Self-protection circuit suitable for energy storage pre-charging loop
By introducing temperature switches and anti-reverse diodes into the energy storage pre-charge circuit, the short circuit and reverse connection problems of the pre-charge circuit are solved, and the self-protection function is realized to prevent device damage and explosion, ensuring circuit safety and reliability.
Patent Information
- Application Number
- CN202421507952.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-28
- Publication Date
- 2025-07-25
- Estimated Expiration
- 2034-06-28
AI Technical Summary
The pre-charge circuit of the energy storage system lacks short-circuit protection devices, and there is a problem that external short circuit damages the main circuit fuse and the pre-charge circuit lacks self-protection capabilities. The pre-charge circuit may heat up or overload failure when the main relay is not closed.
A self-protection circuit is designed, including a temperature switch and an anti-reverse diode. The temperature switch is used to monitor the temperature of the precharge resistor and disconnect the precharge relay when the action threshold is reached to achieve temperature protection; the anti-reverse diode prevents the load end from being reversed; and the circuit is disconnected by the precharge fuse when the load is short-circuited to achieve short-circuit protection.
It realizes self-protection of the precharge loop when the external load is shorted or the load is reversed, preventing device damage and explosion, and ensuring safe and reliable operation of the circuit.
Smart Images
Figure CN223156690U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a self - protection circuit applicable to an energy storage pre - charge circuit. Background Art
[0002] With the growing energy storage industry, large - scale power station - level energy storage systems are all distributed in remote areas. If components in the system are damaged during operation, personnel need to be sent to the site to handle the faults, resulting in a straight - line increase in after - sales operation costs. When the energy storage system powers on at high voltage, if the negative main contactor and the positive main contactor are directly closed, at this time, due to the very small bus line resistance, which can be basically ignored, it is equivalent to directly short - circuiting the positive and negative poles of the battery system, and an instantaneous large current will be generated in the circuit, damaging the high - voltage circuit and high - voltage components. Therefore, the pre - charge circuit is an indispensable part of the energy storage system. The pre - charge circuit is composed of a pre - charge relay and a pre - charge resistor. Its working principle is that when powering on at high voltage, first close the negative main contactor and then close the pre - charge relay. When the high voltage passes through the main contact of the pre - charge relay first, and then passes through the pre - charge resistor for current limiting and then charges the bus load capacitor until the bus capacitor is charged to △V≤VB*10% (△V: the voltage on the bus capacitor, VB: the battery system voltage), close the positive contactor. Finally, the pre - charge circuit disconnects the pre - charge relay, and at this time, the pre - charge circuit exits, completing the entire pre - charge process. From the components of the pre - charge circuit, the pre - charge circuit mainly has the following defects:
[0003] 1) The pre - charge circuit lacks short - circuit protection devices. External short - circuits will cause the pre - charge circuit to fail and damage the main - circuit fuse at the same time;
[0004] 2) The pre - charge circuit lacks self - protection ability. When there is an error in the program logic and the main - circuit relay is not closed, the pre - charge circuit keeps working, causing the pre - charge resistor to heat up. As the working time increases, the resistance decreases and the current - limiting ability decreases, resulting in problems such as smoking and explosion;
[0005] 3) When the main relay is not closed, the pre - charge circuit acts as the main relay function and directly drives the load, resulting in the overload failure of the pre - charge relay. Content of the Utility Model
[0006] The purpose of the utility model is to overcome the deficiencies of the prior art. Without changing the traditional pre - charge method, the utility model proposes a self - protection circuit applicable to an energy storage pre - charge circuit, which can realize the self - protection of the pre - charge circuit when an external load is short - circuited during the pre - charge action of the pre - charge circuit; it can directly drive the load when the closing of the positive main relay fails, protecting the devices of the pre - charge circuit from damage and explosion.
[0007] The object of the present utility model is achieved through the following technical solutions: A self - protection circuit applicable to an energy storage pre - charge circuit, comprising a main circuit, a pre - charge circuit, and a drive circuit; the main circuit includes an energy storage power supply, a negative - pole relay K1, a positive - pole relay K2, and a main - circuit fuse F1; the pre - charge circuit includes a pre - charge self - recovering fuse F2, a pre - charge relay K3, a pre - charge resistor R1, and an anti - reverse diode D2; the drive circuit includes resistors R2 and R3, capacitors C1 and C2, a diode D1, a triode Q1, and a temperature switch S1;
[0008] The negative pole of the energy storage power supply is connected to the negative - pole relay K1, and the positive pole is sequentially connected to the main - circuit fuse F1 and the positive - pole relay K2; the pre - charge self - recovering fuse F2 is sequentially connected in series with the pre - charge relay K3, the pre - charge resistor R1, and the anti - reverse diode D2, and the series circuit is connected in parallel across both ends of the positive - pole relay K2;
[0009] Both ends of the control coil of the pre - charge relay K3 are respectively connected to the positive and negative poles of the diode D1; one end of the resistor R2 is connected to the externally input control signal P1, and the other end is respectively connected to the resistor R3 and the base of the triode Q1, and the other end of the resistor R3 is grounded; the collector of the triode Q1 is respectively connected to one end of the control coil of the pre - charge relay K3 and the positive pole of the diode D1, and the emitter is grounded; the negative pole of the diode D1 and the other end of the control coil of the relay K3 are both connected to the power supply VCC through the temperature switch S1; the capacitors C1 and C2 are connected in parallel, and one end of the parallel circuit is connected between the negative pole of the diode D1 and the temperature switch S1, and the other end is grounded.
[0010] The temperature switch S1 and the pre - charge resistor R1 are attached together through thermal conductive grease.
[0011] The positive pole of the anti - reverse diode D2 is connected to the pre - charge resistor R1, and the negative pole is connected to the positive - pole relay K2.
[0012] The beneficial effects of the present utility model are as follows: The present utility model proposes a self - protection circuit applicable to an energy storage pre - charge circuit without changing the traditional pre - charge method, which can realize the self - protection of the pre - charge circuit when an external load is short - circuited during the pre - charge operation of the pre - charge circuit. After the positive - pole main relay fails to close (the main relay is in the open state), the pre - charge circuit can directly supply power to the load circuit, causing the temperature of the pre - charge resistor R1 to rise rapidly. When the temperature reaches the action threshold of the temperature switch, the temperature switch S1 disconnects, thereby cutting off the drive power supply of the pre - charge relay, and the pre - charge relay disconnects, thus protecting the devices in the pre - charge circuit from damage and explosion. When the positive and negative poles at the load end of the main circuit of the present utility model are reversely connected, the pre - charge circuit can realize anti - reverse - connection self - protection. Description of the Drawings
[0013] Figure 1 It is a circuit diagram of the self - protection circuit applicable to the energy storage pre - charge circuit of the present utility model. Detailed implementation mode
[0014] The technical solution of the present utility model will be further described below with reference to the accompanying drawings.
[0015] As Figure 1 shown, a self - protection circuit applicable to an energy storage pre - charge circuit of the present utility model includes a main circuit, a pre - charge circuit and a drive circuit; the main circuit includes an energy storage power supply, a negative - pole relay K1, a positive - pole relay K2 (the coil parts of K1 and K2 are omitted in the figure), and a main - circuit fuse F1; the pre - charge circuit includes a pre - charge self - reset fuse F2, a pre - charge relay K3, a pre - charge resistor R1 and an anti - reverse diode D2; the drive circuit includes resistors R2 and R3, capacitors C1 and C2, a diode D1, a triode Q1, and a temperature switch S1;
[0016] The negative pole of the energy storage power supply is connected to the negative - pole relay K1, and the positive pole is sequentially connected to the main - circuit fuse F1 and the positive - pole relay K2; the pre - charge self - reset fuse F2 is sequentially connected in series with the pre - charge relay K3, the pre - charge resistor R1 and the anti - reverse diode D2, and the series circuit is connected in parallel across both ends of the positive - pole relay K2;
[0017] Both ends of the control coil of the pre - charge relay K3 are respectively connected to the positive and negative poles of the diode D1; one end of the resistor R2 is connected to the externally input control signal P1, and the other end is respectively connected to the resistor R3 and the base of the triode Q1, and the other end of the resistor R3 is grounded; the collector of the triode Q1 is respectively connected to one end of the control coil of the pre - charge relay K3 and the positive pole of the diode D1, and the emitter is grounded; the negative pole of the diode D1 and the other end of the control coil of the relay K3 are both connected to the power supply VCC through the temperature switch S1; the capacitors C1 and C2 are connected in parallel, and one end of the parallel circuit is connected between the negative pole of the diode D1 and the temperature switch S1, and the other end is grounded.
[0018] The normal working principle of the pre - charge circuit is as follows: the control signal P1 is divided by the resistors R2 and R2 to control the conduction of the triode Q1. At this time, the pre - charge relay K3 closes for pre - charge operation, and the pre - charge power supply realizes the pre - charge function through the main - circuit fuse F1, the pre - charge fuse F2, the pre - charge resistor R1 and the diode D2.
[0019] The temperature switch S1 and the pre - charge resistor R1 are attached together through thermal conductive grease. This enables the circuit to have a temperature - protection function: the temperature switch S1 is in a closed state by default, and it is attached to the pre - charge resistor R1 through thermal conductive grease. When the pre - charge circuit is in a continuous working state, the pre - charge resistor R1 generates heat, and its heat is conducted to the temperature switch S1 through the thermal conductive grease. When the temperature switch S1 detects that the temperature reaches its operating range, the temperature switch S1 acts. At this time, the control coil of the pre - charge relay K3 loses power, so that the pre - charge relay K3 disconnects, and the pre - charge circuit stops working. Therefore, the pre - charge circuit realizes the self - protection function of temperature monitoring.
[0020] The positive electrode of the anti-reverse diode D2 is connected to the pre-charge resistor R1, and the negative electrode is connected to the positive electrode relay K2. This enables the circuit to have an anti-reverse connection protection function: when the load terminals BAT+ and BAT- are connected reversely, the pre-charge current passes through the anti-reverse diode D2 and then connects to BAT-. At this time, the polarity of the capacitor on the BAT+ and BAT- bus is opposite to the polarity of the pre-charge voltage, and the diode D2 has unidirectional conductivity, so a complete pre-charge loop cannot be formed, thus realizing the self anti-reverse connection protection function of the pre-charge loop after the load is reversely connected.
[0021] The circuit of the present utility model has a short-circuit protection function: when there is an abnormal short-circuit fault at the load terminal, the pre-charge relay K3 closes, and the pre-charge loop starts to work. Due to the abnormal short-circuit fault at the load terminal, the load short-circuit current is extremely large, triggering the pre-charge fuse F2 to act, and the pre-charge loop is disconnected and loses the pre-charge function, realizing the self-protection of the pre-charge loop when the load is short-circuited.
[0022] Those of ordinary skill in the art will realize that the embodiments described herein are for helping the reader understand the principles of the present utility model, and it should be understood that the protection scope of the present utility model is not limited to such specific statements and embodiments. Those of ordinary skill in the art can make various other specific deformations and combinations that do not depart from the essence of the present utility model based on these technical revelations disclosed in the present utility model, and these deformations and combinations are still within the protection scope of the present utility model.
Claims
1. A self - protection circuit applicable to an energy storage pre - charge circuit, characterized in that, It includes a main circuit, a pre-charge circuit and a drive circuit; the main circuit includes an energy storage power supply, a negative relay K1, a positive relay K2 and a main circuit fuse F1; the pre-charge circuit includes a pre-charge self-resetting fuse F2, a pre-charge relay K3, a pre-charge resistor R1 and an anti-reverse diode D2; the drive circuit includes resistors R2 and R3, capacitors C1 and C2, a diode D1, a triode Q1, and a temperature switch S1; The negative pole of the energy storage power supply is connected to the negative relay K1, and the positive pole is sequentially connected to the main circuit fuse F1 and the positive relay K2; the pre-charge self-resetting fuse F2 is sequentially connected in series with the pre-charge relay K3, the pre-charge resistor R1 and the anti-reverse diode D2, and the series circuit is connected in parallel across both ends of the positive relay K2; Both ends of the control coil of the pre-charge relay K3 are respectively connected to the positive and negative poles of the diode D1; one end of the resistor R2 is connected to the externally input control signal P1, and the other end is respectively connected to the resistor R3 and the base of the triode Q1, and the other end of the resistor R3 is grounded; the collector of the triode Q1 is respectively connected to one end of the control coil of the pre-charge relay K3 and the positive pole of the diode D1, and the emitter is grounded; the negative pole of the diode D1 and the other end of the control coil of the relay K3 are both connected to the power supply VCC through the temperature switch S1; the capacitors C1 and C2 are connected in parallel, and one end of the parallel circuit is connected between the negative pole of the diode D1 and the temperature switch S1, and the other end is grounded.
2. The self - protection circuit applicable to the energy storage pre - charge circuit according to claim 1, wherein, The temperature switch S1 and the pre-charge resistor R1 are attached together with thermal grease.
3. The self - protection circuit applicable to the energy storage pre - charge circuit according to claim 1, wherein, The positive pole of the anti-reverse diode D2 is connected to the pre-charge resistor R1, and the negative pole is connected to the positive relay K2.