Permanent magnet synchronous motor speed prediction control method, device and system

Abstract

The application provides a kind of permanent magnet synchronous motor speed prediction control method, it is related to permanent magnet synchronous motor control technical field, comprising: obtaining the mechanical angular velocity given value, mechanical angular velocity feedback value and dq axis current feedback value of permanent magnet synchronous motor k time;Determine the mechanical angular velocity estimated value of k+1 time, the lumped disturbance estimated value of k+1 time;Determine the dq axis current given value of k time;By the dq axis current given value of k time, the dq axis current estimated value of k+1 time, determine the dq axis voltage given value of k+1 time;The dq axis voltage given value of k+1 time is carried out space vector pulse width modulation, generates switching signal and sends to inverter to control the current and speed of permanent magnet synchronous motor at k+2 time;The method can improve the dynamic performance of permanent magnet synchronous motor speed control, and has strong robustness.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of speed control of permanent magnet synchronous motor, and particularly relates to a speed prediction control method, device and system of permanent magnet synchronous motor. BACKGROUND

[0002] Permanent magnet synchronous motor is widely used as a driving unit of powertrain system due to its advantages of high power density, high torque density and high efficiency. With the rapid development of application scenarios of permanent magnet synchronous motor such as electric vehicles and electro-hydraulic actuators, higher and higher requirements are put forward for the precision and dynamic response of speed control.

[0003] The speed control system of permanent magnet synchronous motor is usually composed of cascades of speed loop and current loop of different time scales. Although high dynamic response control algorithms such as deadbeat current prediction control significantly improve the dynamic performance of the current loop, the bandwidth limitation of the cascade architecture and proportional integral control of the prior art still restricts the further optimization of the dynamic performance of the speed loop, and in complex and variable application scenarios, the dynamic performance cannot meet the requirements. SUMMARY

[0004] Therefore, it is necessary to provide a speed prediction control method, device and system of permanent magnet synchronous motor to improve the dynamic performance of speed control of permanent magnet synchronous motor and have strong robustness.

[0005] In a first aspect, the present application provides a speed prediction control method of permanent magnet synchronous motor, which comprises:

[0006] obtaining a mechanical angular velocity given value of permanent magnet synchronous motor at time k , a mechanical angular velocity feedback value and a dq-axis current feedback value ;

[0007] determining a dq-axis current estimation value at time k+1 through the dq-axis current feedback value at time k and a current prediction equation, and determining an electromagnetic torque estimation value at time k+1 through the dq-axis current estimation value at time k+1 ;

[0008] determining a mechanical angular velocity estimation value at time k+1 through the mechanical angular velocity feedback value at time k and a speed prediction equation, and determining a lumped disturbance estimation value at time k+1 through the mechanical angular velocity feedback value at time k ;

[0009] The mechanical angular velocity given at time k The estimated value of the lumped disturbance at time k+1 The estimated mechanical angular velocity at time k+1 The estimated value of the electromagnetic torque at time k+1 And the torque setpoint calculation equation, to determine the electromagnetic torque setpoint at time k+2. ;

[0010] The electromagnetic torque given at time k+2 Based on the given current calculation equation, determine the dq-axis current setpoint at time k. The dq-axis current given at time k. The estimated dq-axis current at time k+1 Determine the dq-axis voltage setpoint at time k+1. ;

[0011] The given value of the dq-axis voltage at time k+1 Space vector pulse width modulation is performed to generate a switching signal and send it to the inverter. The switching signal is used to control the inverter to output a corresponding voltage to the permanent magnet synchronous motor, so as to control the current and speed of the permanent magnet synchronous motor at time k+2.

[0012] In one embodiment, the dq-axis current feedback value at time k is used. The current prediction equation determines the estimated dq-axis current at time k+1. And the estimated dq-axis current at time k+1. The electromagnetic torque estimate at time k+1 is determined by the torque prediction equation. ,include:

[0013] The current prediction equation is the sum of the first part and the second part, where the first part is the dq-axis current feedback value at time k. The second part relates to the dq-axis voltage setpoint at time k. Regarding the dq-axis current feedback value at time k, and the dq-axis voltage setpoint at time k Substituting into the current prediction equation, we obtain the estimated dq-axis current at time k+1. ;

[0014] The dq-axis current feedback value at time k Substituting into the torque prediction equation, we obtain the electromagnetic torque estimate at time k. And the estimated dq-axis current at time k+1. Substituting the torque prediction equation obtains the electromagnetic torque estimation value at the k+1 moment .

[0015] In one embodiment, the mechanical angular velocity estimation value at the k+1 moment is determined by the mechanical angular velocity feedback value at the k moment and a speed prediction equation The lumped disturbance estimation value at the k+1 moment is determined by the mechanical angular velocity feedback value at the k moment and a disturbance estimation equation , comprising:

[0016] The sum of the electromagnetic torque estimation value at the k+1 moment and the electromagnetic torque estimation value at the k moment is defined as a target torque sum, and the difference between the mechanical angular velocity feedback value at the k moment and the mechanical angular velocity estimation value at the k moment is defined as a target angular velocity difference; wherein the speed prediction equation and the disturbance estimation equation are both obtained based on a discretized mathematical model of a mechanical part of a permanent magnet synchronous motor and an extended state observer, and the discretized mathematical model of the mechanical part of the permanent magnet synchronous motor is constructed based on a super-local model;

[0017] The target torque sum, the target angular velocity difference, the lumped disturbance estimation value at the k moment , and the mechanical angular velocity estimation value at the k moment are substituted into the speed prediction equation to obtain the mechanical angular velocity estimation value at the k+1 moment ;

[0018] The target angular velocity difference and the lumped disturbance estimation value at the k moment are substituted into the disturbance estimation equation to obtain the lumped disturbance estimation value at the k+1 moment .

[0019] In one embodiment, the left side of the torque given calculation equation is the electromagnetic torque given value at the k+2 moment , and the right side of the torque given calculation equation includes a first expression and a second expression; the first expression includes the mechanical angular velocity given value at the k moment , the lumped disturbance estimation value at the k+1 moment , and the mechanical angular velocity estimation value at the k+1 moment , and the second expression includes the electromagnetic torque estimation value at the k+1 moment The electromagnetic torque given value at the k+2 moment in the torque given calculation equation is equal to the first expression minus the second expression.

[0020] In one of the embodiments, the determination of the torque given calculation equation comprises:

[0021] Taking the speed dynamic response time of three control periods as the control target;

[0022] Balancing the electromagnetic torque estimation value at the k+3 moment with the lumped disturbance estimation value at the k+1 moment , and making the mechanical angular velocity estimation value at the k+3 moment equal to the mechanical angular velocity given value at the k moment , to obtain the torque given calculation equation.

[0023] In one of the embodiments, the determination of the torque given calculation equation comprises: Balancing the electromagnetic torque estimation value at the k+3 moment with the lumped disturbance estimation value at the k+1 moment , and making the mechanical angular velocity estimation value at the k+3 moment equal to the mechanical angular velocity given value at the k moment

[0024] Making the electromagnetic torque estimation value at the k+3 moment equal to the lumped disturbance estimation value at the k+1 moment , to obtain the first relationship between the electromagnetic torque estimation value at the k+3 moment and the lumped disturbance estimation value at the k+1 moment ;

[0025] Making the mechanical angular velocity estimation value at the k+3 moment reach the mechanical angular velocity given value at the k moment by the action of the electromagnetic torque in the k+1 and k+2 control periods, to obtain the second relationship between the mechanical angular velocity estimation value at the k+3 moment , the mechanical angular velocity estimation value at the k+2 moment , and the mechanical angular velocity estimation value at the k+1 moment ;

[0026] Based on the first relationship, the second relationship, the mechanical angular velocity estimation value at the k+3 moment equal to the mechanical angular velocity given value at the k moment , and the electromagnetic torque estimation value at the k+2 moment equal to the electromagnetic torque given at the k+2 moment , to obtain the torque given calculation equation.

[0027] In one embodiment, the electromagnetic torque given at time k+2 is used. Based on the given current calculation equation, determine the dq-axis current setpoint at time k. ,include:

[0028] Determine the relationship between the electromagnetic torque setpoint and the dq-axis current setpoint, and substitute the expression for the dq-axis current setpoint into this relationship to obtain the target equation for the electromagnetic torque setpoint and the q-axis current setpoint.

[0029] The electromagnetic torque given at time k+2 Obtain the initial value of the objective equation iteration. The objective equation is iterated using the Newton-Raphson iteration method to obtain the current reference calculation equation; and the dq-axis current reference value at time k is determined based on the current reference calculation equation. .

[0030] In one embodiment, the dq-axis current at time k is given by... The estimated dq-axis current at time k+1 Determine the dq-axis voltage setpoint at time k+1. ,include:

[0031] Obtain the estimated mechanical angular velocity at time k+1. ;

[0032] Based on the estimated mechanical angular velocity at time k+1 Determine the estimated electric angular velocity at time k+1. ;

[0033] The dq-axis current at time k is given by The estimated dq-axis current at time k+1 and the estimated electric angular velocity at time k+1 Substituting into the voltage setpoint calculation equation, we obtain the dq-axis voltage setpoint at time k+1. .

[0034] Secondly, this application also provides a speed prediction and control device for a permanent magnet synchronous motor, the device comprising: a speed-current controller, an inverter, a current detection module and a position detection module;

[0035] The position detection module is used to obtain the mechanical angular velocity feedback value of the permanent magnet synchronous motor at time k. ;

[0036] The current detection module is used to obtain the dq-axis current feedback value of the permanent magnet synchronous motor at time k. ;

[0037] Speed-current controller for mechanical angular velocity setpoint based on time k. Mechanical angular velocity feedback value and dq axis current feedback value The speed prediction control method for a permanent magnet synchronous motor according to any embodiment of the first aspect described above is executed, and the dq-axis voltage setpoint at time k+1 is output. ;

[0038] Inverter, used to provide the dq-axis voltage setpoint at time k+1. Space vector pulse width modulation is performed to generate a switching signal and send it to the inverter. The switching signal is used to control the inverter to output a corresponding voltage to the permanent magnet synchronous motor, so as to control the current and speed of the permanent magnet synchronous motor at time k+2.

[0039] Thirdly, this application also provides a speed prediction control system for a permanent magnet synchronous motor, the system including a permanent magnet synchronous motor and a speed prediction control device of the second aspect, the speed prediction control device being used to control the operation of the permanent magnet synchronous motor.

[0040] The speed prediction control method, device, and system for permanent magnet synchronous motors provided in the above embodiments are based on the mechanical angular velocity setpoint of the permanent magnet synchronous motor at time k. Mechanical angular velocity feedback value and dq axis current feedback value Based on the dq-axis current feedback value at time k Determine the estimated dq-axis current at time k+1. And determine the estimated value of the electromagnetic torque at time k+1. Based on the mechanical angular velocity feedback value at time k Determine the estimated mechanical angular velocity at time k+1. The lumped disturbance estimate at time k+1 Based on the mechanical angular velocity given at time k Calculate the electromagnetic torque setpoint at time k+2. Based on the electromagnetic torque given at time k+2 Determine the dq-axis current setpoint at time k. The voltage-given calculation equation is based on the dq-axis current given at time k. The dq-axis voltage given value at the k+1 moment is calculated, the switch signal is generated by space vector pulse width modulation on the dq-axis voltage given value, the corresponding voltage is output by the inverter to act on the permanent magnet synchronous motor, so as to control the current and the speed of the permanent magnet synchronous motor at the k+2 moment. The speed prediction control method of the embodiment can improve the dynamic performance of the speed control of the permanent magnet synchronous motor, so as to make dynamic adjustment of the speed of the permanent magnet synchronous motor quickly, and has strong robustness. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 A flow chart of the speed prediction control method of the permanent magnet synchronous motor in one embodiment;

[0042] Figure 2 A flow chart of determining the torque given calculation equation in one embodiment;

[0043] Figure 3 Another flow chart of determining the torque given calculation equation in one embodiment;

[0044] Figure 4 A structure schematic diagram of the speed prediction control device in one embodiment;

[0045] Figure 5 A structure schematic diagram of a speed-current controller provided in one embodiment;

[0046] Figure 6 A structure schematic diagram of a speed prediction control system of a permanent magnet synchronous motor provided in one embodiment. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0048] In one embodiment, as shown in Figure 1 , a speed prediction control method of a permanent magnet synchronous motor is provided, which comprises the following steps S101 to S106:

[0049] Step S101: obtaining a mechanical angular speed given value , a mechanical angular speed feedback value and a dq-axis current feedback value of the permanent magnet synchronous motor at the k moment;

[0050] Step S102: determining the torque given calculation equation and the current prediction equation determines the dq-axis current estimation value at k+1 time , and the current prediction equation determines the dq-axis current estimation value at k+1 time and the torque prediction equation determines the electromagnetic torque estimation value at k+1 time ;

[0051] Step S103: the mechanical angular velocity estimation value at k+1 time is determined by the mechanical angular velocity feedback value at k time and the speed prediction equation , the mechanical angular velocity estimation value at k+1 time is determined by the mechanical angular velocity feedback value at k time and the disturbance estimation equation determines the lumped disturbance estimation value at k+1 time ;

[0052] Step S104: the electromagnetic torque given value at k+2 time is determined by the mechanical angular velocity given value at k time , the lumped disturbance estimation value at k+1 time , the mechanical angular velocity estimation value at k+1 time , the electromagnetic torque estimation value at k+1 time and the torque given calculation equation ;

[0053] Step S105: the dq-axis current given value at k time is determined by the electromagnetic torque given value at k+2 time and the current given calculation equation ; the dq-axis voltage given value at k+1 time is determined by the dq-axis current given value at k time , the dq-axis current estimation value at k+1 time ; ;

[0054] Step S106: the dq-axis voltage given value at k+1 time is subjected to space vector pulse width modulation, a switching signal is generated and sent to the inverter, and the switching signal is used to control the inverter to output corresponding voltage to act on the permanent magnet synchronous motor, so as to control the current and speed of the permanent magnet synchronous motor at k+2 time.

[0055] The space vector pulse width modulation is to generate a series of voltage vectors to approximate the ideal rotating magnetic field by accurately controlling the on and off time of the inverter switch, which is used to reduce the distortion of the current waveform and the torque ripple. The switching signal is used to control the inverter to output corresponding voltage to act on the permanent magnet synchronous motor, so as to control the current of the permanent magnet synchronous motor.

[0056] Specifically, first, the dq-axis voltage given value at k+1 time The rotating two-phase coordinate system is transformed into a stationary two-phase coordinate system to obtain a given value of the permanent magnet synchronous motor αβ axis voltage at the k+1 moment ; then, according to spatial vector pulse width modulation is performed to generate corresponding switching signals sent to the inverter.

[0057] The speed prediction control method of the permanent magnet synchronous motor provided in the embodiments of the present application is based on a mechanical angular velocity given value , a mechanical angular velocity feedback value and a dq axis current feedback value at the k moment of the permanent magnet synchronous motor, uses a current prediction equation to calculate a dq axis current estimation value at the k+1 moment according to the dq axis current feedback value at the k moment, uses a torque prediction equation to calculate an electromagnetic torque estimation value at the k+1 moment according to the dq axis current estimation value at the k+1 moment, uses a speed prediction equation and a disturbance estimation equation to calculate a mechanical angular velocity estimation value at the k+1 moment and a lumped disturbance estimation value at the k+1 moment according to the mechanical angular velocity feedback value at the k moment, uses a torque given calculation equation to calculate an electromagnetic torque given value at the k+2 moment according to the mechanical angular velocity given value at the k moment, uses a current given calculation equation to calculate a dq axis current given value at the k moment according to the electromagnetic torque given value at the k+2 moment, uses a voltage given calculation equation to calculate a dq axis voltage given value at the k+1 moment according to the dq axis current given value at the k moment, and the spatial vector pulse width modulation is performed on the dq axis voltage given value to generate switching signals, which are sent to the inverter to control the inverter to output corresponding voltages acting on the permanent magnet synchronous motor to control the current and the speed of the permanent magnet synchronous motor at the k+2 moment. The speed prediction control method of the embodiments of the present application takes the speed dynamic response time of three control periods as a control target, can improve the dynamic performance of the speed control of the permanent magnet synchronous motor, facilitates the dynamic adjustment of the speed of the permanent magnet synchronous motor, and has strong robustness.

[0058] In one embodiment, the dq axis current estimation value at the k+1 moment is determined by the dq axis current feedback value at the k moment and the current prediction equation, and the electromagnetic torque estimation value at the k+1 moment is determined by the dq axis current estimation value at the k+1 moment and the torque prediction equation, and specifically includes the following:

[0059] The current prediction equation is the sum of a first part and a second part, the first part being related to the dq-axis current feedback value at time k The second part being related to the dq-axis voltage given value at time k The dq-axis current feedback value at time k and the dq-axis voltage given value at time k is substituted into the current prediction equation to obtain the dq-axis current estimation value at time k+1 .

[0060] The dq-axis current feedback value at time k is substituted into the torque prediction equation to obtain the electromagnetic torque estimation value at time k and the dq-axis current estimation value at time k+1 is substituted into the torque prediction equation to obtain the electromagnetic torque estimation value at time k+1 .

[0061] In particular, the current prediction equation satisfies the following relationship:

[0062] ;

[0063] wherein: represents the dq-axis current estimation value at time k+1; represents the dq-axis current feedback value at time k; represents the dq-axis voltage given value at time k; ; ; ; represents the estimated value of the stator resistance; represents the estimated value of the d-axis inductance; represents the estimated value of the q-axis inductance; represents the estimated value of the permanent magnet flux linkage; represents the control period; represents the electrical angular velocity feedback value at time k. The first part is and the second part is It should be noted that the time instant represents an instant, and the period represents a period of time, for example, k period means the time period from time k to time k+1.

[0064] In addition, the electrical angular velocity feedback value at time k satisfies the following relationship with the mechanical angular velocity feedback value at time k , represents the number of motor pole pairs.

[0065] In particular, the torque prediction equation satisfies the following relationship:

[0066] ​ .

[0067] In one embodiment, the mechanical angular velocity estimation value at the k+1 moment is determined by the mechanical angular velocity feedback value at the k moment and a speed prediction equation The mechanical angular velocity feedback value at the k moment and a disturbance estimation equation are used to determine the lumped disturbance estimation value at the k+1 moment Specifically, it includes:

[0068] The electromagnetic torque estimation value at the k+1 moment is calculated The sum of the electromagnetic torque estimation value at the k moment is defined as the target torque sum, and the difference between the mechanical angular velocity feedback value at the k moment and the mechanical angular velocity estimation value at the k moment is defined as the target angular velocity difference; wherein the speed prediction equation and the disturbance estimation equation are both obtained based on the discretized mathematical model of the mechanical part of the permanent magnet synchronous motor and the extended state observer, and the discretized mathematical model of the mechanical part of the permanent magnet synchronous motor is constructed based on the hyperlocal model.

[0069] The target torque sum, the target angular velocity difference, the lumped disturbance estimation value at the k moment and the mechanical angular velocity estimation value at the k moment are substituted into the speed prediction equation to obtain the mechanical angular velocity estimation value at the k+1 moment ;

[0070] The target angular velocity difference and the lumped disturbance estimation value at the k moment are substituted into the disturbance estimation equation to obtain the lumped disturbance estimation value at the k+1 moment .

[0071] Specifically, the discretized mathematical model of the mechanical part of the permanent magnet synchronous motor is constructed based on the hyperlocal model.

[0072] Wherein, the hyperlocal model simplifies the mathematical model of the mechanical part of the permanent magnet synchronous motor to a first-order system that models all disturbances as a lumped disturbance term, satisfying the following relationship:

[0073] ,

[0074] Wherein: represents the mechanical angular velocity, represents the electromagnetic torque, represents the load torque, represents the viscous friction torque coefficient, represents other unmodeled torque disturbances, represents the moment of inertia; an estimate of the electromagnetic torque, an estimate of the moment of inertia, a lumped disturbance.

[0075] Since the control period of the digital control is short enough, the electromagnetic torque changes linearly within each control period, the effect of the electromagnetic torque within a control period can be equivalent to the average value of the beginning and end time, and the discrete-time mathematical model of the mechanical part of the permanent magnet synchronous motor based on the super-local model can be obtained, which satisfies the following relationship:

[0076] ,

[0077] wherein: represents the mechanical angular velocity at k+1 time; represents the mechanical angular velocity at k time; represents the estimate of the electromagnetic torque at k+1 time; represents the estimate of the electromagnetic torque at k time; represents the lumped disturbance at k time; represents the control period.

[0078] Further, according to the discrete-time mathematical model of the mechanical part of the permanent magnet synchronous motor, the speed prediction equation and the disturbance estimation equation are determined by combining the extended state observer. The extended state observer based on the mathematical model of the mechanical part of the permanent magnet synchronous motor constructed based on the super-local model satisfies the following relationship:

[0079] ,

[0080] wherein: represents the estimate of the mechanical angular velocity; represents the estimate of the lumped disturbance; and are the gains of the extended state observer. The speed prediction equation and the disturbance estimation equation can be obtained by discretization, and the speed prediction equation and the disturbance estimation equation satisfy the following relationship:

[0081] ;

[0082] wherein: represents the estimate of the mechanical angular velocity at k+1 time; represents the estimate of the mechanical angular velocity at k time; represents the feedback value of the mechanical angular velocity at k time; represents the estimate of the lumped disturbance at k+1 time; represents the estimate of the lumped disturbance at k time; and are the gains of the extended state observer.

[0083] In one embodiment, the equation left side of the torque given calculation equation is the electromagnetic torque given value at the k+2 moment , the equation right side of the torque given calculation equation includes a first expression and a second expression; the first expression includes the mechanical angular velocity given value at the k moment , the lumped disturbance estimation value at the k+1 moment , and the mechanical angular velocity estimation value at the k+1 moment , and the second expression includes the electromagnetic torque estimation value at the k+1 moment , the electromagnetic torque given value at the k+2 moment in the torque given calculation equation is equal to the first expression minus the second expression;

[0084] Specifically, the torque given calculation equation satisfies the following relationship:

[0085] ,

[0086] Wherein: represents the electromagnetic torque given value at the k+2 moment; represents the mechanical angular velocity given value at the k moment. The first expression is , and the second expression is .

[0087] In one embodiment, the torque given calculation equation is determined in the following steps:

[0088] Step S201: taking the rotational speed dynamic response time of three control periods as the control target;

[0089] Step S202: balancing the electromagnetic torque estimation value at the k+3 moment with the lumped disturbance estimation value at the k+1 moment , and setting the mechanical angular velocity estimation value at the k+3 moment equal to the mechanical angular velocity given value at the k moment , to obtain the torque given calculation equation.

[0090] In one embodiment, the torque given calculation equation is determined by balancing the electromagnetic torque estimation value at the k+3 moment with the lumped disturbance estimation value at the k+1 moment , and setting the mechanical angular velocity estimation value at the k+3 moment equal to the mechanical angular velocity given value at the k moment in step S202, specifically including the following steps:

[0091] Step S301: balancing the electromagnetic torque estimation value at the k+3 moment with the lumped disturbance estimation value at the k+1 moment balancing the electromagnetic torque estimation value at k+3 time with the lumped disturbance estimation value at k+1 time , a first relationship between the electromagnetic torque estimation value at k+3 time

[0092] Step S302: the mechanical angular velocity estimation value at k+3 time is obtained by the action of electromagnetic torque in the k+1 and k+2 control periods to the mechanical angular velocity given value at k time , the mechanical angular velocity estimation value at k+3 time is obtained by balancing the electromagnetic torque estimation value at k+3 time with the mechanical angular velocity estimation value at k+2 time , the mechanical angular velocity estimation value at k+1 time , a second relationship between the mechanical angular velocity estimation value at k+3 time

[0093] Step S303: based on the first relationship, the second relationship, the mechanical angular velocity estimation value at k+3 time equals the mechanical angular velocity given value at k time , and the electromagnetic torque estimation value at k+2 time equals the electromagnetic torque given at k+2 time , a torque given calculation equation is obtained.

[0094] Specifically, in the case of considering the unit delay of the digital system without considering the voltage limit, the current loop under the deadbeat current prediction control can be simplified as a second-order unit delay, the mathematical model of the mechanical part of the permanent magnet synchronous motor is a first-order system, and the speed loop is modeled as a third-order linear system. According to the principle of deadbeat control, the shortest dynamic response time of the system will not exceed three control periods, and due to the existence of the unit delay of the digital system, the shortest dynamic response time will not be shorter than two control periods.

[0095] If the speed dynamic response time of two control periods is taken as the control target, the mechanical angular velocity at k+2 time is made to follow the given value at k time, and due to the existence of the unit delay of the digital system, the current and the speed remain unchanged in the kth control period; under the action of the electromagnetic torque in the k+1 control period, the speed reaches the given value at k time at k+2 time, and due to the imbalance between the electromagnetic torque at k+2 time and the lumped disturbance, the subsequent current oscillation will be caused.

[0096] The embodiment of the present application takes the speed dynamic response time of three control periods as the control target, and makes the electromagnetic torque estimation value at k+3 time balances the lumped disturbance estimation value at k+1 time , the mechanical angular velocity estimation value at k+3 time is obtained by the action of electromagnetic torque in the k+1 and k+2 control periods to the mechanical angular velocity given value at k time The estimated mechanical angle at time k+3 It satisfies the following relation, namely the second relation:

[0097]

[0098] in: This represents the estimated mechanical angular velocity at time k+3; This represents the estimated mechanical angular velocity at time k+2; This represents the estimated electromagnetic torque at time k+3; This represents the estimated electromagnetic torque at time k+2.

[0099] Estimated electromagnetic torque at time k+3 Estimated lumped disturbance at time k+1 Balance is achieved by satisfying the following relation, which is the first relation:

[0100] ,

[0101] According to the control objective, let The mechanical angular velocity at time k is given. Let the estimated electromagnetic torque at time k+2 be... The electromagnetic torque given at time k+2 is equal to the given value. The torque calculation equation can be obtained from this.

[0102] In one embodiment, the electromagnetic torque given value at time k+2 in step S105 Based on the given current calculation equation, determine the dq-axis current setpoint at time k. Specifically, it includes:

[0103] Determine the relationship between the electromagnetic torque setpoint and the dq-axis current setpoint, and substitute the expression for the dq-axis current setpoint into this relationship to obtain the target equation for the electromagnetic torque setpoint and the q-axis current setpoint.

[0104] The electromagnetic torque given at time k+2 Obtain the initial values ​​for the objective equation iteration. The objective equation is iterated using the Newton-Raphson iteration method to obtain the current given calculation equation; and the dq-axis current given value at time k is determined based on the current given calculation equation. .

[0105] Specifically, in order to control the torque of a permanent magnet synchronous motor by controlling its current, the dq-axis current setpoint needs to be calculated based on the electromagnetic torque setpoint. Under the maximum torque-to-current ratio control strategy, the dq-axis current setpoint satisfies the following relationship, i.e., the expression for the dq-axis current setpoint:

[0106] ,

[0107] wherein: represents the q-axis current given value at time k; represents the d-axis current given value at time k; represents the estimated value of the d-axis inductance; represents the estimated value of the q-axis inductance; represents the estimated value of the permanent magnet flux linkage.

[0108] The electromagnetic torque given value and the dq-axis current given value satisfy the following relationship:

[0109] ,

[0110] wherein: represents the number of pole pairs of the motor. Substituting the relationship of the dq-axis current given value into the equation, the electromagnetic torque given value and the q-axis current given value satisfy the following relationship, i.e., the target equation of the electromagnetic torque given value and the q-axis current given value:

[0111] ,

[0112] The relationship is a monomial quartic equation about the q-axis current given value, and an analytical solution cannot be directly obtained. Newton-Raphson iteration method is used for solving and calculating. Let x be the root of the equation f(x)=0, and x0 is selected as the initial value of iteration. The iteration format of Newton-Raphson iteration method satisfies the following relationship:

[0113] ,

[0114] wherein: j represents the current iteration number; n represents the total iteration number.

[0115] The initial value of the q-axis current given value is determined as the q-axis current required to generate the same size electromagnetic torque when the d-axis current control strategy is used, which satisfies the following relationship:

[0116] ,

[0117] wherein: represents the initial value of the q-axis current given value at time k.

[0118] It can be obtained that the equation for determining the dq current given value using Newton-Raphson iteration method satisfies the following relationship:

[0119]

[0120] wherein: represents the q-axis current given value at time k in the jth iteration; the q-axis current given value at the k moment of the (j-1)-th iteration; the q-axis current given value at the k moment of the n-th iteration.

[0121] In one embodiment, the dq-axis voltage given value at the k+1 moment is determined by the dq-axis current given value at the k moment , the dq-axis current estimation value at the k+1 moment , specifically comprising:

[0122] obtaining the mechanical angular velocity estimation value at the k+1 moment ;

[0123] determining the electrical angular velocity estimation value at the k+1 moment based on the mechanical angular velocity estimation value at the k+1 moment ;

[0124] substituting the dq-axis current given value at the k moment , the dq-axis current estimation value at the k+1 moment , and the electrical angular velocity estimation value at the k+1 moment into the voltage given calculation equation to obtain the dq-axis voltage given value at the k+1 moment .

[0125] Specifically, the voltage given calculation equation satisfies the following relationship:

[0126] ,

[0127] wherein, in the voltage given calculation equation represents the dq-axis voltage given value at the k+1 moment; represents the dq-axis current given value at the k moment; ; ;

[0128] represents the electrical angular velocity estimation value at the k+1 moment, the electrical angular velocity estimation value at the k+1 moment satisfies the following relationship with the mechanical angular velocity estimation value at the k+1 moment :

[0129] .

[0130] ​​Based on the same inventive concept, the application further provides a speed prediction control device of a permanent magnet synchronous motor for implementing the speed prediction control method of the permanent magnet synchronous motor as described above. The device provides a solution to the problem similar to the implementation scheme described in the above method, so the specific limitations in one or more speed prediction control device embodiments of the permanent magnet synchronous motor provided below can refer to the limitations of the speed prediction control method of the permanent magnet synchronous motor described above, which will not be repeated here.

[0131] In one embodiment, as shown in Figure 4 , a speed prediction control device of a permanent magnet synchronous motor is provided, which comprises: a speed-current controller 403, an inverter 404, a current detection module 402 and a position detection module 401;

[0132] The position detection module 401 is configured to obtain a mechanical angular velocity feedback value of the permanent magnet synchronous motor at time k .

[0133] The current detection module 402 is configured to obtain dq-axis current feedback values of the permanent magnet synchronous motor at time k .

[0134] The speed-current controller 403 is configured to execute the speed prediction control method of the permanent magnet synchronous motor in the above embodiments based on the given value of the mechanical angular velocity at time k , the mechanical angular velocity feedback value and the dq-axis current feedback value , and output dq-axis voltage given values at time k+1 ; specifically, the given value of the mechanical angular velocity of the permanent magnet synchronous motor at time k , the mechanical angular velocity feedback value and the feedback value of the dq-axis current are input into the speed-current controller 403, and the speed-current controller 403 outputs the dq-axis voltage given value at time k+1 .

[0135] The inverter 404 is configured to perform space vector pulse width modulation on the dq-axis voltage given value at time k+1 , generate a switching signal and send it to the inverter, and the switching signal is used to control the inverter to output a corresponding voltage to act on the permanent magnet synchronous motor, so as to control the current and speed of the permanent magnet synchronous motor at time k+2.

[0136] Specifically, the position detection module 401 can be a position sensor, and the current detection module 402 can be a current sensor.

[0137] As shown in Figure 5As shown, for example, the given value of the mechanical angular velocity of the permanent magnet synchronous motor at time k is sampled during the k-th control cycle. Mechanical angular velocity feedback value and dq axis current feedback value As the input to the speed-current controller; the speed-current controller first uses the current prediction equation based on the dq-axis current feedback value at time k. Calculate the estimated dq-axis current at time k+1. Secondly, the torque prediction equation is used based on the dq-axis current feedback value at time k. The estimated dq-axis current at time k+1 Calculate the estimated electromagnetic torque at time k. Estimated electromagnetic torque at time k+1 Then, the rotational speed prediction equation and the disturbance estimation equation are used based on the mechanical angular velocity feedback value at time k. Calculate the estimated mechanical angular velocity at time k+1. The lumped disturbance estimate at time k+1 Next, the torque setpoint calculation equation is used based on the mechanical angular velocity setpoint at time k. Calculate the electromagnetic torque setpoint at time k+2. Then, the current-given calculation equation is used based on the electromagnetic torque given at time k+2. Calculate the dq-axis current setpoint at time k. Finally, the voltage-given calculation equation is used based on the dq-axis current given at time k. Calculate the dq-axis voltage setpoint at time k+1. .

[0138] Among them, the given value of the mechanical angular velocity of the motor This can be sent from the preceding controller or preset. Estimated value of stator resistance. Estimated values ​​of dq axis inductance and Estimated value of permanent magnet flux Estimated value of moment of inertia All of these can be obtained in advance through offline methods. The mechanical angular position of the motor rotor at time k. The mechanical angular velocity feedback value at time k is obtained through sampling by the position sensor. By measuring the mechanical angle position The feedback values ​​of electrical angular position and electrical angular velocity are obtained by multiplying the corresponding feedback values ​​of mechanical angular position and mechanical angular velocity by the number of pole pairs p; the dq-axis current feedback value at time k. Stator three-phase current is monitored by current sensors After sampling, the electrical angle position of the rotor at time k is combined After coordinate transformation from the stationary three-phase coordinate system to the rotating two-phase coordinate system, the following is obtained.

[0139] In one embodiment, as shown in Figure 6 , a speed prediction control system of a permanent magnet synchronous motor is provided, which includes a permanent magnet synchronous motor and a speed prediction control device in the above embodiment, and the speed prediction control device is used to control the operation of the permanent magnet synchronous motor.

[0140] For example, the current sensor is used to sample the three-phase stator current of the surface-mounted or built-in permanent magnet synchronous motor at time k ; the position sensor is used to sample the mechanical angle position of the rotor of the motor at time k ; the speed-current controller is used to calculate and output the dq-axis voltage given value at time k+1 , with the given value of the mechanical angular velocity of the permanent magnet synchronous motor at time k , the mechanical angular velocity feedback value and the dq-axis current feedback value as input; the space vector pulse width modulator is used to modulate and generate the corresponding switching signal according to the dq-axis voltage given value of the motor ; and the inverter is used to output the corresponding voltage to act on the permanent magnet synchronous motor under the control of the switching signal.

[0141] The technical features of the above embodiments can be combined in any way. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0142] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent of the present application. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A method of speed predictive control of a permanent magnet synchronous motor, characterized in that, The method comprises: Obtain the mechanical angular velocity setpoint of the permanent magnet synchronous motor at time k. Mechanical angular velocity feedback value and dq axis current feedback value ; by the dq-axis current feedback value at the kth instant and a current prediction equation to determine a dq-axis current estimation value at the (k+1)th instant , and by the dq-axis current estimation value at the (k+1)th instant and a torque prediction equation to determine an electromagnetic torque estimation value at the (k+1)th instant ; by the mechanical angular velocity feedback value at the k time and a rotational speed prediction equation to determine a mechanical angular velocity estimation value at the k+1 time by the mechanical angular velocity feedback value at the k time and a disturbance estimation equation to determine a lumped disturbance estimation value at the k+1 time ; by said k instant mechanical angular speed given value , said k+1 instant lumped disturbance estimation value , said k+1 instant mechanical angular speed estimation value , said k+1 instant electromagnetic torque estimation value and a torque given calculation equation, determining a k+2 instant electromagnetic torque given value ; by said electromagnetic torque given value at instant k+2 and current given calculation equation, determining dq-axis current given value at instant k ; by said dq-axis current given value at instant k , said dq-axis current estimation value at instant k+1 , determining dq-axis voltage given value at instant k+1 ; the dq-axis voltage value given at the k+1 moment performing space vector pulse width modulation to generate a switching signal and sending the switching signal to the inverter, the switching signal being used to control the inverter to output a corresponding voltage to act on the permanent magnet synchronous motor, so as to control the current and the rotating speed of the permanent magnet synchronous motor at the k+2 moment.

2. The speed predictive control method of a permanent magnet synchronous motor according to claim 1, characterized by, by the dq-axis current feedback value at the kth instant and a current prediction equation to determine a dq-axis current estimation value at the (k+1)th instant , and by the dq-axis current estimation value at the (k+1)th instant and a torque prediction equation to determine an electromagnetic torque estimation value at the (k+1)th instant , comprising: The current prediction equation is the sum of a first part and a second part, the first part being related to the dq-axis current feedback value at time k The second part being related to the dq-axis voltage given value at time k The dq-axis current feedback value at time k The dq-axis voltage given value at time k Is substituted into the current prediction equation to obtain the dq-axis current estimation value at time k+1 The first part is The second part is , , , , represents the estimated value of the stator resistance, represents the estimated value of the d-axis inductance, represents the estimated value of the q-axis inductance, represents the estimated value of the permanent magnet flux linkage, represents the control period, represents the electrical angular velocity feedback value at time k; the dq-axis current feedback value at the kth instant the electromagnetic torque estimate at the kth instant is obtained by substituting the dq-axis current estimate at the kth instant the electromagnetic torque estimate at the k+1th instant is obtained by substituting the dq-axis current estimate at the k+1th instant the electromagnetic torque estimate at the kth instant is obtained by substituting the dq-axis current estimate at the kth instant the electromagnetic torque estimate at the k+1th instant is obtained by substituting the dq-axis current estimate at the k+1th instant 3. The speed predictive control method of a permanent magnet synchronous motor according to claim 2, characterized by, by the mechanical angular velocity feedback value at the k time and a rotational speed prediction equation to determine a mechanical angular velocity estimation value at the k+1 time by the mechanical angular velocity feedback value at the k time and a disturbance estimation equation to determine a lumped disturbance estimation value at the k+1 time comprising: a sum of an electromagnetic torque estimation value at a k+1 time point and a target torque difference defined as a difference between a target torque and an electromagnetic torque estimation value at a k time point a difference between a mechanical angular velocity estimation value at a k time point and a target angular velocity difference defined as a difference between a target angular velocity and a mechanical angular velocity feedback value at a k time point the target angular velocity difference; wherein the speed prediction equation and the disturbance estimation equation are both based on a discretized mathematical model of a mechanical part of a permanent magnet synchronous motor and an extended state observer, the discretized mathematical model of the mechanical part of the permanent magnet synchronous motor being constructed based on a super-local model;​​ the target torque and the target angular velocity difference, the lumped disturbance estimate value at time k the mechanical angular velocity estimate value at time k substituting into the rotational speed prediction equation to obtain the mechanical angular velocity estimate value at time k+1 ; the target angular velocity difference and the lumped disturbance estimate value at the k time point substituting into the disturbance estimation equation, the lumped disturbance estimate value at the k+1 time point is obtained .

4. The speed predictive control method of a permanent magnet synchronous motor according to claim 1, characterized by, The equation left side of the torque command calculation equation is an electromagnetic torque command value at a k+2 time The equation right side of the torque command calculation equation includes a first expression and a second expression; the first expression includes a mechanical angular velocity command value at the k time , a lumped disturbance estimation value at the k+1 time , and a mechanical angular velocity estimation value at the k+1 time The second expression includes an electromagnetic torque estimation value at the k+1 time The electromagnetic torque command value at the k+2 time in the torque command calculation equation is equal to the first expression minus the second expression; The first expression is The second expression is , represents an estimated value of the moment of inertia, represents a control period.

5. The speed predictive control method of a permanent magnet synchronous motor according to claim 1, characterized by, The determination mode of the torque given calculation equation comprises: Taking the speed dynamic response time of three control periods as a control target; the electromagnetic torque estimation value at the instant k+3 the lumped disturbance estimation value at the instant k+1 the balance, and the mechanical angular velocity estimation value at the instant k+3 equal to the mechanical angular velocity given value at the instant k , obtaining the torque given calculation equation.

6. The speed predictive control method of a permanent magnet synchronous motor according to claim 5, characterized by, the electromagnetic torque estimate at the instant k+3 the lumped disturbance estimate at the instant k+1 the balance, and the mechanical angular velocity estimate at the instant k+3 equal to the mechanical angular velocity given value at the instant k , obtaining the torque given calculation equation, comprising: an estimate of the electromagnetic torque at time k+3 a lumped disturbance estimate at time k+1 a first relationship between an estimate of the electromagnetic torque at time k+3 a lumped disturbance estimate at time k+1 the first relationship is , denotes an estimate of the moment of inertia the k+3th moment is estimated by the action of electromagnetic torque in the k+1th and k+2th control periods the given value of the mechanical angular velocity at the kth moment , the k+3th moment is estimated by the action of electromagnetic torque in the k+1th and k+2th control periods the k+2th moment is estimated by the action of electromagnetic torque in the k+1th and k+2th control periods the k+1th moment is estimated by the action of electromagnetic torque in the k+1th and k+2th control periods the second relationship between the k+2th moment is estimated by the action of electromagnetic torque in the k+1th and k+2th control periods , denotes the control period; based on the first relationship, the second relationship, the mechanical angular velocity estimation value at the k+3 time equal to the mechanical angular velocity given value at the k time , and the electromagnetic torque estimation value at the k+2 time equal to the electromagnetic torque given at the k+2 time , the torque given calculation equation is obtained.

7. The speed predictive control method of a permanent magnet synchronous motor according to claim 1, characterized by, by said electromagnetic torque given value at said instant k+2 and current given calculation equation, determining the dq axis current given value at instant k comprising: Determining a relationship expression of the electromagnetic torque given value and the dq-axis current given value, substituting the expression of the dq-axis current given value into the relationship expression to obtain a target equation of the electromagnetic torque given value and the q-axis current given value; by the electromagnetic torque given value at the k+2 moment obtaining an initial value of the target equation iteration ; iteratively solving the target equation by using Newton-Raphson iteration method to obtain the current given calculation equation, and determining the dq-axis current given value at the k moment based on the current given calculation equation . 8.The method of claim 1, wherein by the dq-axis current given value at the k time , the dq-axis current estimated value at the k+1 time , determining the dq-axis voltage given value at the k+1 time , comprising: obtaining a mechanical angular velocity estimation value at time k+1 ; based on the mechanical angular velocity estimate at the k+1 time , determine an electrical angular velocity estimate at the k+1 time ; the dq-axis current given value at the k+1 time , the dq-axis current estimated value at the k+1 time , and the electrical angular velocity estimated value at the k+1 time , into the voltage given calculation equation to obtain the dq-axis voltage given value at the k+1 time .

9. A speed predictive control device of a permanent magnet synchronous motor, characterized by, The device comprises a speed-current controller, an inverter, a current detection module and a position detection module; The position detection module is configured to acquire a mechanical angular velocity feedback value of the permanent magnet synchronous motor at time k ; The current detection module is configured to acquire dq-axis current feedback values of the permanent magnet synchronous motor at time k ; The rotational speed-current controller is configured to give a mechanical angular speed value at time k based on the mechanical angular speed feedback value , the mechanical angular speed feedback value , and the dq-axis current feedback value The rotational speed prediction control method of the permanent magnet synchronous motor according to any one of claims 1 to 8 is executed, and a dq-axis voltage given value at time k+1 is output ; The inverter is configured to give a dq-axis voltage value at the k+1 time point The space vector pulse width modulation is performed to generate a switching signal and send it to the inverter, and the switching signal is used to control the inverter to output a corresponding voltage acting on the permanent magnet synchronous motor, so as to control the current and the rotating speed of the permanent magnet synchronous motor at the k+2 time point.

10. A speed predictive control system of a permanent magnet synchronous motor, characterized by, The system comprises a permanent magnet synchronous motor and the speed prediction control device in claim 9, and the speed prediction control device is used for controlling the permanent magnet synchronous motor to operate.

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