17results about How to "Reduce harmonic content" patented technology

The invention discloses a compound control method for improving the current control performance of a three-phase LCL type grid-connected inverter. The method comprises the following steps: establishing a system loop gain based on digital control delay; composite control is realized by adopting a mode of combining a capacitance current sampling modification mode and a delay compensation link, and the capacitance current sampling modification mode is used for shortening capacitance current sampling delay and comprises the steps of sampling grid-connected current at a wave trough of a triangular carrier wave, sampling capacitance current at a wave crest of the triangular carrier wave, and carrying out delay compensation on the grid-connected current. A modulation signal is loaded at the next grid-connected current sampling moment, and capacitance current sampling delay is shortened by half beat; the delay compensation link is used for compensating the influence of digital control delay, the influence of digital control delay is reduced by embedding a lead phase compensator in a capacitive current feedback loop, and the stability of the system and the quality of grid-connected current are improved. According to the invention, composite control is realized by adopting a mode of combining a capacitor current sampling modification mode and a delay compensation link addition mode.

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

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

The utility model relates to a kind of motor rotor structure for realizing rotor flux better sinusoidal distribution, belong to motor technical field, including protective shell, the protective shell is located in rotor, the rotor and protective shell are equipped with stator, the rotor is equipped with magnetic separation slot and magnetic filling slot, the magnetic filling slot is inserted and embedded permanent-magnetic strip, the permanent-magnetic strip includes permanent magnet I, permanent magnet II and permanent magnet III. Permanent magnet I and permanent magnet II, permanent magnet III superposition realizes rotor flux better sinusoidal distribution. Permanent magnet I, permanent magnet II, permanent magnet III and magnetic separation slot jointly form cross-axis magnetic circuit, due to the formation of reluctance torque superposition, thereby increase torque. By optimizing rotor magnetic pole shape, permanent magnet arrangement and auxiliary structure are realized, to reduce harmonic content, improve torque stability. Realize the good sinusoidal distribution of rotor flux, low motor torque ripple and slot effect, to improve the stability of motor operation, efficiency and control accuracy.

The application relates to the technical field of reluctance rotary transformers, in particular to a reluctance rotary transformer and a rotor profile design method thereof, which comprises a stator and a rotor, eight stator teeth with the same parameters are arranged on the inner wall of the stator; a stator tooth winding is further arranged on the stator, the profile vector radius of the rotor is r(ptheta), r(ptheta)=r1+lambda-l(ptheta), wherein r1 is the base circle radius of the salient pole rotor, lambda is the distance from the inner surface of the stator tooth pole shoe to the base circle of the rotor, l(ptheta) is the air gap length between the inner surface of the stator tooth pole shoe and the rotor; wherein p is the pole pair number of the rotor, theta is the mechanical rotation angle of the rotor, A is the inner surface area of the stator tooth pole shoe, mu0 is the air permeability, I m is the coil excitation current, N is the excitation winding number, phi m is the average magnetic flux, and delta is the amplitude modulation coefficient. In the case that the shape of the stator is determined, the rotor profile is designed through air gap change, so that the harmonic content of the output signal of the reluctance rotary transformer can be well reduced.

The invention relates to the technical field of Vienna rectifiers, in particular to a control method for improving harmonic power grid input adaptability of a Vienna rectifier, which comprises the following steps of: performing coordinate transformation on acquired three-phase power grid voltage and input current to obtain voltage and current signals under a fundamental wave rotating coordinate system, extracting a fundamental wave current error signal, and calculating the harmonic power grid input adaptability of the Vienna rectifier; the method comprises the following steps: acquiring a current error component of each harmonic, converting the current error component into a rotating coordinate system corresponding to each specified harmonic to obtain the current error component of each harmonic, and in each harmonic rotating coordinate system, independently controlling the current error component of the corresponding harmonic by adopting a proportional-integral controller to generate a control voltage component of each harmonic; inversely transforming the control voltage component of each harmonic to a fundamental wave rotating coordinate system, and superposing to form a total harmonic compensation voltage; according to the invention, by adopting the control method of combining the self-adaptive loop parameters with the bus lifting strategy, the adaptability of the input current of the rectifier along with the power grid voltage under the harmonic power grid voltage is enhanced, so that the problem of overcurrent of the rectifier under different working conditions is avoided.

This application relates to the technical field of power optimization and dispatching, and in particular to a flexible control method, system, and power router for a power router. The method includes: when the power router is in operation, real-time acquisition of operating status data; calculation based on the operating status data using a preset flexible dispatching algorithm to obtain a dispatching decision result; adjustment of the power allocation and exchange boundaries between the power router's energy ports based on the dispatching decision result to obtain a flexible operating range; determination of the current operating mode based on the flexible operating range; and control of the power router to execute energy management actions corresponding to the current operating mode based on the current operating mode and operating status data. By constructing a flexible operating range, the system's adaptability and operational stability under varying operating conditions are improved, achieving rapid response in the time dimension and multi-port coordination in the spatial dimension for energy dispatching, comprehensively enhancing the operating efficiency and control accuracy of the power router.

The invention provides a rotor structure and a motor. The rotor structure comprises a rotor body and a plurality of magnetic bodies. The rotor body comprises a rotor yoke part and a plurality of rotor salient poles, the rotor salient poles are arranged on the outer circumferential surface of the rotor yoke part, and the plurality of rotor salient poles are arranged at intervals along the circumferential direction of the rotor yoke part; a mounting groove is formed between every two adjacent rotor salient poles; the magnetic bodies are arranged in the mounting grooves, and the plurality of magnetic bodies and the plurality of rotor salient poles are alternately arranged; grooves are formed in the side faces, making contact with the magnetic bodies, of the rotor salient poles. The motor comprises the rotor structure. The grooves are formed in the side faces, making contact with the magnetic bodies, of the salient poles of the rotor, magnetic leakage can be reduced, the sine degree of air gap flux density can be improved, the use amount of the magnetic bodies is reduced, meanwhile, counter electromotive force is effectively improved, the harmonic content of the counter electromotive force is reduced, and the operation performance of the motor can be improved, such as torque pulsation and noise reduction.

This application provides a rotor assembly and a motor. The rotor assembly includes a rotor body, a plurality of first permanent magnets, a plurality of second permanent magnets, and a plurality of third permanent magnets. The plurality of first permanent magnets are disposed between the outer surface of the rotor body and the wall of the shaft hole, and are arranged sequentially at intervals along the circumference of the shaft hole. The plurality of second permanent magnets are disposed on the outer surface of the rotor body and are arranged sequentially at intervals along the circumference of the rotor body. Each second permanent magnet corresponds to at least one first permanent magnet, and each second permanent magnet and its corresponding first permanent magnet form a magnet group. Any two adjacent magnet groups constitute a first series magnetic pole circuit structure. The plurality of third permanent magnets are disposed between the outer surface of the rotor body and the wall of the shaft hole, and are arranged sequentially at intervals along the circumference of the shaft hole. A third permanent magnet is provided between two adjacent magnet groups. Any third permanent magnet and the second permanent magnets of two adjacent magnet groups constitute a second series magnetic pole circuit structure, thereby balancing power density and response speed.

The utility model relates to the technical field of motor stators, in particular to a stator punching sheet which comprises an integrally annular yoke portion, tooth portions evenly distributed along the circumference are arranged in the yoke portion, a tooth groove is formed between every two adjacent tooth portions, one side, close to the yoke portion, of each tooth groove is in an arc shape, the other ends of the tooth portions are all provided with shoe portions, and the shoe portions are arranged on the yoke portion. The shoe part is arc-shaped, the arc length of the shoe part is smaller than that of one side, close to the yoke part, of each tooth groove, and heat dissipation grooves are evenly distributed in the surface, corresponding to the tooth grooves, of the yoke part. The torque output by the motor can be effectively improved, and meanwhile the service life of the motor can be prolonged.

The invention discloses a remote control compensation device capable of bidirectional reactive power compensation and harmonic treatment, and belongs to the technical field of electric energy quality treatment. The problems that an existing device can only provide fixed reactive power compensation and cannot provide needed reactive power compensation according to reactive power changes are solved; and only capacitive compensation is mainly used, the requirement of compensating inductive reactive power cannot be met, and meanwhile, remote control cannot be realized. The remote control device capable of bidirectional reactive compensation and harmonic suppression is applied to the power distribution network, so that the power transmission capacity of the power distribution network and the power supply capacity of a rural power grid distribution transformer can be effectively improved, and the requirements of energy conservation and consumption reduction of the low-voltage power distribution network are met. Meanwhile, the voltage level of the power distribution area can be effectively adjusted, reactive power in the system can be compensated in real time, normal voltage of users at the tail end of the area during the load peak period is guaranteed, three-phase load balance of each node of the area is achieved, and the power supply quality of the area is remarkably improved.

The application relates to a power distribution network configuration optimization method and device based on harmonic compensation and network loss suppression, a computer device, a storage medium and a computer program product. The method comprises the following steps: obtaining each harmonic impedance of each branch of a power distribution network, each harmonic mutual impedance between nodes, an association matrix formed between all nodes and all branches, each harmonic current of each node and each harmonic voltage of each node when no shunt active power filter is configured; determining a target function and a target condition of shunt active power filter configuration of the power distribution network, solving the target function through a multi-objective particle swarm optimization algorithm, obtaining a global platonic optimal solution set of the target function, and determining a final total configuration capacity scheme of the shunt active power filter from the global platonic optimal solution set under the target condition. The method can improve the power quality of the power distribution network.

This invention provides a rotor and a motor. The rotor (10) has multiple permanent magnet slots (11). Any two adjacent permanent magnet slots (11) are symmetrical about a second center line (2). The outer contour of the rotor (10) between any two adjacent second center lines (2) is symmetrical about a first center line (1), and includes: a first arc segment (101) located in the middle, two second arc segments (102) extending outward from both ends of the first arc segment (101), two transition segments (103) extending outward from the two second arc segments (102), and two third arc segments (104) extending outward from the two transition segments (103); the center and radius of the second arc segments (102) are different from those of the first arc segment (101). The rotor of this invention reduces torque pulsation and improves motor efficiency without increasing manufacturing difficulty and cost.

The utility model provides an energy storage converter. The energy storage converter comprises a plurality of DC side input ends A1, A2, A3,..., An; the H bridge consists of switching tubes Q1, Q2, Q3 and Q4; the switching tubes Qa2, Qa3,..., Qan are respectively connected with the direct current side input ends A2, A3,..., An and the negative electrode of the direct current end of the H bridge; the direct current side input end A1 is connected with the direct current end positive electrode of the H bridge; and the alternating current output end of the H bridge is used as the alternating current output end of the energy storage converter. The direct-current side input end A1 is connected with the positive electrode of a series direct-current power supply; the series direct-current power supply is formed by connecting n independent direct-current power supplies with the voltage of Vdc in series; and the direct current side input ends A2, A3,..., An are respectively connected with the negative electrode of each independent direct current power supply according to the potential from high to low. The scheme of the utility model is a hybrid topological structure combining multi-level direct-current voltage selection and the standard H bridge, and compared with a typical high-voltage direct-hanging converter formed by cascading a plurality of H bridges, the scheme of the utility model has the advantage that the usage amount of switch tubes is obviously reduced.

This invention relates to wireless power transfer technology, specifically a single-tube inverter AC envelope modulation wireless power transfer system and control method. The system includes a transmitter and a receiver. The transmitter includes an input AC power supply, a dual-winding AC transformer, a rectifier and filter circuit, a DC / DC module, a single-tube inverter transmitter circuit, a first control module, and a drive circuit module. The receiver includes a receiving circuit, a high-frequency envelope demodulation network, an electrical load, a zero-crossing detection module, and a second control module. The zero-crossing detection module detects the output envelope voltage state to obtain a control signal, and the first control module controls the step-up / step-down state of the DC / DC module based on the envelope state. The advantages are: compared to traditional AC-AC envelope modulation wireless power transfer systems, it further simplifies the circuit structure, reduces the number of switching devices and the drive circuit, further simplifies the control strategy, reduces the harmonic content on the system input side, increases the power factor, and reduces the impact of the input voltage waveform.

The application relates to the technical field of motor drive control, and discloses a common-mode voltage suppression method and system based on model predictive current control, which comprises the following steps: obtaining current values and electrical angular velocities of a permanent magnet synchronous motor at a current time, and obtaining current given values; for Q voltage vectors of an inverter, current prediction models are adopted and combined with the current values and the electrical angular velocities to respectively predict current prediction values at a next time; based on the current prediction values and the current given values, a cost function containing a current tracking error term and a common-mode voltage suppression term is constructed, and based on current deviations and deviation change rates, weight coefficients of the current tracking error term and the common-mode voltage suppression term are determined through a fuzzy controller; the Q voltage vectors and corresponding current prediction values are respectively substituted into the cost function for evaluation, an optimal voltage vector is determined according to a cost function value, and a switching state corresponding to the optimal voltage vector is applied to the inverter. The common-mode voltage can be effectively suppressed while the current tracking performance is guaranteed.