motor controller

Abstract

A motor controller has a switching circuit, a driving circuit, a pulse width modulation circuit, and a Hall sensor. The switching circuit is coupled to a motor to drive the motor. The driving circuit generates a plurality of control signals to control the switching circuit. The pulse width modulation circuit generates a pulse width modulation signal to the driving circuit. The Hall sensor generates a Hall signal to the pulse width modulation circuit. When the motor controller operates in a start-up mode, the motor controller employs a Hall sensor driving mode. When the motor controller operates in a normal operation mode, the motor controller employs a sensorless driving mode.

Description

Technical Field

[0001] This invention relates to a motor controller, and more particularly to a motor controller applicable to a single-phase motor or a three-phase motor. The motor controller may be a fan motor controller. Background Technology

[0002] Traditionally, motor driving methods can be divided into two types. One type uses a Hall sensor to switch phases to drive the motor. The other type drives the motor without a Hall sensor. Because the placement of Hall sensors is prone to error, it is difficult to obtain the correct commutation angle in normal operation. Furthermore, when using a sensorless driving method, the driving time in startup mode is longer and the success rate is lower compared to using a Hall sensor.

[0003] Therefore, a new motor control technology is needed to solve the above problems. Summary of the Invention

[0004] In view of the aforementioned problems, the object of the present invention is to provide a motor controller applicable to a single-phase motor or a three-phase motor. This motor controller may be a fan motor controller.

[0005] This invention provides a motor controller for driving a motor. The motor controller includes a switching circuit, a drive circuit, a pulse width modulation (PWM) circuit, and a Hall sensor. The switching circuit is coupled to the motor to drive it. The switching circuit has a first terminal, a second terminal, and a third terminal, wherein the first terminal, the second terminal, and the third terminal respectively provide a first drive signal, a second drive signal, and a third drive signal to drive the motor. The drive circuit generates a plurality of control signals to control the switching circuit. The PWM circuit generates a PWM signal to the drive circuit. The PWM signal has a duty cycle. The Hall sensor generates a Hall signal to the PWM circuit.

[0006] To address the problems of existing technologies, when the motor controller operates in a startup mode, it employs a Hall sensor-driven method. When the motor controller operates in a normal operating mode, it employs a sensorless driving method. Specifically, switching the phase based on the Hall signal generated by the Hall sensor allows for smoother motor startup, with a shorter driving time and higher success rate compared to the sensorless driving method. When the motor controller completes the startup mode and enters the normal operating mode, it can obtain the correct commutation point by detecting a zero point of the back electromotive force. In this case, the motor controller employs the sensorless driving method.

[0007] According to an embodiment of the present invention, the driving process of the motor can be divided into the following four stages:

[0008] 1. In order to start the motor smoothly, the duty cycle of the pulse width modulation signal will gradually increase from 0. When the motor controller is operating in the start mode and the duty cycle is less than a positioning duty cycle, the motor controller will generate a positioning waveform based on an initial value of the Hall signal, wherein the positioning waveform may be a part of an M-shaped wave.

[0009] 2. When the motor controller operates in the start-up mode and the working cycle is greater than the positioning working cycle, the motor controller generates a series of preset waveforms at a first forced commutation time and sends them to the first drive signal, the second drive signal and the third drive signal respectively, thereby driving the motor to obtain a first commutation point.

[0010] Third, when the first commutation point occurs, the motor controller generates multiple waveforms corresponding to the first commutation point and sends them to the first drive signal, the second drive signal, and the third drive signal, respectively. Then, at a second forced commutation time, the motor controller generates a series of preset waveforms and sends them to the first drive signal, the second drive signal, and the third drive signal, thereby driving the motor to reach a second commutation point. Before the second commutation point, the motor controller operates in the start-up mode. As mentioned above, when the motor controller operates in the start-up mode, it uses the Hall sensor drive method.

[0011] Fourth, the motor controller operates in the normal operating mode after the second commutation point. As mentioned above, when the motor controller operates in the normal operating mode, it employs the sensorless drive method. When the motor controller operates in the normal operating mode and activates a floating phase to detect a back electromotive force of the floating phase, the motor controller makes the duty cycle greater than or equal to a minimum value. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of a motor controller according to an embodiment of the present invention.

[0013] Figure 2 This is a first timing diagram according to an embodiment of the present invention.

[0014] Figure 3 This is a second timing diagram according to an embodiment of the present invention.

[0015] Figure reference numerals: 10-Motor controller; 100-Switch circuit; 110-Drive circuit; 120-Pulse width modulation circuit; 130-Hall sensor; Vp-Pulse width modulation signal; Vh-Hall signal; 101-First transistor; 102-Second transistor; 103-Third transistor; 104-Fourth transistor; 105-Fifth transistor; 106-Sixth transistor; U-First terminal; V-Second terminal; W-Third terminal; VCC-Fourth terminal; GND-Fifth terminal; C1-First control signal; C2-Second control signal; C3-Third control signal; C4-Fourth control signal; C5-Fifth control signal; C6-Sixth control signal; L1-First coil; L2-Second coil; L3-Third coil; M-Motor; Su-First drive signal; Sv-Second drive signal; Sw-Third drive signal; T1-First time point; Tp1-First commutation point; Tp2-Second commutation point. Detailed Implementation

[0016] The objects, features, and advantages of the invention will become more apparent from the following description. Preferred embodiments of the invention will now be described in detail with reference to the accompanying drawings.

[0017] Figure 1This is a schematic diagram of a motor controller 10 according to an embodiment of the present invention. The motor controller 10 is used to drive a motor M, wherein the motor M has a first coil L1, a second coil L2, and a third coil L3. In other words, the motor M can be a three-phase motor, but the present invention is not limited thereto. The motor controller 10 includes a switching circuit 100, a driving circuit 110, a pulse width modulation circuit 120, and a Hall sensor 130. The switching circuit 100 includes a first transistor 101, a second transistor 102, a third transistor 103, a fourth transistor 104, a fifth transistor 105, a sixth transistor 106, a first terminal U, a second terminal V, a third terminal W, a fourth terminal VCC, and a fifth terminal GND, wherein the switching circuit 100 is coupled to the motor M to drive the motor M. The first terminal U, the second terminal V, and the third terminal W respectively provide a first driving signal Su, a second driving signal Sv, and a third driving signal Su to drive the motor M. The first transistor 101 is coupled to the fourth terminal VCC and the first terminal U, while the second transistor 102 is coupled to the first terminal U and the fifth terminal GND. The third transistor 103 is coupled to the fourth terminal VCC and the second terminal V, while the fourth transistor 104 is coupled to the second terminal V and the fifth terminal GND. The fifth transistor 105 is coupled to the fourth terminal VCC and the third terminal W, while the sixth transistor 106 is coupled to the third terminal W and the fifth terminal GND. The first transistor 101, the third transistor 103, and the sixth transistor 106 can each be a P-type metal-oxide-semiconductor transistor. The second transistor 102, the fourth transistor 104, and the sixth transistor 106 can each be an N-type metal-oxide-semiconductor transistor.

[0018] One end of the first coil L1 is coupled to the first end U. One end of the second coil L2 is coupled to the second end V. One end of the third coil L3 is coupled to the third end W. Furthermore, the other end of the first coil L1 is coupled to the other ends of the second coil L2 and the third coil L3. That is, the first coil L1, the second coil L2, and the third coil L3 are arranged in a Y-shape. The drive circuit 110 generates a first control signal C1, a second control signal C2, a third control signal C3, a fourth control signal C4, a fifth control signal C5, and a sixth control signal C6 to control the switching of the first transistor 101, the second transistor 102, the third transistor 103, the fourth transistor 104, the fifth transistor 105, and the sixth transistor 106, respectively. The pulse width modulation circuit 120 generates a pulse width modulation signal Vp to the drive circuit 110, wherein the pulse width modulation signal Vp can be used to adjust the speed of the motor M. The pulse width modulation signal Vp has a duty cycle. Hall sensor 130 is coupled to pulse width modulation circuit 120 to detect the position of a magnetic pole of motor M and generate a Hall signal Vh to pulse width modulation circuit 120 to drive motor M. Since those skilled in the art will know how to drive motor M, this will not be described in detail here.

[0019] To address the problems of existing technologies, when the motor controller 10 operates in a startup mode, it employs a Hall sensor-driven method. When the motor controller 10 operates in a normal operating mode, it employs a sensorless driving method. Specifically, switching the phase based on the Hall signal Vh generated by the Hall sensor 130 allows for a smoother startup process for the motor M, with a shorter driving time and higher success rate compared to the sensorless driving method. When the motor controller 10 completes the startup mode and enters the normal operating mode, it can obtain the correct commutation point by detecting a zero point of the back electromotive force. In this case, the motor controller 10 employs a sensorless driving method.

[0020] According to an embodiment of the present invention, the driving process of motor M can be divided into the following four stages:

[0021] 1. In order to start the motor M smoothly, the working period of the pulse width modulation signal Vp will gradually increase from 0. When the working period is less than one positioning working period, the motor controller 10 will generate different positioning waveforms according to the initial value of the Hall signal Vh. Figure 2This is a first timing diagram according to an embodiment of the present invention. The first timing diagram shows the waveforms of the first drive signal Su, the second drive signal Sv, and the third drive signal Su generated by the motor controller 10 when the initial value of the Hall signal Vh is a low level. The first time point T1 is the time point when the working cycle is equal to the positioning working cycle. Figure 3 This is a second timing diagram according to an embodiment of the present invention. The second timing diagram shows the waveforms of the first drive signal Su, the second drive signal Sv, and the third drive signal Su generated by the motor controller 10 when the initial value of the Hall signal Vh is a high level. Figure 2 and Figure 3 As shown, the positioning waveform can be a part of an M-shaped wave.

[0022] 2. When the working cycle is longer than the positioning working cycle, the motor controller 10 generates a series of preset waveforms at a first forced commutation time, which are respectively sent to the first drive signal Su, the second drive signal Sv, and the third drive signal Su, thereby driving the three-phase motor M to obtain a first commutation point Tp1, where the first commutation point Tp1 is the time point when the Hall signal Vh first undergoes a level change and Tp1>T1. Figure 2 and Figure 3 As shown, the preset waveform can be a part of an M-shaped wave.

[0023] Third, after the first commutation point Tp1 occurs, the motor controller 10 generates multiple waveforms corresponding to the first commutation point Tp1 and sends them to the first drive signal Su, the second drive signal Sv, and the third drive signal Su, respectively. Then, at a second forced commutation time, the motor controller 10 generates a series of preset waveforms and sends them to the first drive signal Su, the second drive signal Sv, and the third drive signal Su, thereby driving the three-phase motor M to obtain a second commutation point Tp2. The second commutation point Tp2 is the time point at which the Hall signal Vh undergoes its second level change, and Tp2 > Tp1. For example... Figure 2 and Figure 3 As shown, the preset waveform can be a part of an M-shaped wave. The motor controller 10 operates in start-up mode before the second commutation point Tp2. As previously mentioned, when the motor controller 10 operates in start-up mode, it uses a Hall sensor drive method.

[0024] IV. After the second commutation point Tp2, the motor controller 10 operates in normal operating mode. As mentioned earlier, when the motor controller 10 operates in normal operating mode, it employs a sensorless drive method. When the motor controller 10 activates a floating phase to detect the back electromotive force (EMF) of the floating phase, it can limit the duty cycle of the pulse width modulation (PWM) signal Vp to a minimum value to avoid the on-time interval of the PWM signal Vp being too short. Therefore, when the motor controller 10 detects the back EMF of the floating phase during the on-time interval, detection becomes easier and the success rate of detection is improved. Depending on the application, the minimum value can be set to 10%, 20%, or other appropriate values.

[0025] The motor controller 10 of the present invention can be applied to a single-phase motor or a three-phase motor. Furthermore, the motor controller 10 can be a fan motor controller.

[0026] While the invention has been described by way of example with reference to preferred embodiments, it should be understood that the invention is not limited to the embodiments provided herein. Rather, the invention is intended to cover various modifications and similar configurations that will be apparent to those skilled in the art. Therefore, the scope of the claims should be interpreted in the broadest sense to include all such modifications and similar configurations.

[0027] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made in accordance with the claims of the present invention should fall within the scope of the present invention.

Claims

1. A motor controller for driving a motor, characterized in that, The motor controller includes: A switching circuit is coupled to the motor to drive the motor; A drive circuit is used to generate multiple control signals to control the switching circuit; A pulse width modulation circuit is used to generate a pulse width modulation signal to the drive circuit; as well as A Hall sensor is used to generate a Hall signal to the pulse width modulation circuit. When the motor controller is operating in a start mode, the motor controller uses a Hall sensor drive mode. When the motor controller is operating in a normal operation mode, the motor controller uses a sensorless drive mode.

2. The motor controller as described in claim 1, characterized in that, The pulse width modulation signal has a working period. When the motor controller operates in the start-up mode and the working period is less than a positioning working period, the motor controller generates a positioning waveform based on an initial value of the Hall signal.

3. The motor controller as described in claim 2, characterized in that, The positioning waveform is part of an M-shaped wave.

4. The motor controller as described in claim 1, characterized in that, The switching circuit also includes: A first transistor is coupled to a fourth terminal and a first terminal; A second transistor is coupled to a fifth terminal and the first terminal; A third transistor is coupled to the fourth terminal and a second terminal; A fourth transistor is coupled to the fifth terminal and the second terminal; A fifth transistor, coupled to the fourth terminal and a third terminal; and A sixth transistor is coupled to the fifth terminal and the third terminal.

5. The motor controller as described in claim 1, characterized in that, The pulse width modulation signal has a working cycle. When the motor controller operates in the start-up mode and the working cycle is greater than a positioning working cycle, the motor controller generates a series of preset waveforms at a first forced commutation time and sends them to a first drive signal, a second drive signal and a third drive signal respectively, thereby driving the motor to obtain a first commutation point.

6. The motor controller as described in claim 5, characterized in that, The motor controller generates a series of preset waveforms at a second forced commutation time and sends them to the first drive signal, the second drive signal, and the third drive signal respectively, thereby driving the motor to obtain a second commutation point, which is greater than the first commutation point.

7. The motor controller as described in claim 6, characterized in that, The motor controller operates in the start-up mode before the second commutation point.

8. The motor controller as described in claim 6, characterized in that, The motor controller operates in the normal operating mode after the second commutation point.

9. The motor controller as described in claim 1, characterized in that, The pulse width modulation signal has a duty cycle. When the motor controller is operating in the normal operating mode and the motor controller activates a floating phase to detect a back electromotive force of the floating phase, the motor controller makes the duty cycle greater than or equal to a minimum value.

10. The motor controller as claimed in claim 1, characterized in that, This motor controller is applied to a single-phase motor.

11. The motor controller as claimed in claim 1, characterized in that, This motor controller is used for a three-phase motor.

12. The motor controller as claimed in claim 1, characterized in that, The motor controller is a fan motor controller.

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