13results about How to "Increase the switching frequency" patented technology

The invention discloses a multi-standard power supply system and method for a locomotive test, and relates to the technical field of test power supplies, and the structural design of the system is as follows: an input power supply is a three-phase alternating current 10kV power supply; the high-voltage switch K realizes access control and isolation of the system and a public power grid, the connection reactor L realizes energy buffering and inhibits switch ripples in output current, and the soft charging circuit pre-charges the three-stage converter. The three-level converter converts three-phase alternating current 10kV into DC1500 / 750V and outputs the DC1500 / 750V to the direct-current bus, one path of the direct-current bus supplies power to a subway vehicle test line, and the other path of the direct-current bus is inverted into single-phase alternating current 25kV through the output inverter and supplies power to a railway locomotive test line. According to the invention, alternating current test conditions of railway electric traction locomotive vehicles and direct current test conditions of subway vehicles can be satisfied, reliability and quality of power supply are ensured, repeated construction is reduced, and resource waste is avoided.

The invention discloses a hybrid control method and system for an interleaved flyback photovoltaic micro inverter. The method comprises the following steps: S1, acquiring a real-time photovoltaic panel voltage, a power grid voltage effective value, a power grid phase and the average output power of the inverter; s2, calculating a gain factor based on the voltage of the photovoltaic panel and the phase of the power grid; s3, according to the gain factor, the network voltage effective value, the transformer excitation inductance, the average output power and the transformer turn ratio, the duty ratio and the switching frequency under the BCM are calculated; s4, comparing the switching frequency with a preset limiting frequency of a BCM mode and a preset fixed working frequency of a DCM mode, and selecting a working mode according to a comparison result; and S5, generating a corresponding control signal according to the working mode, wherein the control signal is used for driving a flyback switching tube and a power frequency flip circuit switching tube. The method has the advantages of reducing the calculation burden of mode switching and the like.

The invention provides a PWM wave optimization method and system based on VIENNA rectifier single-period control. The PWM wave optimization method comprises the steps that three-phase input current is sampled; determining the position of the corresponding PWM wave high level in the switching period according to the current direction of each phase; the method specifically comprises the following steps: for each PWM output channel, according to a phase current symbol associated with the PWM output channel, selecting to place a high level at two ends or in the middle of a switching period; and based on the determined PWM high level position and the calculated duty ratio, generating and outputting a PWM driving signal used for controlling a VIENNA rectifier switch tube. According to the method, PWM generation logic is redesigned, a non-optimal voltage vector combination used in traditional synthesis is abandoned, and three vectors (namely vectors corresponding to three vertexes of a small triangle where a target vector is located) closest to the target voltage vector are adopted for synthesis; according to the optimization, on the premise that the switching frequency is not increased and extra hardware cost is not increased, output current harmonics are remarkably reduced.

The application discloses a gallium nitride soft switch high-voltage Buck voltage converter and belongs to the technical field of switching power supplies. The auxiliary soft switch link is introduced, the problem of large switching loss, high thermal stress, large voltage peak and high-frequency oscillation caused by the switching capacitor link in the traditional high-voltage Buck switching capacitor voltage converter is solved, the efficiency and reliability of the system are improved, further, the double-phase staggered parallel structure is introduced, the current output capacity of the power supply is improved, the application in a higher power scene can be realized, meanwhile, the gallium nitride transistor is adopted, compared with the traditional scheme, the switching frequency is improved, the passive element size is reduced, the PCB integration is improved, the system parasitic parameters are reduced, the dead time and duty cycle loss are reduced, and the system efficiency and power density are further improved.

This invention discloses a control method, control device, and switching power supply. The control method employs a variable frequency SVPWM modulation strategy, comprising the following steps: calculating the SVPWM modulation wave for controlling the on / off state of each phase bridge arm switch when the electrical parameters output by the N-phase converter reach the desired value through a dual closed-loop control of the voltage outer loop and current inner loop; calculating the frequency required for each phase bridge arm switch to achieve ZVS by predicting the magnitude of the current ripple of the second filter inductor in each phase, comparing the frequencies of each phase, and selecting the minimum frequency among the N phases as the frequency of the triangular carrier wave; using the calculated frequency to generate a shared triangular carrier wave; and comparing the SVPWM modulation wave of each phase bridge arm switch with the shared triangular carrier wave to obtain a PWM drive signal for controlling the on / off state of each phase bridge arm switch. This invention enables soft switching of each sector through variable frequency, eliminating the need for clamping each phase.

The application discloses a GaN HEMT device integrated with a reverse conduction function and a preparation method thereof, and belongs to the technical field of semiconductor devices. The device comprises a substrate and a buffer layer, a first channel layer, a first barrier layer, an isolation layer, a second channel layer, a second barrier layer and a p-GaN layer which are sequentially stacked; wherein a first recess is formed in the second barrier layer and penetrates to the first channel layer, the bottom of the recess is provided with an anode which forms a Schottky contact with the first channel layer, and a source electrode covers the anode and the first recess; a second recess is formed and penetrates to the first barrier layer, and a cathode which forms an ohmic contact with the first barrier layer is arranged in the recess. The application integrates an independent reverse conduction diode channel in the GaN HEMT device by constructing a double heterojunction structure and a specific recess electrode design, realizes single-chip integration of forward switching and reverse current flow, effectively reduces a reverse conduction voltage drop, eliminates parasitic parameters of an externally-mounted diode, and significantly improves the power density and reliability of a system.

This application discloses a motor drive control method, apparatus, device, storage medium, and product, relating to the field of motor control technology. The disclosed motor drive control method includes: acquiring current motor parameters of a target vehicle under current operating conditions, wherein the motor parameters include an electrical frequency; if the electromagnetic force fluctuation frequency generated by the current harmonic frequency corresponding to the electrical frequency is within the resonant frequency range of the target vehicle, determining a target synchronous modulation scheme corresponding to the electrical frequency from a preset set of synchronous modulation schemes; and controlling the drive circuit of the target vehicle based on the target synchronous modulation scheme. This application uses a flexible synchronous modulation scheme instead of an asynchronous modulation method to avoid increasing the switching frequency, thereby reducing the losses in the new energy vehicle motor drive system.

This invention discloses a control method for a Vienna rectifier topology based on SiC power devices. First, a mathematical model of a three-phase Vienna rectifier is established; then, the expressions for the Vienna rectifier's midpoint voltage and current are derived; an inner current loop is designed; an outer voltage loop is designed; and finally, midpoint potential balance control is performed. This invention can reduce the size of the Vienna rectifier system, improve the power factor, and reduce system losses.

This application relates to the field of switching power supply technology and discloses a gallium nitride (GaN) charger based on a 494 PWM chip. The charger includes a power board, a rectifier circuit module, a half-bridge GaN driver module, a transformer, a 494 chip control module, a totem-pole driver module, an isolation driver transformer, a full-wave rectifier module, a filter circuit module, and a conversion circuit module. The core of this application is that the 494 chip control module generates a PWM signal, which is then amplified by the totem-pole driver module and electrically isolated and coupled by the isolation driver transformer before driving two GaN transistors in the half-bridge topology to switch alternately at high frequency. This application fully utilizes the high-speed switching characteristics of GaN devices, enabling the charger to operate at higher frequencies. This increases the power level to the kilowatt level while reducing switching losses and the size of magnetic components, achieving high power density and high overall conversion efficiency.

The application provides a gallium nitride device, which comprises a closed ring-shaped gate structure, a dielectric layer, a source field plate, at least a part of the source field plate being formed on one of inner and outer side walls of the dielectric layer, a residual field plate, the residual field plate being formed on the other of the inner and outer side walls of the dielectric layer, the residual field plate being left on the dielectric layer after an etching process for forming the source field plate, and a gap between the source field plate and the residual field plate, so that there is no physical contact and no electrical connection between the source field plate and the residual field plate. The gap is naturally formed between the residual field plate and the source field plate, and there is no physical contact and no electrical connection, so that the contribution of the residual field plate to the gate-source capacitance Cgs is eliminated, the switching loss of the device is significantly reduced, and the switching frequency is improved.

The invention discloses a large signal modeling and control method for a high-voltage power supply of an M-module LCC resonant converter. The MCU is arranged on a circuit board, the DC-DC or LDO is used for inputting power to the MCU, the DC-DC booster circuit is connected with 48V input power and is used for boosting the 48V power to a set bus voltage, the inverter driver and the IPOS module are connected with the DC-DC booster circuit, the resonant cavity is connected with the inverter driver and the IPOS module, and the auxiliary power supply is connected with the IPOS module. The MCU is controlled by TMS320F28377D, more complex control logic can be realized through programming, and a complex peripheral circuit required by analog chip control is not needed; according to the LCC resonant converter topology, the system works in an inductive area by controlling the switching frequency and resonance parameters, natural soft switching of a switching device is achieved, additional algorithm control is not needed, and the system efficiency is improved; the natural soft switch enables the switching frequency of the system to be higher, and the high frequency of the system enables the sizes of magnetic elements, capacitors and the like to be small, thereby facilitating the reduction of the size and weight of the system.

The application discloses a preparation method of an n-type gallium nitride-based GAA-HEMT inverter, and comprises the following steps: S1, growing aluminum oxide on a GaN single crystal substrate, etching the middle part of the barrier layer and depositing a metal gate; S2, etching the middle part of the gate to form a groove, depositing aluminum oxide, etching the middle and both sides of the aluminum oxide, growing GaN nanosheets in the etching area, doping Si after growing AlGaN nanosheets, growing GaN nanosheets to form p-GaN nanosheets by doping Mg; S3, etching the p-GaN nanosheets to make the width of the p-GaN nanosheets same as that of the gate, evaporating a metal film in the thickness direction of the two layers of nanosheets to prepare a source electrode and a drain electrode, growing aluminum oxide on the surface of the device to cover the p-GaN nanosheets and the AlGaN nanosheets, depositing a metal gate to cover the aluminum oxide to form an E-mode GaN; and S4, growing aluminum oxide, etching the middle part of the aluminum oxide to deposit a metal gate, and preparing GaN nanosheets, AlGaN nanosheets, a source electrode and a drain electrode in the manner of S2 and S3, growing aluminum oxide to cover the AlGaN nanosheets, depositing a metal gate to cover the aluminum oxide to obtain a D-mode GaN with a GAA structure.

Embodiments of the present application provide a control method and control circuit of a hybrid device, and relate to the technical field of electronics. The hybrid device comprises a first switch tube and a second switch tube connected in parallel. The control method comprises: obtaining a load current; the load current is a current flowing through a load. If the load current is less than a first current, the first switch tube is controlled to be turned on, and the second switch tube is controlled to be turned off; the first current is a turning point current of the first switch tube. If the load current is greater than the first current and less than a second current, the first switch tube is controlled to be turned on, and then the second switch tube is controlled to be turned on; the second current is a maximum pulse current of the first switch tube. If the load current is greater than the second current, the second switch tube is controlled to be turned on, and then the first switch tube is controlled to be turned on; after the first switch tube is controlled to be turned off, the second switch tube is controlled to be turned off. The control method can reduce the operating loss of the hybrid device.