CN102801268A - Low-inductance low loss PMSM - Google Patents

Abstract

A low-inductance and low-loss permanent magnet synchronous motor relates to the technical field of a new structure low-inductance and low-loss permanent magnet synchronous motor. In order to solve the problem that the motor in the prior art has too high inductance, which is not conducive to the high-speed operation of the motor, and thus generates magnetic saturation of the core material to increase the core loss. The invention provides a low-inductance and low-loss permanent magnet synchronous motor, comprising a rotating shaft (1), a permanent magnet rotor (2), a stator (3), an upper end cover (4), a lower end cover (5), a bearing (6), and a shell body (7), the permanent magnet rotor (2) includes a rotor core (21) and a permanent magnet (22), the stator (3) includes a stator core (31), and a single-phase or multi-phase stator is radially wound on the stator core (31) Windings (32), stator windings (32) are arranged circumferentially, and each phase winding in the stator windings (32) includes one or more pairs of adjacent two coils, and the distance between adjacent two coils is a pole pitch and wound in the opposite direction. The invention can be applied to many different flywheel energy storage occasions.

Description

A Low Inductance and Low Loss Permanent Magnet Synchronous Motor

technical field

The invention discloses a low-inductance and low-loss permanent magnet synchronous motor, which relates to the technical field of a new structure low-inductance and low-loss permanent magnet synchronous motor.

Background technique

The energy issue is one of the major issues facing mankind in the 21st century. While constantly developing new energy sources, advanced energy-saving technologies and energy storage technologies need to be developed in order to utilize existing energy sources more effectively. Among energy storage technologies, flywheel energy storage has high energy density, high power density, high energy conversion rate (about 90%), long service life, short charging time, adaptability to various environments, repeatable deep discharge, and simple maintenance. The advantages of green and environmental protection have broad application prospects and are also research hotspots in recent years. Among them, the motor/generator is the core component to complete energy conversion, and it is also the key to realize the conversion of mechanical energy and electrical energy. Because of the above characteristics of the flywheel, the flywheel system has very high requirements for the motor/generator system, and the flywheel motor needs to have high operating speed, wide speed range, extremely low no-load loss, and high conversion efficiency. The problem commonly encountered at present is that the excessively high inductance is not conducive to the high-speed operation of the motor, and thus the magnetic saturation of the core material will increase the core loss.

Contents of the invention

In order to solve the problem of high-speed operation of the motor due to the excessively high inductance of the prior art motor, and thus increase the core loss due to magnetic saturation of the core material, the present invention provides a low-inductance and low-loss permanent magnet synchronous motor. The motor includes a rotating shaft , a permanent magnet rotor, a stator, an upper end cover, a lower end cover, a bearing, and a housing, wherein the permanent magnet rotor includes a rotor core and a permanent magnet, and the permanent magnet includes a plurality of N and S poles, and the N and S poles are staggered Arranged or arranged opposite to each other with the same polarity, the permanent magnets are placed on the surface of the rotor core or built into the rotor core. The stator includes a stator core, and single-phase or multi-phase stator windings are wound radially on the stator core, and the stator windings are arranged in a circumferential direction. , each phase winding in the stator winding includes one or more pairs of two adjacent coils, the distance between the two adjacent coils is a pole pitch and the winding directions are opposite.

Referring to Fig. 9, the working principle of the present invention is illustrated:

As shown in Figure 9, when considering dismantling the double-wire non-inductive coil and placing the permanent magnet under the coil, it is assumed that the permanent magnet moves to the left. If the coils AB and A1B1 are closed, the current in the direction of A to B will be generated in the coil AB, and the magnetic flux from left to right will be generated in the iron core (the left dashed arrow in the figure), and the current in the direction of A1 to B1 will be generated in the coil A1B1 current, and generate a magnetic flux from right to left in the iron core (the right dotted arrow in the figure), if the B terminal of the two coils is connected to the B1 terminal, the current direction is from A to A1 in the new coil AA1, and the coil The total magnetic flux of AA1 is greatly reduced due to mutual cancellation, which makes the inductance of the coil AA1 extremely low, and at the same time, the iron core will not be saturated due to the increase of the current in the coil AA1, thereby reducing the core loss. The principle at this time is similar to the power generation state of the permanent magnet synchronous motor, so it is feasible to design a low inductance and low iron loss permanent magnet motor based on this principle.

The beneficial effect of the present invention is to propose a low-inductance and low-loss permanent magnet synchronous motor. By rationally configuring the winding and designing the magnetic circuit structure, the magnetic flux generated by the current in the motor armature can be effectively offset. On the one hand, an extremely low inductance can be obtained. The motor is easier to run at high speed; on the other hand, the magnetic saturation of the core material can be reduced to obtain extremely low core loss. The scheme proposed by the invention helps to improve the performance of high-speed, low-loss, high-efficiency motors used in flywheel energy storage systems, and has important theoretical and practical significance for the research and development of low-inductance and low-loss permanent magnet synchronous motors with this new structure.

Description of drawings

Fig. 1 is a schematic diagram of the axial sectional structure of the motor of the first embodiment; Fig. 2 is a schematic diagram of the sectional structure of the motor of the first embodiment along the A-A direction in Fig. 1; Fig. 3 is a winding of the motor of the first embodiment Schematic diagram of the connection structure; Fig. 4 is a schematic diagram of the structure of the motor of the second specific embodiment at the same position as Fig. 2; Fig. 5 is a schematic structural diagram of the motor of the third specific embodiment; Fig. 6 is a section in the B-B direction of the motor of the third embodiment Schematic diagram of the structure; FIG. 7 is a schematic cross-sectional structure diagram of the motor in the third embodiment in the C-C direction, and FIG. 8 is a schematic structural diagram of the motor in the fourth embodiment. Fig. 9 is a schematic diagram of the working principle of the present invention.

Detailed ways

Embodiments of the present invention will be described in detail below with reference to FIG. 1 to FIG. 8 .

Embodiment 1: As shown in Figures 1 and 2, a low-inductance and low-loss permanent magnet synchronous motor includes a rotating shaft 1, a permanent magnet rotor 2, a stator 3, an upper end cover 4, a lower end cover 5, a bearing 6, and a housing 7. It is characterized in that the permanent magnet rotor 2 includes a rotor core 21 and a permanent magnet 22. The permanent magnet 22 includes a plurality of N and S poles. On the surface of the rotor core 21 or built into the rotor core 21, the stator 3 includes a stator core 31 on which a single-phase or multi-phase stator winding 32 is radially wound, the stator winding 32 is arranged in a circumferential direction, and the stator winding 32 Each phase winding includes one or more pairs of two adjacent coils, the distance between the two adjacent coils is a pole pitch and the winding directions are opposite. The stator core 31 is made of laminated silicon steel sheets. The stator core 31 is a concentric ring structure. The stator core 31 may be a slotted structure.

As shown in Figure 3. When the motor is used as a motor, current is passed through the winding, or it is used as a generator to send current to the load, the direction of the magnetic flux generated by the armature current in the armature core under different polarities is opposite, if the coils under different polarities have For the same number of turns, the generated magnetic fluxes are equal in size and opposite in direction, and then the magnetic fluxes generated by the armature current in the phase winding cancel each other out. Ideally, the total magnetic flux generated by the armature current in the armature core is zero, which can be Obtain very low inductance per phase. At the same time, when the load changes, the armature core will not be saturated due to the increase of current, thus effectively reducing the loss of the stator core.

Embodiment 2: As shown in FIG. 4 , the difference between this embodiment and Embodiment 1 is that the permanent magnet rotor 2 includes two rotors, an inner rotor and an outer rotor, the inner rotor includes an inner rotor core 211 and an inner rotor permanent magnet 221, and the outer rotor includes The outer rotor core 212 and the outer rotor permanent magnet 222, the inner and outer rotors have the same number of poles, and the stator 3 is located between the inner rotor and the outer rotor. The stator winding is the same as that of Embodiment 1. In addition to the characteristics of Embodiment 1, this embodiment can effectively increase the torque of the motor by using the inner and outer windings of the stator.

Specific embodiment three: as shown in Fig. 5, Fig. 6 and Fig. 7, the difference between this embodiment and the above embodiments is that the rotor core 21 is a disc structure, the stator 3 and the rotor 2 are axially arranged, and the stator core 31 is made of silicon steel The stator core 31 is a concentric ring structure. A stator winding 32 is placed on the stator core, and its winding method and arrangement rules are the same as those in the first embodiment. The rotor magnetic field interacts with the stator current to generate torque, and the arrangement of the windings makes the motor have extremely low inductance and low core loss.

Embodiment 4: As shown in Figure 8, the difference between this embodiment and Embodiment 3 is that the number of permanent magnet rotors 2 of the motor is multiple, and all permanent magnet rotors 2 are axially connected, and every two adjacent permanent magnet rotors A stator 3 is arranged between the 2. Except that the rotor at the left and right ends only interacts with the stator on one side, the middle rotor interacts with the stators on both sides respectively, and the two sides of the stator winding also interact with the rotor magnetic fields on both sides at the same time. Each unit is the same as Embodiment 3, and the axes of different units To meet different power requirements and different torque requirements, this embodiment has the advantages of Embodiment 1 at the same time.

Claims (6)

1. A low-inductance and low-loss permanent magnet synchronous motor, including a shaft (1), a permanent magnet rotor (2), a stator (3), an upper end cover (4), a lower end cover (5), a bearing (6), and a housing (7), characterized in that the permanent magnet rotor (2) includes a rotor core (21) and a permanent magnet (22), the permanent magnet (22) includes a plurality of N and S poles, and the N and S poles are alternately arranged or The same polarity is arranged facing each other, the permanent magnet (22) is placed on the surface of the rotor core (21) or built in the rotor core (21), the stator (3) includes the stator core (31), and the upper diameter of the stator core (31) Winding single-phase or multi-phase stator windings (32), the stator windings (32) are circumferentially arranged, and each phase winding in the stator windings (32) includes one or more pairs of adjacent two coils, and the adjacent two The coils are one pole apart and wound in opposite directions. 2. The low-inductance and low-loss permanent magnet synchronous motor according to claim 1, characterized in that: the stator core (31) is made of laminated silicon steel sheets, and the stator core (31) is a concentric ring structure. 3. The low-inductance and low-loss permanent magnet synchronous motor according to claim 2, characterized in that: the stator core (31) is a slotted structure. 4. The low-inductance and low-loss permanent magnet synchronous motor according to claim 1, characterized in that: the permanent magnet rotor (2) includes two rotors, inner and outer, and the inner rotor includes an inner rotor core (211) and an inner rotor The permanent magnet (221), the outer rotor includes the outer rotor iron core (212) and the outer rotor permanent magnet (222), the inner and outer rotors have the same number of poles, and the stator (3) is located between the inner rotor and the outer rotor. 5. The low-inductance and low-loss permanent magnet synchronous motor according to claim 1, characterized in that: the rotor core (21) is a disc structure, the stator (3) and the rotor (2) are axially arranged, and the stator core (31) is rolled from silicon steel sheets, and the stator core (31) is a concentric ring structure. 6. The low-inductance and low-loss permanent magnet synchronous motor according to claim 5, characterized in that: the number of the permanent magnet rotors (2) is multiple, and all the permanent magnet rotors (2) are axially connected, every two A stator (3) is arranged between two adjacent permanent magnet rotors (2).

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