WO2014044005A1

WO2014044005A1 - Six-phase dc square-wave permanent magnet brushless motor

Info

Publication number: WO2014044005A1
Application number: PCT/CN2012/087117
Authority: WO
Inventors: 马泽希; 丁杰; 薛卫波
Original assignee: 西安磁林电气有限公司
Priority date: 2012-09-20
Filing date: 2012-12-21
Publication date: 2014-03-27
Also published as: CN102868343B; CN102868343A

Abstract

A six-phase DC square-wave permanent magnet brushless motor is provided. The motor comprises a controller, a driving circuit of a bootstrap winding, an inductance value detection circuit group of no energized windings under excitation pulses and a brushless motor body. The controller is connected to the brushless motor body through the driving circuit of the bootstrap winding and the inductance value detection circuit group of the no energized windings under the excitation pulses respectively. The motor can achieve commutation effect of a brushless motor with position sensors, and can eliminate the torque ripple, and has advantages of simple structure and processing convenience.

Description

Six-phase DC square wave permanent magnet brushless motor

The invention belongs to the field of electromechanical technology, and relates to a six-phase DC square wave permanent magnet brushless motor, in particular to a DC square wave slotless permanent magnet brushless motor with a six-phase position sensorless.

Background technique

In the position sensorless rotor position detection of the existing three-phase brushless motor, by measuring the positive center moment of the magnetic pole junction of the non-energized winding, and then delaying the 30° electrical angle for commutation, and the 30° electrical angle is related to the motor speed, The delay time is often calculated according to the magnitude of the rotational speed, and the commutation is implemented. If the speed caused by the load changes irregularly, the calculated delay time is not accurate, especially in the case of low speed or even locked, the accuracy of commutation is more difficult to guarantee.

Summary of the invention

In order to solve the above-mentioned technical problems existing in the background art, the present invention provides a six-phase direct current method capable of providing a commutation effect of a brushless motor equivalent to a position sensor, six-phase complete elimination of torque ripple, simple structure, and ease of processing. Wave permanent magnet brushless motor.

The technical solution of the present invention is: The present invention provides a six-phase DC square wave permanent magnet brushless motor, which is special in that: the six-phase DC square wave permanent magnet brushless motor comprises a controller and a bootstrap winding a driving circuit, a non-energized winding inductance value detecting circuit group under the excitation pulse, and a brushless motor body; wherein the controller is connected to the brushless motor through the bootstrap winding driving circuit and the non-energized winding inductance value detecting circuit group under the excitation pulse body.

The non-energized winding inductance value detecting circuit group under the excitation pulse includes six sets of non-energized winding inductance value detecting circuits under the same excitation pulse; the non-energized winding inductance value detecting circuits under each set of excitation pulses respectively correspond to the access no Brush the motor body.

The non-energized winding inductance value detecting circuit under the excitation pulse comprises a centering power source, an optocoupler isolation excitation pulse source, a first motor phase voltage clamping circuit, a second motor phase voltage clamping circuit and an armature inductance measuring symmetric comparison circuit; The centering power source, the optocoupler isolation excitation pulse source, the first motor phase voltage clamping circuit, the second motor phase voltage clamping circuit, and the armature inductance measurement symmetric comparison circuit are sequentially connected in parallel; the controller is connected to the optocoupler isolation Excitation pulse source; the first motor phase voltage clamped The circuit and the second motor phase voltage clamping circuit are connected in parallel and connected to the brushless motor body.

The centering power supply includes a power input end, a ground end, a first resistor, a second resistor, a Zener tube, and a capacitor; the power input end is respectively connected to the Zener tube and the capacitor through the first resistor; After the capacitors are connected in parallel, they are connected to the ground through the second resistor;

The optocoupler isolation excitation pulse source includes a first photocoupler, a third resistor, a fourth resistor, a first triode, and a second triode; the third resistor is connected to the controller through the first optocoupler The first resistor is sequentially connected to the second resistor through the fourth resistor and the first photocoupler; the first resistor is sequentially connected to the second resistor through the first transistor and the second transistor; a triode is connected in parallel with the fourth resistor; the second triode is connected in parallel with the first photocoupler;

The first motor phase voltage clamping circuit includes a second diode, a third diode, and a fifth resistor; the fifth resistor is connected to the first resistor through the second diode; The third diode is connected to the second resistor; the fifth resistor is respectively connected to the first triode and the second triode; and the second motor phase voltage clamping circuit comprises a sixth resistor and a fourth diode And a fifth diode; one end of the sixth resistor is connected to the fifth resistor, and the other end is respectively connected to the first resistor and the second resistor through the fourth diode and the fifth diode;

The armature inductance measuring symmetric comparison circuit includes a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, and a first operational amplifier a second operational amplifier and a second photocoupler; the sixth resistor is coupled to the forward input terminal of the first operational amplifier through the seventh resistor; the first resistor is coupled to the negative of the first operational amplifier through the ninth resistor An output terminal of the first operational amplifier is connected to a forward input terminal of the first operational amplifier through an eighth resistor; an output end of the first operational amplifier sequentially passes through the fourteenth resistor and the second photocoupler Accessing an output of the second operational amplifier; the sixth resistor is coupled to the forward input terminal of the second operational amplifier through the twelfth resistor; and the second resistor is coupled to the negative of the second operational amplifier through the eleventh resistor An output terminal of the second operational amplifier is connected to a forward input terminal of the second operational amplifier through a thirteenth resistor; the first resistor is passed through a tenth The resistor is connected to the eleventh resistor.

The brushless motor body comprises a slotless stator, a square wave permanent magnet rotor and a stator winding; the slotless stator is sleeved outside the square wave permanent magnet rotor; the stator winding is arranged in the slotless stator and the square wave permanent magnet The stator is fixed to the inner wall of the slotless stator; a gap is formed between the stator winding and the square wave permanent magnet rotor.

The stator winding includes an insulating bobbin and an armature conductor; the armature conductor is mounted on the insulating skeleton; and the insulating bobbin is fixed on the inner wall of the slotless stator.

The armature conductor is a wire having a rectangular cross section; the wire having the rectangular cross section is alternately embedded in the insulating frame.

The square wave permanent magnet rotor includes a spline tube shaft, a spline pole skeleton, a magnetic shoe and a permanent magnet; the spline pole skeleton is disposed outside the spline shaft by a spline; the permanent magnet is fixed by the magnetic shoe On the spline pole skeleton.

The permanent magnets are arranged on the magnetic shoe by a stepped trapezoidal permanent magnet in a radially inner large outer circumference, and are fixed by a magnetic shoe and a spline magnetic pole skeleton.

The brushless motor body further includes an air cooling device disposed on the square wave permanent magnet rotor; the air cooling device includes an external air cooling device and an internal air cooling device; the external air cooling device is disposed inside the spline shaft a venting tube parallel to the axial direction of the spline tube shaft; the internal air cooling device includes a slit disposed on the square wave permanent magnet rotor, and a thin portion disposed on the spline pole skeleton and penetrating the slit The slit is penetrated by a slit formed between the stator winding and the square wave permanent magnet rotor through the slit.

The advantages of the invention are:

The working principle and control method of the DC square wave slotless permanent magnet brushless motor of the six-phase position sensor without the position sensor provided by the invention mainly comprises that the controller controls the on and off of the stator windings of each phase according to the rotor position, thereby realizing the entry into the magnetic induction intensity reduction region. The winding phase is de-energized. When the de-energized winding phase is at the center of the magnetic pole junction, the adjacent adjacent phase is energized, and the incoming adjacent phase is de-energized, so that the six phases can completely eliminate the torque ripple problem. The invention solves the problem that the existing three-phase brushless motor without a position sensor reaches the positive center of the magnetic pole boundary from the non-energized winding, and that the commutation is delayed by 30° electrical angle, and it is difficult to accurately realize the commutation, and the brushless motor equivalent to the position sensor can be provided. The commutation effect; and the six phases completely eliminate the torque ripple; the integrated stator winding of the double-layer rectangular conductor reduces the air gap and has a simple structure; the stepped trapezoidal permanent magnet square wave permanent magnet rotor better realizes the square wave magnetic field, Better force effect, easy processing and material saving. Since the width of the magnetic induction intensity reduction region in the DC square wave permanent magnet brushless motor of the six-phase position sensorless sensor of the present invention is smaller than the phase winding width of the six-phase winding, the width of the permanent magnet N and S poles is larger than The air gap between the rotor and the stator is twice, and in the control mode of the present invention, the phase of the region where the magnetic induction is reduced and the phase close to or entering the region are not energized, and the phase completely leaving the region is turned on, thereby making the commutation The winding of the magnetic induction reduction area (the junction of the magnetic poles) is not energized, which avoids the influence of the area of the magnetic induction reduction on the torque stress, so that the relative rotational speed of the armature (stator winding) is a stable value, effectively avoiding the torque ripple. The generation of the position sensor and the reliability of the position sensor are avoided. DRAWINGS

1 is a circuit schematic diagram of a six-phase DC square wave permanent magnet brushless motor provided by the present invention; FIG. 2 is a timing diagram of a magnetic field and an excitation pulse, an armature voltage, and a signal feedback generated based on the present invention; Commutation timing diagram of the present invention;

Figure 4.1 is a schematic view showing the structure of a square wave permanent magnet rotor and a slotless stator used in the present invention; Fig. 4.2 is a partially enlarged schematic view showing the structure shown in A of Fig. 4.1;

Figure 5.1 is a cross-sectional structural view of a brushless motor provided by the present invention;

Figure 5.2 is a B-B phase view of Figure 5.1;

6 is a schematic view showing the overall structure of a brushless motor provided by the present invention;

among them:

1-no-slot stator; 2-magnet; 3-magnetic shoe; 4-spline magnetic pole skeleton; 5-insulating skeleton; 6-armature conductor; 7-slit; 8-slitary slit; 9-slit; 10-flower Key tube shaft; 11-square wave permanent magnet rotor.

detailed description

Referring to FIG. 1, the present invention provides a six-phase DC square wave permanent magnet brushless motor, which comprises a controller, a bootstrap winding drive circuit, and a non-energized winding inductance under an excitation pulse. The value detecting circuit group and the brushless motor body; the controller is respectively connected to the brushless motor body through the bootstrap winding driving circuit and the non-energized winding inductance value detecting circuit group under the excitation pulse.

The non-energized winding inductance value detecting circuit group under the excitation pulse comprises six sets of non-energized winding inductance value detecting circuits under the same excitation pulse; the non-energized winding inductance value detecting circuits under each group of excitation pulses respectively correspond to the brushless motor body .

The non-energized winding inductance value detecting circuit under the excitation pulse comprises a centering power source, an optocoupler isolation excitation pulse source, a first motor phase voltage clamping circuit, a second motor phase voltage clamping circuit and an armature inductance measuring symmetric comparison circuit; Medium power supply, optocoupler isolated excitation pulse source, first motor phase voltage clamp The circuit, the second motor phase voltage clamping circuit and the armature inductance measuring symmetric comparison circuit are sequentially connected in parallel; the controller is connected to the optocoupler to isolate the excitation pulse source; the first motor phase voltage clamping circuit and the second motor phase voltage clamping circuit are connected in parallel After the brushless motor body is connected.

As shown in Figure 1, Rl, R2, Dl, CI provide the centering power supply, Rl, R2 resistance values are equal; R3, Gl, R4, Tl, Τ2 are optocoupler isolated excitation pulse sources; D2, D3, R5 are motor phases Voltage clamp circuit, protection excitation pulse source circuit, R5 has inductance value measurement resistance function; R6, D4, D5 are motor phase voltage clamp circuit, protection armature inductor current symmetrical comparison circuit; armature inductance measurement symmetrical comparison circuit by R7, R8, R9, RIO, R11, R12, R13, R14, Al, A2, G2, R9, RIO, Rll provide the positive and negative comparison reference for the op amps A1 and A2, and the R9 and Rll resistors have equal resistance values. When the characterized voltage enters the central potential region, the optocoupler conducts a zero-crossing signal to the controller. The difference between the positive and negative excitation pulse end times and the time interval of the rising or falling edge of the zero-crossing signal reflects the non-energization. The distance from the winding to the centerline of the magnetic pole boundary is confirmed by the controller and an armature drive or commutation signal is issued.

The centering power source includes a power input end, a grounding end, a first resistor, a second resistor, a Zener diode, and a capacitor; the power input end is respectively connected to the Zener diode and the capacitor through the first resistor; the Zener diode and the capacitor are connected in parallel and pass through the first The second resistor is connected to the ground terminal;

The optocoupler isolation excitation pulse source comprises a first photocoupler, a third resistor, a fourth resistor, a first triode and a second triode; the third resistor is connected to the controller through the first optocoupler; the first resistor And sequentially connecting the second resistor through the fourth resistor and the first photocoupler; the first resistor sequentially passes through the first triode and the second triode to the second resistor; the first triode is connected in parallel with the fourth resistor; The second transistor is connected in parallel with the first photocoupler;

The first motor phase voltage clamping circuit includes a second diode, a third diode, and a fifth resistor; the fifth resistor is coupled to the first resistor through the second diode; and the fifth resistor is coupled to the third resistor The second resistors are connected; the fifth resistors are respectively connected to the first triodes and the second triodes;

The second motor phase voltage clamping circuit includes a sixth resistor, a fourth diode, and a fifth diode; one end of the sixth resistor is connected to the fifth resistor, and the other end is respectively connected to the fourth diode and the fifth diode The tube correspondingly connects the first resistor and the second resistor;

The armature inductance measuring symmetric comparison circuit includes a seventh resistor, an eighth resistor, a ninth resistor, and a tenth a resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a first operational amplifier, a second operational amplifier, and a second photocoupler; the sixth resistor is connected to the first operation through the seventh resistor a positive input terminal of the amplifier; the first resistor is connected to the negative input terminal of the first operational amplifier through the ninth resistor; the output terminal of the first operational amplifier is connected to the forward input terminal of the first operational amplifier through the eighth resistor; An output of the operational amplifier is sequentially connected to the output of the second operational amplifier through the fourteenth resistor and the second photocoupler; the sixth resistor is connected to the positive input terminal of the second operational amplifier through the twelfth resistor; The resistor is connected to the negative input terminal of the second operational amplifier through the eleventh resistor; the output terminal of the second operational amplifier is connected to the forward input terminal of the second operational amplifier through the thirteenth resistor; The eleventh resistor is connected.

Referring to FIG. 4.1, FIG. 4.2 and FIG. 6, in order to realize the square wave permanent magnet rotor and the slotless stator structure of the present invention, the stator winding adopts inner and outer double-layer rectangular wires, and is integrally fixed with the insulating skeleton to improve the armature wire cross section. The radial wave thickness is reduced; the square wave permanent magnet rotor adopts a stepped trapezoidal permanent magnet with a large outer circumference and a small outer circumference, so that the permanent magnet width at the outer diameter of the rotor is larger than the double air gap size, and the shortest path of the magnetic field line is worn. Through the stator winding, the magnetic flux leakage is reduced, and a more ideal square wave magnetic field is realized. The trapezoidal step of the permanent magnet is advantageously embedded, avoiding the wedge force, and the structure is simple. The positions of the plurality of permanent magnets are arranged side by side, the steps are completely coincident, the size head The edges are flush, and the rectangular magnetic steel can be used to save the material. The trapezoidal structure of the permanent magnets makes the permanent magnet pole intermediate magnetic circuit path length correspond to the thickness of the magnetic pole, which can improve the uniformity of the magnetic field. The stepped structure does not substantially damage the uniform magnetic field strength of the trapezoidal structure, and does not increase the processing workload excessively, but improves Arts and practicality.

Specifically, the brushless motor body includes a slotless stator 1, a square wave permanent magnet rotor 11 and a stator winding; the slotless stator 1 is sleeved outside the square wave permanent magnet rotor 11; the stator winding is disposed in the slotless stator 1 and the square wave The permanent magnet rotors 11 are fixed to the inner wall of the slotless stator 1; a gap 7 is provided between the stator windings and the square wave permanent magnet rotor 11.

The stator winding includes an insulating bobbin 5 and an armature conductor 6; the armature conductor 6 is mounted on the insulating bobbin 5; and the insulating bobbin 5 is fixed to the inner wall of the slotless stator 1. The armature conductor 6 is a wire having a rectangular cross section; a double-layered wire having a rectangular cross section is staggered and embedded on the insulating bobbin 5. The square wave permanent magnet rotor 11 includes a spline tube shaft 10, a spline pole skeleton 4, a magnetic shoe 3, and a permanent magnet 2; the spline pole skeleton 4 is disposed around the spline tube shaft 10 by splines; the permanent magnet 2 passes The magnetic shoe 3 is fixed to the spline pole skeleton 4. Permanent magnet 2 The stepped trapezoidal permanent magnet 2 is uniformly distributed on the magnetic shoe 3 in a radially inner large outer circumference, and is fixed to the spline magnetic pole skeleton 4 by the magnetic shoe 3.

Referring to Fig. 5.1 and Fig. 5.2, in order to realize the air cooling of the present invention, the permanent magnet rotor is designed with a two-way air cooling mode, one is a centrifugal inner circulation, and the other is an axial outer circulation. The inner circulation is when the rotor rotates, the wind is blown toward the stator winding by the centrifugal force of the narrow slit of the rotor, flows to the two end caps along the gap between the stator and the rotor, and is then sucked into the circulation hole of the rotor. The belt end cap and the spline tube shaft; the axial outer circulation is the external air circulation, which can reduce the temperature of the spline shaft, and independently circulate inside and outside, avoiding water, impurities and corrosive gases to the stator winding and the rotor forever. Destruction of magnets and insulators. In order to realize the spline magnetic pole skeleton of the present invention, as shown in FIG. 5, the spline magnetic pole skeleton and the spline tube shaft are spline-connected, so that the narrow slit processing of the spline magnetic pole skeleton can be simplified, and it is convenient to separately select a more suitable material. .

Specifically, the brushless motor body used in the present invention further includes an air cooling device disposed on the square wave permanent magnet rotor 11; the air cooling device includes an external air cooling device and an internal air cooling device; and the external air cooling device is disposed at a ventilating tube inside the spline tube shaft 10 in parallel with the axial direction of the spline tube shaft 10; the internal air cooling device includes a slit 8 disposed on the square wave permanent magnet rotor 11 and disposed on the spline pole skeleton 4 The slit 9 which penetrates the narrow slit 8; the slit 9 penetrates through the slit 7 and the slit 7 formed between the stator winding and the square wave permanent magnet rotor 11.

The present invention refers to the positive center of the magnetic pole junction of the permanent magnet rotor as the zero point, and the commutation timing of the six-phase stator winding is the same as the zero-crossing moment of the non-energized winding, and the exact control of the direct commutation without delaying the electrical angle of 30 degrees, and the motor speed Nothing.

The working principle and control method of the six-phase position sensorless DC square wave slotless permanent magnet brushless motor of the invention mainly comprises the controller controlling the on and off of the stator windings of each phase according to the rotor position, and realizing the winding entering the magnetic induction intensity reduction region. When the power-off winding phase is at the center of the magnetic pole junction, the adjacent adjacent phase is energized, and the incoming adjacent phase is powered off, so that the six phases can completely eliminate the torque ripple problem. The key to the invention is the inductance measurement circuit through the energized windings under the excitation pulse, an embodiment of which is shown in FIG. The controller determines the rotor position by aligning the armature inductances under positive and negative excitation pulses and provides armature drive control.

In order to achieve the control of the present invention, the present invention provides a six-phase bridge type control circuit, which is suitable for The control of the six-phase winding permanent magnet brushless DC motor, the circuit mainly comprises a controller, a bootstrap winding drive circuit, and a non-energized winding inductance value detecting circuit under the excitation pulse.

Since the width of the magnetic induction intensity reduction region in the DC square wave permanent magnet brushless motor of the six-phase position sensorless sensor of the present invention is smaller than the phase winding width of the six-phase winding, the width of the permanent magnet N and S poles is larger than the air gap between the rotor and the stator. Double, and in the control mode of the present invention, the phase of the magnetic induction reduction region and the phase close to or entering the region are not energized, and the phase completely leaving the region is turned on, thereby causing the commutation magnetic induction reduction region (magnetic pole junction) The winding of the electric power is not energized, which avoids the influence of the area of the magnetic induction reduction on the torque, so that the relative rotational speed of the armature (stator winding) is stable, effectively avoiding the generation of torque ripple and avoiding the position. Sensor reliability issues.

In order to realize the rotor position detection of the present invention, the magnetic field, the excitation pulse, the armature voltage, and the signal feedback timing diagram are as shown in FIG. From the end of the positive and negative excitation pulses A1 sent by the controller, the zero return time of the rising or falling edge of the received A2, the degree of consistency of the two periods is the distance of the rotor commutation time, and the time is equal. The commutation moment of zero. Here, the frequency and width of the excitation pulse can be flexibly adjusted by the controller software, and the determination of the rotor position is given by the control software in terms of time consistency. When the motor is stationary before starting, the rotor position is measured one by one by measuring the six-phase inductance, and the two phases that are completely at the zero point or the two phases that are not completely at the zero point and the two-phase quantitative position are obtained. This method is simple, precise, and flexible, and it is more accurate than the position sensor to measure the position of the rotor. This can be seen when the position of the rotor is measured before the start. This measurement method is similar to the rotor position measurement of the rotary transformer.

When the motor starts from stationary to increase in speed, the back electromotive force increases, and the back electromotive force of the non-energized winding is farther away from the zero position, and the excitation pulse signal is flooded. The back electromotive force of the non-energized winding is closer to the zero position. Small, the back electromotive force is zero when it reaches the zero position, and it does not affect the judgment of the rotor position commutation time. The commutation timing of the present invention is shown in FIG.

Claims

claims

1. A six-phase DC square wave permanent magnet brushless motor, characterized in that: the six-phase DC square wave permanent magnet brushless motor includes a controller, a bootstrap winding drive circuit, and a non-energized winding inductance value under excitation pulses Detection circuit group and brushless motor body; The controller is connected to the brushless motor body through a bootstrap winding drive circuit and a non-energized winding inductance value detection circuit group under excitation pulses.

2. The six-phase DC square wave permanent magnet brushless motor according to claim 1, characterized in that: the non-energized winding inductance value detection circuit group under the excitation pulse includes six groups of non-energized windings under the same excitation pulse. Inductance value detection circuit; The inductance value detection circuit of the non-energized winding under each group of excitation pulses is respectively connected to the brushless motor body.

3. The six-phase DC square wave permanent magnet brushless motor according to claim 2, characterized in that: the non-energized winding inductance value detection circuit under the excitation pulse includes a centering power supply, an optocoupler isolation excitation pulse source, and a third A motor phase voltage clamping circuit, a second motor phase voltage clamping circuit and an armature inductance measurement symmetry comparison circuit; the centering power supply, the optocoupler isolation excitation pulse source, the first motor phase voltage clamping circuit, the second motor The phase voltage clamp circuit and the armature inductance measurement symmetry comparison circuit are connected in parallel in sequence; the controller is connected to the optocoupler isolation excitation pulse source; the first motor phase voltage clamp circuit and the second motor phase voltage clamp circuit are connected in parallel. Connect to the brushless motor body.

4. The six-phase DC square wave permanent magnet brushless motor according to claim 3, characterized in that: the centering power supply includes a power input terminal, a ground terminal, a first resistor, a second resistor, a voltage regulator tube and a capacitor. ; The power input end is connected to the voltage stabilizing tube and the capacitor respectively through the first resistor; The voltage stabilizing tube and the capacitor are connected in parallel and connected to the ground terminal through the second resistor;

The optocoupler isolation excitation pulse source includes a first optocoupler, a third resistor, a fourth resistor, a first transistor and a second transistor; the third resistor is connected to the controller through the first optocoupler. ; The first resistor is connected to the second resistor through the fourth resistor and the first photocoupler in sequence; The first resistor is connected to the second resistor through the first triode and the second triode in sequence; A triode is connected in parallel with the fourth resistor; the second triode is connected in parallel with the first photocoupler;

The first motor phase voltage clamping circuit includes a second diode, a third diode and a fifth resistor; the fifth resistor is connected to the first resistor through the second diode; the fifth resistor passes through The third diode is connected to the second resistor; the fifth resistor is connected to the first triode and the second triode respectively; The second motor phase voltage clamping circuit includes a sixth resistor, a fourth diode and a fifth diode; one end of the sixth resistor is connected to the fifth resistor, and the other end is connected to the fourth diode and the fifth diode respectively. The fifth diode is connected to the first resistor and the second resistor;

The armature inductance measurement symmetry comparison circuit includes a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, and a first operational amplifier , a second operational amplifier and a second optocoupler; the sixth resistor is connected to the positive input terminal of the first operational amplifier through a seventh resistor; the first resistor is connected to the negative input terminal of the first operational amplifier through a ninth resistor to the input end; the output end of the first operational amplifier is connected to the forward input end of the first operational amplifier through the eighth resistor; the output end of the first operational amplifier passes through the fourteenth resistor and the second photocoupler in sequence Connected to the output terminal of the second operational amplifier; The sixth resistor is connected to the positive input terminal of the second operational amplifier through the twelfth resistor; The second resistor is connected to the negative input terminal of the second operational amplifier through the eleventh resistor. The forward input end; the output end of the second operational amplifier is connected to the forward input end of the second operational amplifier through a thirteenth resistor; the first resistor is connected to the eleventh resistor through a tenth resistor.

5. The six-phase DC square wave permanent magnet brushless motor according to any one of claims 1 to 4, characterized in that: the brushless motor body includes a slotless stator, a square wave permanent magnet rotor and a stator winding; The slotless stator is sleeved on the outside of the square wave permanent magnet rotor; the stator winding is arranged between the slotless stator and the square wave permanent magnet rotor and is fixed on the inner wall of the slotless stator; the stator winding is connected to the square wave permanent magnet rotor. There are gaps between the magnetic rotors.

6. The six-phase DC square wave permanent magnet brushless motor according to claim 5, characterized in that: the stator winding includes an insulating skeleton and an armature conductor; the armature conductor is embedded in the insulating skeleton; the insulation The skeleton is fixed to the inner wall of the slotless stator.

7. The six-phase DC square wave permanent magnet brushless motor according to claim 6, characterized in that: the armature conductor is a conductor with a rectangular cross-section; the conductors with a rectangular cross-section are double-layered and interlaced in an insulating frame. superior.

8. The six-phase DC square wave permanent magnet brushless motor according to claim 7, characterized in that: the square wave permanent magnet rotor includes a splined tube shaft, a splined magnetic pole frame, a magnetic shoe and a permanent magnet; The splined magnetic pole frame is arranged on the outside of the splined tube shaft through splines; the permanent magnet is fixed on the splined tube shaft through magnetic shoes. Splined magnetic pole frame.

9. The six-phase DC square wave permanent magnet brushless motor according to claim 8, characterized in that: the permanent magnet adopts a stepped trapezoidal permanent magnet, and is evenly distributed on the magnetic shoe in the radial direction, with a large diameter on the inside and a small diameter on the outside. The boots are fixed to the splined magnetic pole frame.

10. The six-phase DC square wave permanent magnet brushless motor according to claim 9, characterized in that: the brushless motor body further includes an air cooling device provided on the square wave permanent magnet rotor; the air cooling device It includes an external air cooling device and an internal air cooling device; the external air cooling device is a ventilation pipe arranged inside the spline tube shaft and parallel to the axial direction of the spline tube axis; the internal air cooling device includes a ventilation pipe arranged in the square The narrow slits on the wave permanent magnet rotor and the narrow slits provided on the splined magnetic pole frame and connected with the narrow slits; the narrow slits communicate with the gaps formed between the stator windings and the square wave permanent magnet rotor through the narrow slits. Through.