TWI587623B - Synchronous motor control circuit and control method - Google Patents

Description

Synchronous motor control circuit and control method

This case relates to a synchronous motor control method, and in particular to a synchronous motor control method for performing field weakening control.

Permanent magnet synchronous motors have energy-saving features such as high power density and good motor efficiency. With the awareness of environmental protection and energy conservation, permanent magnet synchronous motors have gradually replaced traditional motors and are used in various equipment applications.

In the drive control of the permanent magnet synchronous motor, the operating range of the permanent magnet synchronous motor can be expanded by the field weakening current. However, when the weak magnetic current is too much, the motor output torque is insufficient and the operating efficiency is not good. In contrast, when the weak magnetic current is insufficient, the speed cannot be increased, and the control is unstable. Therefore, how to improve the weak magnetic control strategy to improve the control stability of synchronous motors is an important research topic in the field.

One aspect of the present disclosure is a control method. The control method is for controlling a synchronous motor, wherein the control method comprises: calculating, by a maximum torque current ratio control unit, a first direct axis current command and an intersecting current command according to a frequency command and an electrical frequency of the synchronous motor When a feedback output voltage of the synchronous motor is greater than a voltage control level, a voltage weakening current command is output by a voltage control unit; and a feedforward control unit is based on the electrical frequency, a voltage standard level, and the The cross-axis current command calculates a weak magnetic current feedforward term; when the sum of the weak magnetic current command and the weak magnetic current feedforward term is less than the first direct-axis current command, the weak magnetic current command and the weak magnetic current are a sum of the feedforward terms to adjust the first direct axis current command to output a second direct axis current command; and a voltage command output unit to output a constant axis voltage command according to the second straight axis current command and the intersecting current command respectively With a cross-axis voltage command to control the synchronous motor.

In some embodiments, calculating the field weakening current feedforward by the feedforward control unit includes: obtaining a reference model according to a magnetic flux linkage parameter of the synchronous motor; and using the reference model according to the electrical frequency, the voltage target The standard bit and the quadrature current command calculate the field weakening current feedforward term.

In some embodiments, the control method further includes: calculating, by a voltage saturation adjustment unit, a frequency command correction term according to the quadrature current error value and an quadrature current error value, wherein the direct axis current error value is the second straight axis a difference between the current command and the constant-axis feedback current, the offset current error value being a difference between the cross-axis current command and a quadrature feedback current; and the voltage saturation adjustment unit adjusting the frequency command according to the frequency command correction term .

In some embodiments, the control method further includes: calculating, by a first computing unit, a difference between the weak magnetic current command and the weak magnetic current feedforward term and the first direct current command to obtain a field weakening current compensation The amount of the field weakening current compensation is limited by a limiting unit, wherein when the field weakening current compensation amount is greater than zero, the weakening current compensation amount output by the limiting unit is zero; The arithmetic unit corrects the first direct axis current command according to the limited field weak current compensation amount to output the second straight axis current command.

In some embodiments, the outputting the direct-axis voltage command and the cross-axis voltage command by the voltage command output unit includes: returning a current from the linear axis of the synchronous motor according to the second straight-axis current command by a third arithmetic unit Calculating a linear current error value; the constant axis current controller of the voltage command output unit outputs the direct axis voltage command according to the straight axis current error value; and the fourth arithmetic unit commands the synchronous motor according to the intersecting current command A quadrature axis feedback current calculates an axis current error value; and an on-axis current controller of the voltage command output unit outputs the cross-axis voltage command according to the cross-axis current error value.

In some embodiments, the control method further includes: receiving, by a first proportional controller of the voltage control unit, a DC bus voltage to output the voltage control level; and a second ratio of the feedforward control unit The controller receives the DC bus voltage to output the voltage standard bit.

Another aspect of the present disclosure is a synchronous motor control circuit. The synchronous motor control circuit includes: a maximum torque current ratio control unit configured to calculate a first direct current command and a cross current command according to a frequency command and an electrical frequency of a synchronous motor; and a voltage control unit Outputting a weak magnetic current command according to a feedback output voltage of the synchronous motor and a voltage control level; a feedforward control unit for calculating according to the electrical frequency, a voltage standard bit, and the cross current command a weak current current feedforward term; a current command compensation unit electrically coupled to the maximum torque current ratio control unit, the voltage control unit and the feedforward control unit for commanding the weak current command and the weak a magnetic current feedforward term adjusts the first direct current command to output a second direct current command; and a voltage command output unit electrically coupled to the current command compensation unit and the maximum torque current ratio control unit, And outputting a constant axis voltage command and a cross-axis voltage command respectively according to the second straight-axis current command and the cross-axis current command to control the synchronous motor.

In some embodiments, the synchronous motor control circuit further includes a voltage saturation adjustment unit, and the voltage saturation adjustment unit includes: a voltage saturation regulator for determining a difference between the second direct current command and the constant current feedback current. And calculating a frequency command correction term by the difference between the quadrature current command and a quadrature feedback current; and a frequency command operation unit for adjusting the frequency command according to the frequency command correction term.

In some embodiments, the current command compensation unit includes: a first operation unit, configured to calculate a difference between the weak magnetic current command and the weak magnetic current feed forward term and the first straight axis current command to obtain a a weak magnetic current compensation amount; a limiting unit configured to limit the weak magnetic current compensation amount, and when the weak magnetic current compensation amount is greater than zero, the weak magnetic current compensation amount output by the limiting unit is zero; And a second operation unit, configured to correct the first direct-axis current command output by the maximum torque-current ratio control unit according to the weak magnetic current compensation amount output by the limiting unit to output the second direct-axis current command.

In some embodiments, the feedforward control unit includes a reference model obtained from a magnetic flux linkage parameter of the synchronous motor, and the feedforward control unit calculates the field weakening current feed term by the reference model.

In summary, the synchronous motor control circuit of the present invention provides the weak magnetic current by the feedforward control combined with the voltage control unit and the motor reference model, which can take into account the fast response and stable operation of the controller.

Please refer to Figure 1. FIG. 1 is a schematic diagram of a synchronous motor control circuit 100 according to some embodiments of the present disclosure. In some embodiments, the synchronous motor control circuit 100 can output a d-axis voltage command Vd* and a q-axis voltage command Vq* to control a permanent magnet synchronous motor (PMSM). ). For example, the direct-axis voltage command Vd* and the cross-axis voltage command Vq* output by the synchronous motor control circuit 100 can be further converted into a three-phase voltage command of the synchronous motor via a Park's Transformation, and then transmitted through the corresponding driving circuit. Output drive signals (such as pulse width modulation signals, etc.) to drive the synchronous motor. In other words, the synchronous motor control circuit 100 can control the output voltage, the output current, the rotational speed, and the like of the synchronous motor by adjusting the direct-axis voltage command Vd* and the cross-axis voltage command Vq* of the output.

As shown in FIG. 1, in some embodiments, the synchronous motor control circuit 100 includes a maximum torque per ampere (MTPA) control unit 110, a voltage control unit 120, a feedforward control unit 130, and current command compensation. Unit 140 and voltage command output unit 150.

Specifically, in some embodiments, the maximum torque current ratio control unit 110 can calculate the torque required by the synchronous motor according to the frequency command ω _cmd and the electrical frequency ω _r of the synchronous motor, and pass the maximum torque current ratio control strategy. The first straight-axis current command Id _mtp and the cross-axis current command Iq _{cmd are} calculated to provide a maximum torque output for torque control of the synchronous motor.

In some embodiments, as the speed or load of the synchronous motor increases, the terminal voltage of the synchronous motor also increases. In order to avoid the phenomenon that the output voltage of the driving circuit is saturated and the speed cannot be improved or the control is unstable, the synchronous motor control circuit 100 can perform the field weakening control correspondingly to increase the operating range of the synchronous motor, so that the synchronous motor operates above the rated frequency.

Specifically, the synchronous motor control circuit 100 can calculate the current command required to operate in the field weakening control region through the voltage control unit 120 and the feedforward control unit 130. As shown in FIG. 1, the voltage control unit 120 is configured to output the field weakening current command Id _vc according to the feedback output voltage V _{fbk of the} synchronous motor and the voltage control level Vc. For example, in some embodiments, the feedback output voltage V _fbk can be calculated from the straight-axis voltage command Vd* and the cross-axis voltage command Vq* squared opening number. When the feedback output voltage V _{fbk is} higher than the voltage control level Vc, the voltage control unit 120 outputs the field weakening current command Id _vc .

The feedforward control unit 130 is configured to calculate the field weakening current feedforward term Id _ffd according to the electrical frequency ω _{r of the} synchronous motor, the voltage standard bit Vt, and the intersecting current command Iq _cmd . Specifically, the feedforward control unit 130 calculates the direct current of the synchronous motor in the current state through the reference model of the synchronous motor. In this way, by adding the weak magnetic current feedforward term Id _ffd and the weak magnetic current command Id _vc , the current command required in the field weakening control region can be obtained. The specific operation of the feedforward control unit 130 to calculate the field weakening current feedforward term Id _ffd will be described in detail in the following paragraphs with the drawings.

In some embodiments, the synchronous motor control circuit 100 can be judged by the current command compensation unit 140 to operate the synchronous motor in the MTPA control region or the field weakening control region. Structurally, the current command compensation unit 140 is electrically coupled to the maximum torque current ratio control unit 110, the voltage control unit 120, and the feedforward control unit 130. The current command compensation unit 140 is configured to adjust the first _direct axis current command Id _mtp according to the field weakening current command Id _vc output by the voltage control unit 120 and the field weakening current feed term Id _ffd output by the feedforward control unit 130. Thereby, the current command compensation unit 140 can output the adjusted second straight-axis current command Id _cmd . In this way, the second straight-axis current command Id _cmd and the cross-axis current command Iq _cmd can be output to the voltage command output unit 150.

In other words, the maximum torque current ratio control unit 110, the voltage control unit 120, the feedforward control unit 130, and the current command compensation unit 140 constitute a current command output unit that selectively outputs the second according to the operating state of the synchronous motor under cooperative operation. Straight axis current command Id _cmd and cross axis current command Iq _cmd . Under MTPA control, the second direct axis current command Id _cmd and the quadrature current command Iq _cmd may be current commands that provide a maximum torque to current ratio. On the other hand, under the field weakening control, the second direct-axis current command Id _cmd is corrected based on the field weakening current feedforward term Id _ffd and the field weakening current command Id _vc to suppress an increase in the output voltage of the synchronous motor. In this way, the synchronous motor can operate above the rated frequency.

Structurally, the voltage command output unit 150 is electrically coupled to the current command compensation unit 140 and the maximum torque current ratio control unit 110. The voltage command output unit 150 is configured to output a direct-axis voltage command Vd* and a cross-axis voltage command Vq* according to the second straight-axis current command Id _cmd and the cross-axis current command Iq _cmd to drive the synchronous motor.

In this way, through the cooperative operation of the above circuit unit, the synchronous motor control circuit 100 can output the direct-axis voltage command Vd* and the cross-axis voltage command Vq* to control the synchronous motor, and generate corresponding when the field weakening control is to be performed. Current command.

For convenience of explanation, the following paragraphs will be described in detail with reference to the embodiments, and the implementation manners of the respective functional units of the synchronous motor control circuit 100 will be described in detail. Please refer to Figure 2. FIG. 2 is a schematic diagram of a synchronous motor control circuit 100 according to some embodiments of the present disclosure.

As shown in FIG. 2, in some embodiments, the maximum torque current ratio control unit 110 includes an arithmetic unit 112, a speed controller 114, a direct current command calculation unit 116, and an intersecting current command calculation unit 118. For example, the arithmetic unit 112 may include a subtractor for calculating the frequency error value ω _err between the frequency command ω _cmd and the electrical frequency ω _{r of the} synchronous motor. The speed controller 114 can receive the frequency error value ω _err and calculate and output the torque command T _{cmd accordingly} . In this way, the direct-axis current command calculation unit 116 and the cross-axis current command calculation unit 118 can output the corresponding first _direct- axis current command Id _mtp and the cross-axis current command Iq _cmd according to the maximum torque-current ratio control strategy, respectively.

Moreover, in some embodiments, voltage control unit 120 includes a proportional controller 122, an arithmetic unit 124, and a voltage controller 126. The proportional controller 122 is configured to receive the DC bus voltage Vbus from the system DC bus and output the voltage control level Vc. The operation unit 124 is configured to calculate a difference between the voltage control level Vc and the feedback output voltage V _fbk (ie, the voltage error value V _err ) to determine whether the feedback output voltage V _fbk is greater than the voltage control level Vc. Thereby, the voltage controller 126 can output the corresponding field weak current command Id _vc according to the difference between the voltage control level Vc and the feedback output voltage V _fbk (ie, the voltage error value V _err ) to control the output voltage of the synchronous motor. .

Moreover, in some embodiments, feedforward control unit 130 includes a proportional controller 132 and a reference model 134. Similar to the operation of the proportional controller 122 in the voltage control unit 120, the proportional controller 132 can also be used to receive the DC bus voltage Vbus from the system DC bus and output the voltage standard bit Vt.

The reference model 134 in the feedforward control unit 130 is a motor model obtained from the magnetic interlinking parameters of the synchronous machine. Thereby, the feedforward control unit 130 can calculate the field weakening current feedforward term Id _ffd by the reference model 134 according to the electrical frequency ω _{r of the} synchronous motor, the voltage standard bit Vt and the current intersecting current command Iq _cmd .

Specifically, in some embodiments, the field weakening current feedforward term _Idffd can be expressed as: according to the synchronous axis voltage equation of the synchronous motor in the steady state model: Where ω _r is the electrical frequency, For the magnetic flux linkage parameters of the synchronous motor, For the maximum phase voltage, For the direct axis inductance, For the axis of inductance. In other words, given the relevant inductance parameters and magnetic flux linkage parameters of the synchronous motor, it will correspond to the maximum phase voltage. The voltage source standard bit Vt and the electric frequency ω _r and the cross-axis current command Iq _{cmd are} substituted into the reference model 134, and the corresponding field weak current feedforward term Id _ffd can be calculated. Thereby, in the present case, the field weakening control combined with the field weakening current command Id _vc output by the voltage controller 126 of the voltage control unit 120 and the weak magnetic current feedforward term Id _ffd output by the reference model 134 in the feedforward control unit 130 can be The field weakening control is more accurate, the error in steady state is reduced and the steady state characteristics of the synchronous motor system are satisfied.

In some embodiments, the current command compensation unit 140 includes an operation unit 142, a limiter unit 144, and an operation unit 146. As shown in the figure, the operation unit 142 may receive the field weakening current command Id _vc , the field weakening current feedforward term Id _ffd , and the first _direct axis current command Id _mtp output by the maximum torque current ratio control unit 110, respectively, and correspondingly The difference between the sum of the field weakening current command Id _vc and the field weakening current feedforward term Id _ffd and the first _direct axis current command Id _{mtp is calculated} to obtain a field weakening current compensation amount.

The clipping unit 144 can receive the weak magnetic current compensation amount output by the arithmetic unit 142 and limit the weak magnetic current compensation amount. Specifically, in some embodiments, when the field weakening current compensation amount is greater than zero, the field weakening current compensation amount Id _comp output by the limiting unit 144 is zero. In other words, when the field weakening current compensation amount is positive, the current command compensation unit 140 can determine that the first _direct axis current command Id _mtp output from the maximum torque current ratio control unit 110 is not required to be adjusted, and maintain the maximum torque current ratio. Output current command under control strategy. In contrast, when the field weakening current compensation amount is negative, the current command compensation unit 140 may determine that the field weakening control is required, and output the field weakening current compensation amount Id _{comp to} compensate the first straight axis current command Id _mtp to switch to the weak magnetic current. Operating area.

In this way, the arithmetic unit 146 can add the weak magnetic current compensation amount Id _comp and the first direct-axis current command Id _mtp to obtain a new second direct-axis current command Id _cmd to realize output according to the limiting unit 144. The field weak current compensation amount Id _comp corrects the original first _direct axis current command Id _mtp .

In some embodiments, the voltage command output unit 150 includes an arithmetic unit 152, a direct current controller 154, an arithmetic unit 156, and a cross current controller 158. Calculation unit 152 may calculate feedback current Id _fbk axis current Id _err error value according to the second straight axis the direct axis current command Id _cmd synchronous motor. Thereby, the direct-axis current controller 154 can output the corresponding direct-axis voltage command Vd* according to the direct-axis current error value _Iderr . Similarly, the arithmetic unit 156 can calculate the cross-axis current error value Iq _err according to the cross-axis current command Iq _cmd and the cross-axis feedback current Iq _{fbk of the} synchronous motor. Thereby, the cross-axis current controller 158 can output the corresponding cross-axis voltage command Vq* according to the cross-axis current error value Iq _err .

Please refer to Figure 3. FIG. 3 is a flow chart of a control method 300 in accordance with some embodiments of the present disclosure. Control method 300 can be used to control a synchronous machine. For convenience and clarity of description, the following control method 300 is described with reference to the embodiments shown in FIGS. 1 and 2, but it is not limited thereto, and any person skilled in the art can avoid the spirit and scope of the present invention. Inside, when you can make a variety of changes and retouching. As shown in FIG. 3, the control method 300 includes steps S310, S320, S330, S340, and S350.

First, in step S310, the first _direct- axis current command Id _mtp and the cross-axis current command Iq _{cmd are} calculated by the maximum torque-current ratio control unit 110 based on the frequency command ω _cmd and the electric frequency ω _{r of the} synchronous motor.

Next, in step S320, when the feedback output voltage V _{fbk of the} synchronous motor is greater than the voltage control level Vc, the field weakening current command Id _{vc is} output by the voltage control unit 120. In some embodiments, the DC bus voltage Vbus is received by the proportional controller 122 in the voltage control unit 120 to output the voltage control level Vc in step S320.

Next, in step S330, the field weakening current feedforward term _{Idffd is} calculated by the feedforward control unit 130 based on the electric frequency ω _{r of the} synchronous motor, the voltage standard bit Vt, and the intersecting current command Iq _cmd . In some embodiments, the DC bus voltage Vbus is received by the proportional controller 132 in the feedforward control unit 130 to output a voltage target standard bit Vt in step S330.

Specifically, in step S330, the reference model 134 is obtained according to the magnetic flux linkage parameter of the synchronous motor; and the reference model 134 is calculated according to the electrical frequency ω _{r of the} synchronous motor, the voltage standard bit Vt, and the intersecting current command Iq _cmd . _Field weakening current feedforward term Id _ffd .

Next, in step S340, when the sum of the field weakening current command Id _vc and the field weakening current feedforward term Id _ffd is smaller than the first straight axis current command Id _mtp , the current command compensation unit 140 commands the weak magnetic current Id _vc with The sum of the field weakening current feedforward terms Id _ffd adjusts the first straight axis current command Id _mtp .

Specifically, the step of adjusting the first _direct- axis current command Id _mtp by the current command compensation unit 140 includes: calculating, by the operation unit 142, the sum of the weak magnetic current command Id _vc and the weak magnetic current feedforward term Id _ffd and the first _direct- axis current The difference between the commands Id _mtp is obtained to obtain the weak magnetic current compensation amount; the limiting unit 144 limits the weak magnetic current compensation amount, and when the weak magnetic current compensation amount is greater than zero, the weakening current compensation amount Id output by the limiting unit 144 _Comp is zero; and the first straight-axis current command Id _{mtp is} corrected by the arithmetic unit 146 according to the clipped field weak current compensation amount Id _comp to output a new second straight-axis current command Id _cmd .

Finally, in step S350, the voltage command output unit 150 outputs the straight-axis voltage command Vd* and the cross-axis voltage command Vq* according to the second straight-axis current command Id _cmd and the cross-axis current command Iq _cmd , respectively, to drive the synchronous motor.

Specifically, further comprising the step S350, the direct axis Id _cmd command and the synchronous motor by the arithmetic unit 152 according to the second straight axis current Id _fbk feedback current Id _err calculating the direct axis current error value. Next, the straight-axis current command 154 outputs a straight-axis voltage command Vd* from the straight-axis current error value _Iderr . Next, the arithmetic unit 156 calculates the cross-axis current error value Iq _err based on the cross-axis current command Iq _cmd and the synchronous-axis feedback current Iq _{fbk of the} synchronous motor. Finally, the cross-axis current command 158 outputs the cross-axis voltage command Vq* based on the cross-axis current error value Iq _err .

Those skilled in the art can directly understand how this control method 300 is based on the synchronous motor control circuit 100 of the various different embodiments described above to perform such operations and functions, and thus will not be described again.

Please refer to Figure 4. FIG. 4 is a schematic diagram of a synchronous motor control circuit 100 according to other embodiments of the present invention. In FIG. 4, similar elements related to the embodiment of FIG. 1 and FIG. 2 are denoted by the same reference numerals for easy understanding, and the specific principles of similar elements have been described in detail in the previous paragraph, if not with the fourth The elements of the diagram have a cooperative relationship and are necessary to introduce them, and will not be described here.

As shown in FIG. 4, in some embodiments, the synchronous motor control circuit 100 further includes a voltage saturation adjustment unit 160 for adjusting the frequency command ω _cmd output to the maximum torque current ratio control unit 110 when the voltage is saturated. Specifically, the voltage saturation adjustment unit 160 includes a voltage saturation regulator 162 and a frequency command operation unit 164. The voltage saturation regulator 162 is configured to _perform a difference between the second direct-axis current command Id _cmd and the direct-axis feedback current Id _fbk (ie, the direct-axis current error value Id _err ), and the cross-axis current command Iq _cmd and the cross-axis back The frequency command correction term Δω is calculated by the difference between the current Iq _fbk (ie, the cross-axis current error value Iq _err ). The frequency command operation unit 164 is electrically coupled to the voltage saturation regulator 162 for adjusting the original frequency command ω _temp according to the frequency command correction term Δω to output a new frequency command ω _cmd to the maximum torque current ratio control unit 110.

In this way, during the transient process in which the output voltage is saturated, the synchronous motor control circuit 100 can instantly adjust the frequency command ω _cmd through the voltage saturation adjusting unit 160 to slow down the saturation phenomenon. Thereby, when the synchronous motor control circuit 100 controls the synchronous motor to switch to the field weakening operation region, the stability of the transient process can be effectively improved, and the speed controller 114 and the direct-axis current controller 154 and the cross-axis current controller 158 are controlled. Normal operation of the device to avoid malfunctions such as stall or overcurrent.

In addition, as shown in FIG. 4, in some embodiments, the synchronous motor control circuit 100 further includes a limiting unit 170 and a limiting unit 180. The limiting unit 170 is coupled between the current command compensation unit 140 and the voltage command output unit 150. The limiting unit 180 is coupled between the maximum torque current ratio control unit 110 and the voltage command output unit 150. In the embodiment illustrated in FIG. 4, the corrected direct-axis current command Id _temp and the maximum torque-current ratio control unit 110 output by the current command compensation unit 140 are compared with the embodiment shown in FIG. The output cross-axis current command Iq _temp will be clipped by the limiter unit 170 and the limiter unit 180, respectively, to prevent the voltage command output unit 150 from receiving an excessive current command, resulting in an abnormal operation or an accident. The limiting unit 170 and the limiting unit 180 respectively limit the direct-axis current command Id _temp and the intersecting current command Iq _temp , and respectively output a new second direct-axis current command Id _cmd and an intersecting current command Iq _cmd to the voltage. The command output unit 150 is provided for subsequent control and calculation.

Please refer to Figure 5 together. FIG. 5 is a flow chart of a control method 500 in accordance with some embodiments of the present disclosure. For convenience and clarity of description, the following control method 500 is described in conjunction with the embodiment shown in FIG. 4, but it is not limited thereto, and any person skilled in the art can, without departing from the spirit and scope of the present invention, Make a variety of changes and retouching. As shown in FIG. 5, in comparison with the control method 300 in FIG. 3, the control method 500 shown in FIG. 5 further includes steps S510 and S520.

First, at step S510, the saturation voltage adjusting unit 160 from the voltage regulator 162 saturation value Id _err and quadrature axis current value Iq _err error correction term calculating frequency command in accordance with the direct axis current error Δω. Specifically, the straight-axis current error value Id _err is the difference between the second straight-axis current command Id _cmd and the direct-axis feedback current Id _fbk , and the cross-axis current error value Iq _err is the cross-axis current command Id _cmd and the cross-axis feedback The difference between the currents Id _fbk .

Next, in step S520, the frequency command operation unit 164 in the voltage saturation adjustment unit 160 adjusts the frequency command ω _temp according to the frequency command correction term Δω to output a new frequency command ω _cmd to the maximum torque current ratio control unit 110.

The remaining steps S310-S350 in the control method 500 are similar to those in the embodiment shown in FIG. 3, and have been described in detail in the previous paragraphs, and thus will not be described again. Those skilled in the art can directly understand how this control method 500 is based on the synchronous motor control circuit 100 of the various different embodiments described above to perform such operations and functions, and thus will not be described again.

While the methods disclosed are shown and described herein as a series of steps or events, it is understood that the order of the steps or events shown should not be construed as limiting. For example, some of the steps may occur in a different order and/or concurrently with other steps or events other than those illustrated or/or described herein. In addition, not all of the steps shown herein are required in the practice of one or more aspects or embodiments described herein. Moreover, one or more steps herein may also be performed in one or more separate steps and/or stages.

In summary, by applying various embodiments of the present invention, the synchronous motor control circuit of the present invention provides a weak magnetic current by combining the voltage control unit and the feedforward control of the motor reference model, and can simultaneously take into account the fast response and stable operation of the controller. In addition, in some embodiments, by adding a voltage saturation adjustment unit, the frequency command can be instantly adjusted to improve the saturation of the voltage or current, and the saturation phenomenon of the voltage or current can be improved in the case of the variation of the motor orthogonal axis inductance, the change of the magnetic flux or the sudden change of the load. Transient stability.

It should be noted that the features and circuits in the various drawings, embodiments, and embodiments of the present disclosure may be combined with each other without conflict. The circuits illustrated in the drawings are for illustrative purposes only and are simplified for simplicity and ease of understanding and are not intended to limit the present invention.

In addition, each of the circuit units in the above embodiments may be implemented by various types of digital or analog circuits, or may be implemented by different integrated circuit chips. Each component can also be integrated into a single digital control chip, or by a microcontroller (MCU), a Complex Programmable Logic Device (CPLD), or a field programmable gate array (Field-programmable). The gate array (FPGA) or various processors or other integrated circuit chips are implemented in different manners, and the above is merely an example, and the disclosure is not limited thereto.

The present disclosure has been disclosed in the above embodiments, and is not intended to limit the disclosure, and the present disclosure may be variously modified and retouched without departing from the spirit and scope of the present disclosure. The scope of protection of the content is subject to the definition of the scope of the patent application.

100‧‧‧Synchronous motor control circuit
110‧‧‧Maximum torque current ratio control unit
112‧‧‧ arithmetic unit
114‧‧‧Speed controller
116‧‧‧Direct axis current command calculation unit
118‧‧‧Axis current command calculation unit
120‧‧‧Voltage control unit
122‧‧‧Proportional controller
124‧‧‧ arithmetic unit
126‧‧‧Voltage controller
130‧‧‧Feed-for-control unit
132‧‧‧Proportional controller
134‧‧‧ reference model
140‧‧‧current command compensation unit
142, 146‧‧‧ arithmetic unit
144‧‧‧Limiting unit
150‧‧‧Voltage command output unit
152, 156‧‧‧ arithmetic unit
154‧‧‧Direct shaft current controller
158‧‧‧cross shaft current controller
160‧‧‧Voltage saturation adjustment unit
162‧‧‧Voltage saturation regulator
164‧‧‧frequency command arithmetic unit
170, 180‧‧‧ Limiting unit
300, 500‧‧‧ control methods
S310～S350, S510, S520‧‧‧ steps
Vd*, Vq*‧‧‧ voltage commands
Vbus‧‧‧ DC bus voltage
Vc‧‧‧ voltage control level
Vt‧‧‧ voltage standard position
V _fbk ‧‧‧reported output voltage
V _err ‧‧‧ voltage error value
Id _mtp , Id _temp , Id _cmd , Iq _temp , Iq _{cmd ‧ ‧} current command
Id _fbk , Iq _fbk ‧‧‧Responsive current
Id _err , Iq _err ‧‧‧ current error value
Id _vc ‧‧‧field weak current command
Id _{ffd ‧‧‧field} weak current feedforward
Id _comp ‧‧‧ weak magnetic current compensation
T _cmd ‧‧‧Torque command ω _temp , ω _cmd ‧‧‧frequency command ω _err ‧‧‧frequency error value Δω‧‧‧frequency command correction term ω _r ‧‧‧electric frequency

FIG. 1 is a schematic diagram of a synchronous motor control circuit according to some embodiments of the present disclosure. FIG. 2 is a schematic diagram of a synchronous motor control circuit according to some embodiments of the present invention. FIG. 3 is a flow chart of a control method according to some embodiments of the present disclosure. FIG. 4 is a schematic diagram of a synchronous motor control circuit according to other embodiments of the present invention. FIG. 5 is a flow chart of a control method according to some embodiments of the present disclosure.

300‧‧‧Control method

S310~S350‧‧‧Steps

Claims (10)

A control method for controlling a synchronous motor, wherein the control method comprises: calculating, by a maximum torque current ratio control unit, a first direct current command and an axis of intersection with an electrical frequency of the synchronous motor according to a frequency command a current command; when a feedback output voltage of the synchronous motor is greater than a voltage control level, a voltage weakening current command is output by a voltage control unit; and a feedforward control unit is based on the electrical frequency and a voltage standard level. And the quadrature current command calculates a field weakening current feed term; when the sum of the field weakening current command and the field weakening current feed term is less than the first straight axis current command, the weak magnetic current command and the weak a sum of the magnetic current feedforward terms to adjust the first direct axis current command to output a second direct axis current command; and a voltage command output unit respectively output the straight axis according to the second straight axis current command and the intersecting current command The voltage command is commanded with a cross-axis voltage to control the synchronous motor. The control method of claim 1, wherein calculating the field weakening current feedforward by the feedforward control unit comprises: obtaining a reference model according to a magnetic flux linkage parameter of the synchronous motor; and according to the electrical reference by the reference model The frequency, the voltage standard bit, and the quadrature current command calculate the field weakening current feed term. The control method of claim 1, further comprising: calculating, by a voltage saturation adjusting unit, a frequency command correction term according to the constant current error value and an quadrature current error value, wherein the direct axis current error value is the second a difference between the direct axis current command and the constant axis feedback current, the offset current error value is a difference between the cross shaft current command and a quadrature axis feedback current; and the voltage saturation adjustment unit adjusts the correction command according to the frequency command Frequency command. The control method of claim 1, further comprising: calculating, by a first computing unit, a difference between the weak magnetic current command and the weak magnetic current feedforward term and the first straight axis current command to obtain a field weakening Current compensation amount; limiting the field weakening current compensation amount by a limiting unit, wherein when the field weakening current compensation amount is greater than zero, the weakening current compensation amount output by the limiting unit is zero; The second operation unit corrects the first direct axis current command according to the limited field weak current compensation amount to output the second direct axis current command. The control method of claim 1, wherein the outputting the direct-axis voltage command and the cross-axis voltage command by the voltage command output unit comprises: a third arithmetic unit according to the second straight-axis current command and the synchronous motor The continuous axis current error value is calculated by the constant axis feedback current; the straight axis current controller of the voltage command output unit outputs the direct axis voltage command according to the straight axis current error value; and the fourth arithmetic unit commands according to the intersecting current Calculating an axis current error value with an axis feedback current of the synchronous motor; and outputting the axis voltage command according to the axis current error value by an AC axis current controller of the voltage command output unit. The control method of claim 1, further comprising: receiving a DC bus voltage from a first proportional controller of the voltage control unit to output the voltage control level; and a first one of the feedforward control units The two proportional controller receives the DC bus voltage to output the voltage standard bit. A synchronous motor control circuit comprising: a maximum torque current ratio control unit for calculating a first direct current command and an offset current command based on a frequency command and an electrical frequency of a synchronous motor; And outputting a weak magnetic current command according to a feedback output voltage of the synchronous motor and a voltage control level; a feedforward control unit for determining the electrical frequency, a voltage standard bit, and the cross current Commanding a weak current current feedforward term; a current command compensation unit electrically coupled to the maximum torque current ratio control unit, the voltage control unit, and the feedforward control unit for commanding the weak magnetic current according to the The field weakening current feedforward term adjusts the first direct axis current command to output a second direct axis current command; and a voltage command output unit electrically coupled to the current command compensation unit and the maximum torque current ratio control a unit for respectively outputting a constant axis voltage command and a quadrature axis voltage command according to the second straight axis current command and the intersecting axis current command to control the Step motor. The synchronous motor control circuit of claim 7, further comprising a voltage saturation adjustment unit, the voltage saturation adjustment unit comprising: a voltage saturation regulator for returning current according to the second direct current command and the constant axis a difference, and a difference between the cross-axis current command and a quadrature feedback current, a frequency command correction term; and a frequency command operation unit for adjusting the frequency command according to the frequency command correction term. The synchronous motor control circuit of claim 7, wherein the current command compensation unit comprises: a first operation unit configured to calculate a sum of the field weak current command and the field weak current feedforward term and the first straight axis The difference between the current commands to obtain a weak magnetic current compensation amount; a limiting unit for limiting the weak magnetic current compensation amount, and when the weak magnetic current compensation amount is greater than zero, the output of the limiting unit is weak The magnetic current compensation amount is zero; and a second operation unit is configured to correct the first direct axis current command output by the maximum torque current ratio control unit according to the weak magnetic current compensation amount output by the limiting unit to output the Second straight axis current command. The synchronous motor control circuit according to claim 7, wherein the feedforward control unit comprises: obtaining a reference model according to a magnetic interlinking parameter of the synchronous motor, wherein the feedforward control unit calculates the weak magnetic field by using the reference model Current feed forward term.