A brushless harmonic ac excited hybrid excitation synchronous machine

Abstract

The application discloses a brushless harmonic AC 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. The stator comprises a stator core and a stator winding wound on the stator core. The stator winding adopts a five-phase double-layer integer slot distribution winding. Compared with a three-phase winding, the five-phase winding has better fault tolerance. The rotor comprises a rotor core and a built-in one-word permanent magnet. The five-phase hybrid excitation permanent magnet synchronous motor realizes electric excitation by using a fundamental wave, and a third harmonic wave is used as a working harmonic wave of the motor. Compared with a conventional hybrid excitation permanent magnet synchronous motor, only one set of winding is needed, and the rotor adopts a hybrid excitation mode combining permanent magnet excitation and AC electric excitation. Therefore, the motor has the characteristics of avoiding the brush and slip ring required by the conventional rotor DC excitation, being more reliable in operation, being convenient in air gap magnetic field adjustment, being easy in fault de-excitation, being high in efficiency, being high in power density, and being strong in fault tolerance.

Description

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 includes a stator and a rotor disposed inside the stator; the stator includes 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 includes: a rotor core with multiple I-shaped permanent magnet slots; multiple permanent magnets, all of which are I-shaped structures, 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: 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 This is a two-dimensional plan view of the present invention.

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

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

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

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

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

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

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

[0020] The following is combined Figures 1 to 7The specific embodiments of the present invention will be described in detail below. 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 are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of 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] Example 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] like Figure 1 As shown, 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 5 and multiple permanent magnets 3. The rotor core 5 has multiple built-in slots for the permanent magnets. Each permanent magnet 3 has a linear structure and is positioned one-to-one within a slot on the rotor core 5. The permanent magnets 3 are connected in series via magnetic circuits. Figure 1 As shown, four slots for permanent magnets are cut into the rotor core 5 to form four permanent magnet poles; the two unslotted parts of the rotor core 5 constitute two electrically excited poles; the four permanent magnet poles and the two electrically excited poles divide the rotor core 5 into six equal parts. 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.

[0025] like Figure 2 As shown, rectangular slots 4 are provided on the pole face of the rotor core 5 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] like Figure 2 The diagram shown is 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] like Figure 3 and Figure 4 The diagram shows 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] like Figure 5 The diagram shows the magnetic circuit of the five-phase hybrid excitation permanent magnet synchronous motor in this embodiment. As can be seen, 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 form a three-pair magnetic field, which interacts with the third harmonic magnetic field applied to the stator windings 2 to generate torque.

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

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

[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, Includes a stator and a rotor disposed inside the stator; The stator includes 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, 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 slots for permanent magnets; multiple permanent magnets, all of which are of a single-line structure, and the multiple permanent magnets are arranged one-to-one in the multiple slots for permanent magnets, and the multiple permanent magnets are connected by a series magnetic circuit. 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. 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.

2. The brushless harmonic AC excitation hybrid excitation synchronous motor according to claim 1, characterized in that, The stator winding is simultaneously supplied with fundamental current and 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-pole rotating magnetic field; By adjusting the phase and amplitude of the fundamental current, the resulting pair of magnetic fields superimposed on the magnetic field generated by the permanent magnet together form three pairs of magnetic fields in the air gap. The three pairs of magnetic fields interact with the three pairs of rotating magnetic fields generated by the third harmonic current to generate electromagnetic torque.

3. The brushless harmonic AC excitation hybrid excitation synchronous motor according to claim 1, characterized in that, The hybrid excitation synchronous motor has 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.

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