A method for controlling the rotating speed of a permanent magnet synchronous motor and related device

Abstract

This invention discloses a speed control method and related device for a permanent magnet synchronous motor (PMSM), relating to the field of motors. By constructing an improved motion equation for the PMSM and extending the mechanical angular velocity, total load torque of the speed loop, and their derivatives as new state variables, an augmented state variable observation equation is constructed. This enables real-time estimation of the mechanical angular velocity, total load torque of the speed loop, and their derivatives at the current moment. Based on these estimates, the predicted value of the total load torque of the speed loop at future moments is predicted, and the predicted value of the electromagnetic torque at future moments is determined accordingly. This predicted electromagnetic torque is then used as the reference torque for the current loop at the current moment and output in advance. Since the predicted electromagnetic torque corresponds to the torque required at future moments, outputting it in advance compensates for the delay of the entire control link, ensuring that the inverter output voltage matches the future system state, thereby effectively solving the problem of speed loop response lag.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, and more specifically, to a method and related apparatus for controlling the speed of a permanent magnet synchronous motor. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) have been widely used in automotive drives, aerospace, and robotics due to their superior salient pole characteristics, high reluctance torque, and high power density.

[0003] However, in the speed control system of permanent magnet synchronous motor, due to factors such as sensor sampling delay and inverter output delay, the controller output lags behind the changes in the system current state, resulting in a lag in the speed loop control response of the permanent magnet synchronous motor, which cannot meet the actual engineering requirements for speed loop control performance. Summary of the Invention

[0004] In view of this, the present invention discloses a speed control method and related device for a permanent magnet synchronous motor, in order to solve the problem of speed loop response lag caused by sensor sampling delay and inverter output delay, and to meet the requirements of actual engineering for speed loop control performance.

[0005] A method for controlling the speed of a permanent magnet synchronous motor, comprising:

[0006] Based on the initial motion equations, changes in the body parameters, and disturbances of the permanent magnet synchronous motor, an improved motion equation for the permanent magnet synchronous motor is constructed.

[0007] Based on the improved motion equation of the permanent magnet synchronous motor, the mechanical angular velocity, the total load torque of the speed loop and their derivatives are added as new state variables, resulting in the augmented state variable observation equation.

[0008] Solving the augmented state variable observation equation yields the estimated values ​​of the total load torque of the speed loop, the estimated value of the mechanical angular velocity, and the estimated values ​​of the derivatives of the total load torque of the speed loop at the current moment.

[0009] Based on the estimated total load torque of the speed loop, the estimated mechanical angular velocity, and the estimated derivatives of the total load torque of the speed loop, the predicted value of the total load torque of the speed loop at future times is predicted.

[0010] The predicted electromagnetic torque value for future times is determined based on the predicted total load torque value of the speed loop, and the predicted electromagnetic torque value is used as the reference torque of the current loop at the current time to control the speed of the permanent magnet synchronous motor.

[0011] Optionally, based on the improved motion equations of the permanent magnet synchronous motor, the mechanical angular velocity, the total load torque of the speed loop, and their derivatives are used as new state variables to obtain the augmented state variable observation equations, which specifically include:

[0012] The improved motion equations of the permanent magnet synchronous motor are augmented by taking the mechanical angular velocity, the total load torque of the speed loop and its derivatives as new state variables, to obtain the augmented motion equations of the permanent magnet synchronous motor.

[0013] The mechanical angular velocity in the augmented form of the permanent magnet synchronous motor's motion equations is processed by feedback closed-loop processing to obtain the augmented state variable observation equations.

[0014] Optionally, the mechanical angular velocity in the augmented form of the permanent magnet synchronous motor's equation of motion is subjected to feedback closed-loop processing to obtain the augmented state variable observation equation, specifically including:

[0015] Subtracting the augmented motion equation of the permanent magnet synchronous motor from the augmented state variable observation equation yields the augmented state variable error equation, which is used to characterize the dynamic error relationship between the observed and actual values ​​of the augmented state variable observation equation.

[0016] Based on the augmented state variable error equation, the eigenvalues ​​of the observation error matrix in the augmented state variable error equation are all made to have negative real parts, so as to perform feedback closed-loop correction on the augmented state variable observation equation.

[0017] Optionally, the eigenvalues ​​of the observation error matrix in the augmented state variable error equation are all made to have negative real parts, specifically including:

[0018] The observation bandwidth of the augmented state variable observation equation is set to a positive value;

[0019] Configure the observation coefficient matrix of the augmented state variable observation equation according to the observation bandwidth, so that the eigenvalues ​​of the observation error matrix are all negative observation bandwidth values.

[0020] Optionally, based on the estimated total load torque of the speed loop, the estimated mechanical angular velocity, and the estimated derivatives of the total load torque of the speed loop, the predicted value of the total load torque of the speed loop at future times is predicted, specifically including:

[0021] Based on the estimated derivatives of the total load torque of the speed loop at the current moment, a prediction equation for the total load torque of the speed loop of the permanent magnet synchronous motor is constructed.

[0022] Substituting the current estimated value of the total load torque of the speed loop, the estimated value of the mechanical angular velocity, and the estimated values ​​of the derivatives of the total load torque of the speed loop into the prediction equation of the total load torque of the speed loop, the predicted value of the total load torque of the speed loop at future times is obtained.

[0023] Optionally, based on the predicted total load torque of the speed loop, a predicted electromagnetic torque value for future times is determined, and this predicted electromagnetic torque value is used as the reference torque of the current loop at the current time to control the speed of the permanent magnet synchronous motor. Specifically, this includes:

[0024] Set the mechanical angular velocity at a future moment to track the commanded rotational speed as the first condition;

[0025] The second condition is that the rate of change of mechanical angular velocity at a future time is equal to the rate of change of mechanical angular velocity at the next time after the current time.

[0026] Based on the improved motion equation of the permanent magnet synchronous motor, the first condition, and the second condition, the predicted value of the electromagnetic torque at future times is calculated.

[0027] The predicted electromagnetic torque is used as the reference torque of the current loop at the current moment to control the speed of the permanent magnet synchronous motor.

[0028] Optionally, based on the initial equations of motion of the permanent magnet synchronous motor, the changes in its body parameters, and the disturbances, an improved equations of motion for the permanent magnet synchronous motor are constructed, specifically including:

[0029] The initial motion equations of the permanent magnet synchronous motor are obtained, which include electromagnetic torque, load torque, mechanical angular velocity, actual moment of inertia, and actual damping coefficient.

[0030] By introducing the nominal moment of inertia and the change of the actual moment of inertia relative to the nominal moment of inertia, and adding the actual disturbance in the motion system of the permanent magnet synchronous motor to the initial motion equation of the permanent magnet synchronous motor, the intermediate motion equation of the permanent magnet synchronous motor is obtained.

[0031] By performing a mathematical transformation on the intermediate motion equations of the permanent magnet synchronous motor, the disturbance quantity and the load torque are combined into the total load torque of the speed loop, resulting in the improved motion equations of the permanent magnet synchronous motor.

[0032] A speed control device for a permanent magnet synchronous motor, comprising:

[0033] An improved motion equation construction unit is used to construct an improved motion equation for a permanent magnet synchronous motor based on the initial motion equation, changes in the motor's body parameters, and actual disturbances.

[0034] The observation equation determination unit is used to improve the motion equation based on the permanent magnet synchronous motor, and to take the mechanical angular velocity, the total load torque of the speed loop and its derivative values ​​as new state variables to obtain the augmented state variable observation equation.

[0035] The solution unit is used to solve the augmented state variable observation equation to obtain the estimated values ​​of the total load torque of the speed loop, the estimated values ​​of the mechanical angular velocity, and the estimated values ​​of the derivatives of the total load torque of the speed loop at the current moment.

[0036] The torque prediction value determination unit is used to predict the total load torque of the speed loop at future times based on the estimated value of the total load torque of the speed loop, the estimated value of the mechanical angular velocity, and the estimated values ​​of the derivatives of the total load torque of the speed loop.

[0037] The speed control unit is used to determine the predicted electromagnetic torque value at a future time based on the predicted total load torque value of the speed loop, and to use the predicted electromagnetic torque value as the reference torque of the current loop at the current time to control the speed of the permanent magnet synchronous motor.

[0038] A computer storage medium storing at least one instruction, which, when executed by a processor, implements the aforementioned permanent magnet synchronous motor speed control method.

[0039] A permanent magnet synchronous motor control system includes:

[0040] Motor controller and memory;

[0041] The memory is used to store computer programs;

[0042] The motor controller is used to run the computer program to implement the permanent magnet synchronous motor speed control method described above.

[0043] As can be seen from the above technical solution, this invention discloses a method and related device for controlling the speed of a permanent magnet synchronous motor. By constructing an improved motion equation for the permanent magnet synchronous motor and extending the mechanical angular velocity, total load torque of the speed loop, and their derivatives into new state variables, an augmented state variable observation equation is constructed. This enables real-time estimation of the mechanical angular velocity, total load torque of the speed loop, and their derivatives at the current moment. Based on these estimates, the predicted value of the total load torque of the speed loop at future moments is predicted, and the predicted value of the electromagnetic torque at future moments is determined accordingly. This predicted value of the electromagnetic torque at future moments is then used as the reference torque for the current loop at the current moment and output in advance. Since the predicted electromagnetic torque corresponds to the torque required at future moments, it is equivalent to issuing the control command, which was originally delayed, at the current moment. This pre-compensates for the delay in the entire control link from sensor sampling to inverter output, ensuring that the actual output voltage of the inverter matches the system state at future moments. This effectively solves the problem of speed loop response lag caused by sensor sampling delay and inverter output delay, thereby improving the dynamic response speed and control accuracy of the speed loop and meeting the requirements of practical engineering for speed loop control performance. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the published drawings without creative effort.

[0045] Figure 1 This is a dual-loop control diagram of a permanent magnet synchronous motor disclosed in an embodiment of the present invention;

[0046] Figure 2 This is a flowchart of a permanent magnet synchronous motor speed control method disclosed in an embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram of the structure of a permanent magnet synchronous motor speed control device disclosed in an embodiment of the present invention;

[0048] Figure 4 This is a schematic diagram of a permanent magnet synchronous motor control system disclosed in an embodiment of the present invention. Detailed Implementation

[0049] like Figure 1 The diagram shown illustrates the dual-loop control of a permanent magnet synchronous motor. The speed loop control of the permanent magnet synchronous motor mainly consists of a dual closed-loop cascaded structure comprising an outer loop speed control and an inner loop torque control, as detailed below:

[0050] In the outer loop speed control, the reference speed is compared with the actual feedback speed of the permanent magnet synchronous motor, and the speed controller outputs the reference torque based on the deviation between the two.

[0051] In the inner-loop torque control, the reference torque is used as the input command of the torque controller. The torque controller generates a control signal based on the command and the current feedback from the motor. This control signal drives the permanent magnet synchronous motor to run via the inverter.

[0052] The actual speed output of the permanent magnet synchronous motor is fed back to the outer loop speed control, forming a speed closed loop; the actual current during the operation of the permanent magnet synchronous motor is fed back to the inner loop torque control, forming a current closed loop.

[0053] In the speed control system of permanent magnet synchronous motor, due to factors such as sensor sampling delay, signal filtering delay, inverter output delay, and the inherent zero-order hold hysteresis of digital control, the voltage command output by the controller cannot follow the changes in the system current state in real time. This causes the tracking response of the current loop to lag behind the dynamic changes of the rotor, which in turn limits the bandwidth of the speed loop, reduces the dynamic response speed, and delays the torque response. Ultimately, this affects the fast tracking performance and anti-disturbance capability of the speed loop, making it difficult to meet the engineering requirements of high dynamic performance application scenarios (such as electric vehicle drive, servo system, etc.) for speed loop control response speed and control accuracy.

[0054] To address the aforementioned problems, this invention discloses a method and related apparatus for controlling the speed of a permanent magnet synchronous motor (PMSM). By constructing an improved motion equation for the PMSM and extending the mechanical angular velocity, total load torque of the speed loop, and their derivatives as new state variables, an augmented state variable observation equation is constructed. This enables real-time estimation of the current mechanical angular velocity, total load torque of the speed loop, and their derivatives. Based on these estimates, the predicted total load torque of the speed loop at future moments is predicted, and the predicted electromagnetic torque at those future moments is determined accordingly. This predicted electromagnetic torque is then used as the reference torque for the current loop at the current moment and output in advance. Since the predicted electromagnetic torque corresponds to the torque required at future moments, it is equivalent to issuing the control command, which would otherwise be delayed, at the current moment. This pre-compensates for the delay in the entire control link from sensor sampling to inverter output, ensuring that the actual output voltage of the inverter matches the system state at future moments. This effectively solves the problem of speed loop response lag caused by sensor sampling delay and inverter output delay, thereby improving the dynamic response speed and control accuracy of the speed loop and meeting the performance requirements of speed loop control in practical engineering.

[0055] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] To address the issue of delayed speed loop control response in permanent magnet synchronous motors (PMSMs) caused by controller output lagging behind changes in system current state due to factors such as sensor sampling delay and inverter output delay, this invention improves the initial motion equations of the PMSMs as follows:

[0057] Typically, the initial equation of motion for a permanent magnet synchronous motor can be expressed as:

[0058] (1);

[0059] In the formula, The mechanical angular velocity of the permanent magnet synchronous motor; This is the actual moment of inertia. For electromagnetic torque, For load torque, This is the actual damping coefficient.

[0060] During their research, the inventors discovered that as the operating time and conditions of the permanent magnet synchronous motor change, the motor's inherent parameters, such as moment of inertia, also change. and damping coefficient All of these will change. However, the initial motion equation of the permanent magnet synchronous motor shown in formula (1) does not show the disturbances that actually exist in the motion system of the permanent magnet synchronous motor and are difficult to model.

[0061] Based on this, the present invention proposes a more accurate intermediate motion equation for the permanent magnet synchronous motor, as shown in equation (2):

[0062] (2);

[0063] In the formula, This is the nominal moment of inertia value of the permanent magnet synchronous motor; Actual moment of inertia The change in moment of inertia relative to the nominal value, and satisfying , For the identifier of the change; This refers to the actual disturbance quantity existing in the motion system of the permanent magnet synchronous motor.

[0064] By performing a mathematical transformation on equation (2), we obtain the improved motion equation of the permanent magnet synchronous motor, as shown in equation (3):

[0065] (3);

[0066] In the formula, This represents the total load torque of the speed loop of the permanent magnet synchronous motor. The total load torque of the speed loop includes disturbance information and satisfies... .

[0067] The improved motion equations of the permanent magnet synchronous motor are augmented by taking the mechanical angular velocity, the total load torque of the speed loop, and their derivatives as new state variables, resulting in the augmented motion equations of the permanent magnet synchronous motor, as shown in formula (4):

[0068] (4);

[0069] In the formula, express The first derivative value; express The value of the second derivative; express The (n-1)th order derivative value; express The nth-order derivative value, where n represents the order. This indicates an augmented variable.

[0070] The mechanical angular velocity is calculated from the augmented form of the motion equation of the permanent magnet synchronous motor shown in formula (4). Feedback closed-loop processing yields the augmented state variable observation equations, which include the speed loop and the total load torque. and mechanical angular velocity The expression is shown in formula (5):

[0071] (5);

[0072] In the formula, This represents the estimated mechanical angular velocity of a permanent magnet synchronous motor. This represents the estimated total load torque of the speed loop of the permanent magnet synchronous motor. This represents the estimated value of the augmented variable. express The estimated value; express The estimated value; express The estimated value; express The estimated value; express The estimated value; express The estimated value; Represents the observation coefficient matrix, , , , , ..., , These are the observation coefficients.

[0073] Subtracting the augmented motion equation of the permanent magnet synchronous motor shown in formula (4) from the augmented state variable observation equation shown in formula (5), we obtain the augmented state variable error equation, as shown in formula (6):

[0074] (6);

[0075] In the formula, This represents the estimation error matrix between the actual and estimated values ​​of the speed loop total load torque and mechanical angular velocity observation system for a permanent magnet synchronous motor. This represents the observation error matrix.

[0076] To ensure the accuracy of the observation of the total load torque and mechanical angular velocity of the speed loop of the permanent magnet synchronous motor, the estimation error matrix between the actual and estimated values ​​of the mechanical angular velocity observation system is crucial. Asymptotic stability approaches zero; using the theory of linear system stability, it is only necessary to adjust the observation error matrix. The eigenvalues ​​all have negative real parts.

[0077] Assume the observation bandwidth of the augmented state variable observation equation shown in formula (5) is , If the numbers are positive, we can obtain the observation coefficient matrix. The latest expression is shown below:

[0078] ;

[0079] Then the observation error matrix can be realized. The eigenvalues ​​are all This theoretically ensures accurate estimation of the total load torque, mechanical angular velocity, and derivatives of the total load torque of the permanent magnet synchronous motor, where n represents the order.

[0080] observation coefficient matrix Substituting the latest expression into the augmented state variable observation equation shown in formula (5), we can obtain the solution. Estimated total load torque of the permanent magnet synchronous motor at a given time. ,as well as The speed of the permanent magnet synchronous motor at any given time, the total load torque Estimates of the derivatives of each order. Simultaneously, we can also obtain... Estimated mechanical angular velocity at time t .

[0081] according to The speed of the permanent magnet synchronous motor at any given time, the total load torque The estimated values ​​of each order derivative are obtained. The prediction equation for the total load torque of the speed loop of the permanent magnet synchronous motor at time t is shown in equation (7):

[0082] (7);

[0083] In the formula, express At any given moment, the rotational speed and the total load torque are all constant. The estimated value, i.e. Estimated total load torque of the rotational speed loop at any given time;

[0084] express At any given moment, the rotational speed and the total load torque are all constant. The estimated value, i.e. Estimated total load torque of the rotational speed loop at any given time;

[0085] express At any given moment, the rotational speed and the total load torque are all constant. The estimated value, i.e. Estimated total load torque of the rotational speed loop at any given time;

[0086] express At any given moment, the rotational speed and the total load torque are all constant. The estimated value, i.e. Estimated total load torque of the rotational speed loop at any given time. It is a positive integer greater than or equal to 1;

[0087] Indicates the speed loop control period;

[0088] Indicates the total load torque of the speed ring. The estimated value of the first derivative;

[0089] Indicates the total load torque of the speed ring. The second derivative value The estimated value;

[0090] Indicates the total load torque of the speed ring. The (i-1)th derivative value The estimated value;

[0091] Indicates the total load torque of the speed ring. The (i)th derivative value The estimated value, It is a positive integer greater than or equal to 1.

[0092] Substitute the augmented variable estimate obtained by solving formula (5) into formula (7) to obtain the predicted value of the total load torque of the speed loop of the permanent magnet synchronous motor.

[0093] Assuming the speed loop of the permanent magnet synchronous motor is in The mechanical angular velocity at any given time can track the commanded rotational speed value, that is:

[0094] (8);

[0095] In the formula, express The mechanical angular velocity at a given moment. It is a positive integer greater than or equal to 1. express The commanded rotational speed value at that moment.

[0096] To ensure the smoothness of the speed loop control of the permanent magnet synchronous motor, this invention assumes... The rate of change of mechanical angular velocity at any moment and When the rate of change of mechanical angular velocity is constant, we obtain the equation shown in formula (9):

[0097] (9);

[0098] Based on formulas (3), (8), and (9), and ignoring estimation errors, it is assumed that... Formula (10) can be obtained. Electromagnetic torque prediction equation at time:

[0099] (10);

[0100] In the formula, This means that the formula (7) is used to calculate the result. Estimated total load torque of the rotational speed loop at any given time. express The predicted value of the electromagnetic torque at time t, i.e. Electromagnetic torque at all times Step-by-step predicted value.

[0101] Will Electromagnetic torque prediction value at time 1 As The reference torque of the constant current loop is used to control the speed of the permanent magnet synchronous motor.

[0102] In summary, this invention effectively solves the problem of lag in the speed loop control response of permanent magnet synchronous motors caused by sensor sampling delay and inverter output delay. Furthermore, by performing real-time online compensation for disturbances, this invention further improves the adaptability of the speed control strategy to different operating conditions and reduces its dependence on motor parameters, thereby avoiding the drawback of requiring repeated calibration during motor operation.

[0103] Based on the above theoretical innovations, this invention discloses a method for controlling the speed of a permanent magnet synchronous motor, which is applied to a permanent magnet synchronous motor control system.

[0104] See Figure 2 The present invention discloses a flowchart of a speed control method for a permanent magnet synchronous motor, the method comprising:

[0105] Step S101: Based on the initial motion equation of the permanent magnet synchronous motor, the changes in the main body parameters, and the disturbance, construct the improved motion equation of the permanent magnet synchronous motor.

[0106] In this embodiment, the initial motion equation of the permanent magnet synchronous motor is shown in formula (1). During the research process, the inventors discovered that as the operating time and operating conditions of the permanent magnet synchronous motor change, the motor's inherent parameters, such as moment of inertia, change. and damping coefficient All of these will change. Furthermore, the initial motion equation of the permanent magnet synchronous motor shown in formula (1) does not show the disturbances that actually exist in the motion system of the permanent magnet synchronous motor and are difficult to model.

[0107] Based on this, the present invention adds the change of body parameters and the disturbance amount to the initial motion equation of the permanent magnet synchronous motor, and obtains the improved motion equation of the permanent magnet synchronous motor shown in formula (3).

[0108] Specifically, the initial motion equations of the permanent magnet synchronous motor are obtained, as shown in formula (1). The initial motion equations of the permanent magnet synchronous motor include electromagnetic torque. Load torque Mechanical angular velocity Actual moment of inertia and actual damping coefficient .

[0109] Introducing nominal moment of inertia and actual moment of inertia Relative to the nominal moment of inertia Change And the disturbances that actually exist in the motion system of the permanent magnet synchronous motor are added to the initial motion equation of the permanent magnet synchronous motor to obtain the intermediate motion equation of the permanent magnet synchronous motor, as shown in formula (2).

[0110] The intermediate motion equation of the permanent magnet synchronous motor is mathematically transformed, and the disturbance quantity and the load torque are combined into the total load torque of the speed loop to obtain the improved motion equation of the permanent magnet synchronous motor, as shown in formula (3).

[0111] Step S102: Based on the improved motion equation of the permanent magnet synchronous motor, the mechanical angular velocity, the total load torque of the speed loop and its derivatives are added as new state variables to obtain the augmented state variable observation equation.

[0112] This embodiment constructs an augmented state variable observation equation by adding mechanical angular velocity, total load torque of the speed loop, and their derivatives as new state variables. Its core function is to transform the originally difficult-to-measure total load torque into an observable quantity, while simultaneously acquiring its derivative information, providing a data foundation for subsequent predictions. Through augmentation processing, the actual change in moment of inertia and unmodeled disturbances in the system are unified into the total load torque, making the observation equation rely only on the nominal moment of inertia without requiring precise time-varying parameters. This reduces the dependence on motor physical parameters and improves the operating condition adaptability of the control strategy.

[0113] Step S103: Solve the augmented state variable observation equation to obtain the estimated values ​​of the total load torque of the speed loop, the estimated value of the mechanical angular velocity, and the estimated values ​​of the derivatives of the total load torque of the speed loop at the current moment.

[0114] It should be noted that the current time in this application is referred to as... Time indicates.

[0115] Assume the observation bandwidth of the augmented state variable observation equation shown in formula (5) is , If the numbers are positive, we can obtain the observation coefficient matrix. The latest expression is shown below:

[0116] ;

[0117] Then the observation error matrix can be realized. The eigenvalues ​​are all .

[0118] Through the observation coefficient matrix Substituting the latest expression into the augmented state variable observation equation shown in formula (5), we can obtain the solution. Estimated total load torque of the permanent magnet synchronous motor at a given time. Mechanical angular velocity estimate as well as The speed of the permanent magnet synchronous motor at any given time, the total load torque Estimates of the derivatives of each order.

[0119] Step S104: Based on the estimated total load torque of the speed loop, the estimated mechanical angular velocity, and the estimated derivatives of the total load torque of the speed loop, predict the predicted total load torque of the speed loop at future times.

[0120] Specifically, based on the estimated values ​​of the derivatives of the total load torque of the speed loop at the current moment, the prediction equation for the total load torque of the speed loop of the permanent magnet synchronous motor is constructed, as shown in formula (7).

[0121] Estimate the total load torque of the rotational speed ring at the current moment. The estimated mechanical angular velocity Substituting the estimated values ​​of the derivatives of the total load torque of the speed loop into the prediction equation of the total load torque of the speed loop, we obtain the predicted values ​​of the total load torque of the speed loop at future times.

[0122] In this embodiment, the augmented variable estimate obtained by solving formula (5) includes: the mechanical angular velocity estimate of the permanent magnet synchronous motor. Estimated total load torque of the speed loop of a permanent magnet synchronous motor The estimated values ​​of the derivatives of the total load torque of the speed loop are obtained by substituting the augmented variable estimates obtained by solving formula (5) into the prediction equation of the total load torque of the speed loop shown in formula (7), and the predicted values ​​of the total load torque of the speed loop at future times can be obtained.

[0123] This embodiment utilizes the estimated total load torque of the speed loop, the estimated mechanical angular velocity, and the estimated derivatives of the total load torque of the speed loop at the current moment to construct a predictive equation for the total load torque of the speed loop. This allows for the prediction of the future trend of the total load torque of the speed loop, extending the estimation of the total load torque from the current moment to the future moment. This enables the system to anticipate disturbance changes before the delay occurs, providing an accurate basis for the calculation of the subsequent electromagnetic torque prediction value and laying a data foundation for subsequent compensation control.

[0124] Step S105: Determine the predicted electromagnetic torque value for future times based on the predicted total load torque value of the speed loop, and use the predicted electromagnetic torque value as the reference torque of the current loop at the current time to control the speed of the permanent magnet synchronous motor.

[0125] Specifically, the mechanical angular velocity at a future moment is set to track the commanded rotational speed as the first condition, i.e., formula (8).

[0126] Assume that the rate of change of mechanical angular velocity at a future time is equal to the rate of change of mechanical angular velocity at the next time after the current time, as the second condition, i.e., formula (9).

[0127] Based on the improved motion equation of the permanent magnet synchronous motor, the first condition, and the second condition, the predicted value of the electromagnetic torque at future times is calculated.

[0128] The predicted electromagnetic torque is used as the reference torque of the current loop at the current moment to control the speed of the permanent magnet synchronous motor.

[0129] This embodiment improves the motion equation of the permanent magnet synchronous motor according to formula (3), formula (8), and formula (9), while ignoring the estimation error, that is, it is considered that... Formula (10) can be obtained. The electromagnetic torque prediction equation at time t is obtained by solving it. The predicted electromagnetic torque value at time t is used as... The reference torque of the constant current loop is used to control the speed of the permanent magnet synchronous motor.

[0130] In summary, this invention discloses a speed control method for a permanent magnet synchronous motor. By constructing an improved motion equation for the permanent magnet synchronous motor and extending the mechanical angular velocity, total load torque of the speed loop, and their derivatives as new state variables, an augmented state variable observation equation is constructed. This enables real-time estimation of the mechanical angular velocity, total load torque of the speed loop, and their derivatives at the current moment. Based on these estimates, the predicted value of the total load torque of the speed loop at future moments is predicted, and the predicted value of the electromagnetic torque at future moments is determined accordingly. This predicted electromagnetic torque is then used as the reference torque for the current loop at the current moment and output in advance. Since the predicted electromagnetic torque corresponds to the torque required at future moments, it is equivalent to issuing the control command, which would otherwise be delayed, at the current moment. This pre-compensates for the delay in the entire control link from sensor sampling to inverter output, ensuring that the actual output voltage of the inverter matches the system state at future moments. This effectively solves the problem of speed loop response lag caused by sensor sampling delay and inverter output delay, thereby improving the dynamic response speed and control accuracy of the speed loop and meeting the performance requirements of speed loop control in practical engineering.

[0131] In one embodiment, step S102 may specifically include:

[0132] (1) The improved motion equation of the permanent magnet synchronous motor is augmented by taking the mechanical angular velocity, the total load torque of the speed loop and its derivative values ​​as new state variables to obtain the augmented motion equation of the permanent magnet synchronous motor.

[0133] By augmenting the improved motion equations of the permanent magnet synchronous motor, the actual change in moment of inertia and the unmodeled disturbances of the system are unified into the total load torque. This makes the improved motion equations of the permanent magnet synchronous motor rely only on the nominal moment of inertia without the need for precise time-varying parameters, thereby reducing the dependence on the physical parameters of the motor, improving the adaptability of the control strategy to the operating conditions, and effectively avoiding the drawback of repeated calibration during the use of the motor.

[0134] The augmented form of the motion equations for the permanent magnet synchronous motor can be found in formula (4).

[0135] (2) The mechanical angular velocity in the augmented form of the permanent magnet synchronous motor motion equation is processed by feedback closed loop to obtain the augmented state variable observation equation.

[0136] In this embodiment, the augmented state variable observation equation includes the total load torque of the speed loop. and mechanical angular velocity The expression is shown in formula (5).

[0137] Specifically, by subtracting the augmented form motion equation of the permanent magnet synchronous motor shown in formula (4) from the augmented state variable observation equation shown in formula (5), the augmented state variable error equation shown in formula (6) is obtained. The augmented state variable error equation is used to characterize the error dynamic relationship between the observed value and the actual value of the augmented state variable observation equation.

[0138] According to the augmented state variable error equation shown in formula (6), the eigenvalues ​​of the observation error matrix in the augmented state variable error equation are all negative real parts, so as to perform feedback closed-loop correction on the augmented state variable observation equation.

[0139] This embodiment obtains the augmented state variable error equation by subtracting the augmented form motion equation of the permanent magnet synchronous motor from the augmented state variable observation equation. Then, by using the linear system stability theory, the eigenvalues ​​of the observation error matrix are configured to all have negative real parts, so that the estimation error matrix between the actual value and the estimated value of the observation system asymptotically stabilizes and approaches zero. Theoretically, this ensures the accurate estimation of the total load torque and mechanical angular velocity of the speed loop of the permanent magnet synchronous motor, providing accurate disturbance information for subsequent prediction and control.

[0140] Specifically, ensuring that all eigenvalues ​​of the observation error matrix in the augmented state variable error equation have negative real parts includes:

[0141] The observation bandwidth of the augmented state variable observation equation is set to a positive value;

[0142] Configure the observation coefficient matrix of the augmented state variable observation equation according to the observation bandwidth, so that the eigenvalues ​​of the observation error matrix are all negative observation bandwidth values.

[0143] This embodiment sets the observation bandwidth to a positive value and configures the observation coefficient matrix of the augmented state variable observation equation according to the observation bandwidth, so that the eigenvalues ​​of the observation error matrix are all negative observation bandwidth values. Thus, only the observation bandwidth parameter needs to be adjusted to complete the unified configuration of all coefficients of the augmented state variable observation equation. This simplifies the multi-parameter tuning to single-parameter tuning, reduces the difficulty of parameter configuration of the augmented state variable observation equation, and improves the debugging efficiency in engineering applications.

[0144] Corresponding to the above method embodiments, the present invention discloses a speed control device for a permanent magnet synchronous motor.

[0145] See Figure 3 A schematic diagram of the permanent magnet synchronous motor speed control device disclosed in this embodiment of the invention. The device includes:

[0146] The improved motion equation construction unit 201 is used to construct the improved motion equation of the permanent magnet synchronous motor based on the initial motion equation of the permanent magnet synchronous motor, the changes in the body parameters, and the actual disturbances.

[0147] In this embodiment, the initial motion equation of the permanent magnet synchronous motor is shown in formula (1). During the research process, the inventors discovered that as the operating time and operating conditions of the permanent magnet synchronous motor change, the motor's inherent parameters, such as moment of inertia, change. and damping coefficient All of these will change. Furthermore, the initial motion equation of the permanent magnet synchronous motor shown in formula (1) does not show the disturbances that actually exist in the motion system of the permanent magnet synchronous motor and are difficult to model.

[0148] Based on this, the present invention adds the change of body parameters and the disturbance amount to the initial motion equation of the permanent magnet synchronous motor, and obtains the improved motion equation of the permanent magnet synchronous motor shown in formula (3).

[0149] The improved equation of motion building unit 201 is specifically used for:

[0150] The initial motion equations of the permanent magnet synchronous motor are obtained as shown in formula (1). The initial motion equations of the permanent magnet synchronous motor include electromagnetic torque. Load torque Mechanical angular velocity Actual moment of inertia and actual damping coefficient .

[0151] Introducing nominal moment of inertia and actual moment of inertia Relative to the nominal moment of inertia Change And the disturbances that actually exist in the motion system of the permanent magnet synchronous motor are added to the initial motion equation of the permanent magnet synchronous motor to obtain the intermediate motion equation of the permanent magnet synchronous motor, as shown in formula (2).

[0152] The intermediate motion equation of the permanent magnet synchronous motor is mathematically transformed, and the disturbance quantity and the load torque are combined into the total load torque of the speed loop to obtain the improved motion equation of the permanent magnet synchronous motor, as shown in formula (3).

[0153] The observation equation determination unit 202 is used to improve the motion equation based on the permanent magnet synchronous motor, and to add mechanical angular velocity, total load torque of the speed loop and its derivative values ​​as new state variables to obtain the augmented state variable observation equation.

[0154] This embodiment constructs an augmented state variable observation equation by adding mechanical angular velocity, total load torque of the speed loop, and their derivatives as new state variables. Its core function is to transform the originally difficult-to-measure total load torque into an observable quantity, while simultaneously acquiring its derivative information, providing a data foundation for subsequent predictions. Through augmentation processing, the actual change in moment of inertia and unmodeled disturbances in the system are unified into the total load torque, making the observation equation rely only on the nominal moment of inertia without requiring precise time-varying parameters. This reduces the dependence on motor physical parameters and improves the operating condition adaptability of the control strategy.

[0155] The solution unit 203 is used to solve the augmented state variable observation equation to obtain the estimated values ​​of the total load torque of the speed loop, the estimated values ​​of the mechanical angular velocity, and the estimated values ​​of the derivatives of the total load torque of the speed loop at the current moment.

[0156] Assume the observation bandwidth of the augmented state variable observation equation shown in formula (5) is , If the numbers are positive, we can obtain the observation coefficient matrix. The latest expression is shown below:

[0157] ;

[0158] Then the observation error matrix can be realized. The eigenvalues ​​are all .

[0159] Through the observation coefficient matrix Substituting the latest expression into the augmented state variable observation equation shown in formula (5), we can obtain the solution. Estimated total load torque of the permanent magnet synchronous motor at a given time. Mechanical angular velocity estimate as well as The speed of the permanent magnet synchronous motor at any given time, the total load torque Estimates of the derivatives of each order.

[0160] The torque prediction value determination unit 204 is used to predict the total load torque of the speed loop at future times based on the estimated value of the total load torque of the speed loop, the estimated value of the mechanical angular velocity, and the estimated values ​​of the derivatives of the total load torque of the speed loop.

[0161] This embodiment utilizes the estimated total load torque of the speed loop, the estimated mechanical angular velocity, and the estimated derivatives of the total load torque of the speed loop at the current moment to construct a predictive equation for the total load torque of the speed loop. This allows for the prediction of the future trend of the total load torque of the speed loop, extending the estimation of the total load torque from the current moment to the future moment. This enables the system to anticipate disturbance changes before the delay occurs, providing an accurate basis for the calculation of the subsequent electromagnetic torque prediction value and laying a data foundation for subsequent compensation control.

[0162] The speed control unit 205 is used to determine the predicted electromagnetic torque value at a future time based on the predicted total load torque value of the speed loop, and use the predicted electromagnetic torque value as the reference torque of the current loop at the current time to control the speed of the permanent magnet synchronous motor.

[0163] In summary, this invention discloses a speed control transpose for a permanent magnet synchronous motor. By constructing an improved motion equation for the permanent magnet synchronous motor and extending the mechanical angular velocity, total load torque of the speed loop, and their derivatives as new state variables, an augmented state variable observation equation is constructed. This enables real-time estimation of the mechanical angular velocity, total load torque of the speed loop, and their derivatives at the current moment. Based on these estimates, the predicted value of the total load torque of the speed loop at future moments is predicted, and the predicted value of the electromagnetic torque at future moments is determined accordingly. This predicted electromagnetic torque is then used as the reference torque for the current loop at the current moment and output in advance. Since the predicted electromagnetic torque corresponds to the torque required at future moments, it is equivalent to issuing the control command, which would otherwise be delayed, at the current moment. This pre-compensates for the delay in the entire control link from sensor sampling to inverter output, ensuring that the actual output voltage of the inverter matches the system state at future moments. This effectively solves the problem of speed loop response lag caused by sensor sampling delay and inverter output delay, thereby improving the dynamic response speed and control accuracy of the speed loop and meeting the performance requirements of speed loop control in practical engineering.

[0164] In one embodiment, the observation equation determination unit 202 can be specifically used for:

[0165] The improved motion equations of the permanent magnet synchronous motor are augmented by taking the mechanical angular velocity, the total load torque of the speed loop and its derivatives as new state variables, to obtain the augmented motion equations of the permanent magnet synchronous motor.

[0166] The mechanical angular velocity in the augmented form of the permanent magnet synchronous motor's motion equations is processed by feedback closed-loop processing to obtain the augmented state variable observation equations.

[0167] In one embodiment, the observation equation determination unit 202 can also be used for:

[0168] Subtracting the augmented motion equation of the permanent magnet synchronous motor from the augmented state variable observation equation yields the augmented state variable error equation, which is used to characterize the dynamic error relationship between the observed and actual values ​​of the augmented state variable observation equation.

[0169] Based on the augmented state variable error equation, the eigenvalues ​​of the observation error matrix in the augmented state variable error equation are all made to have negative real parts, so as to perform feedback closed-loop correction on the augmented state variable observation equation.

[0170] In one embodiment, the observation equation determination unit 202 can also be used for:

[0171] The observation bandwidth of the augmented state variable observation equation is set to a positive value;

[0172] Configure the observation coefficient matrix of the augmented state variable observation equation according to the observation bandwidth, so that the eigenvalues ​​of the observation error matrix are all negative observation bandwidth values.

[0173] In one embodiment, the torque prediction value determination unit 204 can be specifically used for:

[0174] Based on the estimated derivatives of the total load torque of the speed loop at the current moment, a prediction equation for the total load torque of the speed loop of the permanent magnet synchronous motor is constructed.

[0175] Substituting the current estimated value of the total load torque of the speed loop, the estimated value of the mechanical angular velocity, and the estimated values ​​of the derivatives of the total load torque of the speed loop into the prediction equation of the total load torque of the speed loop, the predicted value of the total load torque of the speed loop at future times is obtained.

[0176] In one embodiment, the speed control unit 205 can be specifically used for:

[0177] Set the mechanical angular velocity at a future moment to track the commanded rotational speed as the first condition;

[0178] The second condition is that the rate of change of mechanical angular velocity at a future time is equal to the rate of change of mechanical angular velocity at the next time after the current time.

[0179] Based on the improved motion equation of the permanent magnet synchronous motor, the first condition, and the second condition, the predicted value of the electromagnetic torque at future times is calculated.

[0180] The predicted electromagnetic torque is used as the reference torque of the current loop at the current moment to control the speed of the permanent magnet synchronous motor.

[0181] It should be noted that for the specific working principles of each component in the device embodiment, please refer to the corresponding section of the method embodiment, which will not be repeated here.

[0182] Corresponding to the above embodiments, the present invention also discloses a computer storage medium that stores at least one instruction, which, when executed by a processor, implements the steps shown in the embodiments of the permanent magnet synchronous motor speed control method.

[0183] Corresponding to the above embodiments, such as Figure 4 As shown, the present invention also provides a structural schematic diagram of a permanent magnet synchronous motor control system, which may include: a motor controller 1 and a memory 2;

[0184] Among them, the motor controller 1 and the memory 2 communicate with each other through the communication bus 3;

[0185] Motor controller 1 is used to execute at least one instruction;

[0186] Memory 2 is used to store at least one instruction;

[0187] The motor controller 1 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention.

[0188] Memory 2 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0189] The processor executes at least one instruction to implement the steps shown in the embodiment of the permanent magnet synchronous motor speed control method.

[0190] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0191] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0192] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of controlling the rotational speed of a permanent magnet synchronous motor, characterized by, include: Based on the initial motion equations, changes in the body parameters, and disturbances of the permanent magnet synchronous motor, an improved motion equation for the permanent magnet synchronous motor is constructed. Based on the improved motion equation of the permanent magnet synchronous motor, the mechanical angular velocity, the total load torque of the speed loop and their derivatives are added as new state variables, resulting in the augmented state variable observation equation. Solving the augmented state variable observation equation yields the estimated values ​​of the total load torque of the speed loop, the estimated value of the mechanical angular velocity, and the estimated values ​​of the derivatives of the total load torque of the speed loop at the current moment. Based on the estimated total load torque of the speed loop, the estimated mechanical angular velocity, and the estimated derivatives of the total load torque of the speed loop, the predicted value of the total load torque of the speed loop at future times is predicted. Based on the predicted total load torque of the speed loop, the predicted electromagnetic torque value for future moments is determined, and the predicted electromagnetic torque value is used as the reference torque of the current loop at the current moment to control the speed of the permanent magnet synchronous motor.

2. The method of claim 1, wherein, Based on the improved motion equations of the permanent magnet synchronous motor, the mechanical angular velocity, the total load torque of the speed loop, and their derivatives are added as new state variables, resulting in the augmented state variable observation equations, which specifically include: The improved motion equations of the permanent magnet synchronous motor are augmented by taking the mechanical angular velocity, the total load torque of the speed loop and its derivatives as new state variables, to obtain the augmented motion equations of the permanent magnet synchronous motor. The mechanical angular velocity in the augmented form of the permanent magnet synchronous motor's motion equations is processed by feedback closed-loop processing to obtain the augmented state variable observation equations.

3. The method of claim 2, wherein, The mechanical angular velocity in the augmented form of the permanent magnet synchronous motor's motion equations is processed by feedback closed-loop processing to obtain the augmented state variable observation equations, specifically including: Subtracting the augmented motion equation of the permanent magnet synchronous motor from the augmented state variable observation equation yields the augmented state variable error equation, which is used to characterize the dynamic error relationship between the observed and actual values ​​of the augmented state variable observation equation. Based on the augmented state variable error equation, the eigenvalues ​​of the observation error matrix in the augmented state variable error equation are all made to have negative real parts, so as to perform feedback closed-loop correction on the augmented state variable observation equation.

4. The method of claim 3, wherein, Let all eigenvalues ​​of the observation error matrix in the augmented state variable error equation have negative real parts, specifically including: The observation bandwidth of the augmented state variable observation equation is set to a positive value; Configure the observation coefficient matrix of the augmented state variable observation equation according to the observation bandwidth, so that the eigenvalues ​​of the observation error matrix are all negative observation bandwidth values.

5. The method of claim 1 to 4, wherein Based on the estimated total load torque of the speed loop, the estimated mechanical angular velocity, and the estimated derivatives of the total load torque of the speed loop, the predicted value of the total load torque of the speed loop at future times is predicted, specifically including: Based on the estimated derivatives of the total load torque of the speed loop at the current moment, a prediction equation for the total load torque of the speed loop of the permanent magnet synchronous motor is constructed. Substituting the current estimated value of the total load torque of the speed loop, the estimated value of the mechanical angular velocity, and the estimated values ​​of the derivatives of the total load torque of the speed loop into the prediction equation of the total load torque of the speed loop, the predicted value of the total load torque of the speed loop at future times is obtained.

6. The method of claim 1 to 4, wherein Based on the predicted total load torque of the speed loop, the predicted electromagnetic torque value for future times is determined, and this predicted electromagnetic torque value is used as the reference torque of the current loop at the current time to control the speed of the permanent magnet synchronous motor. Specifically, this includes: Set the mechanical angular velocity at a future moment to track the commanded rotational speed as the first condition; The second condition is that the rate of change of mechanical angular velocity at a future time is equal to the rate of change of mechanical angular velocity at the next time after the current time. Based on the improved motion equation of the permanent magnet synchronous motor, the first condition, and the second condition, the predicted value of the electromagnetic torque at future times is calculated. The predicted electromagnetic torque is used as the reference torque of the current loop at the current moment to control the speed of the permanent magnet synchronous motor.

7. The method of claim 1, wherein, Based on the initial equations of motion, changes in the motor's parameters, and disturbances, an improved equations of motion for the permanent magnet synchronous motor are constructed, specifically including: The initial motion equations of the permanent magnet synchronous motor are obtained, which include electromagnetic torque, load torque, mechanical angular velocity, actual moment of inertia, and actual damping coefficient. By introducing the nominal moment of inertia and the change of the actual moment of inertia relative to the nominal moment of inertia, and adding the actual disturbance in the motion system of the permanent magnet synchronous motor to the initial motion equation of the permanent magnet synchronous motor, the intermediate motion equation of the permanent magnet synchronous motor is obtained. By performing a mathematical transformation on the intermediate motion equations of the permanent magnet synchronous motor, the disturbance quantity and the load torque are combined into the total load torque of the speed loop, resulting in the improved motion equations of the permanent magnet synchronous motor.

8. A permanent magnet synchronous motor rotation speed control device characterized by comprising: include: An improved motion equation construction unit is used to construct an improved motion equation for a permanent magnet synchronous motor based on the initial motion equation, changes in the motor's body parameters, and actual disturbances. The observation equation determination unit is used to improve the motion equation based on the permanent magnet synchronous motor, and to take the mechanical angular velocity, the total load torque of the speed loop and its derivative values ​​as new state variables to obtain the augmented state variable observation equation. The solution unit is used to solve the augmented state variable observation equation to obtain the estimated values ​​of the total load torque of the speed loop, the estimated values ​​of the mechanical angular velocity, and the estimated values ​​of the derivatives of the total load torque of the speed loop at the current moment. The torque prediction value determination unit is used to predict the total load torque of the speed loop at future times based on the estimated value of the total load torque of the speed loop, the estimated value of the mechanical angular velocity, and the estimated values ​​of the derivatives of the total load torque of the speed loop. The speed control unit is used to determine the predicted electromagnetic torque value at a future time based on the predicted total load torque value of the speed loop, and to use the predicted electromagnetic torque value as the reference torque of the current loop at the current time to control the speed of the permanent magnet synchronous motor.

9. A computer storage medium, characterized in that, The computer storage medium stores at least one instruction, which, when executed by the processor, implements the permanent magnet synchronous motor speed control method as described in any one of claims 1 to 7.

10. A permanent magnet synchronous motor control system, characterized in that, include: Motor controller and memory; The memory is used to store computer programs; The motor controller is used to run the computer program to implement the permanent magnet synchronous motor speed control method according to any one of claims 1 to 7.

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