TWI749948B - 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 three-phase motor is operated in a start state, the motor controller may enable an electric period to be divided into more floating phase time intervals for switching phases, so as to increase the success rate of phase switching. When the three-phase motor is operated in a stable state, the motor controller may enable the electric period to be divided into less floating phase time intervals for switching phases, so as to reduce the noise and vibration of the three-phase motor.

Description

Motor controller

The present invention relates to a motor controller, in particular to a motor controller which can be applied to a three-phase motor without a sensor.

Traditionally, three-phase motors can be driven in two ways. One is to use the Hall sensor to switch the phase to drive the three-phase motor to run. The other is to drive a three-phase motor without a Hall sensor. Since the Hall sensor is easily affected by the external environment and the accuracy of the sensing is reduced, and the installation of the Hall sensor will increase the size and cost of the system, a driving method without a sensor has been proposed to solve the above problems. problem.

In the sensorless driving method, the motor controller will switch the phase by detecting the back electromotive force of the floating phase, and then drive the three-phase motor. However, when the motor controller detects the back EMF during a floating phase time interval, a discontinuous phase current will be generated during the floating phase time interval, causing noise and vibration in the three-phase motor. Therefore, reducing the noise and vibration of a three-phase motor is a goal.

In view of the foregoing problems, the object of the present invention is to provide a motor controller that can reduce the noise and vibration of a three-phase motor.

According to the present invention, the motor controller is provided. The motor controller is used to drive a three-phase horse The three-phase motor has a first coil, a second coil, and a third coil. The motor controller has a switch circuit, a drive circuit, and a pulse width modulation circuit. The switch circuit has a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a first terminal, and a second terminal Point and a third end point, wherein the switch circuit is coupled to the three-phase motor to drive the three-phase motor. 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. In addition, 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. In other words, the first coil, the second coil, and the third coil are arranged in a Y-shaped manner. The driving circuit 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 first transistor respectively , The conduction status of the second transistor, the third transistor, the fourth transistor, the fifth transistor, and the sixth transistor. The pulse width modulation circuit generates a pulse width modulation signal to the driving circuit, wherein the pulse width modulation signal has a duty cycle. The motor controller can control a rotation speed of the three-phase motor by adjusting the duty cycle.

When the three-phase motor is operating in a starting state, the motor controller can divide an electrical cycle into more floating phase time intervals to switch phases, thereby increasing the success rate of commutation. When the three-phase motor is operating in a stable state, the motor controller can divide the electrical cycle into fewer floating phase time intervals to switch phases, thereby reducing the noise and vibration of the three-phase motor. That is, the motor controller first divides the electrical cycle into N1 floating phase time intervals to switch phases. After the three-phase motor operates for a first time, the motor controller divides the electrical cycle into N2 floating phase time intervals to switch phases, where both N1 and N2 are a positive integer and N1>N2. When the electrical cycle is divided into N1 floating phase time intervals, the three-phase motor operates in a starting mode. When the electrical cycle is divided into N2 floating phase time intervals, the three-phase motor operates in a steady state mode.

10: Motor controller

VCC: Endpoint

GND: terminal

100: switch circuit

110: drive circuit

120: Pulse width modulation circuit

Vp: Pulse width modulation signal

101: first transistor

102: second transistor

103: Third Transistor

104: Fourth Transistor

105: Fifth Transistor

106: Sixth Transistor

U: first endpoint

V: second endpoint

W: third terminal

C1: The first control signal

C2: second control signal

C3: Third control signal

C4: Fourth control signal

C5: Fifth control signal

C6: The sixth control signal

L1: first coil

L2: second coil

L3: third coil

M: Three-phase motor

UO: the first voltage signal

VO: second voltage signal

WO: third voltage signal

T: electrical cycle

T1: The first floating phase time interval

T2: The second floating phase time interval

T3: The third floating phase time interval

T4: The fourth floating phase time interval

T5: Fifth floating phase time interval

T6: The sixth floating phase time interval

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

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

Figure 3 is a second timing diagram of an embodiment of the present invention.

Figure 4 is a third timing diagram of an embodiment of the present invention.

Figure 5 is a fourth timing diagram of an embodiment of the present invention.

The following description will make the purpose, features, and advantages of the present invention more obvious. The 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, wherein 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 width modulation circuit 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, and a first terminal At point U, a second terminal V, and a third terminal W, the switch circuit 100 is coupled to the three-phase motor M to drive the three-phase motor M. The first terminal U has a first voltage signal UO. The second terminal V has a second voltage signal VO. The third terminal W has a third voltage signal WO. The first transistor 101 is coupled to a terminal VCC and a first terminal U, and the second transistor 102 is coupled to a first terminal U and a terminal GND. The third transistor 103 is coupled to the terminal VCC and the second terminal V, and the fourth transistor 104 is coupled to the second terminal V and the terminal GND. The fifth transistor 105 is coupled to the terminal VCC and the third terminal W, and the sixth transistor 106 is coupled to the third terminal W and the terminal GND. The first transistor 101, the third transistor 103, and the third transistor 103 can each be a P-type metal oxide semi-transistor. The second transistor 102, the fourth transistor 104, and The sixth transistor 106 can be an N-type metal oxide semi-transistor, respectively.

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. In addition, the other end of the first coil L1 is coupled to the other end of the second coil L2 and the other end of the third coil L3. In other words, 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, respectively 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. The pulse width modulation circuit 120 generates a pulse width modulation signal Vp to the driving circuit 110, wherein the pulse width modulation signal Vp has a duty cycle (Duty Cycle). The motor controller 10 can control the rotation speed of the three-phase motor M by adjusting the duty cycle.

Figure 2 is the first timing diagram of an embodiment of the present invention. The motor controller 10 divides the electrical cycle T into 6 floating phase time intervals to detect the back electromotive force and switch the phase. When the three-phase motor M is operating in a starting state, since the operation of the three-phase motor M is not yet stable at this time, 6 floating phase time intervals can be used to detect the back electromotive force. For example, the motor controller 10 may sequentially operate in the first floating phase time interval T1, the second floating phase time interval T2, the third floating phase time interval T3, the fourth floating phase time interval T4, and the fifth floating phase time interval T4. The floating phase time interval T5 and the sixth floating phase time interval T6 are used to detect the commutation point to drive the three-phase motor M. The motor controller 10 conducts the third coil L3 and the second coil L2 during the first floating phase time interval T1, so that the floating phase is formed in the first coil L1. At this time, the motor controller 10 can detect the commutation point by detecting the first voltage signal UO. The motor controller 10 conducts the first coil L1 and the second coil L2 during the second floating phase time interval T2, so that the floating phase is formed in the third coil L3. At this time, the motor controller 10 can detect the commutation point by detecting the third voltage signal WO. The motor controller 10 conducts the first coil L1 and the third coil L3 during the third floating phase time interval T3, so that the floating phase is formed in the second coil L2. At this time, the motor controller 10 can detect the commutation point by detecting the second voltage signal VO. The motor controller 10 is in the fourth floating phase time interval T4 conducts the second coil L2 and the third coil L3 so that the floating phase is formed in the first coil L1. At this time, the motor controller 10 can detect the commutation point by detecting the first voltage signal UO. The motor controller 10 conducts the second coil L2 and the first coil L1 during the fifth floating phase time interval T5, so that the floating phase is formed in the third coil L3. At this time, the motor controller 10 can detect the commutation point by detecting the third voltage signal WO. The motor controller 10 conducts the third coil L3 and the first coil L1 during the sixth floating phase time interval T6, so that the floating phase is formed in the second coil L2. At this time, the motor controller 10 can detect the commutation point by detecting the second voltage signal VO. In addition, the motor controller 10 can gradually change the duty cycle of the pulse width modulation signal Vp at the boundary of a floating phase time interval to modulate the one-phase current, so that the phase current can be smoothly changed to reduce the noise of the three-phase motor M And vibration. Figure 3 is a second timing diagram of an embodiment of the present invention. The motor controller 10 divides the electrical cycle T into three floating phase time intervals to detect the back electromotive force and switch the phase. Figure 4 is a third timing diagram of an embodiment of the present invention. The motor controller 10 divides the electrical cycle T into two floating phase time intervals to detect the back electromotive force and switch the phase. Figure 5 is a fourth timing diagram of an embodiment of the present invention. The motor controller 10 divides the electrical cycle T into one floating phase time interval to detect the back electromotive force and switch the phase.

Specifically, when the three-phase motor M operates in a starting state, the motor controller 10 can divide the electrical cycle T into more floating phase time intervals to switch phases, thereby increasing the success rate of commutation. When the three-phase motor M is operating in a stable state, the motor controller 10 can divide the electrical cycle T into fewer floating phase time intervals to switch phases, thereby reducing the noise and vibration of the three-phase motor M. In other words, the motor controller 10 first divides an electrical cycle into N1 floating phase time intervals to switch phases. After the three-phase motor M operates for a first time, the motor controller 10 divides the electrical cycle into N2 floating phase time intervals to switch phases, where N1 and N2 are both a positive integer and N1>N2. When the electrical cycle is divided into N1 floating phase time intervals, the three-phase motor M operates in a starting state. When the electrical cycle is divided into N2 floating phase time intervals, the three-phase motor M operates in a stable state. According to the above rules, there can be at least 7 or more implementation examples as follows:

1. The motor controller 10 first divides the electrical cycle into 6 floating phase time intervals for switching Phase. After the three-phase motor M operates for a first time, the motor controller 10 divides the electrical cycle into one floating phase time interval to switch phases.

2. The motor controller 10 first divides the electrical cycle into 6 floating phase time intervals to switch phases. After the three-phase motor M operates for a first time, the motor controller 10 divides the electrical cycle into two floating phase time intervals to switch phases.

3. The motor controller 10 first divides the electrical cycle into 6 floating phase time intervals to switch phases. After the three-phase motor M operates for a first time, the motor controller 10 divides the electrical cycle into two floating phase time intervals to switch phases. After the three-phase motor M operates for a second time, the motor controller 10 divides the electrical cycle into a floating phase time interval to switch phases, wherein the second time is greater than the first time.

4. The motor controller 10 first divides the electrical cycle into 6 floating phase time intervals to switch phases. After the three-phase motor M operates for a first time, the motor controller 10 divides the electrical cycle into three floating phase time intervals to switch phases.

5. The motor controller 10 first divides the electrical cycle into 6 floating phase time intervals to switch phases. After the three-phase motor M operates for a first time, the motor controller 10 divides the electrical cycle into three floating phase time intervals to switch phases. After the three-phase motor M operates for a second time, the motor controller 10 divides the electrical cycle into a floating phase time interval to switch phases, wherein the second time is greater than the first time.

6. The motor controller 10 first divides the electrical cycle into 3 floating phase time intervals to switch phases. After the three-phase motor M operates for a first time, the motor controller 10 divides the electrical cycle into one floating phase time interval to switch phases.

7. The motor controller 10 first divides the electrical cycle into two floating phase time intervals to switch phases. After the three-phase motor M operates for a first time, the motor controller 10 divides the electrical cycle into one floating phase time interval to switch phases.

Although the present invention has been described with the preferred embodiment as an example, it should be understood that the present invention is not limited to the disclosed embodiment. On the contrary, the present invention is intended to cover various modifications and similar configurations that are obvious to those familiar with the art. Therefore, the scope of the patent application should be based on the broadest interpretation to include all such modifications and similar configurations.

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

10: Motor controller

VCC: Endpoint

GND: terminal

100: switch circuit

110: drive circuit

120: Pulse width modulation circuit

Vp: Pulse width modulation signal

101: first transistor

102: second transistor

103: Third Transistor

104: Fourth Transistor

105: Fifth Transistor

106: Sixth Transistor

U: first endpoint

V: second endpoint

W: third terminal

C1: The first control signal

C2: second control signal

C3: Third control signal

C4: Fourth control signal

C5: Fifth control signal

C6: The sixth control signal

L1: first coil

L2: second coil

L3: third coil

M: Three-phase motor

Claims (12)

A motor controller is used to drive a three-phase motor. The three-phase motor has a first coil, a second coil, and a third coil. The motor controller includes: a switch circuit coupled to the three-phase motor, wherein The switch circuit includes a first terminal, a second terminal, and a third terminal; a driving circuit for generating a plurality of control signals to control the switch circuit; and a pulse width modulation circuit for To generate a pulse width modulation signal to the driving circuit, where the pulse width modulation signal has a duty cycle, the motor controller first divides an electrical cycle into N1 floating phase time intervals to switch phases, when the three-phase horse After operating for a first time, the motor controller divides the electrical cycle into N2 floating phase time intervals to switch phases. Both N1 and N2 are a positive integer and N1>N2. The motor controller described in claim 1, wherein an end of the first coil is coupled to the first end, an end of the second coil is coupled to the second end, and the third coil is One end is coupled to the third end. The motor controller described in claim 1, wherein the switch circuit further includes: a first transistor coupled to a fourth terminal and the first terminal; and a second transistor coupled to a A fifth terminal and the first terminal; a third transistor coupled to the fourth terminal and the second terminal; a fourth transistor coupled to the fifth terminal and the second terminal ; A fifth transistor, coupled to the fourth terminal and the third terminal; and a sixth transistor, coupled to the fifth terminal and the third terminal. According to the motor controller described in claim 1, wherein the motor controller gradually changes the duty cycle at a junction of a floating phase time interval to modulate a phase current. For the motor controller described in item 1 of the scope of patent application, when the electrical cycle is divided into N1 floating phase time intervals, the three-phase motor operates in a starting state, and when the electrical cycle is divided into N2 floating phases During the time interval, the three-phase motor operates in a stable state. For the motor controller described in item 1 of the scope of patent application, the motor controller first divides the electrical cycle into 6 floating phase time intervals to switch phases, and when the three-phase motor operates for the first time, the The motor controller divides the electrical cycle into 1 floating phase time interval to switch phases. For the motor controller described in item 1 of the scope of patent application, the motor controller first divides the electrical cycle into 6 floating phase time intervals to switch phases, and when the three-phase motor operates for the first time, the The motor controller divides the electrical cycle into 2 floating phase time intervals to switch phases. For the motor controller described in item 1 of the scope of patent application, the motor controller first divides the electrical cycle into 6 floating phase time intervals to switch phases, and when the three-phase motor operates for the first time, the The motor controller divides the electrical cycle into two floating phase time intervals to switch phases. When the three-phase motor operates for a second time, the motor controller divides the electrical cycle into one floating phase time interval to switch Phase, the second time is greater than the first time. For the motor controller described in item 1 of the scope of patent application, the motor controller first divides the electrical cycle into 6 floating phase time intervals to switch phases, and when the three-phase motor operates for the first time, the The motor controller divides the electrical cycle into 3 floating phase time intervals to switch phases. For the motor controller described in item 1 of the scope of patent application, the motor controller first divides the electrical cycle into 6 floating phase time intervals to switch phases, and when the three-phase motor operates for the first time, the The motor controller divides the electrical cycle into 3 floating phase time intervals to switch phases. When the three-phase motor operates for a second time, the motor controller divides the electrical cycle into 1 floating phase time interval to switch Phase, the second time is greater than the first time. For the motor controller described in item 1 of the scope of patent application, the motor controller first divides the electrical cycle into 3 floating phase time intervals to switch phases, and when the three-phase motor operates for the first time, the The motor controller divides the electrical cycle into 1 floating phase time interval to switch phases. For the motor controller described in item 1 of the scope of patent application, the motor controller first divides the electrical cycle into two floating phase time intervals to switch phases. When the three-phase motor operates for the first time, the The motor controller divides the electrical cycle into 1 floating phase time interval to switch phases.

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