Motor control circuit and control method therefor

Abstract

The present application provides a motor control circuit and a control method therefor. The motor control method comprises: obtaining a phase current of a motor; on the basis of the phase current of the motor, using a first motor angle estimation method to perform first channel motor angle estimation; on the basis of the phase current of the motor, using a second motor angle estimation method to perform second channel motor angle estimation; obtaining an operating state of the motor; on the basis of the operating state of the motor, switching between selecting a result of the first channel motor angle estimation or a result of the second channel motor angle estimation so as to perform drive control on the motor. According to the present application, appropriate switching of motor angle estimation control between two channels can be implemented, and the accuracy and dynamic response speed of motor / rotor position estimation are improved.

Description

Motor control circuit and its control method Cross-references to related applications

[0001] This patent application claims priority to Chinese Patent Application No. 202411642632.8, filed on November 15, 2024, entitled "Motor Control Circuit and Control Method Thereof", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of motor control, and in particular to a motor control circuit and its control method. Background Technology

[0003] In existing sensorless brushless DC motor control systems, rotor estimation is a crucial factor. Common motor angle estimation algorithms include sliding mode estimation, Luneburg estimation, and direct estimation. Among these, sliding mode and Luneburg estimation methods are computationally complex. While they offer high control precision and stability at high motor speeds compared to other algorithms, their computational complexity makes it difficult for the estimator to converge under unstable conditions such as motor startup and stall, hindering proper startup and accurate rotor position or speed estimation. In actual stall situations, the angle observer cannot detect it promptly, only responding when the overcurrent caused by the stall is detected. However, this approach can easily lead to motor overheating or burnout. Summary of the Invention

[0004] The purpose of this application is to provide a motor control circuit and control method thereof, which can solve at least one technical problem mentioned in the prior art.

[0005] One aspect of this application provides a motor control method. The motor control method includes: acquiring the phase current of a motor; performing a first-channel motor angle estimation based on the phase current using a first motor angle estimation method; performing a second-channel motor angle estimation based on the phase current using a second motor angle estimation method; acquiring the operating state of the motor; and, based on the operating state of the motor, switching between the result of the first-channel motor angle estimation and the result of the second-channel motor angle estimation to drive and control the motor.

[0006] Furthermore, the step of switching between the result of the first channel motor angle estimation and the result of the second channel motor angle estimation to drive the motor based on the operating state of the motor includes: when the motor is in a low-speed start-up phase where the speed is lower than a predetermined threshold, the result of the second channel motor angle estimation is used to control the motor to start.

[0007] Furthermore, the result of the first channel motor angle estimation includes a first estimated angle and a first estimated angular velocity obtained by estimating the first channel motor angle; the result of the second channel motor angle estimation includes a second estimated angle and a second estimated angular velocity obtained by estimating the second channel motor angle.

[0008] Further, the step of estimating the motor angle of the first channel based on the phase current of the motor using the first motor angle estimation method includes: estimating a first estimated angle change based on the phase current of the motor using the first motor angle estimation method; and obtaining a first estimated angle for the current control cycle based on the first estimated angle and the first estimated angle change from the previous control cycle. The step of estimating the motor angle of the second channel based on the phase current of the motor using the second motor angle estimation method includes: estimating a second estimated angle change based on the phase current of the motor using the second motor angle estimation method; and obtaining a second estimated angle for the current control cycle based on the second estimated angle and the second estimated angle change from the previous control cycle.

[0009] Furthermore, the step of switching between the result of the first channel motor angle estimation and the result of the second channel motor angle estimation to drive the motor based on the operating state of the motor includes: when the motor speed reaches a predetermined stable speed, comparing the magnitudes of the first estimated angle change and the second estimated angle change; when the error value between the first estimated angle change and the second estimated angle change is within a predetermined error range, switching from driving the motor based on the result of the second channel motor angle estimation to driving the motor based on the result of the first channel motor angle estimation.

[0010] Furthermore, the step of switching between the result of the first channel motor angle estimation or the result of the second channel motor angle estimation to drive the motor based on the operating state of the motor further includes: during the low-speed start-up phase, in each control cycle, replacing the first estimated angle of the previous control cycle with the second estimated angle of the current control cycle.

[0011] Furthermore, the step of estimating the second estimated angle change using the second motor angle estimation method includes: performing PI control with the objective that the component of the back electromotive force of the motor on the d-axis in the two-phase rotating coordinate system is zero in order to obtain the second estimated angle change.

[0012] Furthermore, the step of estimating the second estimated angle change based on the phase current of the motor using the second motor angle estimation method further includes: performing coordinate transformation on the three-phase current of the motor in a two-phase stationary coordinate system to obtain the d-axis current and q-axis current and the d-axis voltage of the motor in a two-phase rotating coordinate system; calculating the d-axis component of the motor's back electromotive force based on the d-axis current, the q-axis current, the d-axis voltage and the estimated angular velocity of the previous control cycle; and performing PI control on the deviation of the calculated d-axis component of the motor's back electromotive force from zero to obtain the second estimated angle change.

[0013] Furthermore, the step of estimating the first estimated angle change using the first motor angle estimation method includes estimating the first estimated angle change using the sliding diaphragm estimation method.

[0014] Furthermore, the step of estimating the first estimated angle change using the first motor angle estimation method includes estimating the first estimated angle change using the Luneberg estimation method.

[0015] Furthermore, the method also includes: when switching to a high-speed operation phase where the motor is driven and controlled based on the result of the first channel motor angle estimation, anomaly detection of the motor is performed based on the result of the second channel motor angle estimation.

[0016] Furthermore, the method also includes: when an abnormality is detected in the motor based on the result of the second channel motor angle estimation, the abnormality information is fed back to the motor engine control module, and the motor engine control module controls the shutdown of the motor.

[0017] Furthermore, the method also includes: when an abnormality is detected in the motor based on the result of the second channel motor angle estimation, directly controlling the motor to restart.

[0018] Another aspect of this application provides a motor control circuit. The motor control circuit includes at least one motor engine control module, a current acquisition module, a first coordinate transformation module, a second coordinate transformation module, a dual-channel motor angle estimation module, and a vector pulse width modulation module. The at least one motor engine control module is used to provide control signals to at least one corresponding motor. The current acquisition module is used to acquire the three-phase current of each motor in a three-phase stationary coordinate system. The first coordinate transformation module is connected to the output terminal of the current acquisition module and is used to perform a first coordinate transformation on the three-phase current of each motor. The second coordinate transformation module is connected to the first coordinate transformation module and is used to perform a second coordinate transformation on the output signal of the first coordinate transformation module. The dual-channel motor angle estimation module is connected to both the first and second coordinate transformation modules. The dual-channel motor angle estimation module is used to independently estimate the motor angle of each motor's two channels using two different motor angle estimation methods based on the output signals of the first and second coordinate transformation modules, and, based on the operating state of each motor, switches and selects one of the two channels of each motor to output the motor angle estimation result. The vector pulse width modulation module is connected to the output of the second coordinate transformation module. Based on the output signal of the second coordinate transformation module, it generates a spatial vector pulse width modulation signal for the corresponding motor and provides it to each motor engine control module.

[0019] Furthermore, the dual-channel motor angle estimation module includes a first speed estimation unit, a second speed estimation unit, and an angle estimation unit. The first speed estimation unit is used to estimate the first estimated angle change of each motor using a first motor angle estimation method based on the output signals of the first and second coordinate transformation modules. The second speed estimation unit is used to estimate the second estimated angle change of each motor using a second motor angle estimation method based on the output signals of the first and second coordinate transformation modules. The angle estimation unit is used to calculate the first and second estimated angles of each motor respectively based on the first and second estimated angle changes of each motor through time-division multiplexing, and, based on the operating state of each motor, switch between selecting either the first or second estimated angle of each motor as the output estimated angle of each motor.

[0020] Furthermore, the dual-channel motor angle estimation module also includes a speed feedback circuit. The speed feedback circuit is used to calculate the first estimated angular velocity and the second estimated angular velocity of each motor based on the first estimated angle change and the second estimated angle change of each motor, respectively, and to switch between the first estimated angular velocity or the second estimated angular velocity of each motor as the estimated angular velocity output of each motor based on the operating state of each motor.

[0021] Furthermore, the second speed estimation unit is used to perform PI control with the objective that the component of the back electromotive force of the motor on the d-axis in the two-phase rotating coordinate system is zero in order to obtain the second estimated angle change.

[0022] Further, the second speed estimation unit includes a two-Park transformation unit, a formula conversion module, an error calculator, and an error calculator. The second Park transformation unit transforms the two-phase voltages in the two-phase stationary coordinate system obtained by the second coordinate transformation module from the two-phase stationary coordinate system to a two-phase rotating coordinate system, thereby obtaining the d-axis current, q-axis current, and d-axis voltage of the motor in the two-phase rotating coordinate system. The formula conversion module calculates the d-axis component of the motor's back electromotive force based on the d-axis current and q-axis current in the two-phase rotating coordinate system obtained by the first coordinate transformation module, the d-axis voltage, and the estimated angular velocity from the previous control cycle. The error calculator calculates the deviation of the d-axis component of the motor's back electromotive force from zero. The error calculator performs PI control based on the deviation to obtain the second estimated angle change.

[0023] Furthermore, the first motor angle estimation method includes the sliding diaphragm estimation method.

[0024] Furthermore, the first motor angle estimation method includes the Luneberg estimation method.

[0025] Furthermore, the first coordinate transformation module includes a Clark transformation unit and a Park transformation unit connected to the output terminal of the Clark transformation unit. The Clark transformation unit is used to transform the three-phase current from a three-phase stationary coordinate system to a two-phase stationary coordinate system, so as to obtain the two-phase current in the two-phase stationary coordinate system. The Park transformation unit is used to transform the output signal of the Clark transformation unit from the two-phase stationary coordinate system to a two-phase rotating coordinate system, so as to obtain the d-axis current and q-axis current in the two-phase rotating coordinate system.

[0026] Furthermore, the second coordinate transformation module includes an inverse Park transformation unit, which is used to transform the two-phase voltage in the two-phase rotating coordinate system output by the first coordinate transformation module from the two-phase rotating coordinate system to the two-phase stationary coordinate system based on the motor estimated angle of the previous control cycle output by the dual-channel motor angle estimation module, so as to obtain the two-phase voltage in the two-phase stationary coordinate system.

[0027] The motor control circuit and control method of one or more embodiments of this application realize dual-channel motor angle estimation control by integrating the first motor angle estimation method and the second motor angle estimation method. Furthermore, it can be dynamically adjusted according to the operating state of the motor to realize reasonable switching between the two channels of motor angle estimation control, improve the accuracy of motor rotor position estimation and dynamic response speed, and thus improve the functionality and performance of the entire circuit in both directions. Attached Figure Description

[0028] Figure 1 is a structural block diagram of a motor control circuit according to an embodiment of this application.

[0029] Figure 2 is a structural diagram of the first coordinate transformation module and the second coordinate transformation module according to an embodiment of this application.

[0030] Figure 3 is a structural block diagram of a dual-channel motor angle estimation module according to an embodiment of this application.

[0031] Figure 4 shows the phase relationship between the rotor magnetic field position and the dq axis.

[0032] Figure 5 shows a direct E diagram of an embodiment of this application. d A schematic diagram of the phase-locked loop structure used in this method.

[0033] Figure 6 is a flowchart of a motor control method according to an embodiment of this application.

[0034] Figure 7 shows the estimation methods using the sliding membrane method and direct E. d A comparative diagram showing the changes in the estimated motor angle obtained by the estimation method when stall occurs. Detailed Implementation

[0035] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses consistent with some aspects of this application as detailed in the appended claims.

[0036] The motor control circuit and its control method of this application will now be described in detail with reference to the accompanying drawings. Unless otherwise specified, the features of the following embodiments and implementation methods can be combined with each other.

[0037] Figure 1 shows a structural block diagram of a motor control circuit 100 according to an embodiment of this application. As shown in Figure 1, the motor control circuit 100 according to an embodiment of this application may include at least one motor engine control module 110, a current acquisition module 120, a first coordinate transformation module 131, a second coordinate transformation module 132, a dual-channel motor angle estimation module 140, and a vector pulse width modulation module 150.

[0038] At least one motor engine control module 110 corresponds to at least one motor 200 and can provide control signals to the corresponding at least one motor 200. The control signals may include, for example, PWM signals.

[0039] The current acquisition module 120 can be used to acquire the three-phase current i of each motor 200 in the three-phase stationary (abc) coordinate system. a i b andi c In some embodiments, the current acquisition module 120 may include a sampling module 121 and a processor 122.

[0040] The sampling module 121 is connected to at least one motor engine control module 110. In one embodiment, to shorten the sampling time, the sampling module 121 can sample any two phases of the current (e.g., i) of each motor 200. a i b The third phase current of the motor 200 (e.g., i) is sampled. c The sampling module 121 can calculate the three-phase current i of each motor based on the known two-phase current by the processor 122. Alternatively, in other embodiments, the sampling module 121 can directly sample the three-phase current i of each motor. a i b andi c This application does not impose any restrictions on sampling.

[0041] The processor 122 is connected to the output terminal of the sampling module 121. In this embodiment, the processor 122 is implemented using a CPU (Central Processing Unit). However, this application is not limited to this; any module capable of data processing is applicable, including but not limited to an MPU (Micro Processor Unit). The sampling module 121 samples any two phase currents i from each motor. a i bIn the sampling embodiment, the processor 122 can sequentially read any two-phase current i of each motor 200 sampled by the sampling module 121. a i b Then, based on any two-phase current i of each motor 200 a i b The third-phase current i of each motor was calculated. c In the embodiment where the sampling module 121 samples the three-phase current of each motor, the processor 122 can directly and sequentially read the three-phase current i of each motor sampled by the sampling module 121. a i b andi c When there are multiple motors 200, the processor 122 outputs the three-phase current i of each motor 200. a i b andi c At the same time, the corresponding motor number can be output to facilitate the subsequent transformation of the current of each motor 200 and the control of each motor 200.

[0042] The first coordinate transformation module 131 is connected to the output terminal of the processor 122, and can transform the three-phase current i of each motor 200 in the three-phase stationary coordinate system. a i b andi c The first coordinate transformation is performed. The second coordinate transformation module 132 is connected to the first coordinate transformation module 131 and can perform the second coordinate transformation on the output signal of the first coordinate transformation module 131.

[0043] Figure 2 illustrates the structure of a first coordinate transformation module 131 and a second coordinate transformation module 132 according to an embodiment of this application. Referring to Figure 2, the first coordinate transformation module 131 includes a Clark transformation unit 1311 and a Park transformation unit 1312 connected to the output terminal of the Clark transformation unit 1311. The Clark transformation unit 1311 can transform the three-phase current i a i b andi c By transforming from the three-phase stationary (abc) coordinate system to the two-phase stationary (α-β) coordinate system, the two-phase current i in the two-phase stationary coordinate system can be obtained. α i β The Park converter unit 1312 can convert the output signal of the Clark converter unit 1311 (i.e., the two-phase current i) into the output signal of the Clark converter unit 1311. α i β By transforming from the two-phase stationary (α-β) coordinate system to the two-phase rotating (dq) coordinate system, the d-axis current i in the two-phase rotating coordinate system can be obtained. d and q-axis current i qFurthermore, the dual-channel motor angle estimation module 140 estimates the motor's estimated angular velocity from the previous control cycle. With angular velocity reference value ω ref The difference is used to obtain the q-axis reference current i through external PI control. qref d-axis reference current i dref It can be a fixed value, then the d-axis current i d With d-axis reference current i dref The difference between them, and the q-axis current i q With q-axis reference current i qref The difference between them is used to obtain the d-axis voltage u in the two-phase rotating coordinate system through internal PI control. d and q-axis voltage u q .

[0044] The second coordinate transformation module 132 may include an inverse Park transformation unit 1321, which can estimate the motor angle based on the previous control cycle output by the dual-channel motor angle estimation module 140. The two-phase voltage u in the two-phase rotating coordinate system output by the first coordinate transformation module 131 d u q By transforming from a two-phase rotating coordinate system to a two-phase stationary coordinate system, the two-phase voltage u in the two-phase stationary coordinate system can be obtained. α u β .

[0045] Referring again to Figure 1, the dual-channel motor angle estimation module 140 is connected to the first coordinate transformation module 131 and the second coordinate transformation module 132, respectively. The dual-channel motor angle estimation module 140 can independently estimate the motor angle of the two channels using two different motor angle estimation methods based on the output signals of the first coordinate transformation module 131 and the second coordinate transformation module 132. Based on the motor's operating state, it can switch and select one of the two channels to output the motor angle estimation result.

[0046] Specifically, the dual-channel motor angle estimation module 140 can obtain the two-phase current i in the two-phase stationary coordinate system of the current control cycle from the first coordinate transformation module 131. α i β And obtain the two-phase voltage u in the two-phase stationary coordinate system of the previous control cycle from the second coordinate transformation module 132. α u β Two motor angle estimation methods were used to independently estimate the angles of the two channels, ultimately yielding the estimated motor angles for the output. And estimating angular velocity This allows us to obtain the motor rotor position and speed.

[0047] The vector pulse width modulation module 150 is connected to the output terminal of the second coordinate transformation module 132. The vector pulse width modulation module 150 can be based on the output signal of the second coordinate transformation module 132, i.e., the two-phase voltage u in the two-phase stationary coordinate system. α u β This generates a space vector pulse width modulation (SVPWM) signal for the corresponding motor and provides it to each motor engine control module 110.

[0048] Figure 3 illustrates a structural block diagram of a dual-channel motor angle estimation module 140 according to an embodiment of this application. As shown in Figure 3, in some embodiments, the dual-channel motor angle estimation module 140 of this application may include a first speed estimation unit 141, a second speed estimation unit 142, and an angle estimation unit 143.

[0049] The first velocity estimation unit 141 can estimate the velocity based on the output signal of the first coordinate transformation module 131 (e.g., the two-phase current i in a two-phase stationary coordinate system). α i β The output signal of the second coordinate transformation module 132 (i.e., the two-phase voltage u in the two-phase stationary coordinate system) α u β The first estimated angle change of each motor was obtained by using the first motor angle estimation method.

[0050] The second velocity estimation unit 142 can estimate the velocity based on the output signal of the first coordinate transformation module 131 (e.g., the two-phase current i in the two-phase stationary coordinate system). α i β The output signal of the second coordinate transformation module 132 (i.e., the two-phase voltage u in the two-phase stationary coordinate system) α u β The second estimated angle change of each motor is estimated using the second motor angle estimation method.

[0051] The angle estimation unit 143 can estimate the angle change of each motor 200 respectively. Second estimated angle change The first estimated angle of each motor (200°) is calculated using a time-sharing multiplexing method. Second estimation angle Based on the operating status of each motor 200, the first estimated angle of each motor 200 is switched and selected. Or a second estimation angle As the estimated angle for each motor 200 Output.

[0052] The dual-channel motor angle estimation module 140 also includes a speed feedback circuit 144. The speed feedback circuit 144 can adjust the speed based on the first estimated angle change of each motor 200. Second estimated angle change The first estimated angular velocity of each motor was calculated. Second estimated angular velocity Based on the operating status of each motor 200, the first estimated angular velocity of each motor 200 is selected. Or the second estimated angular velocity As the estimated angular velocity of each motor Output.

[0053] In some embodiments, the first motor angle estimation method of this application is a high-precision estimation method, which may include, but is not limited to, sliding film estimation, Luneburg estimation, etc.; the second motor angle estimation method may be referred to as direct E in this application. d The estimation method, namely, taking the back electromotive force of motor 200 as the d-axis component E in a two-phase rotating coordinate system. d An estimation method for control targets.

[0054] Figure 4 illustrates the relationship between the rotor magnetic field position and the phase of the dq axis. In qd-axis control, when the component of the motor's back electromotive force on the d-axis is zero, i.e., E... d When the torque is 0, the control efficiency is high and the energy loss is minimal. Therefore, the direct E of this application... d The control objective of the estimation method is to make the angle between the magnetic field direction and the d-axis approach 0, i.e., E d The value approaches 0.

[0055] Therefore, the second speed estimation unit 142 of this application can use the back electromotive force of the motor in the d-axis component E in a two-phase rotating coordinate system. d PI control is performed with a target of zero to obtain the second estimated angle change.

[0056] Figure 5 illustrates a direct E-model of one embodiment of this application. d A schematic diagram of the phase-locked loop structure used in the method is shown in Figure 5. The second speed estimation unit 142 may include a second Park transformation unit 1421, a formula conversion module 1422, an error calculator 1423, and a PI controller 1424. The second Park transformation unit 1421 can convert the two-phase voltage u in the two-phase stationary coordinate system obtained by the second coordinate transformation module 132. α u β By transforming from a two-phase stationary coordinate system to a two-phase rotating coordinate system, the d-axis voltage u of motor 200 in the two-phase rotating coordinate system can be obtained. d and q-axis voltage uq The formula conversion module 1422 can be based on the d-axis current i in the two-phase rotating coordinate system obtained by the first coordinate transformation module 131. d and q-axis current i q d-axis voltage u d and the estimated angular velocity of the previous control cycle The back electromotive force E of motor 200 in the d-axis was calculated. d The error calculator 1423 can calculate the d-axis component E of the back electromotive force of motor 200. d The deviation from zero. The PI controller 1424 can perform PI control based on the deviation to obtain a second estimated angle change.

[0057] The second velocity estimation unit 142 can estimate the change in the second estimated angle. The output is sent to the angle estimation unit 143, which then outputs the estimated angle of the motor. To the second Park transformation unit 1421. Thus, the direct E of this application is formed. d The phase-locked loop structure used in the method.

[0058] The motor control circuit 100 of this application integrates a first motor angle estimation method and a second motor angle estimation method to achieve dual-channel motor angle estimation control. Furthermore, it can be dynamically adjusted according to the operating status of the motor 200 to achieve reasonable switching between the two channels of motor angle estimation control, thereby improving the accuracy of motor rotor position estimation and dynamic response speed. The motor control circuit 100 of this application has achieved a two-way improvement in both function and performance.

[0059] This application also provides a motor control method. Figure 6 illustrates a flowchart of a motor control method according to an embodiment of this application. As shown in Figure 6, the motor control method according to an embodiment of this application may include steps S1 to S5.

[0060] In step S1, the phase current of the motor is obtained.

[0061] In step S2, the first channel motor angle can be estimated using the first motor angle estimation method based on the phase current of the motor.

[0062] In some embodiments, step S2 may further include steps S21 to S23.

[0063] In step S21, the first estimated angle change can be estimated based on the phase current of the motor using the first motor angle estimation method.

[0064] The first method for estimating the motor angle can employ high-precision estimation methods such as sliding membrane estimation and Luneburg estimation.

[0065] In step S22, the first estimated angle can be determined based on the previous control cycle. The first estimated angle change obtained in step S21 To obtain the first estimated angle of the current control cycle

[0066] In step S23, the first estimated angle change obtained in step S21 can be used as a basis. Obtain the first estimated angular velocity

[0067] In step S3, the second channel motor angle can be estimated using the second motor angle estimation method based on the phase current of the motor.

[0068] In some embodiments, step S3 may further include steps S31 to S33.

[0069] In step S31, the second estimated angle change can be estimated using the second motor angle estimation method based on the phase current of motor 200.

[0070] The second motor angle estimation method can adopt the direct E method referred to in this application. d The estimation method, namely, taking the back electromotive force of motor 200 as the d-axis component E in a two-phase rotating coordinate system. d An estimation method for control targets.

[0071] Therefore, in step S31, the back electromotive force of motor 200 in the d-axis component E in the two-phase rotating coordinate system can be determined. d PI control is performed with a target of zero to obtain the second estimated angle change.

[0072] Specifically, the three-phase current i of motor 200 in a two-phase stationary coordinate system a i b andi c By performing a coordinate transformation, the d-axis current i of motor 200 in a two-phase rotating coordinate system can be obtained. d and q-axis current i q and the d-axis voltage u in a two-phase rotating coordinate system d Based on d-axis current i d q-axis current i q d-axis voltage u d and the estimated angular velocity of the previous control cycle The back electromotive force (EMF) component E of the motor along the d-axis was calculated.d The calculated back electromotive force of the motor in the d-axis component E d By applying PI control to the deviation from zero, a second estimated angle change can be obtained.

[0073] In step S32, the second estimated angle can be determined based on the previous control cycle. The second estimated angle change obtained in step S31 To obtain the second estimation angle of the current control cycle

[0074] In step S33, the second estimated angle change obtained in step S31 can be used as a basis. The second estimated angular velocity was obtained.

[0075] In step S4, the operating status of the motor is obtained.

[0076] In step S5, based on the motor's operating state, the motor is driven by switching between the result of the first channel motor angle estimation and the result of the second channel motor angle estimation.

[0077] The result of the first channel motor angle estimation includes the first estimated angle obtained by estimating the first channel motor angle. and the first estimated angular velocity The result of the second-channel motor angle estimation includes the second estimated angle obtained through the second-channel motor angle estimation. Second estimated angular velocity

[0078] In some embodiments, step S5, which involves switching between the result of the first channel motor angle estimation and the result of the second channel motor angle estimation to drive the motor based on the motor's operating state, may include step S51.

[0079] In step S51, when the motor is in a low-speed start-up phase where the speed is below a predetermined threshold, the motor start-up is controlled by the result of the second channel motor angle estimation.

[0080] In some embodiments, step S5, which involves switching between the result of the first channel motor angle estimation and the result of the second channel motor angle estimation to drive the motor based on the motor's operating state, may further include steps S52 and S53.

[0081] In step S52, it is determined whether the motor speed has reached the predetermined speed for stable operation. If the result of the determination is "yes", the process proceeds to step S53. Otherwise, it returns to step S52 to continue monitoring and determining.

[0082] In step S53, when the motor speed reaches a predetermined stable operating speed, the first estimated angle change is compared. Second estimated angle change The size is determined, and then proceed to step S54.

[0083] In step S54, the first estimated angle change is determined. Second estimated angle change Check whether the error value is within the predetermined error range. If the result of the judgment is "yes", the process proceeds to step S55. Otherwise, return to step S54 to continue the judgment.

[0084] In step S55, when the first estimated angle change... Second estimated angle change When the error value between the two is within the predetermined error range, the motor drive control will be switched from the result of the second channel motor angle estimation to the result of the first channel motor angle estimation.

[0085] Considering that in actual control, when the two channels are estimated independently, the motor running speed (i.e., the estimated angle change calculated from the two channels' motor angles) may differ. and While the estimated positions of the two motors are consistent, the large error in the motor position estimation means that switching directly between the two channels for motor angle estimation control may cause jitter. Therefore, in some embodiments, to maintain consistency between the estimated positions of the two motors, step S5, which involves switching between the result of the first channel motor angle estimation and the result of the second channel motor angle estimation for motor drive control based on the motor's operating state, may further include step S56.

[0086] In step S56, during the low-speed start-up phase, within each control cycle, the second estimated angle of the current control cycle is used. To replace the first estimation angle of the previous control cycle

[0087] That is, during the low-speed start-up phase of the motor, the following can be obtained: Direct E d Estimation control: High-precision estimation control:

[0088] Thus, it is possible to achieve direct E d A smooth transition from estimation-based control to high-precision estimation-based control is achieved to avoid jitter.

[0089] In some embodiments, the motor control method of this application may further include step S57.

[0090] In step S57, when switching to the high-speed operation stage where the motor is driven and controlled based on the motor angle estimation result of the first channel, the motor anomaly detection can be performed based on the motor angle estimation result of the second channel.

[0091] When the motor is running at high speed, the following can be obtained: Direct E d Estimation control: High-precision estimation control:

[0092] During motor startup, high-precision estimation methods and direct E d The estimation method estimates the two channels independently. When the estimated values ​​are... and When the values ​​are close to equal, switch the motor angle estimation control to the high-precision estimation channel control. No need to replace it with The value estimated directly using the high-precision estimation channel is now calculated independently by both channels. The high-precision estimation channel is responsible for controlling stable operation at high speeds. d The estimation channel is responsible for detecting whether the motor is operating normally.

[0093] Therefore, when the motor is operating at high speed, the motor control method of this application can be based on the second estimated angle of the current control cycle obtained by estimating the motor angle of the second channel. This enables the system to perform error detection, allowing for the detection of motor anomalies.

[0094] In some embodiments, the motor control method of this application may further include step S58.

[0095] In step S58, when an abnormality is detected in the motor based on the result of the second channel motor angle estimation, the abnormality information is fed back to the motor engine control module 110, which then controls the motor to shut down; or, when an abnormality is detected in the motor based on the result of the second channel motor angle estimation, the motor is directly controlled to restart.

[0096] Figure 7 illustrates the use of the sluice plate estimation method and direct E. d A comparative diagram showing the change of the estimated motor angle θ obtained by the estimation method when the motor rotor is stalled. As shown in Figure 7, actual testing revealed that the observer of the sliding film estimation method exhibits non-convergence when the motor rotor is stalled; while the direct E-method of this application... dThe estimated angle θ of the motor calculated by the estimation method will rise rapidly and overflow. Therefore, by observing the overflow phenomenon, the system can quickly shut down or restart the motor according to the actual application requirements.

[0097] The high-precision estimation method has a complex calculation formula and high control precision, especially with its good noise reduction effect when the motor is running at high speed. However, when the motor is running under unstable conditions such as low-speed start-up or stall, the observer of the high-precision estimation method will exhibit non-convergence, that is, the observer of the high-precision estimation method cannot estimate the correct angle / speed information.

[0098] In direct E d Among the observers using estimation methods, the calculation formula is relatively simple, but its control precision is not as good as that of high-precision estimation methods. Its noise reduction effect is also relatively poor when the motor is running at high speeds. However, direct E... d The estimator is not significantly affected by the motor's own parameters, has a fast dynamic response, and can directly start the motor under static or tailwind conditions. Therefore, direct E d The estimation method has significant advantages in direct closed-loop starting. However, when the motor rotor is stalled, direct E... d The estimated angle of the motor calculated by the estimation method rises rapidly and overflows.

[0099] The motor control method of this application combines the above high-precision estimation method and direct E. d The two estimation methods each have their own advantages, realizing dual-channel motor angle estimation control. Furthermore, it can be dynamically adjusted according to the motor's operating status, achieving reasonable switching between the two channels of motor angle estimation control, improving the accuracy of motor rotor position estimation and dynamic response speed, and comprehensively enhancing the control system's control efficiency, safety, and stability.

[0100] The motor control circuit and control method provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the motor control circuit and control method of this application. The descriptions of the embodiments above are only for helping to understand the core ideas of this application and are not intended to limit this application. It should be noted that those skilled in the art can make several improvements and modifications to this application without departing from the spirit and principles of this application, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method of controlling an electric machine, characterized by, include: Obtain the phase current of the motor; The first channel motor angle is estimated using the first motor angle estimation method based on the phase current of the motor. The second channel motor angle is estimated using the second motor angle estimation method based on the phase current of the motor. Obtain the operating status of the motor; Based on the operating status of the motor, the motor can be driven and controlled by switching between the result of the first channel motor angle estimation and the result of the second channel motor angle estimation.

2. The motor control method of claim 1, wherein, The step of switching between the motor angle estimation result of the first channel and the motor angle estimation result of the second channel based on the motor's operating state to drive the motor includes: When the motor is in a low-speed start-up phase where the speed is below a predetermined threshold, the motor start-up is controlled by the result of the second channel motor angle estimation.

3. The motor control method of claim 2, wherein, The result of the first channel motor angle estimation includes a first estimated angle and a first estimated angular velocity obtained by estimating the first channel motor angle; the result of the second channel motor angle estimation includes a second estimated angle and a second estimated angular velocity obtained by estimating the second channel motor angle.

4. The motor control method of claim 3, wherein, The step of estimating the motor angle of the first channel based on the phase current of the motor using the first motor angle estimation method includes: The first estimated angle change is obtained by estimating the phase current of the motor using the first motor angle estimation method. The first estimated angle for the current control cycle is obtained based on the first estimated angle of the previous control cycle and the change in the first estimated angle. The step of estimating the second-channel motor angle using the second motor angle estimation method based on the phase current of the motor includes: The second estimated angle change is obtained by estimating the phase current of the motor using the second motor angle estimation method. The second estimated angle for the current control cycle is obtained based on the second estimated angle of the previous control cycle and the change in the second estimated angle.

5. The motor control method of claim 4, wherein, The step of switching between the motor angle estimation result of the first channel and the motor angle estimation result of the second channel based on the motor's operating state to drive the motor includes: When the motor reaches a predetermined speed and runs stably, the magnitudes of the first estimated angle change and the second estimated angle change are compared. When the error between the first estimated angle change and the second estimated angle change is within a predetermined error range, the drive control of the motor will be switched from being based on the result of the second channel motor angle estimation to being based on the result of the first channel motor angle estimation.

6. The motor control method of claim 5, wherein, The step of switching between the result of the first channel motor angle estimation and the result of the second channel motor angle estimation to drive the motor based on the operating state of the motor further includes: During the low-speed start-up phase, in each control cycle, the second estimated angle of the current control cycle is used to replace the first estimated angle of the previous control cycle.

7. The motor control method of claim 4, wherein, The method of estimating the second estimated angle change using the second motor angle estimation method includes: The second estimated angle change is obtained by performing PI control with the objective that the component of the back electromotive force of the motor on the d-axis in the two-phase rotating coordinate system is zero.

8. The motor control method of claim 7, wherein, The step of estimating the second estimated angle change based on the phase current of the motor using the second motor angle estimation method further includes: The three-phase current of the motor in the two-phase stationary coordinate system is transformed to obtain the d-axis current and q-axis current of the motor in the two-phase rotating coordinate system and the d-axis voltage in the two-phase rotating coordinate system. Based on the d-axis current, the q-axis current, the d-axis voltage, and the estimated angular velocity of the previous control cycle, the component of the back electromotive force of the motor in the d-axis is calculated. The deviation of the calculated back electromotive force of the motor on the d-axis from zero is subjected to PI control to obtain the second estimated angle change.

9. The motor control method of claim 4, wherein, The first estimated angle change obtained by using the first motor angle estimation method includes: The change in the first estimated angle is obtained using the synovial estimation method.

10. The motor control method of claim 4, wherein, The first estimated angle change obtained by using the first motor angle estimation method includes: The change in the first estimated angle was obtained using the Lundberg estimation method.

11. The motor control method of any one of claims 1 to 10, wherein, Also includes: When switching to the high-speed operation phase where the motor is driven and controlled based on the motor angle estimation result of the first channel, the motor is subjected to anomaly detection based on the motor angle estimation result of the second channel.

12. The motor control method of claim 11, wherein, Also includes: When an abnormality is detected in the motor based on the result of the motor angle estimation in the second channel, the abnormality information is fed back to the motor engine control module, which then controls the motor to shut down.

13. The motor control method of claim 11, wherein, Also includes: When an abnormality is detected in the motor based on the result of the motor angle estimation in the second channel, the motor is directly controlled to restart.

14. An electric motor control circuit, characterized by include: At least one motor engine control module is provided for providing control signals to at least one corresponding motor; The current acquisition module is used to acquire the three-phase current of each motor in the three-phase stationary coordinate system; The first coordinate transformation module is connected to the output terminal of the current acquisition module and is used to perform the first coordinate transformation on the three-phase current of each motor. The second coordinate transformation module is connected to the first coordinate transformation module and is used to perform a second coordinate transformation on the output signal of the first coordinate transformation module. A dual-channel motor angle estimation module is connected to the first coordinate transformation module and the second coordinate transformation module respectively. The dual-channel motor angle estimation module is used to independently estimate the motor angle of each motor in two channels based on the output signals of the first coordinate transformation module and the second coordinate transformation module using two different motor angle estimation methods. Based on the operating status of each motor, the module switches and selects one of the two channels of each motor to output the motor angle estimation result. The vector pulse width modulation module is connected to the output of the second coordinate transformation module. Based on the output signal of the second coordinate transformation module, it generates the corresponding spatial vector pulse width modulation signal for the motor and provides it to each motor engine control module.

15. The motor control circuit of claim 14, wherein, The dual-channel motor angle estimation module includes a first speed estimation unit, a second speed estimation unit, and an angle estimation unit, wherein... The first speed estimation unit is used to estimate the first estimated angle change of each motor based on the output signal of the first coordinate transformation module and the output signal of the second coordinate transformation module using the first motor angle estimation method. The second speed estimation unit is used to estimate the second estimated angle change of each motor based on the output signal of the first coordinate transformation module and the output signal of the second coordinate transformation module using the second motor angle estimation method; The angle estimation unit is used to calculate the first estimated angle and the second estimated angle of each motor by time-division multiplexing based on the first estimated angle change and the second estimated angle change of each motor, respectively, and to switch between the first estimated angle or the second estimated angle of each motor as the estimated angle output of each motor based on the operating status of each motor.

16. The motor control circuit of claim 15, wherein, The dual-channel motor angle estimation module also includes a speed feedback circuit. The speed feedback circuit is used to calculate the first estimated angular velocity and the second estimated angular velocity of each motor based on the first estimated angle change and the second estimated angle change of each motor, respectively, and to switch between the first estimated angular velocity or the second estimated angular velocity of each motor as the estimated angular velocity output of each motor based on the operating state of each motor.

17. The motor control circuit of claim 15, wherein, The second speed estimation unit is used to perform PI control with the objective that the component of the back electromotive force of the motor on the d-axis in the two-phase rotating coordinate system is zero, so as to obtain the second estimated angle change.

18. The motor control circuit of claim 17, wherein, The second velocity estimation unit includes: The second Park transformation unit is used to transform the two-phase voltage in the two-phase stationary coordinate system obtained by the second coordinate transformation module from the two-phase stationary coordinate system to the two-phase rotating coordinate system, so as to obtain the d-axis current, q-axis current and d-axis voltage of the motor in the two-phase rotating coordinate system. The formula conversion module is used to calculate the component of the back electromotive force of the motor in the d-axis based on the d-axis current and q-axis current in the two-phase rotating coordinate system obtained by the first coordinate transformation module, the d-axis voltage, and the estimated angular velocity of the previous control cycle. An error calculator is used to calculate the deviation of the back electromotive force of the motor along the d-axis from zero; and A PI controller is used to perform PI control based on the deviation to obtain the second estimated angle change.

19. The motor control circuit of claim 15, wherein, The first motor angle estimation method includes the sliding diaphragm estimation method.

20. The motor control circuit of claim 15, wherein, The first motor angle estimation method includes the Luneberg estimation method.

21. The motor control circuit of any one of claims 14 to 20, wherein, The first coordinate transformation module includes a Clark transformation unit and a Park transformation unit connected to the output of the Clark transformation unit, wherein, The Clark transformation unit is used to transform the three-phase current from the three-phase stationary coordinate system to the two-phase stationary coordinate system, so that the two-phase current is in the two-phase stationary coordinate system. The Park transformation unit is used to transform the output signal of the Clark transformation unit from a two-phase stationary coordinate system to a two-phase rotating coordinate system to obtain the d-axis current and q-axis current in the two-phase rotating coordinate system.

22. The motor control circuit of any one of claims 14 to 20, wherein, The second coordinate transformation module comprises an inverse Park transformation unit, The inverse Park transformation unit is configured to transform two-phase voltages in a two-phase rotating coordinate system output by the first coordinate transformation module from the two-phase rotating coordinate system to a two-phase static coordinate system based on a motor estimated angle of a previous control period output by the dual-channel motor angle estimation module, so as to obtain two-phase voltages in the two-phase static coordinate system.

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