2023 results about "Flux linkage" patented technology

The invention discloses a modulating method for the optimized PWM of restrainable harmonic waves, which utilizes the combination of space voltage vectors (SVPWM) to realize the elimination of 'm' ('m' equals to 6 multiplied 'j' and plus or minus1; 'j' equals to 1, 2, ellipsis) times of harmonic wave, wherein, 'm' refers to a certain odd number which is not divisible by 3 and comprises 5, 7, 11, 13, etc. The method of the invention is characterized in that the method can be realized by programming, thereby not only solving the problem of calculated amount or look-up table memory capacity existing in a SHEPWM method, using the combined voltage vector to approach the circular trace of a flux linkage, and helping to reduce torque pulsation, but also fulfilling the task of selectively eliminating the harmonic wave.

This invention relates to detecting, analyzing method and devices of permanent magnetic field deformation in permasyn motor. It is in the electric machine control technique field. This method is based on signals which are easy to detect such as voltage, current, electric engine rotate speed, location of the rotor, and so on. To get a real-time observation to the changing state of permasyn motor permanent magnetic field and calculate the back electromotive force coefficient, the permanent magnetic flux linkage on magnetic field synchronous revolution dq coordinate system of permasyn motor. Then the harmonic component in permanent magnetic waveform reflected motor phase winding back electromotive force coefficient by analyzing the back electromotive force. According as those methods, the optimizing control can be applied to forecast and prevent status of excitation losing in permasyn motor. The outcome has already reached can apply to excitation losing online detecting and high performance control of electric engines.

The invention discloses a sensorless control system of a permanent magnet synchronous motor. The sensorless control system comprises a flux linkage/current state observer and a counter electromotive force measurement module, wherein the flux linkage/current state observer is a sliding mode observer; the sliding mode observer is controlled by a sliding mode variable structure; and the coordinate system of the sliding mode observer is an estimated rotary coordinate system, is rotated at an angular speed and lags behind an electrical angle of the coordinate system. In a control parameter computation module, the error of a rotor position is calculated. The sensorless control system of the permanent magnet synchronous motor, can be used on a low-speed observation occasion and a height observation occasion at the same time and has strong practicability.

The invention relates to an induction motor stator resistance and temperature parameter identifying method. A control method based on model reference self-adaption is used for identifying the induction motor stator resistance and the stator winding temperature. According to the calculating method of an asynchronous motor rotor magnetic chain, the current magnetic chain calculating model is used as a reference model, a voltage magnetic chain calculating model is used as an adjusting model, and the output difference between the two models is used for continuously adjusting the stator resistance parameter in the voltage model through the self-adaption rate until the output difference of the two models is zero. The invention can effectively identify the stator resistance parameter and the stator winding temperature of the asynchronous motor in running, enhance the low-frequency property of the direct torque frequency-variable speed adjusting system of the asynchronous motor, eliminate the use of the temperature sensor, and save the cost of the speed adjusting system.

The invention discloses a direct torque control device and a direct torque control method for a permanent magnet synchronous motor. The DC bus voltage of an inverter and a current signal of the permanent magnet synchronous motor are output to a signal detection circuit; the signal detection circuit outputs the DC bus voltage and the current signal to a processor; meanwhile, a rotating speed pulse signal of the permanent magnet synchronous motor is output to the processor and is processed by the processor to form a proper switch signal which is then output to the inverter so as to control the motor. A proper voltage vector is selected from twelve synthesized voltage vectors according to a flux linkage error and a torque error and the position of the flux linkage in twelve sectors, and the duty ratio of the selected voltage vector is determined in real time according to the torque error so as to generate a proper inverter switch signal for controlling the permanent magnet synchronous motor. The number of the selectable voltage vectors in the traditional direct torque control is increased, the duty ratio of an acting vector is adjusted in real time according to the torque error, and the torque pulsation in the traditional direct torque control can be effectively reduced.

The invention discloses a dead-beat based direct torque control method for a permanent magnet synchronous motor. Errors between given magnetic linkage amplitude and actual magnetic linkage amplitude as well as between given torque amplitude and actual torque amplitude are compensated accurately and simultaneously within a control cycle, and dead-beat control of magnetic linkage and torque is realized. Meanwhile, a space voltage vector modulation method is introduced into a control system to enable switching frequency to be constant. By the control method, system performance can be well improved, magnetic linkage and torque pulsation can be lowered obviously, dynamic response speed of the torque is equivalent to that of a conventional direct torque control scheme, and the direct torque control method basically keeps the advantages of simple structure and fast dynamic torque response.

The invention relates to the technical field of PMSMs, solves a coupling problem during online identification of multiple parameters of a surface-mounted type PMSM, and achieves online decoupling identification of PMSM inductance, stator resistance and rotor flux linkage. Accordingly, the technical scheme adopted by the invention is that an online decoupling identification method of multiple parameters of the PMSM comprises the steps as follows: 1) identifying and coupling analysis of parameters of the PMSM; 2) a decoupling identification strategy, wherein voltage deviation before and after D shaft current injection is used for increasing the order of a motor mathematical equation, so that the decoupling identification of multiple parameters of the surface-mounted type PMSM inductance, the stator resistance and the rotor flux linkage are achieved; 3) neural network identifier design, wherein according to a parameter online identification problem of the PMSM, online identification is performed on motor parameters by adopting a self-adaptive neural network structure and a weight convergence algorithm based on a least mean square algorithm. The method is mainly applied to the design and manufacture of the PMSM.

The invention discloses a surface-mounted permanent magnet synchronous motor sensorless direct torque control method. The method comprises a direct torque control method based on SVPWM and a flux linkage self-adaptive method, a novel method for estimating the positions and the rotating speed of rotors by a sliding mode observer and a novel compound control method which is suitable for self-detecting the positions of the rotors within a full speed range. According to the surface-mounted permanent magnet synchronous motor sensorless direct torque control method, the problem that in traditional SVPWM direct torque control, straight-axis currents are large when a motor is operated in a no-load state or under the condition that the heavy load is suddenly applied is fundamentally solved, the buffeting problem of a traditional sliding mode observer is solved, the phase delay problem of the traditional sliding mode observer caused by a low pass filter is solved, and estimation accuracy of the positions of the rotors when the motor is operated is improved. In addition, the problem that the positions of the rotors are inaccurately estimated when the motor is operated in a low speed and standstill mode is further solved, and the sensorless self-starting function can be achieved.

A linear electrical machine may function as an alternator or a motor. Three annular magnets may be provided that move relative to a core. The magnets may all have a different magnetic orientation. Two magnets may have a north pole oriented in a direction parallel to an axis along which the magnets move relative to the core. Another magnet may have a north pole oriented in a direction perpendicular to the axis. The core may include a plurality of ferromagnetic core elements; and a support structure composed of a composite material defining plural spaces, each for receiving one of the plurality of core elements. The core may further include a core shield disposed on the support structure substantially following a perimeter of the support structure defining an opening through which a reciprocating element can pass. Furthermore, the magnets may be supported in a reciprocating element having a low reluctance ferromagnetic frame there being a clearance gap between the machine core and the reciprocating element, the frame having a thicker section adjacent the gap, so as to desirably increase magnet flux linkage with an armature coil.

The invention provides a method for controlling without-position sensor vector of a doubly-fed wind generator, wherein the control method adopts closed loop algorithm on the basis of a model reference self-adaptive module to indentify the rotor position and the rotary speed of a double fed wind induction generator. The control of the without-position sensor vector is possible, the cost of a generator system is lowered, and the anti-interference ability is improved. Simultaneously, the control method also adopts a method for improving voltage module observation flux linkages to observe a stator flux linkage under a stator static coordinate and a rotor flux linkage under a rotor static coordinate, the method can solve the problems that flux linkage phases which are obtained through observing the flux linkage through adopting a high pass filtering method are advanced and the amplitude is reduced, and the flux linkage which is corresponding with true value phases and amplitude is obtained.

The invention discloses a control method of an alternating voltage sensorless high voltage direct current transmission converter, belonging to the technical field of electrical equipment and comprising the following steps: establishing a stator resistor and an inductor for a virtual motor; building relative position relationships among a current vector, a voltage vector and a flux linkage vector, and analyzing a vectorgram; establishing a converter and flux linkage mathematic model, and calculating a virtual flux linkage vector of a system to obtain a power feedback quantity of the system; acquiring an active control signal and a reactive control signal of the system through a direct power control algorithm, and generating a PWM trigger converter for respectively and independently controlling the active power and reactive power of the system; and utilizing MATLAB simulation software to set up a system model for verifying, and obtaining a systematic selection device when the verification is successful. By utilizing Matlab/Simulink to set up a corresponding simulation model, the designed method is verified to have rapid response speed, the voltage and power after startup can still reach stable values after about 2 power frequency periods and have high steady state precision.

The invention discloses a cooperative control method of high and low voltage ride-through for a doubly-fed wind turbine set. According to the method, according to monitored stator end voltage level of the doubly-fed wind turbine set, the operating state of the doubly-fed wind turbine set is divided into three operating modes, to be specific, a normal node, a low voltage ride-through mode and a high voltage ride-through mode; by modifying a rotor side converter control structure, attenuation of direct current and negative sequence component in stator flux linkage of the doubly-fed wind turbine set after a failure occurs is accelerated, and quick injection of reactive current is made possible; according to rotor three-phase current and direct-current bus voltage level monitored in real time, breakover trigger logic of a hardware protective module is optimized, and operational safety of a set transformer and an alternating-current bus capacitor is protected. Especially, the provided cooperative control of high and low voltage ride-through and a protective scheme are implemented completely on basis of existing low voltage ride-through hardware of the set, no additional hardware protective equipment is required, and a general voltage fault ride-through implementing scheme for handling abrupt changes in grid voltage amplitude is provided.

The invention discloses a speed sensorless vector control method on the basis of a cascaded high voltage inverter, which is characterized by comprising the following steps of: 1, establishing a rotor flux linkage voltage model; 2, establishing a rotor flux linkage current model; 3, identifying a rotating speed, using the rotor flux linkage current model in a two-phase rotating coordinate system in the step 2 as an adjustable model, using the rotor flux linkage voltage model in the step 1 as a reference model, utilizing a model reference adaptive system, and adopting a Popov hyperstability theory to obtain a rotating speed identifying model; 4, obtaining a three-phase sinusoidal voltage reference signal by speed and current double close loop control; and 5, sending the three-phase sinusoidal voltage reference signal to a phase-shifting SPWM (Sinusoidal Pulse Width Modulation) distributing plate, controlling a cascaded power unit by utilizing a phase-shifting SPWM control method and controlling the rotating speed of a motor. Due to the adoption of the method disclosed by the invention, a speed sensor does not need to be arranged on a motor shaft, the defects caused by the installation of a speed encoder are avoided, and the flux linkage and the rotating speed of the motor can be well estimated.

The invention discloses a permanent synchronization motor torque control method based on a sliding mode flux linkage observer. Direct torque control is performed on a permanent synchronization motor through a 3/2 coordinate conversion module, the sliding mode flux linkage observer, an electromagnetic torque calculation module, a rotating speed PI adjustor, a torque PI adjustor, a flux linkage self-adaptation module, an expected voltage calculation module, an SVPWM module and an inverter. The sliding mode flux linkage observer is adopted for estimating the size, phase and rotator speed of stator flux linkage, and set torque is processed through the flux linkage self-adaptation module to obtain a set value of the stator flux linkage. Expected voltage calculation is performed on size and phase estimation values and the set value of the stator flux linkage and the output quantity of the torque PI adjustor, so that two-phase alternating-current voltage reference values on a two-phase static coordinate system are obtained, and then through SVPWM conversion, a switching signal is obtained to drive the voltage source inverter to achieve direct torque control over the permanent synchronization motor.

The invention relates to a permanent magnet synchronous motor low inverter power consumption direct torque control method and device. The permanent magnet synchronous motor low inverter power consumption direct torque control method adopts predictive control strategies. Compared with the space-vector-modulation-based direct torque control and the common direct torque control, the permanent magnet synchronous motor low inverter power consumption direct torque control method has the advantages of enabling the integral inverter switching frequency to be the lowest, optimally using a power device and reducing the switching loss of the inverter due to the facts that predicted values of the torque and the stator flux linkage are predicated according to an interior model of a controller based on the given reference values of the torque and the stator flux linkage and a most suitable switching position for the inverter is obtained through a minimization objective function which comprises the flux linkage, the torque and the average switching frequency within the forecast time domain and enabling online computing time to be greatly reduced due to the fact that the control law is fed back through an offline computing state, maintaining good dynamic performance and robustness of the common direct torque control and maintaining the flux and the torque to be within a corresponding hysteresis range.

The invention relates to a low-voltage traversing control method for a double-fed wind power generation system, which belongs to the technical field of wind power generation. The method comprises the following steps: firstly, the stator flux and the rotor flux of a double-fed generator are calculated according to the stator current and the rotor current of the double-fed generator which are measured by a current sensor; secondly, the stator flux is multiplied by a corresponding proportionality factor to serve as the set value of the rotor flux of the double-fed generator, so as to control therotor flux; and thirdly, the rotor flux is controlled in the way that as feedforward compensation decoupling is performed, closed-loop control is conducted to the decoupled system, and a rotor-side converter is controlled after pulse-width modulation is conducted to the obtained voltage control quantity of a rotor-side converter, so as to achieve low-voltage traversing control during failures. The low-voltage traversing control method provided by the invention has fast response, and very good traversing effect when symmetrical and asymmetrical drop failures of the network voltage occur, meanwhile, and oscillation of output electromagnetic torque of the double-fed generator can be effectively inhibited. The control method is simple and suitable for engineering application.

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 an electromagnetic type energy feedback shock absorber based on a Halbach permanent magnet array. Multiple groups of coil windings are arranged in an outer barrel of a belt trough, which is made of soft magnetic materials, and are introduced into and led out of a rectifying circuit via a lead; an inner barrel is provided with a Halbach permanent magnet array consisting of annular permanent magnets of different polarization directions; and the inner barrel and the outer barrel are connected by a spring. When the shock absorber is installed on a driving automobile suspension, axial relative displacement is generated between the inner barrel and the outer barrel by pavement vibrational excitation action transferred by an axle or wheels, and a coil winding magnetic linkage in the outer barrel is changed to generate induced electromotive force. Because the Halbach permanent magnet array has an obvious single-side strengthening characteristic, a magnetic field of which one side is provided with enhanced magnetic induction intensity is in sinusoidal distribution and has a small higher harmonic; and therefore, the absorber has the advantages of small volume, small quality and good energy recovery performance.

The invention relates to a direct torque control system of a permanent-magnet synchronous motor. According to the control system, an extended kalman filter (EKF) observer is adopted for stator magnetic linkage and rotation speed estimation, according to a mathematical model of the permanent-magnet synchronous motor, the state variable x of the system equals to [Psi alpha, Psi beta, Omega gamma, Theta gamma] T, the input variable mu equals to [mu alpha, mu beta] T, the output variable y equals to [Iota alpha, Iota beta ] T, and state equations and output equations (11) of the system are obtained. The motor rotating speed is used as the input of an automatic data rate changer (ADRC) speed controller, the measurement value Te of the electromagnetic torque is calculated through the obtained stator magnetic linkage, in addition, the measurement value Te and electromagnetic torque given signals are compared, comparison results are used as the input of a space voltage vector pulse generator, and the output of the space voltage vector pulse generator is connected with a voltage source inverter of the permanent-magnet synchronous motor. The direct torque control system has the advantages of good dynamic performance, better stability performance, high robustness and high anti-interference capability.

The invention discloses a control method of an open winding permanent magnet synchronous motor system of a hybrid inverter. The control method comprises the following steps: after acquiring voltage and current of a three-phase stator of a motor, performing three-phase/two-phase static coordinate transformation to obtain voltage and current under a two-phase static coordinate system, thereby obtaining actual feedback values of electromagnetic torque and stator flux linkage; obtaining an initial given value of the electromagnetic torque through a PI (Proportional Integral) controller so as to obtain given values of the electromagnetic torque and the stator flux linkage; then combining output of a capacitor voltage PI controller to obtain final given voltage vectors of two inverters; finally generating a switching signal of the inverters through space vector pulse width modulation; and triggering a switching device of the hybrid inverter to realize direct torque control of the open winding permanent magnet synchronous motor. According to the control method, wide-range operation of low, medium and high speed of the open winding permanent magnet synchronous motor is realized, the electromagnetic torque in a motor acceleration process is increased, the voltage utilization rate of a direct current voltage source is improved, and high-speed constant-power operation of the permanent magnet synchronous motor is guaranteed.

The invention provides a method for acquiring parameters of a permanent magnet synchronous motor (PMSM), which comprises the following steps: measuring direct-current bus voltage; controlling an inverter to output current to the PMSM by adopting a digital hysteresis loop-type pulse modulation demodulation control mode; detecting line voltage and phase current which correspond to input current in the PMSM; and calculating the stator resistance of the PMSM, the magnetic induction strength psif of a permanent magnet excitation flux linkage and/or the inductance value Ld of the d axis and the inductance value of the q axis according to different current output to the PMSM under controlling the inverter. By adopting the method for acquiring parameters of the PMSM, three parameters in the PMSM are accurately calculated, and the control effect of the vector control technology on the PMSM is effectively improved.

The invention belongs to the field of control over a power conversion device for a wind driven generator and relates to a method for controlling current switching of a double-feed wind driven generator rotor under an imbalanced power grid voltage. The method comprises the following steps of: calculating a stator voltage, a stator current and a rotor current under a two-phase static coordinate system; calculating stator voltages and stator currents of a d axis and a q axis under a flux linkage and a synchronous rotation coordinate system; calculating a slip angle and a slip angular velocity; calculating rotor currents of the d axis and the q axis under the rotation coordinate system; calculating stator active power, reactive power and electromagnetic torque; calculating rotor decoupling compensating voltage; naturalizing and calculating corresponding control variables, acquiring a secondary pulse actual value of a controlled variable through a bandpass filter and a lead lag link, subtracting the actual value from a secondary pulse given value, and calculating to acquire a two-time frequency compensation item through a proportional integral (PI) controller; calculating the given value of the rotor current of the d axis under the rotation coordinate system; allowing the difference of a rotation speed given value and a rotational angular velocity actual value to pass through the PI controller, and calculating to acquire the given value of the rotor current of the q axis under the rotation coordinate system; calculating to acquire reference values of rotor voltages of the d axis and the q axis under the rotation coordinate system; and calculating the rotor voltage under the rotor two-phase static coordinate system and generating switch signals which control power devices.

A discrete rotor position estimation method for a synchronized reluctance motor is provided. A d.c.-link voltage V_dc and a phase current I_ph are sensed. A flux-linkage λ_ph of an active phase is calculated from the sensed d.c.-link voltage V_dc and the sensed phase current I_ph. The calculated flux-linkage λ_ph is compared with a reference flux-linkage λ_r. The reference flux-linkage λ_r corresponds to a reference angle θ_r which lies between angles corresponding to aligned rotor position and non-aligned rotor position in the synchronized reluctance motor. An estimated rotor position θ_cal is obtained only once when the calculated flux-linkage λ_ph is greater than the reference flux-linkage λ_r.