Input positive and negative terminal contactor fault self-detection circuit and self-detection method

Abstract

The present invention discloses an input positive and negative terminal contactor fault self-checking circuit and a self-checking method, including an input positive terminal contactor fault detection circuit, an input negative terminal contactor fault detection circuit and a main control circuit, wherein the input positive terminal contactor fault detection circuit is used to detect the contactor fault of the input positive terminal, the input negative terminal contactor fault detection circuit is used to detect the contactor fault of the input negative terminal, the main control circuit is connected to the input positive terminal contactor fault detection circuit and the input negative terminal contactor fault detection circuit, and the main control circuit is used to send out an output control signal and receive a detection signal to judge the contactor fault of the input positive terminal contactor fault detection circuit and the input negative terminal contactor fault detection circuit to control the closing and opening of the contactor. The present invention has the advantages of being able to detect the input positive and negative terminals, being efficient and reliable, being safe in application, and being able to save space.

Description

Technical Field

[0001] The invention belongs to the technical field of contactor fault detection, and in particular relates to a fault self-detection circuit and a self-detection method for a positive and negative input contactor. Background Art

[0002] In high-voltage and high-current equipment using contactors, it is usually desirable to perform a contactor fault self-check before powering on to ensure application safety. If the contactor is only located at the positive input terminal, voltage sampling can be added after the contactor at the positive input terminal, and then the collected voltage signal can be used to determine whether the contactor has a fault. This contactor fault self-check method is called a high-voltage detection method. For details, please refer to Figure 2 This is a circuit diagram of a high-voltage detection method. However, this high-voltage detection method requires the use of many large package resistors in series for voltage sampling, which increases the layout space of the PCB board. What's more, this detection method requires the introduction of high voltage to detect whether the contactor is faulty, thereby causing a high-voltage safety hazard during system self-test. The faults of the contactor mainly include contactor adhesion and inability to close. If the contactor fault detection adopts a high-voltage detection method, when the contactor has a adhesion fault, the high voltage will be directly transmitted to the back end, causing a safety risk. When the contactor cannot be closed, the contactor cannot work normally. Summary of the invention

[0003] In order to solve the deficiencies in the prior art, the present invention provides an input positive and negative terminal contactor fault self-detection circuit and self-detection method which can detect the input positive and negative terminals and is efficient, reliable and safe to use.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] Input positive and negative terminal contactor fault self-detection circuit, including:

[0006] Input positive terminal contactor fault detection circuit, used to detect the contactor fault at the input positive terminal;

[0007] An input negative terminal contactor fault detection circuit, used to detect a contactor fault at the input negative terminal; and

[0008] The main control circuit is connected to the input positive contactor fault detection circuit and the input negative contactor fault detection circuit. The main control circuit is used to send out the output control signal and receive the detection signal to determine the contactor fault of the input positive contactor fault detection circuit and the input negative contactor fault detection circuit to control the closing and opening of the contactor, wherein:

[0009] The input positive terminal contactor fault detection circuit includes an input auxiliary source Vdd, a first sampling protection circuit and a first contactor K1 which are connected in series in sequence. The main control circuit is connected to the first sampling protection circuit. The main control circuit is used to receive signals from the first sampling protection circuit and issue a closing and opening state command of the first contactor K1.

[0010] The input negative terminal contactor fault detection circuit includes an input auxiliary source Vcc, a second sampling protection circuit and a second contactor K2 connected in series in sequence. The main control circuit is connected to the second sampling protection circuit. The main control circuit is used to receive signals from the second sampling protection circuit and issue closing and opening state commands for the second contactor K2.

[0011] Preferably, the first sampling protection circuit includes a first diode D1, a first resistor R1, a second resistor R2, a first capacitor C1 and a first isolation operational amplifier U1, an anode end of the first diode D1 is connected to the Vdd end of the input auxiliary source Vdd, a cathode end of the first diode D1 is connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to one end of the second resistor R2, the other end of the second resistor R2 is connected to one end of the first contactor K1, the other end of the first contactor K1 is connected to the reference ground Vin+ end of the input auxiliary source Vdd, the first capacitor C1 is connected in parallel with the second resistor R2, and the non-inverting input end of the first isolation operational amplifier U1 is connected to the first resistor R1 is connected to the connection point of the second resistor R2, and a current limiting resistor Ra is provided between the non-inverting input terminal of the first isolation operational amplifier U1 and the connection point of the first resistor R1 and the second resistor R2, the inverting input terminal of the first isolation operational amplifier U1 is connected to the connection point of the first contactor K1 and the second resistor R2, the Vdd1 terminal of the first isolation operational amplifier U1 is connected to the Vdd terminal of the input auxiliary source Vdd, the GND terminal of the first isolation operational amplifier U1 is connected to the reference ground Vin+ terminal of the input auxiliary source Vdd, the AGND terminal of the first isolation operational amplifier U1 is connected to the GND terminal of the main control circuit, and the output terminal of the first isolation operational amplifier U1 is connected to the IO port of the main control circuit.

[0012] Preferably, the second sampling protection circuit includes a second diode D2, a third resistor R3, a fourth resistor R4, a second capacitor C2 and a second isolation operational amplifier U2, an anode end of the second diode D2 is connected to the Vcc end of the input auxiliary source Vcc, a cathode end of the second diode D2 is connected to one end of the third resistor R3, the other end of the third resistor R3 is connected to one end of the fourth resistor R4, the other end of the fourth resistor R4 is connected to one end of the second contactor K2, the other end of the second contactor K2 is connected to the reference ground Vin-end of the input auxiliary source Vcc, the second capacitor C2 is connected in parallel with the fourth resistor R4, and the in-phase input end of the second isolation operational amplifier U2 is connected to the third resistor R3. R3 and the connection point of the fourth resistor R4 are connected, and a current limiting resistor Rb is provided between the in-phase input terminal of the second isolation operational amplifier U2 and the connection point of the third resistor R3 and the fourth resistor R4, the inverting input terminal of the second isolation operational amplifier U2 is connected to the connection point of the second contactor K2 and the fourth resistor R4, the Vdd1 terminal of the second isolation operational amplifier U2 is connected to the Vcc terminal of the input auxiliary source Vcc, the GND terminal of the second isolation operational amplifier U2 is connected to the reference ground Vin-terminal of the input auxiliary source Vcc, the AGND terminal of the second isolation operational amplifier U2 is connected to the GND terminal of the main control circuit, and the output terminal of the second isolation operational amplifier U2 is connected to the IO port of the main control circuit.

[0013] Preferably, the forward conduction voltage drops of the first diode D1 and the second diode D2 are both Vf, the amplification factor of the first isolation operational amplifier U1 is Kv1, the amplification factor of the second isolation operational amplifier U2 is Kv2, the resistance value of the first resistor R1 is much larger than the resistance value of the second resistor R2, the resistance value of the third resistor R3 is much larger than the resistance value of the fourth resistor R4, and the main control circuit is a circuit including a controller MCU or DSP.

[0014] The present invention also discloses a self-checking method for the above-mentioned input positive and negative terminal contactor fault self-checking circuit, comprising the following steps:

[0015] S1, define the end of the first contactor K1 connected to the reference ground Vin+ of the input auxiliary source Vdd as the input end of the first contactor K1, and define the other end of the first contactor K1 as the output end of the first contactor K1, define the end of the second contactor K2 connected to the reference ground Vin- of the input auxiliary source Vcc as the output end of the second contactor K2, and define the other end of the second contactor K2 as the input end of the second contactor K2, and then make the output end of the first contactor K1 connected to one end of the first capacitor C1 and the second resistor R2 respectively, and the input end of the second contactor K2 The ends are respectively connected to one end of the second capacitor C2 and the fourth resistor R4, then the output end of the first contactor K1 is connected to the inverting input end of the first isolation operational amplifier U1 and the input end of the first contactor K1 is connected to the reference ground Vin+ end of the input auxiliary source Vdd, then the output end of the second contactor K2 is connected to the reference ground Vin- end of the input auxiliary source Vcc and the input end of the second contactor K2 is connected to the inverting input end of the second isolation operational amplifier U2, and finally an input positive end contactor fault detection circuit and an input negative end contactor fault detection circuit are formed;

[0016] S2, first contactor K1 adhesion fault detection: when the controller MCU or DSP does not send a closing signal for the first contactor K1, the voltage of the second resistor R2 is detected. When the voltage of the second resistor R2 is 0V and the first isolation operational amplifier U1 outputs a 0V signal, the controller MCU or DSP detects the 0V level signal. At this time, the first contactor K1 does not have an adhesion fault. When the voltage of the second resistor R2 is And the output of the first isolation operational amplifier U1 is When the controller MCU or DSP detects the signal The level signal indicates that the first contactor K1 has a sticking fault;

[0017] S3, the first contactor K1 can not close the fault detection: the controller MCU or DSP sends a closing signal of the first contactor K1 and performs a voltage detection of the second resistor R2. When the output of the first isolation operational amplifier U1 is The controller MCU or DSP detects the signal When the voltage of the second resistor R2 is 0V, the first isolation operational amplifier U1 outputs a 0V signal, and the controller MCU or DSP detects a 0V level signal. At this time, the first contactor K1 fails and cannot be closed;

[0018] S4, second contactor K2 adhesion fault detection: when the controller MCU or DSP does not send a closing signal for the second contactor K2, the voltage of the fourth resistor R4 is detected. When the voltage of the fourth resistor R4 is 0V and the second isolation operational amplifier U2 outputs a 0V signal, the controller MCU or DSP detects a 0V level signal. At this time, the second contactor K2 does not have an adhesion fault. When the voltage of the fourth resistor R4 is And the output of the second isolation operational amplifier U2 is When the controller MCU or DSP detects the signal The level signal indicates that the second contactor K2 has a sticking fault;

[0019] S5, the second contactor K2 cannot close the fault detection: the controller MCU or DSP sends a closing signal of the second contactor K2 and performs a voltage detection of the fourth resistor R4. When the output of the second isolation operational amplifier U2 is The controller MCU or DSP detects the signal When the voltage of the fourth resistor R4 is 0V, the second isolation operational amplifier U2 outputs a 0V signal, the controller MCU or DSP detects a 0V level signal, and the second contactor K2 cannot be closed.

[0020] By adopting the above technical solution, the present invention has the following beneficial effects:

[0021] (1) Compared with the prior art, the present invention saves a plurality of large package resistors, can save space on the PCB board, and reduce the size of the PCB board;

[0022] (2) The present invention uses the input auxiliary source Vdd, the first sampling protection circuit, the input auxiliary source Vcc and the second sampling protection circuit to perform fault self-detection on the first contactor K1 and the second contactor K2, without using the high-voltage detection method in the prior art and without using high voltage to detect the contactor, making the detection safer and more reliable;

[0023] (3) The present invention is provided with both an input positive terminal contactor fault detection circuit and an input negative terminal contactor fault detection circuit, which can detect the detector faults at the input positive terminal and the input negative terminal, which is efficient and reliable;

[0024] In summary, the present invention has the advantages of being able to detect the positive and negative input terminals, being efficient and reliable, being safe in application, and being able to save space. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the structure of the present invention;

[0026] Figure 2 The invention is a circuit diagram of a high voltage detection method of a contactor in the prior art. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0028] The components of the embodiments of the present invention generally described and shown in the drawings herein may be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention.

[0029] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0030] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying 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 limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] Example 1

[0033] In this embodiment, a self-test circuit and a self-test method are provided for simultaneously performing fault detection on the contactors at the positive input terminal and the negative input terminal, thereby ensuring application safety, high efficiency and reliability, and saving space. Figure 2As shown, it is a circuit diagram of a high-voltage detection method in the prior art. This method is only applicable to the contactor at the positive input end for detection and requires the introduction of high voltage for fault detection, which poses a high-voltage safety hazard. Moreover, this method is only applicable to the positive input end and is not applicable to the contactor at the negative input end for detection.

[0034] like Figure 1 As shown, in one embodiment of the present invention, the input positive and negative terminal contactor fault self-detection circuit of the present invention includes an input positive terminal contactor fault detection circuit, an input negative terminal contactor fault detection circuit and a main control circuit, the input positive terminal contactor fault detection circuit is used to detect the contactor fault of the input positive terminal, and the input negative terminal contactor fault detection circuit is used to detect the contactor fault of the input negative terminal. It can be understood that in specific applications, the input positive terminal contactor fault detection circuit and the input negative terminal contactor fault detection circuit can be provided with auxiliary sources by the same transformer T1, and the transformer T1 can generate two mutually isolated auxiliary source circuits for the present invention so as to be used for the contactor The main control circuit of the present invention is connected to the input positive contactor fault detection circuit and / or the input negative contactor fault detection circuit respectively for use, and the main control circuit is used to send out the output control signal and receive the detection signal to judge the contactor fault of the input positive contactor fault detection circuit and the input negative contactor fault detection circuit to control the closing and opening of the contactor. In the present invention, the main control circuit is mainly a controller MCU / DSP. More specifically, the main control circuit is a circuit including a controller MCU or DSP;

[0035] Specifically, the input positive end contactor fault detection circuit includes an input auxiliary source Vdd, a first sampling protection circuit and a first contactor K1 connected in series in sequence, the main control circuit is connected to the first sampling protection circuit, the main control circuit is used to receive signals from the first sampling protection circuit and issue a closing and opening state command for the first contactor K1, the first contactor K1 is a contactor located at the input positive end, and the first sampling protection circuit is used to sample the first contactor K1. Similarly, the input negative end contactor fault detection circuit includes an input auxiliary source Vcc, a second sampling protection circuit and a second contactor K2 connected in series in sequence, the main control circuit is connected to the second sampling protection circuit, the main control circuit is used to receive signals from the second sampling protection circuit and issue a closing and opening state command for the second contactor K2, the second contactor K2 is a contactor located at the input negative end, and the second sampling protection circuit is used to sample the second contactor K2.

[0036] Please continue to refer to Figure 1, the two ends of the input auxiliary source Vdd are respectively the Vdd end and the reference ground Vin+ end, the input auxiliary source Vdd occupies a winding of the transformer T1, the first sampling protection circuit includes a first diode D1, a first resistor R1, a second resistor R2, a first capacitor C1 and a first isolation operational amplifier U1, the forward conduction voltage drop of the first diode D1 is Vf, the amplification factor of the first isolation operational amplifier U1 is Kv1, the anode end of the first diode D1 is connected to the Vdd end of the input auxiliary source Vdd, the cathode end of the first diode D1 is connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to one end of the second resistor R2, the other end of the second resistor R2 is connected to one end of the first contactor K1, the other end of the first contactor K1 is connected to the reference ground Vin+ end of the input auxiliary source Vdd, the first The capacitor C1 is connected in parallel with the second resistor R2, the in-phase input terminal of the first isolation operational amplifier U1 is connected to the connection point of the first resistor R1 and the second resistor R2, and a current limiting resistor Ra is provided between the in-phase input terminal of the first isolation operational amplifier U1 and the connection point of the first resistor R1 and the second resistor R2, and the current limiting resistor Ra mainly plays a role of current limiting, the inverting input terminal of the first isolation operational amplifier U1 is connected to the connection point of the first contactor K1 and the second resistor R2, the Vdd1 terminal of the first isolation operational amplifier U1 is connected to the Vdd terminal of the input auxiliary source Vdd, the GND terminal of the first isolation operational amplifier U1 is connected to the reference ground Vin+ terminal of the input auxiliary source Vdd, the AGND terminal of the first isolation operational amplifier U1 is connected to the GND terminal of the main control circuit, and the output terminal of the first isolation operational amplifier U1 is connected to the IO port of the main control circuit;

[0037] It can be understood that the first isolation operational amplifier U1 of the present invention can cooperate with the main control circuit, that is, cooperate with the controller MCU or DSP to realize the fault self-detection of the contactor through the detection of specific resistance voltage, specifically Figure 1 The Vdd1 terminal of the first isolation operational amplifier U1 is connected to the Vdd terminal of the input auxiliary source Vdd, the Vdd2 terminal of the first isolation operational amplifier U1 is the power supply terminal on the isolated output side, the Vout terminal of the first isolation operational amplifier U1 is connected to the IO port of the main control circuit, the Vout terminal of the first isolation operational amplifier U1 is also the output terminal of the first isolation operational amplifier U1, the V- terminal of the first isolation operational amplifier U1 is also the inverting input terminal of the first isolation operational amplifier U1, the V+ terminal of the first isolation operational amplifier U1 is also the non-inverting input terminal of the first isolation operational amplifier U1, the GND terminal of the first isolation operational amplifier U1 is specifically connected to the reference ground Vin+ terminal of the input auxiliary source Vdd, the AGND terminal of the first isolation operational amplifier U1 is specifically connected to the GND terminal of the main control circuit, that is, connected to the GND terminal of the controller MCU / DSP, the main control circuit has multiple IO ports, specifically to Figure 1In the embodiment, the Vout terminal of the first isolation operational amplifier U1 is specifically connected to the IO port of the main control circuit (ie, the controller MCU / DSP).

[0038] Similarly, please continue to refer to Figure 1 , the two ends of the input auxiliary source Vcc are respectively the Vcc end and the reference ground Vin-end, the input auxiliary source Vcc also occupies a winding of the transformer T1, the second sampling protection circuit includes a second diode D2, a third resistor R3, a fourth resistor R4, a second capacitor C2 and a second isolation operational amplifier U2, the forward conduction voltage drop of the second diode D2 is Vf, the amplification factor of the second isolation operational amplifier U2 is Kv2, the anode end of the second diode D2 is connected to the Vcc end of the input auxiliary source Vcc, the cathode end of the second diode D2 is connected to one end of the third resistor R3, the other end of the third resistor R3 is connected to one end of the fourth resistor R4, the other end of the fourth resistor R4 is connected to one end of the second contactor K2, the other end of the second contactor K2 is connected to the reference ground Vin-end of the input auxiliary source Vcc, the second capacitor C2 is connected in parallel with the fourth resistor R4, the in-phase input end of the second isolation operational amplifier U2 is connected to the third resistor R3 and the fourth resistor R4 is connected and a current limiting resistor Rb is provided between the in-phase input terminal of the second isolation operational amplifier U2 and the connection between the third resistor R3 and the fourth resistor R4. The current limiting resistor Rb mainly plays a role of current limiting. The inverting input terminal of the second isolation operational amplifier U2 is connected to the connection between the second contactor K2 and the fourth resistor R4. The Vdd1 terminal of the second isolation operational amplifier U2 is connected to the Vcc terminal of the input auxiliary source Vcc. The GND terminal of the second isolation operational amplifier U2 is connected to the reference ground Vin-terminal of the input auxiliary source Vcc. The AGND terminal of the second isolation operational amplifier U2 is connected to the GND terminal of the main control circuit. The output terminal of the second isolation operational amplifier U2 is connected to the IO port of the main control circuit. In order to accurately judge the fault of the first contactor K1 and the second contactor K2, a more obvious fault threshold is set. The resistance value of the first resistor R1 is much greater than the resistance value of the second resistor R2, and the resistance value of the third resistor R3 is much greater than the resistance value of the fourth resistor R4.

[0039] It is understandable that the second isolation operational amplifier U2 of the present invention can cooperate with the main control circuit, that is, cooperate with the controller MCU or DSP to realize the fault self-detection of the contactor through the detection of the specific resistance voltage. Figure 1The Vdd1 terminal of the second isolation operational amplifier U2 is connected to the Vcc terminal of the input auxiliary source Vcc, the Vdd2 terminal of the second isolation operational amplifier U2 is the power supply terminal on the isolated output side, the Vout terminal of the second isolation operational amplifier U2 is connected to the IO port of the main control circuit, the Vout terminal of the second isolation operational amplifier U2 is also the output terminal of the second isolation operational amplifier U2, the V- terminal of the second isolation operational amplifier U2 is also the inverting input terminal of the second isolation operational amplifier U2, the V+ terminal of the second isolation operational amplifier U2 is also the non-inverting input terminal of the second isolation operational amplifier U2, the AGND terminal of the second isolation operational amplifier U2 is specifically connected to the GND terminal of the main control circuit, that is, connected to the GND terminal of the controller MCU / DSP, and the Vout terminal of the second isolation operational amplifier U2 is specifically connected to the IO port of the main control circuit (that is, the controller MCU / DSP).

[0040] Please continue to refer to Figure 1 , in order to show the continuity of the circuit diagram, Figure 1 The load resistance in R_Load For load application of subsequent stage connected circuit.

[0041] In this embodiment, this embodiment also discloses a self-test method of the above-mentioned input positive and negative terminal contactor fault self-test circuit. In the self-test method of the input positive and negative terminal contactor fault self-test circuit of this embodiment, the contactors located at the input positive terminal and the input negative terminal are mainly tested for two main faults, namely, adhesion fault detection and failure to close fault. Specifically, the following steps are included:

[0042] S1, define the end of the first contactor K1 connected to the reference ground Vin+ of the input auxiliary source Vdd as the input end of the first contactor K1, and define the other end of the first contactor K1 as the output end of the first contactor K1, define the end of the second contactor K2 connected to the reference ground Vin- of the input auxiliary source Vcc as the output end of the second contactor K2, and define the other end of the second contactor K2 as the input end of the second contactor K2, and then make the output end of the first contactor K1 connected to one end of the first capacitor C1 and the second resistor R2 respectively, and the input end of the second contactor K2 The ends are respectively connected to one end of the second capacitor C2 and the fourth resistor R4, then the output end of the first contactor K1 is connected to the inverting input end of the first isolation operational amplifier U1 and the input end of the first contactor K1 is connected to the reference ground Vin+ end of the input auxiliary source Vdd, then the output end of the second contactor K2 is connected to the reference ground Vin- end of the input auxiliary source Vcc and the input end of the second contactor K2 is connected to the inverting input end of the second isolation operational amplifier U2, and finally an input positive end contactor fault detection circuit and an input negative end contactor fault detection circuit are formed;

[0043] The self-checking method of the input positive and negative terminal contactor fault self-checking circuit of the present invention does not need to connect high voltage to the input positive terminal and the input negative terminal, and implements the fault self-checking of the first contactor K1 by sampling the sampling resistor (second resistor R2) at the input end of the first isolation operational amplifier U1 and transmitting it to the controller MCU / DSP, and implements the fault self-checking of the second contactor K2 by sampling the sampling resistor (fourth resistor R4) at the input end of the second isolation operational amplifier U2 and transmitting it to the controller MCU / DSP;

[0044] Specifically, the present embodiment includes four detections: first contactor K1 adhesion fault detection, first contactor K1 unable to close fault detection, second contactor K2 adhesion fault detection, and second contactor K2 unable to close fault detection. More specifically, the following steps are performed:

[0045] S2, first contactor K1 adhesion fault detection: when the controller MCU or DSP does not send a closing signal for the first contactor K1, the voltage of the second resistor R2 is detected. When the voltage of the second resistor R2 is 0V and the first isolation operational amplifier U1 outputs a 0V signal, the controller MCU or DSP detects the 0V level signal. At this time, the first contactor K1 does not have an adhesion fault. When the voltage of the second resistor R2 is And the output of the first isolation operational amplifier U1 is When the controller MCU or DSP detects the signal The first contactor K1 has a sticking fault. In this step, if the first contactor K1 is normally disconnected, the positive input contactor fault detection circuit is disconnected, the voltage across the second resistor R2 is 0V, and the output signal of the first isolation operational amplifier U1 is 0V. The controller MCU / DSP detects the level signal, proving that the first contactor K1 has no sticking fault. If the voltage across the second resistor R2 is The output signal of the first isolation operational amplifier U1 is If the controller MCU / DSP detects this level signal, it proves that the first contactor K1 has a sticking fault;

[0046] S3, the first contactor K1 can not close the fault detection: the controller MCU or DSP sends a closing signal of the first contactor K1 and performs a voltage detection of the second resistor R2. When the output of the first isolation operational amplifier U1 is The controller MCU or DSP detects the signal The first contactor K1 is normally closed at this time. When the voltage of the second resistor R2 is 0V, the first isolation operational amplifier U1 outputs a 0V signal. The controller MCU or DSP detects a 0V level signal. At this time, the first contactor K1 fails and the first contactor K1 cannot be closed. In this step, the controller MCU / DSP first sends a closing signal of the first contactor K1. If the first contactor K1 is normally closed, the input positive terminal contactor fault detection circuit is connected, and the voltage across the second resistor R2 is The output signal of the first isolation operational amplifier U1 is The controller MCU / DSP detects the level signal, which proves that the first contactor K1 is normal. If the voltage across the second resistor R2 is 0V, the output signal of the first isolation operational amplifier U1 is 0V, and the controller MCU / DSP detects the level signal, which proves that the first contactor K1 is faulty and cannot be closed;

[0047] S4, second contactor K2 adhesion fault detection: when the controller MCU or DSP does not send a closing signal for the second contactor K2, the voltage of the fourth resistor R4 is detected. When the voltage of the fourth resistor R4 is 0V and the second isolation operational amplifier U2 outputs a 0V signal, the controller MCU or DSP detects a 0V level signal. At this time, the second contactor K2 does not have an adhesion fault. When the voltage of the fourth resistor R4 is And the output of the second isolation operational amplifier U2 is When the controller MCU or DSP detects the signal The second contactor K2 has a sticking fault. In this step, if the second contactor K2 is normally disconnected, the input negative contactor fault detection circuit is disconnected, the voltage across the fourth resistor R4 is 0V, and the second isolation operational amplifier U2 outputs a 0V signal. The controller MCU / DSP detects the level signal, proving that the second contactor K2 has no sticking fault. If the voltage across the fourth resistor R4 is The output signal of the second isolation operational amplifier U2 is The controller MCU / DSP detects the voltage signal, proving that the second contactor K2 has a sticking fault;

[0048] S5, the second contactor K2 cannot close the fault detection: the controller MCU or DSP sends a closing signal of the second contactor K2 and performs a voltage detection of the fourth resistor R4. When the output of the second isolation operational amplifier U2 is The controller MCU or DSP detects the signal The second contactor K2 is normally closed at this time. When the voltage of the fourth resistor R4 is 0V, the second isolation operational amplifier U2 outputs a 0V signal. The controller MCU or DSP detects the 0V level signal, and the second contactor K2 cannot be closed. In this step, the controller MCU / DSP first sends a closing signal of the second contactor K2. If the second contactor K2 is normally closed, the input negative terminal contactor fault detection circuit is connected, and the voltage across the fourth resistor R4 is The output signal of the second isolation operational amplifier U2 is The controller MCU / DSP detects the voltage signal, proving that the second contactor K2 is normal. If the voltage across the fourth resistor R4 is 0V, the output signal of the second isolation operational amplifier U2 is 0V, and the controller MCU / DSP detects the voltage signal, proving that the second contactor K2 is faulty and cannot be closed.

[0049] This embodiment does not impose any formal limitation on the shape, material, structure, etc. of the present invention. Any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. Input positive and negative terminal contactor fault self-detection circuit, characterized in that: include: Input positive terminal contactor fault detection circuit, used to detect the contactor fault at the input positive terminal; Input negative terminal contactor fault detection circuit, used to detect the contactor fault at the input negative terminal; as well as The main control circuit is connected to the input positive contactor fault detection circuit and the input negative contactor fault detection circuit. The main control circuit is used to send out the output control signal and receive the detection signal to determine the contactor fault of the input positive contactor fault detection circuit and the input negative contactor fault detection circuit to control the closing and opening of the contactor, wherein: The input positive terminal contactor fault detection circuit includes an input auxiliary source Vdd, a first sampling protection circuit and a first contactor K1 which are connected in series in sequence. The main control circuit is connected to the first sampling protection circuit. The main control circuit is used to receive signals from the first sampling protection circuit and issue a closing and opening state command of the first contactor K1. The input negative terminal contactor fault detection circuit includes an input auxiliary source Vcc, a second sampling protection circuit and a second contactor K2 connected in series in sequence, and the main control circuit is connected to the second sampling protection circuit. The main control circuit is used to receive signals from the second sampling protection circuit and issue a closing and opening state command for the second contactor K2; The first sampling protection circuit includes a first diode D1, a first resistor R1, a second resistor R2, a first capacitor C1 and a first isolation operational amplifier U1, wherein an anode end of the first diode D1 is connected to the Vdd end of the input auxiliary source Vdd, a cathode end of the first diode D1 is connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to one end of the second resistor R2, the other end of the second resistor R2 is connected to one end of the first contactor K1, the other end of the first contactor K1 is connected to the reference ground Vin+ end of the input auxiliary source Vdd, the first capacitor C1 is connected in parallel with the second resistor R2, and the non-inverting input end of the first isolation operational amplifier U1 is connected to the first resistor R1. A current limiting resistor Ra is provided between the in-phase input terminal of the first isolation operational amplifier U1 and the connection point of the first resistor R1 and the second resistor R2, the inverting input terminal of the first isolation operational amplifier U1 is connected to the connection point of the first contactor K1 and the second resistor R2, the Vdd1 terminal of the first isolation operational amplifier U1 is connected to the Vdd terminal of the input auxiliary source Vdd, the GND terminal of the first isolation operational amplifier U1 is connected to the reference ground Vin+ terminal of the input auxiliary source Vdd, the AGND terminal of the first isolation operational amplifier U1 is connected to the GND terminal of the main control circuit, and the output terminal of the first isolation operational amplifier U1 is connected to the IO port of the main control circuit; The second sampling protection circuit includes a second diode D2, a third resistor R3, a fourth resistor R4, a second capacitor C2 and a second isolation operational amplifier U2, wherein an anode end of the second diode D2 is connected to the Vcc end of the input auxiliary source Vcc, a cathode end of the second diode D2 is connected to one end of the third resistor R3, the other end of the third resistor R3 is connected to one end of the fourth resistor R4, the other end of the fourth resistor R4 is connected to one end of the second contactor K2, the other end of the second contactor K2 is connected to the reference ground Vin-end of the input auxiliary source Vcc, the second capacitor C2 is connected in parallel with the fourth resistor R4, and the non-inverting input end of the second isolation operational amplifier U2 is connected to the third resistor R3. A current limiting resistor Rb is provided between the in-phase input terminal of the second isolation operational amplifier U2 and the connection between the third resistor R3 and the fourth resistor R4, the inverting input terminal of the second isolation operational amplifier U2 is connected to the connection between the second contactor K2 and the fourth resistor R4, the Vdd1 terminal of the second isolation operational amplifier U2 is connected to the Vcc terminal of the input auxiliary source Vcc, the GND terminal of the second isolation operational amplifier U2 is connected to the reference ground Vin-terminal of the input auxiliary source Vcc, the AGND terminal of the second isolation operational amplifier U2 is connected to the GND terminal of the main control circuit, and the output terminal of the second isolation operational amplifier U2 is connected to the IO port of the main control circuit.

2. The input positive and negative terminal contactor fault self-detection circuit according to claim 1, characterized in that: The forward conduction voltage drops of the first diode D1 and the second diode D2 are both Vf, the amplification factor of the first isolation operational amplifier U1 is Kv1, the amplification factor of the second isolation operational amplifier U2 is Kv2, the resistance value of the first resistor R1 is much larger than the resistance value of the second resistor R2, the resistance value of the third resistor R3 is much larger than the resistance value of the fourth resistor R4, and the main control circuit is a circuit including a controller MCU or DSP.

3. The self-test method of the input positive and negative terminal contactor fault self-test circuit according to claim 2, characterized in that: The following steps are involved: S1, define the end of the first contactor K1 connected to the reference ground Vin+ of the input auxiliary source Vdd as the input end of the first contactor K1, and define the other end of the first contactor K1 as the output end of the first contactor K1, define the end of the second contactor K2 connected to the reference ground Vin- of the input auxiliary source Vcc as the output end of the second contactor K2, and define the other end of the second contactor K2 as the input end of the second contactor K2, and then make the output end of the first contactor K1 connected to one end of the first capacitor C1 and the second resistor R2 respectively, and the input end of the second contactor K2 The ends are respectively connected to one end of the second capacitor C2 and the fourth resistor R4, then the output end of the first contactor K1 is connected to the inverting input end of the first isolation operational amplifier U1 and the input end of the first contactor K1 is connected to the reference ground Vin+ end of the input auxiliary source Vdd, then the output end of the second contactor K2 is connected to the reference ground Vin- end of the input auxiliary source Vcc and the input end of the second contactor K2 is connected to the inverting input end of the second isolation operational amplifier U2, and finally an input positive end contactor fault detection circuit and an input negative end contactor fault detection circuit are formed; S2, first contactor K1 adhesion fault detection: when the controller MCU or DSP does not send a closing signal for the first contactor K1, the voltage of the second resistor R2 is detected. When the voltage of the second resistor R2 is 0V and the first isolation operational amplifier U1 outputs a 0V signal, the controller MCU or DSP detects the 0V level signal. At this time, the first contactor K1 does not have an adhesion fault. When the voltage of the second resistor R2 is And the output of the first isolation operational amplifier U1 is Kv1* When the controller MCU or DSP detects the signal of Kv1* The level signal indicates that the first contactor K1 has a sticking fault; S3, the first contactor K1 can not close the fault detection: the controller MCU or DSP sends a closing signal of the first contactor K1 and performs a voltage detection of the second resistor R2. When the output of the first isolation operational amplifier U1 is Kv1* The controller MCU or DSP detects Kv1* When the voltage of the second resistor R2 is 0V, the first isolation operational amplifier U1 outputs a 0V signal, and the controller MCU or DSP detects a 0V level signal. At this time, the first contactor K1 fails and cannot be closed; S4, second contactor K2 adhesion fault detection: when the controller MCU or DSP does not send a closing signal for the second contactor K2, the voltage of the fourth resistor R4 is detected. When the voltage of the fourth resistor R4 is 0V and the second isolation operational amplifier U2 outputs a 0V signal, the controller MCU or DSP detects a 0V level signal. At this time, the second contactor K2 does not have an adhesion fault. When the voltage of the fourth resistor R4 is And the output of the second isolation operational amplifier U2 is Kv2* When the controller MCU or DSP detects the signal of Kv2* The level signal indicates that the second contactor K2 has a sticking fault; S5, the second contactor K2 cannot close the fault detection: the controller MCU or DSP sends a closing signal of the second contactor K2 and performs a voltage detection of the fourth resistor R4. When the second isolation operational amplifier U2 output is Kv2* The controller MCU or DSP detects Kv2* When the voltage of the fourth resistor R4 is 0V, the second isolation operational amplifier U2 outputs a 0V signal, the controller MCU or DSP detects a 0V level signal, and the second contactor K2 cannot be closed.

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