阅读说明：本技术 马达驱动电路与马达驱动方法 (Motor driving circuit and motor driving method ) 是由 蔡明融 于 2018-07-24 设计创作，主要内容包括：本发明公开了马达驱动电路与马达驱动方法。马达驱动电路包括驱动电压产生电路、转速命令侦测电路、校正电路与乘法器。校正电路连接于转速命令侦测电路,且乘法器连接于驱动电压产生电路与校正电路。马达驱动方法包括：透过驱动电压产生电路,提供预设驱动电压；透过转速命令侦测电路,侦测由系统端提供的工作周期信号；透过校正电路,根据工作周期信号产生调整信号；以及透过乘法器,将预设驱动电压与调整信号相乘,以产生驱动电压,使得马达的线圈电流的波形为弦波。于本发明中,调整信号代表在特定转速命令下预设驱动电压须被调整的比例。(The invention discloses a motor driving circuit and a motor driving method. The motor driving circuit comprises a driving voltage generating circuit, a rotating speed command detecting circuit, a correcting circuit and a multiplier. The correction circuit is connected to the rotation speed command detection circuit, and the multiplier is connected to the driving voltage generation circuit and the correction circuit. The motor driving method includes: providing a preset driving voltage through a driving voltage generating circuit; detecting a duty cycle signal provided by a system terminal through a rotation speed command detection circuit; generating an adjustment signal according to the duty cycle signal through a correction circuit; and multiplying the preset driving voltage by the adjusting signal through a multiplier to generate the driving voltage, so that the waveform of the coil current of the motor is a sine wave. In the present invention, the adjustment signal represents a ratio of the preset driving voltage to be adjusted under the specific rotation speed command.)

1. A motor driving circuit for providing a driving voltage to drive a motor, comprising:

a driving voltage generating circuit for providing a predetermined driving voltage;

a rotation speed command detection circuit for detecting a duty cycle signal provided by a system end to generate a rotation speed command message;

the correcting circuit is connected with the rotating speed command detecting circuit and used for generating an adjusting signal according to the rotating speed command information; and

a multiplier, connected to the driving voltage generating circuit and the correcting circuit, for multiplying the preset driving voltage by the adjusting signal to generate the driving voltage, so that the waveform of the coil current of the motor is a sine wave;

wherein the adjustment signal represents a ratio at which the predetermined driving voltage is adjusted under a specific rotation speed command.

2. The motor driving circuit as claimed in claim 1, wherein the waveform of the adjustment signal is determined by a plurality of master nodes, the calibration circuit stores a plurality of numerical value graphs correspondingly, and each of the numerical value graphs records a numerical value of the corresponding master node under different speed commands.

3. The motor driving circuit of claim 2, wherein the speed command information indicates a speed command of the motor, and the calibration circuit determines the values of the master nodes using the value graphs to generate the adjustment signal according to the speed command of the motor.

4. The motor driving circuit of claim 3, wherein the correction circuit determines the value of any sub-node between the plurality of main nodes by interpolation when generating the adjustment signal.

5. The motor drive circuit according to claim 4, wherein a resolution of a waveform of the adjustment signal is equal to a resolution of a waveform of the preset drive voltage.

6. A motor driving method for controlling a motor driving circuit to provide a driving voltage to drive a motor, wherein the motor driving circuit includes a driving voltage generating circuit, a rotation speed command detecting circuit, a correcting circuit and a multiplier, the correcting circuit is connected to the rotation speed command detecting circuit, the multiplier is connected to the driving voltage generating circuit and the correcting circuit, the motor driving method comprising:

providing a preset driving voltage through the driving voltage generating circuit;

detecting a duty cycle signal provided by a system end through the rotating speed command detecting circuit so as to generate rotating speed command information;

generating an adjusting signal according to the duty cycle signal through the correcting circuit; and

multiplying the preset driving voltage by the adjusting signal through the multiplier to generate the driving voltage, so that the waveform of the coil current of the motor is a sine wave;

wherein the adjustment signal represents a ratio at which the predetermined driving voltage is adjusted under a specific rotation speed command.

7. The motor driving method as claimed in claim 6, wherein the calibration circuit stores a plurality of value profiles, the waveform of the adjustment signal is determined by a plurality of master nodes, and the plurality of value profiles respectively record a value of the master node under different rotation speed commands.

8. The motor driving method according to claim 7, wherein the rotation speed command information indicates a rotation speed command of the motor, and the values of the plurality of master nodes are determined from the plurality of value profiles according to the rotation speed command of the motor.

9. The motor driving method of claim 8, wherein the value of any sub-node between the main nodes is determined by interpolation when the adjustment signal is generated.

10. The motor driving method according to claim 9, wherein a resolution of a waveform of the adjustment signal is equal to a resolution of a waveform of the preset driving voltage.

Technical Field

The present invention relates to a motor driving circuit and a motor driving method, and more particularly, to a motor driving circuit and a motor driving method capable of making a waveform of a coil current of a motor approach an ideal sine wave at different rotation speeds.

Background

According to different magnetizing shapes of the magnetic strips of the rotor of the motor and the waveform of counter electromotive force generated by the movement of the coil of the motor in a magnetic field, the current of the coil of some motors is suitable for square waves, the current of some motors is suitable for sine waves, and the current of some motors needs to be additionally switched in combination with the inductance characteristic of the coil.

Generally, if the motor is driven by a sine wave voltage, the lateral force of the motor can be greatly reduced due to smooth transmission of the driving force, so as to achieve the effect of reducing the vibration noise. In practice, for a motor suitable for a coil current of a sine wave, a circuit designer often adjusts a waveform of a three-phase driving voltage supplied to the motor from the sine wave to a double-arched waveform.

However, due to the influence of other factors, such as: the non-ideal characteristics of the circuit components, even if the waveform of the three-phase driving voltage supplied to the motor is adjusted from a sine wave to a double-arch waveform, cannot make the coil current of the motor present a more ideal sine wave waveform, which is particularly obvious when the motor speed is low.

Disclosure of Invention

The invention provides a motor driving circuit and a motor driving method in order to enable coil current of a motor to present ideal sine wave waveform.

The motor driving circuit provided by the invention comprises a driving voltage generating circuit, a rotating speed command detecting circuit, a correcting circuit and a multiplier. The correction circuit is connected to the rotation speed command detection circuit, and the multiplier is connected to the driving voltage generation circuit and the correction circuit. The driving voltage generating circuit provides a preset driving voltage. The rotation speed command detection circuit detects the working period signal provided by the system end and generates rotation speed command information according to the working period signal. The correction circuit generates an adjustment signal according to the rotation speed command information. The multiplier multiplies a preset driving voltage by the adjustment signal to generate a driving voltage so that a waveform of a coil current of the motor is a sine wave. In the motor driving circuit provided by the invention, the adjusting signal represents the proportion of the preset driving voltage which needs to be adjusted under a specific rotating speed command.

In an embodiment of the motor driving circuit provided by the present invention, the waveform of the adjustment signal is determined by a plurality of master nodes. Meanwhile, the correction circuit correspondingly stores a plurality of numerical value graphs, and each numerical value graph records a numerical value of the corresponding main node under different rotating speed commands.

The motor driving method provided by the invention is used for controlling the motor driving circuit provided by the invention to generate driving voltage to drive a motor. Therefore, the motor driving method generally includes the steps of: providing a preset driving voltage; detecting a working period signal provided by a system end, and generating rotating speed command information according to the working period signal; generating an adjusting signal according to the rotating speed command information; and multiplying the preset driving voltage by the adjusting signal to generate the driving voltage, so that the waveform of the coil current of the motor is a sine wave. Similarly, in the motor driving method provided by the present invention, the adjustment signal represents a ratio of the preset driving voltage to be adjusted under a specific rotation speed command.

In summary, the main feature of the motor driving circuit and the motor driving method provided by the present invention is that the three-phase driving voltage provided to the motor can be automatically adjusted at different rotation speeds, so that the coil current of the motor can present a more ideal sine wave waveform even under the influence of other factors (such as non-ideal characteristics of circuit components).

For a better understanding of the nature and technical content of the present invention, reference should be made to the following detailed description of the invention, taken in conjunction with the accompanying drawings, which are included to illustrate, but are not to be construed as limiting the scope of the invention.

Drawings

Fig. 1 is a block diagram illustrating a motor driving circuit according to an exemplary embodiment of the invention.

Fig. 2A is a schematic diagram of a preset driving voltage according to an exemplary embodiment of the invention.

Fig. 2B is a schematic diagram of an adjustment signal according to an exemplary embodiment of the invention.

Fig. 3A and 3B are diagrams illustrating a numerical curve according to an exemplary embodiment of the invention.

Fig. 4A and 4B are a waveform simulation result of a coil current of a motor when a general motor driving circuit operates, and a waveform simulation result of a coil current of a motor when a motor driving circuit according to an exemplary embodiment of the present invention operates, respectively.

Fig. 5 is a flowchart illustrating a motor driving method according to an exemplary embodiment of the invention.

Detailed Description

Various exemplary embodiments will be described more fully hereinafter with reference to the accompanying drawings, in which some exemplary embodiments are shown. The inventive concept may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. Like numbers refer to like elements throughout.

It will be understood that, although the terms first, second, third, etc. may be used herein to describe various components or elements, these components or elements should not be limited by these terms. These terms are only used to distinguish one element or component from another element or component. Thus, a first component or element discussed below could be termed a second component or element without departing from the teachings of the present invention.

[ one embodiment of Motor drive Circuit ]

Referring to fig. 1, fig. 1 is a block diagram illustrating a motor driving circuit according to an exemplary embodiment of the invention. As shown in fig. 1, the motor driving circuit of the present embodiment includes a driving voltage generating circuit 10, a rotation speed command detecting circuit 20, a correcting circuit 30 and a multiplier 40. The RPM detecting circuit 20 is connected to the calibration circuit 30, and the multiplier 40 is connected to the driving voltage generating circuit 10 and the calibration circuit 30.

The driving voltage generating circuit 10 is used for providing a preset driving voltage Vdet to the motor. The speed command detection circuit 20 is used for detecting a duty cycle signal PWM provided by a system terminal SYS. Since the duty cycle signal PWM is used to determine the rotation speed command of the motor, the rotation speed command detecting circuit 20 can obtain the rotation speed command of the motor determined by the system terminal SYS according to the duty cycle signal PWM, so that the rotation speed command detecting circuit 20 can generate the rotation speed command information Iduty representing the rotation speed command of the motor accordingly. The main operation principle of the motor driving circuit provided in this embodiment is that after receiving the rotation speed command information Iduty representing the rotation speed command of the motor from the rotation speed command detecting circuit 20, the calibration circuit 30 generates the adjustment signal R according to the rotation speed command information Iduty. Then, the multiplier 40 multiplies the preset driving voltage Vdet by the adjustment signal R to generate a driving voltage to be supplied to the motor.

The adjusting signal R generated by the calibration circuit 30 according to the rotation speed command information Iduty represents a ratio of the preset driving voltage Vdet to be adjusted under a specific rotation speed command of the motor. That is, the preset driving voltage Vdet is adjusted by being multiplied by the adjustment signal R. It is noted that, in the present embodiment, the adjusted preset driving voltage Vdet is provided to the motor, so that the waveform of the coil current of the motor approaches to an ideal sine wave.

In the following description, details of the calibration circuit 30 for generating the adjustment signal R according to the rotation speed command information Iduty will be further described.

Referring to fig. 2A, fig. 2A is a schematic diagram illustrating a preset driving voltage according to an exemplary embodiment of the invention. As shown in fig. 2A, the preset drive voltage Vdet generated by the drive voltage generation circuit 10 is designed to assume a double-arched waveform in consideration of the equivalent circuit characteristics of the coils of the motor. For convenience of illustration, the resolution of the waveform of the preset driving voltage Vdet in fig. 2A is designed to be 8 bits (i.e., the waveform of the preset driving voltage Vdet can be depicted by connecting 256 points), but the invention is not limited thereto.

Referring to fig. 2B, fig. 2B is a schematic diagram illustrating an adjustment signal according to an exemplary embodiment of the invention. In the present embodiment, the waveform of the adjustment signal R is determined by a plurality of main nodes N1-N12, and each of the main nodes N1-N12 corresponds to one of the points in the waveform of the preset driving voltage Vdet in fig. 2A. For example, in fig. 2A and 2B, the main node N3 of the waveform of the adjustment signal R corresponds to a point a in the waveform of the preset driving voltage Vdet, and the main node N6 of the waveform of the adjustment signal R corresponds to a point B in the waveform of the preset driving voltage Vdet.

The adjustment signal R shown in fig. 2B represents the ratio of the preset driving voltage to be adjusted at a specific rotation speed command of the motor. In order to make the coil current of the motor present a more ideal sine wave waveform, the preset driving voltage Vdet supplied to the motor is adjusted. Please refer to fig. 2A and fig. 2B for understanding. Assuming that the initial value of each of the main nodes N1-N12 in the waveform of the adjustment signal R is 50%, when the time point of the coil current of the motor, which causes the waveform to deviate from the ideal sine wave, corresponds to the point a in the waveform of the preset drive voltage Vdet, the adjustment signal R (i.e., the proportion of the preset drive voltage Vdet that has to be adjusted) is increased (as shown in fig. 2B, the value of the main node N3 is pulled up from 50% to 100%), so that the preset drive voltage Vdet supplied to the motor is equivalently increased by multiplying the adjustment signal R (as shown in fig. 2A, the point a in the waveform of the preset drive voltage Vdet is pulled up to the point a'). Conversely, when the time point at which the coil current of the motor is too high to deviate the waveform from the ideal sine wave corresponds to the point B in the waveform of the preset driving voltage Vdet, the adjustment signal R (i.e., the proportion of the preset driving voltage Vdet that has to be adjusted) is lowered (as shown in fig. 2B, the value of the main node N6 is pulled up from 50% to 30%), so that the preset driving voltage Vdet supplied to the motor is equivalently lowered by multiplying the adjustment signal R (as shown in fig. 2A, the point B in the waveform of the preset driving voltage Vdet is pulled up to the point B').

Referring to fig. 3A and 3B, fig. 3A is a schematic diagram illustrating a numerical curve according to an exemplary embodiment of the invention.

In the present embodiment, the calibration circuit 30 stores a plurality of numerical graphs CUR1 and CUR2 as shown in fig. 3A and 3B. In more detail, each of the value graphs corresponds to a master node in the waveform of the adjustment signal R. In the above example, assuming that the waveform of the adjustment signal R is determined by 12 master nodes N1-N12, the correction circuit 30 stores 12 numerical value graphs, such as the numerical value graphs CUR1 and CUR2 shown in fig. 3A and 3B, but the invention is not limited thereto, and the number of master nodes in the waveform of the adjustment signal R (which is equal to the number of numerical value graphs stored in the correction circuit 30) is not limited.

In fig. 3A, the numerical graph CUR1 corresponds to the master node N1 in the waveform of the adjustment signal R, and the numerical graph CUR2 corresponds to the master node N2 in the waveform of the adjustment signal R. Furthermore, each numerical graph, for example: the numerical graphs CUR1, CUR2 record the corresponding master nodes, such as: the master nodes N1, N2 are set to values at different rotation speed commands D of the motor. For example, the numerical graph CUR1 in fig. 3A corresponds to the master node N1 in the waveform of the adjustment signal R in fig. 2B, and the numerical graph CUR1 records the values of the master node N1 set at different rotation speed commands D of the motor, such as: when the duty cycle of the motor is 10%, 50%, 90%, etc.

The calibration circuit 30 can obtain the rotation speed command D of the motor according to the rotation speed command information Iduty generated by the rotation speed command detection circuit 20. Therefore, according to the rotation speed command D of the motor, the calibration circuit can obtain the values of the master nodes by using the value graphs to generate the adjustment signal R. For example, when the duty cycle of the motor is 50%, the calibration circuit can know that the master node N1 is set to 100% when the duty cycle of the motor is 50% through the numerical graph CUR1, and know that the master node N2 is set to 50% when the duty cycle of the motor is 50% through the numerical graph CUR 2. After the values set for the master nodes in the waveform of the adjustment signal R under a certain rotation speed command D of the motor are known, the correction circuit 30 can generate the adjustment signal R under a certain rotation speed command D of the motor according to the values.

It should be noted that, in the embodiment, when designing the value graph of each master node, for the convenience of practical operation, the initial value of each master node under different speed commands D may be set to 50%, and then the value of each master node under different speed commands D is adjusted from 50% up or down according to the coil current of the motor under different speed commands D. Further, as seen from the numerical graph CUR1, since the value of the main node N1 is adjusted upward from 50% to 100% when the duty cycle of the motor is 50% (i.e., the point C of the numerical graph CUR1 in fig. 3A is adjusted upward to the point C'), it indicates that the value of the point corresponding to the main node N1 in the waveform of the preset driving voltage is doubled when the duty cycle of the motor is 50%, so that the coil current of the motor is increased; in the case of the numerical graph CUR2, since the main node N2 maintains the value at 50% of the initial setting when the duty cycle of the motor is 50% (i.e., the point E of the numerical graph CUR2 in fig. 3B is maintained at the same position), it indicates that the value at the point corresponding to the main node N2 in the waveform of the preset driving voltage does not need to be adjusted up or down when the duty cycle of the motor is 50%. However, the present invention is not limited herein to the initial values of the respective master nodes when designing the numerical value graph.

It should be noted that, in the present embodiment, the resolution of the waveform of the adjustment signal R is equal to the resolution of the waveform of the preset driving voltage. Assuming that the resolution of the waveform of the preset driving voltage in fig. 2A is designed to be 8bit (i.e., the waveform of the preset driving voltage can be depicted by connecting 256 points), the resolution of the waveform of the adjustment signal R can also be designed to be 8bit (i.e., the waveform of the adjustment signal R can be depicted by connecting 256 points). That is, if the resolution of the waveform of the predetermined driving voltage in fig. 2A and 2B is designed to be 8 bits, the calibration circuit 30 is designed to generate the adjustment signal R according to 256 points. By way of example, the 256 points include 12 master nodes N1-N12 and 244 child nodes between master nodes N1-N12. The calibration circuit 30 calculates the values of the 244 child nodes by interpolation when generating the adjustment signal R according to the values set by the respective master nodes. After finding the values of the master nodes N1-N12 according to the value graphs CUR1-CUR12 and calculating the values of the 244 child nodes between the master nodes N1-N12 by interpolation, the calibration circuit 30 generates the calibration signal R according to the values of the master nodes N1-N12 and the values of all the child nodes.

It should be noted that, in practice, the effect of adjusting the preset driving voltage and further adjusting the coil current of the motor can also be achieved by directly increasing or decreasing the values of each point in the waveform of the preset driving voltage through a preset lookup table. However, in addition to requiring a large storage device to store a considerable amount of lookup tables, as mentioned above, the waveform of the preset driving voltage provided by the driving voltage generating circuit 10 is a non-linear double-arch shape, and if the value of each point in the waveform of the preset driving voltage is directly adjusted up or down, the original non-linear waveform of the preset driving voltage will be destroyed. Therefore, in the present embodiment, instead of the above, the multiplier 40 multiplies the preset driving voltage by the adjustment signal R to adjust the preset driving voltage. Since the values of the points in the waveform of the adjustment signal R are a ratio, multiplying the values of the points in the waveform of the preset driving voltage by the ratio does not destroy the original nonlinear waveform of the preset driving voltage. In short, the motor driving circuit provided in the present embodiment adjusts the preset driving voltage by multiplying the preset driving voltage by the adjustment signal R by the multiplier 40, so as to maintain the nonlinearity of the preset driving voltage.

Referring to fig. 4A and 4B, fig. 4A and 4B are respectively a waveform simulation result of a coil current of a motor when a general motor driving circuit operates, and a waveform simulation result of a coil current of a motor when a motor driving circuit operates according to an exemplary embodiment of the invention.

As can be seen from fig. 4A, when the motor driving circuit is operated, if the motor is driven by the sine wave voltage, even if the motor is driven by the driving voltage with the waveform adjusted from the sine wave to the double arch shape, the influence of other factors, such as: the non-ideal characteristics of the circuit components do not enable the coil current I of the motor to present a more ideal sine wave waveform. However, in the present embodiment, the calibration circuit 30 provides different adjustment signals R to adjust the predetermined driving voltage Vdet according to different rotation speed commands of the motor. In the case that the coil current I of the motor is low and the waveform deviates from the ideal sine wave, the adjustment signal R generated by the correction circuit 30 will increase the preset driving voltage Vdet provided to the motor. On the other hand, in the case that the coil current I of the motor is too high to make the waveform deviate from the ideal sine wave, the adjustment signal R generated by the correction circuit 30 will reduce the preset driving voltage Vdet provided to the motor. Therefore, as can be seen from fig. 4B, when the motor driving circuit provided in the present embodiment operates, although the influence of the above-mentioned other factors still exists, the coil current I of the motor can present a more ideal sine wave waveform through the adjustment signal R generated by the correction circuit 30.

[ one embodiment of a Motor drive method ]

Fig. 5 is a flowchart illustrating a motor driving method according to an exemplary embodiment of the invention.

As shown in fig. 5, the motor driving method provided in this embodiment includes the following steps: providing a preset driving voltage (step S510); detecting a duty cycle signal provided by the system end to generate a rotation speed command message (step S520); generating an adjustment signal according to the duty cycle signal (step S530); and multiplying the preset driving voltage by the adjustment signal to generate a driving voltage such that the waveform of the coil current of the motor is a sine wave (step S540).

The motor driving method provided by the present embodiment can be implemented by the motor driving circuit shown in fig. 1. Referring to fig. 1 and fig. 5, in step S510, the preset driving voltage is provided by the driving voltage generating circuit 10, and in step S520, the rotation speed command detecting circuit 20 detects the duty cycle signal PWM provided by the system terminal SYS, so as to generate the rotation speed command information Iduty. Since the duty cycle signal PWM is used to determine the rotation speed command of the motor, the rotation speed command detecting circuit 20 can obtain the rotation speed command of the motor determined by the system terminal SYS according to the duty cycle signal PWM, so that the rotation speed command detecting circuit 20 can generate the rotation speed command information Iduty representing the rotation speed command of the motor accordingly. Next, in step S530, the calibration circuit 30 generates the adjustment signal R according to the rotation speed command information Iduty generated by the rotation speed command detection circuit 20. Finally, in step S540, the multiplier 40 multiplies the preset driving voltage Vdet by the adjustment signal R to generate the driving voltage (i.e., the preset driving voltage Vdet — the adjustment signal R).

As can be seen from the above description, in step S530, the adjustment signal R generated by the calibration circuit 30 according to the rotation speed command information Iduty represents the ratio of the preset driving voltage Vdet to be adjusted under a specific rotation speed command of the motor. It is noted that the driving voltage Vdet generated in step S540 is generated by adjusting the preset driving voltage Vdet through the adjustment signal R generated by the correction circuit 30, and the waveform of the coil current of the motor approaches to the ideal sine wave after the driving voltage Vdet is provided to the motor.

Therefore, the motor driving method provided by the present embodiment can control the motor driving circuit provided by the foregoing embodiment to provide the driving voltage to drive a motor, so that the waveform of the coil current of the motor can approach to an ideal sine wave. It should be noted that, since the motor driving method provided in the present embodiment can be implemented by the motor driving circuit shown in fig. 1, other details of the motor driving method provided in the present embodiment can refer to the related description of the motor driving circuit provided in the foregoing embodiment, and thus, the description is not repeated here.

[ possible effects of examples ]

In summary, through the operation of the motor driving circuit and the motor driving method of the present invention, the corresponding adjustment signal can be provided for the full rotation speed of the motor, so that the coil current of the motor can present a more ideal sine wave waveform even if there is an influence of other factors (e.g., non-ideal characteristics of circuit components) under the driving of the adjusted preset driving voltage, and the vibration noise of the motor is within an ideal range.

In addition, the motor driving circuit and the motor driving method of the invention adopt the multiplier to multiply the preset driving voltage and the adjusting signal to adjust the preset driving voltage, thereby maintaining the nonlinearity of the preset driving voltage.

It should also be noted that while in the foregoing specification, the present inventive concept has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the present inventive concept as defined by the following claims.