Dual-stator hybrid-excitation alternating-pole brushless doubly-fed machine

Abstract

The present invention discloses a double-stator hybrid excitation alternating-pole brushless doubly-fed motor, comprising an outer stator, an inner stator and a rotor, wherein the outer stator is provided with a pole pair number of p. p The power winding is arranged on the inner stator with a pole pair number of p c The control winding is provided on the outer stator, and a set of power winding is provided on the inner stator. The number of pole pairs of the power winding and the control winding meets p p =3p c , 2p c A permanent magnet is embedded in the rotor, and the thickness of the permanent magnet is the same as that of the rotor; the permanent magnet on the rotor is single polarity, and the speed of the magnetic field generated by the inner and outer stator windings meets the 60f rotation speed of the rotor. p / p p =60f c / p c =n. The motor of the present invention combines the advantages of high efficiency of a permanent magnet motor and high permanent magnet utilization of an alternating pole motor. Furthermore, the air gap magnetic field of the motor can be adjusted by changing the excitation magnitude of the control winding, thereby increasing the voltage regulation range of the motor. Furthermore, the motor is easy to manufacture, uses a small amount of permanent magnets, and has a low manufacturing cost.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a double-stator hybrid excitation alternating-pole brushless doubly-fed motor. Background Art

[0002] AC excitation brushless doubly-fed motor is suitable for variable speed constant frequency power generation and variable frequency speed regulation system. Its characteristics are small capacity of inverter required for system operation and reliable operation.

[0003] Existing brushless doubly-fed motors can be divided into three categories based on their rotor structure: reluctance, cage, and wound-type. The presence of cage bars or windings in cage and wound-type brushless doubly-fed motors increases rotor-side losses, resulting in lower motor efficiency. Reluctance rotor brushless doubly-fed motors offer relatively high efficiency, but their magnetomotive force harmonics are high, resulting in lower power density and performance that fails to meet industrial application requirements.

[0004] Permanent magnet motors (PMMs) offer numerous advantages, including high efficiency, high power density, and a simple structure. They have been widely used in aerospace, household appliances, wind power generation, and electric vehicles. However, PMMs suffer from the difficulty of regulating the air gap magnetic field. To effectively address this issue, many experts and scholars have proposed hybrid excitation motors, based on PMMs, that use the electromagnetic excitation magnetomotive force to assist in regulating the air gap magnetic field. However, some existing hybrid excitation motors have brush structures, resulting in low reliability. Furthermore, the structure also uses an excessive amount of permanent magnets. The high price of rare earth materials increases the manufacturing and subsequent maintenance costs of these motors, hindering their large-scale promotion and use. Summary of the Invention

[0005] The embodiment of the present invention provides a dual-stator hybrid excitation alternating-pole brushless doubly-fed motor, which solves the reliability problem, reduces the motor cost, and improves the power density and efficiency.

[0006] In order to solve the above technical problems, the present invention proposes a dual-stator hybrid excitation alternating-pole brushless doubly-fed motor, comprising:

[0007] An outer stator, an inner stator and a rotor, wherein the outer stator is provided with a pole pair number of The power winding is arranged on the inner stator with a pole pair number of The control winding of the outer stator is provided with a set of power windings; the inner stator is provided with a set of control windings, and the number of pole pairs of the power windings and the control windings meets , A permanent magnet is embedded in the rotor, and the thickness of the permanent magnet is the same as that of the rotor; the permanent magnet on the rotor is single polarity, and the speed of the magnetic field generated by the inner and outer stator windings meets the rotor speed. , that is, the frequencies of the inner and outer stator windings meet .

[0008] Furthermore, the direction of the magnetic field formed by the control winding is directly opposite to the axis of the ferromagnetic pole, and the air gap magnetic field is adjusted by changing the magnitude of the control winding excitation.

[0009] The permanent magnets are installed in the rotor at intervals by embedding and show the same polarity to the outside. The mechanical angle of the ferromagnetic poles with a small circumference between two adjacent permanent magnets is .

[0010] The number of slots of the outer stator slots and the inner stator slots is equal or unequal.

[0011] The number of the permanent magnets is the same as the number of control winding poles, both of which are The rotor adopts axial lamination and has no brush device on the rotor side, which has high reliability.

[0012] The advantages of the present invention are that: the present invention adopts permanent magnets embedded in the rotor, showing the same polarity (both are N or S ), the mechanical angle of the ferromagnetic pole with the smallest circumference between two adjacent permanent magnets is , the thickness of the permanent magnet is the same as the thickness of the rotor, and the number of permanent magnets is the same as the number of control winding poles, both The rotor utilizes axial laminations and a brushless rotor mechanism for high reliability. This motor combines the high efficiency of permanent magnet motors with the high permanent magnet utilization of alternating-pole motors. It also allows the air gap magnetic field to be adjusted by varying the excitation level of the control winding, thereby increasing the motor's voltage regulation range. Furthermore, it is easy to process, uses fewer permanent magnets, and offers low manufacturing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a structural diagram of the double-stator hybrid excitation alternating-pole brushless doubly-fed motor newly proposed by the present invention;

[0014] Figure 2 This is a structural diagram of the outer stator of the brushless doubly-fed motor when the number of outer stator slots is 36.

[0015] Figure 3 This is a diagram of the inner stator structure of the brushless doubly-fed motor when the number of inner stator slots is 24;

[0016] Figure 4 This is a brushless doubly-fed motor rotor structure diagram when the number of power winding pole pairs is 3 and the number of control winding pole pairs is 1;

[0017] Figure 5 The magnetic field line distribution of the double-stator hybrid excitation alternating-pole brushless doubly-fed motor newly proposed by the present invention at a certain moment;

[0018] Figure 6 is the rotor speed The waveform of the power winding output voltage and its Fourier analysis when the motor is under a certain load;

[0019] Figure 7 is the rotor speed When the motor load remains unchanged, the relationship between the power winding output voltage and the control winding excitation current is shown. DETAILED DESCRIPTION

[0020] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0021] Figure 1 The permanent magnet double-stator brushless doubly-fed motor newly proposed by the present invention comprises an outer stator core 1 and an inner stator core 2. The outer stator core 1 is provided with a pole pair number of The power winding 4 has a pole pair number of The frequency of the current passing through the control winding 5 and the power winding 4 is , the frequency of the current passing through the control winding 5 is ;The rotor speed is , a set of power windings 4 is provided on the outer stator; a set of control windings 5 is provided on the inner stator; the number of pole pairs of the two sets of stator windings meets ; A permanent magnet is embedded in the rotor, and the thickness of the permanent magnet is the same as that of the rotor; the permanent magnet on the rotor is single polarity; the speed of the magnetic field generated by the inner and outer stator windings meets the rotor speed. , that is, the frequencies of the inner and outer stator windings meet .

[0022] The power winding output terminal is directly connected to the power frequency grid, and the control winding output terminal is connected to the power frequency grid through the inverter; the permanent magnet is embedded in the rotor and shows the same polarity to the outside (both are N or S ), the mechanical angle of the ferromagnetic pole with the smallest circumference between two adjacent permanent magnets is , the thickness of the permanent magnet is the same as the thickness of the rotor, and the number of permanent magnets is the same as the number of control winding poles, both The rotor of the present invention adopts axial laminations and has no brush device on the rotor side, so it has high reliability.

[0023] In this embodiment, the number of pole pairs of an outer stator winding is selected as The brushless doubly-fed motor is selected with the number of inner stator winding pole pairs as In the embodiment, the number of outer stator slots is selected as 36, and its structure is as follows Figure 2 As shown; the number of inner stator slots is selected as 24, and its structure is as follows Figure 3 The rotor is located between the inner and outer stators. The permanent magnets are radially magnetized. The number of permanent magnets is the same as the number of control winding poles, both 2. The thickness of the permanent magnets is the same as the thickness of the rotor. The rotor structure is as follows: Figure 4 shown.

[0024] Since the pole pairs of the two sets of windings on the inner and outer stators are different, direct coupling cannot be achieved. Instead, the magnetic field with the required pole pairs of the power winding must be generated through the combined action of the control winding and the rotor. When the control winding generates a magnetic field with the same speed, the synthetic magnetic field can be kept constant, thus realizing the stable electromechanical energy conversion. Therefore, the frequency of the control winding excitation current satisfies , the power winding output frequency meets ,Right now . Figure 5 The magnetic field line distribution diagram of the motor under the combined action of the internal stator control winding and the rotor is given. Figure 5 It can be seen that the magnetic lines of force are distributed in 6 poles, which is the same as the number of pole pairs of the outer stator power winding. Figure 6 The waveform of the power winding output voltage and its Fourier analysis are shown in Figure 2. Figure 6 As can be seen from (a), the three-phase output voltage waveform has good positive linearity. Figure 6 (b) gives the Fourier analysis of a phase voltage at this time. Figure 6 (b) It can be seen that the fundamental amplitude of the voltage is 328V and the frequency is 50Hz, which meets the requirements of the power generation voltage, and the power generation performance of the motor is relatively good.

[0025] It should be understood that various components of the present invention may be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods may be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof may be used: a discrete logic circuit having logic gate circuits for implementing logic functions on data signals, an application-specific integrated circuit having suitable combinational logic gate circuits, a programmable gate array (PGA), a field-programmable gate array (FPGA), etc.

[0026] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0027] Furthermore, 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 the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0028] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A double-stator hybrid excitation alternating-pole brushless doubly-fed motor, comprising an outer stator, an inner stator and a rotor, wherein the outer stator is provided with a pole pair number of The power winding is arranged on the inner stator with a pole pair number of The control winding of the outer stator is provided with a set of power windings; the inner stator is provided with a set of control windings, characterized in that: The number of pole pairs of the power winding and the control winding satisfies , A permanent magnet is embedded in the rotor, and the thickness of the permanent magnet is the same as that of the rotor; the permanent magnet on the rotor is single polarity, and the speed of the magnetic field generated by the inner and outer stator windings meets the rotor speed. , that is, the frequencies of the inner and outer stator windings meet ; The direction of the magnetic field formed by the control winding is directly opposite to the axis of the ferromagnetic pole, and the air gap magnetic field is adjusted by changing the magnitude of the control winding excitation; The permanent magnets are installed in the rotor at intervals by embedding and show the same polarity to the outside. The mechanical angle of the ferromagnetic poles with a small circumference between two adjacent permanent magnets is .

2. The dual-stator hybrid excitation alternating-pole brushless doubly-fed motor according to claim 1, characterized in that: The number of slots of the outer stator slots and the inner stator slots is equal or unequal.

3. The dual-stator hybrid excitation alternating-pole brushless doubly-fed motor according to claim 1, characterized in that: The number of the permanent magnets is the same as the number of control winding poles, both of which are .

4. The dual-stator hybrid excitation alternating-pole brushless doubly-fed motor according to claim 1, characterized in that: The rotor adopts axial lamination.

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