Frequency division rotary transformer decoding system

Abstract

The utility model relates to the technical field of wind turbine generator variable-pitch motor control, and discloses a frequency-division rotary transformer decoding system, a rotary transformer is installed at the end part of a casing of a wind turbine generator variable-pitch motor, the rotary transformer is formed by coaxially installing three groups of coil groups around a rotor, and the coil numbers of the three groups of coil groups are different; according to the rotor, rotor magnets are fixed to the positions, corresponding to the coil sets, of a rotor shaft, the number of the rotor magnets is consistent with the number of coils in the coil sets, the output of the rotary transformer is connected with an FFT filter circuit, three paths of the FFT filter circuit are connected with three paths of rotary transformer decoders in a frequency division mode, and the three paths of rotary transformer decoders are in communication connection with an interface circuit used for being connected with external control equipment. According to the utility model, the reliability of the rotary transformer decoding in the long-term use and operation process can be greatly improved, the anti-interference capability is strong, the fault rate is effectively reduced, and the operation error-tolerant rate in the maintenance process is obviously improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of generator control, especially the technical field of rotor position or rotor speed sensor use. BACKGROUND

[0002] At present, the rotor position is determined on the wind driven generator generally adopts the encoder or hall sensor, but the precision of hall sensor is lower, the stability and durability of encoder are poor, along with the structural improvement of wind driven power generation, at present, in some more advanced wind driven power generation applications, hall sensor and encoder have been difficult to meet the long-term stable operation requirement.

[0003] The determination of rotor position by resolver decoding can obtain higher precision and durability, but the general resolver decoding system needs to ensure the accurate unity of the coil on the resolver and the position of the rotor magnet, and needs to ensure the relative stability of the operating environment, but such conditions do not have in many wind driven generator variable pitch systems, which are long-term in high-speed rotation and vibration environment, which leads to that the general resolver decoding system installed in the wind turbine generator has poor structure, inconvenient maintenance and high failure rate, and low operation fault tolerance rate in the maintenance process. UTILITY MODEL CONTENTS

[0004] The utility model aims at providing a kind of frequency division resolver decoding system, can greatly improve the reliability of resolver decoding in long-term use operation process, strong anti-interference ability, effectively reduce failure rate, significantly improve the operation fault tolerance rate in maintenance process.

[0005] To solve the above technical problems, the utility model provides a kind of frequency division resolver decoding system, the end of the shell of generator is installed resolver, and the resolver is composed of three groups of coaxial coil groups around the rotor installation, the coil quantity of three groups of coil groups is different, the rotor is fixed with the rotor magnet of the same number of coil quantity in the coil group in the position corresponding to each coil group on the rotor shaft, the resolver output is connected to FFT filter circuit, FFT filter circuit is connected to three-way resolver decoder by three-way frequency division, and three-way resolver decoder is connected to interface circuit for connecting external control equipment;FFT filter circuit, resolver decoder and interface circuit are located on the same PCB, and the PCB is installed in interface circuit box and fixed to the shell.

[0006] The FFT filter circuit is connected by three-way frequency division, and is specifically divided into high-frequency connection, medium-frequency connection and low-frequency connection.

[0007] The high-frequency connection is low-frequency and medium-frequency filtering, the medium-frequency connection is low-frequency and high-frequency filtering, and the low-frequency connection is high-frequency and medium-frequency filtering.

[0008] The position between the three groups of coil groups has a partition plate for isolating magnetic field.

[0009] The three groups of coil groups are middle frequency coil group, high frequency coil group and low frequency coil group, the number of coils in the middle frequency coil group is less than two-thirds of the number of coils in the high frequency coil group, and is more than 1.5 times of the number of coils in the low frequency coil group; there is a middle-high partition between the middle frequency coil group and the high frequency coil group, and there is a high-low partition between the high frequency coil group and the low frequency coil group.

[0010] The number of coils in the high frequency coil group is a prime number, and the number of coils in the middle frequency coil group is an even number.

[0011] The FFT filter circuit is realized by FPGA.

[0012] The FFT filter circuit is one-way signal input, and three-way independent FFT cores are tapped, and each FFT core is connected with one-way output.

[0013] The coils in the coil group are uniformly distributed along the circumference.

[0014] Compared with the prior art, the present application can significantly improve the accuracy of the resolver decoding control, effectively improve the service life of the resolver control system, reduce the maintenance cost, improve the reliability and stability of the resolver control motor system, can significantly help to accurately decode the rotor position information, effectively avoid decoding errors or position detection deviation, more effectively ensure the realization of high-precision position detection, provide reliable position signal for accurate control of the generator, facilitate self-calibration, greatly improve the reliability of resolver decoding in long-term use, have strong anti-interference ability, and the whole system is very compact and neat, and can better meet the space layout requirements.

[0015] The above description is only a summary of the technical scheme of the present application, in order to more clearly understand the technical means of the present application, the specific embodiments of the present application can be implemented according to the content of the specification, and in order to make the above and other purposes, characteristics and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described below. BRIEF DESCRIPTION OF DRAWINGS

[0016] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings, which do not constitute a limitation on the embodiments, and the elements with the same reference numerals in the drawings represent similar elements, unless otherwise specified, and the drawings do not constitute a proportional limitation.

[0017] Figure 1 is a structural schematic diagram of an embodiment of the present application;

[0018] Figure 2 is Figure 1 is a schematic diagram of the internal structure of a partial cut of the casing;

[0019] Figure 3 is Figure 1 Explosive diagram after removing the shell;

[0020] Figure 4 is Figure 1 Installation structure diagram of the intermediate frequency coil group;

[0021] Figure 5 is Figure 1 Installation structure diagram of the high frequency coil group;

[0022] Figure 6 is Figure 1 Installation structure diagram of the low frequency coil group;

[0023] Figure 7 is the connection diagram of an embodiment of the utility model.

[0024] In the figure: 1 - shell, 2 - rotor, 201 - rotor shaft, 202 - rotor magnet, 3 - interface circuit box, 4 - intermediate frequency coil group, 401 - first intermediate frequency coil, 402 - second intermediate frequency coil, 403 - third intermediate frequency coil, 5 - high intermediate partition, 6 - high frequency coil group, 601 - first high frequency coil, 602 - second high frequency coil, 603 - third high frequency coil, 7 - high-low partition, 8 - low frequency coil group, 801 - first low frequency coil, 802 - second low frequency coil. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the utility model more clear, the following will combine the attached drawing to carry out the detailed elaboration to each embodiment of the utility model. However, the ordinary skilled in the art can understand that in each embodiment of the utility model, in order to make the reader better understand the present application and proposed many technical details. However, even without these technical details and based on the various changes and modifications of each embodiment, the technical scheme claimed by the present application can be realized. The division of the following each embodiment is for the convenience of description, and should not constitute any limitation to the specific implementation of the utility model, and each embodiment can be combined with each other under the premise of not contradicting.

[0026] The first embodiment of the utility model relates to a frequency division resolver decoding system, such as Figures 1 to 7As shown, the end of the generator shell 1 is mounted with a rotary transformer, which is composed of three sets of coil groups coaxially surrounding the rotor 2, the number of coils in the three sets of coil groups is different, the rotor 2 is fixed with rotor magnets 202 corresponding to the position of each coil group on the rotor shaft 201, the number of rotor magnets 202 is consistent with the number of coils in the coil group, the rotary transformer output is connected to the FFT filter circuit, the FFT filter circuit is connected to the three-way rotary transformer decoder through three-way frequency division, and the three-way rotary transformer decoder is connected to the interface circuit for connecting external control equipment; The FFT filter circuit, the rotary transformer decoder and the interface circuit are located on the same PCB, and the PCB is installed in the interface circuit box 3 and fixed to the shell 1.

[0027] Therefore, based on multiple coil groups, more abundant signal changes can be provided, and the output signal is a level signal combined by multiple frequency waveforms. After being filtered by the FFT filter circuit, the signal can be decomposed into multiple level signals, and the signals of the corresponding coil groups can be obtained by rotary decoding. By comparing multiple signals, the rotating position of the rotor can be easily determined. The waveform merging and filtering decomposition decoding on the same PCB can effectively solve the interference problem of multiple level signals in the transmission line. Since the waveform decoding method and the waveform comparison method are used to determine the rotating position of the rotor, the accuracy is guaranteed, and the fault tolerance during installation and maintenance is greatly improved.

[0028] Especially for wind power variable pitch applications, local structure misplacement is a very common situation during long-term use, and such structure misplacement can cause persistent changes in magneto-electric signals, which deviate from the factory settings. The specific manifestation is the periodic fixed clutter in the waveform of the level signal. Based on the above-mentioned substantial improvement of fault tolerance, the problem of fixed clutter caused by structure misplacement during long-term use can be well solved, and the multiple waveforms can be compared with each other to form a reference for correcting the fixed clutter.

[0029] The second embodiment of the utility model is basically the same as the first embodiment, mainly in that the FFT filter circuit is connected through three-way frequency division, and is specifically connected through high-frequency connection, medium-frequency connection and low-frequency connection.

[0030] Further, the high-frequency connection is for low-frequency and medium-frequency filtering, the medium-frequency connection is for low-frequency and high-frequency filtering, and the low-frequency connection is for high-frequency and medium-frequency filtering.

[0031] As can be easily understood, the FFT filter circuit is generally connected and controlled by an external control system. The external control system divides the high, medium and low frequency demarcation values according to the control needs, and independently sets the signal lines connected to the FFT filter circuit in the interface circuit, so that the external control system controls through independent pins.

[0032] The third embodiment of the present invention is substantially the same as the first embodiment, except that partitions for isolating magnetic fields are provided between the three coil groups.

[0033] Furthermore, the three coil groups are a medium-frequency coil group 4, a high-frequency coil group 6, and a low-frequency coil group 8. The number of coils in the medium-frequency coil group 4 is less than two-thirds of the number of coils in the high-frequency coil group 6, and is more than 1.5 times the number of coils in the low-frequency coil group 8. There is a medium-high partition 5 between the medium-frequency coil group 4 and the high-frequency coil group 6, and a high-low partition 7 between the high-frequency coil group 6 and the low-frequency coil group 8.

[0034] Furthermore, the number of coils in the high-frequency coil group 6 is a prime number, and the number of coils in the medium-frequency coil group 4 is an even number.

[0035] Therefore, the high-frequency coil group 6 is between the medium-frequency coil group 4 and the low-frequency coil group 8, and the number of coils is a prime number, which can effectively avoid the problem of co-frequency interference, and the number of coils in the medium-frequency coil group 4 can serve as an excellent calibration basis.

[0036] Furthermore, the FFT filtering circuit is implemented using FPGA.

[0037] Furthermore, the FFT filter circuit has one signal input, which is connected to three independent FFT cores, and each FFT core is connected to one output.

[0038] Furthermore, the coils in the coil group are evenly distributed along the circumference.

[0039] In a typical embodiment, the intermediate frequency coil assembly 4 includes 12 coils, the high frequency coil assembly 6 includes 19 coils, and the low frequency coil assembly 8 includes 3 coils. On the rotor shaft 201, there are 12 rotor magnets 202 at positions corresponding to the intermediate frequency coil assembly 4, 19 rotor magnets 202 at positions corresponding to the high frequency coil assembly 6, and 3 rotor magnets 202 at positions corresponding to the low frequency coil assembly 8. Based on this quantitative correspondence, when the first low frequency coil 801 in the low frequency coil assembly 8 faces the rotor magnet 202, the second low frequency coil 802 in the low frequency coil assembly 8 also faces the rotor magnet 202, and the two can form mutual induction. Similarly, the first intermediate frequency coil 401, the second intermediate frequency coil 402, and the third intermediate frequency coil 403 in the intermediate frequency coil assembly 4 can also form mutual induction, and the first high frequency coil 601, the second high frequency coil 602, and the third high frequency coil 603 in the high frequency coil assembly 6 can also form mutual induction. This ensures periodicity consistency while also enhancing the signal. When the intermediate frequency coil group 4 passes through 3 signal cycles, i.e., the first intermediate frequency coil 401, the second intermediate frequency coil 402 and the third intermediate frequency coil 403 rotate past 3 rotor magnets 202 at their corresponding positions on the rotor shaft 201, the high frequency coil group 6 passes through 4.75 signal cycles, i.e., the first high frequency coil 601, the second high frequency coil 602 and the third high frequency coil 603 rotate past 4.75 rotor magnets 202 at their corresponding positions on the rotor shaft 201, and the low frequency coil group 8 passes through 0.75 signal cycles, i.e., the first low frequency coil 801 and the second low frequency coil 802 rotate past 4.75 rotor magnets 202 at their corresponding positions on the rotor shaft 201. The corresponding position on 01 rotates through 0.75 rotor magnets 202, resulting in a frequency ratio of the level signals generated by the intermediate frequency coil group 4, the high frequency coil group 6, and the low frequency coil group 8 being 12:19:3 during the rotation of the rotor shaft 201. The high frequency coil group 6 isolates the intermediate frequency coil group 4 and the low frequency coil group 8, which can effectively avoid interference. As for FFT filtering, since the amplitude of the level signal generated by the low frequency coil group 8 is different depending on whether the waveform signal is superimposed on it, the multiple relationship between the number of coils of the intermediate frequency coil group 4 and the low frequency coil group 8 will not affect the FFT filtering.

[0040] Based on the above implementation methods, it can be seen that the utility model can significantly facilitate accurate decoding of rotor position information, effectively avoid decoding errors or position detection deviations, more effectively ensure high-precision rotor position detection, provide reliable position signals for precise control of the generator, facilitate self-calibration, and greatly improve the reliability of resolver decoding during long-term operation. It has strong anti-interference ability, and the entire system is extremely compact and neat, which can better meet the spatial layout requirements.

[0041] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present invention, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A frequency division resolver decoding system, characterized in that: A rotary transformer is installed at the end of the housing (1). The rotary transformer is composed of three coil groups coaxially mounted around a rotor (2). The three coil groups have different numbers of coils. The rotor (2) is a rotor shaft (201) on which a number of rotor magnets (202) corresponding to the number of coils in each coil group is fixed. The output of the rotary transformer is connected to an FFT filter circuit. The three-way frequency division of the FFT filter circuit is connected to a three-way rotary decoder. The three-way rotary decoder is communicatively connected to an interface circuit for connecting to an external control device. The FFT filter circuit, the resolver decoder and the interface circuit are all located on the same PCB, which is installed in the interface circuit box (3) and fixed to the housing (1).

2. The frequency division resolver decoding system according to claim 1, wherein: The FFT filter circuit has three-way frequency division connection, specifically divided into high frequency connection, intermediate frequency connection and low frequency connection.

3. The frequency division resolver decoding system according to claim 2, wherein: The high frequency connection is for filtering low frequency and medium frequency, the medium frequency connection is for filtering low frequency and high frequency, and the low frequency connection is for filtering high frequency and medium frequency.

4. The frequency division resolver decoding system according to claim 1, wherein: Partitions for isolating magnetic fields are arranged between the three coil groups.

5. The frequency rotation decoding system according to any one of claims 1 or 4, characterized in that: The three coil groups are respectively a medium-frequency coil group (4), a high-frequency coil group (6), and a low-frequency coil group (8); the number of coils in the medium-frequency coil group (4) is less than two-thirds of the number of coils in the high-frequency coil group (6), and is more than 1.5 times the number of coils in the low-frequency coil group (8); a medium-high partition (5) is provided between the medium-frequency coil group (4) and the high-frequency coil group (6), and a high-low partition (7) is provided between the high-frequency coil group (6) and the low-frequency coil group (8).

6. The frequency division resolver decoding system according to claim 5, characterized in that: The number of coils in the high-frequency coil group (6) is a prime number, and the number of coils in the medium-frequency coil group (4) is an even number.

7. The frequency division resolver decoding system according to claim 1, wherein: The FFT filtering circuit is implemented using FPGA.

8. The frequency division resolver decoding system according to claim 1, wherein: The FFT filter circuit has one signal input, which is connected to three independent FFT cores, and each FFT core is connected to one output.

9. The frequency division resolver decoding system according to claim 1, wherein: The coils in the coil group are evenly distributed along the circumference.

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