TWI760228B - Motor control method - Google Patents

Abstract

The present disclosure relates to a motor control method, including the following steps: adjusting a voltage component of an estimated voltage command to a steady-state voltage value; performing a coordinate axis conversion on the other voltage component of the estimated voltage command and the steady-state voltage value, and generating a three-phase excitation current to make a synchronous motor rotate to the rotating position and stop; calculating an estimated current signal; when determining that the current component is not maintained at a steady-state current value, calculating the estimated value of the stop position, and adjusting the other voltage component of the estimated voltage command; when determining that the current component maintains the steady-state current value, calculating an effective inductance of the synchronous motor according to the steady-state voltage value, the other voltage component, the steady-state current value, and the other current component of the estimated current signal.

Description

motor control method

The present disclosure relates to a motor control method, especially for calculating the inductance of a magnet-assisted synchronous reluctance motor.

When there is no position sensor (or encoder) to drive the motor, a large number of motor parameters need to be used to estimate the angle of the rotating shaft so that the motor can be driven accurately. In the traditional technology, the inverter used to drive the motor generates the corresponding stator magnetic field through appropriate control of the stator current of the motor, and keeps the stator magnetic field and the rotor magnetic field orthogonal to maintain high-efficiency operation. Generally speaking, the conventional control device estimates the position of the rotor of the motor according to the driving voltage, driving current and motor parameters, and appropriately adjusts the control command according to the rotor position to keep the directions of the stator magnetic field and the rotor magnetic field orthogonal to each other . Therefore, how to correctly calculate the parameters of the motor has become an important issue.

Among them, in the field of motor control, the inductance of the motor (including: direct-axis inductance and quadrature-axis inductance) is a very important motor parameter. Among them, a permanent magnet assisted synchronous reluctance motor (PMaSynRM, hereinafter referred to as a reluctance motor) is a rotor structure using both a permanent magnet material and a magnetic conductive material (eg, silicon steel sheet, etc.) as the motor. However, due to the characteristics of the rotor structure of such a motor, the inductance of the motor is related to the rotor position. Under the traditional self-learning method of inductance parameters, the rotor position of the reluctance motor is difficult to precisely align with the set angle, so it is difficult to accurately calculate the inductance of the motor. Therefore, for the current conventional technology, it is difficult to accurately calculate the inductance of the reluctance motor (eg, direct-axis inductance, quadrature-axis inductance).

The present disclosure provides a motor control method for calculating the inductance of the motor. Thereby, the aforementioned problems are solved.

The present disclosure relates to a motor control method for a position sensorless synchronous motor. The motor control method includes: adjusting the voltage component of the estimated voltage command to a steady-state voltage value; performing coordinate axis transformation on another voltage component of the estimated voltage command and the steady-state voltage value to generate a two-axis voltage command; according to the DC excitation voltage command and two-axis voltage command, generate three-phase excitation current to drive the synchronous motor to rotate to the rotating position and stop; extract the three-phase excitation current to calculate an estimated current signal, wherein the current component of the estimated current signal corresponds to the steady-state voltage When it is judged that the current component is not maintained at the steady-state current value, the estimated value of the rotational position is calculated according to the estimated current signal; according to the estimated value of the rotational position, another voltage component of the estimated voltage command is adjusted so that the corresponding stable The current component of the state voltage value is maintained at the steady state current value; when it is determined that the current component maintains the steady state current value, according to the steady state voltage value, another voltage component of the estimated voltage command, the steady state current value and the difference of the estimated current signal. Another current component, calculates the effective inductance of the synchronous motor.

The present disclosure also relates to a motor control method for a synchronous motor. The position sensor is coupled to the synchronous motor. The motor control method includes: adjusting the voltage component of the estimated voltage command to a steady-state voltage value; performing coordinate axis transformation on another voltage component of the estimated voltage command and the steady-state voltage value to generate a two-axis voltage command; according to the DC excitation voltage command and two-axis voltage command, generate three-phase excitation current to drive the synchronous motor to rotate to the rotating position and stop; extract the three-phase excitation current to calculate the estimated current signal, wherein the current component of the estimated current signal corresponds to the steady-state voltage value ; When it is determined that the current component is not maintained at the steady-state current value, the measured value of the rotational position is obtained by the position sensor; according to the measured value of the rotational position, another voltage component of the estimated voltage command is adjusted so that the corresponding stable The current component of the state voltage value is maintained at the steady state current value; when it is determined that the current component maintains the steady state current value, according to the steady state voltage value, another voltage component of the estimated voltage command, the steady state current value and the difference of the estimated current signal. Another current component, calculates the effective inductance of the synchronous motor.

In the present disclosure, the position of the rotor of the motor is estimated according to the feedback current signal containing the angle error information, and the angle of the estimated coordinate axis is adjusted according to the estimated rotor position, and the voltage vector of the inductance test is corrected accordingly, Until the position error between the estimated coordinates and the rotational position of the rotor converges within the error range. Accordingly, the motor control device can estimate the motor parameters at the correct rotor position according to the corrected estimated coordinate axis, so as to facilitate the precise control of the synchronous motor.

Several embodiments of the present invention will be disclosed in the drawings below, and for the sake of clarity, many practical details will be described together in the following description. It should be understood, however, that these practical details should not be used to limit the invention. That is, in some embodiments of the invention, these practical details are unnecessary. In addition, for the purpose of simplifying the drawings, some well-known structures and elements will be shown in a simple and schematic manner in the drawings.

FIG. 1A is a schematic diagram of coordinate axis transformation according to a conventional technique. In the field of general motor control (including the control of reluctance motors), the motion state of the motor is represented by the transformation operation of the coordinate axes, as shown in Figure 1A. Generally speaking, the d-axis and the q-axis are synchronous coordinate axes, which are used to represent the rotor position of the motor. Therefore, when the rotational speed of the reluctance motor is zero, the synchronous coordinate axis of the reluctance motor is expressed by equation (1) as follows:

(1)

(1)

In equation (1), Vd is the d-axis voltage, Vq is the q-axis voltage, id is the d-axis current, iq is the q-axis current, Ld is the d-axis inductance, Lq is the q-axis inductance, and rs is the reluctance motor. the stator resistance.

As shown in Fig. 1A, the delta axis and the gamma axis are the estimated coordinate axes, which are used to represent the set rotor position of the motor (usually the rotor position determined by the computer or the controller) or the estimated rotor position. The α-axis and the β-axis are static coordinate axes, which are used to represent the stator position of the motor. The a-axis, b-axis, and c-axis represent the three-phase coordinate axes of the motor.

Due to the structural characteristics of the reluctance motor, when the rotor of the control reluctance motor is stopped, when Θa represents the actual position Θa of the rotor of the motor (or the angular difference between the d-axis of the synchronous coordinate axis and the a-axis of the three-phase coordinate axis), There is a significant angular error between the estimated coordinate axis and the synchronized coordinate axis. Therefore, when Equation (1) is converted to the estimated axes, Equation (2) is obtained as follows:

(2)

(2)

In equation (2), Vδ represents the delta-axis voltage, Vγ represents the γ-axis voltage, iδ represents the delta-axis current, iγ represents the γ-axis current, Ld represents the d-axis inductance, Lq represents the q-axis inductance, and rs represents the reluctance motor The stator resistance of , Θer represents the angular error between the motor synchronous coordinate axis and the estimated coordinate axis.

As known from equation (2), equation (2) contains the component of actual position Θa because the synchronous axis representing the motor rotor is not aligned with the estimated axis. In the case of no position sensor, it is difficult to obtain the actual position Θa of the rotor, so the traditional motor control method without position sensor cannot accurately estimate the d-axis inductance Ld (or direct-axis inductance of the reluctance motor) Quantity Ld) and q-axis inductance (or quadrature-axis inductance Lq), so that the control efficiency of the motor is greatly reduced. As shown in FIG. 1B , the present disclosure proposes a motor control device and a control method thereof. The estimated value Θv of the actual position Θa of the rotor is estimated by calculation to adjust the position of the estimated coordinate axes (delta axis and gamma axis). to reduce the component of the actual rotor position Θa. Thereby, the above-mentioned problems are solved. Although there is an angular error Θer between the estimated value Θv and the actual position Θa of the rotor, the present disclosure can make the angular error Θer approach zero by adjusting the estimated value Θv. The implementation method of the present disclosure will be described in detail below.

FIG. 2 is a schematic diagram of a motor control device 100 according to some embodiments of the present disclosure. The motor control device 100 is applied to a synchronous motor 200 without a position sensor. It is particularly noted that the synchronous motor 200 refers to a magnet-assisted synchronous reluctance motor, but the present disclosure is not limited thereto.

The motor control device 100 (or inverter) includes a control arithmetic unit 110 , a driving arithmetic unit 120 and a feedback arithmetic unit 130 . The control operation unit 110 is used to receive the estimated voltage command (including the estimated direct-axis voltage Vδ and the estimated quadrature-axis voltage Vγ), and generate biaxial voltage commands (including the first voltage component Vα and the second voltage component) accordingly Vβ) to the driving operation unit 120 . According to the two-axis voltage command, the driving operation unit 120 provides the three-phase excitation currents Ia, Ib, and Ic to the synchronous motor 200 . The feedback computing unit 130 captures the three-phase excitation currents Ia, Ib, and Ic of the synchronous motor 200 . Next, the feedback operation unit 130 generates a feedback signal to the control operation unit 110 according to the three-phase excitation currents Ia, Ib, and Ic. The control arithmetic unit 110 calculates the direct-axis inductance or the quadrature-axis inductance of the synchronous motor 200 according to the aforementioned feedback signal. In this embodiment, the two-axis voltage commands (Vα, Vβ) represent the stationary coordinate axis, so the first voltage component Vα is also called the α-axis voltage of the stationary coordinate axis, and the second voltage component Vβ is also called the β-axis voltage of the stationary coordinate axis. , but the present disclosure is not limited thereto. It should be noted that, in an embodiment, the estimated direct-axis voltage Vδ, the estimated quadrature-axis voltage Vγ, the first voltage component Vα, and the second voltage component Vβ are all high-frequency AC signals, but the disclosure is not limited thereto. .

Please refer to FIG. 2 , FIG. 3A and FIG. 3B together below to describe various embodiments of the present disclosure. The present disclosure provides a motor control method 300 , and the motor control method 300 is suitable for a synchronous motor 200 without a position sensor. The motor control method 300 is executed by the motor control device 100 , and the motor control method 300 includes steps S301 - S308 . In addition, step S303 further includes steps S3031 to S3034.

In step S301 , the control operation unit 110 adjusts a voltage component of the estimated voltage command (including the estimated direct-axis voltage Vδ and the estimated quadrature-axis voltage Vγ) to a steady-state voltage value. As shown in FIG. 2 , in order to calculate the quadrature inductance Lq more accurately, the control unit 110 can adjust the estimated quadrature voltage Vδ to be a steady-state voltage value, and maintain the estimated quadrature voltage Vγ as a high-frequency AC signal. Or, in order to calculate the direct-axis inductance Ld more accurately, the control operation unit 110 may adjust the estimated direct-axis voltage Vγ to be a steady-state voltage value, and maintain the estimated direct-axis voltage Vδ to be a high-frequency AC signal. In a preferred embodiment, the steady-state voltage value may be designed to be zero, but the present disclosure is not limited thereto.

In step S302, coordinate axis transformation is performed on another voltage component of the estimated voltage command and the steady-state voltage value to generate a two-axis voltage command. For example, as shown in FIG. 2, the control operation unit 110 includes a coordinate converter 111 and an inductance operation unit 112, and the control operation unit 110 adjusts the estimated quadrature-axis voltage Vγ to a steady-state voltage value, and maintains the estimated direct-axis voltage Vδ is a high-frequency AC signal (the estimated direct-axis voltage Vδ is regarded as another voltage component of the estimated voltage command). The coordinate converter 111 performs coordinate transformation on the estimated direct-axis voltage Vδ and the steady-state voltage value to generate the first voltage component Vα and the second voltage component Vβ of the two-axis voltage command. Next, the control arithmetic unit 110 provides the first voltage component Vα and the second voltage component Vβ to the driving arithmetic unit 120 . In this embodiment, the estimated direct-axis voltage Vδ and the estimated quadrature-axis voltage Vγ represent the estimated coordinate axis, and the first voltage component Vα and the second voltage component Vβ represent the stationary coordinate axis, but the present disclosure is not limited thereto.

Next, the calculation of the direct-axis inductance Ld is used as an example of coordinate transformation. As shown in FIGS. 2 and 3A, in order to accurately calculate the direct-axis inductance Ld, the control operation unit 110 receives the estimated direct-axis voltage Vδ and the estimated quadrature-axis voltage Vγ of the estimated voltage command, and controls the operation unit 110 Adjust the estimated quadrature axis voltage Vγ to zero (ie, the steady-state voltage value in step S301 ), as shown in equation (3):

(3)

(3)

為控制運算單元110接收的高頻交流訊號，視為估測直軸電壓Vδ。接著，依據方程式(3)進行座標轉換，即可取得二軸電壓命令的第一電壓分量Vα及第二電壓分量Vβ，如方程式(4)所示： In equation (3),

The high-frequency AC signal received by the control operation unit 110 is regarded as the estimated direct-axis voltage Vδ. Then, coordinate transformation is performed according to equation (3) to obtain the first voltage component Vα and the second voltage component Vβ of the two-axis voltage command, as shown in equation (4):

(4)

(4)

In equation (4), θv is the estimated value of the rotational position. It should be noted that, when the program is executed for the first time, the estimated value Θv of the rotational position is not obtained through feedback, but is preset in the program setting value of the coordinate converter 111 or is an external position command. Therefore, the coordinate converter 111 performs coordinate conversion according to the estimated direct-axis voltage Vδ and the steady-state voltage value of the estimated voltage command to obtain the first voltage component Vα and the second voltage component Vβ of the two-axis voltage command.

Similarly, in other preferred embodiments of step S302, in order to accurately calculate the quadrature-axis inductance Lq, the control operation unit 110 receives the estimated direct-axis voltage Vδ and the estimated quadrature-axis voltage Vγ of the estimated voltage command, and The control arithmetic unit 110 adjusts the estimated and estimated direct-axis voltage Vδ to be zero (ie, the steady-state voltage value in step S301 ). Next, the coordinate converter 111 performs coordinate conversion according to the estimated quadrature voltage Vγ and the steady-state voltage value of the estimated voltage command to obtain the first voltage component Vα and the second voltage component Vβ of the biaxial voltage command. Since the principle of the equations of this embodiment can be obtained by modifying equations (3) and (4), the present disclosure will not describe them in detail.

In step S303, after the driving operation unit 120 receives the first voltage component Vα and the second voltage component Vβ outputted by the coordinate converter 111, the driving operation unit 120 according to the DC excitation voltage command Vdc and the biaxial voltage command (including the first voltage component Vα or the second voltage component Vβ), three-phase excitation currents Ia, Ib, Ic are generated to drive the synchronous motor 200 to rotate to a rotating position and stop. It should be noted that, regarding the rotational position of the synchronous motor 200 (ie, the actual position Θa of the rotor 210 ), since this embodiment does not use a position sensor, the motor control device 200 cannot directly obtain the actual value of the rotational position.

Please refer to FIG. 2 , FIG. 3A and FIG. 3B at the same time to describe the operation of step S303 in detail. The step S303 includes steps S3031 to S3034. In step S3031, the driving operation unit 120 selects one of the first voltage component Vα and the second voltage component Vβ as the first driving command. In step S3032, the other one of the first voltage component Vα and the second voltage component Vβ is selected as the second driving command. For example: if the first voltage component Vα is selected as the first drive command, the second voltage component Vβ is selected as the second drive command. Likewise, if the second voltage component Vβ is selected as the first drive command, the first voltage component Vα is selected as the second drive command.

In step S3033, the driving operation unit 120 superimposes the DC excitation voltage command Vdc and the first driving command to generate the excitation driving voltage Vt. In step S3034, the driving arithmetic unit 120 generates three-phase excitation currents Ia, Ib, and Ic according to the excitation driving voltage Vt and the second driving command.

For example, if the first voltage component Vα is selected as the first driving command, the driving operation unit 120 superimposes the DC excitation voltage command Vdc and the first voltage component Vα. Next, the second voltage component Vβ is selected as the second drive command. Therefore, the driving operation unit 120 arranges the equation (4) and the DC excitation voltage command Vdc to obtain the equation (5), as shown below:

(5)

(5)

In equation (5), Vt is the excitation drive voltage. After the driving operation unit arranges equations (3), (4) and (5), equation (6) can be obtained, as shown below:

(6)

(6)

Referring to equation (6), the driving operation unit 120 generates three-phase excitation currents Ia, Ib, and Ic according to the excitation driving voltage Vt and the second voltage component Vβ (ie, the second driving command).

Similarly, in steps S3033 and S3034, if the second voltage component Vβ is selected as the first driving command, the driving operation unit 120 superimposes the DC excitation voltage command Vdc and the second voltage component Vβ. Next, in step S3034, the driving arithmetic unit 120 generates three-phase excitation currents Ia, Ib, and Ic according to the excitation driving voltage Vt and the first voltage component Vα (ie, the second driving command). In this embodiment, those skilled in the art can modify equations (5) and (6) to obtain the excitation driving voltage Vt and generate three-phase excitation currents Ia, Ib, and Ic. Therefore, the content of the present disclosure will not be repeated.

It should be noted that FIG. 2 of the present disclosure is only used to describe an example in which the first voltage component Vα is selected as the first driving command, and the driving operation unit 120 superimposes the DC excitation voltage command Vdc and the first voltage component Vα. To simplify the description of the present disclosure, an example in which the second voltage component Vβ is selected as the first driving command and the driving operation unit 120 superimposes the DC excitation voltage command Vdc and the second voltage component Vβ is not repeated.

In step S303 , the driving arithmetic unit 120 generates three-phase excitation currents Ia, Ib, and Ic to drive the synchronous motor 200 to rotate to a rotating position and stop. As shown in FIG. 2 , the driving operation unit 120 includes a two-phase to three-phase converter 121 and a PWM modulation circuit 122 . The two-phase-to-three-phase converter 121 generates three-phase voltages Va, Vb, Vc after receiving the excitation driving voltage Vt and the second voltage component Vβ (ie, the second driving command). The PWM modulation circuit 122 switches the three-phase voltages Va, Vb, and Vc to generate three-phase currents Ia, Ib, and Ic. Alternatively, in other embodiments, after the two-phase-to-three-phase converter 121 receives the excitation driving voltage Vt and the first voltage component Vα (ie, the second driving command), the two-phase-to-three-phase converter 121 generates the three-phase voltage Va , Vb, Vc. The PWM modulation circuit 122 switches the three-phase voltages Va, Vb, and Vc to generate three-phase currents Ia, Ib, and Ic.

In some embodiments, the purpose of receiving the DC excitation voltage command Vdc by the driving operation unit 120 is to make the output torque of the synchronous motor 200 zero, so that the synchronous motor 200 stops at the set rotational position. In general, the torque equation for a synchronous motor is shown in equation (7):

(7)

(7)

為同步馬達輸出的轉矩，P為同步馬達的極數，

為同步座標軸的交軸電流，

為同步座標軸的直軸電流，Ld代表直軸電感量，Lq代表交軸電感量，

為轉子磁通等效至定子磁通。 In equation (7),

is the output torque of the synchronous motor, P is the number of poles of the synchronous motor,

is the quadrature current of the synchronous coordinate axis,

is the direct-axis current of the synchronous coordinate axis, Ld represents the direct-axis inductance, Lq represents the quadrature-axis inductance,

Equivalent to the rotor flux to the stator flux.

Converting equation (7) into stationary coordinate axes (α-axis and β-axis), and assuming that the estimated value θv is zero degrees, equation (8) can be obtained as follows:

(8)

(8)

From equation (8), the control device of a general synchronous motor can control the rotor of the synchronous motor to rotate to a rotating position and stop according to the DC excitation voltage. Therefore, in the present disclosure, the synchronous motor 200 (reluctance motor) can also use the same aforementioned principle to make the rotor of the synchronous motor 200 rotate to a rotating position and then stop. In addition, as can be seen from equation (8), based on the structural characteristics of the reluctance motor, the direct-axis inductance Ld of the reluctance motor is different from the quadrature-axis inductance Lq. Therefore, the output torque in Equation (8) includes the electromagnetic torque generated by the magnet component and the reluctance torque generated by the inductance difference (Ld, Lq). When performing DC excitation (step S303 ), due to the synthesis of two different torques, when the torque is zero, the difference between the estimated coordinate axis (δ axis, γ axis) and the actual synchronous coordinate axis (d axis and q axis) The angle between them will not be zero.

In step S304, the feedback operation unit 130 captures the three-phase excitation currents Ia, Ib, and Ic, and establishes an estimated coordinate axis according to the three-phase excitation currents Ia, Ib, and Ic, so as to calculate the estimated current signal (including: estimated direct current signal). shaft current Iδ and estimated quadrature-axis current Iγ), wherein a current component of the estimated current signal corresponds to a steady-state voltage value. Note that since the estimated voltage command and the estimated current signal correspond to the same estimated coordinate axis and the motor has been stopped (step S303 ), the estimated direct-axis current Iδ corresponds to the estimated direct-axis voltage Vδ, and the estimated quadrature axis The current Iγ corresponds to the estimated quadrature axis voltage Vγ. If the angle error Θer (Fig. 1B) is small, the estimated coordinate axes (δ axis, γ) and the synchronous coordinate axis (d axis, q axis) can be regarded as aligned. When the estimated coordinate axis is aligned with the synchronous coordinate axis, the estimated quadrature axis current Iγ corresponding to the steady-state voltage value (ie: when the estimated quadrature axis voltage Vγ is adjusted to the steady-state voltage value) is not observed close to the estimated direct current value. The frequency of the high frequency AC signal of the shaft voltage Vδ. Therefore, the estimated quadrature-axis current Iγ is maintained at the steady-state current value. Conversely, if the angle error Θer (Fig. 1B) is large, the estimated coordinate axes (δ axis, γ) and the synchronous coordinate axes (d axis, q axis) are not aligned. When the estimated coordinate axis is not aligned with the synchronous coordinate axis, the estimated quadrature axis current Iγ corresponding to the steady-state voltage value (ie: when the estimated quadrature axis voltage Vγ is adjusted to the steady-state voltage value) is observed to obtain a similar estimated quadrature axis. The frequency of the high frequency AC signal of the voltage Vδ.

It should be noted that, if the motor is not stopped, there will be a coupling between the estimated voltage command and the estimated current signal, so that the estimated direct-axis current Iδ cannot accurately estimate the direct-axis voltage Vδ, and the estimated AC The axis current Iγ cannot accurately estimate the quadrature axis voltage Vγ accordingly. Therefore, if the control arithmetic unit 110 adjusts the estimated quadrature-axis voltage Vγ to be the steady-state voltage value (step S301 ), the estimated quadrature-axis current Iγ corresponds to the steady-state voltage value. On the other hand, if the control arithmetic unit 110 adjusts the estimated direct-axis voltage Vδ to be the steady-state voltage value (step S301 ), the estimated direct-axis current Iδ corresponds to the steady-state voltage value.

As shown in FIG. 2 , the feedback operation unit 130 includes a current sensing processing unit 131 , a three-phase to two-phase converter 132 and a position estimator 133 . The current sensing processing unit 131 captures the AC components of the three-phase excitation currents Ia, Ib, and Ic, and outputs the feedback AC signal components Ia_ac to Ic_ac to the three-phase-to-two-phase converter 132 .

The three-phase to two-phase converter 132 establishes an estimated coordinate axis according to the feedback AC signal components Ia_ac~Ic_ac, so as to calculate the estimated current signals (Iδ, Iγ). Since the operation principle of the three-phase-to-two-phase converter 132 is well known to those skilled in the art, the content of this disclosure will not be repeated. In some embodiments, the current sensing processing unit 131 includes a plurality of current sensors (not shown), and each of the plurality of current sensors is used to capture the feedback AC signal components Ia_ac˜Ic_ac respectively.

In step S305, the position estimator 133 determines whether the current component corresponding to the steady-state voltage value is maintained at the steady-state current value. Theoretically, if the control arithmetic unit 110 adjusts the estimated quadrature-axis voltage Vγ to a steady-state voltage value (step S301 ), the estimated quadrature-axis current Iγ should be maintained at the steady-state current value. On the other hand, if the control arithmetic unit 110 adjusts the estimated direct-axis voltage Vδ to be the steady-state voltage value (step S301 ), the estimated direct-axis current Iδ should be maintained at the steady-state current value.

However, as shown in Fig. 1A, due to the angular error between the synchronous coordinate axis (used to represent the actual position of the rotor) and the estimated coordinate axis (ie: the actual position of the rotor Θa), the current component corresponding to the steady-state voltage value is caused Contains high-frequency AC signals, and cannot maintain a steady-state current value. For example, if the control arithmetic unit 110 adjusts the estimated quadrature-axis voltage Vγ to be a steady-state voltage value, the estimated quadrature-axis current Iγ includes a high-frequency AC signal. Similarly, if the control operation unit 110 adjusts the estimated direct-axis voltage Vδ to be a steady-state voltage value, the estimated direct-axis current Iδ includes a high-frequency AC signal. If the position estimator 133 determines that the current component (the estimated direct-axis current Iδ or the estimated quadrature-axis current Iγ) corresponding to the steady-state voltage value is not maintained at the steady-state current value, the motor control apparatus 100 proceeds to step S306 .

In step S306 , the position estimator 133 calculates the estimated value Θv of the rotational position of the synchronous motor 200 to the control arithmetic unit 110 and the three-phase to two-phase converter 132 according to the estimated current signals (Iδ and Iγ). The three-phase to two-phase converter 132 adjusts the estimated direct-axis current Iδ and the estimated quad-axis current Iγ of the estimated current signal according to the estimated value Θv, so as to improve the accuracy of the estimated value Θv.

As mentioned above, the position estimator 133 calculates the estimated value Θv of the rotational position of the synchronous motor 200 according to the estimated direct-axis current Iδ or the estimated quadrature-axis current Iγ. The calculation method is the reference: Chen, J., Tseng, S., & Liu, T. (2012). Implementation of high-performance sensorless interior permanent-magnet synchronous motor control systems using a high-frequency injection technique. IET Electric Power Applications, 6(8), 533. doi:10.1049/iet-epa.2011.0303. Therefore, the present disclosure will not repeat its calculation method, but the present disclosure is not limited thereto.

In step S307, the control arithmetic unit 110 adjusts another voltage component of the estimated voltage command according to the estimated value Θv of the rotational position, so that the current component of the corresponding steady-state voltage value is maintained at the steady-state current value. For example, when the control arithmetic unit 110 adjusts the estimated direct-axis voltage Vδ to be a steady-state voltage value, the control and arithmetic unit 110 adjusts the estimated quadrature-axis voltage Vγ according to the estimated value Θv of the rotational position, so that the estimated value of the corresponding steady-state voltage value is estimated. The measured direct axis current Iδ is maintained at the steady state current value.

Or, in other embodiments, when the control arithmetic unit 110 adjusts the estimated quadrature axis voltage Vγ to be a steady-state voltage value, the control arithmetic unit 110 adjusts the estimated quadrature axis voltage Vδ according to the estimated value Θv of the rotational position, such that The estimated quadrature axis current Iγ corresponding to the steady-state voltage value is maintained at the steady-state current value. When the motor control device 100 completes step S307, the motor control device 100 returns to step S305: the position estimator 133 determines whether the current component corresponding to the steady-state voltage value is maintained at the steady-state current value.

When the position estimator 133 determines that the current component corresponding to the steady-state voltage value maintains the steady-state current value, the motor control device 100 proceeds to step S308 .

In step S308, the control arithmetic unit 110 calculates the effective inductance (direct current) of the synchronous motor according to the steady-state voltage value, another voltage component of the estimated voltage command, the steady-state current value, and another current component of the estimated current signal. Axial inductance Ld or quadrature inductance Lq). Please refer to Table 1 below to illustrate the calculation method for adjusting each parameter: steady state voltage another voltage component Steady state current value another current component Effective inductance Estimated quadrature axis voltage Vγ Estimated direct axis voltage Vδ Estimated quadrature axis current Iγ Estimated direct axis current Iδ Direct axis inductance Ld Estimated direct axis voltage Vδ Estimated quadrature axis voltage Vγ Estimated direct axis current Iδ Estimated quadrature axis current Iγ Quadrature axis inductance Lq Table 1

As can be seen from Table 1 above, if the control arithmetic unit 110 selects the estimated quadrature-axis voltage Vγ as the voltage component adjusted to the steady-state voltage value (ie: when the estimated quadrature-axis voltage Vγ is adjusted to the steady-state voltage value), then : The other voltage component of the estimated voltage command is to estimate the direct-axis voltage Vδ; the current component corresponding to the steady-state voltage value is to estimate the quadrature-axis current Iγ; the other current component of the estimated current signal is to estimate the direct-axis current Iδ; and the calculated effective inductance is the direct-axis inductance Ld.

If the control arithmetic unit 110 selects the estimated direct-axis voltage Vδ as the voltage component adjusted to the steady-state voltage value (ie: when the estimated direct-axis voltage Vδ is adjusted to the steady-state voltage value), then: The other voltage component is the estimated quadrature axis voltage Vγ; the current component corresponding to the steady state voltage value is the estimated quadrature axis current Iδ; the other current component of the estimated current signal is the estimated quadrature axis current Iγ; and the calculated The effective inductance is the quadrature inductance Lq.

In a preferred embodiment, the steady-state voltage value is zero, but the present disclosure is not limited thereto. It should be noted that, in step S303, the drive arithmetic unit adds the DC excitation command Vdc to the stationary coordinate axes (Vα, Vβ). Due to the factor of the DC excitation command Vdc, when the estimated quadrature axis voltage Vγ is adjusted to zero, the estimated quadrature axis current Iγ is maintained at a non-zero steady-state current value. Likewise, due to the DC excitation command Vdc, when the estimated direct-axis voltage Vδ is adjusted to zero, the estimated direct-axis current Iδ is maintained at a non-zero steady-state current value.

FIG. 4 is a schematic diagram of a motor control apparatus according to some embodiments of the present disclosure. 5A is a flowchart of a motor control method according to some embodiments of the present disclosure. 5B is a flowchart of a method of generating a three-phase excitation current according to some embodiments of the present disclosure. Please refer to FIG. 4 , FIG. 5A and FIG. 5B at the same time to describe the following embodiments.

The present disclosure provides a motor control method 500 , and the motor control method 500 is suitable for a synchronous motor 200 having a position sensor 140 (eg, an encoder), and the position sensor 140 is coupled to the synchronous motor 200 . The motor control method 500 is executed by the motor control device 100, and the motor control method 500 includes steps S501-S508.

The operation methods of steps S501 to S505 are the same as those of steps S301 to S305. Therefore, the content of this disclosure will not be repeated here.

In step S506 , the position sensor 140 measures the rotational position of the rotor 210 of the synchronous motor 200 and outputs the measured value Θm to the position estimator 133 of the feedback operation unit 130 . Therefore, the position estimator 133 of the feedback operation unit 130 obtains the measured value Θm of the rotational position through the position sensor 140 . Next, the position estimator 133 outputs the measured value Θm of the rotational position to the control arithmetic unit 110 . In addition, when the motor control device 100 executes step S506, the feedback computing unit 130 still captures the feedback AC signal components Ia_ac~Ic_ac of the three-phase excitation currents Ia~Ic of the synchronous motor 200 to calculate the estimated current signal ( Iδ, Iγ) (same as step S304, so it is not repeated here).

It is particularly noted that, according to different situations, the position sensor 140 may be disposed inside or outside the motor control device 100 , but the present disclosure is not limited thereto.

In step S507, the control arithmetic unit 110 adjusts another voltage component of the estimated voltage command according to the measured value Θm of the rotational position, so that the current component of the corresponding steady-state voltage value is maintained at the steady-state current value (the method is similar to that of step S307). ). The operation methods of steps S507 to S508 are the same as those of steps S307 and S308. Therefore, the content of this disclosure will not be repeated here.

Therefore, in the synchronous motor 200 having the position sensor 140, the motor control device 100 can also follow the steps shown in FIG. 3, when the current component corresponding to the steady-state voltage value is maintained at the steady-state current value, according to The voltage Vδ, the quadrature axis voltage Vγ, the direct axis current signal Iδ and the quadrature axis current signal Iγ are used to calculate the direct axis inductance or quadrature axis inductance of the synchronous motor 200 . The motor control device 100 measures the rotational position of the synchronous motor 200 through the position sensor 140 instead of evaluating the rotational position of the synchronous motor 200 by estimating the current signals (Iδ, Iγ). Therefore, in this embodiment, the motor control device 100 can omit the complicated calculation, and can more effectively reduce the influence caused by the actual position Θa of the rotor.

To sum up, the key point of the present disclosure is to calculate the excitation angle value according to the estimated voltage command, and to control the rotor of the synchronous motor 200 to rotate to the rotating position and then stop. Next, by detecting or calculating the rotor position of the synchronous motor 200, the position error between the rotor position and the excitation angle value is reduced. In this way, the present disclosure can more accurately calculate the direct-axis inductance or the quadrature-axis inductance of the synchronous motor 200 .

The various elements, method steps or technical features in the foregoing embodiments can be combined with each other, and are not limited by the order of text description or the order of presentation of the drawings in the content of the present disclosure.

Although the content of the present invention has been disclosed in the above embodiments, it is not intended to limit the content of the present invention. Anyone skilled in the art can make various changes and modifications without departing from the spirit and scope of the content of the present invention. Therefore, the present invention The scope of protection of the content shall be determined by the scope of the appended patent application.

100: Motor control device 110: Control arithmetic unit 111: Coordinate Converter 112: Inductance operation unit 120: Drive arithmetic unit 121: Two-phase to three-phase converter 122: PWM modulation circuit 130: Feedback operation unit 131: Current Sensing Processing Unit 132: Three-phase to two-phase converter 133: Position Estimator 140: Position Sensor 200: Synchronous motor 210: Rotor 220: Stator Vδ: estimated direct axis voltage Vγ: Estimated quadrature axis voltage Vdc: DC excitation voltage Command: Vα: first voltage component Vβ: the second voltage component Vt: excitation drive voltage Va-Vc: Three-phase driving voltage Ia～Ic: Three-phase excitation current Ia_ac: Feedback AC signal component Ib_ac: Feedback AC signal component Ic_ac: Feedback AC signal component Iδ: estimated direct axis current Iγ: estimated quadrature axis current Θv: estimated value Θm: measured value Θer: angle error Ld: direct axis inductance Lq: quadrature axis inductance 300, 500: Motor control method S301-S308: Steps S3031-S3034: Steps S501-S508: Steps S5031-S5034: Steps

FIG. 1A is a schematic diagram of coordinate axis transformation according to a conventional technique. FIG. 1B is a schematic diagram of coordinate conversion according to some embodiments of the present disclosure. FIG. 2 is a schematic diagram of a motor control apparatus according to some embodiments of the present disclosure. 3A is a flowchart of a motor control method according to some embodiments of the present disclosure. 3B is a flowchart of a method of generating a three-phase excitation current according to some embodiments of the present disclosure. FIG. 4 is a schematic diagram of a motor control apparatus according to some embodiments of the present disclosure. 5A is a flowchart of a motor control method according to some embodiments of the present disclosure. 5B is a flowchart of a method of generating a three-phase excitation current according to some embodiments of the present disclosure.

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300: Motor Control Method

S301-S308: Steps

Claims (14)

A motor control method for a synchronous motor without a position sensor, wherein the motor control method comprises: adjusting a voltage component of an estimated voltage command to a steady-state voltage value; performing coordinate axis transformation on another voltage component of the estimated voltage command and the steady-state voltage value to generate a two-axis voltage command; According to the DC excitation voltage command and the two-axis voltage command, a three-phase excitation current is generated to drive the synchronous motor to rotate to a rotation position and stop; extracting the three-phase excitation current to calculate an estimated current signal, wherein a current component of the estimated current signal corresponds to the steady-state voltage value; when it is determined that the current component is not maintained at a steady-state current value, calculating an estimated value of the rotational position according to the estimated current signal; adjusting the other voltage component of the estimated voltage command according to the estimated value of the rotational position so that the current component corresponding to the steady-state voltage value is maintained at the steady-state current value; and When it is determined that the current component maintains the steady-state current value, according to the steady-state voltage value, the other voltage component of the estimated voltage command, the steady-state current value and the other current component of the estimated current signal, calculate an effective inductance of the synchronous motor. The motor control method of claim 1, wherein the two-axis voltage command includes a first voltage component and a second voltage component, and the motor control method further comprises: selecting the first voltage component and the second voltage component One of them as a first drive command; selecting the other one of the first voltage component and the second voltage component as a second driving command; superimposing the DC excitation voltage command and the first driving command to generate an excitation driving voltage; and The three-phase excitation current is generated according to the excitation driving voltage and the second driving command. The motor control method of claim 1, wherein the estimated voltage command includes an estimated direct-axis voltage and an estimated quad-axis voltage, and the estimated current signal includes an estimated direct-axis current and an estimated quad-axis voltage shaft current. The motor control method as claimed in claim 3, further comprising: The estimated direct-axis current and the estimated quadrature-axis current of the estimated current signal are adjusted according to the estimated value of the rotational position. The motor control method of claim 3, wherein the estimated quadrature axis voltage of the estimated voltage command is adjusted to the steady-state voltage value, and the other voltage component of the estimated voltage command is the estimated direct axis voltage; the current component corresponding to the steady state voltage value is the estimated quadrature current; the other current component of the estimated current signal is the estimated direct axis current; and the effective inductance is the direct axis inductance . The motor control method of claim 3, wherein the estimated direct-axis voltage of the estimated voltage command is adjusted to the steady-state voltage value, The other voltage component of the estimated voltage command is the estimated quadrature axis voltage; the current component corresponding to the steady state voltage value is the estimated direct axis current; the other current component of the estimated current signal is the estimated quadrature current; and the effective inductance is a quadrature inductance. The motor control method of claim 1, wherein the steady state voltage value is zero. A motor control method for a synchronous motor, wherein a position sensor is coupled to the synchronous motor, and the motor control method includes: adjusting a voltage component of an estimated voltage command to a steady-state voltage value; performing coordinate axis transformation on another voltage component of the estimated voltage command and the steady-state voltage value to generate a two-axis voltage command; According to the DC excitation voltage command and the two-axis voltage command, a three-phase excitation current is generated to drive the synchronous motor to rotate to a rotation position and stop; extracting the three-phase excitation current to calculate an estimated current signal, wherein a current component of the estimated current signal corresponds to the steady-state voltage value; When it is determined that the current component is not maintained at a steady-state current value, a measurement value of the rotational position is obtained by the position sensor; adjusting the other voltage component of the estimated voltage command according to the measured value of the rotational position so that the current component corresponding to the steady-state voltage value is maintained at the steady-state current value; and When it is determined that the current component maintains the steady-state current value, according to the steady-state voltage value, the other voltage component of the estimated voltage command, the steady-state current value and the other current component of the estimated current signal, calculate an effective inductance of the synchronous motor. The motor control method of claim 8, wherein the two-axis voltage command includes a first voltage component and a second voltage component, and the motor control method further includes: selecting one of the first voltage component and the second voltage component as a first drive command; selecting the other one of the first voltage component and the second voltage component as a second driving command; superimposing the DC excitation voltage command and the first driving command to generate an excitation driving voltage; and The three-phase excitation current is generated according to the excitation driving voltage and the second driving command. The motor control method of claim 8, wherein the estimated voltage command includes an estimated direct-axis voltage and an estimated quadrature-axis voltage, and the estimated current signal includes an estimated direct-axis current and an estimated quadrature-axis voltage shaft current. The motor control method of claim 10, further comprising: adjusting the estimated direct-axis current and the estimated quadrature-axis current of the estimated current signal according to the measured value of the rotational position. The motor control method of claim 10, wherein the estimated quadrature axis voltage of the estimated voltage command is adjusted to the steady-state voltage value, and the other voltage component of the estimated voltage command is the estimated direct axis voltage; the current component corresponding to the steady state voltage value is the estimated quadrature current; the other current component of the estimated current signal is the estimated direct axis current; and the effective inductance is the direct axis inductance . The motor control method of claim 10, wherein the estimated direct-axis voltage of the estimated voltage command is adjusted to the voltage component of the steady-state voltage value, and the other voltage component of the estimated voltage command is the estimated quadrature axis voltage; the current component corresponding to the steady-state voltage value is the estimated quadrature axis current; the other current component of the estimated current signal is the estimated quadrature axis current; and the effective inductance is A quadrature inductance. The motor control method of claim 8, wherein the steady state voltage value is zero.

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