motor controller

Abstract

A motor controller has a switching circuit and a control unit. The motor controller is used to drive a motor, where the motor has a coil. The switching circuit is used to provide a coil current to the coil. The control unit is used to generate a plurality of control signals to control the switching circuit. The motor controller makes a floating phase time a variable value, where the floating phase time has a stable interval and a detection interval. The motor controller makes a zero point of the coil current in the stable interval to stably detect a commutation point and avoid a noise problem. The motor controller detects a zero-crossing point of a back electromotive force in the detection interval.

Description

Technical Field

[0001] This invention relates to a motor controller, and more particularly to a motor controller capable of reliably detecting a commutation point. Background Technology

[0002] Traditionally, motor driving methods can be divided into two types. One type uses Hall sensors to switch phases to drive the motor. The other type drives the motor without a Hall sensor. Because Hall sensors are easily affected by external environmental factors, causing a decrease in sensing accuracy, and because installing Hall sensors increases the size and cost of the system, sensorless driving methods have been proposed to solve these problems.

[0003] In sensorless driving methods, the motor controller uses a fixed floating phase time to detect a commutation point. If the floating phase time is too long, it can cause noise problems. If the floating phase time is too short, the motor controller may detect an incorrect commutation point if the current in the motor coils cannot be fully discharged. Therefore, a new motor controller is needed that can reliably detect the commutation point and avoid noise problems when the power supply voltage or motor load changes. Summary of the Invention

[0004] In view of the aforementioned problems, the object of the present invention is to provide a motor controller that can reliably detect a commutation point.

[0005] According to the present invention, a motor controller is provided. The motor controller is used to drive a motor, wherein the motor may be a three-phase motor. The motor has a first coil, a second coil, and a third coil. The motor controller includes a switching circuit, a control unit, and a detection unit. The switching circuit has a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a first terminal, a second terminal, and a third terminal, wherein the switching circuit is coupled to the motor to drive the motor. 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 first transistor is coupled to the fourth terminal and the first terminal, and the second transistor is coupled to the first terminal and the fifth terminal. The third transistor is coupled to the fourth terminal and the second terminal, and the fourth transistor is coupled to the second terminal and the fifth terminal. The fifth transistor is coupled to the fourth terminal and the third terminal, and the sixth transistor is coupled to the third terminal and the fifth terminal. The system can provide a power supply voltage to the motor controller via the fourth terminal, enabling the motor controller to operate normally.

[0006] One end of the first coil is coupled to the first end. One end of the second coil is coupled to the second end. One end of the third coil is coupled to the third end. The other end of the first coil is coupled to the other end of the second coil and the other end of the third coil. That is, the first coil, the second coil, and the third coil are arranged in a Y-shape. The control unit generates a first control signal, a second control signal, a third control signal, a fourth control signal, a fifth control signal, and a sixth control signal to control the conduction of the first transistor, the second transistor, the third transistor, the fourth transistor, the fifth transistor, and the sixth transistor, respectively. A detection unit is coupled to the first end, the second end, and the third end to generate a first detection signal and a second detection signal to the control unit. The detection unit can be used to detect a current in the first coil and a back electromotive force of a floating phase. The switching circuit is used to provide the current in the first coil to the first coil.

[0007] To address the problems of existing technologies, the motor controller makes a floating phase time a variable value, wherein the floating phase time has a stable range and a detection range. The motor controller assigns the floating phase time to the first drive signal, wherein the floating phase is formed in the first coil. When the current in the first coil is 0, the detection unit changes the first detection signal from a low level to a high level. At this time, the motor controller determines whether a zero point of the current in the first coil falls within the stable range. If the zero point of the current in the first coil appears before the stable range, the motor controller makes the next floating phase time shorter than the current floating phase time to reduce noise and improve efficiency. If the zero point of the current in the first coil appears after the stable range, the motor controller makes the next floating phase time longer than the current floating phase time to stably detect a commutation point and improve the success rate of detecting the commutation point. When the zero point of the current in the first coil occurs within the stable range, the motor controller adjusts the next floating phase time to match the current floating phase time. Through this modulation mechanism, the motor controller ensures that the zero point of the current in the first coil is within the desired stable range. Then, when the detection unit detects a zero-crossing point of the back electromotive force within the detection range, the detection unit changes the second detection signal from a low level to a high level to notify the control unit to perform a commutation procedure. Therefore, when the power supply voltage or the motor load changes, the motor controller can automatically adjust the floating phase time to stably detect the commutation point and avoid noise problems. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of a motor controller according to an embodiment of the present invention.

[0009] Figure 2 This is a timing diagram of an embodiment of the present invention.

[0010] Explanation of reference numerals in the attached diagram: 10-Motor controller; 100-Switching circuit; 110-Control unit; 120-Detection unit; 101-First transistor; 102-Second transistor; 103-Third transistor; 104-Fourth transistor; 105-Fifth transistor; 106-Sixth transistor; W-First terminal; U-Second terminal; V-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; ILW-Current of first coil L1; Vd1-First detection signal; Vd2-Second detection signal; WO-First drive signal. Detailed Implementation

[0011] 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.

[0012] 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 may be a three-phase motor. The motor M has a first coil L1, a second coil L2, and a third coil L3. The motor controller 10 has a switching circuit 100, a control unit 110, and a detection unit 120. The switching circuit 100 has 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 W, a second terminal U, and a third terminal V, wherein the switching circuit 100 is coupled to the motor M to drive the motor M. The first terminal W, the second terminal U, and the third terminal V respectively provide a first drive signal WO, a second drive signal UO, and a third drive signal VO to drive the motor M. The first transistor 101 is coupled to a fourth terminal VCC and the first terminal W, while the second transistor 102 is coupled to the first terminal W and a fifth terminal GND. The third transistor 103 is coupled to the fourth terminal VCC and the second terminal U, while the fourth transistor 104 is coupled to the second terminal U and the fifth terminal GND. The fifth transistor 105 is coupled to the fourth terminal VCC and the third terminal V, while the sixth transistor 106 is coupled to the third terminal V and the fifth terminal GND. The system can provide a power supply voltage to the motor controller 10 via the fourth terminal VCC, enabling the motor controller 10 to operate normally. The first transistor 101, the third transistor 103, and the fifth transistor 105 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.

[0013] One end of the first coil L1 is coupled to the first end W. One end of the second coil L2 is coupled to the second end U. One end of the third coil L3 is coupled to the third end V. 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 control unit 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 conduction 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 detection unit 120 is coupled to the first end W, the second end U, and the third end V to generate a first detection signal Vd1 and a second detection signal Vd2 to the control unit 110. The detection unit 120 can be used to detect the current ILW of the first coil L1 and the back electromotive force of a floating phase. The switching circuit 100 is used to supply the current ILW of the first coil L1 to the first coil L1.

[0014] Figure 2 This is a timing diagram of an embodiment of the present invention. To address the problems of the prior art, the motor controller 10 makes a floating phase time a variable value, wherein the floating phase time has a stable interval and a detection interval. For example... Figure 2 As shown, the motor controller 10 enables the first drive signal WO to have a floating phase time, where the floating phase is formed in the first coil L1. When the current ILW of the first coil L1 is 0, the detection unit 120 changes the first detection signal Vd1 from a low level to a high level. At this time, the motor controller 10 determines whether the zero point of the current ILW falls within the stable range. Before the zero point of the current ILW appears in the stable range, the motor controller 10 makes the next floating phase time shorter than the current floating phase time to reduce noise and improve efficiency. After the zero point of the current ILW appears in the stable range, the motor controller 10 makes the next floating phase time longer than the current floating phase time to stably detect a commutation point and improve the success rate of commutation point detection. When the zero point of the current ILW appears in the stable range, the motor controller 10 makes the next floating phase time equal to the current floating phase time. Through this modulation mechanism, the motor controller 10 can make the zero point of the current ILW within the desired stable range. Then, when the detection unit 120 detects a zero-crossing point of a back electromotive force within the detection range, the detection unit 120 changes the second detection signal Vd2 from a low level to a high level to notify the control unit 110 to perform a commutation procedure. Therefore, when the power supply voltage or the load of the motor M changes, the motor controller 10 can automatically adjust the floating phase time to stably detect the commutation point and avoid noise problems.

[0015] One embodiment of the present invention utilizes a variable floating phase time technique to keep a zero point of the coil current within a stable range. The motor controller 10 can automatically adjust the floating phase time to an optimal value. Through this variable floating phase time technique, the motor controller 10 can stably detect the commutation point and avoid noise problems. The motor controller 10 can be applied to a single-phase motor or a multi-phase motor.

[0016] While the invention has been described by way of example through preferred embodiments, it should be understood that the invention is not limited to the embodiments disclosed 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 invention should be interpreted in the broadest sense to include all such modifications and similar configurations.

[0017] 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 be included within the scope of the present invention.

Claims

1. A motor controller, characterized in that, The motor controller is used to drive a motor having a coil, and the motor controller includes: A switching circuit for supplying current to a coil; and A control unit is configured to generate multiple control signals to control the switching circuit, wherein the motor controller makes a floating phase time a variable value, the floating phase time having a stable range, and when a zero point of the coil current appears before the stable range, the motor controller makes the next floating phase time less than the current floating phase time; when the zero point of the coil current appears after the stable range, the motor controller makes the next floating phase time greater than the current floating phase time; and when the zero point of the coil current appears within the stable range, the motor controller makes the next floating phase time equal to the current floating phase time.

2. The motor controller as described in claim 1, characterized in that, This motor controller is used to reliably detect a commutation point.

3. The motor controller as described in claim 1, characterized in that, The motor controller automatically adjusts the floating phase time.

4. The motor controller as described in claim 1, characterized in that, The floating phase time has a detection interval, during which the motor controller detects a zero crossover point of a back electromotive force.

5. The motor controller as described in claim 1, characterized in that, The motor controller further includes a detection unit that generates a first detection signal and a second detection signal to the control unit.

6. The motor controller as described in claim 1, characterized in that, This motor controller is applicable to a single-phase motor or a multi-phase motor.

7. A motor controller, characterized in that, The motor controller is used to drive a motor having a coil, and the motor controller includes: A switching circuit for supplying current to a coil; and A control unit is configured to generate multiple control signals to control the switching circuit, wherein the motor controller causes a zero point of the coil current to be within a stable range of a floating phase time; when the zero point of the coil current appears before the stable range, the motor controller causes the next floating phase time to be less than the current floating phase time; when the zero point of the coil current appears after the stable range, the motor controller causes the next floating phase time to be greater than the current floating phase time; and when the zero point of the coil current appears within the stable range, the motor controller causes the next floating phase time to be equal to the current floating phase time.

8. The motor controller as described in claim 7, characterized in that, This motor controller is used to reliably detect a commutation point.

9. The motor controller as described in claim 7, characterized in that, The motor controller automatically adjusts the floating phase time.

10. The motor controller as claimed in claim 7, characterized in that, The floating phase time also has a detection range, during which the motor controller detects a zero crossover point of the back electromotive force.

11. The motor controller as claimed in claim 7, characterized in that, The motor controller further includes a detection unit that generates a first detection signal and a second detection signal to the control unit.

12. The motor controller as claimed in claim 7, characterized in that, This motor controller is designed for use with a single-phase motor or a multi-phase motor.

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