71results about How to "Harmonic reduction" patented technology

The invention relates to the technical field of power grid impedance simulation control, and discloses a new energy grid-connected detection platform power grid impedance simulation control method which is based on a new energy grid-connected detection platform. Comprising the steps of output voltage and current sampling, phase voltage calculation, coordinate transformation, voltage regulation, modulation wave calculation, static coordinate system conversion, voltage calculation under simulation power grid impedance, SVPWM modulation and the like. According to the method, through accurate calculation and adjustment of each step, high-precision grid-connected performance evaluation can be realized, and reliable operation of new energy equipment under different conditions is ensured; performance testing can be carried out on different types of new energy equipment, by optimizing voltage regulation and SVPWM modulation, improvement of electric energy quality, reduction of harmonic waves and voltage fluctuation and guarantee of stability and high efficiency of a power system are facilitated, power grid impedance is simulated in a wide frequency domain, and engineering implementation is easy.

The invention discloses a vehicle-mounted bidirectional power converter which comprises a pre-stage voltage stabilization module, a pre-stage driving circuit, a post-stage driving circuit, a post-stage filtering module and an electric vehicle battery module, the pre-stage voltage stabilization module is used for balancing circuit voltage and supporting reactive power, the pre-stage driving circuit is of a single-phase full-bridge AD-DC topological structure, and the post-stage filtering module is of a single-phase full-bridge AD-DC topological structure. The front-stage driving circuit is of a half-bridge type bidirectional DC-DC topological structure, the rear-stage driving circuit is of a half-bridge type bidirectional DC-DC topological structure, the front-stage driving circuit and the rear-stage driving circuit are connected together through a direct-current voltage-stabilizing bus, the size is small, the weight is light, a front stage and a rear stage do not interfere with each other, control is easy, the rear-stage filtering module is used for restraining direct-current side second harmonics, the harmonic quantity is prevented from influencing the stability of output direct-current voltage, and the output direct-current voltage is stable. According to the converter, a corresponding control method is designed, non-inductive decoupling control and a single-phase phase-locked loop of an improved loop filter are adopted, the phase of a power grid is accurately and efficiently obtained, and the converter works stably.

The invention discloses a harmonic suppression predictive control method and module for a three-phase grid-connected inverter system, and belongs to the field of power electronic control. The method comprises the following steps: firstly, establishing a continuous domain state space model of a three-phase grid-connected inverter system under a dq coordinate system, discretizing the state space model at a k moment, and obtaining a prediction model of a k + 1 sampling power grid current; enabling the power grid current prediction model to reach a power grid current reference value at a k + 1 sampling moment, and calculating a reference inverter voltage control reference value; calculating a voltage control reference value of the inverter integrated with harmonic suppression by combining the voltage control reference value of the reference inverter and the discretized quasi-resonance controller; determining an optimal voltage vector and action time of an inverter voltage control reference value capable of synthesizing the integrated harmonic suppression; and generating a control pulse signal and applying the control pulse signal to a switching tube of the three-phase grid-connected inverter to realize harmonic suppression prediction control of the three-phase grid-connected inverter system. The steps are simple, and the harmonic prediction and suppression control effect is good.

The invention relates to an equivalent two-level fast double-vector model predictive control method applied to a three-level inverter. The method specifically comprises the following steps: sampling output current and direct current side upper and lower capacitor voltages at a k moment; predicting an expected voltage according to the mathematical model of the three-level inverter and the expected current; performing first value function calculation according to an equivalent two-level vector set composed of positive and negative small vectors to obtain an optimal small vector; calculating a second value function according to the equivalent two-level vector set where the optimal small vector is located to obtain a suboptimal vector; according to the characteristic that the vector action time is inversely proportional to a value function, the action time of an optimal small vector and the action time of a suboptimal vector are calculated; and applying a switching signal under the combined action of the optimal small vector and the suboptimal vector to a three-level inverter. According to the method, the vector set equivalent to two levels is established, so that the vector optimization process is simplified, and the model calculation time is greatly shortened; a value function of a single control target is established, and the tedious design process of weight factors is omitted; and a double-vector model predictive control method is adopted, so that output current harmonics are reduced.

The invention provides a novel high-power low-ripple-output hydrogen production converter and a control method. The novel high-power low-ripple-output hydrogen production converter comprises a six-pulse conversion unit, a filter circuit and a three-phase stacked interleaved Buck circuit. The six-pulse commutation unit is connected in series with the filter circuit, then is connected in series with the three-phase stacked interleaved parallel Buck circuit 3, and finally is connected with a load. And the direct-current voltage of the converter is changed by controlling the phase of the trigger pulse of the thyristor valve so as to realize six-pulse direct-current power transmission. The main branch of the three-phase stacked interleaved parallel auxiliary branch is used for realizing power transmission, and the auxiliary branch is used for eliminating output current ripples. A voltage-current double closed-loop control strategy can ensure that each phase of the main branch realizes a good current sharing effect; alternating current component complementation and ripple complementation of the current IAX and the current IdcMain can be achieved by controlling the auxiliary branch switching tubes SAX1 and SAX2, then zero ripple of the output current Idco of the converter is achieved, and control over the auxiliary branch is completed. According to the invention, high-power low-current ripple output can be realized in a low-voltage high-current scene.

The embodiment of the present application provides a motor and a stator thereof and an electric device. The stator includes a stator core and a stator winding arranged on the stator core, the inner wall of the stator core is provided with a plurality of winding slots, and the stator winding includes a conductor inserted in the plurality of winding slots. The stator winding includes a plurality of phase windings, and each phase winding includes a first branch and a second branch.

The invention provides a dead zone compensation method, device and equipment of an energy storage converter, a medium and a product, and relates to the technical field of energy storage systems. According to the method, the interval of each phase of current is determined according to the three-phase output current acquired by the current sensor, and the basic dead zone compensation amount is dynamically calculated by combining the preset linear function, so that the problem of overcompensation or undercompensation caused by the fact that the existing fixed compensation amount method does not consider the compensation demand difference of different current magnitudes is avoided; the compensation direction is determined by obtaining the instantaneous value of each phase of modulation wave so as to obtain the target dead zone compensation amount, and accurate matching of the compensation direction and the expected output voltage direction is ensured; and the target dead-zone compensation amount and the original modulation wave are superposed to generate a corrected modulation wave, and then a pulse width modulation signal driven by a switching tube is generated, so that the pulse width modulation waveform difference caused by dead-zone time can be effectively counteracted, the output current harmonic wave of the energy storage converter is reduced, and the energy storage efficiency is improved. And stable and reliable operation of the energy storage converter and the whole energy storage system is ensured.

The invention relates to a frequency conversion cooperative starting control method for a motor of a ship emergency power system. The method comprises the following steps: step 1, modeling of the ship emergency power system: establishing an optimal configuration model of a ship comprehensive power system based on multiple constraint conditions of operation economy, system operation safety and power distribution rapidity of a diesel generating set; step 2, load starting conditions of the high-power motor: when the number of pole pairs of a motor winding is fixed, the starting torque of the motor can be adjusted by changing the terminal voltage and the power supply frequency; and 3, AFE control is adopted for a rectification part, and V / F control is adopted for an induction motor. The problem that an existing motor starting control method is not suitable for a ship emergency electric power system and cannot meet the requirement of a high power factor is solved, the alternating voltage generated by the AFE can still be kept in a stable state, the frequency conversion control mode is more stable, and the reliability is higher. The method is more suitable for stabilizing the condition of high ship pulse load power change, and the stability of a ship emergency power system is further improved.

The present invention discloses a high-efficiency, low-harmonic, bidirectional elevator energy recovery converter with a self-stabilizing function, which belongs to the field of power electronics technology. The main circuit of the bidirectional elevator energy recovery converter of the present invention includes a voltage stabilizing circuit, a bidirectional elevator energy recovery converter circuit and an AC side midpoint generating circuit; the voltage stabilizing circuit can ensure the voltage balance of the DC bus capacitor, so that the converter has a self-stabilizing function; the bidirectional elevator energy recovery converter circuit is used for electric energy recovery of the elevator system, and can recover the regenerative energy generated by the motor and feed it back to the power grid or storage device during the elevator up and down process; the elevator energy recovery converter proposed by the present invention can realize the bidirectional flow of energy and achieve the purpose of energy saving; and it adopts a multi-level topology, with a large number of output voltage levels, which can effectively reduce the output current harmonics and effectively reduce the impact on the power grid.

The utility model relates to the technical field of electric energy management, and provides a power-saving protection device adopting a three-dimensional structure machine core, which comprises a machine core, a machine case, a loop assembly and a control system, the machine core is arranged at the bottom of the machine case, the machine core is connected with the control system through the loop assembly, the machine core comprises an iron core group and a high-low coil winding, and the iron core group is connected with the high-low coil winding through the loop assembly. The iron core set is an equilateral triangle three-dimensional coil iron core, the height coil windings are located at the vertex angles of the equilateral triangle three-dimensional coil iron core, and the three height coil windings are arranged at the same distance and distributed in an equilateral triangle mode. According to the intelligent power-saving protection device, the magnetic field among the three machine cores is adjusted in real time through the control system, the unbalance phenomenon of three-phase current is solved, higher harmonics are reduced, pollution such as surge transient is restrained, energy is saved, and meanwhile the service life of load equipment is prolonged.

The present invention relates to a simplified vector fixed-frequency predictive current control method for a grid-connected inverter, comprising the following steps: step S1: calculating a current prediction value according to a current state parameter of a system, and calculating a predicted current difference; step S2: determining two groups of voltage vector combinations that need to be traversed by judging the sector where the predicted current difference is located; step S3: calculating the action time of each voltage vector in step S2, substituting it into a cost function for traversal optimization, and obtaining an optimal voltage vector combination; step S4: inputting the optimal voltage vector combination and action time into a DPWM1 modulator to obtain a pulse signal to control the inverter, and obtaining a pulse signal. The present invention effectively reduces harmonics. By calculating and compensating for the predicted current error, three voltage vectors are used to act on the grid-connected inverter in each control cycle, so that the current ripple is significantly reduced and the current control accuracy is improved.

The application discloses a random rotation DEM structure for reducing switch activity, comprising a digital-to-analog converter, a digital input of the digital-to-analog converter is divided into an input code and a random rotation number, the random rotation number is input into a switch activity reduction structure through a barrel shifter output result delayed by a D flip-flop for one period, a feedback output of the switch activity reduction structure is fed back to the barrel shifter as an input, and an output of the barrel shifter after rotation controls corresponding switches and is connected to a corresponding cell array. The application uses input data to replace a pseudo-random number generator, and uses relatively simple logic to realize a switch activity reduction function, so that the complexity is reduced.

The present invention discloses an AC output circuit control method for testing the breaking capacity of a circuit breaker. The AC output circuit is composed of a supercapacitor, a single-phase inverter and a multi-magnetic circuit transformer. Considering the influence of factors such as transformer leakage inductance on current control, a double closed-loop control method combining the primary current model predictive control of the multi-magnetic circuit transformer and the secondary current PI effective value control is adopted. The system error is observed and compensated in the model predictive control by a state observer. In order to achieve a good control effect of the model predictive control, an online parameter identification method is used to establish a more accurate system model, and a dead time compensation method is used to reduce system harmonics. The control method has stable output current and small current harmonics, which provides an important means for realizing AC output of a single-phase inverter.

The invention discloses a resonance elimination equipment control method and device and a nonvolatile storage medium. Relates to the technical field of power system control. The method comprises the steps that after n charging piles are connected to a target node of a power grid, the target node is connected to resonance elimination equipment, and the harmonic current and the harmonic voltage of the target node after the target node is connected to the resonance elimination equipment are detected, and the resonance elimination equipment comprises an active power filter; and based on the harmonic current and the harmonic voltage, whether a harmonic elimination strategy of the harmonic elimination equipment is adjusted is evaluated, and the harmonic elimination strategy is used for representing a strategy for controlling harmonic waves generated by the target node. The technical problem that the power supply quality of the charging pile is affected due to the fact that a large number of harmonic waves exist in the charging process of the charging pile for the electric vehicle in the related technology is solved.

The invention discloses a wide-speed-regulation strong-overload staggered double-V-shaped variable reluctance permanent magnet flat wire motor and a control method thereof, a rotor is composed of two pairs of V-shaped permanent magnet structures, namely a large V-shaped permanent magnet structure and a small V-shaped permanent magnet structure; the large V-shaped permanent magnet structures are symmetrically arranged; the small V-shaped permanent magnet structures are asymmetrically arranged; the ends of the large V-shaped permanent magnet structures are slotted, and the bottoms of the large V-shaped permanent magnet structures are connected to form an arc-shaped magnetic barrier. According to the small V-shaped permanent magnet structure, the end of a right small permanent magnet is slotted, an elliptical magnetic barrier is arranged between a left small permanent magnet and a left large permanent magnet, meanwhile, a stator of the permanent magnet motor is provided with a double-layer flat wire winding structure, and two sets of windings adopt two inverters to achieve time division multiplexing control. Various winding motor working conditions and functions correspond to different inverter driving control modes. Compared with an existing built-in V-shaped permanent magnet motor, the motor has the advantages that the overload performance and weak magnetic performance of the motor are improved, and the requirements of high efficiency and high power density of the motor under variable operation conditions are met.

The invention discloses a current source inverter high-speed permanent magnet synchronous motor control method and system based on LADRC, and the system part comprises a position estimation module, a rotating speed regulator, a current sensor, a voltage sensor, a coordinate transformation matrix, a current regulator, a current generation module and a space vector pulse width modulation module. According to the control method, a second-order LADRC current regulator is designed to calculate a current reference value of the inverter, d-q axis decoupling is realized in the regulator, the dynamic performance of the current source inverter is improved, current harmonics are effectively reduced, and the anti-interference capability and robustness of the system are improved. According to the method, the problem of system instability caused by high control order and serious coupling of the motor under the high-speed working condition can be solved, the robustness and dynamic performance of the system are improved, the problems of high cost and low reliability of a traditional position sensor during high-speed operation are solved, the hardware cost of the system is reduced, and the response speed is increased. The invention relates to a motor control technology.

Boost three-bridge-arm inverter and boost regulation method. Usually, in a 380V system, the withstand voltage of the power tube is generally above 800V, the lower tube of the full-bridge inverter circuit often generates serious heat, and the harmonic content in the power grid is also very high. The present invention comprises a power supply device module (101), the power supply device module is connected to a push-pull boost module (102), the push-pull boost module is connected to a rectifier filter module (103), the rectifier filter module is connected to a three-bridge-arm inverter bridge module (104), and the three-bridge-arm inverter bridge module is connected to an LCL filter module (105); the power supply device module, the push-pull boost module, and the LCL filter module respectively output signals to the A / D conversion end of the DSP main controller (108), and the PWM output port of the DSP main controller is respectively connected to an isolation drive module A (107) and an isolation drive module B (111). The present invention is applied to a boost three-bridge-arm inverter.

The embodiment of the present invention discloses a hybrid multi-level bidirectional split-phase inverter, including a bidirectional inverter circuit and a controller. The bidirectional inverter circuit includes DC, two groups of AC, two DC filter capacitors, two AC filter inductors, two groups of AC filter capacitors, two vertical bridge arms and two horizontal bridge arms. The vertical bridge arm is composed of two power switch tubes connected in series, and the horizontal bridge arm is composed of two power switch tubes connected back to back in series. The controller collects AC and DC side voltage and current signals, flexibly switches between several modes, and stabilizes the output voltage or current. The output voltage of the present invention is five-level in dual live wire mode or single-phase power system, and the output voltage is three-level in single live wire or dual live wire parallel mode. The output equivalent frequency of the present invention is several times the switching frequency, thereby improving the inverter conversion efficiency, reducing the output voltage or current harmonics, and reducing the volume of the filter inductor, so it has a high industrial application value.

The present application relates to a kind of functionization outer diameter unequal thickness magnetic ring and its magnetizing method, belong to permanent magnet motor technical field, the inner diameter of unequal thickness magnetic ring is circular, and the outer diameter is change curve, wherein, the change curve of outer diameter is constant in main magnetic pole portion thickness, and the thickness is reduced in the transition position between adjacent main magnetic pole portion;The unequal thickness magnetic ring adopts bonded neodymium iron boron material.The present application is composed of a functionization outer diameter bonded neodymium iron boron magnetic ring and its matching multipole magnetizing fixture, wherein the outer diameter of magnetic ring adopts two kinds of functionization size, by reducing the thickness of magnetic pole transition area, the harmonic component of surface magnetism of magnetic ring is controlled, and the amplitude of cogging torque is reduced.The multipole magnetizing core of matching magnetizing fixture can magnetize magnetic ring into surface alternately distributed multiple magnetic poles.

The application belongs to the technical field of electronic power, and particularly relates to a multi-target hybrid modulation method, system and device of a T-type three-level inverter. The method firstly judges whether the inverter is operated at an extremely low modulation degree; if yes, the theoretical midpoint currents of DPWM1 and DPWM3 modes are calculated in parallel, and the extended midpoint currents corresponding to four hybrid modulation modes generated after the introduction of VSVPWM sequences in the two modes are calculated; then, according to the numerical relationship between the real-time calculated midpoint compensation current and the midpoint currents, the optimal hybrid modulation mode is dynamically selected or the basic DPWM mode is returned to; finally, three-phase double modulation waves are generated, and PWM signals for driving all power switches are output after carrier comparison. The application realizes multi-target optimization of the midpoint potential, switching loss and output waveform under extreme working conditions, and significantly improves the system stability and performance.

The present invention provides a high rotor magnetic concentration structure, a rotor, a motor and a compressor, which relate to the technical field of motor technology and solve the technical problem that the utilization rate of magnetic steel is not high when the energy efficiency of the motor is improved. The high rotor magnetic concentration structure includes a structural body located at the end of the rotor and arranged perpendicular to the rotor d axis, and the structural body is made of a material with an axial magnetic resistance less than that of the laminated silicon steel sheet; the structural body includes a first core body and a second core body respectively located on both sides of part or all of the magnetic steel; the outer side of the first core body is an arc-shaped structure, and its arc outer diameter corresponding to the rotor d axis position is not greater than the arc outer diameter corresponding to the rotor q axis position; the rotor includes a magnetic concentration structure, and the magnetic concentration structure is located at the part of the rotor that is higher than the stator core; the motor includes the above-mentioned rotor; the compressor includes the above-mentioned motor. The present invention is used to provide a high rotor magnetic concentration structure that can achieve a high magnetic concentration effect, increase the utilization rate of magnetic steel, reduce circuit copper loss, and achieve the effect of improving the efficiency of the motor.

The application provides a motor stator assembly and a motor, and belongs to the field of motor design.The motor stator assembly comprises a stator core, the stator core comprises a yoke ring and a plurality of stator teeth, adjacent stator teeth form stator slots, and the motor stator assembly further comprises a stator slot spacing assembly, the stator slot spacing assembly comprises a plurality of magnetic conductive strips, each magnetic conductive strip is located in a slot opening of a stator slot, and a gap is formed between the magnetic conductive strip and the adjacent stator teeth.The application sets one magnetic conductive strip in the slot opening of each stator slot, thereby increasing the number of stator slot slots to twice the original number, greatly reducing the cogging torque and harmonics under the operating condition of the motor, greatly reducing the actual slot width of the stator slot, and optimizing the noise and vibration during the operation of the motor.Different from the traditional subtractive method for reducing the cogging harmonics, the application increases the number of stator teeth in a single period by additive manufacturing to reduce the cogging harmonics, and has the advantage of not damaging the magnetic flux path of the stator teeth.

The invention discloses a rotor punching sheet and a permanent magnet motor thereof, the rotor punching sheet comprises a sheet body and even number of synthetic magnetic poles, and the even number of synthetic magnetic poles are distributed on the sheet body along the circumferential direction; an arc corresponding to the outline of the outer circle of each combined magnetic pole and the shaft hole of the sheet body are eccentric, and a first notch and a second notch which are concave inwards are formed in the two ends of the arc respectively and are symmetrical about the midpoint of the arc. The arcs of the outer circle outlines of the combined magnetic poles are eccentric to the rotor shaft hole, and each arc is provided with the first notches and the second notches which are symmetrically distributed, so that uneven air gap distribution which is in a specific shape and is in a certain regular size is formed, which is equivalent to that very ingenious pole cutting treatment is performed on the rotor; the sine degree of air gap flux density can be optimized, the effects of weakening harmonic waves of all orders and reducing cogging torque are achieved, and vibration and electromagnetic noise are reduced while the efficiency of the motor is improved.

A total of effective values of integer-order components of second to 40th orders in a total current (i _total) which is obtained by adding up an indoor-unit input current (iin_indoor unit) and an outdoor-unit input current (iin_outdoor unit) and which flows through a first power line (L1) is less than a sum of a total of effective values of integer-order components of the second to 40th orders included in the indoor-unit input current (iin_indoor unit) that flows through a second power line (L2) and a total of effective values of integer-order components of the second to 40th orders included in the outdoor-unit input current (iin_outdoor unit) that flows through a third power line (L3).

The invention relates to a driving control method and device of a silicon controlled rectifier circuit, electronic equipment and a storage medium. The method comprises the following steps: acquiring an input voltage parameter of the silicon controlled rectifier circuit; determining a generation window of a driving pulse based on the input voltage parameter, wherein the generation window of the driving pulse comprises a zero crossing point of an alternating current signal; acquiring a driving control condition of a generation window of the driving pulse according to a voltage modulation parameter; and on or off driving control is carried out on the silicon controlled rectifier circuit based on the driving control condition. According to the embodiment of the invention, the driving control condition of the generation window of the driving pulse is obtained according to the voltage modulation parameter, and generation of resonance waves and noise can be reduced.

An electrical charging apparatus (10) working to electrically charge an electrical storage device (110) includes an electrical power converter (13, 20, 30) and a controller (70). The electrical power converter converts an alternating-current input voltage into a direct-current voltage and outputs it to the electrical storage device. The controller works to control the electrical power converter to pulsate the charging current supplied from the electrical power converter to the electrical storage device. The controller also controls the electrical power converter to set a pulsation frequency of the charging current to an integral multiple of the frequency of the input voltage and also to bring a phase difference between a zero-crossing time of the input voltage and a time when the charging current is minimized to be smaller than or equal to one-eighth of one cycle of the input voltage.

The invention discloses a three-phase three-level ANPC series resonant dual active bridge DC / DC converter, belonging to the field of DC / DC converters, comprising: a control unit, a three-phase transformer, and two three-phase hybrid power device ANPC three-level circuits respectively connected to two sides of the three-phase transformer, a three-phase resonant network is connected between the primary side of the three-phase transformer and the three-phase hybrid power device ANPC three-level circuit connected thereto; the control unit is used to control the on and off of each switch tube in the three-phase hybrid power device ANPC three-level circuit, so that the neutral point level of the three-phase transformer is V dc / 6, 0 or V dc / 6, the voltage at the output of each half-bridge ANPC three-level bridge arm relative to the connection point of the two DC voltage-dividing capacitors is ‑2V dc / 3, ‑V dc / 2, ‑V dc / 3, 0, V dc / 3, V dc / 2 or 2V dc / 3, the resonant tank voltage of each phase is an eleven-level voltage. A three-phase three-level ANPC active bridge is designed in the DC / DC converter, so that the resonant tank voltage waveform is a multi-level voltage step wave that is closer to a sine wave, thereby reducing the reactive loss of the converter and the current stress borne by the switch tube.

The utility model provides a direct-current step-down power supply circuit and an energy storage air conditioner. The direct-current step-down power supply circuit is used for an energy storage air conditioner and comprises a step-down conversion module which is connected with direct current through the input end of the step-down conversion module and carries out voltage conversion on the direct current; the enabling module comprises a first resistor and a second resistor, the first end of the first resistor is connected with the enabling end of the step-down conversion module, the first end of the second resistor is grounded, and the second end of the first resistor and the second end of the second resistor are jointly connected to the enabling end of the power supply chip; the first resistor and the second resistor are used for calculating the range of the input voltage of the step-down conversion module so as to drive the step-down conversion module to work according to the input voltage of the step-down conversion module; and the output processing module is used for filtering high-frequency noise and harmonic waves in the voltage of the output end of the step-down conversion module. According to the circuit, through the enabling module, the step-down conversion module can be effectively protected according to the input voltage range, and the requirement of an energy storage air conditioner can be met.

The invention discloses an odd-layer flat wire motor stator and winding structure, which comprises a stator iron core, the stator iron core is formed by laminating a plurality of silicon steel sheets, a plurality of rectangular grooves with the same size are formed in the stator iron core according to a circumferential array, and a plurality of conductors are inserted into the plurality of rectangular grooves. Taking 54-slot five-layer coils as an example, the invention introduces an odd number H-pin winding patent of coils 5, 7 and the like of each layer of the winding, a stator adopts an arrangement mode of the odd number of the coils and a composite distribution winding arrangement mode, so that magnetomotive forces generated by the coils of all phases have phase differences, all the magnetomotive forces are mutually superposed, and the winding structure is formed. The superposed magnetomotive force is smaller than the superposed magnetomotive force in the prior art, so that the motor can weaken harmonic waves generated by the motor to a certain extent, especially can greatly weaken fifth harmonic waves and seventh harmonic waves, can reduce torque pulsation and noise, and can improve the performance of the motor.

The invention discloses a three-phase water pump speed control cabinet based on the DMX512 protocol, which includes: a DMX512 console, the DMX512 console is used to send a DMX512 control signal; a DMX512 signal decoder, the output channel of the DMX512 console is connected to the DMX512 signal input end of the DMX512 signal decoder, and the DMX512 signal decoder is used to decode the DMX512 control signal; a balancing module, the balancing module is used to balance the decoded signal output by the DMX512 signal decoder, so that the signal synchronization between each three-phase thyristor voltage regulating module is improved and the signal strength difference is reduced, so that each water pump motor correspondingly controlled by each three-phase thyristor voltage regulating module is in a synchronous state, and the three-phase water pump speed control cabinet based on the DMX512 protocol in the invention saves the frequency converter, thereby reducing harmonics, and also prevents the cable output by the frequency converter from generating great signal interference due to high-frequency power changes. The layout of electrical facilities is simplified, and no isolation transformer is required, so that safety is improved.