Novel switch switching control circuit suitable for insulation detection of energy storage battery

Abstract

The utility model discloses a novel switch switching control circuit suitable for energy storage battery insulation detection, comprising an energy storage battery insulation detection circuit and a relay driving control circuit, the energy storage battery insulation detection circuit comprises three relay switch circuits; the relay driving control circuit comprises a control IC, a level conversion chip and a driving circuit, two driving control signal output interfaces of the control IC are electrically connected with the level conversion chip, two driving signal output interfaces of the level conversion chip are directly and electrically connected with the driving circuit, and the driving circuit is electrically connected with the level conversion chip. The two driving signal output interfaces are respectively connected with two input ends of the common cathode diode D1, and the output end of the common cathode diode D1 is electrically connected with the driving circuit; the drive circuit is electrically connected with the three relay switch circuits. According to the utility model, the three relays are driven and controlled through the two driving signals, the circuit structure is simplified, and a protection design is added at the driving control side to carry out isolation protection on the control IC.

Description

Technical Field

[0001] This utility model relates to the field of switch switching control circuit technology, and in particular to a novel switch switching control circuit suitable for insulation detection of energy storage batteries. Background Technology

[0002] With the development of relay technology, small power relays have been widely used in industrial control, automotive electronics, and other fields due to their small size, lightweight, low power consumption, and excellent electrical performance. Small power relays can be directly driven by low-voltage signals such as microcontrollers (MCUs), which has led to the development of relay-based switching control.

[0003] With the development of electric vehicles and energy storage technologies, higher safety requirements are being placed on them. Insulation detection technology has therefore been developed. Currently, the commonly used detection method is the unbalanced bridge method, which uses relay switching to sample the bridge arm voltage under different states to calculate the insulation resistance. Chinese patent CN222380494U discloses a relay drive circuit and charging device. This technical solution uses two drive modules, sharing one drive signal to control one relay. It mainly addresses the issues of slow relay start-up speed and small power reduction. However, the circuit design is complex, the control is complex, the cost is high, and there is no protection design on the control side. Chinese patent CN118486566A discloses a dual-relay drive circuit structure. This technical solution provides a scheme where two relays are connected in series and driven by a single drive signal. It cannot achieve the function of driving and controlling different branch relays with a single drive signal, and similarly lacks protection design on the control side. It is evident that most existing technologies focus on the energy design and distribution on the relay contact side, even adding control strategies to achieve rapid relay start-up and power reduction design after relay conduction. These technologies are complex in circuit design and control, costly, and lack protection design on the control side, urgently requiring further improvement. Utility Model Content

[0004] The purpose of this invention is to provide a novel switch control circuit suitable for insulation detection of energy storage batteries. It drives and controls three relays through two drive signals, simplifies the circuit structure, reduces the use of control IC I / O ports, and adds protection design on the drive control side to isolate and protect the control IC.

[0005] To achieve the above objectives, this utility model provides the following solution:

[0006] A novel switch control circuit for insulation detection of energy storage batteries includes an energy storage battery insulation detection circuit and a relay drive control circuit. The energy storage battery insulation detection circuit includes a first relay switch circuit, a second relay switch circuit, and a third relay switch circuit. The second and third relay switch circuits are connected in series and connected to the positive and negative terminals of the energy storage battery. One end of the first relay switch circuit is grounded, and the other end is connected to the midpoint of the connection between the second and third relay switch circuits.

[0007] The relay drive control circuit includes a control IC, a level conversion chip, and a drive circuit. The control IC has two drive control signal output interfaces. The level conversion chip is electrically connected to the two drive control signal output interfaces. The level conversion chip also has two drive signal output interfaces, which are directly electrically connected to the drive signal input interface of the drive circuit. Furthermore, the two drive signal output interfaces are respectively connected to the two input terminals of a common cathode diode D1. The output terminal of the common cathode diode D1 is electrically connected to the drive signal input interface of the drive circuit. The drive circuit is electrically connected to the first relay switching circuit, the second relay switching circuit, and the third relay switching circuit.

[0008] Furthermore, the first relay switch circuit, the second relay switch circuit, and the third relay switch circuit all adopt a series circuit of relay switch and resistor group, wherein the resistor group is composed of several resistors connected in series and parallel.

[0009] Furthermore, the energy storage battery insulation detection circuit also includes a first equivalent insulation resistance and a second equivalent insulation resistance. One end of the first equivalent insulation resistance is connected to the positive terminal of the energy storage battery, and the other end is grounded. One end of the second equivalent insulation resistance is connected to the negative terminal of the energy storage battery, and the other end is grounded.

[0010] Furthermore, the driving circuit includes three sets of relay driving circuits, which are used to drive the relay switches in the first relay switch circuit, the second relay switch circuit, and the third relay switch circuit, respectively.

[0011] Each relay drive circuit includes resistor R4, resistor R5, NPN transistor Q1, diode D2, and relay coil. One end of the relay coil is connected to a 12V power supply, and the other end is connected to the collector of NPN transistor Q1. Diode D2 is connected in parallel across the relay coil. The emitter of NPN transistor Q1 is grounded, and its base is connected to one end of resistors R4 and R5 respectively. The other end of resistor R5 is grounded, and the other end of resistor R4 is connected to the drive signal input interface.

[0012] Furthermore, the drive control signal output interface outputs a 3.3V high-level signal, and the level conversion chip is used to convert the 3.3V high-level signal into a 5V high-level signal, which is then output through the drive signal output interface.

[0013] Furthermore, the level conversion chip is model SN74LVC4245A.

[0014] Furthermore, the control IC is a DSP, MCU, or CPLD.

[0015] According to the specific embodiments provided by this utility model, the following technical effects are disclosed: The novel switch switching control circuit for energy storage battery insulation detection provided by this utility model adds a level conversion chip to the drive control circuit, improves the drive signal level to enhance the reliability of drive control, reduces malfunctions caused by signal interference, and provides certain isolation protection for the control IC (which may be a DSP, MCU, CPLD, etc.) to prevent relay-side signals from coupling to the control side and causing damage to the control IC; at the same time, this utility model proposes a circuit structure based on the energy storage battery insulation detection circuit that drives and controls 3 relays through 2 drive signals, reducing the use of control IC I / O ports, reducing resource consumption, and simplifying circuit design. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a topology diagram of the energy storage battery insulation detection circuit of this utility model;

[0018] Figure 2 This is a block diagram of the relay drive control circuit structure of this utility model;

[0019] Figure 3 This is a topology diagram of the relay drive circuit of this utility model. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] This invention provides a novel switch switching control circuit based on energy storage battery insulation detection, which can protect the control IC and simplify circuit design.

[0022] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] like Figures 1-2 As shown, this utility model provides a novel switch switching control circuit suitable for insulation detection of energy storage batteries, including an energy storage battery insulation detection circuit and a relay drive control circuit.

[0024] The energy storage battery insulation detection circuit includes a first relay switch circuit, a second relay switch circuit, and a third relay switch circuit. The second relay switch circuit and the third relay switch circuit are connected in series and connected to the positive terminal B+ and the negative terminal B- of the energy storage battery. One end of the first relay switch circuit is grounded (PE), and the other end is connected to the midpoint of the connection between the second relay switch circuit and the third relay switch circuit.

[0025] Specifically, the first relay switch circuit includes a relay switch S1 and a resistor group R1, the second relay switch circuit includes a relay switch S2 and a resistor group R2, and the third relay switch circuit includes a relay switch S3 and a resistor group R3. Each resistor group R1, R2, and R3 represents a set of series and parallel resistors. The specific number of series and parallel resistors is matched according to the voltage level of the energy storage battery. The resistance values ​​of R1, R2, and R3 are generally equal for easy calculation. For example, when the energy storage battery voltage level is 300V, the resistance values ​​of R1, R2, and R3 can be selected as 200kΩ.

[0026] The energy storage battery insulation detection circuit also includes a first equivalent insulation resistance Rx and a second equivalent insulation resistance Ry. One end of the first equivalent insulation resistance Rx is connected to the positive terminal B+ of the energy storage battery, and the other end is grounded (PE). One end of the second equivalent insulation resistance Ry is connected to the negative terminal B- of the energy storage battery, and the other end is grounded (PE).

[0027] When the energy storage battery is working normally, relay switches S1, S2, and S3 are all in the open state. During insulation testing, it is necessary to first close relay switches S1 and S2 to measure a set of voltage values, then open relay switches S1 and S2, and then close relay switches S1 and S3 again to measure a set of voltage values.

[0028] The relay drive control circuit meets the above control requirements. Typically, three drive control signals are needed to control relay switches S1, S2, and S3 respectively. However, the circuit structure provided by this invention only requires two drive control signals to achieve the above control requirements. The circuit structure block diagram is shown below. Figure 2 .

[0029] The relay drive control circuit includes a control IC (which may be a DSP, MCU, CPLD, etc.), a level conversion chip U1, and a drive circuit. The control IC has two drive control signal output interfaces a and b, and the output drive control signal is generally 3.3V high level active. The level conversion chip is electrically connected to the two drive control signal output interfaces a and b. The level conversion chip has two drive signal output interfaces c and d. The level conversion chip is used to convert the 3.3V high level signal into a 5V high level signal, which is then output through the drive signal output interfaces c and d.

[0030] The two drive signal output interfaces c and d are directly electrically connected to the drive signal input interface of the drive circuit. Furthermore, the two drive signal output interfaces c and d are respectively connected to the two input terminals of the common cathode diode D1, and the output terminal e of the common cathode diode D1 is electrically connected to the drive signal input interface of the drive circuit. The drive circuit is electrically connected to the first relay switch circuit, the second relay switch circuit, and the third relay switch circuit, respectively.

[0031] The driving circuit includes three sets of relay driving circuits, which are used to drive the relay switches in the first, second, and third relay switching circuits, respectively. For example, the driving signals output from the driving signal output interfaces c and d are used to control relay switches S2 and S3, respectively, and the driving signal output from the output terminal e of the common cathode diode D1 is used to control relay switch S1. When either relay switch S2 or S3 needs to be engaged, relay switch S1 is also engaged, thus meeting the required driving requirements and design needs. This circuit design is simple and effective.

[0032] like Figure 3 As shown, each relay drive circuit includes resistor R4, resistor R5, NPN transistor Q1, diode D2, and relay coil. One end of the relay coil is connected to a 12V power supply, and the other end is connected to the collector of NPN transistor Q1. Diode D2 is connected in parallel across the relay coil, providing a freewheeling circuit for the relay coil RLY1 when the drive is turned off. The emitter of NPN transistor Q1 is grounded, and its base is connected to one end of resistor R4 and resistor R5 respectively. The other end of resistor R5 is grounded, and the other end of resistor R4 is connected to the drive signal input interface.

[0033] The working principle of relay switches S1, S2, and S3: When the drive control signal is high, the NPN transistor Q1 is turned on, the two ends of the relay coil RLY1 are energized, and the relay coil RLY1 is energized; when the drive signal is low, the NPN transistor Q1 is not turned on, and the relay coil RLY1 is disconnected.

[0034] For example, the level conversion chip is model SN74LVC4245A.

[0035] This invention uses a level conversion chip U1 to convert the 3.3V drive control signal output by the control IC into a 5V drive signal. The 5V level is higher and less susceptible to interference during signal transmission, thus improving the reliability of relay drive control. At the same time, the level conversion chip U1 isolates the control IC port from the relay side, preventing the relay side signal from coupling to the control side and causing damage to the control IC. The built-in protection function of the level conversion chip U1 provides better protection.

[0036] This invention achieves the function of controlling three relays through two drive control signals by adding a common cathode diode D1, thereby reducing the use of control IC I / O ports, reducing resource consumption, simplifying circuit design and reducing costs.

[0037] The remaining technical features in this embodiment can be flexibly selected by those skilled in the art to meet different specific practical needs. However, it is obvious to those skilled in the art that these specific details are not necessary to implement this utility model. In other instances, to avoid obscuring this utility model, well-known components, structures, or parts are not specifically described, and all are within the scope of technical protection defined by the claims of this utility model.

[0038] Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of this utility model should be protected within the scope of the appended claims. In the above description, numerous specific details have been set forth to provide a thorough understanding of this utility model. However, it will be apparent to those skilled in the art that these specific details are not necessary to implement this utility model. In other instances, to avoid obscuring this utility model, well-known techniques, such as specific construction details, operating conditions, and other technical conditions, have not been specifically described.

[0039] This document uses specific examples to illustrate the principles and implementation methods of this utility model. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this utility model. Furthermore, those skilled in the art will recognize that, based on the ideas of this utility model, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A novel switch-changing control circuit suitable for insulation detection of energy storage batteries, characterized in that, include: An energy storage battery insulation detection circuit and a relay drive control circuit are provided. The energy storage battery insulation detection circuit includes a first relay switch circuit, a second relay switch circuit, and a third relay switch circuit. The second relay switch circuit and the third relay switch circuit are connected in series and connected to the positive and negative terminals of the energy storage battery. One end of the first relay switch circuit is grounded, and the other end is connected to the midpoint of the connection between the second relay switch circuit and the third relay switch circuit. The relay drive control circuit includes a control IC, a level conversion chip, and a drive circuit. The control IC has two drive control signal output interfaces. The level conversion chip is electrically connected to the two drive control signal output interfaces. The level conversion chip also has two drive signal output interfaces, which are directly electrically connected to the drive signal input interface of the drive circuit. Furthermore, the two drive signal output interfaces are respectively connected to the two input terminals of a common cathode diode D1. The output terminal of the common cathode diode D1 is electrically connected to the drive signal input interface of the drive circuit. The drive circuit is electrically connected to the first relay switching circuit, the second relay switching circuit, and the third relay switching circuit.

2. The novel switch-changing control circuit for insulation detection of energy storage batteries according to claim 1, characterized in that, The first, second, and third relay switch circuits all employ a series circuit of a relay switch and a resistor group, wherein the resistor group is composed of several resistors connected in series and parallel.

3. The novel switch-changing control circuit for insulation detection of energy storage batteries according to claim 1, characterized in that, The energy storage battery insulation detection circuit further includes a first equivalent insulation resistance and a second equivalent insulation resistance. One end of the first equivalent insulation resistance is connected to the positive terminal of the energy storage battery, and the other end is grounded. One end of the second equivalent insulation resistance is connected to the negative terminal of the energy storage battery, and the other end is grounded.

4. The novel switch-changing control circuit for insulation detection of energy storage batteries according to claim 2, characterized in that, The driving circuit includes three sets of relay driving circuits, which are used to drive the relay switches in the first relay switch circuit, the second relay switch circuit and the third relay switch circuit, respectively. Each relay drive circuit includes resistor R4, resistor R5, NPN transistor Q1, diode D2, and relay coil. One end of the relay coil is connected to a 12V power supply, and the other end is connected to the collector of NPN transistor Q1. Diode D2 is connected in parallel across the relay coil. The emitter of NPN transistor Q1 is grounded, and its base is connected to one end of resistors R4 and R5 respectively. The other end of resistor R5 is grounded, and the other end of resistor R4 is connected to the drive signal input interface.

5. The novel switch-changing control circuit for insulation detection of energy storage batteries according to claim 1, characterized in that, The drive control signal output interface outputs a 3.3V high-level signal, and the level conversion chip is used to convert the 3.3V high-level signal into a 5V high-level signal, which is then output through the drive signal output interface.

6. The novel switch-changing control circuit for insulation detection of energy storage batteries according to claim 1, characterized in that, The level conversion chip is model SN74LVC4245A.

7. The novel switch-changing control circuit for insulation detection of energy storage batteries according to claim 1, characterized in that, The control IC is a DSP, MCU, or CPLD.

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