CN106564396A - Electric vehicle and precharging control circuit thereof - Google Patents

Abstract

A precharge control circuit includes a high voltage detection module, a precharge module, a delay module, a control module and a relay module. The pre-charging module and the relay module are connected in parallel between the battery pack and the electric equipment. When the high-voltage detection module detects the high-voltage signal of the battery pack, the battery pack charges the pre-charging module, and the high-voltage detection module outputs the detection result to the control module. After the control module receives the detection result, it controls the relay module to close. When the relay module is closed, the charging voltage of the pre-charging module is greater than or equal to a reference value, and the battery pack is supplied to the battery through the relay module. The electric device supplies power. The above-mentioned pre-charging control circuit can prevent the relay from being damaged due to overcurrent at the instant of closing. The invention also provides an electric vehicle using the pre-charging control circuit.

Description

Electric vehicle and its pre-charging control circuit

【Technical field】

The invention relates to the technical field of electric vehicles, in particular to an electric vehicle and a pre-charging control circuit thereof.

【Background technique】

At present, the power supply circuit of high-voltage electric accessories of electric vehicles generally adopts the structure of insurance and relay. In this structure, there is a situation that the high voltage is switched on instantaneously, and the current is too large when the high voltage is switched on instantaneously, resulting in bonding or damage of the relay, thereby reducing the reliability of the product.

In view of this, it is necessary to provide an electric vehicle and its pre-charging control circuit to overcome the above defects.

【Content of invention】

The purpose of the present invention is to provide a pre-charging control circuit that can prevent the relay from being damaged due to overcurrent at the moment of closing.

The object of the present invention is to also provide an electric vehicle using the pre-charging control circuit.

In order to achieve the above object, the present invention provides a pre-charging control circuit, the pre-charging control circuit includes a high-voltage detection module, a pre-charging module, a delay module, a control module and a relay module, the high-voltage detection module and the battery pack and the The delay module is connected, the control module is connected with the delay module and the relay module, the pre-charging module and the relay module are connected in parallel between the battery pack and the electrical equipment, when the high voltage When the detection module detects the high-voltage signal of the battery pack, the battery pack charges the pre-charging module, and the high-voltage detection module outputs the detection result to the control module after being delayed by the delay module. After the control module receives the detection result, it controls the relay module to close. When the relay module is closed, the charging voltage of the pre-charging module is greater than or equal to a reference value, and the battery pack supplies the battery pack to the relay module through the relay module. Power supply for the electrical equipment mentioned above.

Further, the high voltage detection module includes a first resistor and a second resistor, the first end of the first resistor is connected to the battery pack, the second end of the first resistor is connected to the delay module, and ground through the second resistor.

Further, the pre-charging module includes a third resistor and a first capacitor, the first end of the third resistor is connected to the battery pack, the second end of the third resistor is connected to the electrical equipment and the connected to the relay module and grounded through the first capacitor.

Further, the voltage Uc(t) of the first capacitor=Vb*(1-exp(-t/r3*c1)), wherein, Vb represents the voltage output by the battery pack, and exp() represents The exponential function of the bottom, t represents the pre-charging time, r3 represents the resistance value of the third resistor, c1 represents the capacitance of the first capacitor, and the voltage Uc(t) of the first capacitor is the pre-charging module the charging voltage.

Further, the delay module includes a second capacitor and a fourth resistor, the first end of the second capacitor is connected to the high voltage detection module, the second end of the second capacitor is connected to the control module, And grounded through the fourth resistor, the delay of the delay module is greater than or equal to the pre-charging time when the charging voltage of the pre-charging module reaches the reference value.

Further, the control module includes a timer and an electronic switch, the timer includes a trigger pin and an output pin, the trigger pin is connected to the delay module to receive the detection result, and the output pin The pin is connected to the first end of the electronic switch, the second end of the electronic switch is grounded, and the third end of the electronic switch is connected to the relay module.

Further, the relay module includes a relay, the relay includes a coil and a switch, the first end of the coil is connected to the power supply, the second end of the coil is connected to the third end of the electronic switch, and the switch The first end of the switch is connected with the battery pack, and the second end of the switch is connected with the electric equipment and the pre-charging module.

Further, the relay module further includes a diode, the anode of the diode is connected to the second end of the coil, and the cathode of the diode is connected to the first end of the coil.

Further, the electronic switch is an NMOS field effect transistor, and the first terminal, the second terminal and the third terminal of the electronic switch correspond to the gate, the drain and the source of the NMOS field effect transistor respectively.

In order to achieve the above object, the present invention also provides an electric vehicle, which includes the above-mentioned pre-charging control circuit, a battery pack and electrical equipment, and the battery pack supplies power to the user through the pre-charging control circuit. Power supply for electrical equipment.

Compared with the prior art, the present invention uses the delay module to delay the time when the detection result triggers the control module, so that the relay module is closed after the charging voltage of the pre-charging module reaches the reference value , thereby reducing the voltage difference between the two ends of the relay module, thereby effectively preventing the relay module from being damaged due to overcurrent at the moment of closing, and improving the reliability of the electric vehicle.

【Description of drawings】

Fig. 1 is a functional block diagram of an electric vehicle provided by an embodiment of the present invention.

FIG. 2 is a circuit diagram of the precharge control circuit in FIG. 1 .

【detailed description】

In order to make the objectives, technical solutions and beneficial technical effects of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described implementation Examples are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the invention. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention.

Please refer to FIG. 1 . FIG. 1 is a functional block diagram of an electric vehicle 10 provided by an embodiment of the present invention. The electric vehicle 10 includes a pre-charging control circuit 100 , a battery pack 200 and an electrical device 300 . The battery pack 200 supplies power to the electric device 300 through the pre-charging control circuit 100 . In this embodiment, the electrical equipment 300 includes one or more of an air conditioner, an oil pump controller, an air pump controller, and a DC/DC Converter.

The precharge control circuit 100 includes a high voltage detection module 110 , a precharge module 120 , a delay module 130 , a control module 150 and a relay module 160 . The high voltage detection module 110 is connected with the battery pack 200 and the delay module 130 . The control module 150 is connected to the delay module 130 and the relay module 160 . The pre-charging module 120 and the relay module 160 are connected in parallel between the battery pack 200 and the electric device 300 . When the high-voltage detection module 110 detects the high-voltage signal of the battery pack 200, the battery pack 200 charges the pre-charging module 120, and the high-voltage detection module 110 delays the detection result through the delay module 130. output to the control module 150 after hours. After receiving the detection result, the control module 150 controls the relay module 160 to close. When the relay module 160 is closed, the charging voltage of the pre-charging module 120 is greater than or equal to a reference value, and the battery pack 200 passes The relay module 160 supplies power to the electrical device 300 .

Please refer to FIG. 2 . FIG. 2 is a circuit diagram of a precharge control circuit 100 provided by an embodiment of the present invention. The high voltage detection module 110 includes a first resistor R1 and a second resistor R2. A first end of the first resistor R1 is connected to the battery pack 200, a second end of the first resistor R1 is connected to the delay module 130, and grounded through the second resistor R2.

The pre-charging module 120 includes a third resistor R3 and a first capacitor C1. The first end of the third resistor R3 is connected to the battery pack 200, the second end of the third resistor R3 is connected to the electrical equipment 300 and the relay module 160, and is connected to the first capacitor through the first end. C1 is grounded.

The delay module 130 includes a second capacitor C2 and a fourth resistor R4. A first end of the second capacitor C2 is connected to the high voltage detection module 110, a second end of the second capacitor C2 is connected to the control module 150, and grounded through the fourth resistor R4.

The control module 150 includes a timer U1 and an electronic switch Q1. The timer U1 includes a trigger pin TRIG and an output pin OUT, the trigger pin TRIG is connected to the delay module 130 to receive the detection result, the output pin OUT is connected to the electronic switch Q1 The first end is connected. The second end of the electronic switch Q1 is grounded, and the third end of the electronic switch Q1 is connected to the relay module 160 .

In this embodiment, the timer U1 further includes a reset pin RESET, a power pin VCC and a ground pin GND. The reset pin RESET and the power pin VCC are connected to the power supply V1, and the ground pin GND is grounded.

The relay module 160 includes a relay 166, and the relay 166 includes a coil J1 and a switch K1. The first end of the coil J1 is connected to the power supply V1, the second end of the coil J1 is connected to the third end of the electronic switch Q1, and the first end of the switch K1 is connected to the battery pack 200 , the second end of the switch K1 is connected to the electric device 300 and the pre-charging module 120 .

The relay module 160 further includes a diode D1, the anode of the diode D1 is connected to the second end of the coil J1, and the cathode of the diode D1 is connected to the first end of the coil J1. In this embodiment, the diode D1 is used to consume the electric energy of the coil J1 when the electronic switch Q1 is turned off.

In this embodiment, the electronic switch Q1 is an NMOS field effect transistor, and the first terminal, the second terminal and the third terminal of the electronic switch Q1 correspond to the gate, the drain and the gate of the NMOS field effect transistor respectively. source. In other implementation manners, the electronic switch Q1 can be other switches with similar functions, such as NPN transistors and IGBTs.

The working principle of the electric vehicle 10 and its pre-charging control circuit 100 of the present invention will be described below.

When the battery pack 200 outputs high voltage, the battery pack 200 charges the first capacitor C1 through the third resistor R3. The voltage Uc(t) of the first capacitor C1=Vb*(1-exp(-t/r3*c1)), wherein, Vb represents the voltage output by the battery pack 200, and exp() represents the base e is an exponential function, t represents the pre-charging time, r3 represents the resistance value of the third resistor R3, and c1 represents the capacitance value of the first capacitor C1. The voltage Uc(t) of the first capacitor C1 is the charging voltage of the pre-charging module 120 . The current i(t)=(Vb-Uc(t))/r3 flowing through the third resistor R3.

The first resistor R1 and the second resistor R2 divide the high voltage output by the battery pack 200 , and use the voltage divided by the second resistor R2 as the detection result of the high voltage detection module 110 output to the delay module 130. The delay module 130 delays the detection result by T=1.1*c2*r4 (wherein, c2 represents the capacitance of the second capacitor C2, and r4 represents the resistance of the fourth resistor R4), and then The detection result is output to the trigger pin TRIG of the timer U1 to trigger the timer U1 to start working.

The output pin OUT of the timer U1 outputs a control signal to the first end of the electronic switch Q1, so that the electronic switch Q1 is turned on, a current flows in the coil J1, and the switch K1 is closed. The voltage difference between the first terminal and the second terminal of the switch K1 is Uk(t)=Vb−Uc(t). It can be seen that, the larger the voltage Uc(t) of the first capacitor C1 is, the smaller the voltage difference Uk(t) between the first terminal and the second terminal of the switch K1 is, and the voltage flowing through the switch K1 The smaller the current. In this embodiment, when the electronic switch Q1 is turned on, the current flowing through the coil J1 meets the current requirement for driving the switch K1 to close, that is, the electronic switch Q1 can meet the current for driving the relay 166 Require.

In order to prevent the relay 166 from being damaged due to overcurrent at the moment of closing, it is necessary to control the current flowing through the switch K1 within a safe range when the relay 166 is closed, that is, to control the current flowing through the switch K1 when the relay 166 is closed. The voltage difference between the first end and the second end of the switch K1 decreases to a certain range, that is, the switch K1 needs to be closed only after the charging voltage of the pre-charging module 120 reaches a reference value. In this embodiment, the delay T of the delay module 130 is greater than or equal to the pre-charge time t before the charging voltage of the pre-charging module 120 reaches the reference value. Therefore, when the switch K1 is closed, the The charging voltage of the pre-charging module 120 is greater than or equal to the reference value, and the current flowing through the switch K1 is within a safe range, thereby effectively preventing the relay 166 from being damaged due to overcurrent at the instant of closing.

The present invention uses the delay module 130 to delay the time when the detection result triggers the control module 150, so that the relay module 160 is closed after the charging voltage of the pre-charging module 120 reaches the reference value, thereby reducing The voltage difference between the two ends of the relay module 160 is reduced, thereby effectively preventing the relay module 160 from being damaged due to overcurrent at the moment of closing, and improving the reliability of the electric vehicle 10 .

The present invention is not limited to the description in the description and the embodiments, so those skilled in the art can easily realize additional advantages and modifications, so without departing from the spirit and scope of the general concept defined by the claims and equivalent scope Without limitation, the invention is not limited to the specific details, representative apparatus, and illustrative examples shown and described herein.

Claims (10)

1. a kind of precharge control circuit, it is characterised in that：The precharge control circuit includes high pressure detection module, precharge Module, time delay module, control module and relay module, the high pressure detection module and battery pack and the time delay module phase Even, the control module is connected with the time delay module and the relay module, the pre-charge module and the relay Wired in parallel between the battery pack and electrical equipment, when the high pressure detection module detect the battery pack high pressure letter Number when, the battery pack charges to the pre-charge module, and the high pressure detection module is by time delay module described in testing result Jing Export after time delay to the control module, the control module is received after the testing result, control the relay module Closure, when the relay module is closed, the charging voltage of the pre-charge module is more than or equal to reference value, the battery pack Powered to the electrical equipment by the relay module.

2. precharge control circuit as claimed in claim 1, it is characterised in that：The high pressure detection module includes first resistor And second resistance, the first end of the first resistor is connected with the battery pack, and the second end of the first resistor is prolonged with described When module be connected, and be grounded by the second resistance.

3. precharge control circuit as claimed in claim 1, it is characterised in that：The pre-charge module include 3rd resistor and First electric capacity, the first end of the 3rd resistor is connected with the battery pack, the second end and the electricity consumption of the 3rd resistor Equipment and the relay module are connected, and by first capacity earth.

4. precharge control circuit as claimed in claim 3, it is characterised in that：Voltage Uc (the t)=Vb* of first electric capacity (1-exp (- t/r3*c1)), wherein, Vb represents the voltage of the battery pack output, and exp () represents the index letter with e as bottom Number, t represents precharge time, and r3 represents the resistance of the 3rd resistor, and c1 represents the capacitance of first electric capacity, and described first Voltage Uc (t) of electric capacity is the charging voltage of the pre-charge module.

5. precharge control circuit as claimed in claim 1, it is characterised in that：The time delay module includes the second electric capacity and the Four resistance, the first end of second electric capacity is connected with the high pressure detection module, the second end of second electric capacity with it is described Control module is connected, and by the 4th resistance eutral grounding, the time delay of the time delay module is more than or equal to the precharge mould The charging voltage of block reaches the precharge time of the reference value.

6. precharge control circuit as claimed in claim 1, it is characterised in that：The control module includes timer and electronics Switch, the timer includes triggering pin and output pin, and the triggering pin is connected to receive institute with the time delay module Testing result is stated, the output pin is connected with the first end of the electronic switch, the second end ground connection of the electronic switch, institute The 3rd end for stating electronic switch is connected with the relay module.

7. precharge control circuit as claimed in claim 6, it is characterised in that：The relay module includes relay, institute Relay is stated including coil and switch, the first end of the coil is connected with power supply, the second end and the electronics of the coil 3rd end of switch is connected, and the first end of the switch is connected with the battery pack, the second end and the electricity consumption of the switch Equipment and the pre-charge module are connected.

8. precharge control circuit as claimed in claim 7, it is characterised in that：The relay module also includes diode, The anode of the diode is connected with the second end of the coil, the first end phase of the negative electrode of the diode and the coil Even.

9. precharge control circuit as claimed in claim 6, it is characterised in that：The electronic switch is NMOS FETs, The first end of the electronic switch, the second end and the 3rd end correspond respectively to grid, drain electrode and the source of the NMOS FETs Pole.

10. a kind of electric automobile, it is characterised in that：The electric automobile includes pre- as claimed in any one of claims 1-9 wherein Charging control circuit, battery pack and electrical equipment, the battery pack gives the electrical equipment by the precharge control circuit Power supply.