor by using a 4500v withstand voltage level IGBT.

Embodiments of the present invention provide a method and a device for detecting a rotor position of a permanent magnet synchronous motor and a ventilation treatment device. The method comprises the steps of: measuring a three-phase current and three-phase output voltage of the permanent magnet synchronous motor, wherein the three phases of the permanent magnet synchronous motor are respectively connected in series with test inductors; performing coordinate transformation of the three-phase current and the three-phase output voltage to obtain a two-phase current and a two-phase output voltagein a two-phase stationary coordinate system; according to the two-phase current, the two-phase output voltage, the inductors of the permanent magnet synchronous motor and the inductors of the test inductors, obtaining the two-phase counter electromotive force in the two-phase stationary coordinate system; and according to the two-phase counter electromotive force, obtaining the rotor position of the permanent magnet synchronous motor. According to the embodiment of the invention, the current ripple of the permanent magnet synchronous motor is reduced, the observation precision of the two-phasecounter electromotive force is improved, and the detection accuracy of the rotor position of the permanent magnet synchronous motor is further improved.

The invention relates to a disc-type coreless permanent-magnet synchronous motor controller based on a current inverter and a method. The disc-type coreless permanent-magnet synchronous motor controller comprises a control circuit, a three-phase inverting circuit and a step-down chopper circuit, wherein the three-phase inverting circuit is used for driving a disc-type coreless motor, and the signal input end of the three-phase inverting circuit is connected with the signal output end of the control circuit; the control signal input end of the step-down chopper circuit is connected with the signal output end of the control circuit, and the current output end of the step-down chopper circuit is connected with the current input end of the three-phase inverting circuit through an inductor L; the output shaft of the disc-type coreless motor is connected with the signal input end of the control circuit through an angle sensor; and the three-phase current outputs of the three-phase inverting circuit are respectively connected with the signal input end of the control circuit through a current sensor. The controller controls the speed regulation of the disc-type coreless permanent-magnet synchronous motor and increases the maximum speed of the motor. The controller has the characteristics of small current pulsation, good sinusoidal performance, convenience in energy feedback and the like.

The present invention provides a PFC circuit and method for dynamically adjusting the switching frequency, comprising: a PFC control chip, the switching frequency programming pin of the PFC control chip is externally connected with an equivalent resistance R f ; The PFC control chip is grounded based on the ground pin, powered based on the connection between the power supply pin and Vcc, based on the drive signal output pin and the gate gate of the power switching device of the PFC circuit; the equivalent resistance R f by the first fixed resistor R 1 , the second fixed resistor R 1 and PTC resistor R PTC composition, the equivalent resistance R f The resistance is the PTC resistor R PTC The resistance value is determined by the temperature of the power switching device. The invention is used to protect the power switching device of the PFC circuit. At light load, the switching frequency is increased, and the current ripple in the switching cycle is reduced, thereby reducing the current ripple rate, improving the current ripple, and reducing EMC noise. According to the temperature rise of the power switch device, the switching frequency of the power switch device is dynamically reduced in real time, the switching loss is reduced, the temperature rise is reduced, and the life of the power switch device is improved.

The invention provides a control method applied to a bidirectional isolation full-bridge current transformer for battery energy storage, and aims at the current-voltage type bidirectional isolation full-bridge current transformer, a current-mode full bridge is connected at a battery side, and a voltage-mode full bridge is connected at an inverter side. According to pulse generation method of two H-bridges, the control of the bidirectional isolation full-bridge current transformer becomes simple. A current-mode H-bridge utilizes PWM (pulse-width modulation) to guarantee the current continuity of input inductance and control the transitive power; and a voltage-mode H-bridge utilizes phase shift control to match and finish the bidirectional flow of power. Phase shift between carriers of an original secondary side H-bridge is controlled, so that the power of the bidirectional isolation full-bridge current transformer is only related to the current-mode PWM duty cycle, and power control of the bidirectional isolation full-bridge current transformer can be finished only by using a single PI ring. The control method provided by the invention is simple and practical, and lays a basis for the application of the bidirectional isolation full-bridge current transformer in battery energy storage.