A three-phase multi-pole magnetoresistive resolver that can replace the Hall sensor

Abstract

The present invention discloses a three-phase multi-pole reluctance resolver that can replace a Hall sensor, comprising a stator and a rotor, wherein the inner ring of the stator has a plurality of stator teeth, the outer ring of the rotor has a plurality of salient poles, the number of the stator teeth is 3n times the number of salient poles, and n is a positive integer; four sets of coils are wound around the plurality of stator teeth, which are respectively an excitation coil, a first signal coil, a second signal coil, and a third signal coil, so that the three-phase multi-pole reluctance resolver outputs a three-phase alternating voltage signal. The three-phase multi-pole reluctance resolver designed by the present invention can directly replace the Hall sensor, realize the commutation of a brushless DC motor, and adapt to the application characteristics of the brushless DC motor application with low angle subdivision requirements and low cost.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to a three-phase multi-pole magnetoresistive resolver capable of replacing a Hall sensor. Background Art

[0002] Nowadays, Hall sensors are widely used in civil electromechanical systems. Generally, one motor needs three Hall sensors to realize the normal operation of the brushless DC motor. However, the Hall sensor is a chip device with poor environmental adaptability, low temperature resistance, and is prone to current breakdown, insulation zeroing and other faults. The reluctance resolver is simply composed of magnetic silicon steel sheets and enameled wires, as well as auxiliary components such as skeletons and connectors. The structure is very simple and is particularly suitable for accurate measurement of angles and angular velocities in extremely harsh environments. The stator of a conventional two-phase reluctance resolver is embedded with three sets of coils, namely: excitation input coil, sine output coil and cosine output coil. The two-phase sine and cosine windings are spaced 90° apart, and the real-time angle can be calculated by inverse tangent demodulation. However, the brushless DC motor does not need to detect the motor rotor position in real time. It only needs to obtain 6 rotor position signals with an interval of 60° within one electrical cycle to achieve phase change. Through the demodulation of the two-phase conventional resolver signal, the demodulation algorithm is complex and the decoding chip cost is high, which is not suitable for the application characteristics of low angle segmentation requirements and low cost of brushless DC motor applications. Summary of the invention

[0003] In view of this, the present invention proposes a three-phase multi-pole magnetoresistive resolver that can replace the Hall sensor. The circuit based on the Hall sensor can realize the commutation of the brushless DC motor and can adapt to the application characteristics of the brushless DC motor that has low requirements for angle subdivision and low cost.

[0004] In order to solve the above problems, the present invention proposes the following technical solutions:

[0005] A three-phase multi-pole reluctance resolver capable of replacing a Hall sensor comprises a stator and a rotor, wherein the inner ring of the stator has a plurality of stator teeth, the outer ring of the rotor has a plurality of salient poles, the number of the stator teeth is 3n times the number of salient poles, and n is a positive integer; four sets of coils are wound around the plurality of stator teeth, namely, an excitation coil, a first signal coil, a second signal coil, and a third signal coil, so that the three-phase multi-pole reluctance resolver outputs a three-phase alternating voltage signal.

[0006] Furthermore, the number of the stator teeth is 6n times the number of the salient poles.

[0007] Furthermore, each stator tooth is wound with the excitation coil and is also wound with one of the first signal coil, the second signal coil and the third signal coil.

[0008] Furthermore, the excitation coils wound on two adjacent stator teeth are in opposite phases, and the first signal coil, the second signal coil, and the third signal coil wound on different stator teeth are in the same phase.

[0009] Furthermore, the first signal coil, the second signal coil and the third signal coil are sequentially wound on the plurality of stator teeth in a periodic manner.

[0010] Furthermore, the number of turns of the excitation coil wound on each stator tooth is the same; the number of turns of the first signal coil, the second signal coil and the third signal coil wound on different stator teeth are the same.

[0011] Furthermore, the salient poles of the rotor are square salient poles, trapezoidal salient poles or circular arc salient poles.

[0012] Furthermore, the phase difference between any two phases of the three-phase alternating voltage signal is 120 electrical degrees.

[0013] Furthermore, the three-phase alternating voltage signal is connected to a voltage ratio circuit for analog-to-digital conversion to form a 0 / 1 alternating signal.

[0014] Furthermore, for each phase of the three-phase alternating voltage signal, if the voltage is higher than 0, 1 is output, and if the voltage is lower than 0, 0 is output.

[0015] The beneficial effects of the technical solution of the present invention are embodied in that the number of stator teeth of the three-phase multi-polar reluctance rotary transformer designed by the present invention is 3n times the number of salient poles, and four sets of coils (excitation coils and three sets of coils corresponding to three-phase signals) are wound on these stator teeth, so that the three-phase multi-polar reluctance rotary transformer of the present invention outputs an alternating voltage signal with a three-phase phase difference of 120°, and there is a zero crossing point for the three signals every 60° in the entire cycle. By performing voltage zero crossing detection on the three-phase signal, 6 equally spaced commutation points can be obtained in one cycle, and 1 is output when the amplitude is greater than 0, and 0 is output when the amplitude is less than 0, so as to achieve the same effect as the phase change of the Hall sensor. Therefore, the commutation of the brushless DC motor can be directly replaced by the Hall sensor. At the same time, since only the zero crossing point of the three-phase signal needs to be detected, and the angle of the three phases does not need to be detected in real time, the demodulation algorithm and circuit are simple and the cost is low. Compared with the two-phase reluctance rotary transformer, it is more suitable for the characteristics of the brushless DC motor with low angle segmentation requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of a three-phase multi-pole magnetoresistive resolver provided by an embodiment of the present invention that can replace a Hall sensor.

[0017] Figure 2 Schematic diagram of a three-phase alternating voltage signal output by a three-phase multi-polar magnetoresistive resolver according to an embodiment of the present invention.

[0018] Explanation of the reference numerals: 10 - stator, 11 - stator tooth; 20 - rotor, 21 - first salient pole, 22 - second salient pole. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods and examples. It should be noted that the purpose of providing the examples is only to illustrate and is not intended to limit the present invention.

[0020] Please refer to Figure 1 The three-phase multi-pole reluctance resolver that can replace the Hall sensor proposed in the embodiment of the present invention includes a stator 10 and a rotor 20, wherein the stator 10 and the rotor 20 are both laminated annular cores made of soft magnetic materials. The inner ring of the stator 10 is processed with a tooth slot structure, and the tooth slot structure includes a plurality of stator teeth 11 and slots sandwiched between the stator teeth 11, that is, the tooth slot structure includes the same number of stator teeth and slots, and the stator teeth and slots are arranged crosswise with each other, there is a slot between two adjacent stator teeth, and there is a stator tooth between two adjacent slots. The outer ring of the rotor 20 is formed with a plurality of salient poles. Figure 1 In the embodiment shown, the number of stator teeth 11 of the stator 10 is 12, and the number of salient poles of the rotor 20 is two, namely, the first salient pole 21 and the second salient pole 22. However, this is only exemplary. In the embodiment of the present invention, the number of stator teeth is 3n times the number of salient poles, that is, (3×n) times, where n is a positive integer. The three-phase multi-pole reluctance resolver in the embodiment of the present invention has four sets of coils wound on several stator teeth, namely, the excitation coil (J+, J-), the signal A coil (A+, A-), the signal B coil (B+, B-) and the signal C coil (C+, C-). The winding of the four sets of coils enables the three-phase multi-pole reluctance resolver to output a three-phase alternating voltage signal. The phase difference between any two phases of the output three-phase alternating voltage signal is 120 degrees electrical angle. The three-phase alternating voltage signal is connected to the voltage ratio circuit for analog-to-digital conversion to form a 0 / 1 alternating signal. If the voltage is higher than 0, 1 is output, and if the voltage is lower than 0, 0 is output.

[0021] The three-phase multi-pole reluctance rotary transformer of the embodiment of the present invention replaces the Hall sensor to realize the commutation of the brushless DC motor. Compared with the two-phase reluctance rotary transformer, it has the advantages of simple demodulation algorithm, circuit and low cost, and is more suitable for the application of brushless DC motors than the two-phase reluctance rotary transformer. The angle segmentation requirements are not high. Specifically, the two-phase rotary transformer sensor outputs two sine and cosine signals, and the sine and cosine signals differ by 90°. If the two-phase rotary transformer sensor is used to detect the commutation position of the brushless DC motor, it is necessary to perform real-time detection of the sine and cosine signals and demodulate each angle point of the whole cycle, and control the commutation of the motor at 6 equally spaced position points in one cycle, for example: the two-phase rotary transformer performs real-time angle demodulation calculation, and controls the motor current commutation at 0°, 60°, 120°, 180°, 240°, and 300°. This makes the real-time demodulation operation of the two-phase rotary transformer complex, the amount of operation is large, and the cost of the drive circuit is high. The three-phase multi-polar reluctance resolver of the embodiment of the present invention can output three-phase alternating voltage signals A, B, and C with a phase difference of 120°. Figure 2 As shown, every 60° in the whole cycle, there is a zero crossing point in the three-phase signal. By performing voltage zero crossing detection on the three-phase signal, 6 equally spaced commutation points can be obtained in one cycle. When the amplitude is greater than 0, 1 is output, and when the amplitude is less than 0, 0 is output, which can achieve the same effect as the Hall sensor commutation; and only the zero crossing point of the three-phase signal needs to be detected, and the angle of the three phases does not need to be detected in real time, so the demodulation algorithm and demodulation circuit are simple and low in cost. Therefore, the three-phase multi-pole reluctance resolver of the present invention is more suitable for the commutation of brushless DC motors that do not require high angle subdivision than the two-phase resolver.

[0022] In a preferred embodiment, the number of stator teeth is 6n times the number of salient poles, that is, (6×n), where n is a positive integer. Figure 1 In the illustrated embodiment, the number of salient poles is 2, the number of stator teeth is 12, and the number of stator teeth is 6 times the number of salient poles. For another example, when the number of salient poles is 3, the number of stator teeth is 18. In these preferred embodiments, a group of excitation coils and a group of signal A coils (or signal B coils, or signal C coils) are wound on each stator tooth at the same time, that is, when the number of stator teeth is 6n times the number of salient poles, any two of the signal A coils, signal B coils, and signal C coils are not wound on the same stator tooth; the excitation coils wound on two adjacent stator teeth are in anti-phase, the signal A coils, signal B coils, and signal C coils wound on different stator teeth are in phase, and the signal A coils, signal B coils, and signal C coils are wound in sequence on several stator teeth in a periodic manner.

[0023] by Figure 1For example, a group of excitation coils (J+, J-) and a group of signal A coils (A+, A-) are wound on the stator teeth at 12 o'clock, a group of excitation coils (J-, J+) and a group of signal B coils (B+, B-) are wound on the stator teeth at 1 o'clock, and a group of excitation coils (J+, J-) and a group of signal C coils (C+, C-) are wound on the stator teeth at 2 o'clock. At this point, the signal A coil, signal B coil, and signal C coil complete a cycle of winding. Next, a group of excitation coils and a group of signal A coils are wound at 3 o'clock, a group of excitation coils and a group of signal B coils are wound at 4 o'clock, and a group of excitation coils and a group of signal C coils are wound at 5 o'clock; and so on, winding is carried out in a cycle. The excitation coils wound on two adjacent stator teeth are in anti-phase, such as Figure 1 , on several stator teeth, they are wound in the manner of J+, J-, J-, J+, J+, J-, J-, J+... The signal A coil, signal B coil and signal C coil are wound in phase on different stator teeth in the manner of A+, A-, B+, B-, C+, C-, A+, A-, B+, B-, C+, C-...

[0024] In a more preferred embodiment, the number of turns of the excitation coil wound on each stator tooth is the same; the number of turns of the signal A coil, the signal B coil and the signal C coil wound on different stator teeth are the same.

[0025] In addition, it should be noted that the salient poles of the rotor 20 may be square salient poles, trapezoidal salient poles or circular arc salient poles. Figure 1 The figure shows a type of arc-shaped salient pole.

[0026] A specific embodiment of the three-phase multi-pole magnetoresistive resolver of the present invention that can replace the Hall sensor is provided below.

[0027] The three-phase multi-pole reluctance resolver of this embodiment takes the scheme of the three-phase reluctance resolver with an outer diameter of 52 mm as an example. Four sets of coils are wound on the stator teeth, including an excitation input coil, a signal A coil, a signal B coil and a signal C coil.

[0028] The number of stator teeth of the reluctance resolver is: 12 teeth;

[0029] The number of salient poles of the rotor of the reluctance resolver is 2, that is, 2 pairs of poles; the shape of the salient poles is arc-shaped.

[0030] Each set of excitation coils wound on the 12 stator teeth has 35 turns, and adjacent teeth are wound in opposite directions. Taking 12 o'clock as the first tooth, the odd-numbered teeth 1, 3, 5, 7, 9, and 11 are wound in the forward direction, and the even-numbered teeth 2, 4, 6, 8, 10, and 12 are wound in the reverse direction.

[0031] The number of turns of a set of signal A coils is 93, which are wound at 1, 4, 7, and 10 teeth, and are all wound in the forward direction;

[0032] The number of turns of a set of signal B coils is 93, which are wound on the 2nd, 5th, 8th and 11th teeth, and are all wound in the forward direction;

[0033] A set of signal C coils has 93 turns, which are wound at 3, 6, 9, and 12 teeth, and are all wound in the forward direction.

[0034] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art of the present invention, several equivalent substitutions or obvious variations can be made without departing from the concept of the present invention, and the performance or use is the same, which should be regarded as belonging to the protection scope of the present invention.

Claims

1. A three-phase multi-pole reluctance resolver that can replace a Hall sensor, comprising a stator and a rotor, characterized in that: The three-phase multi-pole reluctance resolver can realize the commutation of the brushless DC motor by the following configuration: The inner ring of the stator has a plurality of stator teeth, and the outer ring of the rotor has a plurality of salient poles, and the number of the stator teeth is 6 times the number of salient poles; four sets of coils are wound on the plurality of stator teeth, namely, an excitation coil, a first signal coil, a second signal coil and a third signal coil, so that the three-phase multi-polar reluctance rotary transformer outputs a three-phase alternating voltage signal; wherein, the excitation coil is wound on each stator tooth, and at the same time, one of the first signal coil, the second signal coil and the third signal coil is wound on each stator tooth; the excitation coils wound on two adjacent stator teeth are in anti-phase, and the first signal coil, the second signal coil and the third signal coil wound on different stator teeth are in phase; the first signal coil, the second signal coil and the third signal coil are wound on the plurality of stator teeth in sequence according to a period; the number of turns of the excitation coil wound on each stator tooth is the same; the number of turns of the first signal coil, the second signal coil and the third signal coil wound on different stator teeth is the same.

2. The three-phase multi-polar reluctance resolver according to claim 1, characterized in that: The salient poles of the rotor are square salient poles, trapezoidal salient poles or circular arc salient poles.

3. The three-phase multi-polar reluctance resolver according to claim 1, characterized in that: The phase difference between any two phases of the three-phase alternating voltage signal is 120 electrical degrees.

4. The three-phase multi-polar reluctance resolver according to claim 3, characterized in that: The three-phase alternating voltage signal is connected to a voltage ratio circuit for analog-to-digital conversion to form a 0 / 1 alternating signal.

5. The three-phase multi-polar reluctance resolver according to claim 4, characterized in that: For each phase of the three-phase alternating voltage signal, if the voltage is higher than 0, 1 is output; if the voltage is lower than 0, 0 is output.

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