CN220085009U

CN220085009U - Magnetic latching relay disconnection delay detection system based on voltage change rate

Info

Publication number: CN220085009U
Application number: CN202321547994.XU
Authority: CN
Inventors: 于峥嵘
Original assignee: Nanjing Kapeng Technology Co ltd
Current assignee: Nanjing Kapeng Technology Co ltd
Priority date: 2023-06-16
Filing date: 2023-06-16
Publication date: 2023-11-24
Anticipated expiration: 2033-06-16

Abstract

The utility model discloses a magnetic latching relay disconnection delay detection system based on voltage change rate, which comprises: the microprocessor minimum system is electrically connected with the magnetic latching relay driving circuit; the magnetic latching relay driving circuit is electrically connected with a driving coil of the magnetic latching relay; the current zero-crossing detection circuit and the magnetic latching relay disconnection pulse detection circuit based on the voltage change rate are respectively and electrically connected with contacts of the magnetic latching relay. The utility model realizes the reliable detection of the disconnection delay of the magnetic latching relay of the compound switch type reactive compensation device and prolongs the service life of the magnetic latching relay.

Description

Magnetic latching relay disconnection delay detection system based on voltage change rate

Technical Field

The utility model belongs to the technical field of reactive power compensation, and particularly relates to a magnetic latching relay disconnection delay detection system based on a voltage change rate.

Background

The rapid development of national economy and the use of high-power transmission equipment lead to the increased reactive power demand of the power grid, thereby causing the larger voltage fluctuation of the power grid and the lower output of the generator. In order to solve the problem of low power quality caused by inductive reactive power, reactive power compensation devices are applied in large numbers to power distribution systems-! Reactive compensation is mainly carried out by contactor type (alternating current contactor), electronic switch type (thyristor switch) and compound switch type (microprocessor+magnetic latching relay) compensation systems at present. From the aspects of stability and economy, the composite switch type reactive power compensation system is an optimal scheme. And the service life of the compound switch type reactive compensation system is greatly influenced because of no reliable magnetic latching relay disconnection delay detection method.

Disclosure of Invention

In order to solve the defects in the prior art, the utility model provides the magnetic latching relay disconnection delay detection system based on the voltage change rate, so that the reliable detection of the magnetic latching relay disconnection delay of the compound switch type reactive compensation device is realized, and the service life of the magnetic latching relay is prolonged.

In order to achieve the above purpose, the technical scheme adopted by the utility model is as follows: a voltage change rate-based magnetic latching relay disconnection delay detection system, comprising: the microprocessor minimum system is electrically connected with the magnetic latching relay driving circuit; the magnetic latching relay driving circuit is electrically connected with a driving coil of the magnetic latching relay; the current zero-crossing detection circuit and the magnetic latching relay disconnection pulse detection circuit based on the voltage change rate are respectively and electrically connected with contacts of the magnetic latching relay.

Further, the microprocessor minimal system comprises: the single chip microcomputer U1, wherein a RELAY_S pin and a RELAY_R pin of the single chip microcomputer U1 are respectively connected with the input end of the magnetic latching RELAY driving circuit; the QT_PULSE pin of the singlechip U1 is connected with the output end of the magnetic latching relay disconnection PULSE detection circuit based on the voltage change rate; and the B_CUT pin of the singlechip U1 is connected with the output end of the current zero-crossing detection circuit.

Further, the model of the singlechip U1 is FM33LC046.

Further, the magnetic latching relay driving circuit includes: one end of the resistor R7 is connected with a RELAY_S pin of the singlechip U1, and the other end of the resistor R7 is connected with one end of the resistor R8 and a base electrode of the triode Q2; the other end of the resistor R8 and the emitter electrode of the triode Q2 are grounded; the collector of the triode Q2 is connected with one end of a resistor R10; the other end of the resistor R10 is respectively connected with one end of the resistor R11 and the base electrode of the triode Q3, and the other end of the resistor R11 and the emitter electrode of the triode Q3 are respectively connected with the voltage VCC1; the collector of the triode Q3 is respectively connected with the collector of the triode Q4, the cathode of the diode D1 and the anode of the diode D3; the cathode of the diode D3 is connected with a voltage VCC1; the base electrode of the triode Q4 is connected with the emitter electrode of the triode Q4 through a resistor R12 and grounded; the positive electrode of the diode D1 is grounded; the base electrode of the triode Q4 is connected with a RELAY_R pin of the singlechip U1 through a resistor R9; one end of the resistor R8 is connected with a RELAY_S pin of the singlechip U1, and the other end of the resistor R8 is connected with one end of the resistor R15 and a base electrode of the triode Q6; the other end of the resistor R15 and the emitter of the triode Q6 are respectively grounded; the collector of the triode Q6 is respectively connected with the cathode of the diode D5, the anode of the diode D4 and the collector of the triode Q5; the cathode of the diode D4 is connected with a voltage VCC1; the positive electrode of the diode D5 is grounded; the emitter of the triode Q5 is connected with a voltage VCC1; the base electrode of the triode Q5 is connected with a voltage VCC1 through a resistor R16, and is connected with the collector electrode of the triode Q7 through a resistor R17; the emitter of the triode Q7 is grounded; the base electrode of the triode Q7 is grounded through a resistor R19 and is connected with a RELAY_R pin of the singlechip U1 through a resistor R20; the positive electrode of the diode D3 and the positive electrode of the diode D4 are connected to the input terminal of the driving coil of the magnetic latching relay, respectively.

Further, the current zero-crossing detection circuit includes: a rectifier D6, wherein two input ports of the rectifier D6 are respectively connected with an UL port and an UN port of the magnetic latching relay; a diode D7 is connected in parallel with a resistor R21 and then is connected between two output ports of the rectifier D6; the common point of the cathode of the diode D7 and the resistor R21 is connected with the base electrode of the triode Q8 through the resistor R22; the cathode of the diode D7 is connected with the anode of the diode D8 at the common point of the resistor R21; the negative electrode of the diode D8 is respectively connected with one end of the capacitor C4 and the emitter of the triode Q9; the emitter of the triode Q8 is connected with the base electrode of the triode Q9 through a resistor R23; the collector of the triode Q8 is connected with one end of a resistor R24; the common point of the positive electrode of the diode D7 and the resistor R21 is connected with the other end of the capacitor C4, the other end of the resistor R24 and one end of the resistor R25; the other end of the resistor R25 and the collector electrode of the triode Q9 are respectively connected with the input end of the optocoupler N2; the collector of the triode Q10 is connected with one end of a resistor R27; the other end of the resistor R27 and the base electrode of the triode Q10 are respectively connected with the output end of the optocoupler N2; the base electrode of the triode Q10 is grounded through a resistor R26; the emitter of the triode Q10 is grounded; the other end of the resistor R27 is connected with a voltage VCC; the collector of the triode Q10 is connected with the B_CUTR pin of the singlechip U1.

Further, the UL port of the magnetic latching relay is connected with one contact of the switch K1 of the magnetic latching relay, and the UN port of the magnetic latching relay is connected with the other contact of the switch K1 of the magnetic latching relay through a capacitor C2.

Further, the magnetic latching relay off pulse detection circuit based on the voltage change rate includes: one input port of the rectifier D9 is respectively connected with one end of the capacitor C1 and one end of the resistor R1; the other end of the capacitor C1 and the other end of the resistor R1 are respectively connected with an IN port of the magnetic latching relay; the other input port of the rectifier D9 is connected with the OUT port of the magnetic latching relay, and the IN port and the OUT port of the magnetic latching relay are respectively connected with two contacts of a switch K1 of the magnetic latching relay; one output port of the rectifier D9 is respectively connected with one end of the resistor R2 and one end of the capacitor C3; one output port of the rectifier D9 is respectively connected with the other end of the resistor R2, one end of the resistor R3 and one end of the resistor R4; the other end of the resistor R3 is connected with the positive electrode of the diode D2, and the negative electrode of the diode D2 and the other end of the capacitor C3 are respectively connected with one of the input ports of the optocoupler N1; the other end of the resistor R4 is connected with the other input port of the optical coupler N1; the collector of the triode Q1 is connected with one end of a resistor R5; the other end of the resistor R5 and the base electrode of the triode Q1 are respectively connected with the output end of the optocoupler N1; the other end of the resistor R5 is connected with a voltage VCC; the base electrode of the triode Q1 is grounded through a resistor R6, and the emitter electrode of the triode Q1 is grounded; the collector of the triode Q1 is connected with the QT_PULSE pin of the singlechip U1.

Compared with the prior art, the utility model has the beneficial effects that: the utility model is electrically connected with a magnetic latching relay driving circuit through a microprocessor minimum system; the magnetic latching relay driving circuit is electrically connected with a driving coil of the magnetic latching relay; the current zero-crossing detection circuit and the magnetic latching relay disconnection pulse detection circuit based on the voltage change rate are respectively and electrically connected with the contacts of the magnetic latching relay, so that the reliable detection of the disconnection delay of the magnetic latching relay of the compound switch type reactive compensation device is realized, and the service life of the magnetic latching relay is prolonged.

Drawings

FIG. 1 is a schematic block diagram of a magnetic latching relay disconnection delay detection system based on a voltage change rate provided by an embodiment of the utility model;

FIG. 2 is a schematic diagram of a current zero crossing detection circuit in an embodiment of the utility model;

FIG. 3 is a schematic diagram of a microprocessor minimal system in accordance with an embodiment of the utility model;

FIG. 4 is a schematic diagram of a magnetic latching relay driving circuit in an embodiment of the present utility model;

FIG. 5 is a schematic diagram of a magnetic latching relay open pulse detection circuit based on voltage change rate in an embodiment of the present utility model;

fig. 6 is a schematic diagram of a magnetic latching relay in an embodiment of the present utility model.

Detailed Description

The utility model is further described below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present utility model, and are not intended to limit the scope of the present utility model.

As shown in fig. 1 to 6, a system for detecting a magnetic latching relay disconnection delay based on a voltage change rate includes: microprocessor minimal system 100, magnetic latching relay drive circuit 200, magnetic latching relay 300, current zero crossing detection circuit 400, and magnetic latching relay off pulse detection circuit 500 based on a rate of change of voltage.

The microprocessor minimal system 100 is electrically connected with the magnetic latching relay driving circuit 200; the magnetic latching relay driving circuit 200 is electrically connected to the driving coil of the magnetic latching relay 300.

The current zero-crossing detection circuit 400 and the magnetic latching relay off pulse detection circuit 500 based on the voltage change rate are electrically connected to contacts of the magnetic latching relay 300, respectively.

As shown in fig. 3, the microprocessor min-system 100 is used to handle the timing, driving, computing, etc. actions of the system, ensuring that the system operates reliably. The microprocessor minimum system 100 comprises a singlechip U1 (model FM33LC 046), wherein a RELAY_S pin (42 # pin) and a RELAY_R pin (43 # pin) of the singlechip U1 are respectively connected with the input end of the magnetic latching RELAY driving circuit 200; the QT_PULSE pin (44 # pin) of the singlechip U1 is connected with the output end of the magnetic latching relay disconnection PULSE detection circuit 500 based on the voltage change rate; the B_CUT pin (45 # pin) of the singlechip U1 is connected with the output end of the current zero-crossing detection circuit 400.

The pin 34# of the singlechip U1 is respectively connected with the voltage VCC, one end of the capacitor C6 and one end of the capacitor C7; the other end of the capacitor C6 and the other end of the capacitor C7 are grounded, so that the single-chip microcomputer is filtered by a power supply and is ensured to run stably and reliably by decoupling.

The 50# pin of the singlechip U1 is grounded through the capacitor C10, so that power supply filtering is provided for the singlechip core, and the core operation is stabilized.

The 52# pin of the singlechip U1 is respectively connected with the voltage VCC, one end of the capacitor C8 and one end of the capacitor C9; the other end of the capacitor C8 and the other end of the capacitor C9 are grounded, so that the single-chip microcomputer is filtered by a power supply and is decoupled, and stable and reliable operation of the single-chip microcomputer is ensured.

The 54# pin of the singlechip U1 is respectively connected with the voltage VCC, one end of the capacitor C8 and one end of the capacitor C9; the other end of the capacitor C8 and the other end of the capacitor C9 are grounded, so that a stable power supply and decoupling are provided for the AD converter arranged outside the singlechip, and the AD can be ensured to run stably and reliably.

The 63# pin of the singlechip U1 is connected with the SWCLK pin of the pin connector P1; the 64# pin of the singlechip U1 is connected with the SWDIO pin of the pin connector P1; the VCC pin of the pin connector P1 is respectively connected with a voltage VCC, one end of a resistor R13 and one end of a resistor R14; the other end of the resistor R13 is connected with the SWDIO pin of the pin connector P1, the other end of the resistor R14 is connected with the SWCLK pin of the pin connector P1, and the simulation, debugging and downloading program interfaces of the singlechip are realized, so that the maintainability and secondary development feasibility of the system are ensured.

The NRST pin (1 # pin) of the singlechip U1 is connected with the NRST pin of the pin connector P1, so that reliable simulation and reset are ensured.

As shown in fig. 4, a magnetic latching relay driving circuit 200 is provided. One end of a resistor R7 is connected with a RELAY_S pin of the singlechip U1, and the other end of the resistor R7 is connected with one end of a resistor R8 and a base electrode of a triode Q2; the other end of the resistor R8 and the emitter electrode of the triode Q2 are grounded; the collector of the triode Q2 is connected with one end of a resistor R10; the other end of the resistor R10 is respectively connected with one end of the resistor R11 and the base electrode of the triode Q3, and the other end of the resistor R11 and the emitter electrode of the triode Q3 are respectively connected with the voltage VCC1; the collector of the triode Q3 is respectively connected with the collector of the triode Q4, the cathode of the diode D1 and the anode of the diode D3; the cathode of the diode D3 is connected with a voltage VCC1; the base electrode of the triode Q4 is connected with the emitter electrode of the triode Q4 through a resistor R12 and grounded; the positive electrode of the diode D1 is grounded; the base electrode of the triode Q4 is connected with a RELAY_R pin of the singlechip U1 through a resistor R9.

One end of a resistor R8 is connected with a RELAY_S pin of the singlechip U1, and the other end of the resistor R8 is connected with one end of a resistor R15 and a base electrode of a triode Q6; the other end of the resistor R15 and the emitter of the triode Q6 are respectively grounded; the collector of the triode Q6 is respectively connected with the cathode of the diode D5, the anode of the diode D4 and the collector of the triode Q5; the cathode of the diode D4 is connected with a voltage VCC1; the positive electrode of the diode D5 is grounded; the emitter of the triode Q5 is connected with a voltage VCC1; the base electrode of the triode Q5 is connected with a voltage VCC1 through a resistor R16, and is connected with the collector electrode of the triode Q7 through a resistor R17; the emitter of the triode Q7 is grounded; the base electrode of the triode Q7 is grounded through a resistor R19 and is connected with a RELAY_R pin of the singlechip U1 through a resistor R20.

The positive electrode of the diode D3 and the positive electrode of the diode D4 are connected to the input terminal of the driving coil of the magnetic latching relay 300, respectively.

The driving signal RELAY_ S, RELAY _R sent by the singlechip U1 is connected to the magnetic latching RELAY driving circuit 200 and is input into triodes Q2 and Q7; the triodes Q3, Q4, Q5 and Q6 are connected to form a driving bridge arm, and the diodes D1, D3, D4 and D5 form a driving bridge arm freewheel loop, so that the magnetic latching relay driving circuit 200 is formed.

The operating principle of the magnetic latching relay driving circuit 200 is as follows:

1) When the input signal RELAY_S is high and RELAY_R is low, the triodes Q2 and Q6 are turned on, and the triodes Q4 and Q7 are turned off; the triode Q2 is conducted to lead the triode Q3 to be conducted, the triode Q7 is cut off to lead the triode Q5 to be cut off, and therefore the magnetic latching relay K1 is conducted after being subjected to forward voltage;

2) When the input signal RELAY_S is low and RELAY_R is high, the triodes Q4 and Q7 are turned on, the triodes Q2 and Q6 are turned off, the triodes Q7 are turned on to cause the triodes Q5 to be turned on, and the triodes Q2 are turned off to cause the triodes Q3 to be turned off, so that the magnetic latching RELAY K1 is turned off under the reverse voltage.

As shown in fig. 2, is a current zero crossing detection circuit 400. Two input ports of the rectifier D6 are respectively connected with an UL port and an UN port of the magnetic latching relay 300; a diode D7 is connected in parallel with a resistor R21 and then is connected between two output ports of the rectifier D6; the common point of the cathode of the diode D7 and the resistor R21 is connected with the base electrode of the triode Q8 through the resistor R22; the cathode of the diode D7 is connected with the anode of the diode D8 at the common point of the resistor R21; the negative electrode of the diode D8 is respectively connected with one end of the capacitor C4 and the emitter of the triode Q9; the emitter of the triode Q8 is connected with the base electrode of the triode Q9 through a resistor R23; the collector of transistor Q8 is connected to one end of resistor R24.

The common point of the positive electrode of the diode D7 and the resistor R21 is connected with the other end of the capacitor C4, the other end of the resistor R24 and one end of the resistor R25; the other end of the resistor R25 and the collector electrode of the triode Q9 are respectively connected with the input end of the optocoupler N2.

The collector of the triode Q10 is connected with one end of a resistor R27; the other end of the resistor R27 and the base electrode of the triode Q10 are respectively connected with the output end of the optocoupler N2; the base electrode of the triode Q10 is grounded through a resistor R26; the emitter of the triode Q10 is grounded; the other end of the resistor R27 is connected with a voltage VCC; the collector of the triode Q10 is connected with the B_CUTR pin of the singlechip U1.

As shown in fig. 2 and 6, the UL port of the magnetic latching relay 300 is connected to one contact of the switch K1 of the magnetic latching relay 300, and the UN port of the magnetic latching relay 300 is connected to the other contact of the switch K1 of the magnetic latching relay 300 via the capacitor C2.

The current zero-crossing detection circuit 400 uses the relationship of the capacitance current and the voltage phase difference of 90 degrees to detect the zero crossing point of the power supply voltage as the system current zero-crossing point.

When the voltage between UL and UN is 0 (+ -1V), the capacitor C4 discharges through the triodes Q8 and Q9, and simultaneously drives the optocoupler N2, and the current amplifying triode Q10 generates a low-level pulse QT_PLUSE; when the voltage between the UL and the UN is not 0 (more than 1V), the triodes Q8, Q9 and Q10 are cut off, and a high level QT_PLUSE is output; the signal is connected to the microprocessor minimum system 100, and the microprocessor minimum system 100 performs a processing operation.

As shown in fig. 5, the magnetic latching relay off pulse detection circuit is based on the voltage change rate. One input port of the rectifier D9 is respectively connected with one end of the capacitor C1 and one end of the resistor R1; the other end of the capacitor C1 and the other end of the resistor R1 are respectively connected with the IN port of the magnetic latching relay 300; the other input port of the rectifier D9 is connected to the OUT port of the magnetic latching relay 300, and the IN port and the OUT port of the magnetic latching relay 300 are respectively connected to two contacts of the switch K1 of the magnetic latching relay 300.

One output port of the rectifier D9 is respectively connected with one end of the resistor R2 and one end of the capacitor C3; one output port of the rectifier D9 is respectively connected with the other end of the resistor R2, one end of the resistor R3 and one end of the resistor R4; the other end of the resistor R3 is connected with the positive electrode of the diode D2, and the negative electrode of the diode D2 and the other end of the capacitor C3 are respectively connected with one of the input ports of the optocoupler N1; the other end of the resistor R4 is connected with the other input port of the optical coupler N1.

The collector of the triode Q1 is connected with one end of a resistor R5; the other end of the resistor R5 and the base electrode of the triode Q1 are respectively connected with the output end of the optocoupler N1; the other end of the resistor R5 is connected with a voltage VCC; the base of the triode Q1 is grounded through a resistor R6, and the emitter of the triode Q1 is grounded.

The collector of the triode Q1 is connected with the QT_PULSE pin of the singlechip U1.

The working principle of the magnetic latching relay disconnection pulse detection circuit based on the voltage change rate is as follows:

when the switch K1 of the magnetic latching relay 300 is turned off, at the moment of turning off the K1 contact, the voltage between the two ends IN and OUT of the K1 contact is equal to the power supply voltages UL and UN, because R1 and C1 are connected IN parallel with the two ends of the switch contact through the rectifier bridge D9, so that at the moment of turning off the C1 voltage jumps from 0V to the power supply voltage, because the C1 current i=c1×du/dt, du is the power supply voltage when the contact is turned off, and dt is the contact turn-off time; the off-time dt tends to 0 due to the mechanical contact, so that the voltage change rate du/dt of the capacitor C1 is large, and thus a high pulse current flows through C1; this current produces a spike in voltage across R2 through rectifier bridge D9, which produces a large voltage jump. Similarly, a large pulse current is generated on the capacitor C3 due to the large voltage change rate of the two ends of the R2, so that the optocoupler N1 is directly driven to be conducted through the R4; in this way, the signal is amplified by an amplifying circuit formed by the resistors R5 and R6 and the triode Q1, so that the Q1 is saturated and conducted, a low-level PULSE signal QT_PULSE is generated, the signal is connected into the singlechip U1, and the singlechip U1 captures the falling edge of the signal.

As shown in fig. 6, the magnetic latching relay and the actuator of the reactive compensation system of the compound switch type are adopted. Mainly comprises a driving coil, a switch K1 and a compensation capacitor. The magnetic latching relay is mainly used for responding to the action of the magnetic latching relay driving circuit, so as to cut off the capacitance, reduce the capacitive reactive power of the system and ensure the long-term and stable operation of the compound switch type reactive power compensation system.

The utility model comprises a micro-processing minimum system formed by a singlechip U1, when the system detects a current zero crossing signal, a cutting delay timer is started, a magnetic latching RELAY is delayed to last detect the cutting delay time, a magnetic latching RELAY cutting instruction is sent (RELAY_S is low level, RELAY_R is high level), a delay counter is started, the magnetic latching RELAY is cut off through a magnetic latching RELAY driving circuit, and a magnetic latching RELAY contact cutting pulse is generated by a magnetic latching RELAY cutting pulse detection circuit based on the voltage change rate at the cutting moment; and when the microprocessor detects the pulse, the delay counter is closed, and the time value is transmitted to the cut-off delay timer to prepare for cutting off the magnetic latching relay next time. Therefore, the disconnection delay time of the magnetic latching relay can be detected in real time through the detection system, and the reliable operation of the compound switch type reactive compensation device is ensured.

The utility model realizes the reliable detection of the disconnection delay of the magnetic latching relay of the traditional compound switch type reactive compensation system, and ensures the longer service life and more reliable work of the compound switch type reactive compensation system.

The foregoing is merely a preferred embodiment of the present utility model, and it should be noted that modifications and variations could be made by those skilled in the art without departing from the technical principles of the present utility model, and such modifications and variations should also be regarded as being within the scope of the utility model.

Claims

1. A magnetic latching relay disconnection delay detection system based on a voltage change rate, comprising: a microprocessor minimum system (100), the microprocessor minimum system (100) being electrically connected to the magnetic latching relay drive circuit (200); the magnetic latching relay driving circuit (200) is electrically connected with a driving coil of the magnetic latching relay (300);

a current zero-crossing detection circuit (400) and a magnetic latching relay off pulse detection circuit (500) based on a voltage change rate are electrically connected to contacts of the magnetic latching relay (300), respectively.

2. The voltage change rate-based magnetic latching relay disconnection delay detection system of claim 1, wherein said microprocessor minimum system (100) comprises:

the single chip microcomputer U1, a RELAY_S pin and a RELAY_R pin of the single chip microcomputer U1 are respectively connected with the input end of the magnetic latching RELAY driving circuit (200);

the QT_PULSE pin of the singlechip U1 is connected with the output end of a magnetic latching relay disconnection PULSE detection circuit (500) based on the voltage change rate;

the B_CUT pin of the singlechip U1 is connected with the output end of the current zero-crossing detection circuit (400).

3. The voltage change rate-based magnetic latching relay disconnection delay detection system according to claim 2, wherein the model of the single-chip microcomputer U1 is FM33LC046.

4. The voltage change rate-based magnetic latching relay disconnection delay detection system according to claim 2, wherein the magnetic latching relay driving circuit (200) comprises:

one end of the resistor R7 is connected with a RELAY_S pin of the singlechip U1, and the other end of the resistor R7 is connected with one end of the resistor R8 and a base electrode of the triode Q2; the other end of the resistor R8 and the emitter electrode of the triode Q2 are grounded; the collector of the triode Q2 is connected with one end of a resistor R10; the other end of the resistor R10 is respectively connected with one end of the resistor R11 and the base electrode of the triode Q3, and the other end of the resistor R11 and the emitter electrode of the triode Q3 are respectively connected with the voltage VCC1; the collector of the triode Q3 is respectively connected with the collector of the triode Q4, the cathode of the diode D1 and the anode of the diode D3; the cathode of the diode D3 is connected with a voltage VCC1; the base electrode of the triode Q4 is connected with the emitter electrode of the triode Q4 through a resistor R12 and grounded; the positive electrode of the diode D1 is grounded; the base electrode of the triode Q4 is connected with a RELAY_R pin of the singlechip U1 through a resistor R9;

one end of the resistor R8 is connected with a RELAY_S pin of the singlechip U1, and the other end of the resistor R8 is connected with one end of the resistor R15 and a base electrode of the triode Q6; the other end of the resistor R15 and the emitter of the triode Q6 are respectively grounded; the collector of the triode Q6 is respectively connected with the cathode of the diode D5, the anode of the diode D4 and the collector of the triode Q5; the cathode of the diode D4 is connected with a voltage VCC1; the positive electrode of the diode D5 is grounded; the emitter of the triode Q5 is connected with a voltage VCC1; the base electrode of the triode Q5 is connected with a voltage VCC1 through a resistor R16, and is connected with the collector electrode of the triode Q7 through a resistor R17; the emitter of the triode Q7 is grounded; the base electrode of the triode Q7 is grounded through a resistor R19 and is connected with a RELAY_R pin of the singlechip U1 through a resistor R20;

the positive electrode of the diode D3 and the positive electrode of the diode D4 are respectively connected with the input end of the driving coil of the magnetic latching relay (300).

5. The voltage change rate-based magnetic latching relay disconnection delay detection system of claim 2, wherein the current zero crossing detection circuit (400) comprises:

a rectifier D6, wherein two input ports of the rectifier D6 are respectively connected with an UL port and an UN port of the magnetic latching relay (300); a diode D7 is connected in parallel with a resistor R21 and then is connected between two output ports of the rectifier D6; the common point of the cathode of the diode D7 and the resistor R21 is connected with the base electrode of the triode Q8 through the resistor R22; the cathode of the diode D7 is connected with the anode of the diode D8 at the common point of the resistor R21; the negative electrode of the diode D8 is respectively connected with one end of the capacitor C4 and the emitter of the triode Q9; the emitter of the triode Q8 is connected with the base electrode of the triode Q9 through a resistor R23; the collector of the triode Q8 is connected with one end of a resistor R24;

the common point of the positive electrode of the diode D7 and the resistor R21 is connected with the other end of the capacitor C4, the other end of the resistor R24 and one end of the resistor R25; the other end of the resistor R25 and the collector electrode of the triode Q9 are respectively connected with the input end of the optocoupler N2;

6. The voltage change rate-based magnetic latching relay disconnection delay detection system according to claim 5, wherein the UL port of the magnetic latching relay (300) is connected to one contact of the switch K1 of the magnetic latching relay (300), and the UN port of the magnetic latching relay (300) is connected to the other contact of the switch K1 of the magnetic latching relay (300) through a capacitor C2.

7. The voltage change rate-based magnetic latching relay disconnection delay detection system according to claim 2, wherein the voltage change rate-based magnetic latching relay disconnection pulse detection circuit (500) includes: one input port of the rectifier D9 is respectively connected with one end of the capacitor C1 and one end of the resistor R1; the other end of the capacitor C1 and the other end of the resistor R1 are respectively connected with an IN port of the magnetic latching relay (300); the other input port of the rectifier D9 is connected with the OUT port of the magnetic latching relay (300), and the IN port and the OUT port of the magnetic latching relay (300) are respectively connected with two contacts of a switch K1 of the magnetic latching relay (300);

one output port of the rectifier D9 is respectively connected with one end of the resistor R2 and one end of the capacitor C3; one output port of the rectifier D9 is respectively connected with the other end of the resistor R2, one end of the resistor R3 and one end of the resistor R4; the other end of the resistor R3 is connected with the positive electrode of the diode D2, and the negative electrode of the diode D2 and the other end of the capacitor C3 are respectively connected with one of the input ports of the optocoupler N1; the other end of the resistor R4 is connected with the other input port of the optical coupler N1;

the collector of the triode Q1 is connected with one end of a resistor R5; the other end of the resistor R5 and the base electrode of the triode Q1 are respectively connected with the output end of the optocoupler N1; the other end of the resistor R5 is connected with a voltage VCC; the base electrode of the triode Q1 is grounded through a resistor R6, and the emitter electrode of the triode Q1 is grounded;