60 results about "PWM rectifier" patented technology

The invention provides a PWM / Buck cascade circuit auxiliary electrolytic hydrogen production rectification power supply and a control method, and relates to the technical field of electrolytic hydrogen production power supply and intelligent power grids, and the power supply comprises a main power loop and an auxiliary power loop; the main power loop comprises a multi-pulse thyristor rectifier, the power supply side of the multi-pulse thyristor rectifier is connected with an alternating-current power grid, the load side of the multi-pulse thyristor rectifier is connected with one end of a direct-current smoothing reactor, and the other end of the direct-current smoothing reactor is connected with the electrolytic bath; the auxiliary power loop comprises a PWM rectifier and a Buck circuit which are connected in series, the output end of the Buck circuit is connected to the output end of the main power loop in parallel through a direct-current LC filter, the output end of the Buck circuit and the output end of the main power loop are jointly connected into an electrolytic bath for ripple compensation, the multi-pulse rectifier adopts PI control, the PWM rectifier adopts voltage and current double-closed-loop control and SVPWM modulation, Buck adopts PI and feedforward compound control, and the output end of the Buck circuit and the output end of the main power loop are connected in parallel. The system has the advantages of improving the grid-side electric energy quality, the voltage utilization rate, the water electrolysis hydrogen production efficiency and the operation stability.

The application discloses an energy-saving control method of a CSR high-frequency PWM rectifier circuit. According to the value change of each line voltage of three-phase alternating current in a rectifier circuit and the characteristic that the rectifier circuit works at a high frequency, the two pulse wave edges of two phases of the three-phase alternating current are overlapped. The overlapping time of the overlapping of the two pulse wave edges is equal to the sum of the turn-on time and the turn-off time of a switching tube, so that the front edge or the rear edge of a pulse of a switching signal is in a soft switching state or in a cut-off low voltage state, thereby reducing the switching process loss of the switching tube. The application provides the energy-saving control method of the CSR high-frequency PWM rectifier circuit, which can reduce switching loss, reduce cost, save energy, prolong service life and is safe and reliable.

The invention discloses a current source type PWM rectifier control method under a power grid imbalance working condition, and the method comprises the steps: firstly designing a current source type PWM rectifier and a corresponding control system, carrying out the small-signal linearization modeling of the circuit topology of the control system, and building an open-loop transfer function of the control system; secondly, providing a direct current side direct control strategy which does not need a complex phase-locked loop and positive and negative sequence calculation; finally, a modulation strategy for the current source type PWM rectifier is designed, and the modulation performance of the control system is further improved. The novel control method is provided for the current source type PWM rectifier under the unbalanced power grid, compared with a traditional double-closed-loop control strategy, the THD value of the control method is obviously reduced, and the control method has the advantages of being high in power factor, low in input current harmonic wave and the like.

The application provides a non-continuous three-phase rectifier adjustable power decoupling method, and relates to the field of power electronics. The method is characterized in that a capacitor equivalent circuit is connected in parallel to the DC side of a three-phase PWM rectifier, the capacitor equivalent circuit is composed of a first capacitor connected in series with an active negative capacitor circuit, and a digital signal controller is used to sample the relevant voltage and current signals of the AC side and the DC side, and the active negative capacitor capacitance is adjusted by controlling the switching tube, so that the equivalent capacitor circuit can be flexibly adjusted. The application does not require an additional DC power supply, the capacitance and inductance of the passive device used are small, and the volume advantage is significant. The closed-loop control has high precision and equivalent inhibition effect as the traditional large capacitor. The equivalent capacitance is adjusted only by software, the external physical structure does not need to be changed, and the adjustment range is wide. The preset DC side voltage fluctuation amplitude can be calculated and adjusted automatically, different unbalanced working conditions can be adapted, the fluctuation suppression demand can be met, different working modes can be switched according to the AC side working condition, and the application is not continuously operated, so that the switching loss is lower.

The application discloses a parallel power supply current estimation method based on an instantaneous power integration method and relates to the technical field of power electronics and power supply control. The method collects electrical signals on the AC side of a three-phase PWM rectifier in front of each power supply module, calculates the instantaneous power input of the module, and integrates the input power and the voltage on the load side with the switching period of a DC-DC converter in back as an integration window to obtain the single-period energy and voltage integration value, so as to weaken the influence of the energy of energy storage elements such as inductors and capacitors in the circuit on the estimation result, thereby obtaining the preliminary estimation value of the output current of the module. Meanwhile, an independent equivalent loss resistor is introduced for each power supply module to describe the loss in the power supply, and the equivalent loss resistor is estimated in a longer time scale through an offline polling mode, so as to obtain the output current estimation result of each parallel power supply module.

This application provides a control method, system, and electronic device for a PWM rectifier. The control method includes: determining the actual current of the PWM rectifier and determining a current error based on the actual current and a reference current; obtaining a first control parameter based on the current error using a preset algorithm; determining an error compensation value based on the current error using a repetitive controller, and compensating the first control parameter with the error compensation value to obtain a second control parameter; determining the fundamental frequency of the modulation wave based on the second control parameter, and obtaining a control signal based on the fundamental frequency of the modulation wave using a discontinuous pulse width modulation (DPWM) method to control the PWM rectifier. This application introduces a repetitive controller into the discontinuous pulse width modulation (DPWM) method, which improves the problem of large current harmonics caused by periodic errors due to periodic entry into clamping state in the DPWM modulation method, thereby improving control accuracy.

The invention discloses a three-phase voltage type PWM rectifier switch tube open-circuit fault diagnosis method, which comprises the steps of 1, implementing three-layer wavelet decomposition on an input side three-phase current historical database after a three-phase voltage type PWM rectifier power switch tube open-circuit fault by adopting a wavelet decomposition method, extracting a characteristic value corresponding to the switch tube fault and finishing normalization; and 2, performing parameter optimization on the support vector machine through an improved mouse group search algorithm, and determining an optimal penalty factor and a kernel parameter so as to carry out data training and fault diagnosis. The invention aims to analyze the waveform distortion condition of the three-phase current at the input side after the open-circuit fault of the three-phase rectifier switch tube, so as to optimize the fault characteristic quantity and realize the accurate diagnosis of the open-circuit fault of the power switch tube. According to the invention, the fault identification capability of the rectifier system under the abnormal working condition can be effectively improved, so that safe and stable operation of power electronic equipment is ensured.

The invention discloses a 12 pulse wave / PWM hybrid rectifier based on multi-winding phase-shifting transformer power supply and a control method thereof, and relates to the technical field of hydrogen production equipment, and the 12 pulse wave / PWM hybrid rectifier comprises a three-phase AC power grid, a multi-winding phase-shifting transformer, a 12 pulse wave / PWM hybrid rectifier and an electrolytic cell. Wherein the additional winding of the multi-winding phase-shifting transformer adopts a type connection method, and provides a winding internal circulation path of harmonics of three times and multiple times of three; the control method comprises the steps of 12-pulse thyristor rectifier control, PWM rectifier control and DC-DC converter control, and a phase compensation mechanism is introduced for the phase difference generated by the main winding and the additional winding of the multi-winding phase-shifting transformer due to the structure. Through topology integration and an advanced coordination control strategy, the problems that in the prior art, water electrolysis equipment is complex, high in cost, large in harmonic wave and ripple wave, low in power factor, slow in dynamic response and the like are effectively solved.

The invention provides a battery self-checking control method for a bidirectional buck-boost system. The method comprises the steps that a first output signal is calculated based on a battery current reference value, a battery current sampling value and an inductive current sampling value, and the battery current reference value is a discharge current set during battery self-inspection; calculating a second output signal based on the bus voltage reference value, the bus voltage sampling value, the battery voltage sampling value and the battery current reference value; generating a duty ratio of a first driving signal for the charging and discharging circuit based on the first output signal; a duty cycle for a second drive signal of the PWM rectifier is generated based on the second output signal. On the basis of a bus voltage outer ring and a high-frequency inductive current inner ring, a battery current inner ring and a rectifier current inner ring are added, and under the condition of constant current discharge, the bus voltage is controlled together. Therefore, during self-inspection of the battery, the stability of the bus voltage can be maintained while the battery is ensured to be discharged at a constant current.

The invention discloses a method for calculating secondary ripple current of a single-phase PWM (Pulse Width Modulation) rectifier, which comprises the following steps of: A, obtaining input voltage us and input current is of the rectifier through sampling, and respectively obtaining orthogonal components us alpha and us beta of the voltage and orthogonal components is alpha and is beta of the current through orthogonal transformation or delay of a quarter period; respectively calculating a voltage amplitude Us and a current amplitude Is; the included angle between the input voltage and the current is phi, namely a power factor angle; b, the active power P and the reactive power Q of the input power of the rectifier are calculated, and then the power factor angle phi of the grid-side current and the voltage is calculated; obtaining the angular velocity omega of the input voltage by using a phase-locked loop; c, according to the inductance value L, the voltage amplitude Us, the current amplitude Is, the power factor angle phi and the angular velocity omega of the PWM rectifier, the alternating current side secondary pulsation power Pshc of the rectifier is calculated; and D, calculating the secondary ripple current of the DC side of the PWM rectifier in real time by using the PWM DC side given voltage Vdcref and the AC side secondary pulse power Pshc. The method is different from a method for obtaining the reference value of the secondary ripple current on the DC side of the PWM rectifier by adopting current sampling and filtering and the like, and the reference value of the secondary ripple current is directly calculated by directly utilizing the existing parameters of the PWM rectifier; and the precision of the secondary ripple current reference value is further improved on the basis of eliminating a current sensor and a circuit thereof.

The present invention provides a wave energy power generation hydraulic PTO constant speed and pressure control method based on dual parameter joint adjustment, the method comprising: collecting the system oil pressure signal p of the main oil circuit through a pressure transmitter, and sending the oil pressure signal p to the oil pressure closed loop regulation module; measuring the torque signal M of the input shaft of the three-phase permanent magnet synchronous generator through a speed torque meter; g and speed signal n, and the signal M g and n are sent to the oil pressure open-loop regulation module, and the signal n is sent to the oil pressure closed-loop regulation module; the electromagnetic torque of the three-phase permanent magnet synchronous generator is controlled by the three-phase PWM rectifier to indirectly adjust the speed n; the three-phase current signal i at the outlet of the three-phase permanent magnet synchronous generator is collected by the generator vector controller a i b i c , and output SVPWM signal to the three-phase PWM rectifier, while receiving the speed signal n and setting speed n r The present invention has good speed stabilization and pressure stabilization effects.

The application discloses a control method of a diesel-electricity-fuel combined propulsion system, a six-dimensional mathematical model of a six-phase induction motor is established first, then space decoupling transformation is carried out on the mathematical model, a mathematical model of the six-phase induction motor based on a synchronous rotating coordinate system d-q is established, mathematical models of a three-phase voltage type PWM rectifier and a three-phase voltage type PWM inverter are respectively established, and finally, six-phase induction motor double-dq vector control based on SVPWM is carried out; under the motor follow-up power generation condition, the output power of the gas turbine is higher than the total output power of the propulsion system, the redundant power is provided to the motor by the transmission shaft, the motor is driven to generate power, and the requirement of a 10kV level network on harmonics is met.

The application discloses a kind of based on working condition self-adaptive machine tool PWM rectifier energy-saving control method and system, wherein the method comprises the following steps: numerical control system real-time acquisition machine tool operating condition and using operation mode judgment strategy to process and obtain operation mode instruction, operation mode instruction is input to the controller of PWM rectifier, and operation mode instruction includes static rectification mode and PWM rectification mode;The controller of PWM rectifier obtains operation mode instruction and controls PWM rectifier to enter corresponding working mode, when the controller of PWM rectifier obtains static rectification or PWM rectification mode instruction, the controller of PWM rectifier can close or open the high-frequency switching action of PWM rectifier internal power device, so that PWM rectifier only utilizes the diode characteristics of power device or switch and carries out static or normal rectification.The disclosed method can control PWM rectifier to work in different modes according to the operating condition of machine tool, and energy saving can be effectively realized.

The application provides a kind of hybrid vector variable frequency control method based on three-phase rectifier, it is related to power electronic electric energy conversion technical field;Current three-phase PWM rectification technology is important front-stage equipment, and the current of switch tube is large, and the loss of switch tube is composed of turn-on loss and conduction loss, and conduction loss cannot be avoided in high-power state, and switch loss is related to frequency, if switch tube loss is not controlled, switch tube loss will accumulate in the form of heat, when temperature exceeds the limit of switch tube, it often causes irreversible damage to switch tube, therefore, on the basis of considering the power quality of DC side, the action frequency of switch tube of three-phase PWM rectifier is dynamically controlled to realize the continuous operation of three-phase PWM system under high power, and the method considers the stability of DC side voltage and the temperature characteristics of IGBT to carry out frequency modulation.

The invention provides a two-stage hydrogen production power supply device with a self-adaptive virtual impedance adjusting function, which comprises a two-stage converter scheme which is composed of a three-phase voltage source type PWM (Pulse Width Modulation) rectifier and an interleaved Buck circuit and is used for providing direct-current electric energy for an electrolytic bath; the running state detection unit is used for collecting voltage, current and other parameters of the electrolytic cell and judging the running condition; corresponding virtual impedance compensation control is carried out according to the operation condition of the electrolytic cell, and the steady-state characteristic and the dynamic characteristic are improved; and the virtual impedance compensation amount of the power grid voltage is introduced for secondary adjustment so as to reduce the current and voltage fluctuation of the electrolytic cell end and improve the anti-harmonic and anti-voltage fluctuation capability of the system.

The utility model discloses a main and auxiliary integrated power supply system, and specifically relates to the technical field of power supply systems, the main and auxiliary integrated power supply system comprises a main power supply, the main power supply is connected with an auxiliary power supply, the main power supply and the auxiliary power supply are both electrically connected with a master control cabinet, the output end of the master control cabinet is connected with a load through a reversing cabinet, and the auxiliary power supply comprises a circuit breaker. A power grid is connected with a soft start circuit through a circuit breaker, the soft start circuit is connected with an isolation transformer T1 in series, the isolation transformer T1 is connected with an ACDC optimization circuit, and the ACDC optimization circuit is connected with a DCDC staggered step-down chopper circuit. In order to meet the requirements of corresponding speed and output current regulation precision, a high-precision compensation auxiliary power supply is added to an original system. A PWM rectifier principle is adopted, and a power device adopts an IGBT single tube. According to the PWM rectifier, a traditional phase-controlled rectifier is comprehensively improved. The key improvement is that a full-control power switch is used for replacing a half-control power switch, and PWM chopped-control rectification is used for replacing phase-control rectification.

The application provides an electromagnetic damper type self-powered active / semi-active vibration reduction system and a method thereof, comprising a linear-rotation conversion device, an energy conversion device and a load, wherein the linear-rotation conversion device adopts a gear rack or a ball screw; the energy conversion device adopts a permanent magnet synchronous motor; the load is configured as a three-phase voltage type PWM rectifier and a battery; when the system works in an active mode, motor control force is solved by rolling optimization in a model predictive controller according to detected structural displacement, speed, voltage and current feedback information; when the system works in a semi-active mode, analog inertia force, stiffness force and damping force are calculated according to feedback signals, each bridge arm of the three-phase voltage type PWM rectifier is turned on and turned off to realize control of the motor, vibration is suppressed, and the energy of the vibration is recovered to the battery.

This invention discloses a method for diagnosing open-circuit faults in IGBT power devices of a single-phase PWM rectifier based on RVFL. This method obtains the original database of IGBT open-circuit faults based on an experimental platform and its digital simulation system, designs fault feature vectors, trains a fault classifier using an RVFL classifier, adjusts the number of nodes and activation function of the network model to save computational resources and time, and uses the trained network model to classify and identify online acquired data samples. This solves the problem of real-time and rapid diagnosis of IGBT open-circuit faults in single-phase PWM rectifiers and is beneficial for the real-time online operation of fault diagnosis algorithms.

The invention discloses a 3300V mining frequency converter energy feedback system based on a PWM rectifier, and the system comprises an input filtering module which is used for carrying out the filtering of the voltage and current of a power grid side, and obtaining an input voltage and an input current; the rectifying unit is used for rectifying the input voltage and the input current to obtain direct voltage and direct current; the direct-current bus is used for bearing direct-current voltage and current output by the rectification unit and providing stable direct-current power supply support for the inversion unit; the inversion unit is used for converting the direct-current voltage and the direct-current current in the direct-current bus into alternating-current voltage and alternating-current current and outputting the alternating-current voltage and the alternating-current current to a motor; the detection unit is used for detecting voltage and current values of other modules; and the main control unit is used for controlling the rectification module or the inversion module based on the voltage and current values, detected by the detection unit, of other modules, so that efficient utilization of energy is realized, and the stability and safety of rectifier control in a high-voltage scene are improved.

The present invention provides a dual-bus AC / DC hybrid energy routing system and a control method thereof, which relate to the fields of high-power power electronics technology and grid-connected control technology. The system comprises a three-phase PWM bidirectional DC / AC conversion unit, a buck-boost conversion unit 1, a buck-boost conversion unit 2, a bidirectional buck-boost conversion unit, a non-isolated high-gain DC / DC conversion unit, a three-phase PWM rectifier unit, a single-phase PWM inverter unit, a three-phase PWM inverter unit, a full-bridge DAB conversion unit, a full-bridge CLLC bidirectional DC / DC conversion unit, a photovoltaic panel, a diesel generator, a battery, a DC load 1, a DC load 2, a single-phase AC load, a three-phase AC load, a high-voltage side DC bus, a low-voltage side DC bus, and a three-phase AC power grid. The system can be connected to a variety of distributed energy resources and a three-phase AC power grid, providing AC ports and DC ports of different voltage levels for various loads. The system can adjust the operating mode of the energy router according to the generated power of the distributed energy resources and the power of each load, and can perform high-efficiency regulation during grid-connected operation control.

This invention relates to a method for suppressing DC voltage ripple in a high-gain proportional resonant PWM rectifier, belonging to the field of rectifier control technology in power electronics. In existing technologies, when the three-phase voltage and current sampling of a three-phase PWM rectifier is inaccurate, the secondary ripple in the DC bus voltage and the harmonics of the grid-side current cannot be effectively suppressed. The method proposed in this invention establishes a transfer function between the negative-sequence current and the secondary ripple of the DC voltage based on the power conservation relationship between the AC and DC sides. It adjusts the negative-sequence current through negative feedback of the secondary ripple of the DC voltage to achieve voltage ripple suppression. Using the method described in this invention, rapid and accurate suppression of the secondary ripple of the DC voltage and the harmonics of the grid-side current can be achieved, avoiding reliance on mathematical models and complex calculations. It is not affected by sampling errors and inaccurate system parameters, and exhibits better robustness to system parameters and sampling accuracy.

The invention provides a control method and device for a three-phase PWM (Pulse Width Modulation) rectifier, electronic equipment and a storage medium. The control method comprises the following steps of obtaining a line current # imgabs0 # in the three-phase PWM rectifier, and obtaining voltages # imgabs1 # of ac sides of all converters; obtaining a reference voltage vector # imgabs4 # based on the line current # imgabs2 # and the voltage # imgabs3 #, and obtaining flux linkage errors # imgabs7 # of all converters based on the line current # imgabs5 # and the voltage # imgabs6 #; and based on the reference voltage vector # imgabs8 # and the flux linkage error # imgabs9 #, the duty ratios of all converters are adjusted. According to the control method, the three-phase PWM rectifier can be controlled.

The application discloses a high-voltage-reduction-ratio single-stage three-phase current-mode PWM rectifier, which comprises an AC side filter module, a three-phase rectifier bridge module and a DC side switching inductor module which are sequentially connected. p 、 The DC side switching inductor module comprises an inductor L n , an inductor L n , a diode D7 and a diode D8; the anode of the diode D7 is connected with one end of the inductor L n , the other end of the inductor L p is connected to the anode of the diode D8; the cathode of the diode D8 is connected with one end of the inductor L p , the other end of the inductor L p is connected to the cathode of the diode D7, the intersection of the cathode of the diode D7 and the inductor L n and the intersection of the anode of the diode D8 and the inductor L are respectively connected to the two ends of the output side of the three-phase rectifier bridge module. The rectifier utilizes the DC side switching inductor module and the modulation strategy, so that the zero vector state is divided into two parts, the lower output voltage is realized, the high-voltage-reduction ratio is obtained, the influence of the extreme duty cycle of the switching tube on the system performance is effectively reduced, and the stability and reliability of the system are enhanced.

The invention provides a station-level modeling method for large-scale vehicle network interaction, which comprises the following steps: 1) constructing an electromagnetic transient simulation model library in a station-level simulation device for large-scale vehicle network interaction, the electromagnetic transient simulation model library comprising a binary resistance model, an average value model and a constant admittance model; 2) constructing a charging and discharging motor model suitable for the charging and discharging process of the electric vehicle, wherein the charging and discharging motor model is formed based on a three-phase voltage type PWM rectifier and a bidirectional DC / DC converter; 3) based on the electromagnetic transient simulation model library and the charging and discharging machine model, establishing a large-scale vehicle-network interaction station-level digital simulation system, constructing a large-scale vehicle-network interaction station-level model, and connecting all charging piles in parallel to a power grid node by adopting a common alternating current bus framework to realize simulation of a dynamic interaction process in a large-scale electric vehicle grid-connected scene; the problem that an existing vehicle network interactive simulation model cannot accurately simulate electrical coupling and impedance interaction generated during parallel operation of multiple charging piles under a station-level scale is solved.

The application provides a network-constructed V2G intelligent charging and discharging method, device, system and storage medium, relates to the technical field of data processing, and the method comprises the following steps: detecting the voltage and current information of the power grid and the coupling point of the device through the signal acquisition unit of the network-constructed V2G charging and discharging device, and determining the operation condition of the power grid; based on the operation condition of the power grid, the model prediction control algorithm is used to optimize the charging and discharging strategy, the target of supporting the voltage / frequency of the power grid is given priority to under the weak power grid condition, and the target of maximizing the charging and discharging benefit is given priority to under the normal condition; according to the optimized charging and discharging strategy, the working mode of the three-phase voltage type PWM rectifier and the bidirectional DC / DC converter in the main circuit is controlled, and the rectification or inversion state is switched; in the charging and discharging process, the active power and the reactive power are independently adjusted, the voltage / frequency support and the reactive power compensation of the power grid are realized; the state of charge of the electric vehicle battery and the operation state of the device are monitored in real time, and are fed back to the control unit.

The present invention provides a dual-multiplexed, full-operating-condition topology self-switching, island-supported energy router, relating to the field of power electronics technology. The router includes a three-phase PWM rectifier unit, a three-phase PWM inverter unit, a bidirectional DC / DC converter unit, a first bidirectional buck-boost converter unit, a second bidirectional buck-boost converter unit, and a third bidirectional buck-boost converter unit. The ports of the dual-multiplexed, full-operating-condition topology self-switching island-supported energy router are respectively connected to a generator, a photovoltaic panel, a battery pack, a supercapacitor, an AC load, and a DC load. The router adjusts the operating mode of the energy router according to the remaining capacity of the battery pack connected to the external port, performs charging and discharging operations by determining the remaining capacity of the battery pack, and can dynamically adjust the remaining capacity between the batteries within the battery pack. The energy router can also control the output voltage of the photovoltaic panel connected to the external port by multiplexing the three-phase PWM rectifier unit, so that the photovoltaic panel always maintains the maximum operating voltage.

The application discloses a three-level PWM rectifier fast modulation and neutral point potential balance control method, which comprises the following steps: 1) according to a mathematical model of the three-level PWM rectifier, a modulation model of the three-level PWM rectifier is established based on the mathematical model and constraint conditions of duty ratios of nine switch tubes; 2) a basic solution system and a special solution of a linear equation set are utilized to decompose free components of a modulation process, and different modulation strategies are obtained by appropriately selecting different free components; and 3) a control strategy that AC components of duty ratios of three zero potential switches should be in-phase with three-phase currents is proposed, and solving of an inequality with four degrees of freedom is reduced to one, and finally a value range of one degree of freedom is determined. According to the inequality constraint, the modulation result is solved, and the calculation workload is small and the speed is fast; the proposed neutral point balance control strategy reduces the duty ratio fluctuation range of the three zero position switches, thereby providing a larger space for voltage or current control of the three-level PWM rectifier.

The invention discloses a fractional order PI controller parameter setting method and device, a storage medium and a terminal, and the method comprises the steps: obtaining a plurality of groups of initial parameters used for controlling a PWM rectifier in a PI controller, the initial parameters comprising an integral order, a proportionality coefficient and an integral coefficient; setting the initial parameters by utilizing a water circulation algorithm, taking a plurality of groups of initial parameters as initial raindrops of the water circulation algorithm, and classifying the initial raindrops to obtain a stream population, a river population and a sea population; iteration is at least carried out on the initial raindrops, iteration is stopped until the preset number of iterations is reached, and a sea population is output; through multiple rounds of iteration, raindrops flow among the populations, new raindrops are generated for the populations meeting the evaporation conditions, the positions of the new raindrops are updated through rainfall, and finally the sea populations are output; and controlling the PWM rectifier through a fractional order PI controller based on the parameters corresponding to the sea population obtained by the last iteration. According to the invention, the control precision and the dynamic performance of the PWM rectifier are obviously improved.

This invention discloses a high-power superconducting magnet power supply system and control method with controllable positive and negative rates. The system includes an input stage, an intermediate stage, and an output stage. The input stage is a three-phase full-bridge voltage-type PWM rectifier circuit, connected to a three-phase power grid. The intermediate stage is a modular DAB converter composed of three cascaded dual active bridges, connected to the input and output stages. The output stage is an H-bridge structure, connected to the high-power superconducting magnet. By controlling the power switches in individual DAB and H-bridge circuits using PWM, the high-power superconducting magnet can be magnetized and demagnetized at controllable rates. This power supply system consists of three stages: an input stage, an intermediate stage, and an output stage. The control method, combined with the circuit topology, is simple, efficient, and easy to implement. It effectively controls the charging and discharging rate of the high-power superconducting magnet and feeds electrical energy back to the power grid during discharge.

The invention discloses a current source type PWM rectifier control method, and relates to the field of rectifier control. The method comprises the following steps: firstly, carrying out small-signal linearization modeling on a circuit topology of a current source type PWM rectifier control system, and establishing an open-loop transfer function of the system before and after active damping is added; secondly, damping parameters are designed through active damping, and the influence of series resonance of the output LC filter is restrained; on the basis, a switching loss optimization modulation strategy is designed, and the modulation performance of the system is further improved; and finally, setting a voltage and current double-closed-loop controller, determining controller parameters of a current inner loop and a voltage outer loop, and realizing optimization of the control performance of the current source type PWM rectifier control system. The control method is provided for the current source type PWM rectifier, and the current source type PWM rectifier has the advantages of being good in tracking performance, dynamic response speed and operation stability, high in power factor, low in input current harmonic wave and the like.