Permanent magnet synchronous motor sensorless control phase error compensation method

Abstract

The invention discloses a permanent magnet synchronous motor sensorless control phase error compensation method, and belongs to the technical field of permanent magnet synchronous motor sensorless control. The method solves the problems that the existing method cannot realize closed-loop compensation, the compensation effect is influenced by motor parameters, and the phase error of the sensorless algorithm cannot be detected. According to the method, the torque values of the motor in the two working states are obtained by changing the excitation current reference value, and then the torque error value is obtained by subtraction. And then establishing a function relationship between the torque error and the phase error, and compensating the phase error through the torque error. According to the invention, the magnitude of the torque difference value is utilized to reflect the phase error, the error in the compensation phase can be effectively detected, and the online closed-loop compensation of the phase error is realized. The influence of the parameter change of the motor is counteracted in the process of making the difference between the torques of the two working points, so that the robustness is relatively high. The method can be applied to position-sensorless control phase error compensation.

Description

Technical Field

[0001] The present invention belongs to the technical field of position sensorless control of permanent magnet synchronous motors, and in particular relates to a phase error compensation method for position sensorless control of permanent magnet synchronous motors. Background Art

[0002] Permanent magnet synchronous motors (PMSMs) are widely used in applications such as household appliances and new energy vehicles due to their high efficiency, high power density, and excellent dynamic performance. Traditional PMSM control typically relies on position sensors (such as rotary encoders or Hall sensors) to detect rotor position. However, position sensors not only increase cost and complexity but also reduce system reliability. Consequently, sensorless control technology has become a research hotspot.

[0003] Sensorless control estimates rotor position information using current, voltage, and motor parameters. However, in practical applications, motor parameters (such as stator inductance and stator resistance) vary during operation due to factors such as temperature fluctuations and saturation effects, which can cause phase estimation errors and degrade control performance. To compensate for phase errors, some scholars have proposed solutions. For example, Reference 1 (Correction of rotor position estimation error for high-speed permanent magnet synchronous motor sensorless drive system based on minimum-current-tracking method) analyzes the constant torque curve of a surface-mounted permanent magnet synchronous motor using the minimum current vector method. When the constant torque curve is no longer parallel to the d-axis due to parameter changes, the position error correction result is affected. Furthermore, Reference 2 (Online temperature identification strategy for position sensorless PMSM drives with position error adaptive compensation) applies the minimum current vector amplitude method to an interior permanent magnet synchronous motor by establishing a functional relationship between different coordinate systems. However, this method is affected by parameter accuracy. Reference 3 (Simple and effective online position error compensation method for sensorless SPMSM drives) effectively identifies load-related position estimation errors in surface-mounted permanent magnet synchronous motors based on a torque characteristic method. However, this method is an open-loop control method. If errors still exist in the compensated phase, they cannot be effectively detected, making closed-loop compensation impossible. Furthermore, this method is still inherently affected by motor parameters.

[0004] To sum up, the existing methods still cannot achieve closed-loop compensation, the compensation effect will be affected by the motor parameters, and are highly sensitive to changes in motor parameters. In addition, they cannot detect errors in the compensation phase. It is currently urgent to propose a new phase error compensation method to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems that the existing methods cannot achieve closed-loop compensation, the compensation effect is affected by motor parameters, and the phase error of the position sensorless algorithm cannot be detected, and a phase error compensation method for permanent magnet synchronous motor position sensorless control is proposed.

[0006] The technical solution adopted by the present invention to solve the above technical problems is: a method for compensating phase error of position sensorless control of a permanent magnet synchronous motor, the method specifically comprising the following steps:

[0007] Step 1, initialize the number of iterative compensations l=1;

[0008] Step 2: Collect the torque current i of the motor in a stable operating state sq1,l and the excitation current i sd1,l , and then according to the torque current i sq1,l and the excitation current i sd1,l Calculate the electromagnetic torque T of the motor in stable operation state e1,l ;

[0009] Step 3: Change the excitation current reference value and collect the torque current i after the motor re-enters the stable working state. sq2,l and the excitation current i sd2,l , and then according to the torque current i sq2,l and the excitation current i sd2,l Calculate the electromagnetic torque T of the motor when the excitation current reference value changes e2,l ;

[0010] Step 4: According to the electromagnetic torque T e1,l and electromagnetic torque T e2,l To calculate the torque error ΔT e,l , and compare the torque error ΔT e,l and the set torque error threshold ΔT e-min,l Size:

[0011] If ΔT e,l <ΔT e-min,l , then the phase error compensation is ended;

[0012] If ΔT e,l ≥ΔT e-min,l , then proceed to step 5;

[0013] Step 5: Obtain the rotor phase error compensation angle Δθ based on the torque error calculated in step 4 l ;

[0014] Step 6: Use the rotor phase error to compensate the angle After compensating for the rotor phase error, set l=l+1 and return to step 2.

[0015] Furthermore, in step 1, the number of iterative compensations is initialized to l=1;

[0016] Step 2: Collect the torque current i of the motor in a stable operating state sq1,l and the excitation current i sd1,l , and then according to the torque current isq1,l and the excitation current i sd1,l Calculate the electromagnetic torque T of the motor in stable operation state e1,l ;

[0017] Step 3: Change the excitation current reference value and collect the torque current i after the motor re-enters the stable working state. sq2,l and the excitation current i sd2,l , and then according to the torque current i sq2,l and the excitation current i sd2,l Calculate the electromagnetic torque T of the motor when the excitation current reference value changes e2,l ;

[0018] Step 4: According to the electromagnetic torque T e1,l and electromagnetic torque T e2,l To calculate the torque error ΔT e,l , and compare the torque error ΔT e,l and the set torque error threshold ΔT e-min,l Size:

[0019] If ΔT e,l <ΔT e-min,l , then the phase error compensation is ended;

[0020] If ΔT e,l ≥ΔT e-min,l , then proceed to step 5;

[0021] Step 5: Obtain the rotor phase error compensation angle Δθ based on the torque error calculated in step 4 l ;

[0022] Step 6: Use the rotor phase error to compensate the angle After compensating for the rotor phase error, set l=l+1 and return to step 2.

[0023] Furthermore, in step 3, changing the excitation current reference value is specifically as follows:

[0024] i′ d,ref =i d,ref -Δi d,ref

[0025] Among them, i d,ref is the original excitation current reference value;

[0026] Δi d,ref is the change in the excitation current reference value;

[0027] i′ d,ref is the changed excitation current reference value.

[0028] Furthermore, the torque current isq2,l and the excitation current i sd2,l Calculate the electromagnetic torque T of the motor when the excitation current reference value changes e2,l , specifically:

[0029]

[0030] Among them, T e2,l It is the electromagnetic torque of the motor when the excitation current reference value changes.

[0031] Furthermore, the specific process of step 4 is as follows:

[0032] ΔT e,l =T e1,l -T e2,l

[0033] Where ΔT e,l is the torque error.

[0034] Furthermore, the specific process of step 5 is as follows:

[0035] Δθ l =k i ΔT e,l

[0036] Where Δθ l is the rotor phase error compensation angle;

[0037] k i is the slope of the phase error relative to the torque error.

[0038] Furthermore, the calculation process of the slope of the phase error relative to the torque error is:

[0039] Derivative of the torque error with respect to the rotor phase error yields:

[0040]

[0041] Among them, i s1,l is the steady-state current amplitude before the excitation current changes, is the rotor phase angle calculated by the low-pass second-order filter observer before the excitation current changes, i s2,l is the steady-state current amplitude after the excitation current changes; is the rotor phase angle calculated by the low-pass second-order filter observer after the excitation current changes;

[0042] Then the slope of the phase error relative to the torque error is:

[0043]

[0044] Among them, k iis the slope of the phase error relative to the torque error.

[0045] Furthermore, the rotor phase error compensation angle The specific process of compensating the rotor phase error is:

[0046]

[0047] in, is the rotor phase error before compensation;

[0048] is the rotor phase error after compensation.

[0049] The beneficial effects of the present invention are:

[0050] The present invention obtains the torque value of the motor in two working states by changing the excitation current reference value, and then obtains the torque error value by making a difference. Then, a functional relationship between the torque error and the phase error is established, and the phase error is compensated by the torque error. Since the change of the motor parameters will cause the torque calculation under the two working conditions to change at the same time, the influence of the change of the motor parameters is offset in the process of making a difference in the torque of the two working points, thereby reducing the sensitivity of the method of the present invention to the change of the motor parameters and ensuring the effect of phase error compensation. Moreover, the method of the present invention uses whether the size of the torque difference meets the required range to reflect the phase error, which can effectively detect the error in the compensated phase, and can realize online closed-loop compensation of the phase error, thereby improving the accuracy of the rotor position estimation. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is a structural block diagram of a method for compensating phase error of a position sensorless control of a permanent magnet synchronous motor according to the present invention;

[0052] Figure 2 The experimental results of the phase error compensation method of the present invention are as follows: when the motor is running at 1600 r / min and a phase error of 30° is suddenly added under 30% rated load;

[0053] Figure 3 When the motor is running at 1000r / min at 25% rated load, the inductance parameter is L S Mutation to 0.3L S Experimental results of the phase error compensation method of the present invention under the condition of;

[0054] Figure 4 When the motor is running at 1000r / min at 25% rated load, the inductance parameter is L S Mutated to 1.7L S Experimental results of the phase error compensation method of the present invention under the condition of;

[0055] Figure 5 When the motor is running at 1000r / min at 80% rated load, the inductance parameter is L S Mutation to 0.3L S Experimental results of the phase error compensation method of the present invention under the condition of;

[0056] Figure 6 When the motor is running at 1000r / min at 80% rated load, the inductance parameter is L S Mutated to 1.7L S Experimental results of the phase error compensation method of the present invention under the condition of;

[0057] Figures 2 to 6 In the figure, the horizontal axis of the curve is time. DETAILED DESCRIPTION

[0058] Specific implementation method 1: Combination Figure 1 This embodiment describes a method for compensating phase error in position sensorless control of a permanent magnet synchronous motor, the method specifically comprising the following steps:

[0059] Step 1, initialize the number of iterative compensations l=1;

[0060] Step 2: Collect the torque current i of the motor in a stable operating state sq1,l and the excitation current i sd1,l , and also the torque current i sq1 It is called the d-axis fundamental current, and the excitation current i sd1 It is called the q-axis fundamental current, and then according to the torque current i sq1,l and the excitation current i sd1,l Calculate the electromagnetic torque T of the motor in stable operation state e1,l ;

[0061] Step 3: Change the excitation current reference value and collect the torque current i after the motor re-enters the stable working state. sq2,l and the excitation current i sd2,l , and then according to the torque current i sq2,l and the excitation current i sd2,l Calculate the electromagnetic torque T of the motor when the excitation current reference value changes e2,l ;

[0062] Step 4: According to the electromagnetic torque T e1,l and electromagnetic torque T e2,l To calculate the torque error ΔT e,l , and compare the torque error ΔT e,l and the set torque error threshold ΔT e-min,l Size:

[0063] If ΔT e,l <ΔT e-min,l , then the phase error compensation is ended;

[0064] If ΔT e,l ≥ΔT e-min,l , then proceed to step 5;

[0065] Step 5: Obtain the rotor phase error compensation angle Δθ based on the torque error calculated in step 4 l ;

[0066] Step 6: Use the rotor phase error to compensate the angle After compensating for the rotor phase error, set l=l+1 and return to step 2.

[0067] The present invention uses torque error as a criterion for determining whether phase error compensation is necessary. When the torque error is within the required range, the rotor phase is considered close to the actual phase, and phase error compensation ends. If the torque error is not within the required range, phase error compensation is performed iteratively until the torque error is within the required range.

[0068] Specific implementation method 2: This implementation method is a further limitation of the specific implementation method 1. sq1,l and the excitation current i sd1,l Calculate the electromagnetic torque T of the motor in stable operation state e1,l The specific process is:

[0069]

[0070] Where p is the number of pole pairs;

[0071] ψ f is the permanent magnet flux;

[0072] L d is the d-axis inductance;

[0073] L q is the q-axis inductance.

[0074] Other steps and parameters are the same as those in the first embodiment.

[0075] Specific embodiment 3: This embodiment is a further limitation of specific embodiment 2. In step 3, the excitation current reference value is changed as follows:

[0076] i′ d,ref =i d,ref -Δi d,ref

[0077] Among them, i d,refis the original excitation current reference value;

[0078] Δi d,ref is the change in the excitation current reference value;

[0079] i′ d,ref is the changed excitation current reference value.

[0080] Other steps and parameters are the same as those in the second embodiment.

[0081] Specific implementation method 4: This implementation method is a further limitation of specific implementation method 3. sq2,l and the excitation current i sd2,l Calculate the electromagnetic torque T of the motor when the excitation current reference value changes e2,l , specifically:

[0082]

[0083] Among them, T e2,l It is the electromagnetic torque of the motor when the excitation current reference value changes.

[0084] Other steps and parameters are the same as those in the third embodiment.

[0085] Specific implementation method 5: This implementation method further limits the specific implementation method 4. The specific process of step 4 is as follows:

[0086] ΔT e,l =T e1,l -T e2,l

[0087] Where ΔT e,l is the torque error.

[0088] Other steps and parameters are the same as those in the fourth embodiment.

[0089] Specific implementation method 6: This implementation method further limits the specific implementation method 5. The specific process of step 4 is as follows:

[0090] The specific process of step 5 is as follows:

[0091] Δθ l =k i ΔT e,l

[0092] Where Δθ l is the rotor phase error compensation angle;

[0093] k i is the slope of the phase error relative to the torque error.

[0094] Other steps and parameters are the same as those in the fifth embodiment.

[0095] Specific embodiment seven: This embodiment further limits specific embodiment six. The calculation process of the slope of the phase error relative to the torque error is:

[0096] Derivative of the torque error with respect to the rotor phase error yields:

[0097]

[0098] Among them, i s1,l is the steady-state current amplitude before the excitation current changes, is the rotor phase angle calculated by the low-pass second-order filter observer before the excitation current changes, i s2,l is the steady-state current amplitude after the excitation current changes; is the rotor phase angle calculated by the low-pass second-order filter observer after the excitation current changes;

[0099] Then the slope of the phase error relative to the torque error is:

[0100]

[0101] Among them, k i is the slope of the phase error relative to the torque error.

[0102] The parameter relationship of this embodiment satisfies: According to i sd1,l You can get i s1,l and According to i sd2,l You can get i s2,l and And satisfying

[0103] Other steps and parameters are the same as those in the sixth embodiment.

[0104] Specific embodiment eight: This embodiment is a further limitation of specific embodiment seven, wherein the rotor phase error compensation angle is used. The specific process of compensating the rotor phase error is:

[0105]

[0106] in, is the rotor phase error before compensation;

[0107] is the rotor phase error after compensation.

[0108] Other steps and parameters are the same as those in the seventh embodiment.

[0109] Below through Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 as well as Figure 6 The experimental results shown are used to verify the effectiveness of the method proposed in this invention. Figure 2 Figure 3 shows the experimental results of phase error correction using the method of the present invention when the motor is running at 1600 r / min and a phase error of 30° is suddenly added at 30% of the rated load. The waveforms from top to bottom are phase error, d-axis current, calculated phase error compensation value, torque error, rotor phase calculated by the positionless control algorithm, and actual phase, indicating that the method of the present invention can well calculate phase error and realize online compensation at high speed and large lag angle.

[0110] Figure 3 and Figure 4 These are the experimental results of changing the motor parameters when the motor is running at a steady state of 1000r / min and the load is light (25% of the rated load). Figure 5 and Figure 6 These are the experimental results of changing the motor parameters under heavy load (80% of rated load) when the motor is running in a steady state at 1000 r / min. The experimental results show that the phase error caused by the change of motor parameters can be effectively suppressed by the method of the present invention to achieve precise orientation.

[0111] The above examples are merely illustrative of the calculation model and process of the present invention and are not intended to limit the embodiments of the present invention. Persons skilled in the art will readily appreciate that other variations or modifications based on the above description are possible. This list of embodiments is not exhaustive; however, any obvious variations or modifications derived from the technical solution of the present invention remain within the scope of protection of the present invention.

Claims

1. A method for compensating phase error of a permanent magnet synchronous motor without position sensor control, characterized in that: The method specifically comprises the following steps: Step 1, initialize the number of iterative compensations l=1; Step 2: Collect the torque current i of the motor in a stable operating state sq1,l and the excitation current i sd1,l , and then according to the torque current i sq1,l and the excitation current i sd1,l Calculate the electromagnetic torque T of the motor in stable operation state e1,l ; Step 3: Change the excitation current reference value and collect the torque current i after the motor re-enters the stable working state. sq2,l and the excitation current i sd2,l , and then according to the torque current i sq2,l and the excitation current i sd2,l Calculate the electromagnetic torque T of the motor when the excitation current reference value changes e2,l ; Step 4: According to the electromagnetic torque T e1,l and electromagnetic torque T e2,l To calculate the torque error ΔT e,l , and compare the torque error ΔT e,l and the set torque error threshold ΔT e-min,l Size: If ΔT e,l <ΔT e-min,l , then the phase error compensation is ended; If ΔT e,l ≥ΔT e-min,l , then proceed to step 5; Step 5: Obtain the rotor phase error compensation angle Δθ based on the torque error calculated in step 4 l ; Step 6: Use the rotor phase error to compensate the angle After compensating for the rotor phase error, set l=l+1 and return to step 2.

2. A method for compensating phase error of position sensorless control of a permanent magnet synchronous motor according to claim 1, characterized in that: The torque current i sq1,l and the excitation current i sd1,l Calculate the electromagnetic torque T of the motor in stable operation state e1,l The specific process is: Where p is the number of pole pairs; ψ f is the permanent magnet flux; L d is the d-axis inductance; L q is the q-axis inductance.

3. A method for compensating phase error of position sensorless control of a permanent magnet synchronous motor according to claim 2, characterized in that: In step 3, the excitation current reference value is changed as follows: i′ d,ref =i d,ref -Δi d,ref Among them, i d,ref is the original excitation current reference value; Δi d,ref is the change in the excitation current reference value; i′ d,ref is the changed excitation current reference value.

4. A method for compensating phase error in position sensorless control of a permanent magnet synchronous motor according to claim 3, characterized in that: The torque current i sq2,l and the excitation current i sd2,l Calculate the electromagnetic torque T of the motor when the excitation current reference value changes e2,l , specifically: Among them, T e2,l It is the electromagnetic torque of the motor when the excitation current reference value changes.

5. A method for compensating phase error in position sensorless control of a permanent magnet synchronous motor according to claim 4, characterized in that: The specific process of step 4 is as follows: ΔT e,l =T e1,l -T e2,l Where, ΔT e,l is the torque error.

6. A method for compensating phase error in position sensorless control of a permanent magnet synchronous motor according to claim 5, characterized in that: The specific process of step 5 is as follows: Dth l =k i ·ΔT e,l Where Δθ l is the rotor phase error compensation angle; k i is the slope of the phase error relative to the torque error.

7. A method for compensating phase error in position sensorless control of a permanent magnet synchronous motor according to claim 6, characterized in that: The calculation process of the slope of the phase error relative to the torque error is: Derivative of the torque error with respect to the rotor phase error yields: Among them, i s1,l is the steady-state current amplitude before the excitation current changes, is the rotor phase angle calculated by the low-pass second-order filter observer before the excitation current changes, i s2,l is the steady-state current amplitude after the excitation current changes; is the rotor phase angle calculated by the low-pass second-order filter observer after the excitation current changes; Then the slope of the phase error relative to the torque error is: Among them, k i is the slope of the phase error relative to the torque error.

8. The method for compensating phase error of position sensorless control of a permanent magnet synchronous motor according to claim 7, characterized in that: The rotor phase error compensation angle is used The specific process of compensating the rotor phase error is: in, is the rotor phase error before compensation; is the rotor phase error after compensation.

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