Relay power supply circuit of battery management system

Abstract

The utility model discloses a relay power supply circuit of a battery management system, which comprises a power supply, a driving circuit, a holding circuit and a delay circuit, and is characterized in that the power supply is used for providing power supply voltage Vcc as input voltage; the input end of the driving circuit is connected with a power supply, the output end is connected with the input end of the holding circuit, and the output end of the holding circuit is connected with the relay and used for providing output voltage V. And the time delay circuit is used for switching the holding circuit between a high-voltage driving state and a low-voltage holding state. In the high-voltage driving state, the output voltage V is equal to the power supply voltage Vcc. In the low-voltage sustaining state, the sustaining circuit reduces the voltage value of the power supply voltage Vcc to a sustaining voltage such that the output voltage V is equal to the sustaining voltage. The power supply provides a power supply voltage Vcc as a starting voltage to the relay, and the inside of the relay is switched to a maintaining voltage through the time delay circuit after the relay is started, so that the characteristic that the relay is started by a relatively high voltage and maintained by a relatively low voltage is effectively realized.

Description

Technical Field

[0001] The utility model relates to the technical field of sensor power supply, in particular to a relay power supply circuit of a battery management system. Background Art

[0002] The development of lithium batteries has been integrated into all areas of our lives, such as electric vehicles, photovoltaic energy storage, and uninterruptible backup power systems. In the battery management system, in order to control the opening and closing of lithium batteries, high-voltage relays are usually applied. In order to achieve energy saving and relay heating, relays are usually driven by two voltages, as shown in the attached figure of the specification. Figure 1 As shown, one is a starting voltage Vcc1 with a slightly higher voltage, and the other is a maintaining voltage Vcc2 with a relatively low voltage. When the starting voltage Vcc1 is provided to drive the relay, the relay closes and operates. At this time, after the relay is closed, only a maintaining voltage Vcc2 is used to allow the relay to operate for a long time. In the prior art, the general design of relay power supply circuits adopts such a dual power supply, but this technical solution has certain disadvantages. It is necessary to design two different voltages Vcc1 and Vcc2, as well as corresponding circuits. Such circuit design is not only complex but also has a relatively high cost. Utility Model Content

[0003] In order to overcome the above disadvantages, the purpose of the present invention is to provide a relay power supply circuit for a battery management system to solve the problems caused by the above background technology.

[0004] In order to achieve the above purpose, the technical solution adopted by the utility model is a relay power supply circuit of a battery management system, including a power supply, a drive circuit, a maintenance circuit and a delay circuit, wherein: the power supply is used to provide a power supply voltage Vcc as an input voltage. The input end of the drive circuit is connected to the power supply, and the output end is connected to the input end of the maintenance circuit. The output end of the maintenance circuit is connected to a relay for providing an output voltage V.

[0005] The sustaining circuit includes a high-voltage driving state and a low-voltage sustaining state. The high-voltage driving state is when the sustaining circuit is normally turned on, and the output voltage V is equal to the power supply voltage Vcc. The low-voltage sustaining state is when the voltage value of the power supply voltage Vcc is reduced by the sustaining circuit to form a sustaining voltage, so that the output voltage V is equal to the sustaining voltage. The delay circuit is used to switch the sustaining circuit between the high-voltage driving state and the low-voltage sustaining state.

[0006] Furthermore, the driving circuit includes an MCU control unit, and the MCU control unit is used to send a high-level or low-level Drv driving signal to cooperate with the delay circuit.

[0007] Furthermore, the driving circuit includes a resistor R3, a resistor R4, a resistor R5, a resistor R6, a switch tube T1 and a transistor Q3. The source of the switch tube T1 is connected to a power supply, the drain is connected to the input end of the delay circuit, and the gate is connected to one end of the resistor R6. The two ends of the resistor R5 are respectively connected to the drain and the gate of the switch tube T1. The collector of the transistor Q3 is connected to the other end of the resistor R6, the emitter is grounded GND, and the base is connected in series with the resistor R3 to access the signal output port of the MCU control unit. The two ends of the resistor R4 are respectively connected to the emitter and the base of the transistor Q3.

[0008] Furthermore, the delay circuit includes a resistor R1, a resistor R2, a resistor R8, a capacitor C1 and a transistor Q2. The collector of the transistor Q2 is connected to one end of the resistor R8, the emitter is grounded GND, the base is connected in series with the resistor R1, and is connected to the node between the collector of the transistor Q3 and the resistor R6. The positive terminal of the capacitor C1 is connected to the node between the resistor R1 and the base of the transistor Q2, and the negative terminal is connected to the emitter of the transistor Q3. The resistor R2 is connected in parallel to both ends of the capacitor C1.

[0009] Furthermore, the maintenance circuit includes a diode D1, a diode D2, a diode D3, a diode D4, a resistor R7 and a switch tube T2. The diode D1, the diode D2, the diode D3 and the diode D4 are connected in series in sequence, the positive terminal of the diode D1 is connected to the drain of the switch tube T1, and the negative terminal of the diode D4 is connected to the output V. The source of the switch tube T2 is connected to the positive terminal of the diode D1, the drain is connected to the negative terminal of the diode D4, and the gate is connected to the other end of the resistor R8. The two ends of the resistor R7 are respectively connected to the drain and the gate of the switch tube T2.

[0010] Furthermore, the transistor Q2 and the transistor Q3 are both N-type transistors.

[0011] Furthermore, both the switch tube T1 and the switch tube T2 are P-type switch tubes.

[0012] Furthermore, the diode D1, the diode D2, the diode D3 and the diode D4 can all generate a voltage drop of 2V, which is used to output the output voltage V of the power supply voltage Vcc minus the voltage drops of multiple diodes as the maintenance voltage when the switch T2 is turned off.

[0013] Furthermore, the capacitor C1 is used to store electric energy to form a high level. When the capacitor C1 drops to a low level, the transistor Q2 is turned off, and then the switch tube T2 is turned off.

[0014] Compared with the prior art, the beneficial effects of the utility model are as follows: in order to achieve low power consumption and energy saving of the product, the current design of relays all considers the method of starting with a higher voltage and maintaining the normal operation of the relay with a lower voltage, that is, providing a slightly higher starting voltage to drive the relay, and the relay is closed. At this time, after the relay is closed, a maintenance voltage is provided to allow the relay to operate for a long time. The utility model discloses a relay power supply circuit of a battery management system, including a drive circuit, a delay circuit, and a maintenance circuit. The drive circuit provides a higher power supply voltage Vcc when the relay is started to allow the relay to close normally. The delay circuit provides a start-up time of 10ms for the relay to close, which can ensure that the relay is fully closed and provide enough time for the next step of maintaining the start of the circuit. The purpose of the maintenance circuit is to provide a lower voltage to maintain the normal operation of the relay when the relay is fully closed. The lower voltage provides the voltage drop effect of multiple diodes to reduce the starting voltage, effectively realizing the characteristics of starting with a higher voltage and maintaining the operation of the relay with a lower voltage, which can reduce the heating of the relay and increase the service life, and has a strong practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of the principle of powering a relay in the prior art;

[0016] Figure 2 This is a circuit diagram of an embodiment of a relay power supply circuit of a battery management system of the utility model;

[0017] In the figure: 1-driving circuit; 2-delay circuit; 3-maintaining circuit. DETAILED DESCRIPTION

[0018] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0019] refer to Figure 2 , Figure 2 A three-dimensional diagram of a relay power supply circuit of a battery management system provided by an embodiment of the utility model is shown.

[0020] like Figure 2 As shown, the figure shows the relay power supply circuit of the battery management system provided by the present application, including a power supply, a drive circuit 1, a maintenance circuit 3 and a delay circuit 2, wherein: the power supply is used to provide a power supply voltage Vcc as an input voltage. The input end of the drive circuit 1 is connected to the power supply, and the output end is connected to the input end of the maintenance circuit 3. The output end of the maintenance circuit 3 is connected to the relay for providing an output voltage V.

[0021] The maintenance circuit 3 includes a high-voltage driving state and a low-voltage maintenance state. The high-voltage driving state is that the maintenance circuit 3 is normally turned on, and the output voltage V is equal to the power supply voltage Vcc. The low-voltage maintenance state is that the voltage value of the power supply voltage Vcc is reduced by the maintenance circuit 3 to form a maintenance voltage, so that the output voltage V is equal to the maintenance voltage. The delay circuit 2 is used to switch the maintenance circuit 3 between the high-voltage driving state and the low-voltage maintenance state.

[0022] The relay power supply circuit of the battery management system provided by the present application provides a power supply voltage Vcc as a starting voltage to the relay through a group of power supplies, and switches to a maintenance voltage after the relay is started through a delay circuit 2. The maintenance voltage allows the relay to work in a low-loss state and can reduce the heating of the relay. The utility model has a reasonable design, a simple principle, and a low cost. It can reduce the heating of the relay and increase the service life. It has a strong practical value, effectively realizes the characteristics of starting the relay with a higher voltage and maintaining the operation of the relay with a lower voltage, and increases the service life of the relay.

[0023] In some embodiments, the driving circuit 1 includes an MCU control unit, and the MCU control unit is used to send a high-level or low-level Drv driving signal to cooperate with the delay circuit 2.

[0024] In some embodiments, reference Figure 2 , the driving circuit 1 includes a resistor R3, a resistor R4, a resistor R5, a resistor R6, a switch tube T1 and a transistor Q3. The source of the switch tube T1 is connected to the power supply, the drain is connected to the input end of the delay circuit 2, and the gate is connected to one end of the resistor R6. The two ends of the resistor R5 are respectively connected to the drain and the gate of the switch tube T1. The collector of the transistor Q3 is connected to the other end of the resistor R6, the emitter is grounded GND, and the base is connected in series with the resistor R3 to access the signal output port of the MCU control unit. The two ends of the resistor R4 are respectively connected to the emitter and the base of the transistor Q3.

[0025] Exemplarily, the transistor Q3 is regulated by the Drv driving signal, being cut off when at a low level and being turned on when at a high level.

[0026] In some embodiments, reference Figure 2 The delay circuit 2 includes a resistor R1, a resistor R2, a resistor R8, a capacitor C1 and a transistor Q2. The collector of the transistor Q2 is connected to one end of the resistor R8, the emitter is grounded GND, the base is connected in series with the resistor R1, and is connected to the node between the collector of the transistor Q3 and the resistor R6. The positive terminal of the capacitor C1 is connected to the node between the resistor R1 and the base of the transistor Q2, and the negative terminal is connected to the emitter of the transistor Q3. The resistor R2 is connected in parallel to both ends of the capacitor C1.

[0027] Exemplarily, the capacitor C1 is used as an energy storage capacitor. When energy storage is completed, a high level is formed, so that the transistor Q2 is turned on. When it is continuously discharged to a low level, the transistor Q2 is turned off.

[0028] In some embodiments, reference Figure 2 , the maintenance circuit 3 includes a diode D1, a diode D2, a diode D3, a diode D4, a resistor R7 and a switch tube T2. The diode D1, the diode D2, the diode D3 and the diode D4 are connected in series in sequence, the positive terminal of the diode D1 is connected to the drain of the switch tube T1, and the negative terminal of the diode D4 is connected to the output V. The source of the switch tube T2 is connected to the positive terminal of the diode D1, the drain is connected to the negative terminal of the diode D4, and the gate is connected to the other end of the resistor R8. The two ends of the resistor R7 are respectively connected to the drain and the gate of the switch tube T2.

[0029] Exemplarily, the switch tube T2 is used as a channel in the high-voltage driving state, so that the output voltage V is equal to the power supply voltage Vcc, and the relay is turned on and closed. The diodes D1, D2, D3, and D4 are used as channels in the low-voltage maintenance state. Through the voltage drop characteristics of the diodes, the power supply voltage Vcc is weakened to form a maintenance voltage, and the normal operation of the relay is maintained at a lower voltage.

[0030] Specifically, the transistor Q2 and the transistor Q3 are both N-type transistors, and the switch tube T1 and the switch tube T2 are both P-type switch tubes.

[0031] In some embodiments, reference Figure 2 , diode D1, diode D2, diode D3 and diode D4 can all generate a voltage drop of 2V, which is used to maintain the output voltage of V after the switch tube T2 is turned off, which is the power supply voltage Vcc minus the voltage drops of multiple diodes.

[0032] The capacitor C1 is used to store electric energy to form a high level. When the capacitor C1 drops to a low level, the transistor Q2 is turned off, and then the switch tube T2 is turned off.

[0033] The working principle of the relay power supply circuit of the battery management system provided in this application is as follows:

[0034] First, the power supply is supplied, the power supply voltage Vcc (usually 12V or 24V), and at the same time the MCU control unit outputs a control signal - Drv drive signal to control the on and off of the relay.

[0035] When the Drv driving signal is at a low level, the transistor Q3 is not turned on, and the switch tube T1 is not turned on either, so the power supply voltage Vcc has no output voltage, and the relay driven by the power supply voltage Vcc will not be closed. Since the power supply voltage Vcc supplies power to the transistor Q2 through the resistors R5, R6 and R1, at this time point B is at a high level, the transistor Q2 is turned on, the switch tube T2 is turned on, and the capacitor C1 stores electrical energy.

[0036] Exemplarily, a high level in the present application refers to a voltage higher than 2.7V, and a low level refers to a voltage lower than 0.8V.

[0037] When the Drv drive signal switches to a high level, the transistor Q3 will be turned on accordingly, causing the voltage at point A to be low. At this time, a voltage difference appears between the source and gate of the switch tube T1, causing the switch tube T1 to be turned on. At this time, due to the storage of electrical energy by capacitor C1, point B is at a high level, so the transistor Q2 is in a continuous on state, and the switch tube T2 is also turned on.

[0038] At this time, the power supply circuit of the relay starting voltage is composed of the power supply voltage Vcc through the switch tube T1 and the switch tube T2, and the output voltage V is directly output. Because the conduction voltage drop of the switch tube is very small and can be basically ignored, the output voltage V is equal to the power supply voltage Vcc. The power supply voltage Vcc provides the start-up voltage for the relay drive, that is, the high-voltage drive state.

[0039] When the high level provided by the Drv driving signal makes the transistor Q3 conduct, the voltage at point A presents a low level. At this time, the electric energy of the capacitor C1 is mainly discharged through the resistor R1 and the transistor Q3. When the discharge reaches the point B and presents a low level, the transistor Q2 changes from the on state to the off state. At this time, the source and gate of the switch tube T2 present a high level such as the power supply voltage Vcc, thereby causing the T2 tube to be closed. At this time, the power supply circuit of the maintenance circuit 3 is that the power supply voltage Vcc outputs power through the switch tube T1 and the diode D1, the diode D2, the diode D3 and the diode D4. Due to the voltage drop of the diode, at this time, the output voltage V is equal to Vcc reduced by 2V (usually the voltage drop of the diode is about 0.5V). When the driving voltage is reduced by 2V, it can not only save energy loss, but also reduce the heating of the relay. In addition, the time of the delay circuit 2 is adjusted by changing the capacitance of the capacitor C1 and the resistance of the resistor R1 to control the discharge time.

[0040] The above implementation modes are only for illustrating the technical concept and features of the utility model, and their purpose is to allow people familiar with this technology to understand the content of the utility model and implement it. It cannot be used to limit the protection scope of the utility model. Any equivalent changes or modifications made according to the spirit of the utility model should be included in the protection scope of the utility model.

Claims

1. A relay power supply circuit for a battery management system, characterized in that: It includes power supply, driving circuit, holding circuit and delay circuit, among which: The power supply is used to provide a power supply voltage Vcc as an input voltage; the input end of the driving circuit is connected to the power supply, and the output end is connected to the input end of the maintaining circuit; the output end of the maintaining circuit is connected to a relay for providing an output voltage V; The sustaining circuit includes a high-voltage driving state and a low-voltage sustaining state; the high-voltage driving state means that the sustaining circuit is normally turned on, and the output voltage V is equal to the power supply voltage Vcc; the low-voltage sustaining state means that the voltage value of the power supply voltage Vcc is reduced by the sustaining circuit to form a sustaining voltage, so that the output voltage V is equal to the sustaining voltage; The delay circuit is used to switch the maintenance circuit between the high-voltage driving state and the low-voltage maintenance state; The driving circuit includes an MCU control unit, and the MCU control unit is used to send a high-level or low-level Drv driving signal to cooperate with the delay circuit; The driving circuit includes a resistor R3, a resistor R4, a resistor R5, a resistor R6, a switch tube T1 and a transistor Q3; the source of the switch tube T1 is connected to a power supply, the drain is connected to the input end of the delay circuit, and the gate is connected to one end of the resistor R6; the two ends of the resistor R5 are respectively connected to the drain and the gate of the switch tube T1; the collector of the transistor Q3 is connected to the other end of the resistor R6, the emitter is grounded GND, and the base is connected in series with the resistor R3 to access the signal output port of the MCU control unit; the two ends of the resistor R4 are respectively connected to the emitter and the base of the transistor Q3; The delay circuit includes a resistor R1, a resistor R2, a resistor R8, a capacitor C1 and a transistor Q2; the collector of the transistor Q2 is connected to one end of the resistor R8, the emitter is grounded GND, the base is connected in series with the resistor R1, and is connected to the node between the collector of the transistor Q3 and the resistor R6; the positive terminal of the capacitor C1 is connected to the node between the resistor R1 and the base of the transistor Q2, and the negative terminal is connected to the emitter of the transistor Q3; the resistor R2 is connected in parallel to both ends of the capacitor C1; The holding circuit includes a diode D1, a diode D2, a diode D3, a diode D4, a resistor R7 and a switch tube T2; the diode D1, the diode D2, the diode D3 and the diode D4 are connected in series in sequence, the positive terminal of the diode D1 is connected to the drain of the switch tube T1, and the negative terminal of the diode D4 is connected to the output V; the source of the switch tube T2 is connected to the positive terminal of the diode D1, the drain is connected to the negative terminal of the diode D4, and the gate is connected to the other end of the resistor R8; the two ends of the resistor R7 are respectively connected to the drain and the gate of the switch tube T2; The transistor Q2 and the transistor Q3 are both N-type transistors; The switch tube T1 and the switch tube T2 are both P-type switch tubes; The diode D1, the diode D2, the diode D3 and the diode D4 can all generate a voltage drop of 2V, which is used to output the output voltage V of the power supply voltage Vcc minus the voltage drops of multiple diodes as the maintenance voltage when the switch T2 is turned off.

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