CN105207384B - A kind of double winding high power density composite excitation permanent magnet motor - Google Patents

Abstract

The invention discloses a double-winding high power density hybrid excitation permanent magnet motor, which includes a stator and a rotor. The stator includes a stator yoke composed of a stator slot yoke and a stator back yoke. There are permanent magnets, the stator slot yoke is located at the bottom of the stator slot close to the outer circumferential direction, the stator slot includes the slot where the armature winding is located, that is, the armature slot, and the slot where the excitation winding is located, that is, the excitation slot, and the armature slot and the excitation slot are along the circumference Alternately arranged at intervals, a set of armature windings is placed in the armature slot, and a set of excitation windings is placed in the excitation slot; the motor of the present invention saves material consumption and reduces costs.

Description

A Double Winding High Power Density Hybrid Excitation Permanent Magnet Motor

technical field

The invention relates to a permanent magnet motor, in particular to a double winding high power density hybrid excitation permanent magnet motor.

Background technique

In recent years, with the improvement of high temperature resistance and price reduction of permanent magnet materials, permanent magnet motors have been more widely used in national defense, industrial and agricultural production, and daily life, and are moving towards high power, high performance and miniaturization. direction of development. At present, the power of permanent magnet motors ranges from a few milliwatts to several thousand kilowatts, and its application ranges from toy motors, industrial applications to large permanent magnet motors for ship traction, and has been widely used in various aspects of the national economy, daily life, military industry, and aerospace. widely used. The main applications are as follows:

(1) Household appliances: including TV audio-visual equipment, fans, air conditioners, food processors, beauty tools, range hoods, etc.

(2) The field of computer and its peripheral equipment: including computers (drivers, fans, etc.), printers, plotters, CD-ROM drives, CD recorders, etc.

(3) Industrial production field: including industrial drive devices, material processing systems, automation equipment, robots, etc.

(4) Automotive field: including permanent magnet starters, wiper motors, door lock motors, seat lift motors, sunshade motors, washer pump motors, tape recorder motors, glass lift motors, radiator cooling fan motors, air conditioner motors, antennas Lifting motor, oil pump motor, etc.

(5) Public life field: including clocks and watches, beauty machines, vending machines, ATMs, money counters, etc.

(6) Transportation field: including trams, aircraft auxiliary equipment, ships, etc.

(7) Aerospace field: including rockets, satellites, spacecraft, space shuttles, etc.

(8) National defense field: including tanks, missiles, submarines, aircraft, etc.

(9) Medical field: including dental drills, artificial hearts, medical devices, etc.

(10) Power generation field: including wind power generation, waste heat power generation, small hydropower generation, generators for small internal combustion generator sets, and auxiliary exciters for large generators.

Conventional AC permanent magnet motors are usually divided into the following categories: asynchronous start permanent magnet synchronous motors, permanent magnet brushless DC motors, and speed-adjustable permanent magnet synchronous motors.

The brushless DC motor and the variable speed permanent magnet synchronous motor are basically the same in structure, with multi-phase windings on the stator and permanent magnets on the rotor. The main difference between them is that the brushless DC motor realizes self-synchronization according to the rotor position information. Their advantages are: (1) the brush commutator is eliminated, and the reliability is improved; (2) the loss is mainly generated by the stator, and the heat dissipation condition is good; (3) the volume is small and the weight is light.

The structural difference between the asynchronous start permanent magnet synchronous motor and the variable speed permanent magnet synchronous motor is that the former has a starting winding or an integral iron core with a starting effect on the rotor, which can realize self-starting and can be connected to the grid without a control system.

In addition, there are single-phase permanent magnet motors. Single-phase permanent magnet motors need to be started and operated with supporting capacitors, which are bulky, high in cost, and have low overall operating efficiency and power factor.

The technical shortcomings of existing permanent magnet motors are as follows:

1. Due to the fixed magnetomotive force of the permanent magnet in the existing permanent magnet motor, the main magnetic flux of the motor is not adjustable, resulting in a narrow constant power operating range and a wide range of speed regulation. In addition, the motor winding is generally 3 phases, the number of stator slots is large, and the lower winding The line process is complicated.

2. The permanent magnets of most existing permanent magnet motors are located on the rotor and rotate with the rotor during operation. The permanent magnets need to be fixed by special procedures, and the manufacturing cost is high. Especially when the motor speed is high, it is more difficult to fix the permanent magnets. Located on the rotor, it is difficult to dissipate heat during operation. The temperature rise and the vibration caused by the rotation of the rotor will cause damage to the permanent magnet mechanical structure and irreversible demagnetization.

3. Existing permanent magnet motors are generally three-phase, and the power inverter circuit of the motor requires at least 6 power switching devices, such as IGBT or MOSFET, as well as the corresponding driving circuit and protection circuit for driving the power switching device. The cost of the motor power inverter circuit is quite high, even reaching two to three times the cost of the motor body. The increase in the number of power switching devices increases the complexity of the control circuit, increases the possibility of device failure, and reduces the reliability of the system during operation.

In view of the shortcomings of existing permanent magnet motors that the excitation magnetic potential cannot be adjusted, relevant scholars have proposed some hybrid excitation structure motors. This type of hybrid excitation structure motors can be divided into two categories in terms of excitation methods:

One is the series structure of permanent magnet magnetic potential and excitation winding magnetic potential. Since the excitation flux needs to pass through the permanent magnet, the excitation current is large, the excitation loss is high, and the risk of irreversible demagnetization will occur to the permanent magnet. widely;

The other type is a structure in which the magnetic potential of the permanent magnet and the magnetic potential of the excitation winding are connected in parallel. This type of structure generally adopts the stator permanent magnet type. The permanent magnet is located on the stator, and the magnetic field is adjusted by adjusting the current of the excitation winding. After increasing the field winding, the number of motor winding sets is more, which makes the structure of the motor complex. Sometimes there will be multiple sets of windings in one slot or there are both phase windings and field windings. The phase-to-phase insulation needs to be added in the slot, and the winding off-line process Complicated, the slot utilization rate is low, and the excitation slot needs to be added, the mechanical structure of the motor is seriously fragmented, the assembly and fixing are difficult, the processing technology is complicated, and the cost of the motor is high. More importantly, after adding the field winding, at least one more power switching device needs to be added to control the current of the field winding, which further increases the cost of the power circuit. Moreover, the magnetic flux generated by the field winding and the main flux share the main magnetic field. circuit and main air gap, the excitation effect is limited by other design parameters of the motor. Once the motor is manufactured, the excitation effect can only be controlled by adjusting the excitation current, and the excitation flux cannot be controlled by separately designing the excitation magnetic circuit.

Therefore, it is very important to seek a hybrid excitation permanent magnet motor with simple body structure, low cost, flexible magnetic adjustment function but a small number of power switching devices, and low cost of controller and power circuit.

Contents of the invention

In order to solve the deficiencies in the prior art, the present invention discloses a double-winding high power density hybrid excitation permanent magnet motor, which has the following characteristics:

1. The motor of the present invention is a hybrid excitation permanent magnet motor. There are only one set of stator armature windings A and one set of field windings F on the stator, and only one set of windings is placed in each slot of the motor. There is no need for interphase insulation in the slots, and the motor windings The off-line process is simple, and the overall cost is lower than that of various existing three-phase induction motors and permanent magnet motors. Since there is no need for phase-to-phase insulation in the slot, the slot fullness rate is high.

2. The permanent magnet of the motor of the present invention is fixed on the stator and does not rotate with the rotor. It is easy to install and is conducive to heat dissipation. It eliminates the mechanical stress damage of the ordinary single-phase permanent magnet motor due to the rotation of the permanent magnet with the rotor, and the disadvantages of poor heat dissipation of the permanent magnet. ; The power density of the motor of the present invention is high, and the utilization rate of materials is high. For the motor with the same design power, the motor of the present invention saves material consumption and reduces costs.

3. When the motor of the present invention is running, only one set of armature winding A passes through AC current, while the field winding F passes through a direct current with a constant direction, so the control circuit of the motor only needs two power electronic power switching devices, such as IGBT or MOSFET , as shown in Figure 1, while the existing various types of induction motors and permanent magnet motors have three-phase or more armature windings on their stators, which require at least 6 power electronic power switching devices, as shown in Figure 2, therefore, the present invention The control system of the motor requires few switching devices, low cost and simple structure. In addition, due to the small number of power switching devices, the possibility of failure of the power switching devices in the motor control circuit is reduced, and the reliability is improved.

4. The excitation magnetic field can be adjusted when the motor of the present invention is running, and the magnetic flux density in the air gap of the motor can be adjusted by adjusting the current of the excitation winding F. The excitation winding of the motor of the present invention is placed under the additional air gap, and the two are placed side by side. The excitation winding The generated magnetic flux directly passes through the additional air gap, the stator teeth, the main air gap and the rotor teeth form a closed loop, the excitation magnetic flux does not pass through the permanent magnet, and forms a parallel relationship with the magnetic flux generated by the permanent magnet, which not only effectively improves the field weakening efficiency , and avoid the risk of irreversible demagnetization such as the decrease of the magnetic properties of the permanent magnet due to reverse magnetization.

5. The permanent magnets of the motor of the present invention can be selected flexibly. Both permanent magnets with high magnetic energy products can be selected, and permanent magnets with low magnetic energy products such as ferrite can be selected, because the residual magnetism of the permanent magnets can be determined by the design air gap flux density of the motor. Magnetic density, and then determine the magnetic energy product of the permanent magnet by changing the pole arc coefficient of the permanent magnet. However, the existing permanent magnet motor is limited by the number of poles due to the pole arc coefficient. Usually, only high-performance permanent magnets can meet the design magnetic density. .

6. Since the difference in the width of the additional air gap will significantly change the reluctance of the motor magnetic circuit, affect the leakage flux between the permanent magnets, and then affect the magnetization and field weakening effects of the motor, therefore, the width of the additional air gap can be changed or By adopting the air gap structure with different upper and lower widths, different motor characteristics can be obtained by changing the additional air gap width of the motor, so as to meet the needs of different applications.

To achieve the above object, the specific scheme of the present invention is as follows:

A double-winding high power density hybrid excitation permanent magnet motor, including a stator and a rotor, the stator includes a stator yoke composed of a stator slot yoke and a stator back yoke, and a permanent magnet is arranged between the stator slot yoke and the stator back yoke The stator slot yoke is located at the bottom of the stator slot close to the outer circumference direction, the stator slot includes the slot where the armature winding is located, that is, the armature slot, and the slot where the excitation winding is located, that is, the excitation slot, and the armature slot and the excitation slot are arranged alternately along the circumference, A set of armature windings is placed in the armature slot, and a set of excitation windings is placed in the excitation slot;

The rotor includes rotor teeth, rotor slots are provided between adjacent rotor teeth, and a main air gap is provided between the stator teeth and rotor teeth; To disconnect, with additional air gap;

When the motor is running, the current magnitude and direction of a set of armature windings are controlled. The field windings pass a DC current in the same direction. Through strengthening or canceling each other, the stator magnetic field is continuously turned on or off in a certain direction, and the torque is generated by the change of reluctance between the stator and the rotor.

Further, part of the magnetic flux generated by two adjacent permanent magnets enters the rotor through the main air gap to form the main magnetic flux, and the other part enters the rotor without passing through the main air gap and passes through the additional air gap to form leakage flux. The total magnetic flux of the rotor is constant, and the magnitude of the leakage flux can be adjusted by adjusting the magnitude of the current in the excitation winding, and then the magnitude of the main flux entering the rotor through the main air gap can be adjusted, so as to realize the function of regulating the excitation.

Further, the number n _s of the stator teeth of the motor satisfies: n _s =2*n, where n is a natural number greater than or equal to 2;

The number n _r of the rotor teeth of the motor and the number n _s of the stator teeth of the motor satisfy: n _r = n _s /2;

The number n _pm of permanent magnets and the number n _s of motor stator teeth satisfy: n _{pm /m=0.5*ns} , m is a natural number greater than or equal to 1.

Further, the permanent magnets are magnetized in parallel or in the radial direction, and each permanent magnet can be formed by magnetizing a whole permanent magnet, or spliced by multiple permanent magnets with narrower widths, so The pole arc widths of the permanent magnets can be the same or different, the magnetization directions of the permanent magnets on the same stator slot yoke are the same, and the magnetization directions of the permanent magnets on two adjacent stator slot yokes are opposite.

Further, the magnetic flux generated by the field winding passes through the additional air gap, the stator teeth, the main air gap and the rotor teeth to form a closed loop, the magnetic flux generated by the field winding does not pass through the permanent magnet, and forms a parallel relationship with the magnetic flux generated by the permanent magnet ; It reduces the reluctance of the corresponding circuit of the excitation flux, and the same excitation current can generate a larger excitation flux, which not only effectively improves the efficiency of field weakening, but also avoids the permanent magnet’s reverse reaction caused by the excitation flux passing through the permanent magnet. The risk of irreversible demagnetization, such as the decrease of magnetic properties caused by magnetization, enhances the reliability of the motor.

Further, the additional air gap can be a uniform air gap with the same width everywhere, or a non-uniform air gap with different widths everywhere; the width of the additional air gap can be changed or the upper and lower unequal width air gap structures can be used to obtain different Magnetic enhancement and magnetic weakening characteristics to meet the needs of different applications.

Further, the armature winding passes through the slot where one armature winding is located, and passes through the adjacent armature slot, and the windings in two adjacent armature slots form an armature coil, and each armature coil traverses Across two stator tooth pitches, the currents of the windings in two adjacent armature slots have the same magnitude and opposite directions.

Further, the excitation winding enters from the slot where one excitation winding is located, and exits from the adjacent excitation slot, and the windings in two adjacent excitation slots form an excitation coil, and each excitation coil spans two stator tooth pitches , the currents of the windings in the slots where the two adjacent excitation windings are located are the same in magnitude and opposite in direction.

Further, the pole arc width of the permanent magnet of the motor can be flexibly determined according to the magnetic energy product or remanence density of the permanent magnet; the remanence density of the permanent magnet can be determined according to the design air gap flux density of the motor, and then by changing the permanent magnet The pole arc coefficient is used to determine the magnetic energy product of the permanent magnet. However, because the pole arc coefficient of existing permanent magnet motors is limited by the number of poles, usually only high-performance permanent magnets can meet the design flux density requirements.

Among them, the remanence density of the permanent magnet is proportional to the width of the permanent magnet, so the permanent magnet with high magnetic energy product or high remanence density can significantly reduce the width of the permanent magnet and reduce the amount of the permanent magnet. In fact, the energy product is the product of the permanent magnet’s remanence density and coercive force, but those skilled in the art pay more attention to the remanence density, so a high energy product generally represents a high remanence density.

Further, the permanent magnet can be made of high energy product permanent magnet material (such as neodymium iron boron) or low magnetic energy product permanent magnet material (such as ferrite or alnico).

The rotor is a symmetrical salient pole rotor, a stepped rotor or a turbine-shaped rotor.

Only one set of armature windings or excitation windings is placed in the stator slots, no phase-to-phase insulation is required in the stator slots, the slot utilization rate is high, the winding off-line process is simple, and the manufacturing cost is low.

The permanent magnet is in close contact with both the stator back yoke core and the stator slot yoke core.

The additional air gap can be filled with non-magnetic materials such as epoxy resin to improve the integrity of the motor structure.

The stator teeth, the stator yoke and the rotor teeth are all made of laminated silicon steel sheets or made of a high magnetic permeability iron core material at one time.

The permanent magnet is rectangular, arc-shaped or tile-shaped.

Specifically, the motor of the present invention works in this way. The stator core and rotor core of the motor of the present invention are made of laminated silicon steel sheets or iron core materials with high magnetic permeability. When the armature winding and the field winding are not energized , part of the magnetic flux generated by the permanent magnet passes through the stator slot yoke, the stator teeth and the main air gap flow into the rotor teeth along the radial direction of the motor, and then flows out to the main air gap through the adjacent rotor teeth to reach the permanent magnet under the other pole , and then closed through the stator back yoke, which forms the main magnetic flux of the motor; the other part of the magnetic flux generated by the permanent magnet does not pass through the main air gap, but passes through the additional air gap through the stator slot yoke, and enters the adjacent another The permanent magnet under the stator slot yoke is closed by the back yoke of the stator. This part of the magnetic flux does not enter the main air gap and the rotor, but only closes inside the stator. This part of the magnetic flux is the leakage flux. There is an excitation slot near the center of the circle under the auxiliary air gap, and an excitation winding is placed in the excitation slot. When the excitation winding passes current, the magnetic field generated by the excitation winding will enhance or weaken the main magnetic flux according to the direction of the current. The larger the excitation winding current , the stronger the enhancement or weakening effect on the main magnetic flux, because the magnetic potential of the field winding and the permanent magnet are connected in parallel, the total magnetic flux generated by the permanent magnet is constant. Therefore, the direction and magnitude of the current in the field winding can be adjusted. The size of the leakage magnetic flux, and then adjust the size of the main magnetic flux entering the rotor through the main air gap, so as to realize the function of adjusting the excitation. When the armature winding is energized, the magnetic field generated by the armature winding current causes the stator teeth on both sides of the armature slot where the armature winding is located to present different polarities, which is superimposed with the magnetic field generated by the permanent magnet, making one stator tooth display polarity , the main magnetic flux passes through, and the other adjacent stator tooth has no polarity and no magnetic flux flows. Since the armature winding is arranged every other slot, half of the stator teeth in the motor have polarity, and half The stator teeth of the stator have no polarity. According to the principle of minimum reluctance, the rotor will rotate until the rotor teeth coincide with the polar stator teeth. Since the number of rotor teeth is half of the number of stator teeth, at this time, each rotor tooth coincides with the stator teeth. The teeth are facing each other. This position is the alignment position of the rotor teeth and the stator teeth. This position corresponds to the minimum reluctance. At this time, if the rotor is to continue to rotate, the direction of the current in the armature winding needs to be changed, so that the stator teeth that have no polarity just now show polarity, while the stator teeth that had polarity do not show polarity. At this time, according to the magnetic Based on the principle of minimum resistance, the rotor teeth will have a tendency to rotate to align with the current four polarized stator teeth, so the rotor will rotate under force. When the rotor teeth and the stator overlap again, the direction of the armature winding current will continue to change. This process will repeat forever and the rotor will continue to spin. Since the main magnetic flux entering the rotor teeth through the main air gap can be adjusted by the above-mentioned excitation current, the motor of the present invention can realize magnetization-increasing operation and flux-weakening operation according to actual working conditions, widen the economical operating range of the motor, and reduce manufacturing costs , improve motor efficiency.

Beneficial effects of the present invention:

1. The DC current of the motor excitation winding of the present invention has a constant direction, and only needs to control the current magnitude and direction of a set of armature windings, so only two power switching devices are needed, while ordinary three-phase motors need at least 6 power switches devices, the number of power switching devices required by the motor controller is small, and the cost is low.

2. When the motor of the present invention is running, the magnetic fields generated by the armature winding and the field winding are mutually enhanced or canceled on the stator teeth. When the motor is running, the armature winding and the field winding are energized at the same time in a full cycle. Therefore, the power density of the motor of the present invention is high, and the material The utilization rate is high, and the motor with the same design power saves material consumption and reduces costs.

3. The permanent magnet of the motor of the present invention is fixed on the stator and does not rotate with the rotor. It is easy to install and is conducive to heat dissipation. It eliminates the mechanical stress damage of the ordinary single-phase permanent magnet motor due to the rotation of the permanent magnet with the rotor, and the disadvantages of poor heat dissipation of the permanent magnet. .

4. Only one set of windings is placed in each stator slot of the motor of the present invention, the off-line process of the motor windings is simple, and there is no need to place phase-to-phase insulation in the slots, which is beneficial to improving slot fullness and slot utilization.

5. In addition to the main air gap, the motor of the present invention is also provided with an additional air gap, which is cleverly designed in the radial direction of the motor, and the additional air gap will not increase the outer diameter of the motor; two adjacent permanent magnets produce Part of the magnetic flux enters the rotor through the main air gap to form the main magnetic flux, and the other part enters the rotor without passing through the main air gap and passes through the additional air gap to form leakage flux. Since the total magnetic flux generated by the permanent magnet is constant, by adjusting the excitation The size of the current in the winding can easily adjust the size of the leakage flux, and then adjust the size of the main magnetic flux entering the rotor through the main air gap, which can not only increase the magnetic field, but also play the role of weakening the magnetic field, effectively widening the The speed output range and power output range of the motor significantly improve the performance of the motor.

6. The shape and size of the additional air gap can be flexibly changed according to different magnetic field weakening needs. Equal width air gaps, upper wide and lower narrow air gaps, or upper narrow and lower wide air gaps can be used to achieve different magnetic field weakening effects; excitation windings The generated magnetic flux passes through the additional air gap, the stator teeth, the main air gap and the rotor teeth form a closed loop, the magnetic flux generated by the field winding does not pass through the permanent magnet, and forms a parallel relationship with the magnetic flux generated by the permanent magnet, which reduces the field magnetic flux Corresponding to the reluctance of the circuit, the same excitation current can generate a larger excitation flux, which not only effectively improves the efficiency of field weakening, but also avoids the magnetic performance of the permanent magnet caused by the reverse magnetization of the permanent magnet caused by the excitation flux passing through the permanent magnet. The risk of irreversible demagnetization, such as falling, enhances the reliability of the motor.

7. The torque dead zone can be eliminated by changing the rotor structure of the motor of the present invention, and the starting performance of the motor can be improved, for example, an asymmetric rotor, a turbine-shaped rotor or a stepped rotor can be used.

8. Due to the high cost of permanent magnets with wider pole arc widths, they are prone to breakage when mechanically stressed, and it is more difficult to install. The mechanical strength is not as good as the splicing of multiple permanent magnets with smaller pole arc widths. The permanent magnet in the motor can be a permanent magnet magnetized as a whole, and can also be spliced by multiple permanent magnets. Therefore, the manufacturing process of the motor of the present invention is simple and the cost is low; because the pole arc width of the permanent magnet of the motor of the present invention can be based on The design magnetic energy product or design residual magnetic density of the permanent magnet is determined flexibly, so the motor of the present invention can adopt both high magnetic energy product permanent magnets and low magnetic energy product permanent magnets, and high magnetic energy product permanent magnets and low magnetic energy product permanent magnets can also be used. The magnets are mixed and matched. In the actual design, the residual magnetic density of the permanent magnet can be determined according to the design air gap flux density of the motor, and then the magnetic energy product of the required permanent magnet can be determined by the pole arc coefficient of the permanent magnet. The arc coefficient is limited by the number of poles, and usually only high-performance permanent magnets can meet the needs of high-performance motors.

9. The permanent magnet of the motor of the present invention does not directly face the air gap, and can be magnetized radially or parallelly. The influence of the magnetizing method on the performance of the motor can be compensated by changing the pole arc width of the permanent magnet, while for other For surface-mounted permanent magnet motors, the magnetic flux decreases when parallel magnetization is used, which will significantly affect the performance of the motor. Radial magnetization is difficult to achieve and the processing cost is high.

Description of drawings

The power converter circuit diagram of Fig. 1 motor of the present invention;

Fig. 2 existing brushless DC permanent magnet and permanent magnet synchronous motor power converter circuit diagram;

Fig. 3 is a structural schematic diagram of Embodiment 1 of the motor of the present invention;

Fig. 4 is a schematic structural diagram of motor embodiment 2 of the present invention;

Fig. 5 is a structural schematic diagram of Embodiment 3 of the motor of the present invention;

Among them, 1. Stator teeth, 2. Stator back yoke, 3. Stator slot yoke, 4. Armature slot, 5. Excitation slot, 6. Armature winding, 7. Excitation winding, 8. Permanent magnet, 9. Rotor tooth , 10. Rotor slot, 11. Main air gap, 12 additional air gap.

detailed description:

The present invention is described in detail below in conjunction with accompanying drawing:

Embodiment 1 As shown in Figure 3, the number of teeth of the motor stator in this embodiment is 8, the number of teeth of the rotor is 4, and the number of permanent magnet blocks is 4. This embodiment includes a stator, a rotor, a main air gap and an additional air gap, and the stator includes a stator iron core, permanent magnets and stator slots, the stator core includes stator teeth 1, stator back yoke 2 and stator slot yoke 3, the stator core is made of ferromagnetic material with high magnetic permeability, the stator core is provided with stator slots, stator slots Including the armature slot 4 and the excitation slot 5, the armature slot 4 and the excitation slot 5 are alternately arranged at intervals, and the armature winding 6 is placed in the armature slot 4, and the armature winding 6 penetrates from one armature slot 4, and from the adjacent The other armature slot passes through to form a coil, so that the current in each adjacent two armature slots is the same in size and opposite in direction, and the excitation winding 7 is placed in the excitation slot 5, and the excitation winding 7 passes through one excitation slot 5 It enters and passes through another adjacent excitation slot to form a coil, so that the current in each adjacent two excitation slots is the same in size and opposite in direction; an arc-shaped permanent Magnet 8, permanent magnet 8 adopts ferrite permanent magnet material with low magnetic energy product, permanent magnet 8 adopts parallel magnetization, and the magnetization directions of two adjacent permanent magnets are opposite; the rotor includes rotor teeth 9 and rotor grooves 10, rotor teeth 9 are symmetrically distributed along the circumference, and a main air gap 11 is provided between the rotor teeth 9 and the stator teeth 1; the stator slot yoke 3 above the slot where the excitation winding 7 is located is disconnected, and an additional air gap 12 is set, and the additional air gap 12 is set on the motor In the radial direction, the widths of the additional air gaps 12 are equal everywhere.

Embodiment 2 As shown in Figure 4, the number of teeth of the stator of the motor in this embodiment is 8, the number of teeth of the rotor is 4, and the number of permanent magnet blocks is 16. This embodiment includes a stator, a rotor, a main air gap and an additional air gap, and the stator includes a stator iron core, permanent magnets and stator slots, the stator core includes stator teeth 1, stator back yoke 2 and stator slot yoke 3, the stator core is made of ferromagnetic material with high magnetic permeability, the stator core is provided with stator slots, stator slots Including the armature slot 4 and the excitation slot 5, the armature slot and the excitation slot are alternately arranged at intervals, and the armature winding 6 is placed in the armature slot 4, and the armature winding 6 penetrates from one armature slot 4, and from the adjacent other One armature slot passes through to form a coil, so that the current in each adjacent two armature slots has the same magnitude and opposite direction, and the excitation winding 7 is placed in the excitation slot 5, and the excitation winding 7 penetrates from one excitation slot 5, Pass through another adjacent excitation slot to form a coil, so that the current in each adjacent two excitation slots has the same magnitude and opposite direction; an arc-shaped permanent magnet 8 is placed between the stator slot yoke 3 and the stator back yoke 2 , there are 4 permanent magnets on each stator slot yoke 3, the permanent magnet 8 adopts NdFeB permanent magnet material with high magnetic energy product, the permanent magnet 8 adopts radial magnetization, and the 4 permanent magnets on the same stator slot yoke The magnetization direction is the same, and the magnetization direction of the permanent magnets on the adjacent different stator slot yokes is opposite; the rotor includes rotor teeth 9 and rotor slots 10, and the rotor is turbine-shaped. When the rotor teeth 9 are aligned with the stator teeth 1, the rotor The reluctance of the teeth is different from that of two adjacent stator teeth, which is beneficial to eliminate the torque dead zone and improve the starting performance of the motor; there is a main air gap 11 between the rotor teeth 9 and the stator teeth 1; the upper part of the slot where the excitation winding 7 is located The stator slot yoke is disconnected, and an additional air gap 12 is provided. The additional air gap 12 is arranged in the radial direction of the motor. The width of the additional air gap 12 near the armature slot is narrow, and the width near the stator back yoke is wide.

Embodiment 3 As shown in Figure 5, the number of teeth of the motor stator in this embodiment is 8, the number of teeth of the rotor is 4, and the number of permanent magnet blocks is 12. This embodiment includes a stator, a rotor, a main air gap and an additional air gap, and the stator includes a stator iron core, permanent magnets and stator slots, the stator core includes stator teeth 1, stator back yoke 2 and stator slot yoke 3, the stator core is made of ferromagnetic material with high magnetic permeability, the stator core is provided with stator slots, stator slots Including the armature slot 4 and the excitation slot 5, the armature slot 4 and the excitation slot 5 are alternately arranged at intervals, and the armature winding 6 is placed in the armature slot, and the armature winding 6 penetrates from one armature slot 4, and from the adjacent The other armature slot passes through to form a coil, so that the current in every two adjacent armature slots has the same magnitude and opposite direction, and the excitation winding 7 is placed in the excitation slot 5, and the excitation winding 7 penetrates from one excitation slot. Pass through another adjacent excitation slot to form a coil, so that the current in each adjacent two excitation slots has the same magnitude and opposite direction; an arc-shaped permanent magnet 8 is placed between the stator slot yoke 3 and the stator back yoke 2 , there are three permanent magnets on each stator slot yoke, permanent magnet 8 is made of AlNiCo permanent magnet material with low magnetic energy product, permanent magnet 8 adopts parallel magnetization, and the magnetization of three permanent magnets on the same stator slot yoke The direction is the same, and the magnetization directions of the permanent magnets on the adjacent different stator slot yokes are opposite; the rotor includes rotor teeth 9 and rotor slots 10, and the rotor has a stepped air gap structure. When the rotor teeth 9 are aligned with the stator teeth 1, the The reluctance of the rotor teeth is different from that of the two adjacent stator teeth, which is beneficial to eliminate the torque dead zone and improve the starting performance of the motor; there is a main air gap 11 between the rotor teeth 9 and the stator teeth 1; the excitation winding 7 is located above the slot The stator slot yoke is disconnected, and an additional air gap 12 is set. The additional air gap 12 is arranged in the radial direction of the motor. The width of the additional air gap 12 near the armature slot is wider, and the width near the stator back yoke is narrower.

Although the specific implementation of the present invention has been described above in conjunction with the accompanying drawings, it does not limit the protection scope of the present invention. Those skilled in the art should understand that on the basis of the technical solution of the present invention, those skilled in the art do not need to pay creative work Various modifications or variations that can be made are still within the protection scope of the present invention.

Claims (7)

1. a kind of double winding high power density composite excitation permanent magnet motor, it is characterized in that, including stator and rotor, the stator Including the stator yoke being made up of stator slot yoke and stator back yoke, permanent magnet is provided between the stator slot yoke and stator back yoke, it is fixed Pilot trench yoke is located at stator trench bottom near cylindrical circumferential direction, and groove where the stator slot includes armature winding is armature slot and excitation Groove where winding is excitation groove, the armature slot and the circumferentially alternate intervals arrangement of excitation groove, and one is laid in the armature slot Set armature winding, set of excitation winding is laid in the excitation groove；

The rotor includes rotor tooth, and rotor slot is provided between adjacent rotor tooth, is provided between the stator tooth and rotor tooth Main air gap；The stator slot yoke portion of top radially disconnects in excitation groove where the Exciting Windings for Transverse Differential Protection, is provided with additional air gap；

During motor operation, size of current and the direction of a set of armature winding, the constant direct current in the logical direction of the Exciting Windings for Transverse Differential Protection are controlled Electric current, the magnetic field interaction that armature supply magnetic field, exciting current magnetic field and permanent magnet are produced causes the magnetic flux phase on stator tooth Mutually enhancing or counteracting, stator field is continuously opened or turned off in a certain direction, using magnetic resistance change rate between stator and rotor Produce torque；

The number n of the motor stator tooth_sMeet：n_s=2*n, wherein n are greater than the natural number equal to 2；

The number n of the rotor tooth_rWith the number n of motor stator tooth_sMeet：n_r=n_s/2；

The block number n of the permanent magnet_pmWith the number n of motor stator tooth_sMeet：n_pm/ m=0.5*n_s, m is oneself more than or equal to 1 So count；

A part of magnetic flux that adjacent two pieces of permanent magnets are produced enters rotor and forms main flux by main air gap, another part without Main air gap closes to form leakage magnetic flux into rotor by the additional air gap, because the total magnetic flux that permanent magnet is produced is certain , the size of the leakage magnetic flux can be adjusted by the size for adjusting electric current in Exciting Windings for Transverse Differential Protection, and then adjust by the entrance of main air gap The size of the main flux in rotor, realizes adjusting the effect of excitation with this；

The magnetic flux that the Exciting Windings for Transverse Differential Protection is produced is by additional air gap, stator tooth, main air gap and rotor tooth form into closed-loop path, excitation The magnetic flux that winding is produced forms parallel relationship without permanent magnet with the magnetic flux that permanent magnet is produced.

2. a kind of double winding high power density composite excitation permanent magnet motor as claimed in claim 1, it is characterized in that, it is described forever Magnet is parallel magnetization or radial magnetizing, and every piece of permanent magnet can both be magnetized by a monoblock permanent magnet and be formed, it is also possible to by many The permanent magnet of block narrower width is spliced, and the polar arc width of the permanent magnet can be with identical, it is also possible to different, described same The magnetizing direction of the permanent magnet on stator slot yoke is identical, and the magnetizing direction of the permanent magnet in two neighboring stator slot yoke portion is opposite.

3. a kind of double winding high power density composite excitation permanent magnet motor as claimed in claim 1, it is characterized in that, it is described attached Aerating gap can be width identical even air gap everywhere, or the different non-homogeneous air gap of width everywhere.

4. a kind of double winding high power density composite excitation permanent magnet motor as claimed in claim 1, it is characterized in that, the electricity Groove where pivot winding a from armature winding is penetrated, and is passed from adjacent armature slot, the winding composition in two neighboring armature slot One armature coil, each armature coil across two stator tooths away from, the size of current of winding is identical in two neighboring armature slot, In the opposite direction.

5. a kind of double winding high power density composite excitation permanent magnet motor as claimed in claim 1, it is characterized in that, it is described to encourage Groove where magnetic winding a from Exciting Windings for Transverse Differential Protection is penetrated, and is passed from adjacent excitation groove, the winding composition in two neighboring excitation groove One magnet exciting coil, each magnet exciting coil is across two stator tooths away from the electric current of winding in groove where two neighboring Exciting Windings for Transverse Differential Protection Size is identical, in the opposite direction.

6. a kind of double winding high power density composite excitation permanent magnet motor as claimed in claim 2, it is characterized in that, motor The polar arc width of permanent magnet can flexibly be determined by the magnetic energy product or residual flux density according to permanent magnet.

7. a kind of double winding high power density composite excitation permanent magnet motor as claimed in claim 1, it is characterized in that, it is described forever Magnet both can be made of high energy product permanent-magnet material can also be low magnetic energy product permanent-magnet material.