Driving circuit of high-voltage direct-current contactor for vehicle

Abstract

The utility model discloses a driving circuit of a vehicle high-voltage direct current contactor, which relates to the field of new energy automobiles, and adopts the technical scheme that the driving circuit comprises a high-voltage driving module, a low-voltage driving module, a control module and a direct current contactor module, the high-voltage driving module comprises a first direct current power supply, a resistor R3, a resistor R4, a resistor R5, a resistor R10, a capacitor C1 and a transistor Q2, the first end of the transistor Q2 is connected with a first direct-current source, the second end of the transistor Q2 is connected with one end of the resistor R3, a common PWM driving mode is abandoned, large current for coil working is provided in the high-voltage stage, small current for coil working is provided in the low-voltage stage, timing from the high-voltage stage to the low-voltage stage is achieved through an RC circuit, and the high-voltage stage, the low-voltage stage and the high-voltage stage are integrated. Compared with a PWM driving mode, part of energy consumption is reduced, the risk of burning a high-voltage direct-current contactor coil is also reduced, and the problem of occupying port resources of a chip is also solved.

Description

Technical Field

[0001] The utility model relates to the field of new energy vehicles, and in particular to a driving circuit of a high-voltage direct current contactor for a vehicle. Background Art

[0002] In new energy electric vehicles, the battery management system is responsible for monitoring and protecting the main circuit of the vehicle, and plays a vital role in the safe operation of the vehicle. The battery management system uses high-voltage DC contactors to connect the main circuit and disconnect it in time in safety-affecting situations such as overcurrent, overtemperature, overvoltage and undervoltage.

[0003] The interior of the high-voltage DC contactor consists of an armature and an electromagnetic coil. Its driving characteristics are as follows: first, a large current of level A is instantly connected to pull the armature to a reliable energized position, and then a small current of level mA is used to maintain the energized state. The usual driving circuit is as follows Figure 2 , is to use PWM signal to drive the transistor to achieve adjustable working current of the high-voltage side circuit. Specifically, when a large current is needed, the controller outputs a PWM square wave with a large duty cycle, and when a small current is needed, it outputs a PWM square wave with a small duty cycle. The main disadvantage of this driving method is that the high-voltage side always works in a discontinuous state, resulting in current on the freewheeling diode all the time, consuming more energy. Once PWM fails, the high-voltage side will be directly turned on and the coil of the high-voltage DC contactor will be burned, and the port resources of the chip will be occupied. It is difficult to free up port resources in some applications. Utility Model Content

[0004] In order to achieve the above utility model purpose and to solve the above technical problems, the utility model provides a driving circuit of a high-voltage DC contactor for a vehicle.

[0005] The technical solution is as follows: it includes a high-voltage drive module, a low-voltage drive module, a control module, and a DC contactor module. The high-voltage drive module includes a first DC power supply, a resistor R3, a resistor R4, a resistor R5, a resistor R10, a capacitor C1, and a transistor Q2. The first end of the transistor Q2 is connected to the first DC source, the second end of the transistor Q2 is connected to one end of the resistor R3, and the other end of the resistor R3 is connected to the first DC source. The third end of the transistor Q2 is connected to one end of the resistor R10, and the other end of the resistor R10 is connected to the input end of the DC contactor module. The second end of the transistor Q2 is also connected to one end of the resistor R4, and the other end of the resistor R4 is connected to the first end of the capacitor C1, and the second end of the capacitor C1 is connected to the output end of the DC contactor module. The other end of the resistor R3 is connected to one end of the resistor R5, and the other end of the resistor R5 is connected to the second end of the capacitor C1. The low-voltage drive module is connected to the input end of the DC contactor module, and the control module is connected to the output end of the DC contactor.

[0006] Preferably, the low-voltage driving module comprises a second DC source and a diode D1 , wherein the anode of the diode D1 is connected to the second DC source, and the cathode of the diode D1 is connected to the input end of the DC contactor module.

[0007] Preferably, it is characterized in that the control module includes a control end, a resistor R1, a resistor R6, a resistor R2, a transistor Q1, and a light-emitting diode LED1, the first end of the transistor Q1 is grounded, the second end of the transistor Q1 is connected to the control end through R1, the second end of the transistor Q1 is also connected to one end of R2, the other end of the resistor R2 is grounded, the positive electrode of the light-emitting diode LED1 is connected to the control end through the resistor R6, the negative electrode of the light-emitting diode LED1 is grounded, and the third end of the transistor Q1 is connected to the output end of the DC contactor module.

[0008] Preferably, the DC contactor module includes a high-voltage DC contactor coil, a diode D2, the cathode of the diode D2 is connected to the cathode of the diode D1 and the other end of the resistor R10, the anode of the light-emitting diode LED1 is connected to the other end of the capacitor C1 and the third end of the transistor Q1, and the high-voltage DC contactor coil is connected in parallel with the light-emitting diode LED1.

[0009] Preferably, it is characterized in that the first DC source is formed by battery packs connected in series, and the second DC source is a 12V vehicle-mounted battery management system.

[0010] Preferably, it is characterized in that the transistor Q2 is a PMOS tube, the first end of the transistor Q2 is the source of the PMOS tube, the second end of the transistor Q2 is the gate of the PMOS tube, and the third end of the transistor Q2 is the drain of the PMOS tube.

[0011] Preferably, it is characterized in that the transistor Q1 is an NMOS tube, the first end of the transistor Q1 is the source of the NMOS tube, the second end of the transistor Q2 is the gate of the NMOS tube, and the third end of the transistor Q2 is the drain of the NMOS tube.

[0012] The beneficial effects of the technical solution provided by the embodiment of the utility model are as follows: the utility model patent abandons the commonly used PWM driving mode and provides a driving mode for automatically switching high voltage and low voltage for vehicle use. In the high voltage stage, the battery pack is connected in series with a current limiting resistor to provide a large current for the coil to work, and in the low voltage stage, the switching power supply of the battery management system is directly used to maintain a small current for the coil to work. The timing from the high voltage stage to the low voltage stage is achieved using an RC circuit. Since the high voltage side circuit is always connected, the working current in the freewheeling diode is almost zero, thereby reducing some energy consumption compared to the PWM driving mode. The series resistance and the switching power supply also reduce the risk of burning the high voltage DC contactor coil, and also solve the problem of occupying the port resources of the chip. The circuit has high reliability and is easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram used to illustrate a vehicle driving circuit in the present utility model.

[0014] Figure 2 The utility model provides a schematic diagram of driving a high-voltage DC contactor for a vehicle. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. Of course, the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0016] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0017] In the description of the invention of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the invention of the utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the invention of the utility model. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the invention of the present utility model, unless otherwise specified, "multiple" means two or more.

[0018] In the description of the invention of the utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention of the utility model can be understood according to specific circumstances.

[0019] Example 1

[0020] See also Figure 1 to Figure 2 The utility model provides a driving circuit of a high-voltage DC contactor for a vehicle, comprising a high-voltage driving module, a low-voltage driving module, a control module, and a DC contactor module. The high-voltage driving module comprises a first DC power supply, a resistor R3, a resistor R4, a resistor R5, a resistor R10, a capacitor C1, and a transistor Q2. The first end of the transistor Q2 is connected to the first DC source, the second end of the transistor Q2 is connected to one end of the resistor R3, the other end of the resistor R3 is connected to the first DC source, the third end of the transistor Q2 is connected to one end of the resistor R10, the other end of the resistor R10 is connected to the input end of the DC contactor module, the second end of the transistor Q2 is also connected to one end of the resistor R4, the other end of the resistor R4 is connected to the first end of the capacitor C1, the second end of the capacitor C1 is connected to the output end of the DC contactor module, the other end of the resistor R3 is connected to one end of the resistor R5, the other end of the resistor R5 is connected to the second end of the capacitor C1, the low-voltage driving module is connected to the input end of the DC contactor module, and the control module is connected to the output end of the DC contactor.

[0021] Specifically, the low-voltage driving module includes a second DC source and a diode D1 , wherein the anode of the diode D1 is connected to the second DC source, and the cathode of the diode D1 is connected to the input end of the DC contactor module.

[0022] Specifically, the control module includes a control end, a resistor R1, a resistor R6, a resistor R2, a transistor Q1, and a light-emitting diode LED1. The first end of the transistor Q1 is grounded, the second end of the transistor Q1 is connected to the control end through R1, the second end of the transistor Q1 is also connected to one end of R2, the other end of the resistor R2 is grounded, the positive electrode of the light-emitting diode LED1 is connected to the control end through the resistor R6, the negative electrode of the light-emitting diode LED1 is grounded, the third end of the transistor Q1 is connected to the output end of the DC contactor module, the conduction time of the transistor Q2 is determined by the delay circuit composed of resistors R3, R4 and the control capacitor C1, and the delay time of the delay circuit must be adjusted to be greater than the high-current working time of the high-voltage DC contactor to ensure that the contactor is fully attracted.

[0023] Specifically, the DC contactor module includes a high-voltage DC contactor coil, a diode D2, the cathode of the diode D2 is connected to the cathode of the diode D1 and the other end of the resistor R10, the anode of the light-emitting diode LED1 is connected to the other end of the capacitor C1 and the third end of the transistor Q1, and the high-voltage DC contactor coil is connected in parallel with the light-emitting diode LED1.

[0024] Specifically, the first DC source is formed by a battery pack connected in series, and the second DC source is a 12V vehicle-mounted battery management system.

[0025] Specifically, the transistor Q2 is a PMOS tube, the first end of the transistor Q2 is the source of the PMOS tube, the second end of the transistor Q2 is the gate of the PMOS tube, and the third section of the transistor Q2 is the drain of the PMOS tube. The transistor can also be a field effect tube.

[0026] Specifically, the transistor Q1 is an NMOS tube, the first end of the transistor Q1 is the source of the NMOS tube, the second end of the transistor Q2 is the gate of the NMOS tube, and the third end of the transistor Q2 is the drain of the NMOS tube. The field effect tube can also be a field effect tube or a triode.

[0027] When the utility model is used, the high voltage and low voltage are automatically switched through the RC circuit to meet the characteristics of the high-voltage DC contactor with instantaneous large current and small current in the maintenance stage. In the initial state, the controller outputs a low level, the NMOS tube Q1 is cut off, and there is no charge in the control capacitor C1 in the high-voltage side circuit. When the controller outputs a high level as required, the NMOS tube is turned on, and the control capacitor C1 starts to charge, the PMOS tube Q2 on the high-voltage side is turned on, and the voltage VBAT of the battery pack provides a large current to the coil of the high-voltage DC contactor through the current limiting resistor R10, and the contactor is instantly connected; as the positive voltage of the control capacitor C1 increases, the gate voltage of the PMOS tube Q2 increases, and when the voltage difference between the gate voltage and the drain voltage reaches the threshold voltage, the PMOS tube is automatically turned off, so that only the switching power supply of the battery management system is used for power supply. Although the supply current of the switching power supply is small, it still meets the current demand of the coil to maintain the contactor on.

[0028] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A driving circuit for a high voltage DC contactor for a vehicle, characterized in that: It includes a high-voltage drive module, a low-voltage drive module, a control module, and a DC contactor module. The high-voltage drive module includes a first DC power supply, a resistor R3, a resistor R4, a resistor R5, a resistor R10, a capacitor C1, and a transistor Q2. The first end of the transistor Q2 is connected to the first DC source, the second end of the transistor Q2 is connected to one end of the resistor R3, and the other end of the resistor R3 is connected to the first DC source. The third end of the transistor Q2 is connected to one end of the resistor R10, and the other end of the resistor R10 is connected to the input end of the DC contactor module. The second end of the transistor Q2 is also connected to one end of the resistor R4, and the other end of the resistor R4 is connected to the first end of the capacitor C1, and the second end of the capacitor C1 is connected to the output end of the DC contactor module. The other end of the resistor R3 is connected to one end of the resistor R5, and the other end of the resistor R5 is connected to the second end of the capacitor C1. The low-voltage drive module is connected to the input end of the DC contactor module, and the control module is connected to the output end of the DC contactor. The low-voltage driving module includes a second DC source and a diode D1, wherein the anode of the diode D1 is connected to the second DC source, and the cathode of the diode D1 is connected to the input end of the DC contactor module; The control module includes a control end, a resistor R1, a resistor R6, a resistor R2, a transistor Q1, and a light emitting diode LED1. The first end of the transistor Q1 is grounded, the second end of the transistor Q1 is connected to the control end through R1, the second end of the transistor Q1 is also connected to one end of R2, the other end of the resistor R2 is grounded, the positive electrode of the light emitting diode LED1 is connected to the control end through the resistor R6, the negative electrode of the light emitting diode LED1 is grounded, and the third end of the transistor Q1 is connected to the output end of the DC contactor module; The DC contactor module includes a high-voltage DC contactor coil, a diode D2, the cathode of the diode D2 is connected to the cathode of the diode D1 and the other end of the resistor R10, the anode of the light-emitting diode LED1 is connected to the other end of the capacitor C1 and the third end of the transistor Q1, and the high-voltage DC contactor coil is connected in parallel with the light-emitting diode LED1; The first DC source is formed by a battery pack connected in series, and the second DC source is a 12V vehicle-mounted battery management system; The transistor Q2 is a PMOS tube, the first end of the transistor Q2 is the source of the PMOS tube, the second end of the transistor Q2 is the gate of the PMOS tube, and the third end of the transistor Q2 is the drain of the PMOS tube; The transistor Q1 is an NMOS tube, the first end of the transistor Q1 is the source of the NMOS tube, the second end of the transistor Q2 is the gate of the NMOS tube, and the third end of the transistor Q2 is the drain of the NMOS tube.

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