TWI713298B - Electric machine control system and control method thereof - Google Patents

Abstract

An electric machine control system of a motor, includes a voltage detector, a power module, a current detector and a controller. The voltage detector detects a bus voltage to generate a voltage detection signal. The power module generates a first phase current, a second phase current, and a third phase current to drive the motor according to the bus voltage and a PWM signal respectively. The current detector detects at least two of the set of the first phase current, the second phase current and the third phase current to generate the current detection signal. When the motor is in a steady state, and the motor is blocked, the controller calculates a DC offset error of the motor according to the voltage detection signal and the current detection signal.

Description

Motor control system and its control method

The present invention relates to a motor control system and a control method thereof, and particularly relates to a motor control system and a control method thereof for calculating DC offset errors.

In motor control applications, it is desirable to maintain torque accuracy within a strict range, such as +/-5%. However, the torque is often not directly measured, but a predicted value generated by measuring the three-phase current and estimated motor parameters. Therefore, having accurate current measurements and estimated motor parameters helps maintain strict torque requirements.

In addition, since there is a DC offset error between the measured current and the actual current, in order to predict the accurate actual current, it is necessary to estimate the DC offset error.

In view of this, a motor control system is suitable for a motor and includes a voltage detector, a power module, a current detector, and a controller. The voltage detector detects a bus voltage and generates a voltage detection signal. The power module generates a first phase current, a second phase current, and a third phase current according to the bus voltage and a pulse width modulation signal, wherein the first phase current, the second phase current, and The third phase current is used to drive the motor. The current detector is used for detecting at least two of the first phase current, the second phase current, and the third phase current to generate a current detection signal. The controller judges whether the motor is operating in a steady state according to the current detection signal. When it is confirmed that the motor is operating in the steady state, it is judged whether the speed of one of the motors is zero at this time, and when it is confirmed that the speed is zero, The motor is in a locked-rotor state. At this time, the controller calculates the constant value of the motor based on the voltage detection signal generated by the voltage detector and the current detection signal generated by the current detector. Flow offset error.

According to an embodiment of the present invention, the controller generates a first axis current and a second axis current according to the current detection signal, and according to the voltage detection signal, the first axis current, and the second axis current , Respectively generate a first axis voltage and a second axis voltage.

According to an embodiment of the present invention, the above-mentioned motor control system further includes a power rectifier circuit and a pulse width modulation controller. The power rectifier circuit converts a supply voltage into the bus voltage, wherein the supply voltage is selected from any one of a three-phase AC voltage, a single-phase AC voltage, and a DC voltage. The pulse width modulation controller generates the pulse width modulation signal according to the first axis voltage and the second axis voltage.

According to an embodiment of the present invention, the controller sets the second axis voltage to zero, and performs current control twice to generate a first axis first voltage and a first axis second voltage to the pulse width adjustment. The controller is changed so that the motor generates a first-axis first measurement current corresponding to the first voltage of the first shaft, and generates a first-axis second measurement current corresponding to the second voltage of the first shaft, wherein the control The device further calculates the stator resistance according to a voltage difference and a current difference, wherein the voltage difference is the difference between the first voltage of the first axis and the second voltage of the first axis, and the current difference is the first voltage of the first axis. A measurement current and the difference between the first axis and the second measurement current, wherein the controller further uses the stator resistance, the first axis first voltage, the first axis second voltage, and the first axis first quantity The measured current and the second measured current of the first axis are used to calculate a DC offset error of the first axis. According to an embodiment of the present invention, the controller sets the voltage of the first axis to zero, and repeats the above-mentioned similar operation to calculate a DC offset error of the second axis. According to an embodiment of the present invention, the DC offset error of the first axis and the DC offset error of the second axis are used to calculate the DC offset error of the motor.

According to an embodiment of the present invention, the motor is a Y-connected motor, and when the motor is operating in the steady state, one of the first shaft current and the second shaft current is zero.

The present invention further provides a motor control method suitable for a motor, including the steps of: generating a first phase current, a second phase current, and a third phase current according to a bus voltage and a pulse width modulation signal, respectively, Used to drive the motor; detect the bus voltage to generate a voltage detection signal; detect at least two of the first phase current, the second phase current, and the third phase current to generate a current detection Measure signal; according to the current detection signal, determine whether the motor is operating in a steady state; when the motor is operating in the steady state, determine whether the speed of one of the motors is zero; and when the speed is zero, the motor is In a locked-rotor state, a calculation method is executed based on the voltage detection signal generated by the detection and the current detection signal generated by the detection.

According to an embodiment of the present invention, the control method further includes the steps of: respectively generating a first axis current and a second axis current according to the current detection signal; according to the voltage detection signal, the first axis current, and the above The second axis current generates a first axis voltage and a second axis voltage respectively; and the pulse width modulation signal is generated according to the first axis voltage and the second axis voltage.

According to an embodiment of the present invention, the above-mentioned control method further includes the step of: converting a supply voltage into the above-mentioned busbar voltage, wherein the above-mentioned supply voltage is selected from a three-phase AC voltage, a single-phase AC voltage, and a DC voltage. Either.

According to an embodiment of the present invention, the calculation method includes calculating a DC offset error of the first axis, and includes the steps of: setting the second axis voltage to zero; performing current control to generate a first axis first voltage, Make the motor generate a first-axis first measurement current corresponding to the first voltage of the first shaft; perform current control to generate a first-axis second voltage, so that the motor generates a first-axis second voltage corresponding to the first-axis second voltage The second measured current of the first axis; estimate the stator resistance according to a voltage difference and a current difference, wherein the voltage difference is the difference between the first voltage of the first axis and the second voltage of the first axis, the current difference Is the difference between the first measured current of the first axis and the second measured current of the first axis; and the use of the stator resistance, the first voltage of the first axis, the first measured current of the first axis, and the The second voltage of one axis and the second measured current of the first axis are calculated to calculate the DC offset error of the first axis. According to an embodiment of the present invention, the calculation method further includes calculating a DC offset error of the second axis, including the step of setting the voltage of the first axis to zero, and repeating the similar operation to calculate the second axis The above-mentioned DC offset error. According to an embodiment of the present invention, the calculation method further includes calculating a DC offset error of the motor by using the DC offset error of the first axis and the DC offset error of the second axis.

According to an embodiment of the present invention, the step of judging whether the motor is operating in the steady state according to the current detection signal includes: judging whether the variables of the first shaft current and the second shaft current are all zero; and when When the time variables of the first shaft current and the second shaft current are both zero, it is determined that the motor is operating in the steady state.

The following descriptions are examples of the present invention. Its purpose is to exemplify the general principles of the present invention, and should not be regarded as a limitation of the present invention. The scope of the present invention should be defined by the scope of the patent application.

It is worth noting that the content disclosed below can provide multiple embodiments or examples for practicing the different features of the present invention. The specific component examples and arrangements described below are only used to briefly illustrate the spirit of the present invention, and are not used to limit the scope of the present invention. In addition, the following description may reuse the same component symbols or words in multiple examples. However, the purpose of repeated use is only to provide a simplified and clear description, and is not used to limit the relationship between the multiple embodiments and/or configurations discussed below. In addition, the description of a feature connected to, coupled to, and/or formed on another feature described in the following specification may actually include a plurality of different embodiments, including direct contact with these features, or include other additional features. The features of are formed between these features, etc., so that these features are not in direct contact.

Fig. 1 shows a block diagram of a motor control system according to an embodiment of the invention. As shown in Figure 1, the motor control system 100 is used to drive the motor 10. The motor control system 100 includes a power rectifier circuit 110, a capacitor C, a voltage detector 120, a power module 130, a current detector 140, and a pulse width The controller 150 and the controller 160 are modulated.

The power rectifier circuit 110 is used to convert the supply voltage V _S into a bus voltage V _BUS , and apply the bus voltage V _BUS between the first terminal A and the second terminal B. The capacitor C is coupled between the first terminal A and the second terminal B to stabilize the bus voltage V _BUS . According to an embodiment of the present invention, the supply voltage V _S is a three-phase AC voltage. According to another embodiment of the present invention, the supply voltage V _S is a single-phase AC voltage. According to another embodiment of the present invention, the supply voltage V _S is a DC voltage.

The voltage detector 120 is coupled between the first terminal A and the second terminal B to detect the bus voltage V _BUS to generate a voltage detection signal S _V. According to an embodiment of the present invention, the controller 160 has a look-up table for mapping the voltage detection signal S _V to the voltage value of the bus voltage V _BUS . The power module 130 and the bus voltage V _BUS PWM signal S _PWM, respectively generate a first phase currents i _a, i _b, and a second phase current third phase current i _c, wherein a first phase current i _a, The second and third phase current i _b i _c-phase current to drive the motor 10.

The current detector 140 is used to detect at least two of the first phase current i _a , the second phase current i _b and the third phase current i _c to generate a current detection signal S _I. According to an embodiment of the present invention, when the motor 10 is a Y-connected motor, the current detector 140 can detect only one of the first phase current i _a , the second phase current i _b and the third phase current i _c Two of them, in order to reduce the cost of system construction.

According to an embodiment of the present invention, the current detector 140 can detect the first phase current i _a and the second phase current i _b to generate a current detection signal S _I. According to another embodiment of the present invention, a current detector 140 can detect phase currents of the second and third phase current i _b i _c, to generate a current detecting signal S _I. According to another embodiment of the present invention, a current detector 140 can detect phase currents i _a first and third phase current i _c, to generate a current detecting signal S _I. According to other embodiments of the present invention, the current detector 140 can also detect the first phase current i _a , the second phase current i _b and the third phase current i _c at the same time to generate the current detection signal S _I. To simplify the description, the current detector 140 will be used to detect the first phase current i _a and the second phase current i _b , and the corresponding current detection signal S _I includes the first measurement current i _am and the second measurement current. Take i _bm as an example for explanation.

According to an embodiment of the present invention, since the current detector 140 has a measurement error, the first phase current i _a , the second phase current i _b and the third phase current i _{c are} regarded as used to drive the motor 10 hereinafter. The actual current, and the first measurement current i _am , the second measurement current i _bm and the third measurement current i _{cm are} regarded as the current detected by the current detector 140. In the embodiment shown in FIG. 1, the current detection signal S _I includes a first measurement current i _am and a second measurement current i _bm .

The pulse width modulation controller 150 generates a pulse width modulation signal S _PWM according to the direct axis voltage V _d and the quadrature axis voltage V _q generated by the controller 160. As shown in FIG. 1, the controller 160 further includes a first control unit 161 and a second control unit 162.

The first control unit 161 can convert the three-phase current signal coordinates into a direct-axis current signal and a quadrature-axis current signal. In detail, the first control unit 161 calculates the first measurement current i _am and the second measurement current i _bm detected by the current detector 140 according to the current detection signal S _I and the rotation angle θ of the motor 10 Converted into direct-axis measurement current i _dm and quadrature-axis measurement current i _qm , the detailed conversion process will be described below.

The second control unit 162 may convert the direct-axis current signal and the quadrature-axis current signal input by the first control unit 161 into a direct-axis voltage signal and a quadrature-axis voltage signal. In detail, the second control unit 162 generates the direct-axis voltage V _d and the quadrature-axis voltage V _q according to the direct-axis measurement current i _dm , the quadrature-axis measurement current i _qm and the voltage detection signal S _V , and transmits them to the pulse The width modulation controller 150 is used to further control the first phase current i _a , the second phase current i _b and the third phase current i _c output by the power module 130.

（公式1） When the current is balanced, the sum of the first phase current i _a , the second phase current i _b and the third phase current i _c is zero, and the first measurement current i _am , the second measurement current i _bm and the third measurement The measured current i _cm is shown in the following formula 1, where I _S is the DC current, I _{a_err} and I _{b_err} are the DC offset errors, and θ is the angle of the motor 10:

(Formula 1)

（公式2-1）

（公式2-2）

（公式2-3）

（公式2-4） As shown in Fig. 1, the first control unit 161 uses Formula 2-1 and Formula 2-2 respectively according to the current detection signal S _{I to} convert the first measured current i _am , the second measured current i _bm and the third The measured current i _{cm is} converted into the first measured current i _am and the second measured current i _bm . Next, substitute formula 1 into formula 2-1 and formula 2-2 and expand formula 2-1 and formula 2-2 respectively to obtain formula 2-3 and formula 2-4.

(Formula 2-1)

(Formula 2-2)

(Formula 2-3)

(Formula 2-4)

According to an embodiment of the present invention, when the controller 160 determines that the motor 10 is operating in a steady state and the rotation speed of the motor 10 is zero, the controller 160 calculates the drive motor according to the voltage detection signal S _V and the current detection signal S _I One of 10 DC offset errors, where the DC offset errors include DC offset errors I _{a_err} and I _{b_err} . According to an embodiment of the present invention, the controller 160 calculates a DC offset error of the current detector 140. According to an embodiment of the present invention, when the controller 160 determines that the current variables of the first measurement current i _am and the second measurement current i _bm detected by the current detector 140 are zero, it determines that the motor 10 is Operate in steady state. The aforementioned time variable is zero, which means that the current values of the first measurement current i _am and the second measurement current i _bm remain constant within a specific measurement time, and the current value does not change due to time changes, ensuring that the motor 10 Operate in steady state.

According to another embodiment of the present invention, when the controller 160 determines that the time variables of the direct-axis measurement current i _dm and the quadrature-axis measurement current i _qm are zero, the controller 160 determines that the motor 10 is operating in a steady state. According to an embodiment of the present invention, when the motor 10 is the driving motor of an elevator, the mechanical brake of the elevator can be used to make the motor 10 enter a locked-rotor state, at which time the motor speed is zero.

（公式3） The voltage equations of the direct axis voltage V _d and the quadrature axis voltage V _q of the motor 10 are shown in the following formula 3, where rs is the stator resistance:

(Formula 3)

（公式4） When the rotation speed of the motor 10 is zero and it is operating in a steady state, the differential term and angular velocity in formula 3 are all zero, so formula 3 can be simplified to the following formula 4:

(Formula 4)

（公式5-1）

（公式5-2） The relationship between the direct axis measurement current i _dm and the quadrature axis measurement current i _qm and the actual direct axis current i _d and the quadrature axis actual current i _{q that} actually flow to the motor 10 are as shown in the following formula 5-1 and formula 5-2, respectively It is shown that the direct-axis actual current i _d and the quadrature-axis actual current i _q are the projections of the actual current of the motor 10 on the coordinates, Δi _dm is the direct-axis offset error, and Δi _qm is the quadrature-axis offset error. Move the straight axis offset error Δi _dm and quadrature axis offset error Δi _{qm in} formula 5-1 to the other side of the equal sign, and formula 5-2 can be obtained.

(Formula 5-1)

(Formula 5-2)

（公式6） After incorporating formula 5-2 into formula 4, the following formula 6 can be obtained:

(Formula 6)

According to an embodiment of the present invention, when the controller 160 calculates the DC offset error, it first sets one of the direct axis voltage V _d and the quadrature axis voltage V _q to zero to simplify the variable and facilitate the calculation, and then The other of the direct-axis voltage V _d and the quadrature-axis voltage V _q is set to zero. In order to simplify the description, the following will explain and explain that the controller 160 sets the quadrature axis voltage V _q to zero. According to an embodiment of the present invention, the direct axis voltage V _{d needs} to be set to zero again, and the above similar operations are repeated. , I will state first.

According to an embodiment of the present invention, when the controller 160 sets the quadrature axis voltage V _q to zero, the controller 160 generates the first straight axis voltage V _d1 and the second straight axis voltage V _d2 according to the voltage detection signal S _V , So that the pulse width modulation controller 150 generates corresponding pulse width modulation signals S _PWM corresponding to the first direct axis voltage V _d1 and the second direct axis voltage V _d2 , and the motor 10 generates a first corresponding to the first direct axis voltage V _d1 The direct-axis measurement current i _dm1 generates a second direct-axis measurement current i _dm2 corresponding to the second direct-axis voltage V _d2 . According to an embodiment of the present invention, the voltage value of the first direct axis voltage V _{d1 and} the voltage value of the second direct axis voltage V _d2 are different.

（公式7-1）

（公式7-2） The controller 160 substitutes the first direct-axis voltage V _d1 , the second direct-axis voltage V _d2 , the first direct-axis measurement current i _dm1 and the second direct-axis measurement current i _dm2 into Equation 6 and sets the quadrature axis voltage V _{q to} Is zero, the current control is performed twice to obtain the two current measurement results shown in the following formula 7-1 and formula 7-2 respectively, where V _d1 and V _d2 are the two-controlled direct-axis voltage V _d respectively The first voltage and the second voltage, where i _dm1 and i _dm2 are the first measured current and the second measured current of the direct axis measured twice:

(Formula 7-1)

(Formula 7-2)

（公式8-1）

（公式8-2） In order to calculate the stator resistance rs, the controller 160 subtracts formula 7-1 from formula 7-2 to obtain the following formula 8-1, where the value of V _d1 -V _d2 is a voltage difference, where i _d1 -i _d2 ( =i _dm1 -i _dm2 ) is a current difference. Then, after finishing formula 8-1, the following formula 8-2 is obtained. As shown in Equation 8-2, rs' is the estimated value of stator resistance.

(Formula 8-1)

(Formula 8-2)

（公式9） Then, the controller 160 further brings the rs' of the formula 8-2 into the formula 7-1 and the formula 7-2 to obtain the following formula 9:

(Formula 9)

（公式10-1）

（公式10-2） According to formula 9, the linear axis deviation error Δi _dm can be obtained as shown in the following formula 10-1 and formula 10-2:

(Formula 10-1)

(Formula 10-2)

According to an embodiment of the present invention, the direct axis deviation Δi _dm can be any one of formula 10-1 and formula 10-2. According to another embodiment of the present invention, the direct axis deviation Δi _dm may be the average value of formula 10-1 and formula 10-2.

Similarly, as mentioned above, the controller 160 in turn sets the direct axis voltage V _d to zero, and generates the first quadrature axis voltage V _q1 and the second quadrature axis voltage V _q2 according to the voltage detection signal S _V , and the current The detector 140 detects the first quadrature axis measurement current i _qm1 corresponding to the first quadrature axis voltage V _q1 , and detects the second quadrature axis measurement current i _qm2 corresponding to the second quadrature axis voltage V _q2 . According to an embodiment of the present invention, the voltage value of the first quadrature axis voltage V _{q1 and} the voltage value of the second quadrature axis voltage V _q2 are different.

（公式11-1）

（公式11-2） Next, the controller 160 uses the same method as described in formula 7-1 to formula 10-2 to calculate the quadrature axis deviation Δi _qm as shown in the following formula 11-1 and formula 11-2:

(Formula 11-1)

(Formula 11-2)

According to an embodiment of the present invention, the quadrature axis misalignment error Δi _qm can be any one of formula 11-1 and formula 11-2. According to another embodiment of the present invention, the quadrature axis misalignment error Δi _qm can be the average value of formula 11-1 and formula 11-2.

（公式12） Returning to formula 2-3 and formula 2-4, since I _{a_err} and I _{b_err are the projections} of the motor's DC offset error on the phases A and B, respectively, the direct axis offset error Δi _dm and the quadrature axis offset error Δi The relationship between _qm and I _{a_err} and I _{b_err} is shown in the following formula 12:

(Formula 12)

（公式13） Since formula 10-1 and formula 10-2 calculate the direct axis deflection error Δi _dm , and formula 11-1 and formula 11-2 calculate the quadrature axis deflection error Δi _qm , the direct axis deflection error Δi _dm and the cross The shaft offset error Δi _{qm is} taken into the following formula 13 to calculate the DC offset error I _{a_err} and I _{b_err of the motor} :

(Formula 13)

Figures 2A-2B show a flow chart of the control method according to an embodiment of the invention. The following description of the flowchart in Figures 2A-2B will be combined with the block diagram in Figure 1 for detailed description.

First, use the power rectifier 110 in Figure 1 to convert the supply voltage V _S into a bus voltage V _BUS (step S201), where the bus voltage V _{BUS is} applied between the first terminal A and the second terminal B, The capacitor C is coupled between the first terminal A and the second terminal B to stabilize the bus voltage V _BUS . According to an embodiment of the present invention, the supply voltage V _S is a three-phase AC voltage. According to another embodiment of the present invention, the supply voltage V _S is a single-phase AC voltage. According to another embodiment of the present invention, the supply voltage V _S is a DC voltage.

The voltage detector 120 is used to detect the bus voltage V _BUS to generate a voltage detection signal S _V (step S202). According to an embodiment of the present invention, the controller 160 has a look-up table for mapping the voltage detection signal S _V to the bus voltage V _BUS . Using the power module 130, according to the bus voltage V _BUS and the PWM signal S _PWM, respectively generate a first phase currents i _a, i _b, and a second phase current third phase current i _c (step S203), for Drive motor 10.

The current detector 140 is used to detect at least two of the first phase current i _a , the second phase current i _b and the third phase current i _c to generate a current detection signal SI (step S204 ). According to many embodiments of the present invention, when the motor 10 is a Y-connected motor, the current detector 140 can detect the first phase current i _a and the second phase current i _b , the second phase current i _b and the third phase current i _b. a first phase current or phase currents i _c i _a and i _c to any current in the third phase of a combination, to generate a current detecting signal S _I. According to other embodiments of the present invention, the current detector 140 can also detect the first phase current i _a , the second phase current i _b and the third phase current i _c at the same time to generate the current detection signal S _I.

Next, the controller 160 is used to generate the first axis current and the second axis current according to the current detection signal S _I (step S205). According to an embodiment of the present invention, the first axis current is the direct axis measurement current i _dm shown in Figure 1, and the second axis current is the quadrature axis measurement current i _qm . According to another embodiment of the present invention, the second axis current is the direct axis measurement current i _dm shown in Figure 1, and the first axis current is the quadrature axis measurement current i _qm .

In addition, the controller 160 is used to generate the first axis voltage and the second axis voltage according to the voltage detection signal S _V , the first axis current, and the second axis current (step S206 ). According to an embodiment of the present invention, when the first axis current system is the direct axis measurement current i _dm and the second axis current system is the quadrature axis measurement current i _qm , the first axis voltage system is the direct axis voltage V _d , The second axis voltage system is the quadrature axis voltage V _q . According to another embodiment of the present invention, when the second axis current system is the direct axis measurement current i _dm and the first axis current system is the quadrature axis measurement current i _qm , the second axis voltage system is the direct axis voltage V _d , The first axis voltage system is the quadrature axis voltage V _q .

Then, the controller 160 is further used to generate a pulse width modulation signal S _PWM according to the first axis voltage and the second axis voltage (step S207) to control the parameters of the motor 10.

The controller 160 determines whether the motor 10 is operating in a steady state according to the current detection signal S _I (step S208). According to an embodiment of the present invention, when the controller 160 of FIG. 1 determines that the current time variables of the first measurement current i _am and the second measurement current i _bm detected by the current detector 140 are zero, It means that the motor 10 is operating in a steady state. According to another embodiment of the present invention, when the controller 160 determines that the time variables of the direct axis measurement current i _dm and the quadrature axis measurement current i _qm (that is, the first axis current and the second axis current) are zero, It means that the motor 10 is operating in a steady state. According to many embodiments of the present invention, the controller 160 determines that the current values of the direct-axis measurement current i _dm and the quadrature-axis measurement current i _qm remain constant for a specific measurement time, and there is no current value due to time changes. Therefore, it is confirmed that the motor 10 is operating in a steady state.

When it is determined that the motor 10 is operating in a steady state, the controller 160 further determines whether the rotation speed of the motor 10 is zero (step S209). According to an embodiment of the present invention, when the motor 10 is the driving motor of an elevator, the mechanical brake of the elevator can be used to make the motor 10 enter a locked-rotor state, at which time the motor speed is zero. According to many embodiments of the present invention, when the rotation speed of the motor 10 is zero, it means that the angle θ of the motor 10 is a constant value.

When the motor 10 is operating in a steady state and the rotation speed of the motor 10 is zero, the controller 160 executes the calculation method (step S210) according to the voltage detection signal S _V and the current detection signal S _I , such as calculating the DC offset error. When it is judged as no in step S208 and step S209, it returns to step S203.

Fig. 3 shows a flowchart of the calculation method according to an embodiment of the invention. The calculation method 300 shown in FIG. 3 is used to calculate a DC offset error of the drive control motor 10. The following description of the calculation method 300 will be combined with the block diagram in FIG. 1 for detailed description.

First, the second axis voltage is set to zero (step S301). According to an embodiment of the present invention, the first axis voltage system is the direct axis voltage V _d , and the second axis voltage system is the quadrature axis voltage V _q . According to another embodiment of the present invention, the first axis voltage system is the quadrature axis voltage V _q , and the second axis voltage system is the direct axis voltage V _d .

Next, the first current control is performed, and the controller 160 generates the first voltage of the first axis, and correspondingly generates the first measured current of the first axis (step S302). According to an embodiment of the present invention, when the first-axis first voltage system is the direct-axis voltage V _d1 , the first-axis first measurement current system is the direct-axis first measurement current i _dm1 . According to another embodiment of the present invention, when the first axis first voltage system is the quadrature axis voltage V _q1 , the first axis first measured current system is the quadrature axis first measured current i _qm1 .

Next, the controller 160 performs a second current control to generate a second voltage of the first axis and correspondingly generate a second measured current of the first axis (step S303). According to an embodiment of the present invention, when the first axis second voltage system is the direct axis voltage V _d2 , the first axis second measurement current system is the direct axis second measurement current i _dm2 . According to another embodiment of the present invention, when the first axis second voltage system is the quadrature axis voltage V _q2 , the first axis second measurement current system is the direct axis second measurement current i _qm2 . It should be noted that the voltages of the two current controls are different, that is, the first voltage of the first axis and the second voltage of the first axis are different values.

Next, the controller 160 estimates the stator resistance based on the voltage difference and the current difference (step S304). According to an embodiment of the present invention, the voltage difference is the difference between the first voltage of the first axis and the second voltage of the first axis, and the current difference is the difference between the first measured current of the first axis and the second measured current of the first axis difference. According to an embodiment of the present invention, the controller 160 calculates the estimated stator resistance rs' using formula 8-2.

Next, the controller 160 uses the stator resistance, the first axis first voltage, the first axis first measured current, the first axis second voltage, and the first axis second measured current to calculate the DC offset of the first axis current Error (step S305). According to an embodiment of the present invention, when the first axis voltage system is the direct axis voltage V _d , the controller 160 uses formula 10-1 and formula 10-2 to calculate the direct axis deviation Δi _dm . According to an embodiment of the present invention, the straight-axis misalignment error Δi _dm can be any of formula 10-1 and formula 10-2. According to another embodiment of the present invention, the straight axis deviation Δi _dm may be the average value of the formula 10-1 and the formula 10-2.

Repeat the current control method similar to the above steps S301 to S305, that is, in this process, the controller 160 changes the first axis voltage to zero, and uses formula 11-1 and formula 11-2 to calculate the DC current of the second axis Offset error (step S306). According to an embodiment of the present invention, when the first axis voltage system is the direct axis voltage V _d and the second axis voltage system is the quadrature axis voltage V _q , the controller 160 uses formula 11-1 and formula 11-2 to calculate the Shaft misalignment error Δi _qm . According to an embodiment of the present invention, the quadrature axis misalignment error Δi _qm can be any one of formula 11-1 and formula 11-2. According to another embodiment of the present invention, the quadrature axis misalignment error Δi _qm can be the average value of formula 11-1 and formula 11-2.

In detail, according to other embodiments of the present invention, when the above steps S301 to S306 are continuously repeated to obtain the straight-axis misalignment error Δi _dm and the quadrature-axis misalignment error Δi _qm , the straight-axis misalignment error Δi _dm and the quadrature axis offset error Δi _{qm are put} into formula 13 to obtain the DC offset errors I _{a_err} and I _{b_err of the motor} (step S307).

The present invention proposes a method for calculating the DC offset error, so that the motor control system 100 can directly estimate the DC offset error, so that the motor control is more accurate and reliable.

The above are the summary features of the embodiment. Those with ordinary knowledge in the technical field should be able to easily use the present invention as a basis for design or adjustment to achieve the same purpose and/or achieve the same advantages of the embodiments described herein. Those with ordinary knowledge in the technical field should also understand that the same configuration should not deviate from the spirit and scope of this creation, and they can make various changes, substitutions and alterations without departing from the spirit and scope of this creation. The illustrative methods only represent exemplary steps, but these steps do not have to be performed in the order shown. Additional steps may be added, substituted, changed, and/or eliminated to adjust according to the situation and consistent with the spirit and scope of the disclosed embodiments.

10: Motor 100: Motor control system 110: Power rectifier circuit 120: Voltage detector 130: Power module 140: Current detector 150: Pulse width modulation controller 160: Controller 161: First control unit 162: The second control unit V _BUS : bus voltage A: first terminal B: second terminal C: capacitor V _S : supply voltage S _V : voltage detection signal S _PWM : pulse width modulation signal S _I : current detection Measurement signal i _a : first phase current i _b : second phase current i _c : third phase current i _am : first measurement current i _bm : second measurement current i _cm : third measurement current V _d : Direct axis voltage V _q : Quadrature axis voltage θ: Angle S201～S210: Step flow 300: Calculation method S301～S307: Step flow

Figure 1 shows a block diagram of a motor control system according to an embodiment of the invention; Figures 2A-2B show a flow chart of the control method according to an embodiment of the present invention; and Fig. 3 shows a flowchart of the calculation method according to an embodiment of the invention.

10: Motor

100: Motor control system

110: Power rectifier circuit

120: voltage detector

130: Power Module

140: current detector

150: Pulse width modulation controller

160: Controller

161: The first control unit

162: second control unit

V _BUS : bus voltage

A: First endpoint

B: second endpoint

C: Capacitance

V _S : supply voltage

S _V : Voltage detection signal

S _PWM : Pulse width modulation signal

i _a : first phase current

i _b : second phase current

i _c : third phase current

S _I : Current detection signal

i _am : the first measured current

i _bm : second measurement current

i _cm : third measurement current

V _d : Direct axis voltage

V _q : quadrature axis voltage

θ: Angle

Claims (14)

A motor control system suitable for a motor, including: A voltage detector detects a bus voltage and generates a voltage detection signal; A power module generates a first phase current, a second phase current, and a third phase current according to the bus voltage and a pulse width modulation signal, wherein the first phase current and the second phase current And the third phase current is used to drive the motor; A current detector for detecting at least two of the first phase current, the second phase current, and the third phase current to generate a current detection signal; and A controller determines whether the motor is operating in a steady state according to the current detection signal, when the motor is operating in the steady state, determines whether a speed of the motor is zero, and when the speed is zero, the motor Is in a locked-rotor state. At this time, the controller calculates a DC deviation of the motor based on the voltage detection signal generated by the voltage detector and the current detection signal generated by the current detector. Bit error. According to the motor control system described in claim 1, wherein the controller generates a first axis current and a second axis current according to the current detection signal, and according to the voltage detection signal, the first axis current And the second axis current respectively generates a first axis voltage and a second axis voltage. The motor control system described in item 2 of the scope of patent application also includes: A power rectifier circuit that converts a supply voltage into the busbar voltage, wherein the supply voltage is selected from any one of a three-phase AC voltage, a single-phase AC voltage, and a DC voltage; and A pulse width modulation controller generates the pulse width modulation signal according to the first axis voltage and the second axis voltage. The motor control system described in item 3 of the scope of patent application, wherein the controller sets the second shaft voltage to zero, and performs current control twice to generate a first shaft first voltage and a first shaft second voltage. Two voltages are applied to the pulse width modulation controller, so that the motor generates a first-axis first measurement current corresponding to the first voltage of the first axis, and generates a first-axis first measurement current corresponding to the second voltage of the first axis 2. Measuring current, wherein the controller further calculates the stator resistance according to a voltage difference and a current difference, wherein the voltage difference is the difference between the first voltage of the first axis and the second voltage of the first axis, the current The difference is the difference between the first measured current of the first axis and the second measured current of the first axis, wherein the controller further uses the stator resistance, the first voltage of the first axis, and the second voltage of the first axis , The first measured current of the first axis and the second measured current of the first axis, calculating a DC offset error of the first axis. The motor control system described in item 4 of the scope of patent application, wherein the controller sets the first shaft voltage to zero, and performs current control twice to generate a second shaft first voltage and a second shaft first voltage. Two voltages are applied to the pulse width modulation controller, so that the motor generates a second axis first measurement current corresponding to the second axis first voltage, and generates a second axis first measurement current corresponding to the second axis second voltage Two measurement currents, where the controller further uses the stator resistance, the second axis first voltage, the second axis second voltage, the second axis first measurement current, and the second axis second measurement current , Calculate the DC offset error of one of the second axis. The motor control system described in item 5 of the scope of patent application, wherein the DC offset error of the first axis and the DC offset error of the second axis are used to calculate the DC offset error of the motor. The motor control system described in item 1 of the scope of patent application, wherein the motor is a Y-connected motor, and when the motor is operating in the steady state, a time variable of the first shaft current and the second shaft current When one of the variables are all zero. A motor control method, suitable for a motor, includes the following steps: According to a bus voltage and a pulse width modulation signal, a first phase current, a second phase current, and a third phase current are respectively generated to drive the motor; Detect the bus voltage to generate a voltage detection signal; Detecting at least two of the first phase current, the second phase current, and the third phase current to generate a current detection signal; According to the current detection signal, determine whether the motor is operating in a steady state; When the motor is operating in the steady state, judging whether a rotation speed of the motor is zero; and When the rotation speed is zero, the motor is in a locked-rotor state. At this time, a calculation method is performed according to the voltage detection signal generated by the detection and the current detection signal generated by the detection. The control method described in item 8 of the scope of patent application further includes the following steps: Generate a first axis current and a second axis current respectively according to the current detection signal; Generate a first axis voltage and a second axis voltage according to the voltage detection signal, the first axis current, and the second axis current; and The pulse width modulation signal is generated according to the first axis voltage and the second axis voltage. For example, the control method described in item 9 of the scope of patent application further includes steps: A supply voltage is converted into the bus voltage, wherein the supply voltage is selected from any one of a three-phase AC voltage, a single-phase AC voltage, and a DC voltage. The control method described in item 9 of the scope of patent application, wherein the calculation method includes calculating the DC offset error of one of the first axis, including the following steps: Set the second axis voltage to zero; Performing current control to generate a first axis first voltage, so that the motor generates a first axis first measurement current corresponding to the first axis first voltage; Performing current control to generate a first axis second voltage, so that the motor generates a first axis second measurement current corresponding to the first axis second voltage; Estimate the stator resistance according to a voltage difference and a current difference, where the voltage difference is the difference between the first voltage of the first axis and the second voltage of the first axis, and the current difference is the first quantity of the first axis The difference between the measured current and the second measured current of the first axis; and Use the stator resistance, the first axis first voltage, the first axis first measured current, the first axis second voltage, and the first axis second measured current to calculate the DC offset of the first axis Bit error. The control method described in item 11 of the scope of patent application, wherein the calculation method further includes calculating a DC offset error of the second axis, including the following steps: Set the first axis voltage to zero; Performing current control to generate a second axis first voltage, so that the motor generates a second axis first measurement current corresponding to the second axis first voltage; Performing current control to generate a second axis second voltage, so that the motor generates a second axis second measurement current corresponding to the second axis second voltage; and Using the stator resistance, the second axis first voltage, the second axis first measured current, the second axis second voltage, and the second axis second measured current, calculate the DC offset of the second axis Bit error. As the control method described in item 12 of the scope of patent application, the calculation method further includes the steps: The DC offset error of the first axis and the DC offset error of the second axis are used to calculate a DC offset error of the motor. For the control method described in item 8 of the scope of patent application, the step of judging whether the motor is operating in the steady state according to the current detection signal includes: Determining whether one of the time variables of the first axis current and one of the second axis current variables are all zero; and When the time variable of the first shaft current and the time variable of the second shaft current are both zero, it is determined that the motor is operating in the steady state.

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