Brushless harmonic alternating current excitation hybrid excitation synchronous motor

Abstract

The invention discloses a brushless harmonic alternating current excitation hybrid excitation synchronous motor, and relates to the technical field of multiphase motors, the motor comprises a stator and a rotor arranged in the stator, and the stator comprises a stator iron core and a stator winding wound on the stator iron core; the stator winding adopts a five-phase double-layer integer slot distribution winding, and compared with a three-phase winding, the five-phase winding has better fault-tolerant capability. The rotor comprises a rotor iron core and a built-in linear permanent magnet. According to the five-phase hybrid excitation permanent magnet synchronous motor, electric excitation is achieved through fundamental waves, and third harmonic waves serve as working harmonic waves of the motor. Compared with a traditional hybrid excitation permanent magnet synchronous motor, only one set of winding is needed, the rotor adopts a hybrid excitation mode combining permanent magnet excitation and alternating current excitation, an electric brush and a sliding ring needed by traditional rotor direct current excitation are avoided, operation is more reliable, and the service life of the motor is prolonged. And meanwhile, the device has the characteristics of convenience in air-gap magnetic field adjustment, easiness in fault field suppression, high efficiency, high power density and strong fault-tolerant capability.

Description

A hybrid excitation synchronous motor with brushless harmonic AC excitation Technical Field

[0001] This invention relates to the field of multiphase motor technology, specifically a brushless harmonic AC excitation hybrid excitation synchronous motor. Background Technology

[0002] The hybrid-excitation permanent magnet synchronous motor combines the advantages of both permanent magnet synchronous motors and electrically excited synchronous motors. It fully leverages the significant advantages of permanent magnet synchronous motors, such as superior operating efficiency and power density, achieved through high-performance permanent magnet excitation, while retaining the flexibility of electrically excited synchronous motors in controlling the magnetic field by adjusting the excitation current. The hybrid-excitation permanent magnet synchronous motor exhibits high convenience in air gap magnetic field adjustment, easily strengthening or weakening the air gap magnetic field by precisely controlling the magnitude and direction of the excitation current, allowing the motor to maintain optimal performance under various operating conditions. Furthermore, the hybrid-excitation permanent magnet synchronous motor is equipped with an independent electrically excited system, enabling rapid and reliable demagnetization in the event of a motor failure, effectively preventing the fault from escalating. Meanwhile, this hybrid excitation structure also inherits the high efficiency characteristics of permanent magnet motors, maintaining a competitive advantage in power density. In summary, the hybrid excitation permanent magnet synchronous motor combines a permanent magnet synchronous motor with an electrically excited synchronous motor, fully leveraging the high efficiency and high density advantages of permanent magnet synchronous motors due to permanent magnet excitation, as well as the adjustable excitation current advantage of electrically excited synchronous motors. It features convenient air gap magnetic field adjustment, easy fault demagnetization, high efficiency, high power density, and strong fault tolerance, making it a promising candidate for applications in fields with extremely high motor performance requirements, such as new energy vehicles and aerospace.

[0003] Currently, the excitation methods for electrically excited synchronous motors mainly include rotor DC excitation and stator AC excitation. Rotor DC excitation inevitably relies on a mechanical contact current collector device consisting of slip rings and carbon brushes. Continuous mechanical friction leads to carbon brush wear, and the resulting carbon dust requires regular cleaning. Furthermore, under high-speed or vibration conditions, poor contact can easily generate electrical sparks, posing a potential safety hazard. Simultaneously, mechanical friction itself consumes some useful work, reducing the overall system efficiency. Therefore, this mechanical energy transfer method of rotor DC excitation contradicts the development trend of maintenance-free, high-efficiency brushless motors. While stator AC excitation achieves brushlessness, it typically requires an additional independent excitation winding embedded within the already limited stator slots. This directly forces the main armature winding and the excitation winding to share a limited slot area, potentially reducing the conductor cross-sectional area of ​​both, thereby increasing copper losses and reducing electromagnetic load capacity and efficiency. This fundamentally restricts the optimal layout of winding materials and reduces the utilization rate of stator slots and windings. Summary of the Invention

[0004] The purpose of this invention is to provide a brushless harmonic AC excitation hybrid excitation synchronous motor to solve the above-mentioned problems.

[0005] The technical solution of this invention is: a brushless harmonic AC excitation hybrid excitation synchronous motor, comprising a stator and a rotor disposed inside the stator; the stator comprises a stator core and stator windings; the stator windings are wound on the stator core and adopt a five-phase double-layer integer slot distribution winding, the five-phase double-layer integer slot distribution windings are star-connected, the pitch is 10, the number of pole pairs is 1, the number of slots per pole per phase is 2, and the selection of the number of slots and poles of the five-phase double-layer integer slot distribution windings is based on maximizing the fundamental winding factor and the third harmonic winding factor; the rotor comprises: a rotor core, having multiple I-shaped permanent magnet slots; multiple permanent magnets, all of which are I-shaped structures, the multiple permanent magnets are arranged one-to-one in the multiple I-shaped permanent magnet slots, and the multiple permanent magnets are connected by a series magnetic circuit.

[0006] Furthermore, four slots for permanent magnets are cut into the rotor core to form four permanent magnet poles; the two unslotted parts of the rotor core constitute two electrically excited poles; the four permanent magnet poles and the two electrically excited poles divide the rotor core into six equal parts, and the excitation of the motor is adjusted by adjusting the electrically excited poles, thus solving the problem of the non-adjustable excitation of the permanent magnet motor.

[0007] Furthermore, rectangular slots are provided on the pole face of the rotor core that constitutes the electrically excited magnetic poles to adjust the pole arc coefficient of the electrically excited magnetic poles so that it is similar to the pole arc coefficient of the permanent magnet poles, so that the magnetic field generated by the electrically excited and permanent magnet excitation is symmetrical.

[0008] Furthermore, the stator winding is simultaneously supplied with a fundamental current and a third harmonic current; through the five-phase double-layer integer slot distributed winding, the fundamental current generates a pair of rotating magnetic fields that rotate synchronously with the rotor; through the five-phase double-layer integer slot distributed winding, the third harmonic current generates a three-pair rotating magnetic field, which is used to generate stable torque; by adjusting the phase and amplitude of the fundamental current, the pair of magnetic fields it generates are superimposed with the magnetic field generated by the permanent magnet, together forming a three-pair magnetic field in the air gap. The three-pair magnetic field interacts with the three-pair rotating magnetic field generated by the third harmonic current to generate electromagnetic torque, thereby realizing the drive of the brushless harmonic AC excitation hybrid excitation synchronous motor.

[0009] Furthermore, the permanent magnet synchronous motor is equipped with only one set of five-phase double-layer integer slot distributed windings, which simultaneously achieves excitation regulation and torque generation by injecting currents with different harmonic components.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows: The five-phase hybrid excitation permanent magnet synchronous motor of the present invention adopts a five-phase double-layer integer slot distributed winding. Compared with the traditional hybrid excitation permanent magnet synchronous motor, only one set of windings is required, and the winding utilization rate is higher. Moreover, the rotor adopts a hybrid excitation method that combines permanent magnet excitation and AC excitation, which fully utilizes the high efficiency and high density advantages brought by permanent magnet excitation of permanent magnet synchronous motor, as well as the advantage of adjustable excitation current of AC excitation synchronous motor. It avoids the brushes and slip rings required by traditional rotor DC excitation, making the operation more reliable. At the same time, it has the characteristics of convenient air gap magnetic field adjustment, easy fault demagnetization, high efficiency, high power density, and strong fault tolerance.

[0011] This invention features rectangular slots in the rotor's electrically excited poles to adjust the pole arc coefficient, resulting in a uniform six-pole magnetic field in the air gap. A fundamental wave is introduced into the stator windings; by adjusting the phase of the fundamental wave, a six-pole magnetic field is formed in the air gap between the electrically excited poles and the permanent magnet poles. The introduction of a third harmonic generates a rotating magnetic field with three pairs of poles, which interacts with the magnetic field generated by the permanent magnet and the electrically excited poles to produce a constant electromagnetic torque. Compared to traditional three-phase motors, this invention employs a phase redundancy design, resulting in better fault tolerance. Even in the event of a single-phase short circuit, the motor can still operate normally through fault-tolerant control. Attached Figure Description

[0012] Figure 1 is a two-dimensional plan view of the present invention.

[0013] Figure 2 is a stator winding wiring diagram of the present invention.

[0014] Figure 3 is a magnetomotive force diagram of the stator winding of the present invention.

[0015] Figure 4 is a spectrum distribution diagram of the stator winding of the present invention.

[0016] Figure 5 is a schematic diagram of the magnetic pole circuit of the present invention.

[0017] Figure 6 shows the air gap magnetic flux density waveform when the permanent magnet of the present invention is energized.

[0018] Figure 7 is a waveform diagram of the air gap magnetic flux density when the permanent magnet and the electric excitation are energized together.

[0019] Among them, 1. stator core, 2. stator winding, 3. permanent magnet, 4. rotor core, and 5. rectangular slot. Detailed Implementation

[0020] The specific embodiments of the present invention will be described in detail below with reference to Figures 1 to 7. In the description of the present invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0021] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0022] An embodiment of a brushless harmonic AC excitation hybrid excitation synchronous motor includes a stator and a rotor, and adopts an internal rotor structure, with the rotor placed inside the stator.

[0023] As shown in Figure 1, the stator includes a stator core 1 and a stator winding 2. The stator winding 2 is wound on the stator core 1 and adopts a five-phase double-layer integer slot distribution winding. The five-phase double-layer integer slot distribution winding is connected in a star configuration with a pitch of 10, a pole pair number of 1, and a slot number of 2 per pole per phase. The selection of the number of slots and poles of the five-phase double-layer integer slot distribution winding is based on maximizing the fundamental winding factor and the third harmonic winding factor.

[0024] The rotor includes a rotor core 4 and multiple permanent magnets 3. The rotor core 4 has multiple built-in I-shaped permanent magnet slots. The multiple permanent magnets 3 are all I-shaped structures, and each permanent magnet 3 is arranged in a one-to-one correspondence within one of the I-shaped permanent magnet slots on the rotor core 4. The multiple permanent magnets 3 are connected in series by a magnetic circuit, as shown in Figure 1. There are four I-shaped permanent magnet slots on the rotor core 4 to form four permanent magnet poles. The two unslotted parts on the rotor core 4 constitute two electrically excited poles. The four permanent magnet poles and the two electrically excited poles divide the rotor core 4 into six equal parts. The excitation of the motor is adjusted by adjusting the electrically excited poles, which solves the problem of the non-adjustable excitation of the permanent magnet motor.

[0025] As shown in Figure 2, rectangular slots 5 are provided on the pole face of the rotor core 4 that constitutes the electrically excited magnetic poles. These slots are used to adjust the pole arc coefficient of the electrically excited magnetic poles so that it is close to the pole arc coefficient of the permanent magnet poles, thereby making the magnetic field generated by the electrically excited permanent magnet excitation symmetrical.

[0026] The stator winding 2 is simultaneously supplied with the fundamental current and the third harmonic current.

[0027] Through a five-phase double-layer integer slot distributed winding, the fundamental current generates a pair of rotating magnetic fields that rotate synchronously with the rotor.

[0028] The third harmonic current generates a three-pole rotating magnetic field through a five-phase double-layer integer slot distributed winding, which is used to generate a stable torque.

[0029] By adjusting the phase and amplitude of the fundamental current, the resulting pair of pole magnetic fields are superimposed with the magnetic field generated by the permanent magnet 3, forming three pairs of pole magnetic fields in the air gap. The three pairs of pole magnetic fields interact with the three pairs of rotating magnetic fields generated by the third harmonic current to generate electromagnetic torque, thereby realizing the drive of the brushless harmonic AC excitation hybrid excitation synchronous motor.

[0030] The permanent magnet synchronous motor has only one set of five-phase double-layer integer slot distributed windings, which can simultaneously achieve excitation regulation and torque generation by injecting current with different harmonic components.

[0031] Figure 2 shows the stator winding wiring diagram of the five-phase 20-slot 2-pole hybrid excitation permanent magnet synchronous motor in this embodiment. It adopts an integer slot distribution winding with 2 slots per pole per phase.

[0032] Figures 3 and 4 show the magnetomotive force and spectrum distribution of the stator winding of the five-phase 20-slot 2-pole hybrid excitation permanent magnet synchronous motor in this embodiment. The winding has 2 slots per pole per phase, and the magnetomotive force has good sinusoidal characteristics. As can be seen from the spectrum, the order of the main harmonic is equal to the number of pole pairs. This harmonic is called the fundamental wave. The winding factors of the fundamental wave and the third harmonic of this winding are relatively high, at 0.987 and 0.891 respectively, which indicates that it has higher electromagnetic conversion efficiency.

[0033] Figure 5 shows a schematic diagram of the magnetic circuit of the five-phase hybrid excitation permanent magnet synchronous motor in this embodiment. As can be seen from the figure, the motor is jointly excited by the permanent magnets 3 and the stator windings 2. The four permanent magnets 3 generate two pairs of magnetic fields, while the stator windings 2, through which a fundamental alternating current is applied, generate one pair of magnetic fields. The permanent magnets 3 and the electrical excitation together constitute a three-pair magnetic field, which interacts with the third harmonic magnetic field applied to the stator windings 2 to generate torque.

[0034] Figure 6 shows the air gap magnetic flux density waveform when the permanent magnet of the five-phase hybrid excitation permanent magnet synchronous motor in this embodiment is energized. It can be seen from the air gap magnetic flux density waveform that the air gap magnetic flux density at this time is a magnetic field with two pairs of poles.

[0035] Figure 7 shows the air gap magnetic flux density waveform of the five-phase hybrid excitation permanent magnet synchronous motor in this preferred embodiment when the permanent magnet and the electric excitation are jointly energized. It can be seen from the air gap magnetic flux density waveform that the air gap magnetic flux density is a magnetic field with three pairs of poles and good symmetry.

[0036] This embodiment provides a brushless harmonic AC-excited hybrid excitation synchronous motor. The stator winding adopts a five-phase, double-layer, integer-slot distributed winding. Compared with traditional hybrid excitation permanent magnet synchronous motors, only one set of windings is required, resulting in higher winding utilization. The rotor employs a hybrid excitation method combining permanent magnet excitation and AC excitation, fully leveraging the high efficiency and high density advantages of permanent magnet synchronous motors (due to permanent magnet excitation) and the adjustable excitation current of AC-excited synchronous motors. It features convenient air gap magnetic field adjustment, easy fault demagnetization, high efficiency, high power density, and strong fault tolerance.

[0037] The above-disclosed embodiments are merely preferred embodiments of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A hybrid excitation synchronous motor with brushless harmonic AC excitation, characterized in that, The system includes a stator and a rotor located inside the stator. The stator includes a stator core and stator windings. The stator windings are wound around the stator core and are a five-phase double-layer integer slot distribution winding. The five-phase double-layer integer slot distribution windings are star-connected with a pitch of 10, a pole pair number of 1, and a slot number of 2 per pole per phase. The selection of the number of slots and poles of the five-phase double-layer integer slot distribution windings is based on maximizing the fundamental winding factor and the third harmonic winding factor. The rotor includes: a rotor core with multiple I-shaped permanent magnet slots; multiple permanent magnets, all of which are I-shaped structures, and the multiple permanent magnets are arranged one-to-one in the multiple I-shaped permanent magnet slots, and the multiple permanent magnets are connected by a series magnetic circuit.

2. The brushless harmonic AC excitation hybrid excitation synchronous motor according to claim 1, characterized in that, The rotor core has four slots for permanent magnets to form four permanent magnet poles; the two unslotted parts of the rotor core constitute two electrically excited poles; the four permanent magnet poles and the two electrically excited poles divide the rotor core into six equal parts.

3. The brushless harmonic AC excitation hybrid excitation synchronous motor according to claim 2, characterized in that, Rectangular slots are provided on the pole face of the rotor core that constitutes the electrically excited magnetic poles, so as to adjust the pole arc coefficient of the electrically excited magnetic poles to be similar to that of the permanent magnet magnetic poles.

4. The brushless harmonic AC excitation hybrid excitation synchronous motor according to claim 1, characterized in that, The stator winding is simultaneously supplied with a fundamental current and a third harmonic current. Through the five-phase double-layer integer slot distributed winding, the fundamental current generates a pair of rotating magnetic fields that rotate synchronously with the rotor. Through the five-phase double-layer integer slot distributed winding, the third harmonic current generates a three-pair rotating magnetic field. By adjusting the phase and amplitude of the fundamental current, the pair of magnetic fields it generates are superimposed with the magnetic field generated by the permanent magnet, forming a three-pair magnetic field in the air gap. The three-pair magnetic fields interact with the three-pair rotating magnetic field generated by the third harmonic current to generate electromagnetic torque.

5. The brushless harmonic AC excitation hybrid excitation synchronous motor according to claim 1, characterized in that, The permanent magnet synchronous motor has only one set of five-phase double-layer integer slot distributed windings, and excitation regulation and torque generation are achieved simultaneously by injecting current with different harmonic components.

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