A PHM-oriented electromagnetic relay online state detection device and method

Abstract

The invention discloses an electromagnetic relay online state detection device and method for PHM, and relates to the technical field of state detection. The invention connects a sampling resistor R3 in series in a coil loop of an electromagnetic relay, and simultaneously connects a resistor R4 and a resistor R5 in parallel; connects a sampling resistor R2 in series in a load loop of the electromagnetic relay, and simultaneously connects a resistor R6 and a resistor R7 in series; and arranges an optocoupler element U2, an optocoupler element U3 and an optocoupler element U4 in the circuit; during detection, the on-off of the electromagnetic relay is controlled by the optocoupler element U2, the optocoupler element U3 and the optocoupler element U4, and the voltages at both ends of the coil and the contact are detected; the coil current, coil resistance, load current, contact resistance, pull-in time and release time of the electromagnetic relay are measured by the cooperation of the sampling resistor R3 with the resistor R6 and the resistor R7, and the cooperation of the sampling resistor R2 with the resistor R6 and the resistor R7, so that the electromagnetic relay can be detected during the normal operation of the electromagnetic relay without affecting the normal operation of the electromagnetic relay.

Description

Technical Field

[0001] The present invention relates to the technical field of state detection, and in particular to an electromagnetic relay online state detection device and method for PHM. Background Art

[0002] Electromagnetic relay is a commonly used control element in electrical systems. It drives the movement of contacts by controlling the electromagnetic force generated by the current passing through the coil to realize the on-off function of the circuit. It has the characteristics of input and output signal isolation, strong load capacity, and strong anti-interference ability. It has been widely used in various electrical systems to complete functions such as logic control, signal isolation, and load driving. Since the electromagnetic relay structure has both circuits and mechanical moving parts, it will fail due to performance degradation during long-term use, thereby causing system functional failure. For aircraft, if a system functional failure occurs in the air, it may lead to serious consequences or even catastrophic accidents.

[0003] In the detection and prevention of electromagnetic relay faults, the prognostics and health management (PHM) technology is often used. This technology is a technology for active prevention, advance prediction and comprehensive management of equipment failures and failures. It can timely analyze the current status of components, equipment or systems according to the degradation law and real-time monitoring data of components, equipment or systems, and discover and issue alarms in time before the failure occurs, reminding maintenance and replacement of "sub-healthy" failed parts, so as to avoid the occurrence of failures. The basis for the implementation of PHM technology is to be able to monitor and record the state parameters of the system in real time without interfering with the normal operation of the system, and analyze and judge in combination with known degradation models, and give alarm information in time. Therefore, to apply PHM technology to electromagnetic relays, it is necessary to obtain relevant parameter data of a large number of electromagnetic relay samples throughout their life cycle through experiments, and analyze and study the degradation law based on these data, build a degradation model, and then write the mature degradation model into the controller, so as to realize the analysis, judgment and alarm of the status; and make maintenance management decisions on this basis, replace relays in sub-healthy states in time, reduce the probability of failure of electromagnetic relays during normal operation, and thus reduce the serious consequences of failure of the entire system due to relay failure.

[0004] At present, electromagnetic relay parameter measurement systems are divided into: the first type is mainly used for quality inspection of electromagnetic relays after production or maintenance. This type of system often uses larger detection equipment because it needs to detect many parameters, and an excitation voltage is injected during the detection process; the second type is mainly used to study the degradation law of electromagnetic relays. This type of equipment needs to detect the mechanical parameters, electrical parameters, time parameters, displacement, acceleration and speed of the electromagnetic relay, which makes its detection equipment more complicated.

[0005] However, the parameter measurement systems mentioned above are all offline detections, which require the electromagnetic relay to be disassembled and tested. However, offline detection requires the equipment to be suspended, making it difficult to detect the state of the electromagnetic relay during operation, and the electromagnetic relay may be damaged internally during detection. Therefore, current detection methods are difficult to detect the long-term operating state of the electromagnetic relay. Summary of the invention

[0006] The embodiments of the present invention provide an electromagnetic relay online state detection device and method for PHM, which can solve the problem in the prior art that it is difficult to detect the long-term operating state of the electromagnetic relay.

[0007] The embodiment of the present invention provides an electromagnetic relay online state detection device for PHM, including a relay state control detection module;

[0008] The relay state control detection module includes: a sampling resistor R2, a sampling resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, an AD chip, an optocoupler U2, an optocoupler U3 and an optocoupler U4; one end of the sampling resistor R3 and one end of the resistor R5 are simultaneously connected to one end of the relay coil, the other end of the sampling resistor R3 is connected to one end of the optocoupler U3 and one end of the power supply, the other end of the optocoupler U3 is connected to the AIN4 end of the AD chip, the other end of the resistor R5 is connected to the resistor R4, the other end of the resistor R4 is connected to one end of the optocoupler U2 and the other end of the relay coil, and the other end of the optocoupler U2 is connected to the other end of the power supply;

[0009] One end of the relay connected to the load is connected to one end of the sampling resistor R2, the other end of the sampling resistor R2 is simultaneously connected to one end of the resistor R7 and one end of the optocoupler U4, the other end of the resistor R7 is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the other end of the load, the other end of the optocoupler U4 is connected to one end of the resistor R6 connected to the load, and the other end of the optocoupler U4 is also connected to the AIN1 end and the AIN3 end of the AD chip.

[0010] Preferably, the resistance value of the sampling resistor R3 is 10Ω, the resistance value of the resistor R4 is 27KΩ, and the resistance value of the resistor R5 is 1KΩ.

[0011] Preferably, the resistance of the sampling resistor R2 is 0.05Ω, the resistance of the resistor R6 is 27KΩ, and the resistance of the resistor R7 is 4.7KΩ.

[0012] Preferably, the optical coupling element U2 is used to control the on / off of the relay coil circuit to control the closing and opening of the relay;

[0013] The optical coupler element U3 is used to measure the voltage across the coil;

[0014] The optocoupler element U4 is used to measure the voltage across the load.

[0015] Preferably, it also includes a microcontroller module, a power module, an AD acquisition module, a buzzer, a display module, a key input module, a storage module and a wifi communication module;

[0016] The microcontroller module is used to control the connection and disconnection of the electromagnetic relay according to the set frequency, detect the pull-in and release time of the electromagnetic relay, and control the AD acquisition module to detect the coil current, coil resistance, load current and contact resistance;

[0017] The power supply module is used to convert the input DC voltage into 5V and 3.3V and supply power to each module;

[0018] The buzzer is connected to the microcontroller module. When the parameter exceeds the warning value or an abnormality occurs, the electromagnetic relay enters a quasi-fault state, and the microcontroller module drives the buzzer to sound an alarm;

[0019] The display module is connected to the microcontroller module, and the display module is used to display the measurement parameters;

[0020] The key input module is connected to the microcontroller module, and the key input module is used for controlling and entering information;

[0021] The storage module is connected to the microcontroller module, and the storage module is used to store historical parameters of the electromagnetic relay;

[0022] The wifi communication module is connected to the microcontroller through the RS232 bus, and is used to receive the state parameters of the electromagnetic relay and convert them into wifi signals for transmission.

[0023] The embodiment of the present invention further provides a detection method of an electromagnetic relay online state detection device for PHM, comprising the following steps:

[0024] When the state of the electromagnetic relay is detected, the optocoupler element U2 drives the coil circuit of the electromagnetic relay to conduct, so that the electromagnetic relay is closed;

[0025] The coil current and coil resistance of the electromagnetic relay are obtained by measuring the sampling resistor R3;

[0026] The load current and contact resistance of the electromagnetic relay are obtained by measuring the sampling resistor R2;

[0027] The closing time and the releasing time of the electromagnetic relay are obtained through the on and off states of the optical coupling elements U3 and U4;

[0028] The operating state of the electromagnetic relay is determined by obtaining the coil current, coil resistance, load current, contact resistance, pull-in time and release time of the electromagnetic relay.

[0029] Preferably, the coil current and coil resistance of the electromagnetic relay are obtained by:

[0030] When current flows through the electromagnetic relay coil, the coil current is measured by collecting the voltage across the sampling resistor R3 and the resistance value of the sampling resistor R3;

[0031] After dividing the coil voltage by resistor R4 with a resistance value of 27KΩ and resistor R5 with a resistance value of 1KΩ, the voltage across resistor R5 is collected. The ratio of the voltage across resistor R4 to the voltage across resistor R5 is consistent with the ratio of the resistance value of resistor R4 to the resistance value of resistor R5. The coil voltage is 28 times the voltage across resistor R5, and the coil resistance is measured by the coil voltage and coil current.

[0032] Preferably, the load current and contact resistance of the electromagnetic relay are obtained by:

[0033] When current flows through the load circuit of the relay, the load current is measured by collecting the voltage across the sampling resistor R2 and the resistance across the sampling resistor R2;

[0034] After dividing the load voltage by resistor R6 with a resistance value of 27KΩ and resistor R7 with a resistance value of 4.7KΩ, the voltage across the resistor R7 is collected as U9. According to the resistance values ​​of resistors R6 and R7, the divided voltage is U9*31.7 / 4.7, and the voltage across the sampling resistor R2 is subtracted from the divided voltage to obtain the load voltage. The contact resistance is measured by the load voltage and load current.

[0035] Preferably, the acquisition of the pull-in time and the release time of the electromagnetic relay includes:

[0036] When the working state of the optocoupler element U3 changes from off to on, the electromagnetic relay is closed at this moment, and the relay closing time is recorded as t1; the electromagnetic relay coil passes current, so that the iron core of the electromagnetic relay is magnetized and the contacts are attracted and closed, and the working state of the optocoupler element U4 changes from on to off, and the time at this moment is recorded as t2, and the electromagnetic relay pull-in time is obtained by subtracting t1 from t2;

[0037] When the optocoupler U2 is disconnected, the power supply of the electromagnetic relay coil is disconnected, and the working state of the optocoupler U3 changes from on to off. At this moment, the relay is disconnected, and the relay disconnection time is recorded as t3; the electromagnetic relay coil does not adsorb the contacts, causing the contacts to be disconnected, and the working state of the optocoupler U4 changes from off to on. The time at this moment is recorded as t4, and the release time of the electromagnetic relay is obtained by subtracting t3 from t4.

[0038] The embodiment of the present invention provides an electromagnetic relay online state detection device and method for PHM. Compared with the prior art, the beneficial effects thereof are as follows:

[0039] The present invention connects a sampling resistor R3 in series in the coil loop of the electromagnetic relay, and simultaneously connects a resistor R4 and a resistor R5 in parallel; connects a sampling resistor R2 in series in the load loop of the electromagnetic relay, and simultaneously connects a resistor R6 and a resistor R7 in series; and sets an optocoupler U2, an optocoupler U3 and an optocoupler U4 in the circuit; during specific detection, the on-off of the electromagnetic relay is controlled by the optocoupler U2, the optocoupler U3 and the optocoupler U4, and the voltages at both ends of the coil and the contact are detected; at the same time, the coil current, coil resistance, load current, contact resistance, pull-in time and release time of the electromagnetic relay are measured by the cooperation of the sampling resistor R3 with the resistor R6 and the resistor R7, and the cooperation of the sampling resistor R2 with the resistor R6 and the resistor R7, and the real-time operating state of the electromagnetic relay is judged according to the coil current, coil resistance, load current, contact resistance, pull-in time and release time collected in real time; during the entire detection stage, the present invention can detect the electromagnetic relay for a long time during which the electromagnetic relay is working normally, without affecting the normal operation of the electromagnetic relay. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A schematic diagram of the overall architecture of a degradation test device for an electromagnetic relay online state detection device for PHM provided by an embodiment of the present invention;

[0041] Figure 2 A schematic diagram of degradation test control and time parameter detection principle of an electromagnetic relay online state detection device for PHM provided by an embodiment of the present invention;

[0042] Figure 3 A schematic diagram of the degradation test data collection principle of an electromagnetic relay online state detection device for PHM provided by an embodiment of the present invention;

[0043] Figure 4 A schematic diagram of the workflow of an accelerated degradation test control detection device for an electromagnetic relay online state detection device and method for PHM provided by an embodiment of the present invention;

[0044] Figure 5A schematic diagram of a software interface of an accelerated degradation test data monitoring terminal of an online state detection device for an electromagnetic relay for PHM provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0045] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0046] See also Figure 1 The embodiment of the present invention provides an electromagnetic relay online state detection device for PHM, including: a relay board, a load resistor, a load power supply, a control detection device power supply, an accelerated degradation test control detection device, a wireless router and an accelerated degradation test data monitoring terminal; wherein the relay board is used to install the electromagnetic relay under test; the load resistor and the load power supply are used to build the load circuit of the electromagnetic relay and provide the working current; the control detection device power supply is used to power the accelerated degradation test control detection device; the accelerated degradation test control detection device is used to control the on and off of the electromagnetic relay, and at the same time detect the state parameters of the relay, and store, display and send them to the wireless router with a wireless wifi signal; the wireless router is a relay station for the wireless wifi signal, which supports receiving electromagnetic relay parameters sent by multiple accelerated degradation test control detection devices at the same time, and forwarding them to the accelerated degradation test data monitoring terminal for processing and display; the accelerated degradation test data monitoring terminal is a computer with accelerated degradation test data monitoring software installed inside, which is used to collect all relay state parameters sent by the accelerated degradation test control detection device, and can intuitively display the current and historical state parameter information of the relay while analyzing and storing them.

[0047] The main parameters acquired by the accelerated degradation test control detection device include the number of times the electromagnetic relay is pulled in, coil current, coil resistance, load current, load resistance, contact resistance, pull-in time and release time; the number of times the electromagnetic relay is pulled in indicates the number of times the relay works, and the number of times the electromagnetic relay is pulled in increases once each time the power is turned on; specifically, the measurement process of each parameter is as follows:

[0048] Coil current measurement: A sampling resistor R3 with a resistance of 10 ohms is connected in series in the coil loop. The voltage across the sampling resistor is collected by a high-precision AD. The coil current can be obtained by dividing this voltage by the resistance of the sampling resistor R1.

[0049] Coil resistance measurement: Based on the measurement of the coil current, the voltage value at both ends of the coil is measured through an AD, and finally the coil resistance is obtained by calculating the ratio of this voltage to the coil current.

[0050] Load current measurement: A high-precision, low-temperature drift sampling resistor R2 with a resistance of 50 milliohms is connected in series in the load circuit loop. The voltage across the sampling resistor R2 is collected using a high-precision AD chip, and then divided by the resistor R2 to obtain the load current value.

[0051] Contact resistance measurement: During the measurement process, the contact resistance is not measured directly, but is calculated by measuring the voltage value across the contacts after the electromagnetic relay contacts are closed; based on the known load current, a high-precision AD is used to collect the voltage value across the contacts, and this voltage is divided by the load current to obtain the contact resistance value.

[0052] Measurement of pull-in time and release time: Pull-in time and release time are time parameters of electromagnetic relays. Since time parameters require a faster test speed, the control detection device should be designed with a processor with better performance. By detecting the voltage signal on the winding coil and the contact closure signal, the time from the driving voltage signal on the coil to the contact closure of the electromagnetic relay is calculated, which is the pull-in time. At the same time, by detecting the disconnection of the voltage signal on the winding coil and the disconnection signal of the contact, the time from the loss of the driving voltage signal on the coil to the disconnection of the contacts of the electromagnetic relay is calculated, and the release time of the electromagnetic relay is calculated.

[0053] Specifically:

[0054] The accelerated degradation test control and detection device is a printed circuit board, on which are installed a microcontroller module, a power module, a relay state control and detection module, an AD acquisition module, a buzzer, a display module, a key input module, a storage module and a wifi communication module; wherein the power module is used to convert the input DC voltage into 5V and 3.3V, and provide a DC working voltage for various chips in the control and detection device; three optocouplers are used in the relay state control and detection module, one of which is used to drive the on and off of the electromagnetic relay under the control of the controller, and the other two are used to respectively detect the voltages at both ends of the coil and the electromagnetic relay contacts, so as to determine whether the electromagnetic relay is driven to be connected. The AD acquisition module uses the ADS1256 chip to collect 4 voltage signals for detecting coil current, coil resistance, load current and contact resistance. The buzzer is used to sound an alarm. When the parameter exceeds the warning value or an abnormality occurs, the relay enters a quasi-fault state, and the microcontroller drives the buzzer to sound an alarm. The display module uses a 256x64 dot matrix display to display the most recently measured parameters. When an abnormal situation such as an alarm occurs, the display can also display relevant information. The key input module consists of 4 independent keys for control and information entry.

[0055] The storage module adopts W25Q128 storage chip, which is used to store the historical parameters of the electromagnetic relay. The storage chip has a storage capacity of 128Mb. In order to improve the storage efficiency and meet the data storage function of the whole life cycle, the data storage format is designed to store the state parameters obtained in each test in a 16-byte data packet. Moreover, during the test, the electromagnetic relay is driven on and off once every 2 seconds, and the state parameters are collected once; however, the degradation process of the electromagnetic relay is very long, and no obvious degradation can be seen in the nearly 10 on and off times. In order to further improve the stability of the data and store parameter data of more test times, the present invention uses a filtering algorithm when storing data, collects nearly 10 test data, then removes the largest two parameters and the smallest two parameters, and then calculates the average of the remaining 6 data, and the obtained data is stored in the memory as the final data of the nearly 10 tests; therefore, according to the capacity of the memory, the number of groups of storable parameters can be calculated as:

[0056] 128Mb / 16B=1048576

[0057] Wherein: B is an 8-bit byte; since a set of data is stored every 10 tests, the number of relay closing tests that can be supported is 10485760 times, which exceeds the life of the electromagnetic relay and meets the data storage function of the entire life cycle. Moreover, calculated based on one closure every 2 seconds, the time that can support the degradation test of the electromagnetic relay is: 10485760*2 / 60 / 60 / 24≈242 days.

[0058] The wifi communication module communicates with the microcontroller via the RS232 bus, receives the status parameter information of the electromagnetic relay, and converts it into a wireless wifi signal to send out.

[0059] The microcontroller module is the core of the control and detection device. The module adopts the STM32F103CB microcontroller to control the connection and disconnection of the electromagnetic relay according to the specified frequency, detect the attraction and release time of the electromagnetic relay, and control the AD acquisition module to detect the coil current, coil resistance, load current and contact resistance.

[0060] Degradation test control and time parameter detection principle Figure 2 As shown; it can be seen that three optocoupler components are installed in the electromagnetic relay state detection module; among them, the optocoupler component U2 with model TLP240GA is used to control the closing and opening of the electromagnetic relay by controlling the on and off of the coil circuit of the electromagnetic relay under the control of the microcontroller; the optocoupler component U3 with model EL3H7 is used to detect the voltage across A1+ and A2-. Since the resistance of the coil sampling resistor R3 is small, it is equivalent to detecting the voltage across the coil, which is used to determine whether the electromagnetic relay has a closing drive signal; the optocoupler component U4 with model EL3H7 is used to detect the voltage across B3 and B5. Since the resistance of the contact sampling resistor R2 is small, it is equivalent to detecting the voltage across the contact, which is used to determine whether the electromagnetic relay is closed.

[0061] When there is no working voltage in the coil, the optocoupler U3 is in the disconnected state. When the accelerated degradation device starts to work, the microcontroller sends a signal to close the optocoupler element U2. At this time, there is working voltage at both ends of the coil, and the optocoupler U9 is turned on. The microcontroller detects that the working state of the optocoupler U3 changes from disconnected to on, and determines that the electromagnetic relay has a closed drive signal at this moment. The microcontroller records the time at this time as t1. Then, since there is current in the coil, the iron core will be magnetized with suction, thereby attracting the contacts to close. When closed, since the contact resistance is very small and the contact sampling resistance is also very small, Figure 2 The voltage between positions B3 and B5 becomes very small, and the optocoupler U4 changes from on to off. The microcontroller detects the change in the state of the optocoupler U4 and records the time at this time as t2. At this time, the electromagnetic relay pull-in time can be obtained by subtracting t1 from t2.

[0062] The microcontroller controls the electromagnetic relay to close for 1 second, and then generates a signal to disconnect the optocoupler element U2, so that the coil power supply is disconnected; the microcontroller detects that the working state of the optocoupler U3 changes from on to off, and determines that the electromagnetic relay has a disconnection drive signal at this moment, and the microcontroller records the time at this time as t3; then, due to the loss of current in the coil, the iron core will no longer absorb the contacts, and under the tension of the spring inside the relay, the contacts are disconnected, and the optocoupler U4 changes from off to on. The microcontroller detects the change in the state of the optocoupler U4 and records the time at this time as t4. At this time, the release time of the electromagnetic relay can be obtained by subtracting t3 from t4; after that, the microcontroller controls the electromagnetic relay to be disconnected for 1 second, and then controls the electromagnetic relay to be periodically closed and disconnected again.

[0063] like Figure 3 As shown, it is a schematic diagram of the degradation test data acquisition principle; it can be seen that the AD acquisition module of the accelerated degradation test control and detection device measures the coil current, coil resistance, load current, and contact resistance parameters after the relay is closed.

[0064] A 10-ohm coil sampling resistor R3 is connected in series in the coil loop of the electromagnetic relay. When there is current in the coil, the microcontroller controls the AIN4 and AIN5 terminals of the AD chip ADS1256 to collect the voltage across the coil sampling resistor R3. The voltage value is divided by the resistance value of R3 (10 ohms) to obtain the current value passing through the coil. At the same time, resistors R4 of 27KΩ and R5 of 1KΩ are connected in series at both ends of the coil. After dividing the coil voltage, the AIN6 and AIN7 terminals of the AD chip ADS1256 collect the voltage. If the collected voltage is U2, the voltage U1 across the coil is 28 times that of U2. Then the coil voltage U1 is divided by the coil current to obtain the coil resistance.

[0065] A 0.05 ohm contact sampling resistor R2 is introduced into the load circuit of the electromagnetic relay. When there is current in the load circuit, the microcontroller controls the AIN2 and AIN3 terminals of the AD chip ADS1256 to collect the voltage U5 across the sampling resistor R2. By dividing this voltage value by the resistance value of R2 (0.05 ohm), the current value passing through the load can be obtained. At the same time, resistors R6 of 27KΩ and R7 of 4.7KΩ are connected in series at the positions B3 and B5 of the load circuit. After the voltage is divided, it is collected by the AIN0 and AIN1 terminals of the AD chip ADS1256. If the collected voltage is U4, the voltage value U3 between points B3 and B5 is U4*31.7 / 4.7, and then the voltage U5 across the contact sampling resistor is subtracted to obtain the voltage U6 across the contact. Then, U6 is divided by the load current to obtain the contact resistance.

[0066] The workflow of the software in the accelerated degradation test control detection device is as follows: Figure 4As shown; when the power is turned on, the control detection device first checks whether the memory is normal. If an abnormality is found, the problem is displayed and the program is terminated. Otherwise, continue to check whether the wifi communication with the monitoring terminal is normal. If a communication abnormality is found, the specific communication problem is displayed and the program is terminated. Otherwise, continue to check whether the control and detection functions of the device are normal. If an abnormality is found, the specific problem is displayed and the program is terminated. Then, drive the electromagnetic relay to close, record the cumulative number of closing times, and measure and store the coil current, coil resistance, load current, contact resistance and pull-in time parameters; after waiting for 1 second, drive the relay to disconnect, measure and store the release time, and send all the acquired data through the wireless wifi signal. Finally, the control detection device will also analyze each parameter. If it exceeds the set threshold, the test will be stopped. Otherwise, continue to drive the electromagnetic relay to close and disconnect, and continuously monitor and record the status parameters of the relay.

[0067] Electromagnetic relay accelerated degradation test data monitoring software Figure 5 As shown in the figure, the software is divided into three areas, namely the relay status selection area, the relay status parameter viewing area and the relay status parameter trend display area; the relay status selection area supports up to 50 relays, and each relay provides a status light. When some status parameters of the relay are close to the warning value, the status light will turn yellow, and when it exceeds the warning value, it will turn red; when a relay is selected, the relay status parameter viewing area will display the coil current, coil resistance, load current, contact resistance, pull-in time and release time and other status parameters of the relay measured recently, and the relay status parameter trend display area will display the historical status parameter curve of the relay, so that the changes of the relevant parameters of the relay can be viewed more intuitively; at the same time, the relay status parameter viewing area also provides a status parameter query function, which can accurately query the status parameters of a certain closure.

[0068] The present invention can monitor the state of the electromagnetic relay when the electromagnetic relay is working normally, without affecting the normal operation of the electromagnetic relay; the present invention is provided with a storage function, that is, an efficient data storage method is designed, which can store more than 1 million sets of parameters; the present invention also adopts wireless wifi signals to transmit data, realizes remote transmission of data, and is convenient for remote observation of test data; the number of closures, coil current, coil resistance, load current, contact resistance, pull-in time and release time of the electromagnetic relay detected by the present invention, these parameters can not only reflect whether the state of the electromagnetic relay is good, but also reflect the degradation of the electromagnetic relay, and can provide an effective data basis for electromagnetic relay state prediction and health management.

[0069] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An electromagnetic relay online status detection device for PHM, characterized in that: include: Relay status control detection module; The relay state control detection module includes: a sampling resistor R2, a sampling resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, an AD chip, an optocoupler U2, an optocoupler U3 and an optocoupler U4; one end of the sampling resistor R3 and one end of the resistor R5 are simultaneously connected to one end of the relay coil, the other end of the sampling resistor R3 is connected to one end of the optocoupler U3 and one end of the power supply, the other end of the optocoupler U3 is connected to the AIN4 end of the AD chip, the other end of the resistor R5 is connected to the resistor R4, the other end of the resistor R4 is connected to one end of the optocoupler U2 and the other end of the relay coil, and the other end of the optocoupler U2 is connected to the other end of the power supply; One end of the relay connected to the load is connected to one end of the sampling resistor R2, the other end of the sampling resistor R2 is simultaneously connected to one end of the resistor R7 and one end of the optocoupler U4, the other end of the resistor R7 is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the other end of the load, the other end of the optocoupler U4 is connected to one end of the resistor R6 connected to the load, and the other end of the optocoupler U4 is also connected to the AD chip AIN1 end and AIN3 end; The optocoupler element U2 is used to control the on / off of the relay coil circuit to control the closing and opening of the relay; the optocoupler element U3 is used to measure the voltage across the coil; the optocoupler element U4 is used to measure the voltage across the load; When the state of the electromagnetic relay is detected, the optocoupler element U2 drives the coil circuit of the electromagnetic relay to conduct, so that the electromagnetic relay is closed; The coil current and coil resistance of the electromagnetic relay are obtained by measuring the sampling resistor R3; The load current and contact resistance of the electromagnetic relay are obtained by measuring the sampling resistor R2; The closing time and the releasing time of the electromagnetic relay are obtained through the on and off states of the optical coupling elements U3 and U4; The operating state of the electromagnetic relay is determined by obtaining the coil current, coil resistance, load current, contact resistance, pull-in time and release time of the electromagnetic relay.

2. The electromagnetic relay online state detection device for PHM according to claim 1, characterized in that: The resistance value of the sampling resistor R3 is 10Ω, the resistance value of the resistor R4 is 27KΩ, and the resistance value of the resistor R5 is 1KΩ.

3. The electromagnetic relay online state detection device for PHM according to claim 1, characterized in that: The resistance value of the sampling resistor R2 is 0.05Ω, the resistance value of the resistor R6 is 27KΩ, and the resistance value of the resistor R7 is 4.7KΩ.

4. The electromagnetic relay online state detection device for PHM according to claim 1, characterized in that: Also includes: Microcontroller module, power module, AD acquisition module, buzzer, display module, key input module, storage module and wifi communication module; The microcontroller module is used to control the connection and disconnection of the electromagnetic relay according to the set frequency, detect the pull-in and release time of the electromagnetic relay, and control the AD acquisition module to detect the coil current, coil resistance, load current and contact resistance; The power supply module is used to convert the input DC voltage into 5V and 3.3V and supply power to each module; The buzzer is connected to the microcontroller module. When the parameter exceeds the warning value or an abnormality occurs, the electromagnetic relay enters a quasi-fault state, and the microcontroller module drives the buzzer to sound an alarm; The display module is connected to the microcontroller module, and the display module is used to display the measurement parameters; The key input module is connected to the microcontroller module, and the key input module is used for controlling and entering information; The storage module is connected to the microcontroller module, and the storage module is used to store historical parameters of the electromagnetic relay; The wifi communication module is connected to the microcontroller through the RS232 bus, and is used to receive the state parameters of the electromagnetic relay and convert them into wifi signals for transmission.

5. The detection method of the electromagnetic relay online state detection device for PHM according to any one of claims 1 to 4, characterized in that: The coil current and coil resistance of the electromagnetic relay are obtained, including: When current flows through the electromagnetic relay coil, the coil current is measured by collecting the voltage across the sampling resistor R3 and the resistance value of the sampling resistor R3; After dividing the coil voltage by resistor R4 with a resistance value of 27KΩ and resistor R5 with a resistance value of 1KΩ, the voltage across resistor R5 is collected. The ratio of the voltage across resistor R4 to the voltage across resistor R5 is consistent with the ratio of the resistance value of resistor R4 to the resistance value of resistor R5. The coil voltage is 28 times the voltage across resistor R5, and the coil resistance is measured by the coil voltage and coil current.

6. The detection method of the electromagnetic relay online state detection device for PHM according to claim 5, characterized in that: The load current and contact resistance of the electromagnetic relay are obtained, including: When current flows through the load circuit of the relay, the load current is measured by collecting the voltage across the sampling resistor R2 and the resistance across the sampling resistor R2; After dividing the load voltage by resistor R6 with a resistance value of 27KΩ and resistor R7 with a resistance value of 4.7KΩ, the voltage across the resistor R7 is collected as U9. According to the resistance values ​​of resistors R6 and R7, the divided voltage is U9*31.7 / 4.7, and the voltage across the sampling resistor R2 is subtracted from the divided voltage to obtain the load voltage. The contact resistance is measured by the load voltage and load current.

7. The detection method of the electromagnetic relay online state detection device for PHM according to claim 5, characterized in that: The acquisition of the pull-in time and the release time of the electromagnetic relay includes: When the working state of the optocoupler element U3 changes from off to on, the electromagnetic relay is closed at this moment, and the relay closing time is recorded as t1; the electromagnetic relay coil passes current, so that the iron core of the electromagnetic relay is magnetized and the contacts are attracted and closed, and the working state of the optocoupler element U4 changes from on to off, and the time at this moment is recorded as t2, and the electromagnetic relay pull-in time is obtained by subtracting t1 from t2; When the optocoupler U2 is disconnected, the power supply of the electromagnetic relay coil is disconnected, and the working state of the optocoupler U3 changes from on to off. At this moment, the relay is disconnected, and the relay disconnection time is recorded as t3; the electromagnetic relay coil does not adsorb the contacts, causing the contacts to be disconnected, and the working state of the optocoupler U4 changes from off to on. The time at this moment is recorded as t4, and the release time of the electromagnetic relay is obtained by subtracting t3 from t4.

Images