A feedforward quadrature phase-locked loop, a permanent magnet synchronous motor speed and rotor position estimation method and system

Abstract

The present invention discloses a feedforward orthogonal phase-locked loop, a method and system for estimating the speed and rotor position of a permanent magnet synchronous motor. The feedforward orthogonal phase-locked loop includes: a phase detector, a PI regulator, a speed calculation module, an integrator, a feedforward loop, and a summation operation. The feedforward loop includes: a feedforward quantity calculation module, a first low-pass filter, a second low-pass filter, and a compensation angle calculation module. The present invention designs a phase detector link that is independent of the rotation direction of the permanent magnet synchronous motor to solve the problem of instability of the traditional orthogonal phase-locked loop under reversing conditions, and designs a feedforward loop to suppress the position DC offset error under the acceleration and deceleration conditions of the motor. The feedforward loop does not require a differential link and can maintain the anti-interference performance of the traditional orthogonal phase-locked loop. At the same time, a small signal model of the feedforward orthogonal phase-locked loop is established, and a parameter design method is provided based on the frequency response characteristics of the system. High-performance operation of the permanent magnet synchronous motor without position sensor control is achieved.

Description

Technical Field

[0001] The present invention belongs to the field of permanent magnet synchronous motor control, and in particular relates to a feedforward orthogonal phase-locked loop, a permanent magnet synchronous motor speed and rotor position estimation method and system. Background Art

[0002] Permanent magnet synchronous motors (PMSMs) have significant advantages, such as simple mechanical structure, compact size, and high power factor, making them widely used in industrial applications across a wide range of power levels. However, the installation of mechanical position sensors increases system cost and size, and reduces system robustness. In some applications, sensorless control techniques must be used, which estimate the speed and rotor position without the use of mechanical position sensors.

[0003] For medium and high speeds, the fundamental frequency model method is typically used to implement sensorless control of permanent magnet synchronous motors. This method uses an observer to estimate back-electromotive force or flux information, and an orthogonal phase-locked loop (PLL) to obtain motor speed and rotor position information. However, under the reversing operation of the permanent magnet synchronous motor, a 180-degree steady-state error exists between the rotor position estimated by the traditional PLL and the actual value, resulting in control failure. Furthermore, zero-error tracking of the rotor position is impossible under acceleration and deceleration conditions, resulting in increased rotor position error. Therefore, the traditional PLL has significant drawbacks in situations where the permanent magnet synchronous motor requires frequent forward and reverse rotation and frequent acceleration and deceleration. Summary of the Invention

[0004] The purpose of the embodiments of the present invention is to provide a feedforward orthogonal phase-locked loop, a permanent magnet synchronous motor speed and rotor position estimation method and system to solve the above technical problems.

[0005] The present invention is achieved according to the following technical solutions:

[0006] In a first aspect, the present invention provides a feedforward orthogonal phase-locked loop, comprising:

[0007] Phase detector, used to identify the relationship between the normalized value of the input back electromotive force and the rotor position;

[0008] PI regulator, used to estimate the electrical angular velocity based on the rotor position quantization signal value output by the phase detector;

[0009] A speed calculation module is used to calculate an estimated value of the permanent magnet synchronous motor speed based on the estimated electrical angular velocity;

[0010] An integrator is used to integrate the estimated electrical angular velocity to obtain an original estimated value of the rotor position;

[0011] A feedforward loop is used to obtain a compensation amount for a DC offset error of the rotor position based on a normalized value of back electromotive force and an original estimated value of the rotor position output by an integrator;

[0012] A summation operation is performed to sum the compensation amount of the rotor position DC offset error and the output of the integrator to obtain an estimated value of the permanent magnet synchronous motor rotor position.

[0013] In one embodiment, the rotor position quantization signal value output by the phase detector is:

[0014]

[0015] Among them, Δe is the quantized signal value of the rotor position, is the raw estimate of the rotor position.

[0016] In one embodiment, the feedforward loop includes:

[0017] A feedforward calculation module is used to calculate the feedforward amount based on the normalized value of the back electromotive force and the original value of the rotor position output by the integrator;

[0018] Low-pass filter 1, used for filtering high-frequency components in the rotor position quantization signal value output by the integrator;

[0019] Low-pass filter 2, used to filter the high-frequency components in the feedforward output by the feedforward calculation module;

[0020] The compensation angle calculation module is used to calculate the compensation amount of the position DC offset error based on the sine component of the compensation amount output by the low-pass filter 1 and the cosine component of the compensation amount output by the low-pass filter 2.

[0021] The second invention provides a method for estimating the speed and rotor position of a permanent magnet synchronous motor. The method is based on the above-mentioned feedforward orthogonal phase-locked loop and comprises:

[0022] Obtain the stator current and stator voltage of the permanent magnet synchronous motor in a two-phase stationary coordinate system;

[0023] Estimation of back electromotive force of stator current and stator voltage of permanent magnet synchronous motor in two-phase stationary coordinate system;

[0024] Perform back electromotive force normalization on the back electromotive force estimation value;

[0025] Perform parameter tuning on the feedforward quadrature phase-locked loop;

[0026] The normalized value is input into the feedforward orthogonal phase-locked loop after parameter tuning to obtain the estimated value of the permanent magnet synchronous motor rotor position and speed.

[0027] In one embodiment, the back electromotive force estimation uses a second-order adaptive super-helical sliding mode observer to estimate the back electromotive force of the permanent magnet synchronous motor. The back electromotive force estimation formula of the permanent magnet synchronous motor is as follows:

[0028]

[0029] Among them, sign is the sign function, when its input is greater than 0, its output is 1, otherwise it is -1; L d , L q are the d-axis and q-axis inductances of the permanent magnet synchronous motor respectively; i α 、i β is the stator current of the permanent magnet synchronous motor, k1 and k2 are gain coefficients; Estimated current for the α-axis, Estimated current for the β axis, To estimate the difference between the α-axis current and the measured value, is the difference between the estimated β-axis current and the measured value.

[0030] In one embodiment, the normalized value of the back EMF estimate is for:

[0031]

[0032] in, are the components of the estimated back electromotive force of the permanent magnet synchronous motor under the α-axis and β-axis of the two-phase stationary coordinate system.

[0033] In one embodiment, the parameter tuning of the feedforward quadrature phase-locked loop specifically includes:

[0034] Establish a small signal model of the feedforward orthogonal phase-locked loop and derive the closed-loop transfer function of the feedforward orthogonal phase-locked loop;

[0035] The open-loop transfer function of the feedforward orthogonal phase-locked loop is deduced from the closed-loop transfer function of the feedforward orthogonal phase-locked loop;

[0036] According to the stability margin of the system, the open-loop transfer function of the feedforward orthogonal phase-locked loop is tuned.

[0037] In one embodiment, the open-loop transfer function of the feedforward orthogonal phase-locked loop is adjusted according to the stability margin of the system, and the open-loop transfer function of the feedforward orthogonal phase-locked loop is adjusted to the following formula:

[0038]

[0039] Among them, K and ω z is an intermediate variable, satisfying the following relationship:

[0040]

[0041] The expression of the phase margin PM of the feedforward orthogonal phase-locked loop is:

[0042]

[0043] Where ω c For the introduced intermediate variable, the expression is:

[0044]

[0045] In one embodiment, the PM is set between 30°-60°, ω c Set to 100-200 rad / s.

[0046] The third invention is to provide a permanent magnet synchronous motor speed and rotor position estimation system based on a feedforward orthogonal phase-locked loop, the system comprising:

[0047] An acquisition module is used to obtain the stator current and stator voltage of the permanent magnet synchronous motor in a two-phase stationary coordinate system;

[0048] Back electromotive force estimation module, used to estimate the back electromotive force of the permanent magnet synchronous motor stator current and stator voltage in a two-phase stationary coordinate system;

[0049] A back electromotive force normalization module is used to perform back electromotive force normalization processing on the back electromotive force estimation value;

[0050] Parameter tuning module, used for tuning parameters of feedforward quadrature phase-locked loop;

[0051] The feedforward quadrature phase-locked loop is used to extract the rotor position estimation value and the speed estimation value of the permanent magnet synchronous motor from the normalized back electromotive force value based on the parameters obtained by using the parameter tuning module.

[0052] Beneficial effects of the present invention:

[0053] This invention designs a phase detector independent of the permanent magnet synchronous motor's rotation direction to address the instability problem of conventional quadrature phase-locked loops (PLLs) under reverse rotation. It also incorporates a feedforward loop that effectively suppresses the DC offset error in rotor position that occurs under acceleration and deceleration. This feedforward loop eliminates the need for a differential element, maintaining the anti-interference performance of conventional PLLs. This achieves high-performance sensorless control of permanent magnet synchronous motors. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The accompanying drawings, as part of this disclosure, are intended to provide a further understanding of the disclosure. The exemplary embodiments of the disclosure and their descriptions are intended to explain the disclosure and do not constitute undue limitations thereon. Obviously, the drawings described below are merely examples, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0055] Figure 1 A structural diagram of a feedforward quadrature phase-locked loop provided by one embodiment of the present invention;

[0056] Figure 2 A flow chart of a method for estimating the speed and rotor position of a permanent magnet synchronous motor provided by one embodiment of the present invention;

[0057] Figure 3 A small signal model diagram of a feedforward quadrature phase-locked loop provided by one embodiment of the present invention;

[0058] Figure 4 A schematic diagram of the structure of a permanent magnet synchronous motor speed and rotor position estimation system based on a feedforward quadrature phase-locked loop according to an embodiment of the present invention;

[0059] Figure 5 (a) is the experimental result of a conventional phase-locked loop in a permanent magnet synchronous motor under forward acceleration conditions according to an embodiment of the present invention. Figure 5 (b)(c)(d) is Figure 5 (a) A partial enlarged view of the actual and estimated rotor positions in a specific area.

[0060] Figure 6 (a) is the experimental result of an embodiment of the present invention using the permanent magnet synchronous motor speed and rotor position estimation system provided by the present invention under the forward acceleration condition of the permanent magnet synchronous motor. Figure 6 (b)(c)(d) is Figure 6 (a) A partial enlarged view of the actual and estimated rotor positions in a specific area.

[0061] Figure 7 The experimental results of a conventional phase-locked loop in a permanent magnet synchronous motor under reverse working conditions according to an embodiment of the present invention are shown;

[0062] Figure 8 (a) is the experimental result of an embodiment of the present invention using the permanent magnet synchronous motor speed and rotor position estimation system provided by the present invention under the reverse deceleration condition of the permanent magnet synchronous motor, Figure 8 (b)(c)(d) is Figure 8 (a) A partial enlarged view of the actual rotor position and the estimated rotor position in a specific area.

[0063] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but rather to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0064] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0065] Figure 1 The present invention provides a structural diagram of a feedforward orthogonal phase-locked loop in one embodiment, which includes a phase detector 3-1, a PI regulator 3-2, an integrator 3-3, a feedforward loop 3-4 and a speed calculation module 3-5.

[0066] Phase detector, used to identify the relationship between the normalized value of the input back electromotive force and the rotor position;

[0067] PI regulator, used to estimate the electrical angular velocity based on the rotor position quantization signal value output by the phase detector;

[0068] A speed calculation module is used to calculate an estimated speed value of the permanent magnet synchronous motor based on the estimated electrical angular velocity;

[0069] An integrator is used to integrate the estimated electrical angular velocity to obtain an original estimated value of the rotor position;

[0070] A feedforward loop is used to obtain a compensation amount for a DC offset error of the rotor position based on a normalized value of back electromotive force and an original estimated value of the rotor position output by an integrator;

[0071] A summation operation is performed to sum the compensation amount of the rotor position DC offset error and the output of the integrator to obtain an estimated value of the permanent magnet synchronous motor rotor position.

[0072] In the embodiment of the present application, the input quantity of the phase detector 3-1 is the normalized value of the electromotive force and the output of integrator 3-3 of the original estimated rotor position Its output is the rotor position quantization signal value Δe, and the calculation formula is as follows:

[0073]

[0074] Among them, Δe is the quantized signal value of the rotor position, is the raw estimate of the rotor position.

[0075] When the permanent magnet synchronous motor rotates forward, the output of the back electromotive force normalization module 2 The expression is as follows:

[0076]

[0077] Among them, θ e is the actual rotor position of the permanent magnet synchronous motor.

[0078] When the permanent magnet synchronous motor reverses, the output of the back electromotive force normalization module 2 The expression is as follows:

[0079]

[0080] The permanent magnet synchronous motor is under forward and reverse working conditions. Substituting the expression into the calculation formula of the phase detector 3-1, the following results can be obtained:

[0081]

[0082] Therefore, the output Δe of the phase detector 3 - 1 is consistent when the permanent magnet synchronous motor rotates forward or reversely, that is, the output of the phase detector is independent of the rotation direction of the permanent magnet synchronous motor.

[0083] As a comparison, the formula used by the phase detector in a traditional orthogonal phase-locked loop to calculate Δe is as follows:

[0084]

[0085] When the permanent magnet synchronous motor rotates forward, the output of the back electromotive force normalization module 2 is Substituting the expression into the calculation formula of the phase detector Δe of the traditional orthogonal phase-locked loop, we can get:

[0086]

[0087] When the permanent magnet synchronous motor reverses, the output of the back electromotive force normalization module 2 is Substituting the expression into the calculation formula of the phase detector Δe of the traditional orthogonal phase-locked loop, we can get:

[0088]

[0089] It can be seen that the output result of the phase detector used in the traditional orthogonal phase-locked loop is related to the rotation direction of the permanent magnet synchronous motor. When the permanent magnet synchronous motor reverses, the rotor position estimated by the traditional orthogonal phase-locked loop will deviate from the actual rotor position by about 180 degrees, resulting in failure of permanent magnet synchronous motor control.

[0090] The feedforward orthogonal phase-locked loop proposed in the present invention can effectively overcome the problem of a 180-degree deviation in the estimated rotor position of a conventional orthogonal phase-locked loop when the permanent magnet synchronous motor reverses.

[0091] Furthermore, the input of the PI regulator 3-2 is the rotor position quantization signal value Δe, and its output is the estimated electrical angular velocity The calculation process in the s domain is as follows:

[0092]

[0093] Among them, k p1 Indicates the proportional coefficient of the PI regulator, k i1 Indicates the integral coefficient of the PI regulator.

[0094] Furthermore, the input of the integrator 3-3 is the estimated electrical angular velocity Its output is the raw estimate of the rotor position The calculation process in the s domain is as follows:

[0095]

[0096] In the embodiment of the present application, the feedforward loop 3-4 includes a feedforward amount calculation module 3-4-1, a low-pass filter 3-4-2, a low-pass filter 3-4-3, and a compensation angle calculation module 3-4-4. The feedforward amount calculation module is used to calculate the feedforward amount based on the normalized value of the back electromotive force and the original value of the rotor position output by the integrator;

[0097] Low-pass filter 1, used for filtering high-frequency components in the rotor position quantization signal value output by the integrator;

[0098] Low-pass filter 2, used to filter the high-frequency components in the feedforward output by the feedforward calculation module;

[0099] The compensation angle calculation module is used to calculate the compensation amount of the position DC offset error based on the sine component of the compensation amount output by the low-pass filter 1 and the cosine component of the compensation amount output by the low-pass filter 2.

[0100] Specifically, the input of the feedforward calculation module 3-4-1 is the normalized value of the back electromotive force The output of integrator 3-3 and the original estimated value of the rotor position Its output is Δe1, and the calculation formula is as follows:

[0101]

[0102] Furthermore, the input of the low-pass filter 3-4-2 is the rotor position quantization signal value Δe output by the phase detector 3-1, and its output is the compensation sinusoidal component y. The calculation process in the s domain is as follows:

[0103]

[0104] Among them, ω Lis the cutoff frequency of the low-pass filter.

[0105] Furthermore, the input of the second low-pass filter 3-4-3 is the output Δe1 of the feedforward calculation module 3-4-1, and its output is the compensation cosine component x. The calculation process in the s domain is as follows:

[0106]

[0107] Furthermore, the input of the compensation angle calculation 3-4-4 is the compensation sine component x and the compensation cosine component y, and its output is the compensation Δθ of the position DC offset error e The calculation process is as follows:

[0108] Δθ e =0.5atan2(y,x)

[0109] Among them, atan2 is the inverse tangent function.

[0110] Furthermore, the compensation angle is calculated as the compensation amount Δθ of the DC offset error of the output position of 3-4-4 e The output of integrator 3-3 and the original estimated value of the rotor position Sum and get the estimated value of the permanent magnet synchronous motor rotor position

[0111] Furthermore, the output of the PI regulator 3-2 After the speed calculation module 3-5, the estimated speed value of the permanent magnet synchronous motor is calculated according to the following formula

[0112]

[0113] Among them, P n is the number of pole pairs of the permanent magnet synchronous motor.

[0114] like Figure 2 As shown, the present invention provides a method for estimating the speed and rotor position of a permanent magnet synchronous motor based on a feedforward orthogonal phase-locked loop, the method comprising:

[0115] S100: Obtaining the stator current and stator voltage of the permanent magnet synchronous motor in a two-phase stationary coordinate system;

[0116] Specifically, the motor stator current i in the two-phase stationary coordinate system is α 、i β The calculation process is as follows:

[0117]

[0118]

[0119] The stator voltage of the permanent magnet synchronous motor is equal to the reference voltage of the SVPWM modulation in vector control.

[0120] S200: Estimating back electromotive force of the stator current and stator voltage of the permanent magnet synchronous motor in a two-phase stationary coordinate system;

[0121] In the embodiment of the present application, the back electromotive force estimation uses a second-order adaptive super-helical sliding mode observer to realize the estimation of the back electromotive force of the permanent magnet synchronous motor. The back electromotive force estimation formula of the permanent magnet synchronous motor is as follows:

[0122]

[0123] Among them, sign is the sign function, when its input is greater than 0, its output is 1, otherwise it is -1; L d , L q are the d-axis and q-axis inductances of the permanent magnet synchronous motor respectively; i α 、i β is the stator current of the permanent magnet synchronous motor, k1 and k2 are gain coefficients; Estimated current for the α-axis, Estimated current for the β axis, To estimate the difference between the α-axis current and the measured value, is the difference between the estimated β-axis current and the measured value.

[0124] and The calculation can be performed according to the following differential equation:

[0125]

[0126] Where, is the estimated value of electrical angular velocity.

[0127] S300: performing back electromotive force normalization processing on the back electromotive force estimation value;

[0128] In the embodiment of the present application, the normalized value of the back electromotive force estimation value is for:

[0129]

[0130] in, are the components of the estimated back electromotive force of the permanent magnet synchronous motor under the α-axis and β-axis of the two-phase stationary coordinate system.

[0131] S400: Parameter tuning of the feedforward quadrature phase-locked loop;

[0132] In the embodiment of the present application, the parameters of the feedforward quadrature phase-locked loop are adjusted, and the specific steps include:

[0133] S410: Establishing a small signal model of a feedforward orthogonal phase-locked loop and deriving a closed-loop transfer function of the feedforward orthogonal phase-locked loop;

[0134] Specifically, a small signal model of the feedforward quadrature phase-locked loop is established, such as Figure 3 As shown, the closed-loop transfer function of the feedforward orthogonal phase-locked loop can be obtained for:

[0135]

[0136] S420: Inversely deriving an open-loop transfer function of the feedforward orthogonal phase-locked loop based on the closed-loop transfer function of the feedforward orthogonal phase-locked loop;

[0137] According to the closed-loop transfer function of the feedforward orthogonal phase-locked loop, the open-loop transfer function of the feedforward orthogonal phase-locked loop can be deduced. as follows:

[0138]

[0139] Furthermore, the open-loop transfer function of the feedforward quadrature phase-locked loop shows that it is a type III system. For the acceleration and deceleration conditions of the PMSM, the steady-state value of the estimated rotor position error of the permanent magnet synchronous motor can be obtained by using the final value theorem. The calculation formula and results in the s domain are as follows:

[0140]

[0141] Among them, a is the acceleration of the permanent magnet synchronous motor, and lim is the limit symbol. Therefore, for the acceleration and deceleration conditions of the permanent magnet synchronous motor, The result is 0, and the feedforward quadrature phase-locked loop 3 can be used to track the rotor position without static error.

[0142] The open-loop transfer function expression of the traditional orthogonal phase-locked loop is:

[0143]

[0144] Therefore, it can be seen that the traditional orthogonal phase-locked loop is a type II system. For the acceleration and deceleration conditions of the PMSM, the steady-state value of the estimated position error of the permanent magnet synchronous motor rotor can be obtained by using the final value theorem. The calculation formula and results in the s domain are as follows:

[0145]

[0146] It can be seen that for the acceleration and deceleration conditions of the permanent magnet synchronous motor, if the traditional orthogonal phase-locked loop is used, The result is not 0, which leads to a large rotor position estimation error under acceleration and deceleration conditions.

[0147] The above comparison clearly illustrates that the feedforward quadrature phase-locked loop provided by the present invention overcomes the problem of large rotor position tracking error of the conventional quadrature phase-locked loop under acceleration and deceleration conditions of the permanent magnet synchronous motor.

[0148] S430: According to the stability margin of the system, the open-loop transfer function of the feedforward orthogonal phase-locked loop is adjusted.

[0149] The present invention adopts a frequency domain characteristic analysis method to design the key parameters of the permanent magnet synchronous motor speed and rotor position estimation method and system based on a feedforward orthogonal phase-locked loop.

[0150] To ensure the stability margin of the system, the open-loop transfer function of the feedforward orthogonal phase-locked loop is adjusted as follows:

[0151]

[0152] Among them, K and ω z is an intermediate variable, satisfying the following relationship:

[0153]

[0154] The expression of the phase margin PM of the feedforward orthogonal phase-locked loop is:

[0155]

[0156] Where ω c For the introduced intermediate variable, the expression is:

[0157]

[0158] Furthermore, in order to ensure the stability of the control system, the PM value is generally set between 30° and 60°. In order to ensure the dynamic performance and noise suppression capability of the system, ω c It is generally set to 100-200rad / s.

[0159] Further, according to the selected PM and ω c , we can infer ω z And the expression of K:

[0160]

[0161]

[0162] Where tan is the tangent function and sec is the secant function.

[0163] ω z Substitute and K into the following formula and solve the equation to obtain the key parameter k of the permanent magnet synchronous motor speed and rotor position estimation method and system based on the feedforward orthogonal phase-locked loopp1 、k i1 and ω L The numerical value of .

[0164]

[0165] Therefore, as long as PM and ω are determined c The parameter tuning of the improved orthogonal phase-locked loop can be achieved.

[0166] S500: Input the normalized value into the feedforward orthogonal phase-locked loop after parameter tuning to obtain the estimated value of the permanent magnet synchronous motor rotor position and the estimated value of the speed.

[0167] Reference Figure 4 , which shows a schematic diagram of the structure of a permanent magnet synchronous motor speed and rotor position estimation system based on a feedforward orthogonal phase-locked loop provided by an exemplary embodiment of the present invention. The system includes an acquisition module 1, a back electromotive force estimation module 2, a back electromotive force normalization module 3, a parameter setting module 4 and a feedforward orthogonal phase-locked loop 5. Among them,

[0168] Acquisition module 1, used to obtain the stator current and stator voltage of the permanent magnet synchronous motor in a two-phase stationary coordinate system;

[0169] Back electromotive force estimation module 2, used for estimating the back electromotive force of the stator current and stator voltage of the permanent magnet synchronous motor in a two-phase stationary coordinate system;

[0170] A back electromotive force normalization module 3 is used to perform back electromotive force normalization processing on the back electromotive force estimation value;

[0171] Parameter tuning module 4, used for tuning parameters of the feedforward quadrature phase-locked loop;

[0172] The feedforward quadrature phase-locked loop 5 is used to extract the rotor position estimation value and the speed estimation value of the permanent magnet synchronous motor from the back electromotive force normalized value based on the parameters obtained by the parameter tuning module.

[0173] Specifically, the input of the back electromotive force estimation module 2 is the stator current i of the permanent magnet synchronous motor in the two-phase stationary coordinate system. α 、i β and the motor stator voltage u in the two-phase stationary coordinate system α 、u β , the output is the estimated value of the back electromotive force of the permanent magnet synchronous motor in the two-phase stationary coordinate system In order to ensure the robustness of the control system and the speed control performance, the present invention uses a second-order adaptive super-helical sliding mode observer to realize the observation of the back electromotive force of the permanent magnet synchronous motor. Its output is the normalized back electromotive force The calculation process is as follows:

[0174]

[0175]

[0176]

[0177] Among them, L d , L q are the d-axis and q-axis inductances of the permanent magnet synchronous motor respectively, Estimated current for the α-axis, Estimated current for the β axis, is the estimated value of electrical angular velocity, is the estimated value of the α-axis back electromotive force, is the estimated value of β-axis back EMF, To estimate the difference between the α-axis current and the measured value To estimate the difference between the β-axis current and the measured value sign is the sign function, k1 and k2 are the sliding mode gains, μ1 and μ2 are the adaptive coefficients of the sliding mode gains, is the given electrical angular velocity of the permanent magnet synchronous motor.

[0178] In a specific simulation embodiment, the solution of the present invention is verified on a 630kW permanent magnet synchronous motor experimental platform, wherein a permanent magnet synchronous motor speed and rotor position estimation method based on a feedforward orthogonal phase-locked loop is implemented by programming on a digital processing chip model TMS320F28377D.

[0179] Figure 5 The following are the experimental results of a conventional orthogonal phase-locked loop under forward acceleration conditions, where the speed increases from 75r / min to 750r / min, the acceleration time is set to 6s, and the load torque is 4000N.m. Figure 5 The rotor position error in (a) It can be seen that when the permanent magnet synchronous motor runs at a constant speed, Close to 0, Figure 5 The estimated rotor position in (b) and (d) is close to the actual rotor position. Reaching 28.9°, from Figure 5 It is clear from (c) that the estimated rotor position lags behind the actual rotor position. Therefore, when using a traditional quadrature phase-locked loop, there is a large DC offset error in the rotor position under forward acceleration conditions.

[0180] Figure 6 The experimental results of the present invention are shown in the forward acceleration working condition. Figure 5 Same as in. Figure 6 (a) The waveform shows that no matter the permanent magnet synchronous motor is running at a constant speed or accelerating, are close to 0, Figure 6 The estimated rotor position in (b)-(d) is nearly identical to the actual rotor position. Therefore, the present invention can suppress the rotor position DC offset error under acceleration conditions.

[0181] Figure 7 The figure shows the experimental results of a conventional orthogonal phase-locked loop (PLL) under open-loop reverse operation of a permanent magnet synchronous motor. It can be seen that there is a 180° phase difference between the estimated and actual rotor positions, which causes the conventional orthogonal PLL to become unstable and unable to operate in closed loop.

[0182] Figure 8 The figure shows the experimental results of the present invention under the reverse deceleration condition, where the speed is reduced from -750r / min to -75r / min, the deceleration time is set to 6s, and the load torque is -4000N.m. Figure 8 (a) The waveform shows that no matter the PMSM is running at a constant speed or accelerating, are close to 0, Figure 8 The estimated rotor position in (b)-(d) is nearly consistent with the actual rotor position. Therefore, the present invention can suppress the DC offset error of the rotor position under reverse deceleration conditions.

[0183] The above experimental effect diagrams show that the permanent magnet synchronous motor speed and rotor position estimation method based on the improved orthogonal phase-locked loop provided by the present invention can achieve high-performance permanent magnet synchronous motor control and obtain satisfactory control effect.

[0184] In the description provided herein, numerous specific details are described. However, it is understood that embodiments of the present invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of this description.

[0185] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0186] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with this patent can make slight changes or modifications to equivalent embodiments using the above-mentioned technical contents without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the solution of the present invention.

Claims

1. A feedforward quadrature phase-locked loop, characterized in that: include: Phase detector, used to identify the relationship between the normalized value of the input back electromotive force and the rotor position; The rotor position quantization signal value output by the phase detector is: ， Among them, △e is the quantized signal value of the rotor position, is the original estimated value of the rotor position; PI regulator, used to estimate the electrical angular velocity based on the rotor position quantization signal value output by the phase detector; A speed calculation module is used to calculate an estimated speed value of the permanent magnet synchronous motor based on the estimated electrical angular velocity; An integrator is used to integrate the estimated electrical angular velocity to obtain an original estimated value of the rotor position; A feedforward loop is used to obtain a compensation amount for a DC offset error of the rotor position based on a normalized value of back electromotive force and an original estimated value of the rotor position output by an integrator; The input of the low-pass filter of the feedforward loop is the rotor position quantization signal value output by the phase detector. , the output is the compensation sinusoidal component y, and its calculation process in the s domain is as follows: ， in, is the cutoff frequency of the low-pass filter; The input of the low-pass filter 2 of the feedforward loop is the output of the feedforward calculation module , the output is the cosine component x of the compensation amount, and its calculation process in the s domain is as follows: ， The input of the compensation angle calculation module of the feedforward loop is the compensation sine component x and the compensation cosine component y, and the output is the compensation of the position DC offset error. , the calculation process is as follows: ， Among them, atan2 is the inverse tangent function; A summation operation is performed to sum the compensation amount of the rotor position DC offset error and the output of the integrator to obtain an estimated value of the permanent magnet synchronous motor rotor position.

2. The feedforward quadrature phase-locked loop according to claim 1, wherein: The feedforward loop includes: A feedforward calculation module is used to calculate the feedforward amount based on the normalized value of the back electromotive force and the original value of the rotor position output by the integrator; Low-pass filter 1, used for filtering high-frequency components in the rotor position quantization signal value output by the integrator; Low-pass filter 2, used to filter the high-frequency components in the feedforward output by the feedforward calculation module; The compensation angle calculation module is used to calculate the compensation amount of the position DC offset error based on the sine component of the compensation amount output by the low-pass filter 1 and the cosine component of the compensation amount output by the low-pass filter 2.

3. A method for estimating the speed and rotor position of a permanent magnet synchronous motor, characterized by: The method is implemented based on the feedforward orthogonal phase-locked loop according to any one of claims 1-2, and the method includes: Obtain the stator current and stator voltage of the permanent magnet synchronous motor in a two-phase stationary coordinate system; Estimation of back electromotive force of stator current and stator voltage of permanent magnet synchronous motor in two-phase stationary coordinate system; Perform back electromotive force normalization on the back electromotive force estimation value; Perform parameter tuning on the feedforward quadrature phase-locked loop; The normalized value is input into the feedforward orthogonal phase-locked loop after parameter tuning to obtain the estimated value of the permanent magnet synchronous motor rotor position and speed.

4. The method for estimating the speed and rotor position of a permanent magnet synchronous motor according to claim 3, wherein: The back electromotive force estimation adopts a second-order adaptive super-helical sliding mode observer to realize the estimation of the back electromotive force of the permanent magnet synchronous motor. The back electromotive force estimation formula of the permanent magnet synchronous motor is as follows: ， Among them, sign is the sign function, when its input is greater than 0, its output is 1, otherwise it is -1; L d 、L q are the d-axis and q-axis inductances of the permanent magnet synchronous motor respectively; 、 is the stator current of the permanent magnet synchronous motor, 、 is the gain coefficient; for Estimated axis current, for Estimated axis current, To estimate the difference between the α-axis current and the measured value, is the difference between the estimated β-axis current and the measured value.

5. The method for estimating the speed and rotor position of a permanent magnet synchronous motor according to claim 3, wherein: Normalized value of the back EMF estimate 、 for: ， in, 、 are the components of the estimated back electromotive force of the permanent magnet synchronous motor under the α-axis and β-axis of the two-phase stationary coordinate system.

6. The method for estimating the speed and rotor position of a permanent magnet synchronous motor according to claim 3, wherein: The parameter tuning of the feedforward quadrature phase-locked loop specifically includes: Establish a small signal model of the feedforward orthogonal phase-locked loop and derive the closed-loop transfer function of the feedforward orthogonal phase-locked loop; The open-loop transfer function of the feedforward orthogonal phase-locked loop is deduced from the closed-loop transfer function of the feedforward orthogonal phase-locked loop; According to the stability margin of the system, the open-loop transfer function of the feedforward orthogonal phase-locked loop is tuned.

7. The method for estimating the speed and rotor position of a permanent magnet synchronous motor according to claim 6, wherein: According to the stability margin of the system, the open-loop transfer function of the feedforward orthogonal phase-locked loop is adjusted, and the open-loop transfer function of the feedforward orthogonal phase-locked loop is adjusted to the following formula: ， Among them, K and is an intermediate variable, satisfying the following relationship: ， The expression of the phase margin PM of the feedforward orthogonal phase-locked loop is: ， In the formula For the introduced intermediate variable, the expression is: 。 8. The method for estimating the speed and rotor position of a permanent magnet synchronous motor according to claim 7, wherein: The PM is set between, Set to 100-200rad / s.

9. A permanent magnet synchronous motor speed and rotor position estimation system based on a feedforward quadrature phase-locked loop, characterized by: The system includes: An acquisition module is used to obtain the stator current and stator voltage of the permanent magnet synchronous motor in a two-phase stationary coordinate system; Back electromotive force estimation module, used to estimate the back electromotive force of the permanent magnet synchronous motor stator current and stator voltage in a two-phase stationary coordinate system; A back electromotive force normalization module is used to perform back electromotive force normalization processing on the back electromotive force estimation value; Parameter tuning module, used for tuning parameters of feedforward quadrature phase-locked loop; The feedforward orthogonal phase-locked loop described in any one of claims 1-2 is used to extract the rotor position estimation value and the speed estimation value of the permanent magnet synchronous motor from the normalized back electromotive force value based on the parameters obtained using the parameter tuning module.

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