Anti-galloping signal loop protection device for charger

Abstract

The invention relates to the field of high-power chargers, and discloses a charger anti-galloping signal loop protection device which comprises an anti-galloping signal relay module A part, a reverse protection diode B part and a PTC recoverable fuse C. The anti-galloping signal relay module A part is composed of a relay K1, a fly-wheel diode D1, a current-limiting resistor R5 and a filter capacitor C2. The relay K1 comprises a control coil and a contact, and the diode D3 and the PTC resettable fuse are connected in series in an anti-galloping signal loop in the charger. The anti-galloping signal loop of the charger simultaneously uses the diode and the recoverable fuse for dual protection, reliable protection can be realized under the conditions of overcurrent, short circuit and reverse connection, and the recoverable fuse replaces a traditional fuse, so that the circuit can be repeatedly used and is higher in reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of high-power chargers, in particular to a charger anti-runaway signal circuit protection device. Background Art

[0002] With the continuous advancement of new energy technologies, more and more equipment, such as sweepers, aerial work platforms, and high-power power tools, have abandoned traditional fuel power sources and instead adopted new energy storage batteries as their primary power source. These energy storage batteries require high-power chargers to support their efficient operation, which places extremely high demands on the safety and reliability of the chargers to ensure that they can operate stably and safely in these complex environments.

[0003] Most chargers lack protection for the anti-runaway signal circuit within the charger. If the battery in the back-end device is reversely connected, the main output will be protected, but the anti-runaway signal circuit is easily damaged by reverse connection, causing a large reverse current to flow through the circuit, resulting in damage to the anti-runaway signal circuit and malfunctioning of the entire charger. This also results in unnecessary direct and indirect costs. Therefore, it is necessary to develop a charger anti-runaway signal circuit protection device to ensure the normal operation of the equipment and the safety of personnel. Summary of the Invention

[0004] In response to the deficiencies of the prior art, the present invention provides a charger anti-runaway signal circuit protection device, which solves the problem in the prior art that the anti-runaway signal circuit has no protection measures and is easily damaged by reverse connection, causing a large reverse current to flow into the circuit and thus causing abnormal operation of the entire charger.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: a charger anti-runaway signal circuit protection device, including an anti-runaway signal relay module part A, a reverse protection diode part B, and a PTC resettable fuse part C. The anti-runaway signal relay module part A is composed of a relay K1, a freewheeling diode D1, a current limiting resistor R5 and a filter capacitor C2. The relay K1 includes a control coil and contacts. The diode D3 and the PTC resettable fuse are connected in series in the anti-runaway signal circuit inside the charger.

[0006] By adopting the above technical solution, the circuit realizes the logical control of the anti-runaway signal through the relay module, uses the reverse protection diode to prevent damage due to reverse polarity, and combines with the PTC fuse to realize overcurrent protection. At the same time, the three are connected in series to form a signal loop, realizing multiple protections against overcurrent, short circuit and reverse connection. At the same time, the synergistic effect of the three can effectively avoid the risks of runaway and circuit burning, and is suitable for scenarios such as electric vehicles and robots that require safe disconnection of the power circuit.

[0007] Preferably, a freewheeling diode D1 and an RC buffer circuit are connected in parallel at both ends of the coil of the relay K1.

[0008] Preferably, the RC buffer circuit is composed of a current limiting resistor R5 and a filter capacitor C2 connected in series.

[0009] Preferably, one end of the filter capacitor C2 in the RC buffer circuit is connected to the resistor R5, and the other end is connected to SGND.

[0010] Preferably, the capacitor C7 is connected in parallel between the normally closed contact RelNC and SGND of the relay.

[0011] Preferably, the resistor R6 and the PTC resettable fuse are connected in parallel to form an overcurrent protection branch, and the resistor R6 and the PTC resettable fuse are connected in parallel and then in series in the signal loop.

[0012] Preferably, the anode of the diode D3 is connected to the positive electrode of the charger output terminal, and the cathode of the diode D3 is connected to the input terminal of the PTC restoreable fuse, thereby forming a polarity protection circuit to prevent reverse current.

[0013] Preferably, the output end of the PTC resettable fuse is connected to the common end RelCom of the relay K1.

[0014] Preferably, the output end of the PTC resettable fuse is connected to pin 1 of the Header2 interface P7 to transmit the anti-runaway signal to the load, forming a signal main loop.

[0015] Preferably, the switch contacts of the anti-runaway signal relay K1 are linked to the relay coil for control, the common terminal RelCOM of the relay K1 is linked to the normally closed contact RelNC for switching, and the pin 2 of the Header2 interface P7 is connected to the normally closed contact RelNC.

[0016] Working principle: When there is no mains power, the normally closed contact 4-3 of the anti-runaway signal relay is connected, and the working power supply circuit in the charger's back-end equipment system is connected, entering the pre-working state. A diode D3 and a PTC resettable fuse are connected in series in the charger's internal anti-runaway signal circuit. When the battery in the charger's back-end equipment is reversed, due to the unidirectional conduction property of diode D3, the large reverse current generated by the reverse battery in the back-end equipment system cannot pass through the charger's internal anti-runaway signal circuit, so the anti-runaway signal circuit will not be damaged by the large reverse current. In addition, when the internal circuit of the back-end equipment is short-circuited, the PTC resettable fuse in series in the anti-runaway signal circuit will operate, the circuit impedance will increase in a short time, and the large short-circuit current will be converted into a small current in a very short time. Flow, thereby also protecting the anti-runaway signal circuit, and will not be damaged due to the conduction of large forward current. When the anti-runaway circuit in the back-end equipment works normally, the PTC resettable fuse in the anti-runaway signal circuit in the charger can resume normal operation. When the coil is not energized, the common terminal RelCOM of relay K1 and the normally closed contact RelNC are closed, and the signal is transmitted to the load normally. At the same time, the circuit achieves double protection for the load through the coordination of relay hardware cut-off and PTC self-recovery current limiting, which not only ensures the reliable triggering of the anti-runaway function, but also resists overload / short circuit risks. The circuit protection device provides a safety protection system independent of the mains for the equipment through the triple mechanism of relay hardware cut-off, diode polarity protection, and PTC resettable fuse overcurrent limiting.

[0017] The present invention provides a charger anti-runaway signal circuit protection device, which has the following beneficial effects: 1. The present invention uses a diode and a resettable fuse for dual protection in the charger anti-runaway signal circuit, which can achieve reliable protection in the case of overcurrent, short circuit and reverse connection. The resettable fuse replaces the traditional fuse, making the circuit reusable and more reliable.

[0018] 2. The diode D3 used in the present invention has the characteristic of unidirectional flow. When there is a reverse voltage, the diode does not conduct, thereby restoring the fuse. When the current flowing through is too large, the resistance value becomes larger and the current becomes smaller, protecting the charger. When the normal current is restored, it returns to a low-resistance state and can be reused.

[0019] 3. The present invention has designed a circuit in which, when a short circuit occurs in the internal circuit of the back-end device, the resettable fuse connected in series with the anti-runaway signal circuit will operate, the circuit impedance will increase in a short time, and the high short-circuit current will become a low current in a very short time, thereby protecting the anti-runaway signal circuit from being damaged by the conduction of a large forward current.

[0020] 4. The circuit designed in the present invention can restore the normal operation of the anti-runaway circuit in the charger when the anti-runaway circuit in the back-end device works normally. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a circuit connection diagram of the present invention. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0023] Please see the attached Figure 1 An embodiment of the present invention provides a charger anti-runaway signal circuit protection device, comprising an anti-runaway signal relay module A, a reverse protection diode B, and a PTC resettable fuse C. The anti-runaway signal relay module A comprises a relay K1, a freewheeling diode D1, a current-limiting resistor R5, and a filter capacitor C2. The relay K1 includes a control coil and contacts. The diode D3 and the PTC resettable fuse are connected in series in the charger's internal anti-runaway signal circuit. Specifically, diode D3 is connected in series in the signal loop to prevent the charger or external circuit from reversely energizing the anti-runaway signal loop due to reverse power polarity, thereby preventing damage to components such as relays and loads due to reverse current, and protecting the internal circuit of the charger from reverse voltage shock. The PTC fuse can prevent relay contact erosion, line fire or load damage caused by excessive current. Compared with traditional fuses, manual replacement is not required, which improves system availability. In the anti-runaway scenario, if the circuit is overloaded before the relay contacts are disconnected, the PTC can limit the current in advance to reduce the burden on the relay contacts.

[0024] See attached Figure 1 , the two ends of the relay K1 coil are connected in parallel with a freewheeling diode D1 and an RC snubber circuit; Specifically, since the relay coil is an inductive load, it will generate reverse electromotive force when the power is off. The freewheeling diode D1 is connected in parallel to both ends of the relay K1 coil. When the relay coil is powered off, the reverse electromotive force generated by the coil is suppressed, preventing high voltage from breaking down the drive circuit components and protecting the control circuit. The RC snubber circuit can reduce the oscillation amplitude and frequency, reduce EMI radiation, and the RC snubber circuit can fine-tune the relay release time, which is suitable for scenarios with strict timing requirements. Therefore, the freewheeling diode D1 is responsible for low-voltage freewheeling, and the RC snubber circuit is responsible for high-frequency oscillation suppression, making the two complementary.

[0025] See attached Figure 1 , the RC snubber circuit is composed of a current limiting resistor R5 and a filter capacitor C2 in series; Specifically, the current-limiting resistor R5 can limit the coil current to prevent excessive current from burning the coil or driving components, while ensuring that the voltage across the coil meets the rated value. The filter capacitor C2 can filter out high-frequency interference in the power supply, stabilize the coil driving voltage, and avoid malfunction of the relay. The synergistic effect of resistor current limiting and capacitor energy storage can suppress the high-voltage spike of the reverse electromotive force generated when the relay coil K1 is powered off, protecting the drive circuit from transient voltage shocks.

[0026] See attached Figure 1 , one end of the filter capacitor C2 in the RC snubber circuit is connected to the resistor R5, and the other end is connected to SGND; Specifically, by connecting the other end of the filter capacitor C2 to SGND, a low-impedance discharge path can be provided for the high-frequency oscillation noise generated when the relay coil K1 is powered off. At the same time, the discharge current is limited by the resistor R5 to prevent transient energy from being reflected to the drive circuit.

[0027] See attached Figure 1 , capacitor C7 is connected in parallel between the relay normally closed contact RelNC and SGND; Specifically, the high-frequency arc noise generated by the mechanical action of the contacts can be filtered out by the parallel capacitor C7, thereby preventing the interference signal from being transmitted to the rear-end load circuit through the Header2.

[0028] See attached Figure 1 , the resistor R6 and the PTC resettable fuse are connected in series to form an overcurrent protection branch, and the resistor R6 and the PTC resettable fuse are connected in series in the signal loop; Specifically, resistor R6 is an anti-electromagnetic interference device that can prevent the electromagnetic interference between the terminal device and the charger through the overspeed signal line. It is connected in series with the PTC in the main circuit of the anti-overspeed signal. When the load is short-circuited or overloaded, such as when the current exceeds the PTC threshold, the resistance of the PTC resettable fuse increases sharply due to the self-heating effect, limiting the current to a safe level. Therefore, the resistor R6 and the PTC resettable fuse are connected in series in the signal circuit to form a composite branch that improves radiation interference and overcurrent protection. In addition, the impedance of the resistor R6 is greater than 100Ω@100MHZ, which can effectively deal with high-frequency interference.

[0029] See attached Figure 1 The anode of diode D3 is connected to the positive terminal of the charger output, and the cathode of diode D3 is connected to the input terminal of the PTC restoreable fuse, thereby forming a polarity protection circuit to prevent reverse current; Specifically, the anode of diode D3 is connected to the positive electrode of the charger output terminal. If the power polarity is reversed, such as when the positive and negative poles of the charger are connected incorrectly, the reverse current is blocked due to the unidirectional conductivity of diode D3, and the loop current between the subsequent circuit and the reverse-connected power supply approaches zero, thereby preventing the subsequent circuit from suffering overvoltage damage due to direct connection to the reverse-polarity power supply. The unidirectional conductivity of diode D3 and the overcurrent protection characteristics of the PTC provide protection in the event of forward current overload, further enhancing circuit safety and achieving dual protection against power polarity errors and overload.

[0030] See attached Figure 1 , the output end of the PTC resettable fuse is connected to the common end RelCom of relay K1; Specifically, the PTC is connected in series in the main signal circuit before the RelCOM to protect the entire circuit from overload damage.

[0031] See attached Figure 1 , the output end of the PTC resettable fuse is connected to pin 1 of the Header2 interface P7 to transmit the anti-runaway signal to the load, forming the signal main loop; Specifically, when the relay K1 is not actuated, the COM-NC contacts are closed, and the signal forms a closed loop through the NC contacts. When the relay is actuated, COM-NC is disconnected, forcibly cutting off the signal.

[0032] See attached Figure 1 , the switch contacts of the anti-runaway signal relay K1 form a linkage control with the relay coil, the common terminal RelCOM of the relay K1 is linked to the normally closed contact RelNC, and the pin 2 of the Header2 interface P7 is connected to the normally closed contact RelNC; Specifically, when the coil of relay K1 is not energized, its common terminal RelCOM and the normally closed contact RelNC are connected by default, so that pin 1 and pin 2 of Header2 interface P7 form a closed loop, and the RelCOM connection terminal and the RelNC connection terminal are connected, allowing the anti-runaway signal or current to be transmitted to the load normally, ensuring that the device is enabled by default in battery mode. When the runaway protection mechanism is triggered, the coil is energized to drive the RelCOM connection terminal and the RelNC connection terminal to disconnect, forcibly cutting off the signal path between pin 1 and pin 2, disabling the load and shutting down, thereby achieving anti-runaway protection. In this process, the overcurrent can be limited by the PTC resettable fuse to provide double protection.

[0033] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A charger anti-runaway signal circuit protection device, comprising an anti-runaway signal relay module (A), a reverse protection diode (B), and a PTC resettable fuse (C), characterized in that: The anti-runaway signal relay module A is composed of a relay K1, a freewheeling diode D1, a current-limiting resistor R5 and a filter capacitor C2. The relay K1 includes a control coil and contacts. The diode D3 and the PTC resettable fuse are connected in series in the anti-runaway signal circuit inside the charger.

2. The charger anti-runaway signal circuit protection device according to claim 1, characterized in that: A freewheeling diode D1 and an RC buffer circuit are connected in parallel to both ends of the relay K1 coil.

3. The charger anti-runaway signal circuit protection device according to claim 2, characterized in that: The RC buffer circuit is composed of a current limiting resistor R5 and a filter capacitor C2 connected in series.

4. The charger anti-runaway signal circuit protection device according to claim 1, characterized in that: One end of the filter capacitor C2 in the RC buffer circuit is connected to the resistor R5 , and the other end is connected to SGND.

5. The charger anti-runaway signal circuit protection device according to claim 1, characterized in that: The capacitor C7 is connected in parallel between the normally closed contact RelNC and SGND of the relay.

6. The charger anti-runaway signal circuit protection device according to claim 1, characterized in that: The resistor R6 and the PTC resettable fuse are connected in parallel to form an overcurrent protection branch. The resistor R6 and the PTC resettable fuse are connected in parallel and then in series in the signal loop.

7. The charger anti-runaway signal circuit protection device according to claim 1, characterized in that: The anode of the diode D3 is connected to the positive electrode of the charger output terminal, and the cathode of the diode D3 is connected to the input terminal of the PTC restoreable fuse, thereby forming a polarity protection circuit to prevent reverse current.

8. The charger anti-runaway signal circuit protection device according to claim 1, characterized in that: The output end of the PTC resettable fuse is connected to the common end RelCom of the relay K1.

9. The charger anti-runaway signal circuit protection device according to claim 1, characterized in that: The output end of the PTC resettable fuse is connected to pin 1 of the Header2 interface P7 to transmit the anti-runaway signal to the load, forming a signal main loop.

10. The charger anti-runaway signal circuit protection device according to claim 1, characterized in that: The switch contacts of the anti-runaway signal relay K1 form a linkage control with the relay coil, the common terminal RelCOM of the relay K1 is linked to the normally closed contact RelNC and the pin 2 of the Header2 interface P7 is connected to the normally closed contact RelNC.

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