CN105226861B - A kind of ring-shaped yoke portion Exciting Windings for Transverse Differential Protection high power density composite excitation permanent magnet motor - Google Patents

Abstract

The invention discloses a high power density hybrid excitation permanent magnet motor with an annular yoke excitation winding, 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 is a permanent magnet between them, and 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. The armature slot and the excitation slot are along the The circumference is 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 High Power Density Hybrid Excitation Permanent Magnet Motor with Toroidal Yoke Excitation Winding

technical field

The invention relates to a permanent magnet motor, in particular to a high power density hybrid excitation permanent magnet motor of an annular yoke excitation winding.

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

In addition, the existing permanent magnet motors mostly use distributed windings or concentrated windings spanning multiple pole pitches, which generally have long winding ends, a large amount of copper, high manufacturing costs, high copper consumption during motor operation, and low efficiency. Disadvantages, especially for motors with large outer diameter and small axial length, that is, a large ratio of diameter to length, this disadvantage is particularly prominent, and special winding coil connection methods are required to reduce the winding end and reduce the use of Copper to improve motor operating efficiency.

Contents of the invention

In order to solve the deficiencies in the prior art, the present invention discloses a high power density hybrid excitation permanent magnet motor with an annular yoke excitation winding. The permanent magnet motor of the present invention 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. An excitation winding is placed in the excitation slot of the motor of the present invention. The excitation winding penetrates through an excitation slot, and then passes out along the outer side of the stator back yoke in the direction of the outer diameter to form a coil. The excitation winding surrounds the stator slot yoke, the permanent magnet and the stator Back-yoke winding, the excitation winding in each excitation slot is a set of coils, forming a total of 4 sets of coils, and the 4 sets of coils can be connected in series or in parallel.

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. The power density of the motor of the present invention is high, and the utilization rate of materials is high. With the motor of the same design power, the motor of the present invention saves material consumption and reduces costs; when the motor of the present invention is in operation, only one set of armature winding A passes AC current, and the field winding F passes 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 stators of various induction motors and permanent magnet motors are Armature windings with three phases or above require at least 6 power electronic power switching devices, as shown in Figure 2. Therefore, the motor control system of the present invention requires fewer 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.

5. 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 performance of the permanent magnet due to reverse magnetization. product permanent magnet, because the remanence density of the permanent magnet can be determined by the design air gap flux density of the motor, and then the magnetic energy product of the permanent magnet can be determined by changing the pole arc coefficient of the permanent magnet, while the existing permanent magnet motor is due to the pole arc coefficient Limited by the number of poles, usually only high-performance permanent magnets can meet the design magnetic density requirements.

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 high power density hybrid excitation permanent magnet motor with an annular yoke excitation winding, 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 The magnet, 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 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 excitation winding penetrates through an excitation slot, and then passes out along the outside of the stator back yoke in the outer diameter direction to form a coil. The excitation winding surrounds the stator slot yoke, the permanent magnet and the stator back yoke are wound, and the excitation in each excitation slot The winding is a set of coils;

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

The number nr of the motor rotor teeth and the number ns of the motor stator teeth satisfy: nr=ns/2;

The number npm of permanent magnets and the number ns of motor stator teeth satisfy: npm/m=0.5*ns, m is a natural number greater than or equal to 1.

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 the slots where the two adjacent armature windings are located are the same in magnitude and opposite in direction.

Further, the excitation winding in each excitation slot is a set of coils, forming 4 sets of excitation coils in total, and the 4 sets of coils can be connected in parallel or in series. The number of turns of the four sets of coils of the excitation winding may be the same or different, and the stator back yoke may be provided with a groove or an iron core baffle to fix the excitation winding.

The number of excitation coils is determined by the number of excitation slots, which is half the number of stator teeth and equal to the number of rotor teeth.

The excitation winding is a simple concentrated winding, which penetrates from an excitation slot and exits along the outside of the stator back yoke in the direction of the outer diameter to form a coil. The excitation winding surrounds the stator slot yoke, and the permanent magnet and the stator back yoke are wound. When the length ratio is large, the length of the end winding can be effectively reduced, the amount of copper used can be reduced, the cost of the motor can be reduced, the copper consumption of the motor can be reduced, and the efficiency can be improved.

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 pole of the permanent magnet The arc coefficient is used to determine the magnetic energy product of the permanent magnet. However, the current 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 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 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.

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.

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

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 rectangular, arc-shaped or tile-shaped.

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

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

Specifically, the motor of the present invention works in this way. The stator core and the rotor core of the motor of the present invention are laminated with silicon steel sheets or made of high magnetic permeability core materials at one time. When the armature winding and the field winding are not energized At this time, 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. The magnet is 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 other The permanent magnet under the permanent magnet under the stator slot yoke is closed by the stator back yoke. 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. The excitation winding of the motor of the present invention is a simple concentrated winding, which is wound around the stator slot yoke, the permanent magnet and the stator yoke. When the diameter of the motor is relatively large, the amount of copper used at the end of the winding can be significantly reduced, and the manufacturing cost can be reduced. Copper consumption, improve motor operating efficiency; In addition to the main air gap, the motor of the present invention is also provided with an additional air gap, the additional air gap is skillfully designed in the radial direction of the motor, and the additional air gap will not increase the outer diameter of the motor; 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. Since the total magnetic flux generated by the permanent magnet is Certainly, by adjusting the magnitude of the current in the excitation winding, the magnitude of the leakage flux can be easily adjusted, and then the magnitude of the main flux entering the rotor through the main air gap can be adjusted, which can not only increase the magnetization, but also The magnetic field weakening effect can effectively expand the speed output range and power output range of the motor, and 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; 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 Wait.

7. Due to the high cost of the permanent magnet with a wider pole arc width of the motor, it is easy to break 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 a smaller pole arc width. The permanent magnet in the motor of the present invention 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 It can be flexibly determined according to the design energy product of the permanent magnet or the design remanence density, so the motor of the present invention can adopt either a permanent magnet with a high energy product or a permanent magnet with a low energy product, or a permanent magnet with a high energy product and a low magnetic energy. 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. However, the existing permanent magnet motor Since the pole arc coefficient is limited by the number of poles, usually only high-performance permanent magnets can meet the needs of high-performance motors.

8. 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;

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 ways:

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 excitation winding 7 is placed in the excitation slot 5, and the excitation winding 7 penetrates from one excitation slot 5, and then along the outer diameter direction along the stator The back yoke 2 passes through to form a coil, the excitation winding 7 surrounds the stator slot yoke 3, the permanent magnet 8 and the stator back yoke 2 are wound, and the excitation winding in each excitation slot is a set of coils, forming 4 sets of coils in total, 4 sets The coils can be connected in series or in parallel. Armature windings 6 are placed in the armature slots 4, and the armature windings 6 pass through one armature slot 4 and pass out from another adjacent armature slot to form a coil, so that each The currents in two adjacent armature slots have the same magnitude and opposite directions; an arc-shaped permanent magnet 8 is placed between the stator slot yoke 3 and the stator back yoke 2, and the permanent magnet 8 is made of ferrite permanent magnet material with low magnetic energy product. The permanent magnets are magnetized in parallel, and the magnetization directions of two adjacent permanent magnets are opposite; the rotor includes rotor teeth 9 and rotor slots 10, the rotor teeth 9 are symmetrically distributed along the circumference, and a main gas is arranged between the rotor teeth 9 and the stator teeth 1. Gap 11; the stator slot yoke above the excitation winding slot is disconnected in the radial direction, and an additional air gap 12 is set. The additional air gap 12 is arranged in the radial direction of the motor, and the width of the additional air gap 12 is 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 4 and the excitation slot 5 are alternately arranged at intervals, and the excitation winding 7 is placed in the excitation slot 5, and the excitation winding 7 penetrates from one excitation slot 5, and then along the outer diameter direction along the stator The back yoke passes through to form a coil. The excitation winding 7 is wound around the stator slot yoke 3, the permanent magnet 8 and the stator back yoke 2. The excitation winding in each excitation slot is a set of coils, forming a total of 4 sets of coils, 4 sets of coils They can be connected in series or in parallel with each other. Armature windings 6 are placed in the armature slots 4, and the armature windings 6 pass through one armature slot 4 and pass out from another adjacent armature slot to form a coil, so that each phase The currents in two adjacent armature slots have the same magnitude and opposite directions; arc-shaped permanent magnets 8 are placed between the stator slot yoke 3 and the stator back yoke 2, and there are 4 permanent magnets on each stator slot yoke 4, and the permanent magnets 8 The NdFeB permanent magnet material with high magnetic energy product is used, and the permanent magnet adopts radial magnetization. The magnetization direction of the four permanent magnets on the same stator slot yoke is the same, and the magnetization direction of the permanent magnets on different adjacent stator slot yokes The magnetic direction 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 teeth have different reluctance from the adjacent two stator teeth, which is conducive to torque elimination The dead zone improves the starting performance of the motor; there is a main air gap 11 between the rotor teeth 9 and the stator teeth 1; the yoke of the stator slot above the excitation winding is disconnected in the radial direction, and an additional air gap 12 is set. 12 is arranged in the radial direction of the motor, and the width of the additional air gap 12 near the armature slot is narrower, and the width near the stator back yoke is wider.

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 (8)

1. A high power density hybrid excitation permanent magnet motor with an annular yoke field field winding is characterized in that it includes a stator and a rotor, and the stator includes a stator yoke made up of a stator slot yoke and a stator back yoke, the stator slot yoke and the stator back yoke A permanent magnet is arranged between the yokes, and 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 field winding is located, that is, the excitation slot. The slots are alternately arranged at intervals along the circumference, a set of armature windings is placed in the armature slots, and a set of excitation windings is placed in the excitation slots; The excitation winding penetrates through an excitation slot, and then passes out along the outside of the stator back yoke in the outer diameter direction to form an excitation coil. The excitation winding surrounds the stator slot yoke, the permanent magnet and the stator back yoke are wound, and each excitation slot The field winding is a set of field coils; 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; the stator slot yoke above the excitation slot where the excitation winding is located radially open, with additional air gap; When the motor is running, the current magnitude and direction of a set of armature windings are controlled, and the field winding passes a direct current with a constant direction. The magnetic fluxes of the stators strengthen or cancel 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; 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; The rotor is a symmetrical salient pole rotor, a stepped rotor or a turbine-shaped rotor. 2. A kind of annular yoke excitation winding high power density hybrid excitation permanent magnet motor as claimed in claim 1, characterized in that, a 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 , the other part does not enter the rotor through the main air gap and closes through the additional air gap to form a leakage flux. Since the total magnetic flux generated by the permanent magnet is constant, the magnitude of the leakage flux is adjusted by adjusting the current in the excitation winding, and then Adjust the magnitude of the main magnetic flux entering the rotor through the main air gap, so as to realize the function of adjusting the excitation. 3. A kind of annular yoke excitation winding high power density hybrid excitation permanent magnet motor as claimed in claim 1, it is characterized in that, the number ns of described stator teeth satisfies: ns=2*n, wherein n is greater than or equal to the natural number of 2; The number nr of the rotor teeth and the number ns of the stator teeth satisfy: nr=ns/2; The number npm of permanent magnets and the number ns of stator teeth satisfy: npm/m=0.5*ns, m is a natural number greater than or equal to 1. 4. A kind of annular yoke excitation winding high power density hybrid excitation permanent magnet motor as claimed in claim 1, is characterized in that, described additional air gap is the uniform air gap of same width everywhere or the non-uniform air gap of different width everywhere. Uniform air gap. 5. A kind of annular yoke excitation winding high power density hybrid excitation permanent magnet motor as claimed in claim 1, it is characterized in that, the armature winding penetrates from the slot where an armature winding is located, and enters from the adjacent armature winding The armature windings in two adjacent armature slots form an armature coil, and each armature coil spans two stator tooth pitches, and the current of the armature windings in the slots where the two adjacent armature windings are located Same size, opposite directions. 6 . A high power density hybrid excitation permanent magnet motor with ring yoke excitation windings as claimed in claim 1 or 3 , wherein the excitation windings in each excitation slot is a set of excitation coils. 7. A kind of annular yoke excitation winding high power density hybrid excitation permanent magnet motor as claimed in claim 1, characterized in that, the permanent magnets are magnetized in parallel or radially, and the pole arcs of the permanent magnets The widths are 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. 8. A high power density hybrid excitation permanent magnet motor with an annular yoke excitation winding as claimed in claim 7, wherein the pole arc width of the permanent magnet is flexibly determined according to the magnetic energy product or remanence density of the permanent magnet.