26results about How to "Reduce voltage stress" patented technology

The embodiment of the invention discloses a midpoint potential control method based on a diode clamping type three-level grid-connected inverter and a related device. The method comprises the following steps: generating an initial three-phase modulation wave through a current loop closed-loop control method according to a collected three-phase current value and a three-phase voltage value of a power grid side of the diode-clamped three-level grid-connected inverter; according to an initial modulation waveform generated by the initial three-phase modulation wave, a three-phase current value and an acquired voltage value of a voltage dividing capacitor at the direct current side of the diode clamping type three-level grid-connected inverter, calculating a zero-sequence component required by neutral-point potential balance; superposing a zero-sequence component required by neutral-point potential balance with the initial modulation waveform to obtain a final modulation wave; and generating a driving signal matched with each phase of bridge arm in the diode clamping type three-level grid-connected inverter according to the final modulation wave. By adopting the invention, the neutral-point voltage can be balanced, the distortion of the output waveform at the alternating current side is reduced, the voltage stress of the device is reduced, and the service life of the power device is prolonged.

The invention relates to a distributed photovoltaic power station main converter and a control method thereof, and belongs to the field of photovoltaic power generation. The main current transformer comprises a T-type three-level current transformer and a Buck-Boost current transformer; the T-type three-level converter comprises three bridge arms, two output capacitors and the like; each bridge arm is provided with four power switch tubes; the two output capacitors are connected in series, and the connection point is called as the midpoint O of the T-type three-level converter. And one end of a direct-current inductor of the Buck-Boost converter is connected with the midpoint O. The T-type three-level converter adopts PI control and a carrier pulse width modulation strategy to realize alternating current side current harmonic wave minimization of the T-type three-level converter; the Buck-Boost converter adopts a PI control method to realize neutral-point potential automatic balance control. The method is small in current harmonic wave, low in cost and simple to control, and can realize quick and automatic balance of the neutral-point potential, thereby effectively coping with the influence of illumination and power grid voltage fluctuation on system control, and realizing quick and stable control of the distributed photovoltaic power station.

The invention discloses a multi-mode switching control method suitable for a grid-connected isolation inverter, and the method comprises the steps: in each half power grid voltage period, according to a power grid instantaneous voltage phase Theta g outputted by a phase-locked loop in the isolation inverter, the phase Theta g is within [0, pi], then the phase Theta g is compared with given power grid voltage phases Theta g1 and Theta g2, the Theta g1 and Theta g2 meet the condition that Theta g1 is smaller than or equal to Theta g2, and the Theta g1 is smaller than or equal to Theta g2; a variable-frequency discontinuous conduction mode, namely a variable-frequency DCM mode, is adopted in the ranges of 0 < theta g < theta g 1 and pi-theta g 2 < theta g < pi, a main switching tube of a flyback converter in the isolation inverter is controlled to be switched on when the period is larger than a given switching period and the drain-source voltage valley value, and a critical conduction mode, namely a BCM mode, is adopted in the range of theta g 1 < theta g < pi-theta g 2. And controlling a main switch tube of the flyback converter to be switched on at the drain-source voltage valley value. Different working modes are adopted under different output voltages, so that the switching loss of the isolation inverter in a full-load range is reduced, and the energy conversion efficiency of the isolation inverter is greatly improved.

The invention relates to the technical field of power electronic direct-current converters, in particular to an input and output common-ground high-gain boost converter which comprises a direct-current voltage source Vin, diode components D0-D4, capacitor components C0-C4, a first coupling inductor L1, a second coupling inductor L2, a first mosfet tube S1, a second mosfet tube S2 and a resistor R. The two main loops operate in a staggered mode, so that input current is continuous, input current ripples are small, relatively stable energy is continuously provided for the circuit, the voltage multiplication unit is adopted, the amplification factor of the circuit is increased, the duty ratio of the mosfet tubes S1 and S2 is adjusted, and small current ripples can be kept even under the condition that the boost factor is large. The device has the advantages of high step-up ratio, low device stress, high efficiency, easiness in control and implementation, lower cost and the like, and is suitable for a new energy power generation scene needing high direct current bus voltage grid-connected output under a low input voltage condition.

The present invention aims to provide a vehicle-mounted auxiliary power DC-DC converter, including an input capacitor C1, a Buck converter, a Boost converter, an output capacitor C2, and an LLC resonant converter; the Buck converter and the Boost converter are respectively composed of two branches, and the two branches of the Buck converter are connected in series with the two branches of the Boost converter in a one-to-one correspondence to form two groups of parallel Buck-Boost branch structures; the Buck-Boost branch structure is connected to the vehicle power battery in parallel with the input capacitor C1, and the Buck-Boost branch structure is connected to the input end of the LLC resonant converter in parallel with the output capacitor C2. The present invention also provides an integrated digital control method for a vehicle-mounted auxiliary power DC-DC converter. The converter overcomes the defects of the prior art and has the characteristics of a wide input voltage range, low conduction loss, and low cost.

This invention discloses a phase-shifted full-bridge plasma power supply based on all SiC devices, belonging to the field of special power supply technology. It includes: a rectifier unit with a power factor correction circuit; an inverter unit containing a phase-shifted full-bridge topology composed of SiC power devices and an energy storage inductor, achieving zero-voltage switching through phase-shift control; a transformer unit; an output unit including an output filter capacitor; and a control unit that uses an incremental PID algorithm to generate phase-shift control signals. This invention analyzes the differences in zero-voltage switching between the leading and lagging bridge arms, utilizes the low output capacitance characteristics and dynamic dead-time adjustment of SiC devices, broadens the soft-switching range under light loads, effectively reduces output current ripple, and improves dynamic response speed and overall efficiency.

The present invention discloses a high-stability, low-ripple high-voltage DC converter. The high-voltage DC converter includes a full-bridge inverter circuit, a resonant filter circuit, a transformer, and a voltage doubler rectifier circuit connected in sequence: wherein the voltage doubler rectifier circuit is formed by cascading a plurality of voltage doubler modules; the output ends of a plurality of the voltage doubler modules are connected in series to form a high-voltage DC output; each of the voltage doubler modules is formed by connecting a plurality of voltage doubler units in parallel and output in series and then connecting them in parallel with a bus capacitor; all bus capacitors are connected in series in sequence and then connected to the load. The voltage doubler rectifier circuit in the scheme of the present invention reduces the average current value and voltage variation on the capacitor and reduces the output ripple without increasing the device voltage level; at the same time, it reduces the total output voltage variation when the load changes, reduces the voltage regulation range of the resonant cavity, and improves the output voltage stability.

The application relates to a flyback power supply circuit and a power supply. The flyback primary side circuit comprises a primary side winding connected with a high-voltage power supply. The flyback secondary side circuit comprises a secondary side winding, a switching unit, an energy buffer unit and a charging unit. The switching unit is connected with the secondary side winding. The energy buffer unit is connected with the switching unit, the charging unit and a power supply output end respectively. The charging unit is used for charging the energy buffer unit before the flyback primary side circuit is connected with the high-voltage power supply. The charging unit arranged in the flyback secondary side circuit can charge the energy buffer unit in the flyback secondary side circuit before the flyback power supply circuit is connected with the high-voltage power supply, so that negative voltage of the flyback secondary side circuit is avoided. The application can reduce voltage stress of the switching unit when the flyback secondary side circuit starts, and improve stability and reliability of the flyback power supply circuit.

The invention discloses a voltage regulating circuit and an inverter system, the voltage regulating circuit comprises a first capacitor C1, a voltage dividing branch and a voltage stabilizer D which are connected in parallel between a first node and a second node, a second capacitor C2 and a resistor R0 are connected in parallel between the second node and a third node, and the voltage between the first node and the third node is the total voltage Vs; partial voltage of the total voltage Vs at the first node and the third node is used as driving voltage of the switching tube; a voltage dividing point of the voltage dividing branch is connected to the voltage stabilizer D, and the voltage stabilizer D adjusts the voltage drop of the resistor R0 based on the voltage V2 of the voltage dividing point; the voltage monitoring module is used for monitoring the bus voltage of the inverter system, and when the bus voltage is smaller than a voltage threshold value, the partial voltage of the first node serves as the first driving voltage Vout1; when the bus voltage is larger than the voltage threshold value, the partial voltage of the first node serves as the second driving voltage Vout2, and the first driving voltage Vout1 is larger than the second driving voltage Vout2.

The application discloses a three-level full-bridge dual active bridge converter and a midpoint potential balance control method. The converter comprises a high-frequency transformer, a DC input voltage source is arranged on the primary side of the high-frequency transformer, and series-connected upper and lower capacitors are connected between the positive and negative electrodes of the DC input voltage source. Three-level half-bridge A and three-level half-bridge B are connected in parallel, a node between the upper and lower capacitors is connected to the midpoint of two clamping diodes of the two three-level half-bridges, the center point of the three-level half-bridge A is connected to one end of the primary side of the high-frequency transformer through a power transmission inductor, and the center point of the three-level half-bridge A is connected to the other end of the primary side of the high-frequency transformer through a DC isolation capacitor. In the control method, the primary side power device is divided into a fixed 50% duty ratio basic bridge arm and a non-symmetrical duty ratio adjusting bridge arm, a PI voltage balance loop is constructed by taking the voltage difference of the two capacitors as feedback, the duty ratio of the adjusting bridge arm is dynamically adjusted, the average value of the midpoint current is changed, and the midpoint potential balance is realized.

The utility model discloses a kind of magnetic integrated type secondary side low-voltage side winding circuit, it includes primary side full bridge part, secondary side high-voltage side and secondary side low-voltage side, the secondary side low-voltage side is connected with M9NNMOS pipe, M10NNMOS pipe and M12NNMOS pipe in parallel, the secondary side low-voltage side is accessed primary side full bridge part after a plurality of first resistors and a plurality of capacitors are connected in parallel and then with M11NNMOS pipe series connection.In this application, when the NMOS pipe of secondary side high-voltage side opens, the secondary side low-voltage side M11NNMOS pipe is opened simultaneously to reduce winding floating voltage and reduce the voltage stress of M9 and M10 NMOS.

The present invention discloses a unidirectional multi-string photovoltaic inverter circuit control device and control method, the device includes: a unidirectional multi-string photovoltaic inverter circuit and a switching regulator, wherein the unidirectional multi-string photovoltaic inverter circuit includes a solar cell array component, a high-frequency AC link and a three-phase AC inverter, and the switching regulator is used to control the input circuit switch tube in the solar cell array component according to the input reference current output after the MPPT operation of several solar cell array strings in the solar cell array component, and is used to control the output circuit switch tube in the three-phase AC inverter according to the output reference current of the three-phase AC inverter. The present invention can reduce the voltage stress on the power electronic switch in the inverter circuit, and can improve the conversion efficiency and power density of the photovoltaic system, and can make the solar cell array string work under different operating conditions and realize the isolation of different working modes.

This invention discloses a variable frequency low-voltage stress control system and its control method based on autonomous resonance. The control system includes: a DC voltage source, a primary-side inverter unit, a secondary-side inverter unit, a primary-side resonant branch, a secondary-side resonant branch, a secondary-side rectifier unit, an energy storage branch, a filter capacitor, and a load. The DC voltage source is connected to the primary-side inverter unit; the energy storage branch is connected to the secondary-side inverter unit; the primary-side inverter unit is connected to the secondary-side inverter unit through the primary-side resonant branch; the secondary-side resonant branch is connected to the secondary-side rectifier unit; and the secondary-side rectifier unit is connected in parallel with the filter capacitor and the load. This invention not only reduces the voltage stress on the energy storage capacitor and related power devices, reducing the risk of device damage and extending the system's service life, but also improves the system's energy utilization efficiency without requiring additional energy-consuming absorption circuits, thus possessing significant engineering application value.

A three-level double-buck conversion circuit for a post-stage of an energy storage inverter integrated device, comprising an energy storage battery, a bidirectional DC-DC converter, switching tubes S1, S2, S3, S4, S5, S6, S7, diodes D1, D2, D3, D4, D5, D6, D7, inductors L1 and L2, and capacitors C1 and C2. The three-level double-buck conversion circuit comprises a bidirectional switching tube composed of switching tube S4, diodes D3, D4, D5, and D6, and a double-buck circuit structure composed of switching tubes S2 and S3, diodes D1 and D2, and inductors L1 and L2. The three-level double-buck conversion circuit of the present application organically integrates three-level technology and a double-buck circuit structure, and has the advantages of low switching tube voltage stress, high reliability, and high efficiency.

The application provides an LCC-S type wireless power transmission system parameter optimization method and system, adopts a nested loop optimization structure, firstly performs global scanning on the sending end series inductance value through an outer loop, and finely adjusts the receiving end output current value through an inner loop under each inductance value; based on the system resonance frequency and the coil parameters, the resonance capacitance values are calculated, and then the capacitance voltage and the output power are respectively evaluated under the maximum and minimum coupling coefficient conditions; taking the sending end and receiving end resonance capacitance voltage tending to balance as the core target, the optimal solution is dynamically updated combined with the output power constraint condition, and finally the inductance, capacitance and current parameter combination which makes the capacitance pressure minimum and meets the power transmission requirement is output. Through systematic parameter collaborative optimization, the application effectively reduces the working voltage stress of the resonance capacitance, improves the system safety and engineering applicability, and at the same time ensures the stable and reliable output power in the coupling coefficient change range.

This utility model discloses a clamping absorption circuit and a DC power supply system. The clamping absorption circuit includes a boost switch K1, a buck switch K2, a first clamping absorption branch, and a second clamping absorption branch. The first clamping absorption branch includes a first diode D1, a first capacitor C1, and a first resistor R1. The first diode D1 and the first capacitor C1 are connected in series and then in parallel with the boost switch K1, forming a first node between the first diode D1 and the first capacitor C1. The first resistor R1 is connected between the first node and the positive bus. The second clamping absorption branch includes a second diode D2, a second capacitor C2, and a second resistor R2. The second diode D2 and the second capacitor C2 are connected in series and then in parallel with the buck switch K2, forming a second node between the second diode D2 and the second capacitor C2. The second resistor R2 is connected between the second node and the negative bus.

This invention discloses a series-parallel type switched linear composite envelope tracking power supply, comprising a multilevel converter (VSC), a linear amplifier (VLA), and a switching converter (CSC). The multilevel converter (VSC) and the linear amplifier (VLA) are connected in series, and the switching converter (CSC) and the linear amplifier (VLA) are connected in parallel. The multilevel converter (VSC) tracks the envelope signal and outputs a stepped-wave voltage to fit the load voltage v. o Simultaneously, the stepped waveform voltage output by VSC serves as the input voltage of CSC; the linear amplifier VLA realizes the load voltage v o For the reference signal v ref The switching converter (CSC) outputs current to match the load current. This invention significantly reduces the switching frequency of the CSC and the voltage stress on the switching transistor without increasing the complexity of the series-parallel ET power supply, thereby improving the overall efficiency of the ET power supply.

The application discloses a three-phase E-type hybrid level double-output integrated converter and a carrier PWM modulation method thereof, and belongs to the technical field of power electronic conversion devices. The three-phase E-type hybrid level double-output integrated converter comprises one DC input power supply, two capacitors on the DC input side, 15 switch modules, and one set of three-phase inductive load on each output end of the bridge arm of each phase. The carrier PWM modulation method with added DC offset and zero sequence component is given for the proposed converter. Two sets of modulation waves with added DC offset and zero sequence component are compared with anti-phase stacked carriers respectively. According to the switch state and the comparison result, the logic operation for generating the driving signals of each switch module is derived. One set of DC input voltage is converted into three-level AC voltage on the upper end and two-level AC voltage on the lower end through the inverter circuit, and the frequency and amplitude of the three-phase AC voltage can be adjusted. The three-phase E-type hybrid level double-output integrated converter can be widely applied to the double-motor driving application scene of one master and one slave, and has the advantages of reasonable structure, scientific modulation method, outstanding performance and the like.

The application discloses a modular equalization circuit and a control method thereof. The modular equalization circuit comprises a power supply, a converter, a selection switch, a transformer, a rectifier circuit, a filter and a battery equalization circuit which are connected in sequence. The number of modules is N, the number of energy storage units in each module is M, and the number of the rectifier circuit, the transformer, the filter and the battery equalization circuit is N. The number of the selection switch is N+1. Two output ends of the converter are marked as A and B respectively, i represents the i-th module, when i is odd, the one end of the switch S i is connected with A, the other end of the switch S i is connected with the same name end of the primary side of the transformer T i . When i is even, the one end of the switch S i+1 is connected with B, the other end of the switch S i+1 is connected with the different name end of the primary side of the transformer T i . When i is even, the one end of the switch S i is connected with B, the other end of the switch S i+1 is connected with A. The application significantly shortens the equalization path, improves the equalization efficiency and has strong expansibility.

The invention relates to the technical field of wind power generation and power electronic control, and discloses an energy storage enhanced wind turbine generator system with network construction capability, which comprises a wind energy capturing and converting unit, a direct current bus transmission unit, a network construction type energy storage subsystem and a network construction cooperative control unit, the direct-current bus serves as an energy hub to be connected with the machine-side and grid-side converters, and the energy storage subsystem is connected to the direct-current bus in parallel; a state sensing module, a heat surplus management module and a frequency domain energy distribution module are arranged in the control unit to cooperatively control the converters. According to the invention, the high-frequency instruction is distributed to the energy storage unit through frequency domain energy distribution, and mechanical response hysteresis is solved; a carrier frequency is reconstructed in a transient state by using a dual-mode modulation strategy and an algorithm is switched, so that loss is reduced and thermal runaway is prevented; the active damping and ripple suppression algorithm is combined, transmission chain torsional vibration and direct current voltage ripples are effectively suppressed, the networking stability of the wind turbine generator is improved, and the service life of the wind turbine generator is prolonged.

The utility model discloses a kind of bridgeless voltage doubler PFC circuits, the bridgeless voltage doubler PFC circuit includes power factor inductance, switching unit, drive control module, first and second output capacitor and first, second freewheeling diode;Power factor inductance one end connects alternating current power positive pole, the other end is connected switching unit input end, first freewheeling diode anode respectively, switching unit output end connects alternating current power negative pole;First freewheeling diode cathode connects one end of first output capacitor, the other end of first output capacitor connects second output capacitor, the node of first output capacitor and second output capacitor is connected with alternating current power negative pole;The other end of second output capacitor connects second freewheeling diode anode, second freewheeling diode cathode connects first freewheeling diode anode;Drive control module output end connects switching unit control end, and output control signal controls switching device on-off. The utility model does not need rectifier bridge, converts single-phase voltage into high-voltage direct current, and efficiency is high, cost is low.

The present invention discloses a three-level DC-AC inverter suitable for photovoltaic grid-connected hydrogen production, including: a first transformer and a second transformer, used to convert the direct current outputted by a photovoltaic direct current power supply into alternating current; a clamping circuit, connected to the primary coils of the first transformer and the second transformer, used to clamp the voltage of the primary coils of the first transformer and the second transformer, wherein the primary coils of the first transformer and the second transformer are connected in parallel and respectively connected to the photovoltaic direct current power supply; a three-level conversion circuit, connected to the secondary coils of the first transformer and the second transformer, used to boost and convert the alternating current outputted by the secondary coils of the first transformer and the second transformer into three-level alternating current, wherein the secondary coils of the first transformer and the second transformer are connected in series; and a grid-connected control circuit, used to connect the three-level alternating current outputted by the three-level conversion circuit to the hydrogen production grid. The present invention has high gain and can suppress the generation of leakage current.

The invention discloses a three-phase AC-AC converter and a voltage stress optimization method and equipment thereof, and belongs to the technical field of power converters. The rectifier side of the converter is composed of a three-phase input AC filter, a three-phase rectifier bridge arm, a fly-wheel diode, a DC inductor and a DC capacitor. The inverter side of the converter is composed of a three-phase inverter bridge arm and a three-phase output alternating current filter. According to the voltage stress optimization method of the three-phase AC-AC converter, the voltage stress peak value of the transistor under different parameter conditions is calculated, and the parameter configuration corresponding to the minimum voltage stress value is determined, so that the working parameter with the lowest voltage stress of the transistor is obtained. According to the three-phase AC-AC converter, the voltage stress of the transistor can be effectively reduced, the rated withstand voltage requirement of the device is reduced, the device type selection scheme is optimized, and the operation reliability and the system efficiency of the three-phase AC-AC converter are remarkably improved.

The utility model belongs to the field of inverters, and specifically provides an inverter topological structure and a photovoltaic inverter wherein the inverter topological structure comprises a DC interface, a six-switch single-phase bridge inverter circuit, an LCL filter circuit and an AC interface; the direct current input side of the six-switch single-phase bridge type inverter circuit is electrically connected with the direct current interface; and the inversion output side of the six-switch single-phase bridge type inversion circuit is electrically connected with the AC interface after being filtered by the filter circuit. The LCL filter circuit is arranged to filter the output voltage of the inverter topological structure, the attenuation characteristic of the filter in a high frequency band is effectively improved, meanwhile, the good gain characteristic of a low frequency band is kept, compared with an L-shaped filter, the equipment cost and size are remarkably reduced, the harmonic wave filtering effect is improved, the output voltage is closer to a pure sinusoidal waveform, and the harmonic wave filtering effect is improved. And the generated reactive power is lower, the power loss is smaller, the voltage stress between the switches is reduced, and the service life of the inverter topological structure is prolonged.

The invention relates to the technical field of power equipment, and discloses a multi-level hybrid direct-current circuit breaker control method, system, equipment and medium, which comprises the following steps of: realizing rapid discharge of a capacitor by controlling a switching device of a voltage injection module, injecting a voltage signal opposite to a power supply in polarity into a main branch by utilizing a coupling inductor, and controlling the switching device of the voltage injection module; therefore, rapid forced landing of the fault current is realized. The multi-level modulation of the injection voltage can be realized by utilizing multiple working modes of the voltage injection module based on the flying capacitor structure, and then the fault current is modulated into the ripple current, so that the action window of the mechanical switch is expanded, and the arc-free isolation of the direct current fault is realized.

This application provides an inverter system control circuit, method, inverter system, and electronic device. The control circuit actively switches the operating topology to a three-phase three-wire system by turning off the neutral line switch under grid-connected or off-grid conditions with a balanced load. This allows the inverter to operate with higher DC bus voltage utilization. Under the premise of outputting the same level of AC voltage, the DC bus voltage value can be correspondingly reduced. This means that the upstream photovoltaic boost circuit or battery converter does not need to provide excessively high voltage, thereby reducing the voltage stress on power semiconductor devices, helping to improve overall system efficiency, reduce losses, and potentially reduce heat dissipation requirements. Simultaneously, since the neutral line is isolated, the operating pressure in this mode can be alleviated, or even eliminated in some cases, simplifying control and reducing losses in this part of the circuit.