Low-voltage power supply circuit and carrier

Abstract

According to the low-voltage power supply circuit and the carrier, an overvoltage protection circuit is arranged in the low-voltage power supply circuit, so that overvoltage of a low-voltage power supply in the use and operation process of an electric automobile is prevented, and low-voltage electric appliances of the whole automobile are effectively protected from being damaged by high voltage. Even if the low-voltage power supply of the whole vehicle is reversely connected, the over-voltage protection circuit cannot work due to incorrect voltage bias of three poles of a triode in the over-voltage protection circuit, so that the low-voltage power supply of the whole vehicle does not work, and the overall safety is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicles, and more specifically, to a low-voltage power supply circuit and a vehicle. Background Art

[0002] As new energy vehicles are increasingly used, the safety protection functions of new energy vehicles are also being improved. Among them, the low-voltage overvoltage protection function of the vehicle's low-voltage electrical appliances is also being continuously improved. At present, the battery of electric vehicles is charged by the DCDC of the whole vehicle, thereby realizing over-voltage and under-voltage protection of the battery.

[0003] However, the above technical solution has the following problems: when the DCDC of the electric vehicle is damaged or not connected to the low-voltage power supply, the low-voltage power supply of the entire vehicle may require an external power supply. When the external power supply is connected, improper overvoltage operation may occur, resulting in overvoltage causing damage to the low-voltage electrical appliances of the electric vehicle, which has high maintenance costs and may even cause the entire vehicle to catch fire or be scrapped. Summary of the invention

[0004] The present invention overcomes the technical problem of insufficient protection of low-voltage electrical appliances of a vehicle in the prior art, and provides a low-voltage power supply circuit and a vehicle, in the hope of solving the problems existing in the prior art.

[0005] In order to solve the above technical problems, the present invention provides a low-voltage power supply circuit on one hand:

[0006] A low voltage power supply circuit comprises an overvoltage protection circuit, a power supply and a switch circuit;

[0007] The power supply is connected to the overvoltage protection circuit, and the overvoltage protection circuit is connected to the switch circuit;

[0008] The overvoltage protection circuit controls the switch circuit to be turned on when the power supply voltage does not exceed the set range, and to be turned off when the power supply voltage exceeds the set range.

[0009] The overvoltage protection circuit can effectively protect the input overvoltage on the low-voltage power supply, including overvoltage caused by improper equipment or human operation, and transient overvoltage of surge. It can effectively protect the low-voltage electrical appliances and load circuits of the entire vehicle, cut off the low-voltage power supply circuit in advance, and avoid damage to the voltage appliances of the entire vehicle due to overvoltage.

[0010] A further technical solution is that the overvoltage protection circuit includes a voltage regulator, a bias resistor, an isolation resistor, and a triode:

[0011] The switch circuit includes a relay;

[0012] The relay coil end is connected to a first end and a second end of an overvoltage protection circuit;

[0013] The normally closed contact of the relay is connected to the low-voltage electrical appliance of the vehicle;

[0014] The second end of the voltage regulator tube is connected to the first end of the bias resistor and the first end of the isolation resistor;

[0015] The second end of the bias resistor is connected to the collector of the transistor, and one end of the collector of the transistor is grounded;

[0016] The second end of the isolation resistor is connected to the base of the transistor.

[0017] The working principle of the overvoltage protection circuit is that when the power supply output voltage is within the normal range, the Zener tube is not broken down, and the B pole of the transistor is at a low potential, so that the transistor is turned on and power is supplied through circuit control; when the vehicle power supply output voltage exceeds the set voltage of the Zener tube, the Zener tube is turned on, the B pole of the transistor is at a high potential, the transistor is cut off, and the power is cut off through circuit control to realize overvoltage detection and protection functions.

[0018] A further technical solution is that the overvoltage protection circuit is specifically a comparison detection circuit;

[0019] The comparison detection circuit controls the switch circuit to open or close according to the power supply voltage.

[0020] A further technical solution is that the power supply includes a DC-DC converter and / or a battery;

[0021] Any one of the DC-DC converter and the battery is connected to the switch circuit.

[0022] When the output voltage of the vehicle battery or DC-DC converter is within the normal range, the Zener diode is not broken down, the B pole of the transistor is at a low point, and the low-voltage power supply is turned on through the relay coil, transistor, bias resistor and isolation resistor, the C pole of the transistor is at a low potential, and the power supply is normal; when the output voltage of the vehicle battery or DC-DC converter exceeds the set voltage of the Zener diode, the Zener diode is turned on, the B pole of the transistor is at a high potential, the transistor is cut off, the C pole of the transistor is at a high potential, the power supply is disconnected from the low-voltage power supply circuit, and the overvoltage detection and protection function is realized.

[0023] A further technical solution is that the low voltage power supply circuit further includes an LC filter circuit;

[0024] The first end of the LC filter circuit is connected to the positive pole of the power supply, and the second end of the LC filter circuit is connected to the first end of the overvoltage protection circuit and the first end of the switch circuit.

[0025] The LC filter circuit utilizes the suppression effect of large inductance L on current mutation and the suppression effect of capacitor C on voltage mutation to make the power waveform smoother and eliminate power interference. The present invention also provides a vehicle, including the low-voltage power supply circuit and vehicle low-voltage electrical appliances as described above;

[0026] The vehicle low-voltage electrical appliances are powered by a low-voltage power supply circuit.

[0027] Compared with the prior art, the present invention has at least the following beneficial effects: the present invention prevents the overvoltage of the low-voltage power supply during the use and operation of the electric vehicle by setting an overvoltage protection circuit in the low-voltage power supply circuit, effectively protecting the low-voltage electrical appliances of the entire vehicle from damage due to high voltage. Even when the low-voltage power supply of the entire vehicle is reversely connected, the transistor in the overvoltage protection circuit cannot work due to the incorrect voltage bias of the triode, thereby making the low-voltage power supply of the entire vehicle inoperative, further improving the overall safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the connection relationship of the low-voltage power supply circuit;

[0029] Figure 2 This is a schematic diagram of a low voltage power supply circuit;

[0030] Figure 3 It is a voltage comparison detection circuit;

[0031] In the figure, 1-DC-DC converter, 2-battery, 3-switching circuit, 4-overvoltage protection circuit, 5-electric carrier low-voltage electrical appliance, 6-LC filter circuit. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] Embodiment 1

[0034] A low voltage power supply circuit, see Figure 1 , Figure 2 , including an overvoltage protection circuit 4, a power supply, a switch circuit 3, and an LC filter circuit 6;

[0035] The power supply is connected to the overvoltage protection circuit 4, and the overvoltage protection circuit 4 is connected to the switch circuit 3;

[0036] The overvoltage protection circuit 4 controls the switch circuit 3 to be turned on when the power supply voltage does not exceed the set range, and to be turned off when the power supply voltage exceeds the set range.

[0037] It should be noted that the overvoltage protection circuit 4 may be an overvoltage protection circuit 4 composed of a voltage regulator ZD1, a bias resistor R1, an isolation resistor R2, and a transistor Q1, or may be a voltage comparison detection circuit.

[0038] In this embodiment, the overvoltage protection circuit 4 includes a voltage regulator, a bias resistor, an isolation resistor, and a triode:

[0039] The switch circuit 3 includes a relay;

[0040] The relay coil end is connected to the first end and the second end of the overvoltage protection circuit 4;

[0041] The normally closed contact of the relay is connected to the vehicle low-voltage electrical appliance.

[0042] It should be noted that the transistor Q1 and the relay K1 can be replaced by IGBT and MOS tube;

[0043] The second end of the voltage regulator tube is connected to the first end of the bias resistor and the first end of the isolation resistor;

[0044] The second end of the bias resistor is connected to the collector of the transistor, and one end of the collector of the transistor is grounded;

[0045] The second end of the isolation resistor is connected to the base of the transistor.

[0046] The positive pole of the power supply is connected to the first end of the LC filter circuit 6, and the second end of the LC filter circuit 6 is connected to the first end of the overvoltage protection circuit 4 and the first end of the switch circuit 3; the LC filter circuit 6 uses the large inductance L to suppress current mutations, and the capacitor C to suppress voltage mutations, so as to make the power supply waveform smoother and eliminate power supply interference. The first end of the overvoltage protection circuit 4 is connected, that is, the power supply is connected to the voltage regulator tube, and the voltage regulator tube can detect the power supply voltage. When the voltage exceeds the set voltage, the voltage regulator tube is broken down, and the overvoltage protection circuit 4 controls the switch circuit 3 to disconnect.

[0047] When the overvoltage protection circuit 4 is a comparison detection circuit, refer to Figure 3 The specific wiring is as follows: the comparison detection circuit is composed of a voltage regulator tube ZD2, a bias resistor R5, a voltage sampling resistor R3 and a voltage dividing resistor R4, a comparator U1B, and a driver integrated block U2A; the voltage regulator tube ZD2 and the bias resistor R5 form a reference voltage for comparison, which is connected to the (+) end of the comparator U1B; the voltage sampling resistor R3 and the voltage dividing resistor R4 form a voltage dividing sampling circuit, which is connected to the (-) end of the comparator U1B; the output end of the comparator U1B is connected to the input end of the driver integrated block U2A.

[0048] One end of the voltage sampling resistor R3 replaces the first end of the voltage regulator tube ZD1, the first end of the voltage regulator tube ZD2 is connected to the vehicle power supply, and the output end of the driving integrated block U2A is connected to the second end of the relay coil.

[0049] When the power supply voltage is normal, the output of the voltage-dividing sampling circuit composed of the voltage sampling resistor R3 and the voltage-dividing resistor R4 is lower than the reference voltage compared by the voltage-stabilizing tube ZD2 and the bias resistor R5, the output end of the comparator U1B outputs a high level, which is inverted by the driving integrated block U2A and outputs a low level, the relay is energized, the relay contacts are closed, and the low-voltage electrical appliances of the electric vehicle of the whole vehicle are powered on; when the power supply voltage is too high, the output of the voltage-dividing sampling circuit composed of the voltage sampling resistor R3 and the voltage-dividing resistor R4 exceeds the reference voltage compared by the voltage-stabilizing tube ZD2 and the bias resistor R5, the output end of the comparator U1B outputs a low level, which is inverted by the driving integrated block U2A and outputs a high level, the relay is not energized, the relay contacts are disconnected, and the low-voltage electrical appliances of the electric vehicle of the whole vehicle are powered off.

[0050] The power supply includes a DC-DC converter 1 and / or a battery 2. In the present embodiment, the power supply includes a DC-DC converter 1 and a battery 2, wherein the DC-DC converter 1 is connected to the battery 2 to charge the battery 2.

[0051] Any one of the DC-DC converter 1 and the battery 2 is connected to the switch circuit 3. Specifically, the overvoltage protection circuit 4 and the switch circuit 3 are connected between the positive pole of the battery 2 and the low-voltage bus of the low-voltage distribution box between the vehicle's low-voltage electrical equipment. The first end of the overvoltage protection circuit 4 and the first end of the switch circuit 3 are connected to the second end of the LC filter circuit 6; the second end (output control end) of the overvoltage protection circuit 4 is directly connected to the coil of the relay driving the switch circuit 3 to control the relay's attraction or disconnection; the second end of the switch circuit 3 is connected to the vehicle's low-voltage electrical equipment to protect the overvoltage protection device of all low-voltage electrical equipment.

[0052] In this embodiment, the vehicle low-voltage electrical appliances include VCU, MCU, BMS, BCM and other electrical appliances, which are directly connected to the low-voltage power supply through the switch circuit 3. Among them, VCU is the vehicle controller, MCU is the motor controller, BMS is the battery management system, and BCM is the body controller.

[0053] When in use, when the electric vehicle is in normal condition, the vehicle battery 2 supplies low-voltage electricity to the electric vehicle, and the DC-DC converter 1 charges the electric vehicle battery 2; but when the battery 2 of the electric vehicle is low on power, the battery 2 is charged by an external charger; or when the vehicle has no battery 2 and the vehicle needs to be debugged with low-voltage electricity, an external low-voltage power supply is required for the vehicle. At this time, it is possible that an excessively high low-voltage power supply is connected to the low-voltage power supply of the vehicle.

[0054] When an excessively high low-voltage power supply is input to the low-voltage power supply of the entire vehicle, the overvoltage protection circuit 4 detects that the voltage exceeds the set voltage value (the set voltage value is lower than the maximum withstand voltage value of the VCU, MCU, BMS, BCM and other low-voltage electrical appliances of the electric vehicle, and higher than the normal working voltage value of the battery 2), the voltage regulator ZD1 is turned on, the transistor Q1 is turned off, and the relay K1 in the switch circuit 3 is disconnected, thereby protecting the low-voltage electrical appliances from overvoltage; when the low-voltage power supply input to the entire vehicle does not exceed the voltage value set by the overvoltage protection circuit 4, the voltage regulator ZD1 is turned off, the transistor Q1 is turned on, the relay K1 in the switch circuit 3 is closed, and the low-voltage line is powered normally.

[0055] Embodiment 2

[0056] A vehicle, comprising the low-voltage power supply circuit and vehicle low-voltage electrical appliances as described above;

[0057] The vehicle low-voltage electrical appliances are powered by a low-voltage power supply circuit.

[0058] Although the present invention is described herein with reference to the illustrative embodiments of the present invention, it should be understood that those skilled in the art can design many other modifications and implementations, which will fall within the scope and spirit of the principles disclosed in the present application. More specifically, within the scope disclosed in the present application, multiple variations and improvements can be made to the components and / or layout of the subject combination layout. In addition to the variations and improvements made to the components and / or layout, other uses will also be apparent to those skilled in the art.

Claims

1. A low voltage power supply circuit, characterized in that: Including overvoltage protection circuit, power supply, switching circuit; The power supply is connected to the overvoltage protection circuit, and the overvoltage protection circuit is connected to the switch circuit; The overvoltage protection circuit controls the switch circuit to be turned on when the power supply voltage does not exceed the set range, and to be turned off when the power supply voltage exceeds the set range.

2. A low voltage power supply circuit as claimed in claim 1, characterized in that: The overvoltage protection circuit includes a voltage regulator, a bias resistor, an isolation resistor, and a triode: The switch circuit includes a relay; The relay coil end is connected to a first end and a second end of an overvoltage protection circuit; The normally closed contact of the relay is connected to the low-voltage electrical appliance of the vehicle; The second end of the voltage regulator tube is connected to the first end of the bias resistor and the first end of the isolation resistor; The second end of the bias resistor is connected to the collector of the transistor, and one end of the collector of the transistor is grounded; The second end of the isolation resistor is connected to the base of the transistor.

3. A low voltage power supply circuit as claimed in claim 1, characterized in that: The overvoltage protection circuit is specifically a comparison detection circuit; The comparison detection circuit controls the switch circuit to open or close according to the power supply voltage.

4. A low voltage power supply circuit as claimed in claim 1, characterized in that: The power supply includes a DC-DC converter and / or a battery; Any one of the DC-DC converter and the battery is connected to the switch circuit.

5. A low voltage power supply circuit as claimed in claim 1, characterized in that: Also includes, LC filter circuit; The first end of the LC filter circuit is connected to the positive pole of the power supply, and the second end of the LC filter circuit is connected to the first end of the overvoltage protection circuit and the first end of the switch circuit.

6. A carrier, comprising the low-voltage power supply circuit and the carrier low-voltage electrical appliance according to any one of claims 1 to 5; The vehicle low-voltage electrical appliances are powered by a low-voltage power supply circuit.

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