WO2000054391A1 - Electrical machine with large number of poles - Google Patents

Abstract

The invention relates to an improved structure of medium frequency and low speed electrical machine, in particular suitable for machine with large number of poles. Rotor is of permanent magnetic or electrically excited or induced, and number of poles is more than or equal to 8, armature windings consist of solid conductor and are arranged in layers with equal or varying pitch in slot, each turn of conductor adjacent to wall of the slot. Compared to the prior art, the invention save copper and ferrum, improve efficiency and easy to manufacture winding. It also applies to other cases except to replace common medium frequency machine.

Description

 FIELD OF THE INVENTION

 The invention relates to an improved structure of an intermediate frequency motor and a low speed motor, and is particularly suitable for a motor with a large number of poles. BACKGROUND OF THE INVENTION

 There are mainly two types of intermediate frequency motor technology in the prior art. The first is an inductive sub-type. Based on DC excitation, high-frequency harmonics are induced. The disadvantage of this method is that only the harmonic magnetic field is used, which results in a large motor, consumes materials, has a small output, and has low efficiency. Another intermediate frequency motor technology is claw pole type. Although it is a motor with a higher number of poles, due to the claw pole structure, the magnetic circuit is longer, and the loss increases at higher frequencies. Limits high frequency applications. In addition, because the armature core of the prior art motor has a small number of poles, the total number of slots is small, and the slots cannot be too deep so that the leakage inductance increases and affects performance. That is, the slot cross section is narrow in the slot opening, and the slot body is wide to accommodate a larger number of windings. The disadvantage of this structure is that there must be some turns of electromagnetic wires in the tank body, which are located in the center of the tank body and not adjacent to the core of the tank wall. The core wall restricts the temperature rise performance of the motor, which also limits the increase in output. The purpose of the present invention is to provide a new type of intermediate frequency motor, in particular to provide a large pole number motor to overcome the defects and deficiencies of the above motor. Summary of the invention

The object of the present invention is achieved by the following technical solutions: The large-pole motor of the present invention, the rotor is a permanent magnet type or an electric excitation type or an inductive type, the number of poles is greater than or equal to 8; for armature windings The solid core wires are arranged in layers according to the layer and are arranged in equal and unequal to pitch wave windings. The windings are in the slots, and each turn of the wires is adjacent to the core of the slot wall. The object of the present invention can also be achieved by the following technical solutions: The large pole number motor of the present invention has a pole number greater than or equal to 8; the armature core is slotless: the windings are arranged in a single layer on the surface of the core: the windings are of equal pitch and are not Equal-pitch surface wave winding. The present invention can also use a unique pulse excitation method in a permanent magnet motor to achieve the purpose of increasing output, specifically the following technical solutions: a. One or more phase windings are provided as excitation windings on the armature side. For each The excitation winding has a charge and discharge excitation circuit; b. For each discharge circuit, there is a discharge trigger circuit, whose function is to make the triggering moment occur 30 times before and after the winding is directly opposite the magnetic pole. within. Compared with the prior art, the present invention has the advantages of saving copper, iron, high efficiency, large output, convenient winding processing, and can be applied to other occasions besides replacing general intermediate frequency motors. Brief description of the drawings

 The drawings of the present invention are explained as follows:

 Fig. 1 shows a slotted stator and a winding structure in the present invention, and a part of the core punching sheet and the winding cross-section in the case of each layer of double strands.

 Fig. 2 shows a slotted stator and a winding structure in the present invention, and a part of a core punching sheet and a winding cross-section of a single strand in each layer.

 Fig. 3 is a developed view of a skewed structure between a rotor pole and a stator cogging of a slot type large-pole permanent magnet motor according to the present invention.

 Fig. 4a is a developed view of an end non-overlapping winding when the number of phases m = 2 of the present invention. Fig. 4b is a current phasor diagram of the winding in Fig. 4a.

 FIG. 5 is a developed view of the whole-distance wave winding when m = 3 of the present invention.

 FIG. 6 is another developed view of the whole-wave winding when m = 3 of the present invention.

FIG. 7 is a developed view of partially overlapping wave windings when m = 3 and k = 2 of the present invention. FIG. 8 is a part and winding cross-sectional view of a slotted stator core punch of the present invention Meaning.

 Fig. 9 is a developed view of a surface wave winding with non-overlapping ends according to the present invention.

 FIG. 10 is an expanded view of a surface single-pitch full-length wave winding of m = 2 according to the present invention.

 Figure 11 shows a radial magnetized permanent magnet rotor in the present invention.

 Fig. 12 is a phasor diagram of the excitation current of the synchronous generator and the armature potential in the present invention.

 FIG. 13 is a waveform diagram of the fundamental wave of the armature potential of a synchronous motor in the present invention.

 FIG. 14 is a reference direction of the armature current of the synchronous generator of the present invention.

 FIG. 15 is a circuit configuration diagram of a pulse excitation method of a permanent magnet synchronous motor according to the present invention. FIG. 16 is a relationship diagram between the discharge time and the phase voltage of the excitation pulse of the present invention. FIG. 17 is a schematic diagram of the pulse parameters of the excitation pulse current of the present invention.

 Fig. 18 is a schematic diagram of the reference time of the excitation pulse discharge in the three-phase case of the present invention.

 Fig. 19 is an example of a pulse excitation circuit according to the present invention.

 FIG. 20 is a structural diagram of an electrically excited rotor of a large pole number motor of the present invention. Detailed description of the invention

The present invention is described in further detail below with reference to the drawings: The first type of large-pole motor is called a slotted type, and the arrangement of the stator core punches and windings in the slots is shown in Figures 1 and 2. The space occupied by the windings is a straight slot. In these two figures, 1 01 and 201 are open straight grooves, 103 and 203 are tooth portions, 104 and 204 are punching yoke portions, 102 and 202 are cross-sections of winding conductors arranged in layers in the slot, and 102 is The layer is wound with double-stranded solid wires, the picture shows the case of six layers; 202 is wound with each layer of single-stranded solid wires, the picture shows the case of four layers. It can be seen from Figures 1 and 2 that the single- and double-stranded layered and neat winding method is characterized in that each turn of the conductor in the slot is directly adjacent to the core of the slot wall except the insulation layer, which improves the temperature rise performance. . Of course, in the case of double strands, a slot wedge can be added to the slot to reduce additional losses. The rotor of this type of motor can be of permanent magnet type, electric excitation type, or induction type. The winding method of the armature winding is layered according to the principle of the shortest end. Wave windings of equal pitch and unequal pitch arranged neatly in layers include three types of winding methods. The first type is called wave winding with no overlapping ends; the second type is called full-length wave winding; and the third type is called partially overlapping wave winding. The first is a non-overlapping wave winding with m slots per pole. When the number of phases is m = 3, refer to the description of the patent number 94116889.1. The present invention is generalized to the case of the m phase, where m is an arbitrary integer. Figure 4a shows an expanded view of the winding structure of any layer when m = 2 in a straight slot. Its characteristics are that m windings bypass adjacent m slots in the same direction without overlapping at the ends, 407 are rotor magnetic poles, 408 are stator teeth, each pair of poles corresponds to 4 slots of the stator core, and two adjacent ones The electrical angle between the slots is 90 °, 401, 402 are m = 2 windings in the same layer. In the figure, they pass from the lower end to the adjacent head in the same direction and m = 2 slots. The upper ends do not overlap, and then go around the third and fourth slots in the same direction to return to the lower ends, and they do not overlap with each other.

403, 405, 406 are the current directions of the windings in four adjacent slots at a time. Figure 4b shows their phasors. The 413 and 414 phasors correspond to the current 403 in Figure 4a.

404, both belong to winding 401, and their combined phasor is J; 415, 416 correspond to the current 405 in Figure 4a, and 406 belong to the other winding 402, and their combined phasor is also J. Correctly select the polarity of 401, 402 Then, it can be connected in series or in parallel to obtain a composite phasor in the J direction, which represents the phasor of this layer of winding and becomes a phase winding. Phase windings of different layers move one slot parallel to each other. By placing the four layers in this way, 0 ° and 90 ° can be obtained. , 180. , 270. The four-phase phase winding. In particular, translating one pole pitch results in a phase winding with a phase shift of 180 °. The second type is a full-wave winding, which also has m slots per pole. When the number of phases is m = 3, there are two types of expansion diagrams in FIG. 5 and FIG. 6. In FIG. 5, 501, 502, and 503 are three-phase windings, respectively, and the pitch of each winding is a pole pitch, and 504 is the development surface of the teeth. The three-phase windings are wound on the same layer, and the ends overlap with each other, so more wire positions should be reserved at the ends. Fig. 6 has a similar situation, 604 corresponds to 504 in Fig. 5 and is also the development surface of the tooth: 601 corresponds to 501, 602 corresponds to 502, and 603 is actually obtained by moving 503 in parallel by a pole distance of 3 slots, So the two phases are opposite. The third is a partially overlapping wave winding. It has some of the characteristics of the two windings mentioned above. That is, the winding of each phase adopts the winding method with no overlapping winding at the end, and has a phase band greater than 0 °; the winding of one phase is translated to the other phase band to form another phase winding, between the windings of each phase of the same layer There is overlap at the end, and its expanded view is shown in FIG. 7. The figure shows a case where the number of phases is m-3, and the phase band of each phase occupies k = 2 slots. That is, each pole has m * k = 3 * 2 = 6 slots, and the phase band width is k-1 slot widths, that is, 30. Can improve the harmonic situation. 707 and 708 are the development surfaces of the teeth, and the distance between them includes a pair of poles. 701, 702 The two windings form a phase winding, and its winding method is similar to that of Figure 4a, that is, they bypass the adjacent 2 slots in the same direction without overlapping at the ends, but the number of slots passed has become larger. . Still spanning a polar distance. After moving the phase windings 701 and 702 in parallel by two slots, another phase windings 703 and 704 are obtained; by analogy, another phase 705 and 706 are obtained. These three phase windings overlap each other at the end similar to FIG. 6, of course, it can also be arranged according to the method of FIG. 5. It is not difficult to infer that m and k are other integers. The above three layers of neatly arranged equal-pitch and unequal-pitch wave windings are three winding methods, including 401, 402 in Fig. 4a, 501, 502, 503 in Fig. 5, 601, 602, 603 in Fig. 6, and Any of the 701 to 706 of 7 is limited to single or double strands arranged in layers in the slot, as shown by 202 in FIG. 2 and 102 in FIG. 1. For the above windings, the winding method is simple, and it is easy to realize automation. In addition, the shortest end optimization design is realized, the copper is saved, the leakage inductance is small, and the mid- and high-frequency performance is improved. In addition, all the wires in the slot are close to the core wall, which conducts heat well and increases the output. It should also be noted that Figures 4a, 5, 6 and 7 are rectangular tooth structures, such as

As shown in Fig. 4a, the development surface 408 of the teeth is rectangular, and at the same time, the development surface of the tile-shaped magnetic pole 407 of the rotor is also rectangular. It is said that this rotor has a straight structure between the magnetic poles and the cogging. In addition, when the rotor is a permanent magnet type, there is another type of structure with a slope between the rotor poles and the cogging as shown in FIG. 3. It can also be assembled into an oblique structure using the straight groove core shown in Figures 1 and 2. N, S are expanded views of the rotor poles, which is a rectangle, and 303 is this rectangle In the center axis of the permanent magnetic pole, 301 is the parallelogram of the tooth development plane, 304 is the middle axis of the tooth, 302 is the inclined groove, and g is the angle between 303 and 304. L is the core length and T is the tooth pitch. This structure can improve the waveform and reduce additional losses. It should also be pointed out that the main point of this oblique structure is to have a non-zero oblique angle g, that is, the cogging can still be assembled in a rectangular shape, and the development surface of the rotor poles can be made into a parallelogram, where the axis and the tooth The angle g is maintained between the central axes. Both of these oblique structures have the advantages of good harmonic performance and small additional loss. In the present invention, the optimal design of the oblique angle g should satisfy the oblique distance L * t _g g not more than 2T, which is twice the tooth moment. The second type of large-pole motor of the present invention is called a slotless type. The rotor is limited to the permanent magnet type, while the punching piece of the stator core is slotless, as shown in FIG. 8. 801 is a punched piece without a slotted iron core, the entire block is a yoke, and 802 is a cross section of a wire. The cross section of the wire is shown in the figure. In fact, the cross section of a flat wire is more effective. The wires are mounted side by side on the surface of the core against the air gap. The winding method is still based on the principle that each turn of the wire is adjacent to the core and the end is the shortest. There are also three winding methods for surface-wave windings of equal pitch and unequal pitch called single-layer. The first is a surface wave winding with no overlapping ends, the second is a surface-wound wave winding, and the third is a partially overlapping surface wave winding. The surface wave windings without overlapping at the ends are shown in FIG. 9. This figure is an expanded schematic diagram of the iron core air gap cylinder straightened in the circumferential direction. 904 is a part of the iron core cylindrical surface on the air gap side after deployment. L is the length of the core. 905 is the magnetic pole N pole and S pole of the rotor. 2 τ is the pole pitch of a pair of poles. 901, 902, and 903 are schematic illustrations of the winding method of a surface winding with k = 3 ends without overlap. They cross the core surface perpendicularly in the same direction, and the occupied surface width is B, which is the phase band width. After 901, 902, 903 are connected in series, a phase winding is formed. Fig. 10 is a single-stranded full-wave winding, and the figure shows the case of m = 2 phases. 1003 is an iron core development plan, and L is the core length. 1001 ', 1 002 are two-phase single strands The windings have the same winding method, and ^ L is a knot that is translated by half a pole pitch, that is, 90 ° phase, but overlaps at the ends, and 1004 and 1005 are overlapping positions. In the figure, the process of the 1004 overlap point is 1001 above and 1002 is pressed down. In fact, the relationship between the top and bottom can be reversed, and the process of the process of the 1005 overlap point is also the same. N and S are rotor magnetic poles, and τ is a pole pitch. However, the disadvantage of single-strand wave windings is the low surface utilization. In order to improve the surface utilization rate, the integrated method of FIG. 9 and FIG. 10 may be referred to as a method of partially overlapping end portions, that is, FIG. 9 is regarded as a phase winding as a whole to replace each phase winding 1001 or 1002 in FIG. 10. , Becomes two phases of .m-2, each phase contains k = 3 strands of conductor, and the phase band width is a surface winding of B. Its characteristic is that the k windings of each phase do not overlap at the ends, and the windings of different phases overlap at the ends. Based on this, it is not difficult to deduce the general situation of any m-phase and k-phase in each phase. The advantages of this structure are that the iron core has no slots, simple processing, and iron-saving materials; there is no cogging effect, good waveform, no noise, and stable operation. As for the magnetic circuit structure, a radial air-gap magnetic flux can be used. In the case of a permanent magnet rotor, the structure is shown in FIG. 11. 1 101 is a tile-shaped permanent magnet, an arrow 1 1 02 indicates a magnetization direction, and 1 103 is a yoke portion of a rotor core. An axial magnetic circuit structure can also be used. The structure of the motor is a disc structure. There are also a variety of magnetic pole structures to choose from. For a large number of permanent magnet intermediate frequency motors, the present invention also invents an enhanced excitation method, called a pulse excitation method of a permanent magnet motor. The power of the permanent magnet motor with the aforementioned structure can be increased by the following method:

 1. Install one or more field windings on the armature side. It is most convenient to consider one or all of the m-phase armature windings as field windings.

2. For each field winding, in each electrical cycle, a current pulse is applied at a certain moment when the permanent magnet poles on the rotor come. The generated pulse magnetic field should strengthen the rotor magnetic field. That is, the pulse current causes the permanent magnet to be instantaneously magnetized. Effects such as magnetic resistance increase the air gap magnetic flux and increase the induced potential. The situation of the generator will be described in detail today. It is well known that the exciting magnetomotive force F of an excitation-type synchronous generator leads the armature potential E on the phase plane. 90 °, as shown in Figure 12. In other words, for a certain phase winding, the fundamental wave shape of its potential is shown as E _a in FIG. 13, which reaches a positive peak at time T _{2 and} a negative peak at T ₄ , which means that the phase winding is at the zero crossing time. It is facing the rotor. The N pole, T ₃ is facing the S pole of the rotor at all times. In the case of permanent magnet synchronous generator That is, when a phase winding W _a of the FIG. 14, which is the potential of the generator E _a, the waveform shown in Figure 13, whichever is the forward current of ₁₃ as a current reference direction, then by an additional exciting circuit 1401, prior to the positive peak T in FIG i.e. 90 °, is applied to the time 13 in FIG winding W _a 14 Wing can be increased to advance the forward excitation current pulse 14 Ip in FIG. The magnetic flux in the direction of the magnetic poles achieves the purpose of strengthening the excitation. Similarly, it can be 90 after a positive peak of £ ₃ . That is, Ding in Fig. 13 _{; At the} moment, a negative pulse current-i _{p is} applied to the \ ^ winding in Fig. 14 to achieve the purpose of strengthening the excitation. In summary, a pulse excitation method of a large-pole permanent magnet synchronous motor has the structure shown in FIG. 15: 1 501 is any phase winding of the armature, G is a neutral point, and H is the other end point. Its phase potential is E _a and M is a tap of the winding, which is connected to the excitation circuit. Under normal circumstances, M can coincide with H, that is, there is no need to tap. 1502 is a discharge switch, such as a thyristor, and 1503 is a control terminal of the switch. 1504 is a charge-discharge capacitor, and 1505 is a charged DC source device. Generally speaking, it is a rectifier circuit of the phase voltage of the motor itself. 1 506 is a charging and discharging isolation device, for example, it can be a resistor or a charging and discharging isolation switch. 1507 is the direction of current flow during discharge. When the permanent magnet generator with the pulse excitation circuit of FIG. 15 is dragged, the phase potential fundamental wave is shown as the waveform of E _a in FIG. 16, and t = T ₃ is the zero-crossing time from positive to negative. Electrical angles θ = 0 °, θ ,, Θ: Phase angles at one time before and after T respectively, and the maximum value of their absolute values is 30 °. Figure 17 is the waveform s of the pulse current The parameters indicate that T _s is the start time of the pulse. The pulse excitation method shown in FIG. 15 means that at a certain time between Θ] and Θ: in FIG. 16 and FIG. 17, as shown by T _s in FIG. 17, 1503 in FIG. 15 is triggered to turn on 1502, so that The current 1507 has a pulse as shown in 1701 in FIG. 17, and its width D, that is, the electrical angle from D ₅ to the time when the current waveform drops back to 10% of the peak value does not exceed 60. . In the case of a commonly used three-phase motor, the three phase windings can be provided with an excitation device as described above, and a corresponding excitation pulse is added to each electrical cycle, which can increase the phase potential by more than 30%. In FIG. 15, the excitation current 1507 can also be made to have a reverse flow direction. At this time, the polarity of the related device should be reversed, and the starting time of the discharge should be adjusted from T in FIG. 16; The discharge reference time Θ] or T ₃ can be obtained by different methods, so as to obtain the discharge start time T _s . One method is the phase detection method, which detects the peak time or

At time 0, the appropriate T _s value between Θ and Θ ₂ can be obtained by the method of circuit delay. The peak or zero-crossing detection technology can use the existing technology. Another method is a position sensor method. A position sensor, such as a Hall device, can be embedded in the corresponding position of the stator armature winding to detect the moment when the rotor magnetic poles arrive. This is also an existing technology. In the case of a motor, the method of FIG. 15 is still effective, because when the motor enters the synchronous state, the 1 reference direction in this figure should be the opposite direction, so as long as the direction of 1507 and the timing of FIG. 17 are maintained, it still meets the When the magnetic pole comes Conditions for applying a pulsed current. The following is an example of enhanced excitation of a three-phase permanent magnet synchronous generator. It is assumed that the magnetic poles of this permanent magnet synchronous generator are shown in FIG. 11, and the stator core is shown in FIG. 1 or FIG. 2, and the windings may use any of the aforementioned equal-pitch and unequal-pitch wave windings. The phase sequence of the three-phase winding is conventionally a → b → c. The phase voltage waveforms of the two phases such as a and b are shown in FIG. 18, with phase a ahead and phase b after 120. . t is the time axis, Θ is the corresponding electrical angle, Ding, and Ding ₃ are the zero crossings of the a-phase voltage, 1801 is the equipotential point of the a and b phases, and the electrical angle is Θ: the distance from T ₃ is exactly 30. . 6, as the reference moment for the a phase winding discharge. FIG. 19 shows a charge and discharge circuit for an a-phase winding. The phase sequence of the motor is a → b — c. G is the neutral point, 1901 is the output point of phase voltage a, 1902 is the charge and discharge capacitor, 1903 is the charging power source, for convenience, you can use phase a or c as the AC power source, 1904 is the rectifier diode of the charging circuit, 1905 The charging current-limiting resistor also acts as an isolation resistor when discharging. 1906 is a thyristor switching device, 1907 is its gate, 1908 is a control voltage source, which is taken from the b-phase voltage, 1909 is a rectifier diode, and the resistance 1910 and 1911 forms a voltage divider circuit to adjust the trigger level. Resistor 1913 and Zener diode 1914 are chopper circuits, so that the 1907 gate voltage has a sufficient rise rate. Zener diode 1914 also has gate protection. 1915 is a protective capacitor. By adjusting the voltage-dividing resistor, the delay time from Θ _; to T; in FIG. 18 can be fine-tuned, that is, T _{s in} FIG. 17. The above circuit can be deduced by analogy for the other two phases, namely b and c.

18, The corresponding phase in Figure 19 can be changed to the next phase sequence. That is, phase a in the figure is replaced with phase b, phase b is replaced with phase c, and phase c is replaced with phase a. The advantages of this excitation method are that the device is simple; no brushes are needed: do not change the mechanical structure; the excitation power is very small: and the output is increased. For the first type of slot-type large pole number motor, the present invention also creates a unique electrically excited rotor structure to form a new type of large pole number intermediate frequency motor. The rotor core and windings are unfolded as shown in FIG. In the existing claw-pole type intermediate frequency motor technology, the rotor core has a concentrated magnetic circuit, so that the magnetic flux is branched to each pair of claw poles. However, in FIG. 20 of the present invention, 200 1 is a rotor core punch, N, S. are magnetic poles, τ is a pole pitch, and magnetic lines of force only pass through two adjacent poles. There is one slot per pole, and the wires in the slot are arranged neatly. Only single or double strands of each layer are allowed. According to the entire pitch wave winding method, the cross-sections of the wires in the figure 2002 and 2003 are wound according to each layer of double strands. Case of two-layer winding. 〇 and (¾ respectively indicate the direction of current flow in and out. 2004 is a schematic diagram of the stator punching. 2005 is the winding cross section in a slot. The figure shows the situation of 3 layers. Adjusting the depth of the slot can change the number of winding layers to obtain Reasonable number of excitation ampere turns. The advantages of this structure are still the simple winding method, good temperature rise performance and high efficiency.

Claims

Claim 1. A motor with a large number of poles, the rotor is a permanent magnet type or an electrically excited type or an inductive type, characterized in that the number of poles is greater than or equal to 8; the solid core wire for the armature winding is layered in the slot Neatly arranged as equal- and unequal-pitch wave windings; the windings are in slots, and each turn of the wire is adjacent to the core of the slot wall. 2. The large-pole motor according to claim 1, characterized in that the winding is a wave winding with no overlapping ends. 3. A large-pole motor as claimed in claim 1, characterized in that the windings are wave windings whose ends partially overlap. 4. The large-pole motor according to claim 1, wherein the winding is a full-wave winding. 5. The large-pole motor according to claim 1 or 2 or 3 or 4, characterized in that the armature winding is in a slot, and each layer has only a single strand of wire, and both sides of the wire are adjacent to the core of the slot wall. 6. The large-pole motor according to claim 1, 2 or 3 or 4, characterized in that the armature winding is in a slot, each layer has two strands of conductor, and each of the conductors is on the left and right sides and the slot wall core respectively. Adjacent. 7. The large-pole motor according to claim 2, characterized in that the wave windings without overlapping ends are characterized in that the number of core slots is m slots per pole; m windings in each layer form a phase winding, The m windings bypass successively adjacent m slots in the same direction without overlapping at the ends; windings of different phases are formed by translating between different layers. 8. The large-pole motor according to claim 3, characterized in that the wave windings with overlapping ends are characterized in that the number of core slots is m per pole multiplied by k slots, where m is the number of phases and k A slot is a phase band; each phase winding contains k windings, which k windings pass from one end to adjacent k slots in the same direction, and the other end crosses a pole pitch without overlapping, and then In addition, the k slots are wound back to the original end, and the overlap does not occur. The whole number of slots of the k windings can be shifted by an integer multiple of k to obtain another phase winding. According to this method, all m phases can be obtained on the same layer. Windings, and they overlap each other at the ends. 9. The large-pole number motor according to claim 4, characterized in that the whole-wave winding is a core slot with m slots per pole; m windings on each layer form m phase windings; each phase winding is Whole-wave winding; m phase windings on the same layer overlap each other at the ends. 10. The large-pole motor according to claim 1, characterized in that the rotor is an electric excitation structure type, the iron core is a straight slot structure, each slot has one slot, and the winding wires are arranged neatly in the slots. Each layer allows only a single Stranded or double-stranded solid conductors. The windings are wound with equal pitch waves. The ends do not overlap. 1 1. The large-pole motor according to claim 1, wherein the permanent magnet poles of the rotor and the stator cogging have an oblique structure, and the oblique distance and the core length L, the tooth pitch T, and the oblique angle g It should satisfy that L * t _g g is not more than 2T. 12. —A large-pole motor, characterized in that the number of poles is greater than or equal to 8: the armature core is slotless; the windings are arranged in a single layer on the surface of the core; 13. The large-pole motor according to claim 12, wherein the armature winding is a surface wave winding with non-overlapping ends, a single-phase winding including k-strand windings, and the k-strand windings are arranged side by side from the lower end. Across the core surface in the same direction, at the top The k-core wires are discharged side by side in a single layer on the surface, and the relative width occupied is the phase of the phase winding. Band width. 14. The large-pole motor according to claim 12, wherein the armature winding is a partially overlapping surface wave winding, characterized in that it has m phase windings, and each phase winding is non-overlapping at the ends. The surface wave windings of the single-phase k-strand ends have no overlap, and the windings of all m phases can be obtained, and the m phase windings overlap each other at the ends. 15. A pulse excitation method for a permanent magnet motor, which has the following characteristics:  a. One or more phase windings are set as exciting windings on the armature side, and for each exciting winding, there is a charging and discharging exciting circuit;  b. For each discharge circuit, there is a discharge trigger circuit. Its function is to make the triggering moment occur 30 times before and after the winding directly faces the magnetic pole. within. 16. The pulse excitation method for a permanent magnet motor according to claim 15, characterized in that the charge and discharge excitation circuit has a charge and discharge capacitor, and the charge and discharge process is completed once in each electric cycle: the charging circuit includes a rectifier circuit, It also contains a current-limiting resistor; the discharge circuit includes a switch and its trigger circuit; the direction of the capacitor's discharge current is the direction in which the magnetic poles are strengthened. 1 7. The pulse excitation method of a permanent magnet motor according to claim 15, wherein the trigger circuit of the discharge switch comprises a sensor of a magnetic pole position or a phase detector of a phase voltage, so as to obtain the time information of the magnetic pole arrival and generate a discharge trigger signal .