阅读说明：本技术 一种编码器零位信号丢失补偿装置及方法 (Encoder zero signal loss compensation device and method ) 是由 刘嘉明 余诗宝 吴立建 王海洋 崔杰 付厚 于 2020-04-28 设计创作，主要内容包括：本发明公开了一种编码器零位信号丢失补偿装置及方法,将补偿装置分别与所述编码器和变流器连接；当发电机主轴旋转一圈,则带动编码器旋转一圈,产生光栅刻度数值个A脉冲信号和B脉冲信号；补偿装置中的处理器判断此时是否出现一次Z脉冲信号,若否,则处理器进行Z脉冲信号补偿,在在零位信号计数周之后自动生成一个Z脉冲信号并给到变流器。本发明的用于风力发电机和变流器的编码器Z脉冲丢失补偿方法,可以用较少的成本,降低Z脉冲丢失导致的停机故障概率。(The invention discloses a device and a method for compensating zero position signal loss of an encoder, wherein the compensating device is respectively connected with the encoder and a converter; when the main shaft of the generator rotates for a circle, the encoder is driven to rotate for a circle, and a grating scale numerical value A pulse signal and a grating scale numerical value B pulse signal are generated; and a processor in the compensation device judges whether a Z pulse signal appears once, if not, the processor performs Z pulse signal compensation, and automatically generates a Z pulse signal after the zero position signal is counted for several weeks and supplies the Z pulse signal to the converter. The encoder Z pulse loss compensation method for the wind driven generator and the converter can reduce the shutdown fault probability caused by Z pulse loss with less cost.)

1. The encoder zero position signal loss compensation device for the wind driven generator is characterized in that the encoder is an incremental encoder, a main body of the incremental encoder is installed on a generator main shaft of the wind driven generator, the compensation device is respectively connected with the encoder and a converter of the wind driven generator, and pulse signals sent by the encoder comprise first continuous pulse signals, second continuous pulse signals and zero position signals, wherein the phase difference between the second continuous pulse signals and the first continuous pulse signals is a quarter of a period; the compensation device at least comprises a processor which detects whether a zero signal loss condition occurs or not according to the received pulse signals and generates a zero signal compensation signal when the zero signal is lost, and the zero signal compensation signal is provided for the converter.

2. The encoder zero signal loss compensation apparatus of claim 1, wherein the processor is a programmable logic device CP L D.

3. An encoder null signal loss compensation device as claimed in claim 1, further comprising one or more of:

the signal interface processing circuit receives the pulse signal sent by the encoder, converts a differential signal of the pulse signal into a single-ended signal through an optical coupler, realizes signal isolation and transmits the processed pulse signal to the processor;

and the level matching circuit is connected with the current transformer and is used for carrying out level matching on the output signal of the processor and the input signal of the current transformer.

4. An encoder null signal loss compensation device as claimed in any one of claims 1 to 3,

the first continuous pulse signal, the second continuous pulse signal and the zero position signal are respectively an A pulse signal, a B pulse signal and a Z pulse signal.

5. The encoder null signal loss compensation device of claim 4, wherein the processor comprises:

a pulse counting unit for A, B, Z pulse signal counting by detecting A, B rising edge or falling edge of the pulse signal;

a Z pulse loss judgment unit for detecting whether a Z pulse signal loss condition occurs, which judges whether the Z pulse signal loss condition occurs by detecting a rising edge or a falling edge of the Z pulse signal;

and the compensation unit is used for generating a Z pulse compensation signal.

6. An encoder null signal loss compensation method based on the encoder null signal loss compensation device as claimed in any one of claims 1 to 5, the method comprising the steps of:

connecting the compensating device with the encoder and the converter respectively;

when the main shaft of the generator rotates for a circle, the encoder is driven to rotate for a circle, and a first continuous pulse signal and a second continuous pulse signal with the values of grating scales are generated;

and the processor in the compensation device judges whether a zero position signal appears at the moment or not, if not, the processor performs zero position signal compensation, and automatically generates a zero position compensation signal after a zero position signal counting period and supplies the zero position compensation signal to the converter.

7. The encoder null signal loss compensation method of claim 6, wherein the first continuous pulse signal, the second continuous pulse signal and the null signal are an a pulse signal, a B pulse signal and a Z pulse signal, respectively;

the phase difference between the A pulse signal and the B pulse signal is a quarter of a cycle, and the pulse width Z is half of the pulse width A, B.

8. The encoder null signal loss compensation method of claim 7,

when A, B pulse signals count to the number of grating scale values, according to the phase relation between the current encoder rotating speed and A, B pulse signals, calculating and judging the Z pulse signal counting period of the Z pulse signals, comprising the following steps:

z pulse signal count period T_ZComprises the following steps:wherein N is the rotational speed of the encoder; k represents that the wind driven generator generates K pulse signals in each turn, and K is a frequency multiplication coefficient and an encoder grating scale value;

encoder for encoding a video signalThe rotating speed N is as follows:wherein M is the number of output pulses of the encoder; t is_DIs a set period of time.

9. The encoder zero signal loss compensation method of claim 7, wherein the pulse counting is performed by detecting A, B the rising or falling edge of the pulse signal.

10. The encoder null signal loss compensation method of claim 7, wherein the presence of a Z pulse signal loss condition is determined by detecting a rising or falling edge of the Z pulse signal.

Technical Field

The invention relates to the field of wind driven generator and converter systems, in particular to a device and a method for compensating loss of zero signals (also called Z pulse signals) of encoders for the wind driven generator and converter systems.

Background

The rotating speed detection of the doubly-fed wind generator is important for motor control. At present, the practical encoder transmits A +, A-, B +, B-, Z + and Z-pulse signals through an eight-core cable and supplies power to the encoder. When the encoder rotates, the photoelectric detection device can generate pulse signals A +, A-, B +, B-, Z + and Z-due to the existence of the grating. The A +/A-, B +/B-pulse signal represents the scale of the grating disc, the continuous pulse with the phase difference of 90 degrees (the phase difference of 0.25 cycle) is output, and the forward rotation or the reverse rotation, the speed value and the like can be distinguished by the continuous pulse. The Z pulse signal is zero position signal, and the encoder can send out one signal after rotating one circle, so that the rotation speed and the period can be measured.

Conventionally, as shown in fig. 1, the generator encoder 200 is connected to the tower bottom from the tower top through a cable, and the signal needs to pass through a long wire. The rotating speed of the doubly-fed wind generator is calculated and detected by transmitting A, B, Z pulse signals to a converter rotating speed calculating unit through an incremental encoder, the encoder is installed at the tail end of a tower top generator rotating shaft, A +, A-, B +, B-, Z +, Z-pulse signals are transmitted to a tower bottom converter 300 from the tower top through a cable, and the Z pulse loss condition easily occurs in the actual operation process of a wind field due to the fact that the cable is long in wiring and electromagnetic interference coupling. Taking a 2MW wind turbine generator as an example, the length of a cable of the encoder exceeds 80m from a rotating shaft of a tower top double-fed motor to a tower bottom converter. In fact, the grounding of a shielding wire of the encoder cable is poor, and the routing of the encoder cable is unreasonable (the encoder cable is bound with a main cable or is close to the main cable, so that electromagnetic interference is easily coupled), so that a Z pulse signal is distorted, a Z pulse cannot be detected on the converter side, and the Z pulse loss condition is generated. Moreover, the width of the Z pulse is narrower than that of the A, B pulse signal, and the pulse duty ratio is only half of that of the A, B pulse signal, so that the Z pulse signal is more susceptible.

The wind field site treatment measures mainly include shielding layer single-point grounding and cable arrangement to reduce interference coupling, but the effect is limited. The ABZ signal is transmitted by an optical fiber mode instead of a decoding board of an encoding board, but the ABZ signal transmission method has the problems of high cost and inconvenient installation. A Z pulse interference and loss detection method is provided in the servo field, and when Z pulse loss is detected, the machine is stopped to alarm, and how to compensate Z pulse signals is not involved. In the prior art, the rotation speed is processed and the Z pulse signal is detected through a DSP generally, and the Z pulse signal cannot be compensated. Aiming at the practical application condition in the field of wind power, a method for compensating for Z pulse loss of an encoder of a wind driven generator and a wind power converter needs to be developed.

Disclosure of Invention

The invention aims to provide a Z pulse loss compensation device and a Z pulse loss compensation method for an encoder of a wind driven generator and a converter system, wherein the compensation device detects A, B pulse signals to compensate a Z pulse loss part and eliminate a Z pulse loss fault; even if the Z pulse is lost, the Z pulse signal can be compensated, the implementation is easy, the cost is low, the shutdown fault of the fan caused by the Z pulse loss condition is reduced, and the grid-connected power generation rate is improved.

In order to achieve the purpose, the invention is realized by the following technical scheme:

an encoder zero position signal loss compensation device for a wind driven generator is characterized in that the encoder is an incremental encoder, a main body of the incremental encoder is installed on a generator main shaft of the wind driven generator, the compensation device is respectively connected with the encoder and a converter of the wind driven generator, pulse signals sent by the encoder comprise a first continuous pulse signal, a second continuous pulse signal and a zero position signal, and the phase of the second continuous pulse signal is different from that of the first continuous pulse signal by a quarter period; the compensation device at least comprises a processor which detects whether a zero signal loss condition occurs or not according to the received pulse signals and generates a zero signal compensation signal when the zero signal is lost, and the zero signal compensation signal is provided for the converter.

Preferably, the processor is a programmable logic device CP L D.

Preferably, the compensation means further comprises one or more of: the signal interface processing circuit receives the pulse signal sent by the encoder, converts a differential signal of the pulse signal into a single-ended signal through an optical coupler, realizes signal isolation and transmits the processed pulse signal to the processor; and the level matching circuit is connected with a converter rotating speed processing unit in the converter and is used for carrying out level matching on the output signal of the processor and the input signal of the converter.

Preferably, the first continuous pulse signal, the second continuous pulse signal and the zero position signal are an a pulse signal, a B pulse signal and a Z pulse signal, respectively.

Preferably, the processor comprises: a pulse counting unit for A, B, Z pulse signal counting by detecting A, B rising edge or falling edge of the pulse signal; a Z pulse loss judgment unit for detecting whether a Z pulse signal loss condition occurs, which judges whether the Z pulse signal loss condition occurs by detecting a rising edge or a falling edge of the Z pulse signal; and the compensation unit is used for generating a Z pulse compensation signal.

The invention also provides an encoder zero position signal loss compensation method based on the encoder zero position signal loss compensation device, which comprises the following steps: connecting the compensating device with the encoder and the converter respectively; when the main shaft of the generator rotates for a circle, the encoder is driven to rotate for a circle, and a first continuous pulse signal and a second continuous pulse signal with the values of grating scales are generated; and the processor in the compensation device judges whether a zero position signal appears at the moment or not, if not, the processor performs zero position signal compensation, and automatically generates a zero position compensation signal after a zero position signal counting period and supplies the zero position compensation signal to the converter.

Preferably, the first continuous pulse signal, the second continuous pulse signal and the zero position signal are respectively an a pulse signal, a B pulse signal and a Z pulse signal; the phase difference between the A pulse signal and the B pulse signal is a quarter of a cycle, and the pulse width Z is half of the pulse width A, B.

Preferably, when A, B pulse signals count to the number of grating scale values, calculating and judging the counting period of the Z pulse signals according to the phase relation between the current encoder rotating speed and A, B pulse signals, comprising the following steps:

the counting period of the Z pulse signal is as follows:wherein N is the rotational speed of the encoder; k represents that the wind driven generator generates K pulse signals in each turn, and K is a frequency multiplication coefficient and an encoder grating scale value; the rotating speed N of the encoder is as follows:wherein M is the number of output pulses of the encoder; t is_DIs a set period of time.

Preferably, the pulse counting is performed by detecting A, B a rising or falling edge of the pulse signal

Preferably, whether the Z pulse signal loss condition occurs is determined by detecting a rising edge or a falling edge of the Z pulse signal.

Compared with the prior art, the invention has the beneficial effects that: the encoder Z pulse loss compensation method for the wind driven generator and the converter can reduce the shutdown fault probability caused by Z pulse loss with less cost.

Drawings

FIG. 1 is a schematic diagram of a prior art generator encoder connected from the top of the tower to the bottom of the tower by a cable;

FIG. 2 is a schematic diagram of an encoder Z pulse loss compensation arrangement for a wind turbine and converter system according to the present invention;

FIG. 3 is a schematic diagram of the output signals of the incremental encoder of the wind turbine of the present invention;

fig. 4 is a schematic diagram of the design of the compensating device of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 2-4, the present invention provides an encoder Z pulse loss compensation device 100 for wind power generator and converter system, which comprises a signal interface processing circuit 1, a processor 2 (e.g. CP L D, a programmable logic device that a user can construct logic function according to their own needs) and a level matching circuit 3 connected in sequence, wherein the compensation device 100 is connected with a wind power generator encoder 200 at the tower top and a converter 300 at the tower bottom respectively, the compensation device 100 is arranged at the encoder signal incoming line of the converter at the tower bottom, and the invention can reduce the signal line coupling interference by placing the compensation device close to the converter incoming line.

In this embodiment, the unprocessed A, B, Z pulse signals (e.g., a +, a-, B +, B-, Z +, Z-pulse signals) pass through the signal interface processing circuit 1, and the signal interface processing circuit 1 converts the a + a-/B + B-/Z + Z-differential signals into single-ended signals through the optical coupler device, implements signal isolation, and transmits the processed pulse signals to the CP L D processing chip.

The incremental encoder main body is arranged on a main shaft of a generator of a wind driven generator, the encoder comprises a grating disc and a photoelectric detection device, when the main shaft of the generator rotates, the encoder rotates, and due to the existence of the grating, the photoelectric detection device can generate pulse signals A +, A-, B +, B-, Z + and Z-. The A +/A-, B +/B-pulse signals represent grating disc scales, the phase difference of A, B pulse signals is 90 degrees, and the encoder can be used for distinguishing forward rotation or reverse rotation, speed values and the like; the Z pulse signal is a zero position signal, and when the encoder rotates for one circle, the photoelectric detection device sends out a Z pulse signal which can be used for measuring the rotating speed and the period of the encoder.

CP L D is used as processing core for detecting if Z pulse loss occurs and generating a Z pulse compensation signal when Z pulse is lost, and CP L D is used as processor 2 of the compensation device, and can process input signals in parallel.

The processor 2 (for example, CP L D) comprises a pulse counting unit for A, B pulse counting, a Z pulse loss judging unit for detecting whether a Z pulse loss condition occurs or not, and a compensating unit for supplementing a Z pulse compensating signal, wherein the pulse loss condition can not occur due to the fact that the pulse width is large under the condition that the generator rotates and the compensating device is about to function under the condition that the pulse loss occurs to Z under the condition of large wind speed.

It should be noted that the processor 2 of the present invention is not limited to the above CP L D, and other processors may be adopted, and the present invention adopts CP L D for signal logic processing, mainly considering that the CP L D has a low cost.

The level matching circuit 3 is connected to the converter speed processing unit, and the level matching circuit 3 can perform level conversion, which is used for level matching between the output signal of the processor 2 and the input signal of the converter speed processing unit, i.e. to make the voltages of the front and rear stages close to or the same.

The invention also provides an encoder Z pulse loss compensation method for the wind driven generator and the converter system, which is characterized in that a compensation device 100 (shown in figure 4) is connected to an encoder signal inlet port of the tower bottom converter, and an encoder signal passes through the compensation device and then is transmitted to the converter rotating speed processing unit, so that the rotating speed of the doubly-fed wind driven generator is calculated and detected by transmitting A, B, Z pulses to the converter rotating speed calculating unit. The method for compensating the Z pulse loss of the encoder specifically comprises the following steps:

step S1: the compensation apparatus 100 is designed to include a signal interface processing circuit 1, a processor 2 and an output level matching circuit 3, which are connected in sequence, as shown in fig. 4.

Step S2: the compensation device 100 is installed at the encoder signal inlet wire of the tower bottom converter, and is small in change and convenient to install.

Step S3: when the main shaft of the generator rotates once, the Z pulse signal appears once, and the A, B, Z pulse relationship is as shown in fig. 3, that is, when the encoder rotates once, A, B pulse signals with raster scale values are generated (the raster scale values are fixed, for example, 2048 scales, 2048A, B pulses are generated, and at this time, a Z pulse should appear under the condition that no pulse is lost), and the Z pulse signal is a Z pulse generated after the encoder rotates once; the invention counts through A, B pulses, and when A, B pulse signals reach one circle of pulse numbers (for example 2048 pulses), judges whether Z pulses appear at the moment: if under the condition of the main shaft rotating speed of the generator, the Z pulse counts the time T_ZIf no Z pulse signal is detected in the range, the compensation of the Z pulse signal is performed by CP L D in the compensation device 100, and the Z pulse signal is compensated at T_ZThe counting period (90 ° pulse period in fig. 3, time when the Z pulse signal should appear originally) is followed by automatically generating a Z pulse signal, i.e. a Z pulse compensation signal is automatically generated after a corresponding quarter of a/B pulse width in fig. 3 and is supplied to the converter speed processing unit.

Illustratively, the present invention performs pulse counting by detecting A, B the rising or falling edge of the pulse.

In another example, the invention of compensation through CP L D means that when A, B pulse counts the number of grating scale values, the time when the Z pulse should appear is judged according to the phase relation between the current encoder rotating speed and A, B pulse signal, if the Z pulse does not appear, a Z pulse signal is sent out through CP L D to compensate the lost Z pulse signal, wherein, whether the Z pulse appears or not is judged by detecting the rising edge or the falling edge of the Z pulse.

Specifically, set at a certain time T_DWithin (unit: s), measuring the number M of output pulses of the rotary encoder, wherein each rotation of the wind driven generator is oneThe cycle generates K pulses (K is the multiplication factor x the encoder raster scale value), and the current motor speed N (also equivalent to the speed of the encoder) is:

the pulse width of Z is only half of that of AB, so that the counting time length T of the pulse of Z is obtained_ZComprises the following steps:

in conclusion, the device detects A, B pulses to compensate the lost part of the Z pulse and eliminate the lost fault of the Z pulse; even if the Z pulse is lost, the Z signal can be compensated, the implementation is easy, the cost is low, the shutdown fault of the fan caused by the Z pulse loss condition is reduced, and the grid-connected power generation rate is improved.

While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. Various modifications and alterations to this invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be determined from the following claims.