CN108075696B

CN108075696B - Motor and motor drive circuit

Info

Publication number: CN108075696B
Application number: CN201611036649.4A
Authority: CN
Inventors: 孙持平; 杨修文; 杨圣骞; 黄淑娟; 蒋云龙
Original assignee: Dechang Motor (Shenzhen) Co Ltd
Current assignee: Dechang Motor (Shenzhen) Co Ltd
Priority date: 2016-11-15
Filing date: 2016-11-15
Publication date: 2021-08-06
Anticipated expiration: 2036-11-15
Also published as: CN108075696A

Abstract

The invention provides a motor and a driving circuit thereof, wherein the driving circuit comprises a controllable bidirectional alternating current switch, a first detection circuit, a second detection circuit, a steering control circuit and a switch control circuit; the controllable bidirectional alternating current switch and the stator winding are connected to two ends of an alternating current power supply; the first detection circuit and the second detection circuit are used for detecting the magnetic pole position of the permanent magnet rotor and outputting a magnetic pole position signal at the output end of the permanent magnet rotor; the steering control circuit selectively outputs a magnetic pole position signal output by the first or second detection circuit to the switch control circuit according to the steering setting of the motor; the switch control circuit controls the conduction state of the controllable bidirectional alternating current switch according to the signal output by the steering control circuit and the polarity information of the alternating current power supply so as to control the motor to rotate forwards and backwards. The motor driving circuit is simple in structure and good in universality.

Description

Motor and motor drive circuit

Technical Field

The invention relates to the field of motor control, in particular to a motor and a motor driving circuit.

Background

The motor is an electromagnetic device which realizes the conversion or transmission of electric energy according to the law of electromagnetic induction. Its main function is to generate driving torque as power source of electric appliance or various machines. The single-phase permanent magnet motor is widely applied to various electric appliance products due to simple operation and convenient control. However, the forward and reverse rotation control circuit of some motors in the current market is complex in structure.

Disclosure of Invention

In view of the above, it is desirable to provide a motor driving circuit for controlling forward and reverse rotation of a motor, which has a simple structure and is convenient to operate, and a motor having the motor driving circuit.

An embodiment of the present invention provides a motor drive circuit for driving a rotor of a motor to rotate relative to a stator, the motor drive circuit including:

the controllable bidirectional alternating current switch is connected with the winding of the motor at two ends of the alternating current power supply;

the first detection circuit and the second detection circuit are respectively used for detecting the magnetic pole position of the rotor, and when the first detection circuit and the second detection circuit detect the same magnetic pole of the rotor, magnetic pole position signals with opposite phases are output;

a steering control circuit connected to the first and second detection circuits and configured to selectively output the magnetic pole position signal output from the first detection circuit or the magnetic pole position signal output from the second detection circuit to a switch control circuit according to a steering setting of the motor;

the switch control circuit is configured to control the conduction state of the controllable bidirectional alternating current switch to control the motor to rotate in a specific direction or to rotate in a direction opposite to the specific direction according to the received magnetic pole position signal and the polarity information of the alternating current power supply.

Preferably, the switch control circuit is configured to turn on the controllable bidirectional ac switch when the ac power source is in a positive half cycle and the steering control circuit outputs a first signal, or when the ac power source is in a negative half cycle and the steering control circuit outputs a second signal.

As a preferable mode, when the motor rotates in a specific direction, the steering control circuit outputs the magnetic pole position signal output by the first detection circuit to the switch control circuit; when the motor rotates in a direction opposite to the specific direction, the steering control circuit outputs the magnetic pole position signal output by the second detection circuit to the switch control circuit.

As a preferable scheme, the first detection circuit comprises a first hall sensor; the second detection circuit comprises a second Hall sensor, and the direction of the Hall sheet in the second Hall sensor facing the rotor is turned by 180 degrees relative to the direction of the Hall sheet in the first Hall sensor facing the rotor.

Preferably, in a rest position of the motor, the first hall sensor and the second hall sensor are both disposed adjacent to an N pole of the rotor, or the first hall sensor is adjacent to an N pole of the rotor, and the second hall sensor is adjacent to an S pole of the rotor.

As a preferable mode, the steering control circuit includes a switch unit, the switch unit includes first to third terminals, the first terminal is connected to the switch control circuit, the second terminal receives the magnetic pole position signal output by the first detection circuit, the third terminal receives the magnetic pole position signal output by the second detection circuit, the first terminal is selectively connected to the second terminal or the third terminal according to the steering setting of the motor, and when the first terminal is connected to the second terminal, the motor rotates in a specific direction; when the first end is connected with the third end, the motor rotates in the direction opposite to the specific direction.

As a preferable scheme, the switch unit of the steering control circuit further includes a fourth end, the fourth end is in idle connection, when the rotation direction of the motor is switched in advance during rotation of the motor, the first end is connected to the fourth end for a preset time to stop the rotor at a preset rest position, and the first end is connected to the terminal corresponding to the pre-switching direction.

As a preferable scheme, the motor driving circuit further includes a rectifier for providing a dc voltage to at least the first hall sensor and the second hall sensor, the rectifier includes a first output terminal for outputting a higher voltage and a second output terminal for outputting a lower voltage, power terminals of the first and second hall sensors are connected to the first output terminal, and ground terminals of the first and second hall sensors are connected to the second output terminal.

As a preferred scheme, the motor driving circuit further comprises a step-down transformer connected with the rectifier and used for inputting the alternating-current power supply voltage to the rectifier after the alternating-current power supply voltage is reduced, and the switch control circuit comprises a first resistor, an NPN triode, and a second resistor and a diode which are connected in series between the steering control circuit and the controllable bidirectional alternating-current switch; the cathode of the diode is connected with the steering control circuit; one end of the first resistor is connected with the first output end of the rectifier, and the other end of the first resistor is connected with the cathode of the diode; and the base electrode of the NPN triode is connected with the cathode of the diode, the emitting electrode of the NPN triode is connected with the anode of the diode, and the collector electrode of the NPN triode is connected with the first output end of the rectifier.

As a preferable scheme, the motor driving circuit further includes a control switch, the control switch is connected between the ac power supply and the motor winding, the motor is switched to rotate when the motor is running, and the control switch is turned off for a predetermined time before the motor is switched to rotate until the rotor stops at a predetermined stationary position.

An embodiment of the present invention further provides a motor driving circuit for driving a rotor of a motor to rotate relative to a stator, the motor driving circuit including:

the controllable bidirectional alternating current switch is connected between the first node and the second node, and the motor winding and an external alternating current power supply are connected between the first node and the second node in series; or the controllable bidirectional alternating current switch and the motor winding are connected in series between the first node and the second node, and the external alternating current power supply is connected between the first node and the second node;

first and second motor drive integrated circuits having the same structure, the first and second motor drive integrated circuits each including a housing, the housing including a front wall and a rear wall, the front wall of the first motor drive integrated circuit facing the rotor, the rear wall of the second motor drive integrated circuit facing the rotor, the first and second motor drive integrated circuits including:

the detection circuit is used for detecting the magnetic pole position of the rotor and outputting a magnetic pole position signal at the output end of the detection circuit;

a switch control circuit configured to output a control signal in accordance with the magnetic pole position signal output by the detection circuit and the polarity of the alternating-current power supply;

and the steering control circuit is configured to selectively output a control signal output by the first or second motor drive integrated circuit to the controllable bidirectional alternating current switch according to the steering setting of the motor so as to control the conduction state of the controllable bidirectional alternating current switch, so that the motor rotates in a specific direction or rotates in a direction opposite to the specific direction.

An embodiment of the present invention further provides a motor, including a stator, a rotor, and the motor driving circuit described in any one of the above.

Preferably, the motor is a single-phase permanent magnet alternating current motor, a single-phase permanent magnet synchronous motor or a single-phase permanent magnet BLDC motor.

The motor driving circuit provided by the embodiment of the invention detects the magnetic pole position of the rotor through two detection circuits or two motor driving integrated circuits, when the two detection circuits or the two motor driving integrated circuits detect the same magnetic pole of the rotor, magnetic pole position signals with opposite phases are output, and the steering control circuit selects the magnetic pole position signals or control signals output by the corresponding detection circuits or the motor driving integrated circuits according to the steering setting of the motor to control the state of the controllable bidirectional alternating current switch, so that the direction of current flowing through a motor stator winding is controlled, and the forward rotation or the reverse rotation of the motor is controlled. The motor driving circuit is simple in structure and high in universality.

Drawings

In the drawings:

fig. 1 shows a schematic circuit diagram of a motor according to a first embodiment of the present invention.

Fig. 2 is a schematic diagram illustrating an embodiment of positions of the first hall sensor and the second hall sensor of fig. 1 with respect to the rotor.

Fig. 3 is a schematic diagram illustrating another embodiment of the positions of the first hall sensor and the second hall sensor of fig. 1 relative to the rotor.

Fig. 4 shows a working diagram of a hall sensor.

FIG. 5 shows a circuit diagram of an embodiment of a steering control circuit.

Fig. 6 shows a schematic circuit diagram of an electric motor according to a second embodiment of the invention.

Fig. 7 shows a schematic circuit diagram of a motor according to a third embodiment of the present invention.

Fig. 8 shows a schematic circuit diagram of a motor according to a fourth embodiment of the present invention.

Fig. 9 shows a schematic circuit diagram of a motor according to a fifth embodiment of the present invention.

Fig. 10A and 10B are graphs showing a comparison between input power of a motor of the related art and input power of a motor according to an embodiment of the present invention.

Description of the main elements

The following detailed description will further illustrate the invention in conjunction with the above-described figures.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. It is to be understood that the drawings are provided solely for the purposes of reference and illustration and are not intended as a definition of the limits of the invention. The connections shown in the drawings are for clarity of description only and are not limiting as to the manner of connection.

It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

Referring to fig. 1 and 2, a schematic circuit diagram of a motor 10 according to a first embodiment of the present invention is shown, wherein the motor 10 can rotate in two directions. The electrical machine 10 comprises a stator and a rotor 11 rotatable relative to the stator. The stator includes a stator core and a stator winding 16 wound around the stator core. The stator core can be made of soft magnetic materials such as pure iron, cast steel, electrical steel, silicon steel, ferrite and the like. The rotor 11 is a permanent magnet rotor and the rotor 11 is operated at a constant speed during steady state when the stator winding 16 is connected to an ac power supply 24, where f is the frequency of said ac power supply and p is the number of pole pairs of the rotor, at 60f/p turns/min. In this embodiment, the stator core has two opposite pole portions (not shown). Each pole portion has a pole arc face with which the outer surface of the rotor opposes to form a substantially uniform air gap therebetween. The term substantially uniform air gap as used herein means that a majority of the air gap between the stator and the rotor is uniform and only a minority of the air gap is non-uniform. Preferably, the pole arc surface of the stator pole part is provided with an inward starting groove, and the part of the pole arc surface except the starting groove is concentric with the rotor 11. The above configuration can form an uneven magnetic field, allowing the motor 10 to have a starting torque of the rotor 11 at each energization by a motor drive circuit 19. In the present embodiment, the stator and the rotor 11 each have two magnetic poles. It will be appreciated that in further embodiments the number of poles of the stator and rotor may be unequal, with further poles, for example four, six, etc.

The stator winding 16 of the motor 10 and the motor drive circuit 19 are connected in series across an ac power supply 24. The motor driving circuit 19 can control the forward and reverse rotation of the motor. The ac power source 24 may be a commercial ac power of 220 volts, 230 volts, etc., or an ac power output by an inverter.

The motor driving circuit 19 includes a first detection circuit, a second detection circuit, a rectifier, a controllable bidirectional ac switch 26, a switch control circuit 30, and a steering control circuit 50. A controllable bidirectional ac switch 26 is connected between the first node a and the second node B, and the motor stator winding 16 and the ac power source 24 are connected in series between the first node a and the second node B. The first input end I1 of the rectifier is connected with the first node A through a resistor R0, the second input end I2 of the rectifier is connected with the second node B, and the rectifier is used for converting alternating current power into direct current and supplying the direct current to the first detection circuit and the second detection circuit.

In other embodiments, the stator winding 16 and the controllable bidirectional ac switch 26 are connected in series between the first node a and the second node B, and the external ac power source 24 is connected between the first node a and the second node B.

The first detection circuit and the second detection circuit respectively detect the magnetic pole position of the motor rotor 11, and output corresponding magnetic pole position signals, such as 5V or 0V, at the output end of the first detection circuit and the second detection circuit. The first and second detection circuits are preferably hall sensors, such as linear hall sensors or switch type hall sensors, which are respectively referred to as the first hall sensor 22 and the second hall sensor 23 in this embodiment. In other embodiments, the first and second detection circuits may be photoelectric encoders. The first hall sensor 22 and the second hall sensor 23 each include a power supply terminal VCC, a ground terminal GND, and an output terminal H1. In the present embodiment, when the first hall sensor 22 and the second hall sensor 23 sense the magnetic poles of the same polarity of the rotor 11, magnetic pole position signals having opposite phases are output.

The first hall sensor 22 and the second hall sensor 23 have the same structure, are both integrated circuits, and include a housing including a front wall and a rear wall, and a hall sheet (hall plate)220 and a signal amplifier 222 (see fig. 4) are provided in the housing. When the motor 10 is used, the front wall of the first hall sensor 22 faces the rotor 11, and the rear wall of the second hall sensor 23 faces the rotor 11. In the rest position of the motor, the first hall sensor 22 is arranged with a counterclockwise offset with respect to the polar axis R of the rotor 11 so as to form an angle; the second hall sensor 23 is disposed in a clockwise offset manner with respect to the polar axis R of the rotor 11 to form an included angle, and in the present embodiment, the two included angles are equal and are both marked as α. A virtual line passing through the centers of two diametrically opposed magnetic poles (two magnets in this embodiment) of the rotor 11 is denoted as a polar axis R of the rotor. In the embodiment shown in fig. 2, the first hall sensor 22 and the second hall sensor 23 are both disposed adjacent to the same magnetic pole, such as North pole (North, N pole), of the rotor 11. In other embodiments, as shown in fig. 3, the first hall sensor 22 and the second hall sensor 23 are disposed adjacent to different magnetic poles of the rotor 11, such as the first hall sensor 22 is disposed adjacent to an N pole of the rotor, and the second hall sensor 23 is disposed adjacent to a South pole (S pole) of the rotor 11. Those skilled in the art will appreciate that the rotor 11 may comprise pairs of poles, the included angle being less than 90 degrees/N in electrical degrees, N being the number of pairs of poles of the rotor. In this embodiment, the included angle α ranges from 0 degree to 90/N degrees, i.e., the included angle α is greater than or equal to 0 degree and less than 45 degrees. Preferably, the included angle may be 0 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, or 40 degrees. When the first and

second hall sensors

22 and 23 are provided, the first and

second hall sensors

22 and 23 are located away from a zero-crossing point region of the rotor magnetic field, i.e., a region where the rotor magnetic field is weakest, at a predetermined stationary position of the rotor, so that the rotor can be smoothly started.

The steering control circuit 50 is connected to the first hall sensor 22 and the second hall sensor 23, and configured to selectively output the magnetic pole position signal output from the first hall sensor 22 or the magnetic pole position signal output from the second hall sensor 23 to the switch control circuit 30 according to the steering setting of the motor. The switch control circuit 30 controls the controllable bidirectional ac switch 26 to switch between on and off states in a predetermined manner according to the received magnetic pole position signal and the polarity information of the ac power source to control the forward rotation or reverse rotation of the motor.

The rectifier includes four diodes D2-D5. The cathode of the diode D2 is connected to the anode of the diode D3, the cathode of the diode D3 is connected to the cathode of the diode D4, the anode of the diode D4 is connected to the cathode of the diode D5, and the anode of the diode D5 is connected to the anode of the diode D2. The cathode of the diode D2 is connected as a first input I1 of the rectifier via a resistor R0 to the first node a. The resistor R0 may act as a voltage reducer. The anode of the diode D4 is connected to the second node B as the second input I2 of the rectifier. The cathode of the diode D3 is used as the first output terminal O1 of the rectifier and is connected to the power supply terminals VCC of the first hall sensor 22 and the second hall sensor 23, and the first output terminal O1 outputs a higher dc operating voltage. The anode of the diode D5 is connected to the ground GND of the first hall sensor 22 and the second hall sensor 23 as the second output terminal O2 of the rectifier, and the second output terminal O2 outputs a lower voltage than the first output terminal. A zener diode Z1 is connected between the first output terminal O1 and the second output terminal O2 of the rectifier, an anode of the zener diode Z1 is connected to the second output terminal O2, and a cathode of the zener diode Z1 is connected to the first output terminal O1.

In the present embodiment, the output terminals H1 of the first hall sensor 22 and the second hall sensor 23 are connected to the steering control circuit 50. In the case where the first hall sensor 22 is normally powered, i.e., the power supply terminal VCC receives a higher voltage, the ground terminal GND receives a lower voltage, if the detected magnetic field of the rotor is N-pole, the output terminal H1 outputs a magnetic pole position signal of logic high level, and if S-pole is detected, the output terminal H1 outputs a magnetic pole position signal of logic low level. In the case where the second hall sensor 23 is normally powered, that is, the power supply terminal VCC receives a higher voltage, the ground terminal GND receives a lower voltage, if the detected magnetic field of the rotor is an N pole, the output terminal H1 outputs a magnetic pole position signal of a logic low level, and if an S pole is detected, the output terminal H1 outputs a magnetic pole position signal of a logic high level.

The principle that the first hall sensor 22 and the second hall sensor 23 detect that the same-polarity magnetic poles output magnetic pole position signals with opposite phases will be described. Referring to fig. 4, the hall sheet 220 includes a front wall X and a rear wall Y, and when the hall sheet 220 is packaged in the housing of the hall sensor, the front wall X corresponds to the front wall of the housing of the hall sensor, and the rear wall corresponds to the rear wall of the housing of the hall sensor. The hall sheet 220 further includes two excitation current terminals M, N (corresponding to the power terminal VCC and the ground terminal GND in fig. 1, respectively), and two hall electromotive force output terminals C, D, and the two input terminals of the signal amplifier 222 are connected to the two hall electromotive force output terminals C, D, respectively. The first and

second hall sensors

22 and 23 are described as sensing N. Because the front wall of the first hall sensor 22 faces the rotor 11, when sensing that the magnetic pole of the rotor 11 is an N pole, the hall sheet 220 of the first hall sensor 22 is placed in a magnetic field with a magnetic induction intensity of B, and the magnetic field direction is perpendicular to the hall sheet 220 from bottom to top, as shown in fig. 4, the magnetic field direction is directed from the front wall X of the hall sheet 220 to the rear wall Y. When a current flowing from the excitation current terminal M to the excitation current terminal N flows through the hall sheet 220, electrons are deflected by the lorentz force, electrons are accumulated at the hall electromotive force output terminal C, and the hall electromotive force output terminal D lacks electrons, so that the hall electromotive force output terminal C is negatively charged, the hall electromotive force output terminal D is positively charged, a hall electromotive force is generated in a direction perpendicular to the current and the magnetic field, that is, between the hall electromotive force output terminals C, D, the hall electromotive force is amplified by the signal amplifier 222 and a magnetic pole position signal in the form of a digital signal is generated, and at this time, the magnetic pole position signal is a logic high level "1" and is output from the output terminal H1 of the hall sensor. Because of the back wall of second hall sensor 23 towards rotor 11, when sensing the magnetic pole of rotor and being the N utmost point, hall foil 220 of second hall sensor 23 is arranged in the magnetic field that magnetic induction is B, and the magnetic field direction is perpendicular to hall foil 220 from top to bottom, because second hall sensor 23 has carried out the upset for first hall sensor 22, looks at the magnetic field direction from second hall sensor 23 and is pointed to antetheca X by hall foil 220's back wall Y, and the direction that the magnetic field passed hall foil 220 is just opposite with the direction in fig. 4. When a current flowing from the excitation current terminal M to the excitation current terminal N flows through the hall sheet 220, electrons are accumulated at the hall electromotive force output terminal D, and the hall electromotive force output terminal C lacks electrons, so that the hall electromotive force output terminal D is negatively charged and the hall electromotive force output terminal C is positively charged, a hall electromotive force is generated in a direction perpendicular to the current and the magnetic field, that is, between the hall electromotive force output terminals C, D, and the signal amplifier 222 amplifies the hall electromotive force and generates a magnetic pole position signal in the form of a digital signal, which is a logic low level "0" and is output from the output terminal H1 of the hall sensor. When the first hall sensor 22 and the second hall sensor 23 sense the S pole of the rotor, the output terminal H1 of the first hall sensor 22 outputs a logic low level, and the output terminal H1 of the second hall sensor 23 outputs a logic high level.

To sum up, the first hall sensor 22 is mounted on the motor in a manner that the front wall faces the rotor, and the rear wall faces the rotor, so that the direction of the hall sheet in the second hall sensor 23 facing the rotor 11 is 180 degrees reversed with respect to the direction of the hall sheet in the first hall sensor 22 facing the rotor 11, and when the first and

second hall sensors

22 and 23 sense the magnetic poles of the same polarity of the rotor 11, magnetic pole position signals with opposite phases are output.

Referring to fig. 1 again, the steering control circuit 50 includes a switch unit, the switch unit includes first to third terminals 51-53, the first terminal 51 is connected to the switch control circuit 30, the second terminal 52 receives the magnetic pole position signal output by the first hall sensor 22, the third terminal 53 receives the magnetic pole position signal output by the second hall sensor 23, and the steering control circuit 50 selectively connects the first terminal 51 to the second terminal 52 or the third terminal 53 according to a steering setting signal CTRL.

The switch control circuit 30 comprises a first to a third terminal, wherein the first terminal is connected to the first output O1 of the rectifier, the second terminal is connected to the first terminal 51 of the steering control circuit 50, and the third terminal is connected to the gate G of the controllable bidirectional ac switch 26. The switch control circuit 30 includes a resistor R2, an NPN transistor Q1, and a diode D1 and a resistor R1 connected in series between the first terminal 51 of the steering control circuit 50 and the controllable bidirectional ac switch 26. The cathode of the diode D1 is connected as a second terminal of the switch control circuit 30 to the first terminal 51 of the steering control circuit 50. The resistor R2 has one end connected to the first output O1 of the rectifier 28 and the other end connected to the cathode of the diode D1. A base of the NPN transistor Q1 is connected to the cathode of the diode D1, an emitter thereof is connected to the anode of the diode D1, a collector thereof is connected to the first output terminal O1 of the rectifier 28 as the first terminal of the switch control circuit 30, and an end of the resistor R1 which is not connected to the diode D1 is used as the third terminal of the switch control circuit 30.

The controllable TRIAC 26 is preferably a TRIAC (TRIAC) having a first anode T1 connected to the second node B, a second anode T2 connected to the first node a, and a control electrode G connected to the third terminal of the switch control circuit 30. It will be appreciated that the controllable bidirectional ac switch 26 may comprise an electronic switch comprising one or more of a mosfet, a scr, a triac, an igbt, a bjt, a thyristor, and an optocoupler for bi-directional current flow. For example, two mosfets may constitute a controllable bidirectional ac switch; the two silicon controlled rectifiers can form a controllable bidirectional alternating current switch; the two insulated gate bipolar transistors can form a controllable bidirectional alternating current switch; the two bipolar junction transistors can form a controllable bidirectional alternating current switch.

The switch control circuit 30 is configured to turn on the controllable bidirectional ac switch 26 when the ac power source is positive for a half cycle and its second terminal receives a first level, or when the ac power source is negative for a half cycle and its second terminal receives a second level; when the ac power source is in the negative half cycle and its second terminal receives the first level, or when the ac power source is in the positive half cycle and its second terminal receives the second level, the controllable bidirectional ac switch 26 is not turned on. Preferably, the first level is a logic high level, and the second level is a logic low level.

The operation principle of the motor drive circuit 19 for controlling the positive and negative rotation of the pole motor will now be described.

According to the electromagnetic theory, for a single-phase permanent magnet motor, the rotation direction of the motor rotor can be changed by changing the electrifying mode of the stator winding 16. If the rotor polarity sensed by the hall sensor is N, the ac power flowing through the stator winding 16 is positive half cycle, and the motor rotates in reverse direction, e.g., counterclockwise (CCW); it will be appreciated that if the hall sensor senses that the rotor is still N-pole, making the external ac power flowing through the stator windings 16 negative for half a cycle, the motor rotor will rotate in a positive direction, e.g., Clockwise (CW). The embodiment of the present invention is designed based on the principle that the control of the forward rotation and the reverse rotation of the motor is realized by adjusting the direction of the current flowing through the stator winding 16 according to the polarity of the rotor sensed by the first and

second hall sensors

22 and 23. In this embodiment, when the first hall sensor 22 and the second hall sensor 23 both sense the same magnetic pole of the rotor, magnetic pole position signals with opposite phases are output, and the switch control circuit 30 controls the polarity of the external ac power flowing through the stator winding 16 according to the magnetic pole position signals, that is, the rotation direction of the motor can be controlled.

Table 1 shows a functional table for controlling forward and reverse rotation of the motor according to the steering setting signal CTRL.

TABLE 1

Steering setting signal CTRL	Optional detection circuit	Electric motor steering
			0	First Hall sensor	Counter clockwise
1	Second Hall sensorDevice for cleaning the skin	Clockwise

Now, taking a motor as an example, assuming that the steering setting signal CTRL outputs a logic high level "1", the first terminal 51 and the third terminal 53 of the steering control circuit 50 are connected, and the switch control circuit 30 receives the magnetic pole position signal output by the second hall sensor 23. When the motor is started, if the second hall sensor 23 senses that the magnetic pole position of the rotor is an N pole, the second hall sensor 23 outputs a magnetic pole position signal of a logic low level "0", the cathode of the diode D1 of the switch control circuit 30 receives a low level, the triode Q1 is turned off, if the alternating current power supply is in a negative half cycle when the motor is started, the alternating current power supply in the negative half cycle flows through the control pole G of the controllable bidirectional alternating current switch 26, the resistor R1 and the diode D1 to be grounded, the controllable bidirectional alternating current switch 26 is turned on, and the rotor 11 is started to rotate clockwise. If the ac power supply is in the positive half cycle when the motor is started, the ac power supply in the positive half cycle cannot pass through the NPN transistor Q1, no current flows through the control electrode G of the controllable bidirectional ac switch 26, the controllable bidirectional ac switch 26 is not turned on, and the rotor 11 does not rotate.

If the second hall sensor 23 detects that the magnetic pole of the rotor is S pole, it outputs a magnetic pole position signal of logic high level "1" to the switch control circuit 30, the cathode of the diode D1 of the switch control circuit 30 receives high level, the transistor Q1 is turned on, so the anode of the diode D1 is high level, if the ac power source is in negative half cycle when the motor is started, the ac power source in negative half cycle cannot flow through the control pole G of the controllable bidirectional ac switch 26 and the resistor R1, so the controllable bidirectional ac switch 26 is not turned on, and the rotor 11 does not rotate. If the ac power supply is in the positive half cycle when the motor is started, the ac power supply in the positive half cycle flows to the control electrode G of the controllable bidirectional ac switch 26 through the NPN transistor Q1 and the resistor R1, the controllable bidirectional ac switch 26 is turned on, the positive half cycle of the ac power supply flows through the stator winding, and the rotor 11 rotates clockwise.

If the motor is controlled to rotate reversely, i.e. counterclockwise, so that the steering setting signal CTRL outputs a logic low level "0", the first end 51 and the second end 52 of the steering control circuit 50 are connected, and the switch control circuit 30 receives the magnetic pole position signal output by the first hall sensor 22. If the first hall sensor 22 senses that the magnetic pole position of the rotor is N pole, the output terminal H1 of the first hall sensor 22 outputs a magnetic pole position signal of logic high level "1", the transistor Q1 is turned on, so the anode of the diode D1 is high level, if the ac power supply is in negative half cycle when the motor is started, the ac power supply in negative half cycle cannot flow through the control pole G and the resistor R1 of the controllable bidirectional ac switch 26, so the controllable bidirectional ac switch 26 is not turned on, and the rotor 11 does not rotate. If the alternating current power supply is in the positive half cycle when the motor is started, the alternating current power supply in the positive half cycle flows to the control electrode G of the controllable bidirectional alternating current switch 26 through the triode Q1 and the resistor R1, the controllable bidirectional alternating current switch 26 is conducted, and the motor rotor 11 starts to rotate anticlockwise.

If the first hall sensor 22 senses that the magnetic pole position of the rotor is the S pole, the output end H1 of the first hall sensor 22 outputs a magnetic pole position signal of logic low level "0", the cathode of the diode D1 receives a logic low level, the triode Q1 is turned off, if the alternating current power supply is in the negative half cycle when the motor is started, the current in the negative half cycle passes through the control pole G of the controllable bidirectional alternating current switch 26, the resistor R1 and the diode D1 and is grounded, the controllable bidirectional alternating current switch 26 is turned on, the negative half cycle of the alternating current power supply flows through the stator winding 16, and the rotor 11 starts to rotate counterclockwise. If the ac power supply is in the positive half cycle when the motor is started, the ac power supply in the positive half cycle cannot pass through the NPN transistor Q1, no current flows through the control electrode G of the controllable bidirectional ac switch 26, the controllable bidirectional ac switch 26 is not turned on, and the rotor 11 does not rotate.

The above-mentioned condition that the rotor 11 does not rotate refers to the condition when the motor is started, and after the motor is started successfully, the rotor 11 keeps inertial rotation even if the controllable bidirectional alternating current switch 26 is not conducted. In addition, when changing the rotation direction of the rotor 11, it is necessary to stop the rotation of the rotor 11 of the motor first, so that the rotor 11 is stopped at a predetermined stationary position, and the stopping of the rotation of the rotor 11 of the motor is easily achieved, for example, a switch (not shown) is added between the ac power supply 24 and the stator winding 16 of the motor, and the switch is turned off for a predetermined time to stop the rotation of the rotor 11. For example, referring to fig. 5, the switching unit of the steering control circuit 50 further includes a fourth terminal 54, the fourth terminal 54 is idle, and the state of the steering control circuit 50 is controlled by two steering setting signals CTRL1 and CTRL 2.

The following describes a process of changing the motor operation direction by taking an example. A user may output a steering setting signal CTRL1 being 0 and CTRL2 being 0 to the steering control circuit 50 through an external controller, the steering control circuit 50 connects the first end 51 with the second end 52, and selectively connects the first hall sensor 22 to the switch control circuit 30, and the motor rotates counterclockwise. After the motor is started, the motor is controlled to change the running direction in advance, an external controller can output a steering setting signal with CTRL1 being equal to 1 and CTRL2 being equal to 1, the first end 51 of the steering control circuit 50 is connected with the fourth end 54, no current flows through the control pole G of the controllable bidirectional alternating current switch 26 because the fourth end 54 is in idle connection, and the motor stops after rotating for a while along with inertia. After a certain time, the external controller outputs a steering setting signal, CTRL1 is equal to 1, CTRL2 is equal to 0, to the steering control circuit 50, the first end 51 of the steering control circuit 50 is connected to the third end 53, the second hall sensor 23 is selectively connected to the switch control circuit 30, and the motor rotates clockwise.

Please refer to table 2, which is a specific case of controlling the motor to rotate forward and backward according to the rotation direction setting of the motor, the magnetic pole position of the rotor and the polarity of the power source.

TABLE 2

Those skilled in the art will appreciate that the switch control circuit 30, the rectifier and the detection circuit can be integrated and packaged in an integrated circuit, such as an ASIC single chip, to reduce the circuit cost and improve the reliability of the circuit.

Referring to fig. 6, a circuit diagram of a second embodiment of the motor of the present invention is shown, and the present embodiment is different from the embodiment shown in fig. 1 in that two motor driving Integrated Circuits (ICs) integrating the switch control circuit 30, the rectifier and the detection circuit are used to control the forward and reverse rotation of the motor. The two motor driving integrated circuits are respectively marked as a first motor driving integrated circuit 100 and a second motor driving integrated circuit 200. The first motor drive integrated circuit 100 and the second motor drive integrated circuit 200 each include a housing, the housing includes a front wall and a rear wall, the front wall of the first motor drive integrated circuit 100 faces the rotor 11, and the rear wall of the second motor drive integrated circuit 200 faces the rotor 11. The output H1 of the hall sensor inside the first motor driving ic 100 and the second motor driving ic 200 is directly connected to the second terminal of the switch control circuit 30, unlike the first embodiment shown in fig. 1. The structures and operating principles of the switch control circuit, the rectifier and the detection circuit in the first motor driving integrated circuit 100 and the second motor driving integrated circuit 200 are the same as those in the first embodiment, and are not described herein again. The steering control circuit 50, which is not integrated within the motor drive integrated circuit, is configured to selectively output the control signal output by the first or second motor drive integrated

circuits

100, 200 to the controllable bidirectional ac switch 26 according to the steering setting of the motor, so as to control the conductive state of the controllable bidirectional ac switch 26, so that the motor is rotated in a specific direction or in a direction opposite to the specific direction. In this embodiment, the specific direction is counterclockwise, and the direction opposite to the specific direction is clockwise.

In the embodiment shown in fig. 6, a first terminal 51 of the steering control circuit 50 is connected to the control pole G of the controllable bidirectional ac switch 26, a second terminal 52 of the steering control circuit 50 is connected to a second terminal of the switch control circuit 30 of the first motor drive integrated circuit 100, and a third terminal 53 of the steering control circuit 50 is connected to a second terminal of the switch control circuit 30 of the second motor drive integrated circuit 200. The first input terminal I1 of the rectifiers of the first and second

motor drive ics

100 and 200 is connected to the first node a through a resistor R0, the second input terminal I2 of the rectifiers of the first and second

motor drive ics

100 and 200 is connected to the second node B, the first anode T1 of the controllable bidirectional ac switch 26 is connected to the second node B, the second anode T2 is connected to the first node a, and the ac power source 24 and the stator winding 16 are connected in series between the first and second nodes A, B. When the steering setting signal CTRL received by the steering control circuit 50 is at a logic low level, the first end 51 is connected to the second end 52, and the motor rotates counterclockwise; when the steering setting signal CTRL received by the steering control circuit 50 is at a logic high level, the first end 51 of the steering control circuit 50 is connected to the third end 53, and the motor rotates clockwise.

Referring to fig. 7, a circuit diagram of a third embodiment of the motor of the present invention is shown, and the difference between this embodiment and the embodiment shown in fig. 6 is that the stator winding 16 and the controllable bidirectional ac switch 26 are connected in series between the first node a and the second node B, and the ac power source 24 is connected between the first node a and the second node B.

Referring to fig. 8, a circuit diagram of a fourth embodiment of the motor driving circuit of the present invention is shown, the difference between this embodiment and the embodiment shown in fig. 6 is that the position of the steering control circuit 50 is changed, in this embodiment, a first end 51 of the steering control circuit 50 is connected to a first node a through a resistor R0, a second end 52 is connected to a first input end I1 of a rectifier of the first motor driving integrated circuit 100, and a third end 53 is connected to a first input end I1 of a rectifier of the second motor driving integrated circuit 200. The steering control circuit 50 selectively controls the ac power supply 24 to supply power to the first motor driving integrated circuit 100 or supply power to the second motor driving integrated circuit 200 according to the steering setting signal CTRL, so as to output the control signal output by the first or second motor driving

integrated circuits

100 and 200 to the controllable bidirectional ac switch 26, so as to control the on-state of the controllable bidirectional ac switch 26, and further control the forward rotation or the reverse rotation of the motor.

Referring to fig. 9, a circuit diagram of a fifth embodiment of the motor driving circuit of the present invention is shown, and the difference between this embodiment and the embodiment shown in fig. 8 is that the stator winding 16 and the controllable bidirectional ac switch 26 are connected in series between the first node a and the second node B, and the external ac power source 24 is connected between the first node a and the second node B.

In the above embodiment, the switch unit of the steering control circuit 50 may be a mechanical switch or an electronic switch, the mechanical switch includes a relay, a single-pole double-throw switch and a single-pole single-throw switch, and the electronic switch includes a solid-state relay, a metal oxide semiconductor field effect transistor, a silicon controlled rectifier, a triac, an insulated gate bipolar transistor, a bipolar junction transistor, a thyristor, an optical coupler, and the like.

Those skilled in the art will appreciate that in the embodiment shown in fig. 6 to 9, the switch unit of the steering control circuit 50 may also take the form shown in fig. 5, and the motor is controlled to stop by the steering control circuit 50 when the motor is controlled to change direction. Of course, other ways of controlling the motor to stop may be used, such as adding a control switch (not shown) between the ac power source 24 and the stator winding 16 of the motor, and turning off the control switch for a predetermined time to stop the motor rotor from rotating and stopping at a predetermined rest position.

The motor driving circuit provided by the embodiment of the invention detects the magnetic pole position of the rotor 11 through two detection circuits or two motor driving integrated circuits, when the two detection circuits or the two motor driving integrated circuits detect the same magnetic pole of the rotor, magnetic pole position signals with opposite phases are output, and the steering control circuit 50 selects the magnetic pole position signals or control signals output by the corresponding detection circuits or the motor driving integrated circuits according to the steering setting of the motor to control the state of the controllable bidirectional alternating current switch, so as to control the current direction flowing through the stator winding of the motor, and control the forward rotation or the reverse rotation of the motor. When it is desired to provide drive motors for different applications with opposite rotational directions, it is only necessary to switch the terminals at which the steering control circuit 50 is turned on. The motor driving circuit is simple in structure and high in universality.

In the above embodiment, the rotor 11 is a permanent magnet rotor, each magnetic pole of the permanent magnet rotor may be made of neodymium magnet material extracted from rare earth as a magnetic pole, or made of neodymium magnet (extracted from rare earth and also referred to as rubber magnet) wrapped with rubber as a more durable counter electromotive force in the rotor magnetic pole motor, which may be trapezoidal wave.

In the above embodiments, the rectifier circuit is a full-bridge rectifier circuit, and in other embodiments, a half-bridge rectifier circuit, a full-wave rectifier circuit, or a half-wave rectifier circuit may be used. In this embodiment, the rectified voltage is regulated by the zener diode Z1, but in other embodiments, the rectified voltage may be regulated by an electronic component such as a three-terminal regulator.

Those skilled in the art will appreciate that the motor according to the embodiments of the present invention is suitable for driving a window of an automobile, a roll screen for office or home use, and the like. The motor according to the embodiment of the invention can be a permanent magnet alternating current motor, such as a permanent magnet synchronous motor and a permanent magnet BLDC motor. The motor of the embodiment of the invention is preferably a single-phase permanent magnet alternating current motor, such as a single-phase permanent magnet synchronous motor, a single-phase permanent magnet BLDC motor. When the motor is a permanent magnet synchronous motor, the external alternating current power supply is a mains supply; when the motor is a permanent magnet BLDC motor, the external alternating current power supply is an alternating current power supply output by the inverter.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. A motor drive circuit for driving a rotor of a motor to rotate relative to a stator, the motor drive circuit comprising:

2. The motor drive circuit of claim 1 wherein the switch control circuit is configured to render the controllable bidirectional ac switch conductive when the ac power source is a positive half cycle and the steering control circuit outputs a first signal or when the ac power source is a negative half cycle and the steering control circuit outputs a second signal.

3. The motor drive circuit according to claim 1, wherein the steering control circuit outputs the magnetic pole position signal output from the first detection circuit to the switch control circuit when the motor rotates in a specific direction; when the motor rotates in a direction opposite to the specific direction, the steering control circuit outputs the magnetic pole position signal output by the second detection circuit to the switch control circuit.

4. The motor drive circuit of claim 1 wherein the first detection circuit comprises a first hall sensor; the second detection circuit comprises a second Hall sensor, and the direction of the Hall sheet in the second Hall sensor facing the rotor is turned by 180 degrees relative to the direction of the Hall sheet in the first Hall sensor facing the rotor.

5. The motor drive circuit according to claim 4, wherein in the motor rest position, the first hall sensor and the second hall sensor are both disposed adjacent to an N pole of the rotor, or the first hall sensor is adjacent to an N pole of the rotor, and the second hall sensor is adjacent to an S pole of the rotor.

6. The motor drive circuit according to claim 1, wherein the steering control circuit includes a switching unit including first to third terminals, the first terminal being connected to the switching control circuit, the second terminal receiving the magnetic pole position signal output from the first detection circuit, the third terminal receiving the magnetic pole position signal output from the second detection circuit, the first terminal being selectively connected to either the second terminal or the third terminal according to a steering setting of the motor, the motor being rotated in a specific direction when the first terminal is connected to the second terminal; when the first end is connected with the third end, the motor rotates in the direction opposite to the specific direction.

7. The motor driving circuit according to claim 6, wherein the switching unit of the steering control circuit further includes a fourth terminal, the fourth terminal is idle-connected, when the motor rotates in the pre-switching direction, the first terminal is connected to the fourth terminal for a predetermined time to stop the rotor at the predetermined rest position, and the first terminal is connected to the terminal corresponding to the pre-switching direction.

8. The motor drive circuit according to claim 4, further comprising a rectifier for supplying a dc voltage to at least the first hall sensor and the second hall sensor, wherein the rectifier includes a first output terminal outputting a higher voltage and a second output terminal outputting a lower voltage, power terminals of the first and second hall sensors are connected to the first output terminal, and ground terminals of the first and second hall sensors are connected to the second output terminal.

9. The motor drive circuit of claim 8 further comprising a step-down converter coupled to said rectifier for stepping down an ac power voltage for input to said rectifier, said switch control circuit comprising a first resistor, an NPN transistor, and a second resistor and diode coupled in series between a steering control circuit and said controllable bidirectional ac switch; the cathode of the diode is connected with the steering control circuit; one end of the first resistor is connected with the first output end of the rectifier, and the other end of the first resistor is connected with the cathode of the diode; and the base electrode of the NPN triode is connected with the cathode of the diode, the emitting electrode of the NPN triode is connected with the anode of the diode, and the collector electrode of the NPN triode is connected with the first output end of the rectifier.

10. The motor drive circuit of claim 1 further comprising a control switch connected between said ac power source and the motor windings, wherein the motor is operated to switch the motor direction, and wherein said control switch is turned off for a predetermined time before switching the motor direction until said rotor stops at a predetermined rest position.

11. A motor drive circuit for driving a rotor of a motor to rotate relative to a stator, the motor drive circuit comprising:

12. An electric machine comprising a stator, a rotor and a motor drive circuit as claimed in any one of claims 1 to 11.

13. The motor of claim 12, wherein the motor is a single-phase permanent magnet ac motor, a single-phase permanent magnet synchronous motor, or a single-phase permanent magnet BLDC motor.