A gain scheduling intelligent closed-loop control method based on permanent magnet synchronous motor

Abstract

The application discloses a gain scheduling intelligent closed-loop control method based on a permanent magnet synchronous motor, wherein under different working conditions, the gain and error accumulation can be intelligently controlled. The control structure can guarantee the independence of the speed instruction input to the output and the interference input to the output, so that the system has better reference trajectory tracking and interference suppression capability. In order to obtain the best control performance when the parameters are uncertain, a gain scheduling closed-loop control system is used in the advanced pre-input system. Compared with the controller without the controller, the steady-state error is smaller and the dynamic response is better under the condition of external load torque interference and permanent magnet synchronous motor parameter uncertainty.

Description

Technical Field

[0001] This invention belongs to the field of permanent magnet synchronous motor control, and specifically relates to a gain scheduling intelligent closed-loop control method based on permanent magnet synchronous motor. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) possess many excellent characteristics, such as light weight and high steady-state torque density. Due to these advantages, PMSMs are widely used in industrial fields, particularly in high-performance mechatronics applications such as robotics and machine tools. However, the automatic control technology for PMSMs faces some challenges, such as unavoidable interference.

[0003] Linear control systems, such as PI controllers, struggle to function properly under uncertain external load torque and parameters. However, nonlinear control systems exhibit superior performance, such as robust control, predictive control with lead input, stepwise control, and sliding mode control. Lead input compensation can effectively improve the response performance of existing industrial systems.

[0004] Several systematic pre-input controller design methods have been proposed, each with its unique advantages, such as pulsating torque decoupling methods and dead-time compensation methods. Based on a permanent magnet synchronous motor model, a pre-input controller has been designed. An adaptive pre-input controller with a load observer has been proposed, which can estimate the load torque and mechanical parameters, as demonstrated by simulation and experimental results. However, it may not have good response capabilities when the load torque changes abruptly. A closed-loop speed controller with a pre-input control structure has also been proposed, which relies entirely on the estimated parameters; unsatisfactory estimation results can cause the control system to lose control. Subsequently, a pre-input load torque compensator and a PI speed controller have been proposed, showing good performance under varying load torque. However, in systems with significant structural uncertainties, it may not achieve good performance. Summary of the Invention

[0005] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the present invention provides a gain scheduling intelligent closed-loop control method based on permanent magnet synchronous motor, which improves the speed stability performance of the system, reduces steady-state error, enhances robustness, and improves dynamic response.

[0006] Technical solution: To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A gain-scheduled intelligent closed-loop control method based on a permanent magnet synchronous motor includes the following steps:

[0008] Step 1: Establish a permanent magnet synchronous motor model.

[0009] Formulas (1) and (2) are mathematical models of permanent magnet synchronous motors.

[0010] (1)

[0011] (2)

[0012] In the formula: and These are the d-axis and q-axis voltages, respectively. It is the d-axis inductance. It is a q-axis inductor. and These are the D-axis and Q-axis currents, respectively. It is the stator resistance. It is electric angular velocity. It is a magnetic flux generated by a permanent magnet.

[0013] The torque formula for a permanent magnet synchronous motor can be written as formula (3).

[0014] (3)

[0015] The equation of motion for the machine is:

[0016] (4)

[0017] In the formula: It is the moment of inertia. It is the mechanical angular velocity of the permanent magnet synchronous motor. It is the damping coefficient. It is the load torque.

[0018] Using a surface-mounted permanent magnet synchronous motor, the inductance value L of the d-axis d The inductance value L equal to the q-axis q Formula (3) can be written as follows:

[0019] (5)

[0020] In the formula: It is the number of pole pairs of a permanent magnet synchronous motor.

[0021] Q-axis current command i q * It can be written as follows:

[0022] (6)

[0023] e(t) is the velocity deviation, e(t) = ω ref -ω m ;K p (t), K i(t) represents the gain coefficient and the error accumulation coefficient, respectively.

[0024] The control voltage of the dq axis is calculated using formulas (1) and (2). First, the speed command ω is... ref By using the input-lead pre-input system, ω can be obtained through its calculations. qf ω qf As the speed advance pre-input command for the control system, the speed command ω ref and feedback speed value ω m The deviation value between the input gain scheduling closed-loop control system can be written as formula (7):

[0025] (7)

[0026] It is the gain coefficient of the speed controller loop, k i It is the error accumulation coefficient of the speed controller loop. It is the time required for one sampling cycle.

[0027] Step 2: The advance input control method for permanent magnet synchronous motors includes sub-step A and sub-step B.

[0028] Sub-step A. Design of current loop advance input.

[0029] The formula for calculating the q-axis current is as follows, which can be obtained from formula (2).

[0030] (8)

[0031] It is the q-axis voltage value. It is the voltage across the resistor. It is mutual voltage. It is the magnetic flux linkage voltage; according to formula (9).

[0032] (9)

[0033] R FF The resistor is used to calculate the current command that is ahead of the pre-input current in the current loop; The magnetic flux generated by the permanent magnet is obtained to calculate the current command that is ahead of the current loop input. This is used to input the advance speed command.

[0034] use As an input advance pre-input current command It is the q-axis voltage that is ahead of the input, which can be written as formula (10).

[0035] (10)

[0036] In formula (10), , , L FF These are the error accumulation coefficient, gain coefficient, current command, and speed advance input inductor in the advance input circuit, respectively.

[0037] Sub-step B. Design of the speed loop advance input.

[0038] Use i FF As a pre-input current command, it can be written as formula (11):

[0039] (11)

[0040] , , , These are the error accumulation coefficient, gain coefficient, motor torque coefficient, and moment of inertia in the speed loop, respectively. , calculated by formula (12).

[0041] (12)

[0042] According to formulas (9)-(12), It can be written as formula (13).

[0043] (13)

[0044] Equation (13) can be written as equation (14).

[0045] (14)

[0046] Define the function according to equation (13). , Equation (15) is given.

[0047] (15)

[0048] Equation (15) can be written as equation (16).

[0049] (16)

[0050] Assumption , , , , These are the ideal parameters of a permanent magnet synchronous motor: torque coefficient, inductance, stator resistance, rotor flux linkage, and moment of inertia. , which satisfies formula (17).

[0051] (17)

[0052] , These are the cumulative error value and the gain value; the same control structure is used in feedback systems and lead-input systems. It can be written as formula (18).

[0053] (18)

[0054] , These are the ideal cumulative error and gain values ​​in the feedback system; formula (19) is adjusted by... This will satisfy the following equation.

[0055] (19)

[0056] According to formulas (17)-(19), the speed command ω ref and feedback speed value ω m The transfer function between them is shown in formula (20).

[0057] (20)

[0058] Step 3: Gain scheduling intelligent closed-loop control method.

[0059] The gain scheduling value is adjusted through exponential calculation, which makes speed deviation compensation fast.

[0060] (twenty one)

[0061] In formula (21), , These are the gain value and error accumulation value for the next control cycle. , These are the maximum and minimum gain values; , These are the maximum and minimum cumulative error values; It is the speed command value for the kth cycle. It is a speed command and feedback speed value Deviation between; It can be written as formula (22), which determines / The rate of change between the maximum and minimum values ​​is given by the following formula.

[0062] (twenty two)

[0063] when When the value is large, The value of is increased to speed up the transient response.

[0064] when When the value is small, The value of decreases and is used to eliminate overshoot and oscillation.

[0065] when When the value is large, The value decreases to eliminate oscillations and overshoot.

[0066] when When the value is small, The value of increases to overcome steady-state error.

[0067] but and The value is based on the deviation value The transfer function of the gain scheduling intelligent closed-loop control method for permanent magnet synchronous motors is obtained by varying between the maximum and minimum values.

[0068] (twenty three)

[0069] Beneficial effects: This invention has the following advantages:

[0070] 1. A forward input system is proposed. This control structure can ensure the independence of speed command input to output and disturbance input to output, so that the system has better reference trajectory tracking and disturbance suppression capabilities.

[0071] 2. A gain scheduling closed-loop algorithm is proposed, which can achieve smaller steady-state error and better dynamic response compared with a controller without this controller, under the conditions of external load torque disturbance and uncertainty of permanent magnet synchronous motor parameters. Attached Figure Description

[0072] Appendix Figure 1 This is a schematic diagram of the permanent magnet synchronous motor control system in this invention;

[0073] Appendix Figure 2 This is a block diagram of the permanent magnet synchronous motor drive system in this invention;

[0074] Appendix Figure 3 This is a block diagram of the advanced input control system current in this invention;

[0075] Appendix Figure 4 This is a block diagram of the gain scheduling control in this invention;

[0076] Appendix Figure 5 This is a schematic diagram of the advance input system with gain scheduling control in this invention. Detailed Implementation

[0077] The invention will now be further described with reference to the accompanying drawings.

[0078] As attached Figure 1 To be continued Figure 5 As shown, a gain-scheduled intelligent closed-loop control method based on a permanent magnet synchronous motor is described. The specific implementation process of the method includes the following steps:

[0079] Step 1: Establish a permanent magnet synchronous motor model.

[0080] Formulas (1) and (2) are the mathematical models of permanent magnet synchronous motors:

[0081] (1)

[0082] (2)

[0083] In the formula: and These are the d-axis and q-axis voltages, respectively. It is the d-axis inductance. It is a q-axis inductor. and These are the D-axis and Q-axis currents, respectively. It is the stator resistance. It is electric angular velocity. It is a magnetic flux generated by a permanent magnet.

[0084] The torque formula for a permanent magnet synchronous motor can be written as formula (3).

[0085] (3)

[0086] Equations of motion for machines.

[0087] (4)

[0088] In the formula: It is the moment of inertia. It is the mechanical angular velocity of the permanent magnet synchronous motor. It is the damping coefficient. It is the load torque.

[0089] Using a surface-mounted permanent magnet synchronous motor, the inductance value L of the d-axis d The inductance value L equal to the q-axis q Formula (3) can be written as follows.

[0090] (5)

[0091] In the formula: It is the number of pole pairs of a permanent magnet synchronous motor.

[0092] Q-axis current command It can be written as follows.

[0093] (6)

[0094] e(t) is the velocity deviation, e(t) = ω ref - ω m ;K p (t), K i (t) are the gain coefficient and the error accumulation coefficient, respectively. Then we can obtain the command current value of the q-axis and calculate the control voltage of the dq-axis using formulas (1) and (2).

[0095] As shown in Figure (1), firstly, the speed command ω is... ref Input advance pre-input system. Through the calculations performed by the advance pre-input system, we can obtain ω. qf ω qf As a speed advance pre-input command for the control system As a current advance input command, the speed command ω ref and feedback speed value ω m The deviation value between the input gain is used to control the closed-loop control system. As shown in Figure (2), the speed controller can be written as formula (7).

[0096] (7)

[0097] k v It is the gain coefficient of the speed controller loop, k i It is the error accumulation coefficient of the speed controller loop. It is the time required for one sampling cycle.

[0098] Step 2: Advance input control method for permanent magnet synchronous motors.

[0099] Sub-step A. Design of current loop advance input.

[0100] The formula for calculating the Q-axis current is as follows, which can be obtained from formula (2):

[0101] (8)

[0102] R FF The resistor is used to calculate the current command that is ahead of the pre-input current in the current loop; The magnetic flux generated by the permanent magnet is obtained to calculate the current command that is ahead of the current loop input. This is used to input the advance speed command.

[0103] (9)

[0104] R FF The resistor is used to calculate the current command that is ahead of the pre-input current in the current loop; The magnetic flux generated by the permanent magnet is obtained to calculate the current command that is ahead of the current loop input. This is used to input the advance speed command.

[0105] use As an input advance pre-input current command It is the q-axis voltage that is ahead of the input, which can be written as formula (10).

[0106] (10)

[0107] In formula (10), , , L FF These are the error accumulation coefficient, gain coefficient, current command, and speed advance input inductor in the advance input circuit, respectively.

[0108] Sub-step B. Design of the speed loop advance input. Using i FF As a current command for advance input, it can be written as formula (11).

[0109] (11)

[0110] , , , These are the error accumulation coefficient, gain coefficient, motor torque coefficient, and moment of inertia in the speed loop, respectively. , calculated by formula (12).

[0111] (12)

[0112] As shown in Figure (3), according to formulas (9)-(12), It can be written as formula (13).

[0113] (13)

[0114] Equation (13) can be written as equation (14).

[0115] (14)

[0116] According to equation (13), functions f1 and f2 can be written as equation (15).

[0117] (15)

[0118] Equation (15) can be written as equation (16).

[0119] (16)

[0120] Assumption , , , , These are the ideal parameters of a permanent magnet synchronous motor: torque coefficient, inductance, stator resistance, rotor flux linkage, and moment of inertia. , which satisfies formula (17). (17)

[0121] , These are the cumulative error value and the gain value; the same control structure is used in feedback systems and lead-input systems. It can be written as formula (18).

[0122] (18)

[0123] , These are the ideal cumulative error and gain values ​​in the feedback system; formula (19) is adjusted by... This will satisfy the following equation.

[0124] (19)

[0125] According to formulas (17)-(19), the speed command ω ref and speed feedback value ω m The transfer function between them is shown in formula (20).

[0126] (20)

[0127] Step 3: Gain scheduling intelligent closed-loop control method. As shown in Figure (4), the gain scheduling value can be adjusted by exponential calculation, which makes speed deviation compensation fast.

[0128] (twenty one)

[0129] In formula (21), , These are the gain value and error accumulation value for the next control cycle. , These are the maximum and minimum gain values; , These are the maximum and minimum cumulative error values; It is the speed command value for the kth cycle. It is a speed command and speed feedback value Deviation between; It can be written as formula (22), which determines / The rate of change between the maximum and minimum values ​​is given by the following formula.

[0130] (twenty two)

[0131] when When the value is large, The value of is increased to speed up the transient response.

[0132] when When the value is small, The value of decreases and is used to eliminate overshoot and oscillation.

[0133] when When the value is large, The value decreases to eliminate oscillations and overshoot.

[0134] when When the value is small, The value of increases to overcome steady-state error.

[0135] but and The value is based on the deviation value It varies between the maximum and minimum values.

[0136] As shown in Figure (5), we can finally obtain the transfer function of the gain scheduling intelligent closed-loop control method for permanent magnet synchronous motor.

[0137] (twenty three)

[0138] This invention proposes a gain-scheduled intelligent closed-loop control method based on a permanent magnet synchronous motor (PMSM), which intelligently controls both gain and error accumulation under different operating conditions. The control structure used in the lead-input system is the same as that in the feedback control system. This control structure ensures the independence of speed command input to output from disturbance input to output, giving the system better reference trajectory tracking and disturbance suppression capabilities. To achieve optimal control performance under parameter uncertainty, a gain-scheduled closed-loop control system is used in the lead-input system. Under conditions of external load torque disturbance and uncertain PMSM parameters, the steady-state error is smaller and the dynamic response is better compared to a controller without this controller.

[0139] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A gain-scheduled intelligent closed-loop control method based on a permanent magnet synchronous motor, characterized in that: Includes the following steps: Step 1: Establish a permanent magnet synchronous motor model; Formulas (1) and (2) are the mathematical models of permanent magnet synchronous motors: (1) (2) The torque formula for a permanent magnet synchronous motor is written as formula (3): (3) Equations of motion for machines: (4) Using a surface-mounted permanent magnet synchronous motor, the inductance value L of the d-axis d The inductance value L equal to the q-axis q Formula (3) can be written as follows: (5) Q-axis current command i q * It can be written as follows: (6) e(t) is the velocity deviation, e(t) = ω ref -ω m ;K p (t), K i (t) represent the gain coefficient and the error accumulation coefficient, respectively; The control voltage of the dq axis is calculated using formulas (1) and (2). First, the speed command ω is... ref The input is fed into a lead pre-input system, and ω is obtained through calculations performed by the lead pre-input system. qf ω qf As the speed advance pre-input command for the control system, the speed command ω ref and feedback speed value ω m The deviation value between the input gain scheduling closed-loop control system is written as formula (7): (7) It is the gain coefficient of the speed controller loop, k i It is the error accumulation coefficient of the speed controller loop; Step 2: The advance input control method for permanent magnet synchronous motors, including sub-steps A and B: Sub-step A. Design of current loop advance input: The formula for calculating the q-axis current is as follows, obtained from formula (2): (8) It is the q-axis voltage value. It is the voltage across the resistor. It is mutual voltage. It is the magnetic flux linkage voltage; according to formula (8): (9) use As an input advance pre-input current command It is the q-axis voltage that is ahead of the input, written as formula (10): (10) In formula (10), , , L FF These are the error accumulation coefficient, gain coefficient, current command, and speed advance input inductor in the advance input loop, respectively. Sub-step B. Design of the speed loop advance input: Use i FF As a pre-input current command, it is written as formula (11): (11) , , , These are the error accumulation coefficient, gain coefficient, motor torque coefficient, and moment of inertia in the speed loop, respectively. Calculated using formula (12): (12) According to formulas (9)-(12), Written as formula (13): （13） Equation (13) can be written as equation (14): (14) Define the function according to equation (13). , For equation (15): (15) Equation (15) can be written as equation (16): (16) Assumption , , , , These are the ideal parameters of a permanent magnet synchronous motor: torque coefficient, inductance, stator resistance, rotor flux linkage, and moment of inertia. It satisfies formula (17): (17) , These are the cumulative error value and the gain value; the same control structure is used in feedback systems and lead-input systems. Written as formula (18): (18) , These are the ideal cumulative error and gain values ​​in the feedback system; formula (19) is adjusted by... Then the following equation is satisfied: (19) According to formulas (17)-(19), the speed command ω ref and feedback speed value ω m The transfer function between them is shown in formula (20): (20) Step 3: Gain Scheduling Intelligent Closed-Loop Control Method The gain scheduling value is adjusted through exponential calculation, which makes speed deviation compensation fast; (21) In formula (21), , These are the gain value and error accumulation value for the next control cycle; , These are the maximum and minimum gain values; , These are the maximum and minimum cumulative error values; It is a speed command and feedback speed value Deviation between; Written as formula (22), it determines / The rate of change between the maximum and minimum values ​​is expressed as follows: (22) when When the value is large, The value of is increased to accelerate the transient response; when When the value is small, The value decreases, and it is used to eliminate overshoot and oscillation; when When the value is large, The value decreases to eliminate oscillations and overshoot; when When the value is small, The value of increases to overcome steady-state error; but and The value is based on the deviation value The transfer function of the gain-scheduled intelligent closed-loop control method for permanent magnet synchronous motors, varying between the maximum and minimum values, is as follows: (23)。

Images