Non-contact transmission security chain and signal transmission method thereof

Abstract

The application provides a kind of non-contact transmission safety chain and its signal transmission method, comprising: input detection is carried out to the stator side and the multiple safety chain ends of rotor side, and the input condition of each safety chain end is obtained;The input condition of each safety chain end is logically arbitrated, and the signal after logical arbitration of each safety chain end is matrix encoded;The encoded matrix is serially packed, and full-duplex communication transmission is carried out through non-contact slip ring;The matrix after transmission is serially unpacked, and decoded, to obtain the decoded matrix;The decoded matrix is logically arbitrated, and is output to the other end of each safety chain respectively, according to the logical arbitration result, to the other end of the output drive signal of this safety chain, and driving output is carried out.

Description

Technical Field

[0001] This invention relates to the field of safety chain systems, specifically to a non-contact safety chain and its signal transmission method. Background Technology

[0002] A safety chain is a series-connected safety control loop. Several safety relays are connected in series in the input circuit, and the output circuit can control various devices. In the event of a partial fault, the entire loop can be disconnected to prevent the fault from escalating and reduce losses. Safety chain systems typically also have several auxiliary signals to indicate which specific modules have failed.

[0003] Wind turbine generator sets mainly consist of pitch safety chains and control safety chains. The pitch safety chain primarily comprises the nacelle PLC and pitch communication module, emergency stop switch, hub PLC, limit switches, pitch driver, hub communication module, and pitch enable switch. If any of these modules detects a fault, the safety chain will be disconnected, causing the hub to retract the pitch in an emergency.

[0004] Because the hub rotates continuously during normal wind turbine operation, the signal from the safety chain from the nacelle to the hub must be converted by slip rings. The quality of the signal transmitted by the slip rings determines the reliability of the safety chain. If the safety chain fails to disconnect in time, it can damage components at best, and cause the hub to detach or even the tower to collapse at worst. If the safety chain accidentally disconnects during normal power generation, power generation will be impossible, wasting maintenance costs and resulting in a loss of power output.

[0005] The wind turbine control safety chain mainly consists of a tower base PLC and communication module and emergency stop switch, a nacelle PLC and communication module and emergency stop switch, yaw module, brake module, generator module, vibration module, main power supply module, converter module, etc. Its principle is exactly the same as the pitch safety chain.

[0006] Because wind turbines need to be aligned with the wind direction to generate electricity, the connection between the nacelle and the tower can be rotated, i.e., yaw. Early wind turbines mostly used a 750° limit yaw, with cables and signal lines having a certain margin to allow for twisting more than 750°. This meant that if the limit switch failed or yawed too frequently, it would lead to cable breakage, causing significant damage. Furthermore, if the turbine had already yawed 740° (actually 20° to the wind), then needing to yaw 30° to the wind would require a reverse 350° yaw, which was extremely inefficient. Therefore, newer large-megawatt wind turbines use slip ring connections for yaw, allowing for continuous rotation and improved efficiency. This means the entire control safety chain of the wind turbine also heavily relies on slip rings.

[0007] Currently, contact slip rings are commonly used for signal transmission. Contact slip rings transmit signals through the sliding friction between the ring track and the slider. However, contact slip rings have certain disadvantages: poor contact due to wear; instability of the reference ground due to interference; the more channels there are, the lower the reliability and the larger the size; incorrect wiring can burn out the equipment, etc. Summary of the Invention

[0008] To address the above problems, this invention provides a non-contact safety chain and its signal transmission method.

[0009] To achieve the above objectives, the present invention provides the following technical solution.

[0010] A method for transmitting safety chain signals without contact includes the following steps:

[0011] Signal input detection is performed on the stator side and the rotor side of the multiple safety chain terminals to obtain the high and low level input status of each safety chain terminal;

[0012] Logical arbitration is performed on the inputs of each security chain, and matrix encoding is performed on the signals after logical arbitration of each security chain.

[0013] The encoded matrix is ​​serially packaged and transmitted via full-duplex communication through a contactless communication slip ring.

[0014] The transmitted matrix is ​​serially unpacked and decoded to obtain the decoded matrix;

[0015] The decoded matrix is ​​logically arbitrated and output to the output of each security chain. Based on the logical arbitration result, a drive signal is output to the output of that security chain, and the drive output is performed.

[0016] The logical arbitration includes:

[0017] When the input detection identifies a high level, it is then processed through logic arbitration and sent to the matrix encoding signal CO. n =1, output drive signal D to the end of the safety chain. n =0, where n is the number of the end of the safety chain;

[0018] When the input detection identifies a low level, it is then processed through logic arbitration and sent to the matrix encoding signal CO. n =0, output drive signal D to the end of the safety chain. n =0.

[0019] Preferably, the input detection specifically includes:

[0020] Input detection is processed by limiting, filtering, and Schmitt triggering.

[0021] Preferably, each of the safety chain terminals is an input to a multiphase rectifier circuit used to obtain DC power, and the safety chain supports additional power supply.

[0022] Preferably, it further includes:

[0023] By analyzing the high and low levels of various signals on the stator and rotor sides of the non-contact slip ring, it can be determined whether the safety chain is closed, open, or short-circuited.

[0024] A safety chain, comprising:

[0025] Multiple terminals are connected to the stator side and the rotor side respectively;

[0026] Two sets of symmetrical safety chain transmission modules; each set of safety chain transmission modules includes:

[0027] Multiple input detection modules are electrically connected to multiple terminals on the same side to detect the voltage connected to the terminals and convert it into high and low levels.

[0028] The microcontroller's I / O ports are electrically connected to multiple sets of input detection modules, which are used to perform logical arbitration on the input status of each safety chain end, perform matrix encoding, and then serially package the encoded data.

[0029] Multiple sets of high-side switches are electrically connected to multiple terminals on the same side and to the I / O ports of the microcontroller, respectively, to output drive to multiple terminals on the same side according to the signals decoded and logically arbitrated by the microcontroller.

[0030] A non-contact slip ring, comprising a stator and a rotor for non-contact communication; the stator and rotor are respectively connected to microcontrollers on both sides via serial communication.

[0031] The beneficial effects of this invention are:

[0032] This invention proposes a non-contact safety chain and its signal transmission method. This safety chain has strong anti-interference capability and short latency; (for example, using a fixed speed of 1Mbps and a fixed frame length of 8 bytes full-duplex transmission, more than 100 frames can be transmitted every 10ms. Thus, as long as one frame out of 100 frames is successfully transmitted, the transmission latency will not exceed 10ms. The specific parameter combinations mentioned above can be adjusted and set according to the actual situation).

[0033] This safety chain uses contactless transmission, isolating interference between the two sides;

[0034] This safety chain does not transmit a reference ground, thus greatly improving stability and reliability;

[0035] This safety chain has advantages such as automatic signal direction determination and automatic protection against output short circuits.

[0036] This safety chain can transmit up to 12 signals simultaneously, reducing the size and weight of the slip ring. Attached Figure Description

[0037] Figure 1 This is a block diagram of a non-contact safety chain according to an embodiment of the present invention;

[0038] Figure 2 This is a hardware block diagram of a contactless safety chain according to an embodiment of the present invention;

[0039] Figure 3 This is an internal equivalent circuit diagram of the high-side switch according to an embodiment of the present invention;

[0040] Figure 4 This is an input detection circuit diagram according to an embodiment of the present invention;

[0041] Figure 5 This is a multiphase rectifier circuit diagram according to an embodiment of the present invention. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0043] Example 1

[0044] The present invention provides a method for transmitting safety chain signals non-contactly, such as... Figure 1-2 As shown (the cabin side and the wheel hub side are the same; this is just one side shown).

[0045] Includes the following steps:

[0046] S1: Perform input detection on the multiple safety chain ends on the nacelle side and the wheel hub side to obtain the input status of each safety chain end;

[0047] S2: Perform logical arbitration on the input conditions of each security chain endpoint, and perform matrix encoding on the signals after logical arbitration of each security chain endpoint; the logical arbitration includes:

[0048] When the input detection identifies a high level, it is then processed through logic arbitration and sent to the matrix encoding signal CO. n =1, output drive signal D to the end of the safety chain. n =0, where n is the number of the end of the safety chain;

[0049] When the input detection identifies a low level, it is then processed through logic arbitration and sent to the matrix encoding signal CO. n =0, output drive signal D to the end of the safety chain. n =0;

[0050] S3: The encoded matrix is ​​serially packaged and transmitted via full-duplex communication through a non-contact slip ring;

[0051] S4: Serially unpack the transmitted matrix and decode it to obtain the decoded matrix;

[0052] S5: Perform logical arbitration on the decoded matrix and output it to the other end of each security chain. Based on the logical arbitration result, output a drive signal to the other end of the security chain and perform the drive output.

[0053] Specifically, the logical arbitration is analyzed as follows:

[0054] 1. First type, normal wiring

[0055] The signal flow involves both input and output. Considering the perfect symmetry between the nacelle and hub sides, and without loss of representativeness, we assume that nacelle-side A is the input and hub-side B is the output, and that they are connected to the nth channel. The analysis begins below:

[0056] Here, we must consider a total of four scenarios: safety chain closure and disconnection.

[0057] 1.1 Safety chain closure

[0058]

[0059] ① and ② are transient states, while ③ and ④ are completely identical states, indicating that the state has entered a steady state.

[0060] Lookup table method: All signals except the input signal are initially set to 0. At each step, the arbitration logic table is consulted for both the stator side (A) and the rotor side (B) to obtain the result. Sn, Dn, and CIn are the inputs, and Sn, Dn, and COn are the outputs for the next step. A.COn is equal to B.CIn in the next step, and B.COn is equal to A.CIn in the next step (using full-duplex communication; see "Signal Transmission Process" for details). The same applies below.

[0061] 1.2 Safety chain input disconnected

[0062]

[0063] ① and ② are transient states, while ③ and ④ are completely identical states, indicating that the state has entered a steady state.

[0064] 1.3 Safety chain output disconnected

[0065] The transition state is the same as when the safety chain is closed, but the next-level safety chain module detects that the safety chain is always at a low level.

[0066] 1.4 Safety chain disconnected at both ends

[0067] The same applies as when the safety chain input is disconnected, and the next-level safety chain module detects that the safety chain is always at a low level.

[0068] 2. The second type is incorrect wiring.

[0069] 2.1 Input connected to input

[0070]

[0071] ① and ② are transient states, while ③ and ④ are completely identical states, indicating that the state has entered a steady state.

[0072] 2.2, Output connected to output

[0073]

[0074]

[0075] ① and ② are in the same state and directly enter a steady state.

[0076] The third type of output short circuit

[0077] 3.1. Input high, output short-circuited to ground

[0078]

[0079] ① and ② are transient states, while ③ to ⑤ constitute a dynamic cycle, representing output fault states. Because the use of MOSFETs for switching results in fast switching speed and includes internal output protection, the possibility of burning out the equipment due to direct connection will not occur!

[0080] 3.2 When the input is low (i.e., disconnected), the output is short-circuited to high.

[0081]

[0082] ① and ② are transient states, while ③ and ④ are completely identical states, indicating that the state has entered a steady state.

[0083] Here, the system considers the rotor side as the input and the stator side as the output, which is exactly the same as the effect of a direct connection.

[0084] In this embodiment, the signal transmission process is described in detail below.

[0085] This example uses a safety chain loop and two signal indicators.

[0086]

[0087] Signal processing

[0088] 1.1. A.S1 input is 24V; after input detection and recognition, it is identified as high level, i.e., A.S1=1; logic arbitration is performed to output two branches, one branch is sent to the matrix encoding as A.CO1=1, and the other branch is sent to the output driver A.D1=0;

[0089] 1.2. A.S2 is a temporary output of 0V; after input detection and identification, it is identified as a low level, i.e., A.S2=0; logic arbitration is performed to output two branches, one branch is sent to the matrix encoding as A.CO2=0, and the other branch is sent to the output driver A.D2=0;

[0090] 1.3. A.S3 grounding is 0V; after input detection and identification, it is identified as low level, i.e., A.S3=0; logic arbitration is performed to output two branches, one branch sends matrix encoding as A.CO3=0, and the other branch sends output driver A.D3=0;

[0091] 1.4. A.S4 is a temporary output of 0V; after input detection and identification, it is identified as a low level, i.e., A.S4=0; logic arbitration is performed to output two branches, one branch is sent to the matrix encoding as A.CO4=0, and the other branch is sent to the output driver A.D4=0;

[0092] 1.5. A.S5 is a temporary output of 0V; after input detection and identification, it is identified as a low level, i.e., A.S5=0; logic arbitration is performed to output two branches, one branch is sent to the matrix encoding as A.CO5=0, and the other branch is sent to the output driver A.D5=0;

[0093] 1.6 B.S1 is a temporary output of 0V; after input detection and identification, it is identified as a low level, i.e., B.S1=0; logic arbitration is performed to output two branches, one branch is sent to the matrix encoding as B.CO1=0, and the other branch is sent to the output driver B.D1=0;

[0094] 1.7. B.S2 is shorted to the B.S1 input and temporarily 0V is detected; after input detection, it is identified as low level, i.e., B.S2=0; logic arbitration is performed to output two branches, one branch is sent to the matrix encoding as B.CO2=0, and the other branch is sent to the output driver B.D2=0;

[0095] 1.8. B.S3 grounding is 0V; after input detection and identification, it is identified as low level, i.e., B.S3=0; logic arbitration is performed to output two branches, one branch sends matrix encoding as B.CO3=0, and the other branch sends output driver B.D3=0;

[0096] 1.9. B.S4 input is 24V; after input detection and recognition, it is identified as high level, i.e., B.S4=1; logic arbitration is performed to output two branches, one branch is sent to the matrix encoding as B.CO4=1, and the other branch is sent to the output driver B.D4=0;

[0097] 1.10. B.S5 input is disconnected; after input detection and identification, it is identified as low level, i.e., B.S5=0; logic arbitration is performed to output two branches, one branch sends matrix encoding as B.CO5=0, and the other branch sends output driver B.D5=0;

[0098] At this time, we get

[0099] stator signal A.CO1 A.CO2 A.CO3 A.CO4 A.CO5 Logic Level 1 0 0 0 0 Rotor signal B.CO1 B.CO2 B.CO3 B.CO4 B.CO5 Logic Level 0 0 0 1 0

[0100] Perform matrix encoding (the method is not unique; this is just a simple example).

[0101] Connect the above signals together from least significant bit to most significant bit. Fill any missing bits with zeros.

[0102] A.CO = 100000000000, grouped into 3-digit groups, and then XORed within each group to get 1000.

[0103] B.CO = 000100000000, grouped into 3-bit groups, and then XORed within each group to get 0100.

[0104] Then, the result of the XOR operation is concatenated with the preceding concatenation string to obtain the result.

[0105] A.COB = 1000000000001000 = 80 08 encoding results in 2 bytes of data (hexadecimal representation).

[0106] B.COB = 0001000000000100 = 10 04, which is encoded as 2 bytes of data (hexadecimal representation).

[0107] Perform serial packetization (the communication protocol is not unique; this example illustrates one feasible solution).

[0108] Synchronization bit Baotou data check wrap tail Stator transmission 1010101010101010(=A0 A0) FE 80 08 7F F7 0A Rotor sending 1010101010101010(=A0 A0) FE 10 04 EF FB 0A

[0109] The verification here uses bitwise inversion of the data. The algorithm is simple and highly reliable, and it is often used in control communication with relatively little data.

[0110] Communication transmission

[0111] This system uses contactless full-duplex communication at a speed of 1 Mbps (this speed provides stable transmission with less interference in contactless systems), and it only takes 88 µs to transmit one frame.

[0112] Perform serial unpacking (the reverse process of packing).

[0113] Unpacking yields: A.CIB = 10 04

[0114] B.CIB = 80 08

[0115] Perform matrix decoding (the inverse process of matrix encoding).

[0116] A.CIB=10 04=0001000000000100

[0117] B.CIB=80 08=1000000000001000

[0118] Decoding yields: A.CI = 00010

[0119] B.CI = 10000

[0120] At this point we get

[0121]

[0122]

[0123] Second signal processing (same as the original signal processing procedure)

[0124]

[0125] Repeat the above process to finally obtain

[0126] enter 24V A.S1 Output 24V B.S1 Output 24V A.S2 enter Shorting is the same as above. B.S2 Grounding 0V A.S3 Grounding 0V B.S3 Output 24V A.S4 enter 24V B.S4 Output 0V A.S5 enter disconnect B.S5

[0127] Conclusion: The results show that the contactless communication safety chain is consistent with that of direct wiring. The delay is <100µs, and even with short-circuiting the return signal, the total delay is <200µs. This fully meets the requirements for power relays (<10ms) and control relays (<1ms). It also meets the requirement for fan control delay (<20ms).

[0128] The hardware in this embodiment includes:

[0129] 1. 12-channel terminals J1~J12

[0130] Select terminals with a rated voltage of 5A and a withstand voltage of 50V or higher for each circuit, and with easy wiring.

[0131] 2. High-side switches U3, U4, U5

[0132] In this embodiment, the VNQ5050 high-side driver switch is selected. Each chip contains four high-side output drivers and features overvoltage, overcurrent, overheat, and short-circuit protection. The simplified internal equivalent circuit is as follows: Figure 3 As shown;

[0133] Specifically, when the input IN is low, the output OUT is turned off; when the input IN is high, the output OUT is turned on, i.e., the output VCC is displayed.

[0134] The output OUT here is connected to the Jn terminal, as shown in the schematic diagram. Figure 1 In Sn, we can see a reverse parasitic diode between VCC and OUT, which is used in multiphase rectification.

[0135] 3. Input detection

[0136] There are 12 input detection channels, each circuit is as follows: Figure 4 As shown;

[0137] like Figure 4 R1 and R2 form a voltage divider circuit, with the output OUT approximately equal to 1 / 5 of the input IN. R1 and C1 form a filter circuit, and D1 limits the voltage to 5V. Generally, analog input to logic converters require a Schmitt trigger to prevent frequent input jitter from causing overheating or blockage in subsequent stages. No Schmitt triggers are added here because almost all I / O ports of the microcontroller U1 have Schmitt triggers.

[0138] 4. Microcontroller U1

[0139] In this embodiment, the STM8S103 is selected, with a 16MHz clock, 3-5.5V power supply, up to 28 I / O ports, a built-in watchdog timer, and a full-duplex serial port. Furthermore, each I / O port, except for the clock, has a Schmitt trigger for input, fully meeting our requirements.

[0140] The microcontroller software includes logic arbitration, matrix encoding / decoding, and serial port packing / unpacking functions.

[0141] 5. RS422 interface U2

[0142] In this embodiment, the ISL8490 industrial-grade RS485 / 422 interface chip with a maximum speed of 5Mbps is selected. It has low power consumption and an electrostatic discharge protection level of up to 7kV. It completes the conversion of serial port TTL level to RS422 differential level to realize full-duplex serial communication drive.

[0143] 6. Multiphase rectifier circuit

[0144] like Figure 5 As shown, D1 to D12 here are parasitic diodes between VCC and OUT in the high-side drive switch. When there is a 24V input, regardless of whether S1 to S12 are energized (none exceeding 24V), D1 to D12 are reverse-biased and cut off. When the 24V input is not connected, disconnected, or the power supply is insufficient (<24V), the diodes energized in S1 to S12 will conduct in the forward direction to supply power to VCC and 24V. The resettable fuse F1 provides overcurrent protection for 24V.

[0145] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for transmitting safety chain signals non-contactly, characterized in that, Includes the following steps: Signal input detection is performed on the stator side and the rotor side of the multiple safety chain terminals to obtain the high and low level input status of each safety chain terminal; Logical arbitration is performed on the inputs of each security chain, and matrix encoding is performed on the signals after logical arbitration of each security chain. The encoded matrix is ​​serially packaged and transmitted via full-duplex communication through a contactless communication slip ring. The transmitted matrix is ​​serially unpacked and decoded to obtain the decoded matrix; The decoded matrix is ​​logically arbitrated and output to the output of each security chain. Based on the logical arbitration result, a drive signal is output to the output of that security chain, and the drive output is performed. The logical arbitration includes: When the input detection recognition is high level, after logic arbitration, the matrix coding signal CO n =1 is sent into the output drive signal D n =0 of the safety chain end, and n is the number of the safety chain end. When the input detection identifies a low level, it is then processed through logic arbitration and sent to the matrix encoding signal CO. n =0, output drive signal D to the end of the safety chain. n =0.

2. The method for transmitting safety chain signals non-contactly according to claim 1, characterized in that, The input detection specifically includes: Input detection is processed by limiting, filtering, and Schmitt triggering.

3. The method for transmitting safety chain signals non-contactly according to claim 1, characterized in that, Each of the aforementioned safety chain terminals is an input to a multiphase rectifier circuit used to obtain DC power, and this safety chain supports additional power supply.

4. The method for transmitting safety chain signals non-contactly according to claim 1, characterized in that, Also includes: By analyzing the high and low levels of various signals on the stator and rotor sides of the non-contact slip ring, it can be determined whether the safety chain is closed, open, or short-circuited.

5. A safety chain, characterized in that, include: Multiple terminals are connected to the stator side and the rotor side respectively; Two sets of symmetrical safety chain transmission modules; Each of the security chain transmission modules includes: Multiple input detection modules are electrically connected to multiple terminals on the same side to detect the voltage connected to the terminals and convert it into high and low levels. The microcontroller has its I / O ports electrically connected to multiple sets of input detection modules. It is used to perform logical arbitration on the input status of each security chain end, and to perform matrix encoding. After encoding, the data is serially packaged. The microcontroller is also used to unpack and decode the received serial data, and to output drive control signals after performing logical arbitration based on the decoding results. Multiple sets of high-side switches are electrically connected to multiple terminals on the same side and to the I / O ports of the microcontroller, respectively, to output drive to multiple terminals on the same side according to the signals decoded and logically arbitrated by the microcontroller. A non-contact slip ring, comprising a stator and a rotor for non-contact communication; the stator and rotor are respectively connected to microcontrollers on both sides via serial communication. The logical arbitration includes: When the input detection identifies a high level, it is then processed through logic arbitration and sent to the matrix encoding signal CO. n =1, output drive signal D to the end of the safety chain. n =0, where n is the number of the end of the safety chain; When the input detection identifies a low level, it is then processed through logic arbitration and sent to the matrix encoding signal CO. n =0, output drive signal D to the end of the safety chain. n =0.

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