Anti-back electromotive force circuit

Abstract

The utility model provides an anti-counter electromotive force circuit, which comprises a power supply input end, a power supply output end, an anti-counter assembly, a counter electromotive force absorption assembly, an anti-counter state switching assembly, an energy cache assembly, a counter electromotive force release assembly and a power supply assembly. And the anti-reverse assembly is used for preventing reverse electromotive force generated by the load from impacting the power supply. The back electromotive force absorption assembly is used for absorbing back electromotive force generated by the load. And the back electromotive force release assembly is used for releasing the back electromotive force in the absorption assembly. When no back electromotive force is recovered, a transient impact energy caching assembly in the energy caching assembly performs energy caching on an instantaneous large energy signal of the anti-reverse assembly, and a back electromotive force auxiliary caching assembly in the energy caching assembly performs auxiliary absorption on the back electromotive force; the transient impact energy caching assembly and the back electromotive force auxiliary caching assembly release cached energy and merge the cached energy into a main loop, so that sudden change energy interference in the protection process is effectively restrained, and meanwhile the part of energy is prevented from being wasted.

Description

TECHNICAL FIELD

[0001] The utility model relates to electronic technical field, especially a kind of anti-reverse electromotive force circuit. BACKGROUND

[0002] In power electronic applications, motor as typical inductive load, is widely used in industrial automation, household appliances, vehicles and other fields. However, when the motor decelerates from high-speed running state to stop or suddenly power off, the magnetic field in its internal coil will not disappear immediately, but according to Faraday's law of electromagnetic induction, a high-amplitude reverse electromotive force (Back-EMF) opposite to the power supply direction will be generated at both ends of the coil. This momentary high-voltage and high-current energy, if not properly handled, will be directly fed back to the power supply, posing a serious threat to the power supply system.

[0003] Traditional power supply design often lacks effective protection measures against such reverse electromotive force impact, resulting in overvoltage and overcurrent protection action of the power supply when encountering such situations, and even direct damage to internal electronic components such as rectifier bridge and power switch tube. This not only increases the maintenance cost of the equipment, but also seriously affects the stability and efficiency of the system. In order to solve the above problems, some simple protection schemes have appeared in the market, such as adding pressure-sensitive resistors, transient voltage suppression diodes (TVS) and other passive components to absorb part of the reverse energy. For example, Chinese utility model patent CN218124309U discloses a method for protecting power supply from reverse electromotive force impact by using diodes. However, the diodes are also connected to the circuit for a long time when there is no reverse electromotive force, causing unnecessary energy consumption. When the reverse electromotive force comes, the anode of the diode is impacted due to the instantaneous cathode voltage being greater than the anode, causing the energy to be transferred to the cathode, which is a momentary large energy disturbance signal, thus interfering with the circuit. SUMMARY

[0004] To solve the above problems, the purpose of the utility model is to provide an anti-reverse electromotive force circuit, which short-circuits the anti-reverse component when there is no reverse electromotive force in the circuit, thus avoiding continuous energy consumption of the anti-reverse component, and suppressing and buffering the momentary large energy disturbance signal when the circuit generates it.

[0005] The utility model realizes the following technical solutions:

[0006] An anti-reverse electromotive force circuit, comprising:

[0007] An anti-reverse component connected in series between the power supply input and the power supply output;

[0008] A reverse electromotive force absorbing component, one end of the absorbing component connected between the anti-reverse component and the power supply output, and the other end grounded.

[0009] The anti-reverse state switching component has a common terminal, a normally closed contact and a normally open contact, and the common terminal and the normally closed contact are connected to two ends of the anti-reverse component respectively;

[0010] The transient impact energy storage component has an input end connected to the normally open contact and an output end connected between the power input end and the anti-reverse component, and is used for absorbing the transient pulse energy of the anti-reverse component and releasing to the power input end;

[0011] The back electromotive force release component has one end connected to the common terminal of the absorbing component and the anti-reverse component, and the other end is grounded or connected to the transient impact energy storage component;

[0012] The power supply component is arranged between the back electromotive force absorbing component and the power output end, and is used for generating power for the anti-reverse state switching component when there is a reverse electromotive force in the circuit.

[0013] Further, the anti-reverse component includes a diode or a unidirectional thyristor, the anode of the diode or the unidirectional thyristor is connected to the power input end, and the control end of the unidirectional thyristor is connected to the power supply component.

[0014] Further, the anti-reverse state switching component includes a relay, the relay is a normally closed relay, the common moving contact pin and the normally closed contact pin of the relay are connected to two ends of the anti-reverse component respectively, the normally open contact pin of the relay is connected to the transient impact energy storage component, and the coil pin of the relay is connected to the power supply component.

[0015] Further, the transient impact energy storage component includes an energy storage capacitor and an anti-reverse diode, the anode of the anti-reverse diode and the energy storage capacitor are connected to the normally open contact of the anti-reverse state switching component, and the cathode of the anti-reverse diode is connected between the power input end and the anti-reverse component.

[0016] Further, the absorbing component includes a first electrolytic capacitor, the positive pole of the first electrolytic capacitor is connected to the anti-reverse component, and the negative pole is grounded.

[0017] Further, the back electromotive force release component includes a switch and a fourth resistor, one electrode end of the switch is connected to each end of the anti-reverse component respectively, the other electrode end of the switch is connected in series with the fourth resistor, the other end of the fourth resistor is grounded, and the control end of the switch is connected to the power input end.

[0018] Further, the back electromotive force release component comprises a switch element, one electrode end and a control end of the switch element are connected with the far-from-ground end of the back electromotive force absorption component, and the other electrode end of the switch element is connected with the transient impact energy storage component.

[0019] Further, the back electromotive force release component comprises a unidirectional thyristor and a fourth resistor, the anode of the unidirectional thyristor is connected with the far-from-ground end of the back electromotive force absorption component, and the cathode of the unidirectional thyristor is grounded through the fourth resistor; the back electromotive force release component further comprises a ninth resistor and a sixth capacitor which are connected in series and then connected in parallel between the two ends of the back electromotive force absorption component, and the common end of the ninth resistor and the sixth capacitor is connected with the control end of the unidirectional thyristor.

[0020] Further, the power supply component comprises a transformer, the primary coil of the transformer is connected in series between the energy storage component and the power supply output end; one end of the secondary coil of the transformer is connected in series with a fifth diode, the cathode of the fifth diode is the positive output end of the power supply component, the other end of the secondary coil of the transformer is connected in series with a voltage stabilizing diode, the cathode of the voltage stabilizing diode is the negative output end of the power supply component; the anode end of the voltage stabilizing diode is grounded; and the positive output end and the negative output end of the power supply component are further connected with an electrolytic capacitor.

[0021] Further, the circuit further comprises a working indication component, the working indication component comprises a current-limiting resistor and a light-emitting diode which are connected in series, the cathode of the light-emitting diode is grounded, and the other end of the current-limiting resistor is connected between the back electromotive force absorption component and the power supply component.

[0022] Compared with the prior art, the technical scheme and beneficial effects of the utility model are as follows:

[0023] (1) The anti-back component is used for preventing the back electromotive force generated by the load from impacting the power supply, the absorption component absorbs the back electromotive force generated by the load, and the release component releases the back electromotive force in the absorption component, thereby playing a good protection role on the power supply. Meanwhile, when there is no back electromotive force or the back electromotive force is smaller than the output voltage of the power supply in the circuit, the anti-back component is short-circuited to reduce the energy consumption of the anti-back component. Meanwhile, the transient impact energy storage component stores the transient large energy signal of the anti-back component, and when there is no back electromotive force, the transient impact energy storage component releases the stored energy into the main circuit, so that the sudden energy interference in the protection process is effectively inhibited, and the energy is avoided from being wasted.

[0024] (2) The release component of the utility model, through the pressure difference between the base and the emitter, realizes the release to the reverse electromotive force, and simultaneously through the light emitting diode, the release process is directly indicated.

[0025] (3) The power supply component of the utility model generates the power supply of the anti-reverse state switching component through the induction of the reverse electromotive force, and the working state of the anti-reverse state switching component is accurately controlled. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a principle block diagram of the anti-reverse electromotive force circuit provided by the utility model embodiment;

[0027] Figure 2 It is a circuit principle diagram of the anti-reverse electromotive force circuit provided by the utility model embodiment;

[0028] Figure 3 It is still another circuit principle diagram of the anti-reverse electromotive force circuit provided by the utility model embodiment.

[0029] ILLUSTRATION:

[0030] Power input end -10;Power output end -20;Anti-reverse component -30;Reverse electromotive force absorption component -40;Reverse electromotive force release component -50;Anti-reverse state switching component -60;Power supply component -70;Working indication component -80;Energy storage component -90. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the utility model embodiment clearer, the technical scheme in the utility model embodiment will be described clearly and completely in the following with reference to the drawings in the utility model embodiment, obviously, the described embodiment is a part of the embodiment of the utility model, rather than all the embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model, and are not used to limit the utility model. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the utility model.

[0032] Referring to Figures 1 to 3A reverse electromotive force circuit includes a power input terminal 10, a power output terminal 20, a reverse prevention component 30, a reverse electromotive force absorption component 40, a reverse electromotive force release component 50, a reverse prevention state switching component 60, a power supply component 70, and an energy storage component 90. The power input terminal 10 is connected to a power source, and the power output terminal 20 is a final output terminal of the power source and supplies power to a load (not shown). The reverse prevention component 30 is connected in series between the power input terminal 10 and the power output terminal 20, and is used to prevent the reverse electromotive force generated by the load from impacting the power source. The reverse electromotive force absorption component 40 is connected between the reverse prevention component 30 and the power output terminal 20, and is grounded, and is used to absorb the reverse electromotive force generated by the load. The reverse electromotive force release component 50 is connected to one end of the reverse prevention component 30 away from the power input terminal 10 and is grounded at the other end, and is used to release the reverse electromotive force in the reverse electromotive force absorption component 40.

[0033] The reverse prevention state switching component 60 has two sets of common movable contacts, a normally closed contact, and a normally open contact. The common end and the normally closed contact of the reverse prevention state switching component 60 are connected to the two ends of the reverse prevention component 30, respectively. The input end of the transient impact energy storage component is connected to one of the normally open contacts, and the output end is connected between the power input terminal and the reverse prevention component, and is used to absorb the transient pulse energy of the reverse prevention component and release it to the main circuit. The input end of the reverse electromotive force auxiliary storage component is connected to the other normally open contact, and the output end is connected between the reverse electromotive force absorption component and the power output terminal, and is used to assist in absorbing the reverse electromotive force and releasing it to the main circuit. The reverse prevention state switching component 60 is in a normally closed state when it is not powered. The power supply component 70 is connected in series between the reverse electromotive force absorption component 40 and the power output terminal 20, and is used to supply power to the reverse prevention state switching component 60 when there is a reverse electromotive force in the circuit. That is, when the load does not generate a reverse electromotive force, the power supply component 70 does not supply power to the reverse prevention state switching component 60, and the reverse prevention state switching component 60 works in a normally closed state, thereby forming a short circuit between the two ends of the reverse prevention component 30, and thus avoiding the waste of energy caused by the reverse prevention component 30 being connected to the circuit when the power source is working normally for a long time (without being impacted by a reverse electromotive force). When the load generates a large reverse electromotive force, the power supply component 70 supplies power to the reverse prevention state switching component 60, and the reverse prevention state switching component 60 switches to the normally open contact, so that the transient impact energy storage component and the reverse electromotive force auxiliary storage component are connected to the circuit, and are used to absorb the transient impact energy and the reverse electromotive force, respectively, and release the absorbed energy to the main circuit after the circuit returns to the forward direction, thereby avoiding the waste of energy.

[0034] Continuing to refer to Figure 1In the embodiment, the anti-reverse component 30 adopts a unidirectional thyristor Q1. The anode of the unidirectional thyristor Q1 is connected with the power input terminal 10, the cathode of the unidirectional thyristor Q1 is connected with the positive pole of the electrolytic capacitor C1, and the control terminal of the unidirectional thyristor Q1 is connected with the power supply component 70. When a reverse electromotive force is generated in the circuit, the unidirectional thyristor Q1 is turned on in the forward direction.

[0035] In another embodiment, the anti-reverse component 30 can also include a diode D1, and the anode of the diode D1 is connected with the power input terminal 10.

[0036] The reverse electromotive force absorption component 40 includes an electrolytic capacitor C1, and the positive pole of the electrolytic capacitor C1 is connected with the cathode of the unidirectional thyristor Q1, and the negative pole of the electrolytic capacitor C1 is grounded.

[0037] The reverse electromotive force release component 50 includes a unidirectional thyristor Q2 and a fourth resistor R4. The anode of the unidirectional thyristor Q2 is connected with the electrolytic capacitor C1 away from the ground, and the cathode of the unidirectional thyristor Q2 is grounded through the resistor R4. The reverse electromotive force release component 50 further includes a resistor R9, a voltage stabilizing diode ZD2 and an electrolytic capacitor C6 which are connected in series and then connected in parallel between the two poles of the electrolytic capacitor C1. The anode of the voltage stabilizing diode ZD2 and the positive pole of the electrolytic capacitor C6 are connected with the control terminal of the unidirectional thyristor Q2, and the negative pole of the electrolytic capacitor C6 is grounded. In the embodiment, the reverse electromotive force release component 50 further includes a current-limiting resistor R5 and a light-emitting diode D3 which are connected in parallel between the two poles of the resistor R4, and the cathode of the light-emitting diode D3 is grounded.

[0038] When the reverse electromotive force in the electrolytic capacitor C1 is greater than the voltage parameter of the voltage stabilizing diode ZD2, the voltage stabilizing diode ZD2 is turned on to charge the electrolytic capacitor C6, and the electrolytic capacitor C6 provides a starting current signal to the control terminal of the unidirectional thyristor Q2, so that the AK terminal of the unidirectional thyristor Q2 can be turned on, and then the electromotive force energy stored in the C1 is released to the GND through the unidirectional thyristor Q2 and the resistor R4. The light-emitting diode D3 connected in parallel between the two poles of the resistor R4 performs brightness indication from bright to dark during the release process. The voltage parameter of the voltage stabilizing diode ZD2 is the same as the input voltage.

[0039] When no reverse electromotive force is generated, or the reverse electromotive force is less than the power output voltage, the anode voltage of the diode D1 is always greater than the voltage of the cathode, the diode D1 is turned on in the forward direction, the electrolytic capacitor C1 functions as an energy storage filter, and the light-emitting diode D2 connected in parallel between the two poles of the electrolytic capacitor C1 is bright, indicating that the power supply is in normal working. At this time, the unidirectional thyristor Q1 is not turned on, so the light-emitting diode D3 is not bright.

[0040] Continuing to refer to Figure 2 and Figure 3, the anti-reverse state switching component 60 includes a relay KA, the relay KA is a normally closed relay, the relay KA has at least two groups of common moving contact, normally closed contact and normally open contact, in order to facilitate representation, in the embodiment, the first group of common moving contact is recorded as 1 foot, the first group of normally closed contact is 2 foot, the first group of normally open contact is 3 foot, the second group of common moving contact is 4 foot, the second group of normally closed contact is 5 foot, and the second group of normally open contact is 6 foot.The common moving contact 1 foot of the relay is connected between the anti-reverse component 30 and the power input end 10, and the normally closed contact 2 foot of the relay is connected to the other end of the anti-reverse component 30.

[0041] When there is no reverse electromotive force in the power supply circuit, the power supply component does not generate power, and the relay KA remains in the normally closed state, thereby short-circuiting the diode D1, thereby avoiding the diode D1 from generating energy consumption when the power supply is working normally for a long time. Or the anode of the unidirectional thyristor Q1 is short-circuited, thereby avoiding the unidirectional thyristor Q1 from not conducting and causing the main circuit to fail to work when the power supply is working normally for a long time (a large enough reverse electromotive force causes the power supply component to generate power to supply the unidirectional thyristor Q1).

[0042] The common moving contact 4 foot of the relay is connected to the normally closed contact 2 foot, and the normally closed contact 5 foot of the relay is connected to the common moving contact 1 foot. In the normally closed state, the common moving contact 4 foot and the normally closed contact 5 foot also short-circuit the anti-reverse component 30.

[0043] The normally open contact 3 foot of the relay is connected to the transient impact energy storage component, and the normally open contact 6 foot of the relay is connected to the reverse electromotive force auxiliary storage component. The relay coil pin is connected to the power supply component 70.

[0044] Continuing to refer to Figure 2 The transient impact energy storage component includes an energy storage capacitor C4 and a diode D4. The anode of the diode D4 and the normally open contact 3 foot of the relay are connected, and the cathode of the diode D4 is connected between the power input end 10 and the anti-reverse component 30, that is, connected to the main circuit.

[0045] The electromotive force auxiliary storage component includes an energy storage capacitor C7, a diode D10 and a diode D9. The anode of the diode D10 is connected to the normally open contact 6 foot of the relay, the common end of the anodes of the diode D10 and the diode D9 is connected to the cathode of the diode D10, and the cathode of the diode D9 is connected between the reverse electromotive force absorption component 40 and the power supply component 70.

[0046] When there is a reverse electromotive force in the power supply circuit, the power supply component 70 generates power, and the relay KA switches to the normally open contact conduction. The anode of the diode D1 or the thyristor Q1 is connected to the transient impact energy storage component, and the cathode of the diode D1 or the thyristor Q1 is connected to the reverse electromotive force auxiliary storage component.

[0047] When the reverse electromotive force exists in the power supply circuit, the anode of the diode D1 or the thyristor Q1 will also be impacted by a node impulse due to the cathode voltage being greater than the anode voltage, which causes the energy to be not transferred to the cathode instantaneously. The impulse is a transient large energy interference signal, which will be temporarily stored in the energy storage capacitor C4 (at this time, the relay has been actuated, and the relay switch has been switched to the normally open contact 3 and the contact 6). When the reverse electromotive force disappears, the normally closed contact of the relay KA is restored to be conductive, and at this time, the energy temporarily stored in the energy storage capacitor C4 is conducted to the Vin+ output branch through the diode D4 again, so that the sudden energy interference in the protection process is effectively suppressed, and meanwhile, the energy is avoided from being wasted. The diode D4 uses the unidirectional conduction characteristic of the diode to effectively isolate the energy storage capacitor C4 from being charged when there is no reverse electromotive force, so that the energy storage capacitor C4 is only prepared for absorbing the interference of the anode of the diode D1 or the thyristor Q1 when the reverse electromotive force exists.

[0048] When the reverse electromotive force exists in the power supply circuit, the electrolytic capacitor C1 mainly absorbs and stores energy, and meanwhile, the reverse electromotive force at the K point is conducted to the normally open contact 6 through the common movable contact 4, and then is absorbed by the energy storage capacitor C7 through the diode D10. When the system recovers to the state without the reverse electromotive force, the temporarily stored energy in the energy storage capacitor C7 is released to the output main loop through the diode D9, so that the reverse electromotive force auxiliary storage component is used to increase the reverse electromotive force, and the energy is better dissipated by the device than the way of being completely absorbed and consumed by the electrolytic capacitor C1, because part of the reverse electromotive force energy can be stored and utilized when the circuit system recovers to the normal state.

[0049] The power supply component 70 includes a transformer T2, and the primary coil T2-1 of the transformer is connected in series between the current-limiting resistor R2 and the power supply output end 20. One end of the secondary coil T2-2 of the transformer is connected in series with the diode D5, the cathode of the diode D5 being the positive output end Vstart+ of the power supply component 70, and the other end of the secondary coil T2-2 of the transformer is connected in series with the voltage stabilizing diode TVS, the cathode of the voltage stabilizing diode TVS being the negative output end Vstart- of the power supply component 70; and the anode of the voltage stabilizing diode TVS is grounded. The positive output end Vstart+ and the negative output end Vstart- of the power supply component are also connected with the electrolytic capacitor C3.

[0050] When the direction electromotive force is greater than the power supply output voltage, the secondary coil T2-2 of the transformer will induce a reverse voltage on the primary coil T2-1 of the transformer to generate a power supply voltage, which drives the relay KA to actuate. When the reverse electromotive force reaches the protection threshold, the secondary coil T2-2 induces the electromotive force voltage on the primary coil T2-1 to reach the voltage required for the relay KA to switch and actuate. By selecting the transient voltage suppression diode TVS, the protection threshold of the circuit is set.

[0051] The power supply assembly 70 further comprises a resistor R7 connected with the cathode of the diode D5, i.e. the positive output terminal Vstart+ of the power supply assembly 70, and the other end of the resistor R7 is connected with the control end of the unidirectional thyristor Q1, and the end of the resistor R7 away from the unidirectional thyristor Q1 is further connected with a voltage stabilizing diode ZD1. The voltage stabilizing diode ZD1 can stabilize the positive output terminal Vstart+ of the power supply assembly 70 and the voltage of the control end of the unidirectional thyristor Q1.

[0052] The circuit further comprises an energy storage assembly, which comprises an electrolytic capacitor C5, the positive pole of the electrolytic capacitor C5 is arranged between the current limiting resistor R2 and the transformer T2, and the negative pole of the electrolytic capacitor C5 is grounded. The electrolytic capacitor C5 can enhance the delay of the reverse charging voltage to reach the moving contact of the relay KA to switch from the normally closed contact to the normally open contact, so that the diode D1 or the unidirectional thyristor Q1 is normally connected to the circuit.

[0053] The above description shows and describes the preferred embodiments of the present application, and it should be understood that the present application is not limited to the forms disclosed herein, and should not be considered as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the present application conceived herein, through the above teaching or related technical or knowledge. Any modification and change made by those skilled in the art without departing from the spirit and scope of the present application shall be within the protection scope of the claims of the present application.

Claims

1. A circuit for preventing back electromotive force, characterized in that, include: The reverse protection component is connected in series between the power input terminal and the power output terminal; A back EMF absorption component, one end of which is connected between the anti-reverse component and the power output terminal, and the other end is grounded; The anti-reverse state switching component has at least two sets of common moving contacts, normally closed contacts, and normally open contacts. The common moving contacts and normally closed contacts are respectively connected to the two ends of the anti-reverse component. The anti-reverse state switching component is in the normally closed state when it is not powered on. An energy buffer component includes a transient impact energy buffer component and a back EMF auxiliary buffer component. The input terminal of the transient impact energy buffer component is connected to one of the normally open contacts, and the output terminal is connected between the power input terminal and the anti-reverse component. It is used to absorb the transient pulse energy of the anti-reverse component and release it to the main circuit. The input terminal of the back EMF auxiliary buffer component is connected to the other of the normally open contacts, and the output terminal is connected between the back EMF absorption component and the power output terminal. It is used to assist in absorbing the back EMF and releasing it to the main circuit. A back electromotive force release component, one end of which is connected to the common terminal of the absorption component and the anti-backflow component, and the other end of which is grounded or connected to the transient impact energy buffer component; A power supply component is disposed between the back electromotive force absorption component and the power output terminal, and is used to generate power to supply the anti-reverse state switching component when there is a back electromotive force in the circuit.

2. The anti-back EMF circuit according to claim 1, characterized in that, The anti-reverse component includes a diode or a unidirectional thyristor, the anode of which is connected to the power input terminal; the control terminal of which is connected to the power supply component.

3. The anti-back EMF circuit according to claim 1, characterized in that, The anti-reverse state switching component includes a relay. The first set of common moving contacts of the relay is connected between the anti-reverse component and the power input terminal. The first set of normally closed contacts of the relay is connected to the other end of the anti-reverse component. The first set of normally open contacts of the relay is connected to the transient impact energy buffer component. The second set of common moving contacts of the relay is connected to the first set of normally closed contacts, the second set of normally closed contacts of the relay is connected to the first set of common moving contacts, and the second set of normally open contacts of the relay is connected to the back electromotive force auxiliary buffer component. The relay is a normally closed relay; the relay coil pin is connected to the power supply component.

4. The anti-back EMF circuit according to claim 3, characterized in that, The transient impact energy buffer component includes a fourth energy storage capacitor and a fourth diode. The anode of the fourth diode and the fourth energy storage capacitor are connected to the first set of normally open contacts of the relay, and the cathode of the fourth diode is connected between the power input terminal and the anti-reverse component.

5. The anti-back EMF circuit according to claim 3, characterized in that, The back EMF auxiliary buffer component includes a seventh energy storage capacitor, a tenth diode, and a ninth diode. The anode of the tenth diode is connected to the second set of normally open contacts of the relay. The common terminal of the anodes of the seventh energy storage capacitor and the ninth diode is connected to the cathode of the tenth diode. The cathode of the ninth diode is connected between the back EMF absorption component and the power supply component.

6. The anti-back EMF circuit according to claim 1, characterized in that, The back EMF absorption component includes a first electrolytic capacitor, the positive terminal of which is connected to the anti-reverse component, and its negative terminal is grounded.

7. The anti-back EMF circuit according to claim 1, characterized in that, The back EMF release component includes a unidirectional thyristor and a fourth resistor. The anode of the unidirectional thyristor is connected to the end of the back EMF absorption component away from the ground, and the cathode of the unidirectional thyristor is grounded through the fourth resistor. The back EMF release component also includes a ninth resistor, a Zener diode, and a sixth electrolytic capacitor connected in series and then in parallel across the back EMF absorption component. The common terminal of the anode of the Zener diode and the positive terminal of the sixth electrolytic capacitor is connected to the control terminal of the unidirectional thyristor, and the negative terminal of the sixth capacitor is grounded.

8. The anti-back EMF circuit according to claim 1, characterized in that, The power supply component includes a transformer, the primary winding of which is connected in series between the back EMF absorption component and the power output terminal; one end of the secondary winding of the transformer is connected in series with a fifth diode, the cathode of which is the positive output terminal of the power supply component; the other end of the secondary winding of the transformer is connected in series with a Zener diode, the cathode of which is the negative output terminal of the power supply component; the anode of the Zener diode is grounded; and an electrolytic capacitor is also connected between the positive and negative output terminals of the power supply component.

9. The anti-back EMF circuit according to claim 1, characterized in that, It also includes a working indicator component, which includes a current-limiting resistor and a light-emitting diode connected in series. The cathode of the light-emitting diode is grounded, and the other end of the current-limiting resistor is connected between the back electromotive force absorption component and the power supply component.

10. The anti-back EMF circuit according to claim 1, characterized in that, It also includes an energy storage component, one end of which is connected to the end of the power supply component away from the power output terminal, and the other end of which is grounded.

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