TWI818488B - Motor controller - Google Patents

Abstract

A motor controller comprises a switch circuit, a driving circuit, and a pulse width modulation circuit. The switch circuit is coupled to a three-phase motor for driving the three-phase motor. The driving circuit generates a plurality of control signals to control the switch circuit. When the motor controller starts a floating phase for detecting a phase switching time point, the motor controller enables that at least one transistor within the switch circuit is operated in a linear region. The motor controller is configured to reduce switching noise of the three-phase motor and increase a success rate of phase switching.

Description

Motor controller

The present invention relates to a motor controller, and in particular to a motor controller applicable to a sensorless three-phase motor.

Traditionally, the driving methods of three-phase motors can be divided into two types. One is to use a Hall sensor to switch phases and drive a three-phase motor to run. The other is to drive a three-phase motor without a Hall sensor. Since Hall sensors are easily affected by the external environment, resulting in reduced sensing accuracy, and installing Hall sensors will increase the size and cost of the system, sensorless driving methods have been proposed to solve the above problems. problem.

In the sensorless driving method, the motor controller switches phases by detecting the back electromotive force of the floating phase, and then drives the three-phase motor. However, when the motor controller detects the back electromotive force during a floating phase time interval, it needs to continuously switch a transistor on the other two phases, thus causing the three-phase motor to generate switching noise. This switching noise will affect detection accuracy and reduce the success rate of switching phases.

In addition, when the motor controller uses the conduction time interval of a pulse width modulation signal to detect a commutation point, if the conduction time interval is too small, the voltage of the floating phase pin will not have enough time to stabilize, which will make it difficult to Detect back electromotive force. Therefore, designers can use an on-time detection mode and an off-time detection mode to detect back EMF. However, when the motor controller switches between these two detection modes, the zero point of the detected back electromotive force may be different. Furthermore, this detection method will make The motor controller cannot be used in a high frequency configuration.

In view of the above problems, the object of the present invention is to provide a motor controller that can reduce switching noise of a three-phase motor and improve the success rate of switching phases.

The motor controller is provided in accordance with the present invention. The motor controller is used to drive the three-phase motor. The motor controller has a switching circuit, a driving circuit, and a pulse width modulation circuit. The switching circuit is coupled to the three-phase motor, wherein the switching circuit includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, and a sixth transistor. , a first endpoint, a second endpoint, and a third endpoint. The first transistor and the second transistor are coupled to the first terminal. The third transistor and the fourth transistor are coupled to the second terminal. The fifth transistor and the sixth transistor are coupled to the third terminal. The driving circuit is used to generate a plurality of control signals to control the switching circuit. The pulse width modulation circuit is used to generate a pulse width modulation signal to the driving circuit, wherein the pulse width modulation signal has a duty cycle. When the motor controller turns on a floating phase to detect a commutation point, the motor controller causes the first transistor to be partially conductive. The motor controller causes the second transistor to be partially conductive. The motor controller causes the third transistor to be non-conductive or partially conductive. The motor controller causes the fourth transistor to be partially conductive or fully conductive. The motor controller causes the fifth transistor and the sixth transistor to be non-conductive. The motor controller modulates an on-resistance of the first transistor and an on-resistance of the second transistor. The motor controller does not need to enable an on-time detection mode or an off-time detection mode to detect a back electromotive force. The switch circuit further includes a fourth terminal and a fifth terminal. The first transistor, the third transistor, and the fifth transistor are coupled to the fourth terminal. The second transistor, the fourth transistor, and the sixth transistor are coupled to the fifth terminal. The motor controller detects a zero point of a back electromotive force by comparing a voltage at the third terminal with a voltage at a sixth terminal within a floating phase time interval.

According to an embodiment of the present invention, when the motor controller turns on a floating phase to detect a commutation point, the motor controller can cause at least one transistor in the switching circuit to operate in a linear region.

According to an embodiment of the present invention, when the motor controller turns on a floating phase to detect a commutation point, the motor controller can make the voltage of an output terminal of the switch circuit greater than a ground voltage and make the output The voltage at the terminal is less than an input voltage. The input voltage can be a power supply voltage.

According to an embodiment of the present invention, when the motor controller turns on a floating phase to detect a commutation point, the motor controller can operate in a voltage lock mode or a current lock mode. When the motor controller operates in the voltage locking mode, the motor controller can lock the voltage at an output terminal of the switching circuit at a specific voltage value. The specific voltage value is related to the duty cycle. The greater the duty cycle, the greater the specific voltage value. When the motor controller operates in the current locking mode, the motor controller can cause the current flowing through an output terminal of the switching circuit to be locked at a specific current value. The specific current value is related to the duty cycle. The greater the duty cycle, the greater the specific current value.

10: Motor controller

100: Switch circuit

110: Drive circuit

120: Pulse width modulation circuit

Vp: pulse width modulation signal

101:The first transistor

102: Second transistor

103:Third transistor

104: The fourth transistor

105:Fifth transistor

106:Sixth transistor

V: first endpoint

U: second endpoint

W: third endpoint

VCC: fourth endpoint

GND: fifth endpoint

COM:Sixth endpoint

C1: first control signal

C2: Second control signal

C3: The third control signal

C4: The fourth control signal

C5: The fifth control signal

C6: The sixth control signal

L1: first coil

L2: Second coil

L3: The third coil

M: Three-phase motor

WO: third voltage signal

ILW: current flowing through the third coil L3

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

Figure 2 is a timing diagram of an embodiment of the present invention.

The following description will make the objects, features, and advantages of the present invention more apparent. Preferred embodiments according to the present invention will be described in detail with reference to the drawings.

Figure 1 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 three-phase motor M, where the three-phase 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 driving circuit 110, and a pulse Wide modulation circuit 120. The switch 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, and a first terminal. Point V, a second terminal U, a third terminal W, a fourth terminal VCC, and a fifth terminal GND, wherein the switch circuit 100 is coupled to the three-phase motor M to drive the three-phase motor M. The first terminal V has a first voltage signal VO. The second terminal U has a second voltage signal UO. The third terminal W has a third voltage signal WO. The first transistor 101 is coupled to the fourth terminal VCC and the first terminal V, and the second transistor 102 is coupled to the first terminal V and the fifth terminal GND. The third transistor 103 is coupled to the fourth terminal VCC and the second terminal U, and 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 W, and 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 fifth transistor 105 can each be a P-type metal oxide semi-transistor. The second transistor 102, the fourth transistor 104, and the sixth transistor 106 may each be an N-type metal oxide semi-transistor. In addition, the fourth terminal VCC has an input voltage, where the input voltage may be a power supply voltage. The fifth terminal GND has a ground voltage. The system can provide an input voltage to the motor controller 10 through the fourth terminal VCC, so that the motor controller 10 can operate normally. For example, the input voltage may be 12 volts and the ground voltage may be 0 volts. Therefore, the motor controller 10 can be used in a high voltage configuration.

The first coil L1 is coupled to a first terminal V and a sixth terminal COM. The second coil L2 is coupled to the second terminal U and the sixth terminal COM. The third coil L3 is coupled to the third terminal W and the sixth terminal COM. That is to say, the first coil L1, the second coil L2, and the third coil L3 are arranged in a Y-shape. The driving 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 for respectively The conduction conditions 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 are controlled. The pulse width modulation circuit 120 generates a pulse width modulation signal Vp to the driving circuit 110, where the pulse width modulation signal Vp has a duty cycle. The motor controller 10 can control the rotation speed of the three-phase motor M by adjusting the working cycle.

Figure 2 is a timing diagram of an embodiment of the present invention, in which the current ILW refers to the current flowing through the third coil L3. Please refer to Figure 1 and Figure 2 at the same time. According to an embodiment of the present invention, when the motor controller 10 turns on a floating phase to detect a commutation point, the motor controller 10 can cause at least one transistor in the switching circuit 100 to operate in a linear region, wherein the floating phase Phase is formed in the third coil L3. At this time, the motor controller 10 makes the fifth transistor 105 and the sixth transistor 106 non-conductive to form a floating phase. In order to avoid generating switching noise, when the motor controller 10 turns on the floating phase to detect the commutation point, the motor controller 10 can make the voltage of the first terminal V greater than the ground voltage and make the voltage of the first terminal V less than input voltage. Specifically, when the motor controller 10 turns on the floating phase to detect the commutation point, the motor controller 10 can lock the voltage of the first terminal V at a specific voltage value according to the duty cycle of the pulse width modulation signal Vp. Or the current flowing through the first terminal V is locked at a specific current value. A specific voltage value may be associated with a duty cycle and a specific current value may be associated with a duty cycle. For example, when the duty cycle is 50%, the input voltage is 12 volts, and the ground voltage is 0 volts, the motor controller 10 can cause the voltage of the first terminal V to be locked at 6 volts. That is to say, when the motor controller 10 adopts a voltage locking mode, the larger the working cycle, the larger the specific voltage value can be. Similarly, when the motor controller 10 adopts a current locking mode, the larger the duty cycle, the larger the specific current value. Therefore, when the motor controller 10 turns on the floating phase to detect the commutation point, the motor controller 10 can reduce the switching noise of the three-phase motor M and improve the success rate of switching phases by locking the voltage mode or locking the current mode. . In addition, when the motor controller 10 turns on the floating phase to detect the commutation point, the motor controller 10 does not need to turn on an on-time detection mode or an off-time detection mode to detect a back electromotive force, so the motor control The device 10 can be used in a high frequency configuration. When the motor controller 10 turns on the floating phase to detect the commutation point, the motor controller 10 can avoid generating switching noise and increase detection accuracy through the following implementation methods:

1. When the motor controller 10 causes the fifth transistor 105 and the sixth transistor 106 to be non-conductive to form a floating phase, the floating phase is formed in the third coil L3 at this time. When the motor controller 10 causes the floating phase to be formed in the third coil L3, the motor controller 10 can cause both the first transistor 101 and the second transistor 102 to be partially conductive. That is to say, both the first transistor 101 and the second transistor 102 operate in the linear region. At this time the motor The controller 10 can cause the third transistor 103 to be non-conductive and the fourth transistor 104 to be partially conductive or fully conductive. The motor controller 10 can modulate the on-resistance of the first transistor 101 and the on-resistance of the second transistor 102 so that the motor controller 10 enters the voltage locking mode or the current locking mode to avoid generating switching noise. As shown in FIG. 2 , the motor controller 10 can detect the zero point of the back electromotive force by comparing the voltage of the third terminal W and the voltage of the sixth terminal COM within the floating phase time interval. Therefore, when the motor controller 10 turns on the floating phase to detect the commutation point, the motor controller 10 does not need to turn on the on-time detection mode or the off-time detection mode to detect the back electromotive force.

2. When the motor controller 10 causes the fifth transistor 105 and the sixth transistor 106 to be non-conductive to form a floating phase, the floating phase is formed in the third coil L3 at this time. When the motor controller 10 causes the floating phase to be formed in the third coil L3, the motor controller 10 can cause both the first transistor 101 and the second transistor 102 to be partially conductive. That is to say, both the first transistor 101 and the second transistor 102 operate in the linear region. At this time, the motor controller 10 can cause the third transistor 103 to be partially conductive and the fourth transistor 104 to be partially conductive or fully conductive. The motor controller 10 can modulate the on-resistance of the first transistor 101 and the on-resistance of the second transistor 102 so that the motor controller 10 enters the voltage locking mode or the current locking mode to avoid generating switching noise. As shown in FIG. 2 , the motor controller 10 can detect the zero point of the back electromotive force by comparing the voltage of the third terminal W and the voltage of the sixth terminal COM within the floating phase time interval. Therefore, when the motor controller 10 turns on the floating phase to detect the commutation point, the motor controller 10 does not need to turn on the on-time detection mode or the off-time detection mode to detect the back electromotive force.

3. When the motor controller 10 causes the fifth transistor 105 and the sixth transistor 106 to be non-conductive to form a floating phase, the floating phase is formed in the third coil L3 at this time. If the motor controller 10 operates at full speed, the motor controller 10 can cause the first transistor 101 to be fully conductive and the second transistor 102 to be non-conductive. That is to say, the first transistor 101 operates in a saturation region. At this time, the motor controller 10 can make the third transistor 103 non-conductive and the fourth transistor 104 partially conductive. As shown in Figure 2, the motor controller 10 can compare the voltage of the third terminal W with the voltage of the sixth terminal during the floating phase time interval. The voltage of COM is used to detect the zero point of back electromotive force. Therefore, when the motor controller 10 turns on the floating phase to detect the commutation point, the motor controller 10 does not need to turn on the on-time detection mode or the off-time detection mode to detect the back electromotive force.

According to an embodiment of the present invention, the motor controller 10 can be applied to a DC brushless motor system. In addition, the motor controller 10 can be applied in high voltage configuration and high frequency configuration. When the motor controller 10 turns on the floating phase to detect the commutation point, the motor controller 10 can operate in the voltage lock mode or the current lock mode, so that the voltage of an output terminal of the switching circuit 100 is greater than the ground voltage and causes the output terminal to The voltage is less than the input voltage. According to the above disclosed technology, the motor controller 10 can reduce the switching noise of the three-phase motor M and improve the success rate of switching phases.

Although the present invention has been illustrated by preferred embodiments, it should be understood that the present invention is not limited to the disclosed embodiments. On the contrary, the invention is intended to cover various modifications and similar arrangements obvious to those skilled in the art. Accordingly, the patentable scope should be given the broadest interpretation so as to include all such modifications and similar configurations.

The above are only preferred embodiments of the present invention, and all equivalent changes and modifications made in accordance with the patentable scope of the present invention shall fall within the scope of the present invention.

10: Motor controller

100: Switch circuit

110: Drive circuit

120: Pulse width modulation circuit

Vp: pulse width modulation signal

101:The first transistor

102: Second transistor

103:Third transistor

104: The fourth transistor

105:Fifth transistor

106:Sixth transistor

V: first endpoint

U: second endpoint

W: third endpoint

VCC: fourth endpoint

GND: fifth endpoint

COM:Sixth endpoint

C1: first control signal

C2: Second control signal

C3: The third control signal

C4: The fourth control signal

C5: The fifth control signal

C6: The sixth control signal

L1: first coil

L2: Second coil

L3: The third coil

M: Three-phase motor

ILW: current flowing through the third coil L3

Claims (40)

A motor controller used to drive a three-phase motor. The motor controller includes: a switch circuit coupled to the three-phase motor, wherein the switch circuit includes 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, the first transistor and the The second transistor is coupled to the first terminal, the third and fourth transistors are coupled to the second terminal, and the fifth and sixth transistors are coupled to the third terminal; A driving circuit for generating a plurality of control signals to control the switching circuit; and a pulse width modulation circuit for generating a pulse width modulation signal to the driving circuit, wherein the pulse width modulation signal has a working Period, when the motor controller turns on a floating phase to detect a commutation point, the motor controller causes the first transistor to be partially conductive. The motor controller described in claim 1 of the patent application, wherein the motor controller causes the second transistor to be partially conductive. The motor controller described in Item 1 of the patent application, wherein the motor controller causes the third transistor to be non-conductive. The motor controller as described in item 1 of the patent application, wherein the motor controller causes the third transistor to be partially conductive. The motor controller described in item 1 of the patent application, wherein the motor controller causes the fourth transistor to be partially conductive. The motor controller as described in item 1 of the patent application, wherein the motor controller causes the fourth transistor to be fully conductive. The motor controller described in Item 1 of the patent application, wherein the motor controller causes the fifth transistor and the sixth transistor to be non-conductive. The motor controller as described in item 1 of the patent application, wherein the motor controller modulates an on-resistance of the first transistor and an on-resistance of the second transistor. For the motor controller described in Item 1 of the patent application, the motor controller does not need to turn on an on-time detection mode or an off-time detection mode to detect a back electromotive force. A motor controller as described in item 1 of the patent application, wherein the motor controller is applied to a DC brushless motor system. A motor controller as described in item 1 of the patent application, wherein the motor controller is applied in a high-voltage configuration. A motor controller as described in item 1 of the patent application, wherein the motor controller is applied in a high-frequency configuration. A motor controller as described in item 1 of the patent application, wherein the motor controller is used to reduce switching noise of the three-phase motor. The motor controller as described in item 1 of the patent application, wherein the motor controller is used to improve the success rate of switching phases. The motor controller as described in item 1 of the patent application, wherein the switch circuit further includes a fourth terminal and a fifth terminal, the first transistor, the third transistor, and the fifth transistor. Coupled to the fourth terminal, the second transistor, the fourth transistor, and the sixth transistor are coupled to the fifth terminal, the motor controller compares the A voltage at the third terminal and a voltage at the sixth terminal are used to detect a zero point of a back electromotive force. A motor controller used to drive a three-phase motor. The motor controller includes: a switch circuit coupled to the three-phase motor to drive the three-phase motor; a drive circuit used to generate a plurality of control signals to control the switching circuit; and a pulse width modulation circuit to generate a pulse width modulation signal to the drive circuit, wherein the pulse width modulation signal has a duty cycle. When the motor controller turns on a floating When detecting a commutation point, the motor controller causes at least one transistor in the switching circuit to operate in a linear region. The motor controller as described in item 16 of the patent application, wherein the motor controller is applied in a high-voltage configuration. A motor controller as described in item 16 of the patent application, wherein the motor controller is applied in a high-frequency configuration. The motor controller as described in item 16 of the patent application, wherein the motor controller is used to reduce switching noise of the three-phase motor. The motor controller described in item 16 of the patent application, wherein the motor controller is used to improve the success rate of switching phases. For the motor controller described in Item 16 of the patent application, the motor controller does not need to turn on an on-time detection mode or an off-time detection mode to detect a back electromotive force. A motor controller used to drive a three-phase motor. The motor controller includes: a switch circuit coupled to the three-phase motor to drive the three-phase motor; a drive circuit used to generate a plurality of control signals to control the switching circuit; and a pulse width modulation circuit to generate a pulse width modulation signal to the drive circuit, wherein the pulse width modulation signal has a duty cycle. When the motor controller turns on a floating To detect a commutation point, the motor controller causes the voltage at an output terminal of the switching circuit to be greater than a ground voltage and the voltage at the output terminal to be less than an input voltage. For the motor controller described in item 22 of the patent application, the input voltage is a power supply voltage. The motor controller as described in item 22 of the patent application, wherein the motor controller causes at least one transistor in the switching circuit to operate in a linear region. A motor controller as described in item 22 of the patent application, wherein the motor controller is applied in a high-voltage configuration. A motor controller as described in item 22 of the patent application, wherein the motor controller is applied in a high-frequency configuration. A motor controller as described in item 22 of the patent application, wherein the motor controller is used to reduce switching noise of the three-phase motor. The motor controller described in item 22 of the patent application, wherein the motor controller is used to improve the success rate of switching phases. For example, in the motor controller described in Item 22 of the patent application, the motor controller does not need to turn on an on-time detection mode or an off-time detection mode to detect a back electromotive force. A motor controller used to drive a three-phase motor. The motor controller includes: a switch circuit coupled to the three-phase motor to drive the three-phase motor; a drive circuit used to generate a plurality of control signals to control the switching circuit; and a pulse width modulation circuit to generate a pulse width modulation signal to the drive circuit, wherein the pulse width modulation signal has a duty cycle. When the motor controller turns on a floating When the phase is detected to detect a commutation point, the motor controller operates in a voltage lock mode or a current lock mode, and the motor controller causes at least one transistor in the switch circuit to be partially conductive. The motor controller as described in item 30 of the patent application, wherein when the motor controller operates in the voltage locking mode, the motor controller causes the voltage at an output end of the switching circuit to be locked at a specific voltage value, and the motor controller A specific voltage value is associated with this duty cycle. For example, in the motor controller described in Item 31 of the patent application, the greater the duty cycle, the greater the specific voltage value. The motor controller as described in item 30 of the patent application, wherein when the motor controller operates in the current locking mode, the motor controller causes the current flowing through an output terminal of the switch circuit to be locked at a specific current value. , the specific current value is related to the duty cycle. For example, in the motor controller described in Item 33 of the patent application, the greater the working cycle, the greater the specific current value. The motor controller as described in item 30 of the patent application, wherein the motor controller causes at least one transistor in the switching circuit to operate in a linear region. A motor controller as described in item 30 of the patent application, wherein the motor controller is applied in a high-voltage configuration. A motor controller as described in item 30 of the patent application, wherein the motor controller is applied in a high-frequency configuration. The motor controller as described in item 30 of the patent application, wherein the motor controller uses To reduce the switching noise of the three-phase motor. The motor controller as described in item 30 of the patent application, wherein the motor controller is used to improve the success rate of switching phases. For the motor controller described in Item 30 of the patent application, the motor controller does not need to turn on an on-time detection mode or an off-time detection mode to detect a back electromotive force.

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