CN110707985A

CN110707985A - Motor capable of realizing multi-stage speed change

Info

Publication number: CN110707985A
Application number: CN201911130973.6A
Authority: CN
Inventors: 郭鹏超
Original assignee: Xiamen Ruiduo Electronic Technology Co Ltd
Current assignee: Chen Yubing
Priority date: 2019-11-19
Filing date: 2019-11-19
Publication date: 2020-01-17

Abstract

The invention discloses a multistage variable speed motor, which comprises a rotor, a stator, a control chip, at least two coils and a corresponding number of control switches, wherein each coil is independently and electrically connected with one control switch, each control switch is respectively and electrically connected with the control chip, the control chip respectively controls the forward or reverse conduction of each control switch so as to control the current direction of the coil, so that N-pole magnetic poles or S-pole magnetic poles of the motor are respectively formed between the coils, and the control chips conduct the control switches in groups at different time sequences so as to control the N-pole magnetic poles and the S-pole magnetic poles of the motor to be arranged and combined at intervals to carry out the grade change of the motor. The invention adopts an independent control mode of each coil, can change the pole, and can control the positive and negative rotation and the phase of the motor, thereby finally obtaining the motor with multi-stage speed change and high efficiency.

Description

Motor capable of realizing multi-stage speed change

Technical Field

The invention relates to the field of motors, in particular to a multi-stage variable speed motor.

Background

With the popularization of new energy automobiles and the large use of electric driven automobiles, the motor has quite wide application prospect as an important component of the automobiles. However, during the low-speed operation and high-speed operation of the motor, the problem of low efficiency often occurs, so that the rotating speed of the motor is not stable, and even the motor sometimes stops rotating.

For example, as shown in fig. 1, a two-speed motor disclosed in patent No. 201720353577.X is configured such that a motor controller of the related art controls a switch K1ab, a switch K1bc and a switch K1ac to be turned on, and other switches are turned off, at this time, a coil AA2, a coil A3B, a coil BB2, a coil B3C, a coil CC2 and a coil C3A are connected in series, and at this time, the motor is in a low-speed high-torque operating state, which is suitable for low-speed operation of a vehicle. When the high-speed operation of the motor is required, the motor controller controls the switch K1ab, the switch K1bc and the switch K1ac to be switched off, and simultaneously controls the switch K2ba, the switch K2ab, the switch K2bc, the switch K2cb, the switch K2ac and the switch K2ca to be switched on, at the moment, the coil AA2, the coil A3B, the coil BB2, the coil B3C, the coil CC2 and the coil C3A are in a state that two coils are connected in parallel and three groups of coils are connected in series, and at the moment, the motor operates at a high speed and is suitable for the high-speed operation of a vehicle. It can thus be seen that: (1) in the prior art, low-speed and high-speed pole changing is realized by changing the serial connection state and the parallel connection state among coil groups, and moreover, the low-speed and high-speed pole changing has and only has two pole changing states; (2) when the voltage is unchanged, the internal resistance of the coil is constant, and the series resistance is four times of the parallel resistance through calculation, so that the total power of the motor under two working conditions is greatly different, and the power factor is greatly different according to the principle of the motor, and the efficiency is greatly different.

Disclosure of Invention

The invention aims to provide a motor capable of realizing multi-stage speed change, which solves the efficiency problem of the motor at different rotating speeds, has the characteristics of multi-stage speed change and high efficiency and ensures that the motor runs stably.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a motor capable of changing speed in multiple stages comprises a rotor, a stator, control chips, coils with more than two slots and control switches with corresponding quantity, wherein each coil is electrically connected with one control switch independently, each control switch is electrically connected with the control chips respectively, the control chips control the forward or reverse conduction of each control switch respectively so as to control the current direction of the coils, so that N-pole magnetic poles or S-pole magnetic poles of the motor are formed between the coils respectively, and the control chips conduct the control switches in groups in different time sequences so as to control the N-pole magnetic poles and the S-pole magnetic poles of the motor to be arranged and combined at intervals to carry out the stage change of the motor.

The number of the coils is N grooves, N is an even number and is L respectively₁、L₂、……、L_NN control switches are also provided, and are respectively Q₁、Q₂、……、Q_NThe coil and the control switch are equally divided into two groups, and the control chip divides one group of control switch Q₁-Q_N/2Is conducted in the forward direction toTo obtain L₁-L_N/2The coil is a positive current to form an N-pole magnetic pole of the motor, and the control chip controls the other set of control switches Q_N/2+1-Q_NReverse conduction to make L_N/2+1-L_NThe coil is an S-pole magnetic pole of the motor formed by reverse current, and the motor is two-pole at the moment, rotates forwards and has the highest rotating speed.

The number of the coils is N grooves, N is an even number and is L respectively₁、L₂、……、L_NN control switches are also provided, and are respectively Q₁、Q₂、……、Q_NThe coil and the control switch are equally divided into two groups, and the control chip divides one group of control switch Q₁-Q_N/2Reverse conduction to make L₁-L_N/2The coil is reverse current to form S pole of motor, and the control chip controls another set of switch Q_N/2+1-Q_NForward direction conduction, so that L_N/2+1-L_NThe coil is a positive current to form an N-pole magnetic pole of the motor, the motor is two poles at the moment, the motor rotates reversely, and the rotating speed is highest.

The number of the coils is N grooves, N is an even number and is L respectively₁、L₂、……、L_NN control switches are also provided, and are respectively Q₁、Q₂、……、Q_NThe coils and the control switches are divided into N/2 groups, and the control chip controls the odd control switches Q of each group₁、Q₃、……、Q_N-1Forward direction conduction, so that L₁、L₃、……、L_N-1The coil forms N-pole magnetic pole of the motor for positive current, and the control chip switches the even number of control switches Q of each group₂、Q₄、……、Q_NReverse conduction to make L₂、L₄、……、L_NThe coil is an S pole of the motor formed by reverse current, and the motor is N/2 pole at the moment and has the lowest rotating speed.

The number of the coils is 12, and the coils are L respectively₁、L₂、……、L₁₂The number of the control switches is also 12, and the control switches are respectively Q₁、Q₂、……、Q₁₂The coil and the control switch are equally divided into two groups, and the control chip divides one group of control switch Q₁-Q₆Forward direction conduction, so that L₁-L₆The coil is a positive current to form an N-pole magnetic pole of the motor, and the control chip controls the other set of control switches Q₇-Q₁₂Reverse conduction to make L₇-L₁₂The coil is an S-pole magnetic pole of the motor formed by reverse current, and the motor is two-pole at the moment and has the highest rotating speed.

The number of the coils is 12, and the coils are L respectively₁、L₂、……、L₁₂The number of the control switches is also 12, and the control switches are respectively Q₁、Q₂、……、Q₁₂The coils and the control switches are divided into six groups in an equal way, and the control chip divides the odd control switches Q of each group₁、Q₃、……、Q₁₁Forward direction conduction, so that L₁、L₃、……、L₁₁The coil forms N pole of the motor for positive current, and the control chip switches the odd-numbered and even-numbered control switches Q of each group₂、Q₄、……、Q₁₂Reverse conduction to make L₂、L₄、……、L₁₂The coil is an S-pole magnetic pole of the motor formed by reverse current, and the motor is six-pole and has the lowest rotating speed.

The number of the coils is 12, and the coils are L respectively₁、L₂、……、L₁₂The number of the control switches is also 12, and the control switches are respectively Q₁、Q₂、……、Q₁₂The coils and the control switches are equally divided into four groups, and the control chip divides the control switch Q of the first group into four groups₁-Q₃Forward direction conduction, so that L₁-L₃The coil forms N pole of the motor for positive current, and the control chip switches Q of the second group₄-Q₆Reverse conduction to make L₄-L₆The coil forms S pole of motor for reverse current, and the control chip switches Q of the third group₇-Q₉Forward direction conduction, so that L₇-L₉The coil forms N-pole magnetic pole of the motor for positive current, and the control chip controls the control switch Q of the fourth group₁₀-Q₁₂Reverse conduction to make L₁₀-L₁₂The coil is reverse current to form S pole of motor, and the motor is four poles。

The control chip controls the current of the coils between the two adjacent groups to have phase difference.

And a vacant cavity is formed in the center of the stator and is used for installing a control chip and a control switch.

Compared with the prior art, the invention only can realize two kinds of pole changes, namely fast pole change and slow pole change, by adopting the coil series connection and parallel connection modes, when the voltage is not changed, the internal resistance of the coil is constant, the series resistance is 4 times of the parallel resistance, the total power during working is also greatly different, and the efficiency is also greatly different according to the power factors under two working conditions of the motor principle. The invention adopts an independent control mode of each coil, each coil loop is connected in parallel without influencing the whole power when changing, the more slots are, the more poles can be changed, and the positive and negative rotation and the phase of the motor can be controlled. Therefore, the difference of the whole power of the motor is small when the pole is changed, the pole changing efficiency is improved, and the motor with multi-stage speed change and high efficiency is obtained finally.

Drawings

FIG. 1 is an electrical schematic of the prior art;

FIG. 2 is an electrical schematic of the present invention;

fig. 3 is a schematic view of the structure of the motor of the present invention.

Detailed Description

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other technical solutions can be obtained according to the drawings without creative efforts.

As shown in fig. 2 and 3, a multi-speed variable motor includes a rotor 1, a stator 2, control chips 3, even number slot coils L and a corresponding number of control switches Q, wherein each coil L is individually electrically connected to one control switch Q, each control switch Q is electrically connected to the control chip 3, the control chips 3 respectively control each control switch Q to be conducted in a forward or reverse direction to control a current direction of the coil L, so that N-pole magnetic poles or S-pole magnetic poles of the motor are formed between the coils L, and the control chips 3 conduct the control switches Q in groups at different time sequences to control the N-pole magnetic poles and S-pole magnetic poles of the motor to be arranged at intervals and combined for motor speed change.

In the first step-changing mode of the motor, the number of the coils is N slots, N is an even number and is an even multiple of 2, and L is respectively₁、_L2、……、L_NN control switches are also provided, and are respectively Q₁、Q₂、……、Q_NThe coil L and the control switch Q are equally divided into two groups, and the control chip divides one group of control switch Q into two groups₁-Q_N/2Forward direction conduction, so that L₁-L_N/2The coil is a positive current to form an N-pole magnetic pole of the motor, and the control chip controls the other set of control switches Q_N/2+1-Q_NReverse conduction to make L_N/2+1-L_NThe coil is an S-pole magnetic pole of the motor formed by reverse current, and the motor is two-pole at the moment and has the highest rotating speed. As shown in FIG. 2, the number of the coils L is 12, L₁、L₂、……、L₁₂The number of the control switches Q is also 12, and Q is respectively₁、Q₂、……、Q₁₂The coil L and the control switch Q are equally divided into two groups, and the coil L₁-L₆And control switch Q₁-Q₆In a set, coils L₇-L₁₂And control switch Q₇-Q₁₂For another group, control switch Q₁With two pins A₁₁、A₁₂Four MOS tube switches Q₁₁、Q₁₂、Q₁₃、Q₁₄Wherein Q is₁₁、Q₁₂Are respectively connected to the coil L₁One end of, Q₁₃、Q₁₄Are respectively connected to the coil L₁The other end of (1), wherein pin A₁₁Switch Q for connecting MOS tube₁₁、Q₁₄G pole of (1), pin A₁₂Switch Q for connecting MOS tube₁₃、Q₁₂G pole of (1), pin A₁₁、A₁₂Respectively connected with pins A of the control chip 3₀₁₁、A₀₁₂Similarly, the other control switches Q, the coil L, and the control chip 3 are electrically connected in the same manner. When controlling the coreChip 3 switch-on control switch Q₁Pin A of₁₁For MOS tube switch Q₁₁、Q₁₄When the G pole of the MOS tube is applied with voltage, the MOS tube switches Q₁₁、Q₁₄On, current slave MOS transistor switch Q₁₁Warp coil L₁To MOS transistor switch Q₁₄Is called a control switch Q₁Is positively conducted, coil L₁Forming N pole of the motor, and turning on the control switch Q when the control chip 3₂Pin A of₂₁For MOS tube switch Q₂₁、Q₂₄When the G pole of the MOS tube is applied with voltage, the MOS tube switches Q₂₁、Q₂₄On, current slave MOS transistor switch Q₂₁Warp coil L₂To MOS transistor switch Q₂₄To control the switch Q₂Is positively conducted, coil L₂Forming N pole of motor, and controlling switch Q₃、Q₄、Q₅、Q₆Is positively conducted, coil L₃、L₄、L₅、L₆Forming N-poles of the machine, i.e. coils L₁-L₆All form the N pole of the motor in the same direction, and when the control chip 3 is switched on, the other group controls the switch Q₇Pin A of₇₂For MOS tube switch Q₇₃、Q₇₂When the G pole of the MOS tube is applied with voltage, the MOS tube switches Q₇₃、Q₇₂On, current slave MOS transistor switch Q₇₃Warp coil L₇To MOS transistor switch Q₇₂Is called a control switch Q₇Is reversely conducted, coil L₇Forming S pole of the motor, and turning on the control switch Q when the control chip 3₈Pin A of₈₂For MOS tube switch Q₈₃、Q₈₂When the G pole of the MOS tube is applied with voltage, the MOS tube switches Q₈₃、Q₈₂On, current slave MOS transistor switch Q₈₃Warp coil L₈To MOS transistor switch Q₈₂To control the switch Q₈Is reversely conducted, coil L₈Form S pole of motor, and control switch Q₉、Q₁₀、Q₁₁、Q₁₂Is reversely conducted, coil L₉、L₁₀、L₁₁、L₁₂All form S pole of the motor in the same directionThe motor has two poles, rotates forwards and has the highest rotating speed.

On the contrary, when the control chip 3 turns on the control switch Q₁-Q₆Pin A of₁₂-A₆₂For MOS transistor switch (Q)₁₃、Q₁₂)、(Q₂₃、Q₂₂)、……、(Q₆₃、Q₆₂) When a voltage is applied to the G pole, the MOS tube switches (Q)₁₃、Q₁₂)、(Q₂₃、Q₂₂)、……、(Q₆₃、Q₆₂) On, current slave MOS transistor switch Q₁₃Warp coil L₁To MOS transistor switch Q₁₂Flows in the direction of (1), the current is switched from MOS tube to Q₂₃Warp coil L₂To MOS transistor switch Q₂₂Flows in the same direction, and so on, controls the switch Q₁-Q₆Is reversely conducted, coil L₁-L₆All form S pole of the motor in the same direction, and the other group is provided with a control chip 3 which is connected with a control switch Q₇-Q₁₂Pin A of₇₁-A₁₂₁For MOS transistor switch (Q)₇₁、Q₇₄)、(Q₈₁、Q₈₄)、……、(Q₁₂₁、Q₁₂₄) When a voltage is applied to the G pole, the MOS tube switches (Q)₇₁、Q₇₄)、(Q₈₁、Q₈₄)、……、(Q₁₂₁、Q₁₂₄) On, current slave MOS transistor switch Q₇₁Warp coil L₇To MOS transistor switch Q₇₄Flows in the direction of (1), the current is switched from MOS tube to Q₈₁Warp coil L₈To MOS transistor switch Q₈₄Flows in the same direction, and so on, controls the switch Q₇-Q₁₂Is positively conducted, coil L₇-L₁₂The magnetic poles of S poles of the motor are formed in the same direction, and the motor is dipolar and rotates reversely at the highest rotating speed.

In the second stage-changing mode of the motor, the number of the coils L is N grooves, N is an even number and is an even multiple of 2, and the number of the coils L is L₁、L₂、……、L_NThe number of the control switches Q is also N, and the control switches Q are respectively Q₁、Q₂、……、Q_NThe coil L and the control switch Q are equally divided into N/2 groups, and the control chip divides the odd control switches Q of each group₁、Q₃、……、Q_N-1Forward direction conduction, so that L₁、L₃、……、L_N-1The coils form N-pole magnetic poles of the motor, and the control chip switches the even number of control switches Q of each group₂、Q₄、……、Q_NReverse conduction to make L₂、L₄、……、L_NThe coil forms a motor and an S pole magnetic pole for reverse current, and the motor is N/2 pole at the moment and has the lowest rotating speed. As shown in FIGS. 2 and 3, the number of the coils is 12, L₁、L₂、……、L₁₂The number of the control switches is also 12, and the control switches are respectively Q₁、Q₂、……、Q₁₂Dividing the coil L and the control switch Q into six groups equally, wherein the coil L₁-L₂And control switch Q₁-Q₂Is a first group, a coil L₃-L₄And control switch Q₃-Q₄Is a second group, and so on, and the coil L₁₁-L₁₂And control switch Q₁₁-Q₁₂For the sixth group, the control chip 3 switches on the odd control switches Q of each group₁、Q₃、……、Q₁₁Pin A of₁₁-A₃₁For MOS transistor switch (Q)₁₁、Q₁₄)、(Q₃₁、Q₃₄)……、(Q₁₁₁、Q₁₁₄) Pressurizing forward to conduct L₁、L₃、……、L₁₁The coils form a motor and an N-pole magnetic pole for positive current, and the control chip 3 is connected with the even control switches Q of each group₂、Q₄、……、Q₁₂Pin A of₂₂、A₄₂……、Q₁₂₂MOS transistor switch (Q)₂₃、Q₂₂)、(Q₄₃、Q₄₂)……、(Q₁₂₃、Q₁₂₂) Pressurized reverse conduction to L₂、L₄、……、L₁₂The coil is an S-pole magnetic pole of the motor formed by reverse current, and the motor is six-pole at the lowest rotating speed.

In the third step-changing mode of the motor of the invention, as shown in fig. 2, the number of the coils L is 12, and the coils L are L respectively₁、L₂、……、L₁₂The number of the control switches Q is also 12, and Q is respectively₁、Q₂、……、Q₁₂The coil L and the control switch Q are equally divided into four groups, and the coil L₁-L₃And control switch Q₁-Q₃Is a first group, a coil L₄-L₆And control switch Q₄-Q₆Is a second group, and so on, and the coil L₁₀-L₁₂And control switch Q₁₀-Q₁₂For the fourth group, the control chip 3 switches on the control switch Q of the first group₁-Q₃Pin A of₁₁、A₂₁Q31 to MOS transistor switch (Q)₁₁、Q₁₄)、(Q₂₁、Q₂₄)、(Q₃₁、Q₄₄) Pressurizing forward to conduct L₁-L₃The coil forms N pole of the motor for positive current, and the control chip 3 is connected with the control switch Q of the second group₄-Q₆Pin A of₄₂、A₅₂、Q₆₂For MOS transistor switch (Q)₄₃、Q₄₂)、(Q₅₃、Q₅₂)、(Q₆₃、Q₆₂) Reverse conduction to make L₄-L₆The coil forms S pole of motor for reverse current, and the control chip 3 is connected with the control switch Q of the third group₇-Q₉Pin A of₇₁、A₈₁、Q₉₁For MOS transistor switch (Q)₇₁、Q₁₄)、(Q₈₁、Q₈₄)、(Q₉₁、Q₉₄) Pressurizing forward to conduct L₇-L₉The coil forms N pole of the motor for positive current, the control chip 3 is connected with the control switch Q of the adjacent fourth group₁₀-Q₁₂Pin A of₁₀₂、A₁₁₂、Q₁₂₂For MOS transistor switch (Q)₁₀₃、Q₁₀₂)、(Q₁₁₃、Q₁₁₂)、(Q₁₂₃、Q₁₂₂) Pressurized reverse conduction to L₁₀-L₁The coil 2 is an S pole of the motor formed by reverse current, and the motor is four poles at the moment and has medium rotating speed.

In the above-described embodiment, in order to make the N-pole magnetic pole and the S-pole magnetic pole of the motor appear in pairs, the number of groups of the coils L and the control switches Q is an even number, and indeed, the number of the coils L and the corresponding number of the control switches Q in the present application is not necessarily an even number, but may also be an odd number, and the number of groups of the groups may also be an odd number, because each coil L in the present application adopts an independent control mode, the control chip can singly control some control switches Q not to be turned on, the coils L do not work, some groups do not work, or current with phase difference is input between different groups between different coils L.

As shown in fig. 3, the center of the stator 2 is provided with a vacant cavity for the control chip and the control switch Q₁、Q₂、……、Q₁₂And (4) installing.

The foregoing shows and describes the general principles and features of the present invention, together with the advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. A multi-speed variable motor is characterized in that: the motor comprises a rotor, a stator, a control chip, coils with more than two grooves and control switches with corresponding quantity, wherein each coil is electrically connected with one control switch independently, each control switch is electrically connected with the control chip respectively, the control chip controls the forward or reverse conduction of each control switch respectively so as to control the current direction of the coils, so that N-pole magnetic poles or S-pole magnetic poles of the motor are formed between the coils respectively, and the control switches are conducted in groups with different time sequences so as to control the N-pole magnetic poles and the S-pole magnetic poles of the motor to be arranged and combined at intervals to carry out motor level change.

2. A multi-speed variable electric motor as claimed in claim 1, wherein: the number of the coils is N grooves, N is an even number and is L respectively₁、L₂、……、L_NN control switches are also provided, and are respectively Q₁、Q₂、……、Q_NThe coil and the control switch are equally divided into two groups, and the control chip divides one group of control switch Q₁-Q_N/2Forward direction conduction, so that L₁-L_N/2The coil is a positive current to form an N-pole magnetic pole of the motor, and the control chip controls the other set of control switches Q_N/2+1-Q_NReverse conduction to make L_N/2+1-L_NThe coil is an S-pole magnetic pole of the motor formed by reverse current, and the motor is two-pole at the moment, rotates forwards and has the highest rotating speed.

3. A multi-speed variable electric motor as claimed in claim 1, wherein: the number of the coils is N grooves, N is an even number and is L respectively₁、L₂、……、L_NN control switches are also provided, and are respectively Q₁、Q₂、……、Q_NThe coil and the control switch are equally divided into two groups, and the control chip divides one group of control switch Q₁-Q_N/2Reverse conduction to make L₁-L_N/2The coil is reverse current to form S pole of motor, and the control chip controls another set of switch Q_N/2+1-Q_NForward direction conduction, so that L_N/2+1-L_NThe coil is a positive current to form an N-pole magnetic pole of the motor, the motor is two poles at the moment, the motor rotates reversely, and the rotating speed is highest.

4. A multi-speed variable electric motor as claimed in claim 1, wherein: the number of the coils is N grooves, N is an even number and is L respectively₁、L₂、……、L_NN control switches are also provided, and are respectively Q₁、Q₂、……、Q_NThe coils and the control switches are divided into N/2 groups, and the control chip controls the odd control switches Q of each group₁、Q₃、……、Q_N-1Forward direction conduction, so that L₁、L₃、……、L_N-1The coil forms N-pole magnetic pole of the motor for positive current, and the control chip switches the even number of control switches Q of each group₂、Q₄、……、Q_NReverse conduction to make L₂、L₄、……、L_NThe coil is an S pole of the motor formed by reverse current, and the motor is N/2 pole at the moment and has the lowest rotating speed.

5. A multi-speed variable electric motor as claimed in claim 1, wherein: the number of the coils is 12, and the coils are L respectively₁、L₂、……、L₁₂The number of the control switches is also 12, and the control switches are respectively Q₁、Q₂、……、Q₁₂The coil and the control switch are equally divided into two groups, and the control chip divides one group of control switch Q₁-Q₆Forward direction conduction, so that L₁-L₆The coil is a positive current to form an N-pole magnetic pole of the motor, and the control chip controls the other set of control switches Q₇-Q₁₂Reverse conduction to make L₇-L₁₂The coil is an S-pole magnetic pole of the motor formed by reverse current, and the motor is two-pole at the moment and has the highest rotating speed.

6. A multi-speed variable electric motor as claimed in claim 1, wherein: the number of the coils is 12, and the coils are L respectively₁、L₂、……、L₁₂The number of the control switches is also 12, and the control switches are respectively Q₁、Q₂、……、Q₁₂The coils and the control switches are divided into six groups in an equal way, and the control chip divides the odd control switches Q of each group₁、Q₃、……、Q₁₁Forward direction conduction, so that L₁、L₃、……、L₁₁The coil forms N pole of the motor for positive current, and the control chip switches the odd-numbered and even-numbered control switches Q of each group₂、Q₄、……、Q₁₂Reverse conduction to make L₂、L₄、……、L₁₂The coil is an S-pole magnetic pole of the motor formed by reverse current, and the motor is six-pole and has the lowest rotating speed.

7. A multi-speed variable electric motor as claimed in claim 1, wherein: the number of the coils is 12, and the coils are L respectively₁、L₂、……、L₁₂Said control switchAlso 12, are respectively Q₁、Q₂、……、Q₁₂The coils and the control switches are equally divided into four groups, and the control chip divides the control switch Q of the first group into four groups₁-Q₃Forward direction conduction, so that L₁-L₃The coil forms N pole of the motor for positive current, and the control chip switches Q of the second group₄-Q₆Reverse conduction to make L₄-L₆The coil forms S pole of motor for reverse current, and the control chip switches Q of the third group₇-Q₉Forward direction conduction, so that L₇-L₉The coil forms N-pole magnetic pole of the motor for positive current, and the control chip controls the control switch Q of the fourth group₁₀-Q₁₂Reverse conduction to make L₁₀-L₁₂The coil is an S-pole magnetic pole of the motor formed by reverse current, and the motor is a quadrupole.

8. A multi-speed variable electric motor as claimed in claim 1, wherein: the control chip controls the current of the coils between the two adjacent groups to have phase difference.

9. A multi-speed variable electric motor as claimed in claim 1, wherein: and a vacant cavity is formed in the center of the stator and is used for installing a control chip and a control switch.