Method and device for closed-loop acquisition of inductance parameters of permanent magnet motor for electric vehicle

Abstract

The invention relates to a closed-loop acquisition method and device for inductance parameters of a permanent magnet motor for an electric vehicle, and the method comprises the steps: randomly selecting any two phases of a three-phase line of the motor, and connecting a test device 1 with a motor winding; an excitation reference voltage is given by a test device 1, an output current is sampled, and a closed-loop adjustable system is constructed according to information of the excitation reference voltage and the output current. A closed-loop adjustable item can be constructed by sampling an output current to obtain a stable d-axis and q-axis inductance parameter Ldq, and then a relationship between d-axis self-inductance Ldd, q-axis self-inductance Lqq, d-axis inductance Ld and q-axis inductance Lq of the motor and an electric angle theta e of the motor can be obtained through angle displacement. Compared with the prior art, the method has the advantages that the method is not easily influenced by noise, and the obtained result is more stable and accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of inductance parameter acquisition, and in particular to a closed-loop acquisition method and device for inductance parameters of a permanent magnet motor for an electric vehicle. Background Art

[0002] The inductance parameter of a permanent magnet synchronous motor is an important parameter that can be widely used in motor control. For example, Chinese patent CN102761307A uses the inductance parameter to achieve motor control.

[0003] The related prior art proposes two methods for measuring the inductance parameters of a motor. One is to connect the measuring device between the U phase and the VW phase of the motor, with the VW phases connected in parallel; the other is to connect the measuring device between two phases of the motor with the third phase disconnected, for example, between the U phase and the V phase, with the W phase disconnected. In both methods, the measuring device generates a high-frequency excitation signal, and the inductance is calculated based on the amplitude of the corresponding high-frequency current.

[0004] Then, in the prior art, the process of acquiring inductance parameters is open-loop, and high-frequency current is directly AD sampled without amplitude inspection or waveform distortion judgment. It is easy to produce deviations in the results due to noise interference, thereby affecting the accuracy of the acquired inductance parameters. Summary of the invention

[0005] The purpose of the present invention is to provide a closed-loop acquisition method and device for the inductance parameters of a permanent magnet motor for an electric vehicle.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A closed-loop acquisition method for inductance parameters of a permanent magnet motor for an electric vehicle, comprising:

[0008] Generate an excitation voltage, apply the excitation voltage to the motor stator, and collect the output current of the motor;

[0009] An initial impedance calculation value is obtained based on the amplitude of the excitation voltage;

[0010] An estimated value of the magnitude of the excitation voltage is obtained based on the initial impedance calculation value combined with the excitation voltage and the output current;

[0011] The estimated value of the excitation voltage amplitude and the excitation voltage amplitude are used as inputs, and the corrected impedance calculation value is obtained after PI adjustment;

[0012] An estimated value of the amplitude of the excitation voltage is obtained based on the corrected impedance calculation value combined with the excitation voltage and the output current;

[0013] The inductance parameters are obtained based on the corrected impedance calculation value.

[0014] The method of obtaining an estimated value of the amplitude of the excitation voltage based on the corrected impedance calculation value combined with the excitation voltage and the output current includes:

[0015] Multiply the corrected impedance calculation by the output current;

[0016] The square of the estimated voltage is obtained by multiplying the corrected impedance calculated value by the output current;

[0017] Square the excitation voltage;

[0018] The square of the estimated voltage and the square of the excitation voltage are added together to obtain an estimated value of the amplitude of the excitation voltage.

[0019] The inductance parameter is obtained according to the corrected impedance calculation value, including:

[0020] Performing filtering on the corrected impedance calculation value;

[0021] The inductance parameter is obtained based on the impedance calculation value after filtering.

[0022] A closed-loop acquisition method for inductance parameters of a permanent magnet motor for an electric vehicle, comprising:

[0023] Generate an excitation voltage, apply the excitation voltage to the motor stator, and collect the output current of the motor;

[0024] Obtaining a first process voltage value based on the excitation voltage and a unit sinusoidal signal with the same frequency and phase;

[0025] Obtaining an initial second process voltage value based on the output current and a unit cosine signal with the same frequency and phase;

[0026] The first process voltage value and the second process voltage value are adjusted by PI to obtain an impedance calculation value;

[0027] A corrected second process voltage value is obtained based on the output current, a unit cosine signal with the same frequency and phase, and an impedance calculation value;

[0028] The inductance parameters are obtained based on the impedance calculation value.

[0029] The step of obtaining the inductance parameter according to the impedance calculation value includes:

[0030] Filtering the impedance calculation value;

[0031] The inductance parameter is obtained based on the impedance calculation value after filtering.

[0032] A closed-loop acquisition device for inductance parameters of a permanent magnet motor for an electric vehicle, comprising:

[0033] The excitation and sampling module is configured to: generate an excitation voltage, apply the excitation voltage to the motor stator, and collect the output current of the motor;

[0034] A first impedance calculation module is configured to: obtain an initial impedance calculation value based on the amplitude of the excitation voltage, and obtain a corrected impedance calculation value after PI adjustment by taking the estimated value of the amplitude of the excitation voltage and the amplitude of the excitation voltage as input;

[0035] An amplitude estimation module is configured to obtain an estimated value of the amplitude of the excitation voltage based on an initial impedance calculation value combined with the excitation voltage and the output current, and obtain an estimated value of the amplitude of the excitation voltage based on a corrected impedance calculation value combined with the excitation voltage and the output current;

[0036] The inductance parameter calculation module is configured to obtain the inductance parameter according to the corrected impedance calculation value.

[0037] The amplitude estimation module comprises:

[0038] A first multiplier is configured to: multiply the initial impedance calculation value by the output current, and multiply the corrected impedance calculation value by the output current to obtain an estimated voltage;

[0039] A first squarer is configured to: square the estimated voltage to obtain the square of the estimated voltage;

[0040] The second squarer is configured to: square the excitation voltage;

[0041] The accumulator is configured to: add the square of the estimated voltage and the square of the excitation voltage to obtain an estimated value of the amplitude of the excitation voltage.

[0042] The inductance parameter calculation module includes:

[0043] The filter is configured to: filter the corrected impedance calculation value;

[0044] The divider is configured to obtain an inductance parameter based on the impedance calculation value after filtering.

[0045] A closed-loop acquisition device for inductance parameters of a permanent magnet motor for an electric vehicle, comprising:

[0046] The excitation and sampling module is configured to: generate an excitation voltage, apply the excitation voltage to the motor stator, and collect the output current of the motor;

[0047] A first voltage calculation module is configured to: obtain a first process voltage value based on the excitation voltage and a unit sinusoidal signal with the same frequency and phase;

[0048] A second voltage calculation module is configured to: obtain an initial second process voltage value based on the output current and a unit cosine signal with the same frequency and phase, and obtain a modified second process voltage value based on the output current, the unit cosine signal with the same frequency and phase, and an impedance calculation value;

[0049] The second impedance calculation module is configured to: obtain an impedance calculation value after PI adjustment of the first process voltage value and the second process voltage value;

[0050] The inductance parameter calculation module is configured to obtain the inductance parameter according to the impedance calculation value.

[0051] The inductance parameter calculation module includes:

[0052] The filter is configured to: filter the impedance calculation value;

[0053] The divider is configured to obtain an inductance parameter based on the impedance calculation value after filtering.

[0054] Compared with the prior art, the present invention has the following beneficial effects: the parameters are obtained through a closed-loop method, which is less susceptible to noise than an open-loop method, and the obtained results are more stable and accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 is the permanent magnet motor d-axis self-inductance L dd , d-axis inductance L d And the q-axis inductance L q and the motor electrical angle θ e Schematic diagram of the relationship between;

[0056] Figure 2 is the q-axis self-inductance L of the permanent magnet motor qq , d-axis inductance L d And the q-axis inductance L q and the motor electrical angle θ e Schematic diagram of the relationship between;

[0057] Figure 3 It is a schematic diagram of the connection between the measuring device and any two phases of the motor;

[0058] Figure 4 In accordance with Figure 3 The dq-axis mutual inductance L of the connected permanent magnet motor dq , d-axis inductance L d And the q-axis inductance L q and the motor electrical angle θ e Schematic diagram between;

[0059] Figure 5 A schematic diagram of the principle of the present invention;

[0060] Figure 6 This is a control block diagram of Embodiment 1 of the present invention;

[0061] Figure 7 This is a control block diagram of Embodiment 2 of the present invention;

[0062] Figure 8 This is a schematic diagram of the inductance parameter acquisition result of Example 1 of the present invention;

[0063] Fig. 9 This is a schematic diagram of the inductance parameter acquisition result of Example 2 of the present invention;

[0064] Among them: 1. test equipment, 101. first regulator, 102. first multiplier, 103. first squarer, 104. second squarer, 105. accumulator, 106. filter, 107. divider, 108. third multiplier, 109. second multiplier, 110. second regulator. DETAILED DESCRIPTION

[0065] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0066] This application obtains the inductance parameters of the permanent magnet motor, such as Figure 3 As shown, considering that the inductance of the permanent magnet motor for electric vehicles is large, the AC impedance of the phase resistance relative to the winding inductance is less than 1%, so the phase resistance is ignored. Select any two phases of the three-phase line of the motor at random, and connect the test equipment 1 to the motor winding. Use the test equipment 1 to give an excitation reference voltage, sample the output current, and build a closed-loop adjustable system based on the information of the two.

[0067] Measure the inductance parameter L dq Later, if Figure 1 , Figure 2 and Figure 4 As shown, the motor d-axis self-inductance L can be obtained by angle shifting. dd , q-axis self-inductance L qq , d-axis inductance L d And the q-axis inductance L q and the motor electrical angle θ e The relationship between.

[0068] Specifically, given the excitation voltage V in =V m cos(2πf e t), so that the motor line inductance corresponds to the AC impedance Z dq =j·4πf e ·Ldq , whose modulus is |Z dq |=4πf e ·L dq , the output current I out for:

[0069]

[0070]

[0071] Where: V m is the amplitude of the excitation voltage, f e is the frequency of the excitation voltage, |I out | is the amplitude of the output current.

[0072] From the output current sampling, a closed-loop adjustable term can be constructed to obtain a stable inductance value. The overall concept is as follows Figure 5 shown.

[0073] Example 1

[0074] A closed-loop method for obtaining inductance parameters of a permanent magnet motor for electric vehicles is provided. Figure 6 The closed-loop inductance parameter acquisition device shown is implemented, and the acquisition process specifically includes:

[0075] (1) Generate excitation voltage V in , apply the excitation voltage to the motor stator and collect the motor output current I out ;

[0076] (2) Based on the amplitude of the excitation voltage, the initial impedance calculation value Z is obtained dq_est Specifically, the amplitude of the excitation voltage is first squared, and then the impedance calculation value is obtained based on the square of the amplitude of the excitation voltage. In this process, since the impedance calculation value is obtained by the first regulator, but in the initial state, there is no feedback of the estimated value of the amplitude of the excitation voltage, an estimated value of the amplitude of the excitation voltage with a deviation can be randomly generated. Of course, other conventional means can also be used.

[0077] (3) Based on the initial impedance calculation value, combined with the excitation voltage and output current, the estimated value of the excitation voltage amplitude V is obtained. 2 m_est Specifically, the process may include:

[0078] Multiply the initial impedance calculation by the output current;

[0079] The square of the estimated voltage is obtained by multiplying the initial impedance calculation value by the output current.

[0080] Square the excitation voltage;

[0081] The estimated value V of the excitation voltage is obtained by adding the square of the estimated voltage and the excitation voltage. 2 m_est .

[0082] (4) taking the estimated value of the excitation voltage amplitude and the excitation voltage amplitude as input, and obtaining the corrected impedance calculation value after PI adjustment;

[0083] (5) Based on the corrected impedance calculation value combined with the excitation voltage and output current, the estimated value of the excitation voltage amplitude V is obtained. 2 m_est Specifically, the process may include:

[0084] Multiply the corrected impedance calculation by the output current;

[0085] The square of the estimated voltage is obtained by multiplying the corrected impedance calculated value by the output current;

[0086] Square the excitation voltage;

[0087] The estimated value V of the excitation voltage is obtained by adding the square of the estimated voltage and the excitation voltage. 2 m_est .

[0088] (5) Based on the corrected impedance calculation value Z dq_est Get the inductance parameter L dq , specifically, may include:

[0089] The corrected impedance calculated value Z dq_est Perform filtering processing;

[0090] The inductance parameter L is obtained based on the impedance calculation value after filtering. dq .

[0091] The results of obtaining the inductance parameters are as follows: Figure 8 In Example 1, the input of the regulator is all DC, so from the perspective of control theory, it is easier to adjust the parameters of the regulator, and the bandwidth of the regulator can be easily designed to be higher, so the response is faster.

[0092] Example 2

[0093] A closed-loop method for obtaining inductance parameters of a permanent magnet motor for electric vehicles is provided. Figure 7 The closed-loop inductance parameter acquisition device shown is implemented, and the acquisition process specifically includes:

[0094] (1) Generate excitation voltage V in , apply the excitation voltage to the motor stator and collect the motor output current I out

[0095] (2) Based on the excitation voltage V in and the unit sinusoidal signal sin(2πf e t) obtain the first process voltage value, which is specifically to set the excitation voltage V in and the unit sinusoidal signal sin(2πf e t) are multiplied by the third multiplier.

[0096] (3) Based on the output current I out and the unit cosine signal cos(2πf e t) obtaining an initial second process voltage value;

[0097] (4) The first process voltage value and the second process voltage value are adjusted by PI to obtain the impedance calculation value Z dq_est ;

[0098] (5) Based on the output current I out , the unit cosine signal cos(2πf e t) and impedance calculation value Z dq_est The corrected second process voltage value is obtained. Specifically, the output current I out , the unit cosine signal cos(2πf e t) and impedance calculation value Z dq_est Multiplied by the second multiplier.

[0099] (6) Obtain the inductance parameter L based on the impedance calculation value dq , similarly, this process specifically includes:

[0100] Calculated impedance value Z dq_est Perform filtering processing;

[0101] The inductance parameter L is obtained based on the impedance calculation value after filtering. dq .

[0102] The results of obtaining the inductance parameters are as follows: Fig. 9 Embodiment 2 is more similar to the heterodyne method in the phase-locked loop theory, which can achieve phase synchronization of different AC signals and reduce the complexity of implementation in specific applications.

[0103] If the above functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program code.

Claims

1. A closed-loop acquisition method for inductance parameters of a permanent magnet motor for electric vehicles, characterized in that: include: Generate an excitation voltage, apply the excitation voltage to the motor stator, and collect the output current of the motor; An initial impedance calculation value is obtained based on the amplitude of the excitation voltage; An estimated value of the magnitude of the excitation voltage is obtained based on the initial impedance calculation value combined with the excitation voltage and the output current; The estimated value of the excitation voltage amplitude and the excitation voltage amplitude are used as inputs, and the corrected impedance calculation value is obtained after PI adjustment; An estimated value of the amplitude of the excitation voltage is obtained based on the corrected impedance calculation value combined with the excitation voltage and the output current; The inductance parameters are obtained based on the corrected impedance calculation value.

2. The closed-loop acquisition method of inductance parameters of a permanent magnet motor for electric vehicles according to claim 1 is characterized in that: The method of obtaining an estimated value of the amplitude of the excitation voltage based on the corrected impedance calculation value combined with the excitation voltage and the output current includes: Multiply the corrected impedance calculation by the output current; The square of the estimated voltage is obtained by multiplying the corrected impedance calculated value by the output current; Square the excitation voltage; The square of the estimated voltage and the square of the excitation voltage are added together to obtain an estimated value of the amplitude of the excitation voltage.

3. The closed-loop acquisition method of inductance parameters of a permanent magnet motor for electric vehicles according to claim 1 is characterized in that: The inductance parameter is obtained according to the corrected impedance calculation value, including: Performing filtering on the corrected impedance calculation value; The inductance parameter is obtained based on the impedance calculation value after filtering.

4. A closed-loop method for acquiring inductance parameters of a permanent magnet motor for electric vehicles, characterized in that: include: Generate an excitation voltage, apply the excitation voltage to the motor stator, and collect the output current of the motor; Obtaining a first process voltage value based on the excitation voltage and a unit sinusoidal signal with the same frequency and phase; Obtaining an initial second process voltage value based on the output current and a unit cosine signal with the same frequency and phase; The first process voltage value and the second process voltage value are adjusted by PI to obtain an impedance calculation value; A corrected second process voltage value is obtained based on the output current, a unit cosine signal with the same frequency and phase, and an impedance calculation value; The inductance parameters are obtained based on the impedance calculation value.

5. The closed-loop acquisition method of inductance parameters of a permanent magnet motor for electric vehicles according to claim 4 is characterized in that: The step of obtaining the inductance parameter according to the impedance calculation value includes: Filtering the impedance calculation value; The inductance parameter is obtained based on the impedance calculation value after filtering.

6. A closed-loop acquisition device for inductance parameters of a permanent magnet motor for electric vehicles, characterized in that: include: The excitation and sampling module is configured to: generate an excitation voltage, apply the excitation voltage to the motor stator, and collect the output current of the motor; A first impedance calculation module is configured to: obtain an initial impedance calculation value based on the amplitude of the excitation voltage, and obtain a corrected impedance calculation value after PI adjustment by taking the estimated value of the amplitude of the excitation voltage and the amplitude of the excitation voltage as input; An amplitude estimation module is configured to obtain an estimated value of the amplitude of the excitation voltage based on an initial impedance calculation value combined with the excitation voltage and the output current, and obtain an estimated value of the amplitude of the excitation voltage based on a corrected impedance calculation value combined with the excitation voltage and the output current; The inductance parameter calculation module is configured to obtain the inductance parameter according to the corrected impedance calculation value.

7. The closed-loop acquisition device for inductance parameters of a permanent magnet motor for electric vehicles according to claim 6, characterized in that: The amplitude estimation module comprises: A first multiplier is configured to: multiply the initial impedance calculation value by the output current, and multiply the corrected impedance calculation value by the output current to obtain an estimated voltage; A first squarer is configured to: square the estimated voltage to obtain the square of the estimated voltage; The second squarer is configured to: square the excitation voltage; The accumulator is configured to: add the square of the estimated voltage and the square of the excitation voltage to obtain an estimated value of the amplitude of the excitation voltage.

8. The closed-loop acquisition device for inductance parameters of a permanent magnet motor for electric vehicles according to claim 6, characterized in that: The inductance parameter calculation module includes: The filter is configured to: filter the corrected impedance calculation value; The divider is configured to obtain an inductance parameter based on the impedance calculation value after filtering.

9. A closed-loop acquisition device for inductance parameters of a permanent magnet motor for electric vehicles, characterized in that: include: The excitation and sampling module is configured to: generate an excitation voltage, apply the excitation voltage to the motor stator, and collect the output current of the motor; A first voltage calculation module is configured to: obtain a first process voltage value based on the excitation voltage and a unit sinusoidal signal with the same frequency and phase; A second voltage calculation module is configured to: obtain an initial second process voltage value based on the output current and a unit cosine signal with the same frequency and phase, and obtain a modified second process voltage value based on the output current, the unit cosine signal with the same frequency and phase, and an impedance calculation value; The second impedance calculation module is configured to: obtain an impedance calculation value after PI adjustment of the first process voltage value and the second process voltage value; The inductance parameter calculation module is configured to obtain the inductance parameter according to the impedance calculation value.

10. The closed-loop acquisition device for inductance parameters of a permanent magnet motor for electric vehicles according to claim 9, characterized in that: The inductance parameter calculation module includes: The filter is configured to: filter the impedance calculation value; The divider is configured to obtain an inductance parameter based on the impedance calculation value after filtering.

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