Adhesion detection circuit and method suitable for multi-branch parallel relay

Abstract

The invention discloses an adhesion detection circuit and method suitable for a multi-branch parallel relay, and the circuit comprises a first detection circuit which is connected with a first auxiliary contact of the relay; the second detection circuit is used for being connected with a second auxiliary contact of the relay; when the input end of the first detection circuit receives a high level signal, the output end of the first detection circuit outputs a high level to a first auxiliary contact of the relay; when the input end of the second detection circuit receives a high level signal from the second auxiliary contact of the relay, the output end of the second detection circuit outputs a low level signal; when the input end of the first detection circuit receives a low level signal, the output end of the first detection circuit outputs a low level to a first auxiliary contact of the relay; and when the input end of the second detection circuit receives a low level signal from the second auxiliary contact of the relay, the output end of the second detection circuit outputs a high level signal. According to the method, the fault judgment of the parallel relays is high in independence and high in reliability.

Description

Technical Field

[0001] The invention belongs to the technical field of electric vehicles, and in particular relates to a sticking detection circuit and method suitable for multi-branch parallel relays. Background Art

[0002] In the field of electric buses, multiple high-voltage systems are often connected in parallel, which corresponds to the need to control multiple parallel branch positive relays and determine their working status. Relay adhesion detection is one of the basic functions that must be completed during the power-on self-test of the battery pack. The current mainstream relay adhesion detection circuits are as follows: Figure 1 As shown, after the battery management system is powered on, the battery negative electrode ( Figure 1 The BAT- in the figure is the reference voltage point, and the positive electrode of the battery ( Figure 1 The voltage of BAT+ in the circuit is V1, which sends the pre-charge relay and the main positive relay ( Figure 1 Before the B+) relay in the circuit sends a closing command, the voltage values ​​are compared. If V2>98%*V1, at least one of the main positive relay or the pre-charge relay has a sticking fault. Because the pre-charge relay is connected in series with the pre-charge resistor R, the pre-charge resistor R is generally not short-circuited, and the pre-charge relay will not stick. Generally, it is believed that the main positive relay has a sticking fault. However, at the moment of the sticking fault, this solution cannot directly determine which of the main positive relay and the pre-charge relay is sticking, causing the V2 voltage to rise. Summary of the invention

[0003] In view of the above problems, the present invention proposes a sticking detection circuit and method suitable for multi-branch parallel relays, which has high independence and reliability in fault judgment of parallel relays.

[0004] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions: In a first aspect, the present invention provides a sticking detection circuit applicable to a multi-branch parallel relay, comprising: A first detection circuit, used to be connected to a first auxiliary contact of the relay; A second detection circuit is used to be connected to a second auxiliary contact of the relay; When the input end of the first detection circuit receives a high level signal, the output end thereof outputs a high level to the first auxiliary contact of the relay; When the input end of the second detection circuit receives a high level signal from the second auxiliary contact of the relay, the output end thereof outputs a low level signal; When the input end of the first detection circuit receives a low level signal, the output end thereof outputs a low level to the first auxiliary contact of the relay; When the input end of the second detection circuit receives a low level signal from the second auxiliary contact of the relay, the output end thereof outputs a high level signal.

[0005] In the above scheme, the first detection circuit and the second detection circuit are respectively connected to the two auxiliary contacts of the same relay to detect whether a single relay is stuck. This scheme can realize independent detection of multiple relays, and the corresponding multiple branches do not interfere with each other, have strong independence, easy reuse and high reliability.

[0006] In combination with the first aspect, optionally, the first detection circuit includes a first NPN-type triode, a second triode, a third triode, and a fourth PNP-type triode; The bases of the first transistor and the second transistor are connected to form an input end of a first detection circuit, which is used to be connected to a controller to receive a high level signal or a low level signal; The collector of the first transistor is connected to one end of the first resistor, the other end of the first resistor is connected to the base of the third transistor, and the emitter of the first transistor is grounded; The emitter of the third transistor is used to receive a 24V voltage signal, and the collector thereof is connected to one end of a fifth resistor, the other end of the fifth resistor is connected to the cathode of the first diode, and the anode of the first diode is connected to the collector of the fourth transistor, forming an output end of the first detection circuit; The collector of the second transistor is connected to one end of the second resistor and the third resistor respectively, and the other end of the second resistor is connected to a 3.3V voltage signal; the other end of the third resistor is connected to the base of the fourth transistor and one end of the fourth resistor respectively; the emitter of the second transistor is grounded; the other end of the fourth resistor and the emitter of the fourth transistor are both grounded.

[0007] In the above scheme, when the input end of the first detection circuit receives a high level, the first transistor and the second transistor are in the on state at the same time, resulting in the third resistor and the fourth resistor being the bias resistors of the fourth transistor, and the levels at both ends of the third resistor and the fourth resistor being pulled to 0V, so the fourth transistor is in the off state; the third transistor has two bias resistors inside, and the third transistor is configured in a saturated on state through the first resistor, and the 24V voltage passes through the emitter of the third transistor to the collector, and then passes through the fifth resistor and the first and second diodes, and finally outputs a 24V high level to the outside through the output end of the first detection circuit; when the input end of the first detection circuit receives a low level, the first transistor and the second transistor are in the off state at the same time, resulting in the third transistor being in the off state, at this time, the base of the fourth transistor is pulled up by the 3.3V voltage, and is in a fully saturated on state through the third resistor and the fourth resistor, and then is connected to GND, and outputs a 0V low level to the outside through the output end of the first detection circuit.

[0008] In combination with the first aspect, optionally, the first detection circuit further includes a first protection circuit, the first protection circuit includes a second diode, the anode of the second diode is grounded, and the cathode is connected to the output end of the first detection circuit.

[0009] In the above solution, the second diode is used to protect the output end of the first detection circuit. The second diode has a package size of SMA and a rated working voltage of 33V.

[0010] In combination with the first aspect, optionally, the first detection circuit further includes a voltage divider circuit and a first filter circuit; The voltage divider circuit includes a sixth resistor and a seventh resistor; one end of the sixth resistor is connected to the output end of the first detection circuit, and the other end is connected to one end of the seventh resistor, and the other end of the seventh resistor is grounded; The first filtering circuit includes an eighth resistor and a first capacitor, one end of the eighth resistor is connected to the connection point between the sixth resistor and the seventh resistor, and the other end is connected to one end of the first capacitor to form an output voltage detection point, and the other end of the first capacitor is grounded.

[0011] In the above scheme, the output voltage of the first detection circuit is monitored by the sixth resistor and the seventh resistor. When the output voltage detection point continuously outputs a signal, it indicates that the first detection circuit is in a normal state. In the specific implementation process, the output voltage detection point is generally connected to the Oupt1_ADC port of the controller, thereby realizing the ADC recovery function, which can self-check the hardware failure of the adhesion circuit and improve the safety level. And by setting the first filtering circuit, the Oupt1_ADC port of the controller is filtered and protected.

[0012] In combination with the first aspect, optionally, the second detection circuit includes: a fifth NPN transistor and a reverse breakdown diode; The base of the fifth transistor is connected to the cathode of the reverse breakdown diode, the emitter is grounded, one end of the collector is connected to one end of the ninth resistor, and is used as the output end of the second detection circuit; the other end of the ninth resistor is used to connect to the 3V voltage; The anode of the reverse breakdown diode is used as the input terminal of the second detection circuit.

[0013] In the above scheme, when the input end of the second detection circuit receives a high-level signal from the second auxiliary contact of the relay, the fifth transistor is in a conducting state after reverse breakdown of the diode, and the output end of the second detection circuit outputs a low level of 0V to the outside; when the input end of the second detection circuit receives a high-level signal from the second auxiliary contact of the relay, the fifth transistor is in a cut-off state after reverse breakdown of the diode, resulting in the collector and the emitter being unable to conduct, so through the pull-up voltage of the ninth resistor, the output end of the second detection circuit outputs a high level of 3.3V to the outside.

[0014] In combination with the first aspect, optionally, the second detection circuit also includes a second protection circuit, which includes a second capacitor and a third diode; one end of the second capacitor is connected to the positive electrode of the third diode and then to the ground, and the other end is connected to the negative electrode of the third diode and then to the positive electrode of the breakdown diode.

[0015] In the above solution, the second capacitor and the third diode cooperate to protect the input signal received by the second detection circuit. The package size of the third diode is SMA, and the rated working voltage is 33V.

[0016] In combination with the first aspect, optionally, the second detection circuit further includes a second filtering circuit, and the second filtering circuit includes: a tenth resistor and a third capacitor; One end of the tenth resistor is connected to the base of the fifth transistor and one end of the third capacitor respectively, and the other end is connected to the cathode of the reverse breakdown diode; the other end of the third capacitor is connected to the emitter of the fifth transistor.

[0017] In the above solution, the second filtering circuit is used to filter and protect the signal received by the second detection circuit.

[0018] In a second aspect, the present invention provides a detection method based on the adhesion detection circuit described in any one of the first aspects, comprising: Calculating a duty cycle based on the low level signal and the high level signal output by the second detection circuit; When the calculated duty cycle is within the preset duty cycle range, it means that the auxiliary contact of the relay is in a closed state and the main contact of the relay is in an open state, and it is determined that the relay is not sticking; When the calculated duty cycle is outside the preset duty cycle range, it means that the auxiliary contacts of the relay are in an open state and the main contacts of the relay are in a closed state, and the relay is determined to be stuck.

[0019] In the above scheme, the first detection circuit and the second detection circuit are respectively connected to the two auxiliary contacts of the same relay to detect whether a single relay is stuck. This scheme can realize independent detection of multiple relays, and the corresponding multiple branches do not interfere with each other, have strong independence, easy reuse and high reliability.

[0020] Compared with the prior art, the present invention has the following beneficial effects: The present invention utilizes a first detection circuit and a second detection circuit respectively connected to two auxiliary contacts of the same relay to detect whether a single relay is stuck. This solution can realize independent detection of multiple relays, and the corresponding multiple branches do not interfere with each other, have strong independence, easy reuse, and high reliability.

[0021] The present invention has an ADC recovery function, can self-check adhesion circuit hardware failures, and improve the safety level. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor, among which: Figure 1 It is a schematic diagram of a detection circuit in the prior art; Figure 2 A circuit diagram of a first detection circuit according to an embodiment of the present invention; Figure 3 A circuit diagram of a second detection circuit according to an embodiment of the present invention; Figure 4 A schematic diagram of the principle of an adhesion detection circuit according to an embodiment of the present invention; Figure 5 This is the internal structure diagram of a relay with auxiliary contacts. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may also include different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0025] In the description of the present invention, "several" means more than one, "many" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0026] In the description of the present invention, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0027] The application principle of the present invention is described in detail below in conjunction with the accompanying drawings. Example

[0028] In an embodiment of the present invention, a sticking detection circuit suitable for multi-branch parallel relays is provided. Figure 2 and Figure 3 As shown, it includes: a first detection circuit and a second detection circuit; The first detection circuit is used to be connected to the first auxiliary contact of the relay; The second detection circuit is used to be connected to the second auxiliary contact of the relay; When the input end of the first detection circuit receives a high level signal, the output end thereof outputs a high level to the first auxiliary contact of the relay; When the input end of the second detection circuit receives a high level signal from the second auxiliary contact of the relay, the output end thereof outputs a low level signal; When the input end of the first detection circuit receives a low level signal, the output end thereof outputs a low level to the first auxiliary contact of the relay; When the input end of the second detection circuit receives a low level signal from the second auxiliary contact of the relay, the output end thereof outputs a high level signal.

[0029] In the above scheme, the first detection circuit and the second detection circuit are respectively connected to the two auxiliary contacts of the same relay to detect whether a single relay is stuck. This scheme can realize independent detection of multiple relays, and the corresponding multiple branches do not interfere with each other, have strong independence, easy reuse and high reliability.

[0030] In a specific implementation of the embodiment of the present invention, Figure 2 As shown, the first detection circuit includes a first NPN transistor Q6201, a second transistor Q6204, a third transistor Q6200, and a fourth PNP transistor Q6203; the first transistor Q6201, the second transistor Q6204, and the third transistor Q6200 are all provided with bias resistors; The bases of the first transistor Q6201 and the second transistor Q6204 are connected to form the input end of the first detection circuit, which is used to communicate with the controller (i.e. Figure 4 The MCU chip inside the BMS host is connected to receive high-level signals or low-level signals; The collector of the first transistor Q6201 is connected to one end of the first resistor R6226, the other end of the first resistor R6226 is connected to the base of the third transistor Q6200, and the emitter of the first transistor Q6201 is grounded; The emitter of the third transistor Q6200 is used to receive a 24V voltage signal (i.e., a KL30 signal), and the collector thereof is connected to one end of a fifth resistor R6200, the other end of the fifth resistor R6200 is connected to the cathode of a first diode D6200, and the anode of the first diode D6200 is connected to the collector of a fourth transistor Q6203, forming an output end of a first detection circuit; The collector of the second transistor Q6204 is respectively connected to one end of the second resistor R6210 and the third resistor R6211, and the other end of the second resistor R6210 is connected to a 3.3V voltage signal; the other end of the third resistor R6211 is respectively connected to the base of the fourth transistor Q6203 and one end of the fourth resistor R6212; the emitter of the second transistor Q6204 is grounded; the other end of the fourth resistor R6212 and the emitter of the fourth transistor Q6203 are both grounded.

[0031] In the above scheme, when the input terminal of the first detection circuit receives a high level (ie Figure 2 The PWM_OUT_EN1 pin in the circuit receives a high level from the controller), the first transistor Q6201 and the second transistor Q6204 are both in the on state, resulting in the third resistor R6211 (in the specific application process, it can be set to 10KΩ) and the fourth resistor R6212 (in the specific application process, it can be set to 10KΩ) as the bias resistor of the fourth transistor Q6203, and the voltage levels at both ends of the third resistor R6211 and the fourth resistor R6212 are pulled to OV, so the fourth transistor Q6203 is in the off state; the third transistor Q There are two bias resistors inside 6200 (in the specific application process, it can be set to 10KΩ), and then the third transistor Q6200 is configured in a saturated conduction state through the first resistor R6226 (in the specific application process, it can be set to 10KΩ). The 24V voltage passes through the emitter (i.e., pin 2) of the third transistor Q6200 to the collector (i.e., pin 3), and then passes through the fifth resistor R6200 (in the specific application process, it can be set to 10KΩ) and the first diode D6200, and finally outputs a 24V high level through the output end of the first detection circuit (i.e., through Figure 2 PWM_OUT1 in the output 24V high level); when the input end of the first detection circuit receives a low level (i.e. Figure 2 The PWM_OUT_EN1 pin in the circuit receives a low level from the controller), the first transistor Q6201 and the second transistor are both in the off state, causing the third transistor Q6200 to be in the off state. At this time, the base of the fourth transistor Q6203 is pulled up by the 3.3V voltage, and is in a fully saturated on state through the third resistor R6211 and the fourth resistor R6212, and then connected to GND, and outputs a 0V low level to the outside through the output end of the first detection circuit (that is, PWM_OUT1 outputs a 0V low level). In the specific implementation process, the resistance value of the second resistor R6210 can be set to 1kΩ.

[0032] In a specific implementation of the embodiment of the present invention, Figure 2 As shown, the first detection circuit also includes a first protection circuit, and the first protection circuit includes a second diode D6202, the anode of the second diode D6202 is grounded, and the cathode is connected to the output end of the first detection circuit.

[0033] In the above scheme, the second diode D6202 is used to protect the output end of the first detection circuit. The second diode D6202 has a package size of SMA and a rated working voltage of 33V.

[0034] In a specific implementation of the embodiment of the present invention, Figure 2 As shown, the first detection circuit also includes a voltage divider circuit and a first filter circuit; The voltage divider circuit includes a sixth resistor R6204 and a seventh resistor R6206; one end of the sixth resistor R6204 is connected to the output end of the first detection circuit, and the other end is connected to one end of the seventh resistor R6206, and the other end of the seventh resistor R6206 is grounded; The first filter circuit includes an eighth resistor R6205 and a first capacitor C6201, one end of the eighth resistor R6205 is connected to the connection point between the sixth resistor R6204 and the seventh resistor R6206, and the other end is connected to one end of the first capacitor C6201 to form an output voltage detection point, and the other end of the first capacitor C6201 is grounded. In a specific implementation process, the eighth resistor R6205 can be set to 10kΩ, and the first capacitor C6201 is set to 10nF.

[0035] In the above scheme, the output voltage of the first detection circuit is monitored by the sixth resistor R6204 and the seventh resistor R6206. When the output voltage detection point continuously outputs a signal, it indicates that the first detection circuit is in a normal state. In the specific implementation process, the output voltage detection point is generally connected to the Oupt1_ADC port of the controller, and the real-time voltage return of the Oupt1_ADC port is used to monitor whether the output function of the first detection circuit is normal, thereby realizing the ADC recovery function, and the hardware failure of the adhesion circuit can be self-checked to improve the safety level. And by setting the first filtering circuit, the Oupt1_ADC port of the controller is filtered and protected. In the specific application process, the sixth resistor R6204 takes 33kΩ and the seventh resistor R6206 takes 4.7kΩ.

[0036] In a specific implementation of the embodiment of the present invention, Figure 3 As shown, the second detection circuit includes: a fifth transistor Q6202 of NPN type and a reverse breakdown diode Z6200; The base of the fifth transistor Q6202 is connected to the negative electrode of the reverse breakdown diode Z6200, the emitter thereof is grounded, and one end of the collector thereof is connected to one end of the ninth resistor R6207, serving as the output end of the second detection circuit (i.e. Figure 3 Input1_MCU in the figure); the other end of the ninth resistor R6207 is used to access the 3V voltage; The anode of the reverse breakdown diode Z6200 is used as the input terminal of the second detection circuit (i.e. Figure 3 PWMIN1 in the PWM output).

[0037] In the above scheme, when the input end of the second detection circuit receives a high-level signal from the second auxiliary contact of the relay, the fifth transistor Q6202 is in a conducting state after reverse breakdown of the diode, and the output end of the second detection circuit outputs a 0V low level to the MCU chip inside the BMS host; when the input end of the second detection circuit receives a high-level signal from the second auxiliary contact of the relay, the fifth transistor Q6202 is in a cut-off state after reverse breakdown of the diode, resulting in the collector and emitter base of the fifth transistor Q6202 being unable to conduct, so the voltage is pulled up through the pull-up resistor of the ninth resistor R6207, and the output end of the second detection circuit outputs a 3.3V high level. In the specific implementation process, the package of the reverse breakdown diode Z6200 is SOD123, and the rated breakdown voltage is 2V. In the specific implementation process, the resistance value of the ninth resistor R6207 is 10kΩ.

[0038] In a specific implementation of the embodiment of the present invention, Figure 3 As shown, the second detection circuit also includes a second protection circuit, which includes a second capacitor C6203 and a third diode D6201; one end of the second capacitor C6203 is connected to the positive electrode of the third diode D6201 and then grounded, and the other end is connected to the negative electrode of the third diode D6201 and then connected to the positive electrode of the breakdown diode.

[0039] In the above scheme, the second capacitor C6203 and the third diode D6201 are used to protect the input signal received by the second detection circuit. The package size of the third diode D6201 is SMA, and the rated working voltage is 33 V. In the specific implementation process, the second capacitor C6203 can be set to 10nF.

[0040] In a specific implementation of the embodiment of the present invention, Figure 3 As shown, the second detection circuit further includes a second filtering circuit, and the second filtering circuit includes: a tenth resistor R6209 and a third capacitor C6202; One end of the tenth resistor R6209 is respectively connected to the base of the fifth transistor Q6202 and one end of the third capacitor C6202, and the other end is connected to the cathode of the reverse breakdown diode Z6200; the other end of the third capacitor C6202 is connected to the emitter of the fifth transistor Q6202.

[0041] In the above solution, the second filter circuit is used to filter and protect the signal received by the second detection circuit. In a specific implementation, the resistance of the tenth resistor R6209 can be set to 10KΩ, and the third capacitor C6202 can be set to 10nF.

[0042] In the specific implementation process, a relay is connected in series in each branch. Figure 4 As shown, three relays are used as an example for explanation. The three relays are denoted as S1, S2 and S3 respectively. The three relays are connected to the drive lines HSD and KL31 respectively. Among them, HV1, HV2, HV4, HV5 and HV6 are high-voltage detection points. PWM_OUT is used to connect to the output end of the first detection circuit, PWM_IN is used to connect to the input end of the second detection circuit, M1 is the motor load of the whole vehicle, Pre-RES is the pre-charging resistance of the battery pack, shunt is the current sensor of the battery pack, and PACK- is the total negative reference point of the battery pack. There are also three relays for main positive, main negative and pre-charging. Pack1, Pack2 and Pack3 are three electrical measurement packages. Fuse1, Fuse2 and Fuse3 are three fuses in the battery pack. All three relays have auxiliary contacts. The internal structure of the relay is as shown below. Figure 5 The auxiliary contact state is opposite to the actual relay main contact state, that is, the main contact is disconnected and the auxiliary contact is closed, and the main contact is closed and the auxiliary contact is disconnected. The relay is connected in series in the branch, the two main contacts of the relay are respectively connected to the branch, and the two auxiliary contacts of the relay are connected to the adhesion detection circuit proposed in the embodiment of the present invention.

[0043] Based on the low-level signal and the high-level signal output by the second detection circuit, the duty cycle is calculated; when the calculated duty cycle is within the preset duty cycle range (for example, 40%-60%), it means that the auxiliary contact of the relay is in a closed state, the main contact of the relay is in an open state, and the relay is determined to be non-adhesive; when the calculated duty cycle is outside the preset duty cycle range, it means that the auxiliary contact of the relay is in an open state, the main contact of the relay is in a closed state, and the relay is determined to be adhesive. The duty cycle range is set according to actual needs. Example

[0044] An embodiment of the present invention provides a detection method based on the adhesion detection circuit described in any one of Embodiment 1, comprising the following steps: (1) calculating a duty cycle based on a low level signal and a high level signal output by the second detection circuit; (2) When the calculated duty cycle is within the preset duty cycle range, it means that the auxiliary contact of the relay is in a closed state and the main contact of the relay is in an open state, and it is determined that the relay is not sticking; (3) When the calculated duty cycle is outside the preset duty cycle range, it means that the auxiliary contacts of the relay are in the open state and the main contacts of the relay are in the closed state, and the relay is determined to be stuck.

[0045] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the protection content of the present invention.

[0046] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A sticking detection circuit suitable for multi-branch parallel relays, characterized in that: include: A first detection circuit, used to be connected to a first auxiliary contact of the relay; A second detection circuit is used to be connected to a second auxiliary contact of the relay; When the input end of the first detection circuit receives a high level signal, the output end thereof outputs a high level to the first auxiliary contact of the relay; When the input end of the second detection circuit receives a high level signal from the second auxiliary contact of the relay, the output end thereof outputs a low level signal; When the input end of the first detection circuit receives a low level signal, the output end thereof outputs a low level to the first auxiliary contact of the relay; When the input end of the second detection circuit receives a low level signal from the second auxiliary contact of the relay, the output end thereof outputs a high level signal.

2. The adhesion detection circuit applicable to multi-branch parallel relays according to claim 1, characterized in that: The first detection circuit includes a first transistor, a second transistor, a third transistor of NPN type, and a fourth transistor of PNP type; The bases of the first transistor and the second transistor are connected to form an input end of a first detection circuit, which is used to be connected to a controller to receive a high level signal or a low level signal; The collector of the first transistor is connected to one end of the first resistor, the other end of the first resistor is connected to the base of the third transistor, and the emitter of the first transistor is grounded; The emitter of the third transistor is used to receive a 24V voltage signal, and the collector thereof is connected to one end of a fifth resistor, the other end of the fifth resistor is connected to the cathode of the first diode, and the anode of the first diode is connected to the collector of the fourth transistor, forming an output end of the first detection circuit; The collector of the second transistor is connected to one end of the second resistor and the third resistor respectively, and the other end of the second resistor is connected to a 3.3V voltage signal; the other end of the third resistor is connected to the base of the fourth transistor and one end of the fourth resistor respectively; the emitter of the second transistor is grounded; the other end of the fourth resistor and the emitter of the fourth transistor are both grounded.

3. A sticking detection circuit suitable for multi-branch parallel relays according to claim 2, characterized in that: The first detection circuit further includes a first protection circuit. The first protection circuit includes a second diode. The anode of the second diode is grounded, and the cathode of the second diode is connected to the output end of the first detection circuit.

4. A sticking detection circuit suitable for multi-branch parallel relays according to claim 2 or 3, characterized in that: The first detection circuit also includes a voltage divider circuit and a first filter circuit; The voltage divider circuit includes a sixth resistor and a seventh resistor; one end of the sixth resistor is connected to the output end of the first detection circuit, and the other end is connected to one end of the seventh resistor, and the other end of the seventh resistor is grounded; The first filtering circuit includes an eighth resistor and a first capacitor, one end of the eighth resistor is connected to the connection point between the sixth resistor and the seventh resistor, and the other end is connected to one end of the first capacitor to form an output voltage detection point, and the other end of the first capacitor is grounded.

5. A sticking detection circuit suitable for multi-branch parallel relays according to claim 2, characterized in that: When the input end of the first detection circuit receives a high level, the first transistor and the second transistor are in the on state at the same time, resulting in the third resistor and the fourth resistor being bias resistors of the fourth transistor, and the levels at both ends of the third resistor and the fourth resistor being pulled to 0V, so the fourth transistor is in the cut-off state; the third transistor has two bias resistors inside, and the third transistor is configured in a saturated conduction state through the first resistor, and the 24V voltage passes through the emitter to the collector of the third transistor, and then through the fifth resistor and the first diode, and finally outputs a 24V high level to the outside through the output end of the first detection circuit; When the input end of the first detection circuit receives a low level, the first transistor and the second transistor are in the cut-off state at the same time, causing the third transistor to be in the cut-off state. At this time, the base of the fourth transistor is pulled up by the 3.3V voltage, and is in a fully saturated conduction state through the third resistor and the fourth resistor, directly connected to the ground, and outputs a 0V low level to the outside through the output end of the first detection circuit.

6. A sticking detection circuit suitable for multi-branch parallel relays according to claim 1, characterized in that: The second detection circuit includes: a fifth transistor of NPN type and a reverse breakdown diode; The base of the fifth transistor is connected to the cathode of the reverse breakdown diode, the emitter is grounded, one end of the collector is connected to one end of the ninth resistor, and is used as the output end of the second detection circuit; the other end of the ninth resistor is used to connect to the 3V voltage; The anode of the reverse breakdown diode is used as the input terminal of the second detection circuit.

7. The adhesion detection circuit applicable to multi-branch parallel relays according to claim 5, characterized in that: The second detection circuit also includes a second protection circuit, which includes a second capacitor and a third diode; one end of the second capacitor is connected to the anode of the third diode and then to ground, and the other end is connected to the cathode of the third diode and then to the anode of the breakdown diode.

8. A sticking detection circuit suitable for multi-branch parallel relays according to claim 5 or 6, characterized in that: The second detection circuit further includes a second filtering circuit, and the second filtering circuit includes: a tenth resistor and a third capacitor; One end of the tenth resistor is connected to the base of the fifth transistor and one end of the third capacitor respectively, and the other end is connected to the cathode of the reverse breakdown diode; the other end of the third capacitor is connected to the emitter of the fifth transistor.

9. The adhesion detection circuit applicable to multi-branch parallel relays according to claim 1, characterized in that: When the input end of the second detection circuit receives a high level signal from the second auxiliary contact of the relay, the fifth transistor is turned on after reverse breakdown of the diode, and the output end of the second detection circuit outputs a low level of 0V to the outside; When the input end of the second detection circuit receives a high-level signal from the second auxiliary contact of the relay, the fifth transistor is in a cut-off state after reverse breakdown of the diode, causing the collector and the emitter to be unable to conduct, so through the pull-up voltage of the ninth resistor, the output end of the second detection circuit outputs a high level of 3.3V.

10. A detection method based on the adhesion detection circuit according to any one of claims 1 to 9, characterized in that: include: Calculating a duty cycle based on the low level signal and the high level signal output by the second detection circuit; When the calculated duty cycle is within the preset duty cycle range, it means that the auxiliary contact of the relay is in a closed state and the main contact of the relay is in an open state, and it is determined that the relay is not sticking; When the calculated duty cycle is outside the preset duty cycle range, it means that the auxiliary contacts of the relay are in an open state and the main contacts of the relay are in a closed state, and the relay is determined to be stuck.

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