A circuit for suppressing induced electromotive force caused by start-stop of an electromagnetic lock

Abstract

The utility model relates to EMC new energy automobile technical field, specifically is a kind of induced electromotive force circuit caused by inhibiting electromagnetic lock start-stop, it is connected between new energy automobile power Better and control pin EN, wherein induced electromotive force circuit includes: power filter module, voltage absorption module and control end protection module;And through specific electrical connection relationship, form three-grade protection structure, synergic inhibition induced electromotive force-power filter module stabilizes input fluctuation, voltage absorption module clamps coil surge voltage, control end protection module isolates MCU interference, to solve the problem that electromagnetic lock start-stop when induced electromotive force interferes with car machine equipment and burns fuse, experiment shows that this circuit can the induced electromotive force peak value is inhibited to 1.3 times within power voltage, EMC test passes ISO 7637-2 standard.

Description

Technical Field

[0001] This utility model relates to the field of EMC new energy vehicle technology, specifically a circuit for suppressing induced electromotive force caused by the start and stop of an electromagnetic lock. Background Technology

[0002] With the current promotion of intelligent technology in new energy vehicles, the market for electromagnetic locks has been vigorously developed. Electromagnetic locks rely on a solenoid coil to generate a magnetic field to attract or release objects, thus achieving a switching function. However, EMC issues have been found when electromagnetic locks are used in new energy vehicles. Specifically, the circuitry of electromagnetic locks is very simple, typically drawing power directly from the vehicle's main power supply circuit, making it extremely prone to interfering with other products or electronic devices. A simplified circuit diagram is shown below. Figure 1 As shown, Better: the car battery, providing power input; FS: a fuse, protecting the circuit from open circuit failure; JDQ: a relay, controlling the opening and closing of the electromagnetic lock; coil: the solenoid coil of the electromagnetic lock, generating magnetic force; EN: a control pin, for externally provided control signals. Using this electromagnetic lock circuit often affects other products or causes malfunctions. Utility Model Content

[0003] In view of this, the purpose of this utility model is to provide a circuit for suppressing the induced electromotive force caused by the start and stop of an electromagnetic lock, so as to overcome the problems mentioned in the background art.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0005] A circuit for suppressing induced electromotive force caused by the start and stop of an electromagnetic lock is connected between the power supply Better and the control pin EN of a new energy vehicle, including: a power supply filtering module, a voltage absorption module and a control terminal protection module;

[0006] The input terminal of the power filtering module is connected to the Better power supply of the new energy vehicle, and the output terminal of the power filtering module is connected to a relay. The power filtering module includes an electrolytic capacitor C+ and an inductor L connected in parallel.

[0007] The voltage absorption module is connected between the relay JDQ and the electromagnetic lock coil. The voltage absorption module includes a Zener diode DV and an overvoltage protection diode TVS.

[0008] The control terminal protection module is connected to the control pin EN and the relay JDQ respectively. The control terminal protection module includes an ESD suppression diode and a non-polar high voltage capacitor C connected in series.

[0009] Preferably, it also includes a fuse FS, which is connected in series between the new energy vehicle power supply Better and the power filter module.

[0010] Preferably, one end of the electrolytic capacitor C+ is electrically connected to one end of the fuse FS and one end of the inductor L, the other end of the electrolytic capacitor C+ is grounded, and the other end of the inductor L is electrically connected to the negative terminal of the Zener diode DV, one end of the overvoltage protection diode TVS, and the fourth pin of the relay JDQ.

[0011] Preferably, the positive terminal of the Zener diode DV and the other end of the overvoltage protection diode TVS are both grounded.

[0012] Preferably, the negative terminal of the electrostatic discharge diode ESD and one end of the non-polarized high-voltage capacitor C are both connected to the path between the control pin EN and the first pin of the relay JDQ, and the positive terminal of the electrostatic discharge diode ESD and the other end of the non-polarized high-voltage capacitor C are both grounded.

[0013] Preferably, the third pin of the relay JDQ is electrically connected to one end of the electromagnetic lock coil, and the other end of the electromagnetic lock coil is electrically connected to the second pin of the relay JDQ and both are grounded.

[0014] Preferably, in the power supply filtering module, the capacitance value of the electrolytic capacitor C+ ranges from 100μF to 1000μF, and the inductance value of the inductor L ranges from 10μH to 100μH, together forming an LC filter network.

[0015] Preferably, the breakdown voltage of the Zener diode DV is 1.2-1.5 times the power supply voltage; the overvoltage protection diode TVS is connected in parallel with the Zener diode DV, with a response time ≤1ns and a peak power ≥600W.

[0016] Preferably, the capacitance value C of the non-polar high-voltage capacitor C of the control terminal protection module is in the range of 0.1μF-1μF, the withstand voltage is ≥50V, and it is connected in series between the control pin EN and the relay JDQ; the electrostatic discharge suppression diode ESD is a bidirectional TVS diode with a clamping voltage ≤24V, and it is connected in parallel between the control pin EN and ground.

[0017] The beneficial effects of this utility model are:

[0018] This utility model provides a circuit for suppressing induced electromotive force caused by the start and stop of an electromagnetic lock. It is connected between the Better power supply and the EN control pin of a new energy vehicle. The induced electromotive force circuit includes a power supply filtering module, a voltage absorption module, and a control terminal protection module. Through specific electrical connections, a three-level protection structure is formed to synergistically suppress the induced electromotive force: the power supply filtering module smooths input fluctuations, the voltage absorption module clamps coil surge voltage, and the control terminal protection module isolates MCU interference. This solves the problem of induced electromotive force interfering with vehicle equipment and burning out fuses when the electromagnetic lock starts and stops. Experiments show that this circuit can suppress the peak value of the induced electromotive force to within 1.3 times the power supply voltage, and EMC testing meets the ISO 7637-2 standard. Attached Figure Description

[0019] Figure 1 This is a circuit connection diagram in the background technology of this utility model;

[0020] Figure 2 This is a circuit connection diagram of a circuit for suppressing the induced electromotive force caused by the start and stop of an electromagnetic lock according to this utility model. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0022] See Figure 2 The present invention provides a circuit for suppressing the induced electromotive force caused by the start and stop of an electromagnetic lock, which is connected between the power supply Better and the control pin EN of a new energy vehicle, and includes: a power supply filtering module, a voltage absorption module and a control terminal protection module.

[0023] The input terminal of the power filtering module is connected to the Better power supply of the new energy vehicle, and the output terminal of the power filtering module is connected to a relay. The power filtering module includes an electrolytic capacitor C+ and an inductor L connected in parallel.

[0024] The voltage absorption module is connected between the relay JDQ and the electromagnetic lock coil. The voltage absorption module includes a Zener diode DV and an overvoltage protection diode TVS.

[0025] The control terminal protection module is connected to the control pin EN and the relay JDQ respectively. The control terminal protection module includes an ESD suppression diode and a non-polar high voltage capacitor C connected in series.

[0026] The beneficial effects of this utility model are:

[0027] This utility model provides a circuit for suppressing induced electromotive force caused by the start and stop of an electromagnetic lock. It is connected between the Better power supply and the EN control pin of a new energy vehicle. The induced electromotive force circuit includes a power supply filtering module, a voltage absorption module, and a control terminal protection module. Through specific electrical connections, a three-level protection structure is formed to synergistically suppress the induced electromotive force: the power supply filtering module smooths input fluctuations, the voltage absorption module clamps coil surge voltage, and the control terminal protection module isolates MCU interference. This solves the problem of induced electromotive force interfering with vehicle equipment and burning out fuses when the electromagnetic lock starts and stops. Experiments show that this circuit can suppress the peak value of the induced electromotive force to within 1.3 times the power supply voltage, and EMC testing meets the ISO 7637-2 standard.

[0028] Preferably, the system also includes a fuse FS, which is connected in series between the new energy vehicle power supply Better and the power filter module. The fuse FS, connected in series between the new energy vehicle power supply Better and the power filter module, provides protection. The fusing current of the fuse FS is 1.5-2 times the rated current of the circuit.

[0029] Preferably, one end of the electrolytic capacitor C+ is electrically connected to one end of the fuse FS and one end of the inductor L, and the other end of the electrolytic capacitor C+ is grounded. The other end of the inductor L is electrically connected to the negative terminal of the Zener diode DV, one end of the overvoltage protection diode TVS, and the fourth pin of the relay JDQ. The positive terminal of the Zener diode DV and the other end of the overvoltage protection diode TVS are both grounded. This specific connection method forms a voltage absorption module, achieving the function of clamping the surge voltage of the coil.

[0030] Preferably, the negative terminal of the ESD suppression diode and one end of the non-polarized high-voltage capacitor C are both connected to the path between the control pin EN and the first pin of the relay JDQ, while the positive terminal of the ESD suppression diode and the other end of the non-polarized high-voltage capacitor C are both grounded. This specific connection method forms a control-end protection module, which isolates MCU interference.

[0031] Preferably, the third pin of the relay JDQ is electrically connected to one end of the electromagnetic lock coil, and the other end of the electromagnetic lock coil is electrically connected to the second pin of the relay JDQ and both are grounded, thus satisfying the electrical connection requirements of the relay JDQ.

[0032] In this embodiment, the relay JDQ is a normally open automotive relay with a coil drive voltage of 12V / 24VDC and a contact load capacity of ≥30A. The electromagnetic lock coil has a solenoid structure with a DC resistance of ≤5Ω and an inductance of ≥10mH.

[0033] Preferably, in the power supply filtering module, the capacitance value of the electrolytic capacitor C+ ranges from 100μF to 1000μF, and the inductance value of the inductor L ranges from 10μH to 100μH, together forming an LC filter network. Using components with the above-mentioned specific parameters meets the actual need to smooth out input fluctuations.

[0034] Preferably, the breakdown voltage of the Zener diode DV is 1.2-1.5 times the power supply voltage; the overvoltage protection diode TVS is connected in parallel with the Zener diode DV, with a response time ≤1ns and a peak power ≥600W. Using components with the above-mentioned specific parameters achieves the function of clamping the surge voltage of the coil.

[0035] Preferably, the non-polar high-voltage capacitor C of the control terminal protection module has a capacitance range of 0.1μF-1μF and a withstand voltage of ≥50V, and is connected in series between the control pin EN and the relay JDQ; the ESD suppression diode is a bidirectional TVS diode with a clamping voltage ≤24V, and is connected in parallel between the control pin EN and ground. Using components with the above-mentioned specific parameters serves to isolate MCU interference.

[0036] In this embodiment, the power supply voltage is 12V DC, the electrolytic capacitor C+ is a 470μF electrolytic capacitor (with a withstand voltage of 25V); the inductor L is a 47μH power inductor (saturation current 20A); the Zener diode DV is a 15V Zener diode (1N4744A); the overvoltage protection diode TVS is model SMBJ15CA (15V / 600W); the ESD suppression diode is model PESD5V0S1BT (clamping voltage 9V); and the non-polarized high-voltage capacitor C is a 0.47μF ceramic capacitor (X7R / 50V).

[0037] Work process:

[0038] 1. When the EN pin is high, the relay JDQ is energized, and the electromagnetic lock coil generates a magnetic field.

[0039] 2. When the coil current changes abruptly, the TVS / DV clamps the reverse electromotive force to below 14.5V within 1μs;

[0040] 3. ESD and capacitor C absorb surges at the control terminal to ensure that the voltage fluctuation of the MCU pin is ≤0.5V;

[0041] 4. When the power is off, the LC filter network absorbs the return voltage of the power supply to prevent the fuse from blowing.

[0042] This utility model has been described with reference to the above-described embodiments and accompanying drawings. However, the above embodiments are merely examples for implementing this utility model. It must be noted that the disclosed embodiments do not limit the scope of this utility model. On the contrary, modifications and equivalent provisions included in the spirit and scope of the claims are all included within the scope of this utility model.

Claims

1. A circuit for suppressing induced electromotive force caused by the start and stop of an electromagnetic lock, connected between the power supply Better and the control pin EN of a new energy vehicle, characterized in that... include: Power filtering module, voltage absorption module, and control terminal protection module; The input terminal of the power filtering module is connected to the Better power supply of the new energy vehicle, and the output terminal of the power filtering module is connected to a relay. The power filtering module includes an electrolytic capacitor C+ and an inductor L connected in parallel. The voltage absorption module is connected between the relay JDQ and the electromagnetic lock coil. The voltage absorption module includes a Zener diode DV and an overvoltage protection diode TVS. The control terminal protection module is connected to the control pin EN and the relay JDQ respectively. The control terminal protection module includes an ESD suppression diode and a non-polar high voltage capacitor C connected in series.

2. The circuit for suppressing induced electromotive force caused by the start and stop of an electromagnetic lock according to claim 1, characterized in that, It also includes a fuse FS, which is connected in series between the new energy vehicle power supply Better and the power filter module.

3. The circuit for suppressing induced electromotive force caused by the start and stop of an electromagnetic lock according to claim 2, characterized in that, One end of the electrolytic capacitor C+ is electrically connected to one end of the fuse FS and one end of the inductor L, respectively. The other end of the electrolytic capacitor C+ is grounded. The other end of the inductor L is electrically connected to the negative terminal of the Zener diode DV, one end of the overvoltage protection diode TVS, and the fourth pin of the relay JDQ.

4. The circuit for suppressing induced electromotive force caused by the start and stop of an electromagnetic lock according to claim 3, characterized in that, The positive terminal of the Zener diode DV and the other end of the overvoltage protection diode TVS are both grounded.

5. The circuit for suppressing induced electromotive force caused by the start and stop of an electromagnetic lock according to claim 1, characterized in that, The negative terminal of the electrostatic discharge (ESD) diode and one end of the non-polarized high-voltage capacitor C are both connected to the path between the control pin EN and the first pin of the relay JDQ, while the positive terminal of the ESD diode and the other end of the non-polarized high-voltage capacitor C are both grounded.

6. The circuit for suppressing induced electromotive force caused by the start and stop of an electromagnetic lock according to claim 1, characterized in that, The third pin of the relay JDQ is electrically connected to one end of the electromagnetic lock coil, and the other end of the electromagnetic lock coil is electrically connected to the second pin of the relay JDQ and both are grounded.

7. The circuit for suppressing induced electromotive force caused by the start and stop of an electromagnetic lock according to claim 1, characterized in that: The electrolytic capacitor C+ in the power supply filter module has a capacitance range of 100μF-1000μF, and the inductor L has an inductance range of 10μH-100μH. Together, they form an LC filter network.

8. The circuit for suppressing induced electromotive force caused by the start and stop of an electromagnetic lock according to claim 1, characterized in that: The breakdown voltage of the Zener diode DV is 1.2-1.5 times the power supply voltage; the overvoltage protection diode TVS is connected in parallel with the Zener diode DV, with a response time ≤1ns and a peak power ≥600W.

9. The circuit for suppressing induced electromotive force caused by the start and stop of an electromagnetic lock according to claim 1, characterized in that: The non-polar high-voltage capacitor C of the control terminal protection module has a capacitance range of 0.1μF-1μF and a withstand voltage of ≥50V, and is connected in series between the control pin EN and the relay JDQ; the electrostatic discharge suppression diode ESD is a bidirectional TVS diode with a clamping voltage ≤24V, and is connected in parallel between the control pin EN and ground.

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