222results about How to "Suppression of torque ripple" patented technology

The invention relates to a permanent-magnet synchronous motor torque ripple suppression method based on coordinate transformation harmonic compensation. Three-phase current is acquired and converted into stator current in a two-phase static coordinate system; the stator current in the two-phase static coordinate system is transformed to fifth, seventh, eleventh and thirteenth harmonic rotating coordinate systems; direct-current component is extracted from fifth, seventh, eleventh and thirteenth harmonic current in the corresponding coordinate systems through a low-pass filter; a second-order low-pass digital filter based on speed adaptation is designed to extract harmonic of a specific order; and on the basis, a proportional integral current controller with cross coupling is designed to complete harmonic current suppression ultimately, thus suppressing torque ripple. Compared with the prior art, the harmonic content of output current can be reduced, and torque ripple, vibration noise and other negative effects of a permanent-magnet synchronous motor for electric vehicles can be reduced on the basis of permanent-magnet synchronous motor vector control.

The invention relates to a magnetic linkage self-control direct torque control method of a brushless DC motor, and belongs to the field of speed regulation of brushless DC motors. The control method solves the problem that the existing method complicates a system control method due to the adoption of double closed-loop regulation of torque and motor magnetic linkage. The control method comprises the following steps: calculating by using a speed calculation unit according to a signal output by a position sensor to obtain a rotor angular velocity of the brushless DC motor; estimating the back-emf of the motor by using a back-emf sliding mode observer according to a current value, a voltage value and the rotor angular velocity; calculating by using the torque estimation unit to obtain the torque Te of the brushless DC motor; regulating by using a torque hysteresis regulator to obtain a control parameter tau after solving the difference between the Te and the predetermined torque Te<*> of the brushless DC motor; and combining the signal output by the position sensor, and generating a corresponding switching signal by a voltage vector selecting unit to control an inverter so as to drive the brushless DC motor to operate. The magnetic linkage self-control direct torque control method is used for the speed regulation control of the brushless DC motor.

The invention relates to a method for suppressing the torque ripple of a permanent-magnet motor based on space vector modulation. The method comprises the following steps of: adopting a vector control strategy that a permanent-magnet motor has a zero direct axis current so that electromagnetic torque and a quadrature axis armature current form a linear connection; and solving an additional quadrature axis injection harmonic current according to the linear connection of the electromagnetic torque of the permanent-magnet motor and the quadrature axis armature current so that an additional electromagnetic torque high-harmonic component generated by coupling the quadrature axis injection harmonic current and the direct axis permanent-magnet chain and fundamental and high-harmonic components in the orientation torque of the permanent-magnet motor have identical amplitude and opposite phases and can be mutually counteracted to suppress the torque ripple. The invention adopts the permanent-magnet motor as an implementation object, and the motor of the type can adopt advanced control protocols of vector control, direct torque control, and the like so that the method is simple and practical by editing control software without increasing the hardware cost of a control system and can obviously suppress the torque ripple of the motor and remain the constant motor characteristics of idling magnetic potential, torque output capability, and the like.

The invention discloses a stator flux linkage set method of brushless DC motor direct torque control, a given rotor flux linkage psif* and a given stator armature reaction flux linkage psia* are respectively set, and a given stator flux linkage psiS* is obtained by performing resultant vector on the above two parts. In the invention, the stator flux linkage set coincides with the running track of the stator flux linkage with an ideal control system, and the brushless DC motor direct torque control system has stable running and good control performance; the flux linkage set value can be dynamically and automatically adjusted along with the change of the working condition of the control system, thus inhibiting motor torque pulsation and improving running efficiency of the system.

The invention discloses a polyphase permanent magnet synchronous motor current waveform optimal control method, comprising the following steps of A, current reference value coordinate transformation; B, current multiple proportion resonance regulation; and C, coupling compensation. In the control method, based on polyphase permanent magnet synchronous motor vector control, a polyphase synchronous rotating coordinate system current reference value is transformed to a current reference value of each phase in a polyphase static coordinate system through polyphase coordinate transformation, the current reference value of each phase and a current feedback value of each phase of a motor are respectively subjected to improved multiple superposition proportion resonance regulation, and a resonance separation method is introduced, decoupling is realized by feed-forward compensation, and floating tracking and harmful subharmonic restraining for highly dynamic property fundamental waves and usable subharmonic are realized. The method can restrain the adverse impacts, such as motor loss, torque ripple and vibration noise, caused by a harmful harmonic current of the polyphase motor, can explore the positive effects of the usable harmonic current, gives full play to the advantages of the polyphase motor and improves the system performance.

The invention discloses a model prediction torque control method based on duty ratio. The method comprises the following steps: adding six virtual vectors on the basis of six basic effective vectors of the existing motor, and establishing a rotary coordinate system directed by a stator flux at the same time; dividing into four sectors according to the torque and flux increase-decrease demands, reducing the number of the candidate vectors and reducing the computing time if each sector in each control period comprises three candidate vectors; for three candidate voltage vectors, respectively computing the torque duty ratio with torque error as zero and the flux duty ratio with flux error as zero, at the end of this control period, of three candidate vectors according to the torque error andthe flux error, and providing a new optimal evaluation method according to the torque duty ratio and the flux duty ratio, wherein the optimal evaluation method does not need the evaluation function inthe tradition method, and the weight coefficient problem is eliminated; and the duty ratio algorithm is added to inhibit the torque pulse caused by the traditional single vector effect control at thesame time; the torque and the flux are simultaneously controlled when the weight factor problem is eliminated, and the torque and the flux have better control effect.

The invention discloses a non-flux observation doubly-fed induction generator low voltage ride-through control method and a system, which can be applied to excitation control on a rotor-side converter of the doubly-fed induction generator in the case of deep power grid fault. The specific implementation method comprises steps: once deep fault is detected to happen to the power grid, rotor current of the doubly-fed induction generator is instantly controlled to directly track stator current at a certain ratio, and a certain compensation term related to stator voltage is injected to a rotor current instruction for providing dynamic reactive support. The invention also provides a control system structure diagram for realizing the above principle. Compared with de-excitation control, flux tracking and other low voltage ride-through excitation control methods, no flux observation step is needed for generating a transient control instruction, the structure is simple, multiple control objectives such as electromagnetic torque ripple suppression or dynamic reactive power compensation can be realized, and the low voltage ride-through ability of the doubly-fed induction generator is greatly enhanced.

The invention discloses a torque-current neural network switch reluctance machine control method and system, and the method comprises the steps: configuring one neural network feedforward controller for each phase of an SRM, taking a torque-current inverse model as an activation function, taking the reference torque, distributed through given total torque, of each phase and the rotor position angle as the input, and achieving the feedback error learning through the output of a PID controller. The output of the neural network feedforward controller and the output of the PID controller are superposed to serve as a reference current which is transmitted to a current hysteresis loop controller, so as to control the operation of the SRM through combining with a current feedback signal at a current moment. The system SRM is provided with the current, position and torque sensors, and a signal processor comprises three neural network feedforward controllers, a torque distribution module, a PID control module and a current hysteresis loop control module. An inner loop current hysteresis loop controller tracks a reference current, and controls the operation of the SRM. The method gives full consideration to the special high nonlinearity of the SRM, and effectively reduces the torque pulsation of the SRM.

The invention discloses a method for restraining torque ripple of a permanent magnet motor based on direct torque control. The direct torque control strategy is adopted in the permanent magnet motor, an additional harmonic torque is directly added based on a given electromagnetic torque so that amplitudes of fundamental components and higher harmonic components in the additional harmonic torque and a position torque are equal and the opposite phases of the fundamental components and the higher harmonic components are opposite and are counterbalanced so as to restrain the torque ripple. The invention is suitable for manufactured motors or purchased finished motors, and particularly permanent magnet motors with larger position torque. The invention has the advantages of low cost by only modifying the control software instead of increasing a drive control cost of the motor, and simplicity, validity and good universality.

The invention belongs to the field of electromechanical control, and discloses a sensorless model prediction flux linkage control method for a permanent magnet synchronous motor. The method comprisesthe following steps: firstly, observing a motor rotating speed omega and a rotor position angle theta e through a sliding mode observer and a phase-locked loop based on SOGI; then, making the given rotating speed omega* and the rotating speed omega pass through a rotating speed loop SMC controller to obtain a given torque Te*; then, observing a load disturbance value according to the rotating speed omega and d/q axis current id/iq, and compensating the load disturbance value to the given torque Te* in a feedforward manner; and finally, substituting the observed rotating speed omega, the rotorposition angle theta e, the given torque Te*, the load disturbance value, the sampled three-phase voltage ua/ub/uc, the three-phase current ia/ib/ic and the like into a model prediction flux linkage control module for operation. According to the method, by adopting the mode of the sliding mode observer and the improved phase-locked loop, the rotor position estimation precision is improved; based on model prediction flux linkage control, setting of current loop parameters and weight coefficients is not needed; and sliding mode control and the load disturbance observer are combined, so that thesystem robustness and the anti-interference capacity are improved.

The invention provides a control method and system for a switched reluctance motor, for solving the technical problem of large torque pulsation when the switched reluctance motor operates. The controlmethod comprises the following steps: obtaining a given rotational speed of a switched reluctance motor; acquiring a rotor position signal of the switched reluctance motor and the phase current of each phase; calculating the feedback rotational speed of the switched reluctance motor according to the rotor position signal; calculating the desired torque of the switched reluctance motor according to the given rotational speed and the feedback rotational speed; according to the desired torque, distributing the output torque of each phase of the switched reluctance motor, and calculating the desired current of each phase of the switched reluctance motor according to the output torque of each phase of the switched reluctance motor; according to the desired current and phase current of each phase of the switched reluctance motor, adopting a neural network adaptive robust sliding mode control algorithm to generate a corresponding driving signal, and controlling the switched reluctance motoraccording to the driving signal. The control method and system for the switched reluctance motor in the invention can effectively suppress the torque pulsation of the switched reluctance motor.

The invention relates to a torque control method and system of a current nonlinear compensated switched reluctance motor. According to the method, a basic control current is calculated by an electromagnetic torque mathematical expression of a linear induction model of the switched reluctance motor, a set torque is allocated to allocation torques of a switch-on phase and a switch-off phase by an optimal torque-sharing function, and the basic control current of each phase is acquired through conversion; and a nonlinear current compensation value of each phase is figured out and is superposed to the basic control current of each phase to serve as the control current of each phase, and a current hysteresis loop controller is controlled according to the difference between the control current and actually-measured current. A microprocessor of the system is connected with three current sensors and a rotor position angle and torque sensor on the switched reluctance motor, a program storage is provided with a data acquisition module and each calculation module of the method, a control signal is obtained by calculation according to each actually-measured signal, and a pulse width modulator controls three-phase input current of the switched reluctance motor. By the method and the system, the torque ripple of the switched reluctance motor is effectively suppressed, an embedment system can be constructed, and on-line control is facilitated.

The invention discloses a triaxial stable platform and an all-digital control system and method. The triaxial stable platform solves the problem that the existing stable platform has a smaller size, harsh structural adaptability and higher use performance requirements. The triaxial stable platform creatively utilizes small-scale high-precision inertial instruments such as fiber optic gyroscopes, photoelectric encoders and brushless torque motors and utilizes a novel distribution and digitization form of a stable loop computer, a high-speed serial bus and an inertial instrument data acquisitionunit so that the stable system size is greatly reduced. The triaxial stable platform utilizes a synchronous clock as a frequency marker so that inertial data acquisition, control rate calculation andtorque current transmission are realized. The brushless torque motor performs current vector control. The stable loop computer realizes a fiber-optic gyroscope error compensation method and integraldelay control strategy through a high-performance digital signal processor and realizes platform coordinate system stabilization along an inertial space direction.

The invention discloses a fault-tolerance control method of a multi-mode dual-channel switched reluctance motor system. A stator, a rotor, two sets of windings and two standard three-phase inverters are included. A star connection mode is adopted by the two sets of windings, and neutral points are connected together. The two standard three-phase inverters drive the two sets of windings to form themulti-mode dual-channel switched reluctance motor system. The system has two operation modes. An operation mode 1 is a traditional three-phase switched reluctance motor operating mode driven by an H-bridge inverter, and driving current is a square wave. An operation mode 2 is a double-inductance coupled switched reluctance motor mode, and the drive current is a sine wave. When the system has a switch device fault, the operation mode 1 is selected to carry out fault-tolerance control, and when the system has a phase open-loop fault, the operation mode 2 is selected to carry out fault-tolerancecontrol. According to the fault-tolerance method, the remaining control freedom of the system after the fault is fully used, the invariability of an average output torque before and after the fault is ensured, and the torque ripple can be effectively reduced.

The invention discloses a low-speed torque ripple restraining device based on direct current voltage adjustment. The low-speed torque ripple restraining device comprises a Buck converter, a voltage type inverter and a controller, wherein the output end of the voltage type inverter is connected with a three-phase winding of a brushless direct current motor; the output end of the controller is connected with a Hall signal output end of the brushless direct current motor; the output end of the controller is connected with each of the voltage type inverter and the Buck converter and is used for controlling working states of the voltage type inverter and the Buck converter; the output end of the Buck converter is connected with the input end of the voltage type inverter. According to the low-speed torque ripple restraining device, torque ripple can be restrained by a mode of adjusting bus voltage. The invention also discloses a restraining method for the low-speed torque ripple restraining device based on the direct current voltage adjustment.

A motor control device includes control calculation means formed by an open loop control unit and a dq-axis/3-phase conversion unit. The open loop control unit obtains voltage instruction values vd, vq on the d-axis and q-axis according to current instruction values id*, iq* on the d-axis and q-axis, the armature winding interlinking magnetic flux quantity f, and the rotor angular velocity omega e in the motor. The dq-axis/3-phase conversion unit converts the voltage instruction values vd, vq into phase voltage instruction values Vu, Vv, Vw. On the other hand, a data acquisition unit acquires angle-dependency data indicating dependency on the electric angle indicated by a secondary higher harmonic component concerning the electric angle of the d-axis or the q-axis component of the motor current according to the current detection value ia and the electric angle theta. A correction coefficient decision unit decides a correction coefficient for correcting the phase voltage instruction value so as to reduce the dependency according to the angle-dependency data. A correction execution unit corrects the phase voltage instruction values Vu, Vv, Vw obtained by the dq-axis/3-phase conversion unit, according to the decided correction coefficient.

A model prediction-direct torque control method for a permanent magnet synchronous motor belongs to the technical field of control. The object of the invention is to complete the accurate estimation of torque and flux linkage in a system by using a reduced-order observer, and then to design the model prediction-direct torque control method for a permanent magnet synchronous motor of a hub motor drive system controller through a model prediction control algorithm. The steps include: selecting motor torque and flux linkage as state variables, selecting an objective function enabling the minimumerror between a predicted value and an expected value of torque and flux linkage, and obtaining three-phase voltage for controlling the motor to finish control over the PMSM. The model prediction control algorithm applied by the invention can effectively deal with the multi-input multi-output and multi-constraint optimization control problems, replaces a hysteresis loop comparator and a switch selection module of conventional direct torque control, avoids the upper and lower limit pulsation of the hysteresis loop and unnecessary switching losses, and effectively suppresses the torque pulsationof the drive motor.

The invention provides a switched reluctance motor with torque pulsation inhibited by permanent magnetic flux, belongs to the motor field, and aims to solve the problem of unobvious effect of the prior method for inhibiting the torque pulsation of the switched reluctance motor. In the switched reluctance motor, a stator and a rotor both have a salient-pole structure; two permanent magnets are symmetrically embedded along the radial direction inside the external circle surface of a stator core, and are arranged in stator cores corresponding to stator phase windings in the radial direction; the magnetic flux direction generated by the permanent magnets is in accordance with the magnetic flux direction of excitation generated by a stator winding; and the stator winding generates a magnetic field to cover the permanent magnets. When the stator winding is not electrified, the permanent magnets and the stator core form a loop, and do not generate a torque to the motor rotor. After the stator winding is electrified, the torque generated by the permanent magnets is changed into positive from negative; when the torque generated by the permanent magnets is negative, a torque wave crest is inhibited; and when the torque generated by the permanent magnets is positive, a torque wave trough is compensated, so that the torque pulsation of the switched reluctance motor is effectively inhibited.

The invention discloses a variable universe fuzzy electric pitch control method for optimizing parameters, and relates to three-closed-loop (namely a current loop, a velocity loop and a position loop) control established by an electric pitch system. Through analyzing the structure of contraction-expansion factors of the variable universe, the parameters thereof can be optimized by genetic algorithm, the intelligent optimization of the parameters can be realized, and a reasonable mechanism for determining the contraction-expansion factors can be established. According to the invention, the optimized variable universe fuzzy control algorithm is applied to the velocity and position control for the electric pitch system, and the appropriate target function is established according to control objectives of the velocity loop and the position loop, so that the optimal control performance of a variable universe fuzzy controller can be realized. The torque pulsation is efficiently inhibited, the dynamic and steady performances of the system are improved, and finally the quick and accurate tracing of the pitch angle position is realized, therefore, an efficient and practical control method is provided for the wind power pitch system.