TWI753767B - Motor demagnetization detection method and motor demagnetization detection device - Google Patents

Abstract

A motor demagnetization detection device includes the following steps. An encoder is used to measure a rotation angle of a motor device. A current sensing device is used to measure a three-phase current value of the motor device. A speed of the motor device is calculated according to the rotation angle. When determining that the motor device maintains at a first steady state according to the speed, the three-phase current value is received to obtain and store first steady state data. When determining that the motor device maintains at a second steady state according to the speed, the three-phase current value is received to obtain and store second steady state data. An equivalent magnetic flux is calculated and stored according to the first steady state data and the second steady state data. The motor device is repeatedly driven to maintain at the first steady state and the second steady state, the first steady state data and the second steady state data are updated according to the three-phase current value, and the equivalent magnetic flux is again calculated and stored to generate a plurality of equivalent magnetic fluxes. A magnetic flux change is calculated according to the equivalent magnetic fluxes. A demagnetization warning is issued according to a comparison result of the magnetic flux change and a demagnetization warning value.

Description

Motor demagnetization detection method and motor demagnetization detection device

The present invention relates to a motor detection method and a motor detection device, and in particular to a motor demagnetization detection method and a motor demagnetization detection device for detecting a change in magnetic flux.

Generally speaking, the permanent magnet synchronous motor does not need additional excitation current to generate the rotor magnetic field, and has the advantages of high efficiency, low inertia and high power density. In recent years, permanent magnet synchronous motors have been widely used in industrial applications, such as: electric vehicles, robotic arms, elevators, etc.

On the other hand, it is common to add field weakening control to the control of the permanent magnet synchronous motor, that is, to appropriately add demagnetization current to the direct axis (or d-axis) of the permanent magnet synchronous motor to extend the speed operating range. However, excessive direct axis current can cause permanent demagnetization of the rotor magnets, thereby reducing motor performance. In addition, as the temperature of the rotor increases, the direct-axis current that permanently demagnetizes the magnet will also decrease, making the permanent magnet synchronous motor more prone to permanent demagnetization. Therefore, how to effectively detect the demagnetization phenomenon of the motor or the motor is an important issue at present.

The present invention provides a motor demagnetization detection method and a motor demagnetization detection device, so as to effectively estimate the magnetic flux and reduce the magnetic flux estimation error, so as to increase the detection accuracy of the demagnetization phenomenon.

The present invention provides a motor demagnetization detection method for detecting a motor device, and the motor demagnetization detection method includes the following steps. The rotation angle of the motor device is measured by the encoder. The three-phase current value of the motor device is measured by the current sensing device. The rotational speed of the motor unit is calculated based on the rotation angle. When it is determined according to the rotational speed that the motor device is maintained in the first steady state, the three-phase current value is received to obtain and store the first steady state data. When it is determined according to the rotational speed that the motor device is maintained in the second steady state, the three-phase current value is received to obtain and store the second steady state data. The equivalent magnetic flux is calculated and stored according to the first steady state data and the second steady state data. Repeatedly driving the motor device to maintain the first steady state and the second steady state, updating the first steady state data and the second steady state data according to the three-phase current value, and recalculating and storing the equivalent magnetic flux to generate a plurality of etc. effective magnetic flux. Calculates the change in magnetic flux based on the equivalent magnetic flux. A demagnetization warning is issued based on the comparison result of the magnetic flux change and the demagnetization warning value.

The present invention provides a motor demagnetization detection device for detecting a motor device. The motor demagnetization detection device includes an encoder, a current sensing device and a controller. The encoder is used to measure the rotation angle of the motor device. The current sensing device is used to measure the three-phase current value of the motor device. The controller is coupled to the encoder and the current sensing device. The controller calculates the rotational speed of the motor device according to the rotation angle. When the controller determines that the motor device is maintained in the first steady state according to the rotational speed, the controller receives the three-phase current values to obtain and store the first steady state data. When the controller determines that the motor device is maintained in the second steady state according to the rotational speed, the controller receives the three-phase current values to obtain and store the second steady state data. The controller calculates and stores the equivalent magnetic flux according to the first steady state data and the second steady state data. The motor device is repeatedly driven to maintain the first steady state and the second steady state, the controller updates the first steady state data and the second steady state data according to the three-phase current value, and recalculates and stores the equivalent magnetic flux to generate a plurality of Equivalent Magnetic Flux. The controller calculates the magnetic flux change amount according to the equivalent magnetic flux, and the controller issues a demagnetization warning according to the comparison result of the magnetic flux change amount and the demagnetization warning value.

The motor demagnetization detection method and the motor demagnetization detection device disclosed in the present invention obtain and store the first steady state data by receiving three-phase current values when it is determined according to the rotational speed of the motor device that the motor device is maintained in the first steady state. The rotational speed of the motor device determines that when the motor device is maintained in the second steady state, the three-phase current values are received to obtain and store the second steady state data, and the equivalent magnetic flux is calculated and stored according to the first steady state data and the second steady state data, And repeatedly drive the motor device to maintain the first steady state and the second steady state, update the first steady state data and the second steady state data according to the three-phase current value, and recalculate and store the equivalent magnetic flux to generate a plurality of The equivalent magnetic flux is calculated, and the magnetic flux change is calculated according to the equivalent magnetic flux, and the demagnetization warning is issued according to the comparison result of the magnetic flux change and the demagnetization warning value. In this way, the magnetic flux can be effectively estimated and the magnetic flux estimation error caused by the nonlinear characteristics of the integrated circuit can be reduced, so as to increase the accuracy of detecting the demagnetization phenomenon, and the motor parameters related to the motor (such as direct current) can be omitted. shaft inductance) to increase the convenience and accuracy of detection.

In the various embodiments listed below, the same or similar elements or components will be represented by the same reference numerals.

FIG. 1 is a schematic diagram of a motor demagnetization detection device according to an embodiment of the present invention. The motor demagnetization detection device 100 of this embodiment is used to detect the motor device 150 , wherein the motor device 150 may include an inverter 151 and a motor 152 . The inverter 151 can output the three-phase current values _ia , _ib , _ic according to the control commands, so as to drive the motor 152 and make the motor 152 run. In this embodiment, the motor demagnetization detection device 100 may first receive a speed command, and generate a control command to the inverter 151 according to the speed command. In some embodiments, the motor 152 is, for example, a permanent magnet synchronous motor, and the motor 152 may be applied to elevators, electric vehicles, robotic arms, etc., but the embodiments of the present invention are not limited thereto. Further, the motor device 150 may also include a rectifier 153 . The rectifier 153 is coupled to the inverter 151 and provides a rectified voltage to the inverter 151 . In addition, the rectifier 153 is, for example, a full bridge rectifier, but the embodiment of the present invention is not limited thereto.

Please refer to FIG. 1 , the motor demagnetization detection device 100 may include an encoder 110 , a current sensing device 120 and a controller 130 .

The encoder 110 measures the rotation angle of the motor device 150 (eg, the motor 151 ) to output a motor position signal. In this embodiment, the encoder 110 may be a position sensor.

、

、

)。 The current sensing device 120 is used to measure the three-phase current value of the motor device 150 . Further, the current sensing device 120 is coupled to the output end of the inverter 151, and measures the three-phase current values _ia , _ib , ic output by the inverter 151 to generate the three-phase current values _ia , _{i b} , the current detection value of _ic (for example

,

,

).

、

)並且控制器130可以依據第一相電流(例如 i _a ) 對應的電流偵測值(例如

)及第二相電流(例如 i _b )對應的電流偵測值(例如

)計算出三相電流值之第三相電流(例如 i _c )對應的電流偵測值(例如

)。 In some embodiments, the current sensing device 120 may include two current sensors 210 , 220 , as shown in FIG. 2 . The current sensors 210 and 220 are respectively used to measure the first phase current (eg i _a ) and the second phase current (eg _{ib )} of the three-phase current values i _a , _ib , ic output by the inverter 151 , to generate the corresponding current detection value (eg

,

) and the controller 130 can detect the current value (eg, _ia ) corresponding to the first phase current

) and the current detection value corresponding to the second phase current (eg i _b ) (eg

) to calculate the current detection value corresponding to the third-phase current (eg _ic ) of the three-phase current value (eg

).

、

、

)。特別注意的是，電流感測器210、220、310、320、330可以是霍爾感測器(Hall sensor)或電流感測電阻(current sensing resistor)，但本發明不限於此。 In some embodiments, the current sensing device 120 may include three current sensors 310 , 320 , 330 . The current sensors 310 , 320 and 330 respectively measure the first phase current (eg _ia ) and the second phase current (eg _ib ) of the three-phase current values _ia , _ib , _ic output by the inverter 151 and the third phase current (eg _ic ), so that the current sensing device 120 can generate current detection values of the three-phase current values _ia , _ib , _ic (eg

,

,

). It is particularly noted that the current sensors 210 , 220 , 310 , 320 and 330 may be Hall sensors or current sensing resistors, but the present invention is not limited thereto.

The controller 130 is coupled to the inverter 151 , the encoder 110 and the current sensing device 120 . The controller 130 may provide control commands to the frequency converter 151 . The controller 130 can receive the motor position signal output by the encoder 110 and the current detection value generated by the current sensing device 120, and the controller 130 can calculate the motor 152 (the motor device 150) according to the motor position signal (eg rotation angle) speed. Usually, the controller 130 determines the rotation angle of the motor 152 according to the motor position signal, and differentiates the rotation angle of the motor 152 to obtain the rotation speed of the motor 152 .

Next, the controller 130 can determine whether the motor device 150 is maintained at the first steady state according to the obtained rotation speed of the motor 152 (eg, determine whether the rotation speed of the motor 152 is maintained at the first rated rotation speed for more than a first predetermined time and within a first error range). In this embodiment, the first rated rotational speed is, for example, 1000 rpm, and the first error range is, for example, 5%. That is, the controller 130 determines whether the rotational speed of the motor 152 is maintained within 5% of the first rated rotational speed, for example, between 950 rpm and 1050 rpm. However, the first rated rotational speed is 1000 rpm, and the first error range is 5% is only an embodiment of the present invention, and is not used to limit the embodiment of the present invention. In other embodiments, the user can also set the first rated speed to 800rpm, 900rpm, 1100rpm, 1200rpm, etc. according to his needs, and the first error range is 2%, 8%, 10%, 15%, etc.

When the controller 130 determines that the motor device 150 is not maintained at the first steady state (for example, the rotational speed of the motor 152 is not maintained at the first rated rotational speed for more than the first predetermined time and within the first error range), the controller 130 will continue to follow the encoder The motor position signal output by 110 calculates the rotational speed of the motor 152 to determine again whether the motor device 150 is maintained in the first steady state.

、

、

)以取得並儲存第一穩態資料。在本實施例中，第一穩態資料可以包括第一直軸電流(例如 i _{d 1})、第一直軸電壓(例如 v _{d 1})、第一交軸電流(例如 i _{q 1})及第一交軸電壓(例如 v _{q 1})。 When the controller 130 determines that the motor device 150 is maintained in the first steady state (eg, the rotation speed of the motor 152 is maintained at the first rated rotation speed for more than a first predetermined time and within a first error range), the controller 130 receives the three-phase current value Current detection values corresponding to _{i a} , _ib , and ic (for example,

,

,

) to obtain and store the first steady state data. In this embodiment, the first steady-state data may include a first linear current (eg, i _{d 1} ), a first linear voltage (eg, v _{d 1} ), a first quadrature current (eg, i _{q 1} ), and a first linear voltage (eg, v d 1 ). A quadrature axis voltage (eg v _{q 1} ).

Then, the controller 130 can determine whether the motor device 150 is maintained at the second steady state according to the obtained rotation speed of the motor 152 (eg, determine whether the rotation speed of the motor 152 is maintained at the second rated rotation speed for more than a second preset time and at the second within the error range). In this embodiment, the second rated rotational speed is, for example, 50 rpm, and the second error range is, for example, 10%. That is, the controller 130 determines whether the rotational speed of the motor 152 is maintained within 10% of the second rated rotational speed, for example, the rotational speed is maintained between 45 rpm and 55 rpm. However, the second predetermined rated rotational speed is 50 rpm, and the second error range is 10% is only an embodiment of the present invention, and is not used to limit the embodiment of the present invention. In other embodiments, the user can also set the second predetermined rated rotational speed to 30 rpm, 40 rpm, 60 rpm, 80 rpm, etc. according to his needs, and the second error range is 5%, 8%, 15%, etc.

In one embodiment, the first rated rotational speed, the second rated rotational speed, the first error range and the second error range are programmed values in the controller 130 . Usually, the second rated rotational speed is lower than the first rated rotational speed, but the present invention is not limited thereto. In some other embodiments, the second rated speed is generally zero, eg, a motor of an elevator system. When the elevator car reaches the designated floor, the speed of the motor of the elevator system is zero.

When the controller 130 determines that the motor device 150 is not maintained in the second steady state (for example, the rotational speed of the motor 152 is not maintained at the second rated rotational speed beyond the second preset time and within the second error range), the controller 130 will continue to The motor position signal output by the encoder 110 obtains the rotational speed of the motor 152 to determine again whether the motor device 150 is maintained in the second steady state.

、

、

)以取得並儲存第二穩態資料。在本實施例中，第二穩態資料可以包括第二直軸電流(例如 i _{d 2})、第二直軸電壓(例如 v _{d 2})、第二交軸電流(例如 i _{q 2})及第二交軸電壓(例如 v _{q 2})。 When the controller 130 determines that the motor device 150 is maintained at the second steady state (eg, the rotation speed of the motor 152 is maintained at the second rated rotation speed for more than a second predetermined time and within a second error range), the controller 130 receives the three-phase current The current detection values corresponding to the values i _a , _ib , and _ic (for example,

,

,

) to obtain and store the second steady state data. In this embodiment, the second steady-state data may include a second direct-axis current (eg, i _{d 2} ), a second direct-axis voltage (eg, v _{d 2} ), a second quadrature-axis current (eg, i _{q 2} ), and a second Two quadrature axis voltages (eg v _{q 2} ).

After the controller 130 obtains the first steady state data and the second steady state data, the controller 130 can obtain and store the equivalent magnetic flux according to the first steady state data and the second steady state data.

In this embodiment, the voltage equation of the direct-axis (d-q-axis) axis of the motor 152 can be expressed as Equation (1):

(1)

(1)

為直軸(d軸)電壓，

為交軸(q軸)電壓，

為定子電阻，

為直軸電流，

為交軸電流，

為直軸電感，

為交軸電感，

為微分運算子，

為馬達152之電機角速度，

為等效磁通量。 in,

is the direct-axis (d-axis) voltage,

is the quadrature axis (q axis) voltage,

is the stator resistance,

is the direct axis current,

is the quadrature current,

is the direct-axis inductance,

is the quadrature inductance,

is the differential operator,

is the motor angular velocity of the motor 152,

is the equivalent magnetic flux.

When the motor 152 runs to a steady state (for example, the rotational speed of the motor 152 maintains the rated rotational speed within the error range), the equation (1) can be rewritten as the equation (2), as shown below:

(2)

(2)

In addition, under a fixed load and at different rotational speeds (eg, the first rated rotational speed and the second rated rotational speed), the quadrature axis voltage (eg, the first quadrature axis voltage of the first steady-state data and the second quadrature axis voltage of the second steady-state data) (3a) and (3b) can be obtained from equation (2), as shown below:

(3a)

(3a)

(3b)

(3b)

為第一交軸電壓，

為第一交軸電流，

為第一額定轉速，

為第一直軸電流，

為第二交軸電壓，

為第二交軸電流，

為第二額定轉速，

為第二直軸電流。 in,

is the first quadrature axis voltage,

is the first quadrature axis current,

is the first rated speed,

is the first straight axis current,

is the second quadrature axis voltage,

is the second quadrature axis current,

is the second rated speed,

is the second direct axis current.

與第二交軸電壓

相減，亦即將式(3a)與式(3b)相減，以得到式(4)，如下所示： Next, the first quadrature axis voltage obtained at the two rotational speed operating points

with the second quadrature axis voltage

Subtraction, that is, subtracting Equation (3a) from Equation (3b) to obtain Equation (4), is as follows:

(4)

(4)

≈第二交軸電流

及第一直軸電流

≈第二直軸電流

，可以將式(4)簡化為式(5)，如下所示： When the first quadrature axis current

≈Second quadrature axis current

and the first straight axis current

≈Second axis current

, Equation (4) can be simplified to Equation (5), as follows:

(5)

(5)

Next, Equation (5) can be rewritten into Equation (6) in order to estimate the equivalent magnetic flux.

(6)

(6)

為等效磁通量。也就是說，控制器130可以依據式(6)，以估測出等效磁通量，並儲存等效磁通量。 in,

is the equivalent magnetic flux. That is, the controller 130 can estimate the equivalent magnetic flux according to equation (6), and store the equivalent magnetic flux.

Further, if the direct-axis current (for example, the first direct-axis current i _{d 1} ) is controlled to be zero, equation (6) can be simplified to equation (7), as shown below:

(7)

(7)

可以由不同額定轉速(例如第一額定轉速與第二額定轉速)與其對應的交軸電壓(第一交軸電壓與第二交軸電壓)計算而得，而可以不使用到與馬達152相關的電機參數(例如直軸電感

)，以增加檢測上的便利性及準確性。 That is to say, the controller 130 can also estimate the equivalent magnetic flux according to equation (7). It can be seen from equation (7) that the equivalent magnetic flux

It can be calculated from different rated speeds (for example, the first rated speed and the second rated speed) and their corresponding quadrature voltages (the first quadrature voltage and the second quadrature voltage), without using the motor 152-related voltage. Motor parameters (such as direct shaft inductance

) to increase the convenience and accuracy of detection.

In this way, by estimating the equivalent magnetic flux corresponding to the motor 152 by the controller 130, the operating state of the motor 152 can be effectively determined, that is, whether the temperature of the rotor of the motor 152 is too high, or whether the motor 152 is demagnetized. For example, when the equivalent magnetic flux is lower than a predetermined threshold, it means that the temperature of the rotor of the motor 152 is too high, or the motor 152 has been demagnetized. On the contrary, when the first magnetic flux is not lower than the preset threshold, it means that the temperature of the rotor of the motor 152 is not too high, or the motor 152 is not demagnetized.

In some embodiments, the controller 130 may adjust a control command to the inverter 151 according to the motor position signal, the first steady state data and the second steady state data, so that the inverter 151 changes the three-phase current value to drive the motor 152 . As shown in FIG. 1, the controller 130 may include a speed controller 131, a current controller 132, a modulation unit 133, a speed calculator 134, a three-phase-to-two-phase converter 135, and an estimation unit 136. However, the present invention implements the The example is not limited to this.

與馬達152的轉速，並依據速度命令

與馬達152的轉速，產生電流命令。電流控制器132耦接速度控制器131，接收速度控制器131所產生之電流命令、直軸電流(例如第一直軸電流 i _{d 1}或第二直電流 i _{d 2})與交軸電流(例如第一交軸電流 i _{q 1}或第二交軸電 i _{q 1})，以產生直軸電壓(例如第一直軸電壓 v _{d 1}或第二直軸電壓 v _{d 2})與交軸電壓(例如第一交軸電壓 v _{q 1}或第二交軸電壓 v _{q 2})。此外，當電流感測裝置120感測三相電流值 i _a 、 i _b 、 i _c 時，電流感測裝置120輸出三相電流值 i _a 、 i _b 、 i _c 的電流偵測值(例如

、

、

)給三相轉兩相轉換器135，並且三相轉二相轉換器135將三相電流值 i _a 、 i _b 、 i _c 的電流偵測值(例如

、

、

)轉換成直軸電流(例如第一直軸電流 i _{d 1}或第二直電流 i _{d 2})與交軸電流(例如第一交軸電流 i _{q 1}或第二交軸電 i _{q 1})。 Speed controller 131 may receive speed commands

and the speed of the motor 152, and according to the speed command

In conjunction with the rotational speed of the motor 152, a current command is generated. The current controller 132 is coupled to the speed controller 131, and receives the current command generated by the speed controller 131, the direct-axis current (eg, the _first direct-axis current _id1 or the _second direct-axis current _id2 ) and the quadrature-axis current (eg, the first quadrature axis current i _{q 1} or the second quadrature axis current i _{q 1} ) to generate the direct axis voltage (eg the first quad axis voltage v _{d 1} or the second quad axis voltage v _{d 2} ) and the quadrature axis voltage (eg _first quadrature voltage _vq1 or _second quadrature voltage _vq2 ). In addition, when the current sensing device 120 senses the three-phase current values _ia , _ib , _ic , the current sensing device 120 outputs the current detection values of the three-phase current values _ia , _ib , _ic (for example,

,

,

) to the three-phase to two-phase converter 135, and the three-phase to two-phase converter 135 converts the current detection values of the three-phase current values _ia , _ib , _ic (eg

,

,

) into a direct-axis current (eg, a first direct-axis current _{id 1} or a second direct-axis current _{id 2} ) and a quadrature-axis current (eg, the first quadrature-axis current i _{q 1} or the second quad-axis current i _{q 1} ).

The modulation unit 133 is coupled to the current controller 132 and receives the direct-axis voltage (eg, the first direct-axis voltage v _{d 1} or the second direct-axis voltage v _{d 2} ) and the quadrature-axis voltage (eg, the first direct-axis voltage v d 2 ) generated by the current controller 132 The quadrature axis voltage v _{q 1} or the second quadrature axis voltage v _{q 2} ), and three-phase to two-phase conversion and pulse width modulation are performed on the direct axis voltage and the quadrature axis voltage to generate control commands, and provide the control commands to Inverter 151. Next, the inverter 151 can output the three-phase current values _ia , _ib , _ic according to the control command generated by the modulation unit 133 to drive the motor 152 to operate.

、

、

)，並將三相電流值 i _a 、 i _b 、 i _c 的電流偵測值(例如

、

、

)轉換成二相的直軸電流(例如第一直軸電流 i _{d 1}或第二直電流 i _{d 2})與交軸電流(例如第一交軸電流 i _{q 1}或第二交軸電 i _{q 1})。 The speed calculator 134 is coupled to the encoder 110 , receives the motor position signal output by the encoder 110 , and calculates the motor position signal to generate the corresponding rotational speed of the motor 152 . The three-phase to two-phase converter 135 is coupled to the current sensing device 120 , and receives current detection values of three-phase current values _ia , _ib , and _ic generated by the current sensing device 120 (eg,

,

,

), and convert the current detection values of the three-phase current values i _a , _ib , _ic (for example,

,

,

) into a two-phase direct-axis current (such as the first direct-axis current _{id 1} or the second direct-axis current _{id 2} ) and the quadrature-axis current (such as the first quadrature-axis current i _{q 1} or the second quad-axis current i _{q 1} ).

The estimation unit 136 is coupled to the current controller 132 , the three-phase to two-phase converter 135 and the speed calculator 134 . The first direct-axis voltage, the first quadrature-axis voltage, the second direct-axis voltage, the second quadrature-axis voltage, and the first direct-axis current, the first quadrature-axis current, and the second direct-axis current provided by the three-phase-to-two-phase converter 135 Axial current and second quadrature axis current.

The estimating unit 136 can determine whether the motor device 150 is maintained in the first steady state (eg, determine whether the rotational speed of the motor 152 is maintained at the first rated rotational speed exceeding the first preset time and within the first error range), and the estimating unit 136 It is determined that the motor device 150 is maintained in the first steady state (for example, the rotational speed of the motor 152 is maintained at the first rated rotational speed exceeding the first pre-processing time and within the first error range), and the estimation unit 136 may store the first steady state (for example, The rotational speed of the motor 152 is maintained at the first steady state data corresponding to the first rated rotational speed).

In addition, the estimating unit 136 can also determine whether the motor device 150 is maintained in the second steady state (eg, determine whether the rotation speed of the motor 152 is maintained at the second rated rotation speed for more than a second predetermined time and within a second error range), and if The estimating unit 136 determines that the motor device 150 is maintained in the second steady state (for example, the rotational speed of the motor 152 is maintained at the second rated rotational speed exceeding the second preset time and within the second error range), and the estimating unit 136 may store the second The second steady state data corresponds to the steady state (eg, the rotational speed of the motor 152 is maintained at the second rated rotational speed). Next, the estimation unit 136 can obtain and store the equivalent magnetic flux according to the first steady state data and the second steady state data.

、

、

)，更新第一穩態資料及第二穩態資料，且重新地計算並儲存等效磁通量以生成多個等效磁通量。在本實施例中，上述多個等效磁通量的計算方式也可以利用式(6)或式(7)計算而得。 In some embodiments, the controller 130 may also repeatedly generate control commands to the inverter 151 to repeatedly drive the motor 152 to maintain the first steady state and the second steady state, and the controller 130 may determine the three-phase current value i according to the Current detection values corresponding to _a , _ib , and _ic (for example,

,

,

), update the first steady state data and the second steady state data, and recalculate and store the equivalent magnetic fluxes to generate a plurality of equivalent magnetic fluxes. In this embodiment, the calculation methods of the above-mentioned multiple equivalent magnetic fluxes can also be calculated by using the formula (6) or the formula (7).

Next, the controller 130 calculates the magnetic flux variation according to the plurality of equivalent magnetic fluxes. In some embodiments, the controller 130 can extract the minimum value and the maximum value from the above-mentioned multiple equivalent magnetic fluxes. That is, the controller 130 may compare a plurality of equivalent magnetic fluxes to obtain a minimum value and a maximum value. Afterwards, the controller 130 may calculate the magnetic flux variation according to the minimum and maximum values of the above-mentioned multiple equivalent magnetic fluxes.

In addition, in some embodiments, the controller 130 can extract the initial value and the final value from the above-mentioned multiple equivalent magnetic fluxes. That is, the controller 130 can sort the multiple equivalent magnetic fluxes to obtain the initial value and the final value. Afterwards, the controller 130 may calculate the magnetic flux variation according to the initial and final values of the plurality of equivalent magnetic fluxes. In this embodiment, the amount of magnetic flux change can be calculated using formula (8), as shown below:

(8)

(8)

為磁通變化量，

為最初值，

為最末值。 in,

is the change in magnetic flux,

is the initial value,

is the final value.

After the controller 130 calculates the magnetic flux variation, the controller 130 may issue a demagnetization warning according to the comparison result between the magnetic flux variation and the demagnetization warning value to determine whether the motor 152 is demagnetized. In this embodiment, the demagnetization warning value can be adjusted by the user according to his needs, such as 5% and 10%, but the embodiment of the present invention is not limited thereto.

For example, the controller 130 can compare the magnetic flux change with the demagnetization warning value to determine whether the magnetic flux change is greater than or equal to the demagnetization warning value (eg, determine whether the magnetic flux change is greater than 5%, 10%) and generate Comparing results. When the comparison result is that the magnetic flux variation is less than the demagnetization warning value, the controller 130 does not issue a demagnetization warning. In this way, it can be determined that the motor 152 is not demagnetized, and the controller 130 can continue the detection operation of the magnetic flux variation or end the detection operation. When the comparison result is that the magnetic flux variation is greater than or equal to the demagnetization warning value, the controller 130 will issue a demagnetization warning. In this way, the controller 130 can determine that the motor 152 is demagnetized, perform a demagnetization operation, and issue a demagnetization warning signal. In this way, the user can know that the motor 152 is demagnetized through the demagnetization warning signal, so as to repair or replace the motor 152 .

In other embodiments, the controller 130 includes a storage unit (not shown), so the controller 130 can store the calculated equivalent magnetic flux in the storage unit. The storage unit may be a memory, an electronically erasable read-only memory (EEPROM), or the like.

With the description of the above embodiments, the embodiments of the present invention provide a method for detecting demagnetization of a motor. FIG. 4 is a flowchart of a motor demagnetization detection method according to an embodiment of the present invention. The motor demagnetization detection method of this embodiment is used to detect a motor device. In step S402, the rotation angle of the motor device is measured by the encoder.

In step S404, the three-phase current value of the motor device is measured by the current sensing device. In step S406, the rotation speed of the motor device is calculated according to the rotation angle. In step S408, when it is determined according to the rotational speed that the motor device is maintained in the first steady state, the three-phase current value is received to obtain and store the first steady state data.

In step S410, when it is determined according to the rotational speed that the motor device is maintained in the second steady state, the three-phase current value is received to obtain and store the second steady state data. In step S412, the equivalent magnetic flux is calculated and stored according to the first steady state data and the second steady state data.

In step S414, the motor device is repeatedly driven to maintain the first steady state and the second steady state, the first steady state data and the second steady state data are updated according to the three-phase current value, and the equivalent magnetic flux is recalculated and stored to generate multiple equivalent magnetic fluxes. In step S416, the magnetic flux variation is calculated according to the plurality of equivalent magnetic fluxes. In step S418, a demagnetization warning is issued according to the comparison result between the magnetic flux change amount and the demagnetization warning value.

In this embodiment, the first steady-state data may include a first straight-axis current, a first straight-axis voltage, a first quadrature-axis current, and a first quadrature-axis voltage. The second steady state data may include a second direct axis current, a second direct axis voltage, a second quadrature axis current, and a second quadrature axis voltage.

Further, in some embodiments, step S416 may include capturing the minimum value and maximum value of a plurality of equivalent magnetic fluxes, and calculating the magnetic flux variation according to the minimum value and the maximum value. In some embodiments, step S416 may include capturing the initial and final values of a plurality of equivalent magnetic fluxes, and calculating the magnetic flux variation according to the initial and final values. In some embodiments, step S418 may include issuing a demagnetization warning when the comparison result is that the magnetic flux change is greater than or equal to the demagnetization warning value; when the comparison result is that the magnetic flux change is less than the demagnetization warning value, not issuing a demagnetization warning.

It is worth noting that the sequence of the steps in FIG. 4A is only used for illustration purposes, and is not used to limit the sequence of the steps of the embodiment of the present invention, and the sequence of the above steps can be changed by users according to their needs. Also, additional steps may be added or fewer steps may be used without departing from the spirit and scope of the present invention.

FIG. 5 is a waveform diagram of the rotational speed of the motor and the quadrature axis current when the motor demagnetization detection device according to an embodiment of the present invention drives the motor. In FIG. 7, the curve S1 represents the speed of the motor 152, the curve S2 represents the quadrature axis current, the symbol Speed1 represents the first rated speed, the symbol Speed2 represents the second rated speed, and the symbols T1 to T5 represent time. In addition, in this embodiment, the motor 152 is a motor of an elevator system, and the elevator car rises from the first floor to the fifth floor, for example.

At time T1, when the elevator car starts to run from the 1st floor, the motor braking device releases the motor 152, and the current value of the quadrature current S1 increases, so that the motor 152 starts to run and accelerate. Next, at time T2, when the elevator car reaches floors 2-3, the rotational speed of the motor 152 will reach and maintain the first rated rotational speed Speed1, that is, the motor device 150 is maintained in the first steady state. At this time, the controller 130 of the motor demagnetization detection apparatus 100 can obtain and store the first steady-state data. After that, at time T3, after the elevator car reaches the third floor, the current value of the quadrature axis current S1 decreases, and the motor 152 starts to decelerate. Next, at time T4, the rotational speed of the motor 152 will reach and maintain the second rated rotational speed Speed2, that is, the motor device 150 is maintained in the second steady state. At this time, the controller 130 of the motor demagnetization detection device 100 can obtain and store the second steady-state data. Finally, at time T5, when the elevator car reaches the 5th floor, the motor braking device will clamp the motor 152, stop the motor 152 and reduce the rotation speed of the motor 152 to zero, so that the elevator car is maintained on the 5th floor.

To sum up, the motor demagnetization detection method and the motor demagnetization detection device disclosed in the present invention obtain and store the first stable state by receiving three-phase current values when it is determined that the motor device is maintained in the first steady state according to the rotational speed of the motor device. state data, when it is judged that the motor device is maintained in the second steady state according to the rotational speed of the motor device, the three-phase current value is received to obtain and store the second steady state data, and calculated and calculated according to the first steady state data and the second steady state data. Store the equivalent magnetic flux, repeatedly drive the motor device to maintain the first steady state and the second steady state, update the first steady state data and the second steady state data according to the three-phase current value, and recalculate and store the equivalent The magnetic flux is used to generate a plurality of equivalent magnetic fluxes, and the variation of the magnetic flux is calculated according to the equivalent magnetic flux, and then a demagnetization warning is issued according to the comparison result of the variation of the magnetic flux and the demagnetization warning value. In this way, the magnetic flux can be effectively estimated and the magnetic flux estimation error caused by the nonlinear characteristics of the integrated circuit can be reduced, so as to increase the accuracy of detecting the demagnetization phenomenon, and the motor parameters (such as d) related to the motor can be omitted. shaft inductance) to increase the convenience and accuracy of detection.

Although the present invention is disclosed above by the embodiments, it is not intended to limit the scope of the present invention. Anyone with ordinary knowledge in the technical field can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be determined by the scope of the appended patent application.

:速度命令 i _a , i _b , i _c :三相電流值

,

,

:電流偵測值 v _{q 1}:第一交軸電壓 v _{q 2}:第二交軸電壓 v _{d 1}:第一直軸電壓 v _{d 2}:第二直軸電壓 i _{q 1}:第一交軸電流 i _{q 2}:第二交軸電流 i _{d 1}:第一直軸電流 i _{d 2}:第二直軸電流 S1:馬達的速度 S2:交軸電流 Speed1:第一額定轉速 Speed2:第二額定轉速 T1~T5:時間 S402~S418:步驟100: Motor demagnetization detection device 110: Encoder 120: Current sensing device 130: Controller 131: Speed controller 132: Current controller 133: Modulation unit 134: Speed calculator 135: Three-phase to two-phase converter 136 : Estimation unit 150 : Motor device 151 : Inverter 152 : Motor 153 : Rectifier 210, 220, 310, 320, 330: Current sensor

: Speed command i _a , i _b , _ic : Three-phase current value

,

,

: current detection value v _{q 1} : first quadrature-axis voltage v _{q 2} : second quad-axis voltage v _{d 1} : first quad-axis voltage v _{d 2} : second quad-axis voltage i _{q 1} : first quad-axis current _{i q 2} : the second quadrature axis current id 1 : the first quadrature axis current id ₂ : the second quadrature axis current S1 : the speed of the motor S2 : the quadrature axis current _Speed1 : the first rated speed _Speed2 : the second rated speed T1 ~T5: Time S402~S418: Step

FIG. 1 is a schematic diagram of a motor demagnetization detection device according to an embodiment of the present invention. FIG. 2 is a schematic diagram of a current sensing device according to an embodiment of the present invention. FIG. 3 is a schematic diagram of a current sensing device according to another embodiment of the present invention. FIG. 4 is a flowchart of a motor demagnetization detection method according to an embodiment of the present invention. FIG. 5 is a waveform diagram of the rotational speed of the motor and the quadrature axis current when the motor demagnetization detection device according to an embodiment of the present invention drives the motor.

S402~S418: Steps

Claims (12)

A motor demagnetization detection method for detecting a motor device, wherein the motor demagnetization detection method comprises: measuring a rotation angle of the motor device by an encoder; measuring the three-phase current value of the motor device by a current sensing device; calculating a rotational speed of the motor device according to the rotation angle; When judging that the motor device is maintained in a first steady state according to the rotational speed, receiving the three-phase current value to obtain and store a first steady state data; When judging that the motor device is maintained in a second steady state according to the rotational speed, receiving the three-phase current value to obtain and store a second steady state data; calculating and storing an equivalent magnetic flux according to the first steady state data and the second steady state data; Repeatedly driving the motor device to maintain the first steady state and the second steady state, updating the first steady state data and the second steady state data according to the three-phase current value, and recalculating and storing the effective magnetic flux to generate multiple equivalent magnetic fluxes; calculating a magnetic flux variation according to the plurality of equivalent magnetic fluxes; and A demagnetization warning is issued according to a comparison result between the magnetic flux change amount and a demagnetization warning value. The motor demagnetization detection method according to claim 1, wherein a minimum value and a maximum value of the plurality of equivalent magnetic fluxes are extracted, and the magnetic flux variation is calculated according to the minimum value and the maximum value. The motor demagnetization detection method as claimed in claim 1, wherein an initial value and a final value of the plurality of equivalent magnetic fluxes are extracted, and the magnetic flux variation is calculated according to the initial value and the final value. The motor demagnetization detection method according to claim 1, wherein the demagnetization warning is issued when the comparison result is that the magnetic flux variation is greater than or equal to the demagnetization warning value. The motor demagnetization detection method according to claim 4, wherein when the comparison result is that the magnetic flux variation is less than the demagnetization warning value, the demagnetization warning is not issued. A motor demagnetization detection device for detecting a motor device, wherein the motor demagnetization detection device comprises: an encoder for measuring a rotation angle of the motor device; a current sensing device for measuring the three-phase current value of the motor device; a controller, coupled to the encoder and the current sensing device; Wherein, the controller calculates a rotational speed of the motor device according to the rotation angle; Wherein, when the controller determines that the motor device is maintained in a first steady state according to the rotational speed, the controller receives the three-phase current value to obtain and store a first steady state data; Wherein, when the controller determines that the motor device is maintained in a second steady state according to the rotational speed, the controller receives the three-phase current value to obtain and store a second steady state data; Wherein, the controller calculates and stores an equivalent magnetic flux according to the first steady state data and the second steady state data; The motor device is repeatedly driven to maintain the first steady state and the second steady state, the controller updates the first steady state data and the second steady state data according to the three-phase current value, and recalculates and storing the equivalent magnetic flux to generate a plurality of equivalent magnetic fluxes; The controller calculates a magnetic flux variation according to the plurality of equivalent magnetic fluxes, and issues a demagnetization warning according to a comparison result between the magnetic flux variation and a demagnetization warning value. The motor demagnetization detection device of claim 6, wherein the controller captures a minimum value and a maximum value of the plurality of equivalent magnetic fluxes, and the controller calculates the magnetic flux according to the minimum value and the maximum value pass change. The motor demagnetization detection device of claim 6, wherein the controller captures an initial value and a final value of the plurality of equivalent magnetic fluxes, and the controller calculates the value according to the initial value and the final value The amount of change in the magnetic flux. The motor demagnetization detection device according to claim 6, wherein when the comparison result is that the magnetic flux variation is greater than or equal to the demagnetization warning value, the controller issues the demagnetization warning. The motor demagnetization detection device as claimed in claim 9, wherein when the comparison result is that the magnetic flux variation is less than the demagnetization warning value, the controller does not issue the demagnetization warning. The motor demagnetization detection device as claimed in claim 6, wherein the current sensing device comprises two current sensors, and the two current sensors are respectively used for measuring a first phase current and a first phase current of the three-phase current value. a second-phase current, wherein the controller calculates a third-phase current of the three-phase current value according to the first-phase current and the second-phase current. The motor demagnetization detection device according to claim 6, wherein the current sensing device comprises three current sensors, and the three current sensors respectively measure a first phase current and a second phase current of the three-phase currents. phase current and a third phase current.

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