CN115042627A

CN115042627A - Low-voltage dual-power system of electric vehicle and control method

Info

Publication number: CN115042627A
Application number: CN202210870589.5A
Authority: CN
Inventors: 张海珠; 赵家旺; 李振远; 姚胜旺
Original assignee: Beijing Jingwei Hirain Tech Co Ltd
Current assignee: Beijing Jingwei Hirain Tech Co Ltd
Priority date: 2022-07-22
Filing date: 2022-07-22
Publication date: 2022-09-13

Abstract

The present specification discloses an electric vehicle low-voltage dual power supply system and a control method, the system including: the high-voltage power battery is connected with the direct-current voltage conversion module and supplies power to the first low-voltage storage battery, the second low-voltage storage battery and the load; the direct-current voltage conversion module is connected with the power supply coupling control module and used for reducing the output voltage of the high-voltage power battery; the power coupling control module is connected with the first low-voltage storage battery, the second low-voltage storage battery and the safety isolation module and is connected with the load through the safety isolation module, and the power coupling control module is used for carrying out logic judgment according to the acquired element data and the circuit state so as to control the power supply mode of the system; the safety isolation module is used for guaranteeing the safety of a circuit and a load; the load includes a normal load and a safety load, and is a power supply object of the system.

Description

Low-voltage dual-power system of electric vehicle and control method

Technical Field

The invention relates to the technical field of automotive electronics, in particular to a low-voltage dual-power system of an electric vehicle and a control method.

Background

At present, a single power supply network is mostly adopted for supplying power for a low-voltage electrical system in the automobile industry, the power supply stability is poor, or redundant power supply is simply carried out through double power supplies in parallel, the risk of mutual interference exists, active control cannot be realized, and the power supply safety of the whole automobile needs to be improved. The risk resistance of a single power supply network power supply scheme is weak, if a power supply network fails in the running process of a vehicle, all low-voltage systems of the whole vehicle, particularly braking, steering and intelligent driving systems lose energy supply, the vehicle cannot run according to the intention of a driver, accidents can be caused, and the personal and property safety of road participants is seriously influenced.

The dual-power direct parallel power supply scheme can improve the reliability of a low-voltage power supply system theoretically, but because two storage batteries have the defect that voltage difference discharges mutually, interference exists between two paths of outputs, and if one path of the output is in a problem, the normal operation of the whole power supply network is adversely affected, and new risks are brought. Most sensors, actuators and controllers on the current vehicle do not have the coupling control capability of dual power input, and the application range is limited. And other dual power supply schemes are generally complex in circuit, high in cost and high in product realization difficulty, and are not suitable for being applied to vehicles.

Therefore, a low-voltage dual power system and a control method for an electric vehicle are urgently needed to be researched to solve the problem of low-voltage power supply of the electric vehicle.

Disclosure of Invention

The present specification provides an electric vehicle low-voltage dual power supply system and a control method to overcome at least one technical problem in the prior art.

According to a first aspect of embodiments herein, there is provided an electric vehicle low-voltage dual power supply system, comprising: the high-voltage power battery is connected with the direct-current voltage conversion module and used for supplying power to the first low-voltage storage battery, the second low-voltage storage battery and the load; the direct-current voltage conversion module is connected with the power supply coupling control module and is used for reducing the output voltage of the high-voltage power battery; the power supply coupling control module is connected with the first low-voltage storage battery, the second low-voltage storage battery and the safety isolation module and is connected with the load through the safety isolation module, and the power supply coupling control module is used for carrying out logic judgment according to the acquired element data and the circuit state so as to control the power supply mode of the system; the safety isolation module is used for guaranteeing the safety of a circuit and a load; the load comprises a conventional load and a safety load and is a power supply object of the dual-power system; the direct-current voltage conversion module, the first low-voltage battery, the second low-voltage battery, the normal load, and the safety load are grounded.

Optionally, the power coupling control module includes a signal acquisition component, a logic judgment component and an execution component, wherein the signal acquisition component includes a dc voltage conversion module working state acquisition component, a battery state acquisition component and a circuit state acquisition component, the state data acquired by the dc voltage conversion module working state acquisition component includes voltage output, current output, temperature and fault information of the dc voltage conversion module, the state data acquired by the battery state acquisition component includes battery voltage, battery current, battery SOC and battery SOH, and the circuit state acquired by the circuit state acquisition component includes overvoltage, overcurrent and short circuit; the logic judgment component comprises a processor and a memory, the memory is used for storing the state data and the circuit state acquired by the signal acquisition component, and the processor is used for performing calculation processing according to the state data and the circuit state and sending a control instruction to the execution component; the execution assembly comprises a first switch, a second switch, a third switch and a fourth switch, wherein the first switch and the third switch are connected with the direct-current voltage conversion module in a parallel mode respectively, the first switch and the second switch are connected in a series mode and then connected with the first low-voltage storage battery, the third switch and the fourth switch are connected in a series mode and then connected with the second low-voltage storage battery, a leading-out end on a circuit between the first switch and the second switch is connected with the safety isolation module, a leading-out end on a circuit between the third switch and the fourth switch is connected with the safety isolation module, and two leading-out circuits are independent before being connected into the safety isolation module.

Optionally, the dc voltage conversion module includes a first dc voltage converter and a second dc voltage converter, wherein an input end of the first dc voltage converter is connected to the high-voltage power battery, and an output end of the first dc voltage converter is connected to the first switch; the input end of the second direct-current voltage converter is connected with the high-voltage power battery, and the output end of the second direct-current voltage converter is connected with the third switch; the first direct-current voltage converter and the second direct-current voltage converter are independent of each other.

Optionally, the safety isolation module comprises a first safety box, a second safety box and an isolation device, wherein the isolation device is a three-terminal device; one end of the first safety box is connected with a leading-out end on a circuit between the first switch and the second switch, and the other end of the first safety box is connected with the first end of the isolating device; one end of the second fuse box is connected with a leading-out end on a circuit between the third switch and the fourth switch, the other end of the second fuse box is connected with the second end of the isolating device, and the other end of the second fuse box is connected with the conventional load; the second end of the isolating device is connected with the conventional load, and the third end of the isolating device is connected with the safety load; the first switch, the second switch, the first low-voltage storage battery and the first fuse box form a first power supply circuit, the third switch, the fourth switch, the second low-voltage storage battery and the second fuse box form a second power supply circuit, and the circuit state acquisition assembly is used for acquiring the circuit states of the first power supply circuit and the second power supply circuit.

Optionally, the fuse isolation module comprises an isolation device and a third fuse box, wherein the isolation device is a three-terminal device; a first end of the isolating device is connected with a leading-out end on a circuit between the first switch and the second switch, a second end of the isolating device is connected with a leading-out end on a circuit between the third switch and the fourth switch, and a third end of the isolating device is connected with one end of the third fuse box; the other end of the third fuse box is connected with the safety load and the conventional load; the first switch, the second switch and first low-voltage battery constitutes first power supply circuit, the third switch, the fourth switch and second low-voltage battery constitutes second power supply circuit, isolating device and third fuse box constitutes third power supply circuit, circuit state acquisition subassembly is used for gathering first power supply circuit second power supply circuit and third power supply circuit's circuit state.

Optionally, the dc voltage conversion module and the power coupling control module perform status data communication through a local area network of a vehicle-mounted controller.

Optionally, the isolation device employs an ideal diode OR an OR-ing controller OR a power supply multiplexer.

According to a second aspect of embodiments herein, there is provided a control method adapted to be executed on a controller of a low-voltage dual power supply system of an electric vehicle configuring a single dc voltage converter, comprising: under the condition that the system works normally, the first switch, the second switch, the third switch and the fourth switch are kept closed; under the condition that the first low-voltage storage battery has a fault, the second switch is switched off; under the condition that the second low-voltage storage battery has a fault, the fourth switch is switched off; under the condition that the first power supply circuit has a fault, the first switch and the second switch are disconnected; under the condition that the second power supply circuit has a fault, the third switch and the fourth switch are disconnected; in case of a failure of the direct voltage converter, the first switch and the third switch are opened.

According to a third aspect of embodiments herein, there is provided a control method adapted to be executed on a controller of a low-voltage dual power supply system of an electric vehicle configured with dual dc voltage converters, comprising: under the condition that the system works normally, the first switch, the second switch, the third switch and the fourth switch are kept closed; under the condition that the first low-voltage storage battery has a fault, the second switch is switched off; under the condition that the second low-voltage storage battery has a fault, the fourth switch is switched off; under the condition that the first power supply circuit has a fault, the first switch and the second switch are disconnected; under the condition that the second power supply circuit has a fault, the third switch and the fourth switch are disconnected; under the condition that the first direct current voltage converter fails, the first switch is switched off; in the event of a failure of the second direct voltage converter, the third switch is opened.

Optionally, in the case that only a single fuse box is configured in the electric vehicle low-voltage dual power supply system, and in the case that the third power supply circuit fails, the first switch, the second switch, the third switch and the fourth switch are opened.

The beneficial effects of the embodiment of the specification are as follows:

the embodiment of the specification provides a low-voltage dual-power supply system and a control method of an electric vehicle, the low-voltage dual-power supply system which is not interfered with each other and is convenient to switch is realized through a power coupling control module, the system utilizes two independent sets of low-voltage storage batteries and a high-voltage power battery to supply power for a load, the power supply reliability of a safety load is guaranteed, the structure is simple, the corresponding control method is easy to realize, the connection between a fault element and the system can be effectively cut off when a component fails, and compared with the traditional low-voltage single-power supply system, the system has few additional parts, and on the premise of not greatly improving the system cost, the defects that the single power supply is weak in risk resistance, the dual-power supplies are directly connected in parallel to supply power and are poor in economical efficiency of a complex redundancy scheme in the prior art are overcome. Through the application of the system, the stability and the reliability of a vehicle low-voltage power supply network can be greatly improved, and the running safety of the vehicle is further ensured.

The innovation points of the embodiment of the specification comprise:

1. in the embodiment of the present description, in the dual power supply system, currents output by the dc voltage conversion module, the first low-voltage battery, and the second low-voltage battery are integrated after being transmitted to the isolation device through the first power supply circuit and the second power supply circuit, and then output to the safety load.

2. In the embodiment of the specification, the active control of the four protection switches in the power coupling control module can actively process the fault on the premise of meeting the power supply requirement of the low-voltage system of the vehicle, so that secondary damage is avoided, and the method is one of the innovation points of the embodiment of the specification.

3. In the embodiment of the specification, in the low-voltage dual-power system of the electric vehicle, considering that most of sensors, controllers and actuators in the current vehicle system do not have dual-power input coupling control capability, an isolating device is added between a power output and a load, the system requirement can be met on the premise of not modifying the current sensors, controllers and actuators, the applicability of the embodiment of the specification is improved, the modification cost is reduced, the isolating device is introduced, the mutual interference of currents supplied to a safety load by two power supply circuits is avoided, adverse effects such as circulation and the like are eliminated, the safety and the usability of the safety load and the dual-power system are ensured, and the low-voltage dual-power system is one of innovation points of the embodiment of the specification.

Drawings

In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present disclosure, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a low-voltage dual power supply system of an electric vehicle according to an embodiment of the present disclosure;

fig. 2 is a schematic structural diagram of a low-voltage dual power supply system of an electric vehicle according to an embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of a low-voltage dual power supply system of an electric vehicle according to an embodiment of the present disclosure;

fig. 4 is a schematic structural diagram of a low-voltage dual power supply system of an electric vehicle according to an embodiment of the present disclosure.

Detailed Description

The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure, and it is obvious that the embodiments described are only a part of the embodiments of the present disclosure, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive effort based on the embodiments of the present invention, are within the scope of the present invention.

It should be noted that the terms "including" and "having" and any variations thereof in the embodiments of the present specification and the drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.

The embodiment of the specification discloses an electric vehicle low-voltage dual power supply system and a control method, which are respectively described in detail below.

Example one

Fig. 1 is a schematic structural diagram of a low-voltage dual power supply system of an electric vehicle according to an embodiment of the present disclosure. As shown in fig. 1, an electric vehicle low-voltage dual power supply system includes: the system comprises a high-voltage power battery 110, a direct-current voltage conversion module 120, a power coupling control module 130, a first low-voltage storage battery 140, a second low-voltage storage battery 150, an insurance isolation module 160 and a load 170, wherein the high-voltage power battery 110 is connected with the direct-current voltage conversion module 120 and is used for supplying power to the first low-voltage storage battery 140, the second low-voltage storage battery 150 and the load 170.

The dc voltage conversion module 120 is connected to the power coupling control module 130, and is configured to step down the output voltage of the high voltage power battery 110.

The power coupling control module 130 is connected to the first low-voltage battery 140, the second low-voltage battery 150, the safety isolation module 160, and the load 170 through the safety isolation module 160, and the power coupling control module 130 is configured to perform logic judgment according to the collected component data and the circuit state to control a power supply mode of the system.

In a specific embodiment, the power coupling control module 130 includes a signal collecting component 132, a logic determining component 134, and an executing component 136, where the signal collecting component 132 includes a dc voltage converting module operating state collecting component, a battery state collecting component, and a circuit state collecting component. The state data acquired by the working state acquisition assembly of the direct-current voltage conversion module comprises voltage output, current output, temperature and fault information of the direct-current voltage conversion module, the state data acquired by the storage battery state acquisition assembly comprises battery voltage, battery current, battery SOC and battery SOH, and the circuit state acquired by the circuit state acquisition assembly comprises overvoltage, overcurrent and short circuit.

Such signal acquisition components may be implemented using sensors of the corresponding physical quantity type in conjunction with ASIC application specific integrated circuits or power management specific chips.

The circuit state acquisition assembly comprises a voltage sensor, a current sensor and a corresponding processing circuit.

The logic judgment component 134 includes a processor and a memory, the memory is used for storing the state data and the circuit state acquired by the signal acquisition component, and the processor is used for performing calculation processing according to the state data and the circuit state and sending a control instruction to the execution component.

The logic judgment component can use a special power management chip and is responsible for storing the acquired system state data, performing calculation processing according to the working state of the system and sending a control instruction to the execution component.

The executing component 136 includes a first switch 1362, a second switch 1364, a third switch 1366 and a fourth switch 1368, wherein the first switch 1362 and the third switch 1366 are respectively connected to the dc-to-dc voltage converting module 120 in parallel, the first switch 1362 and the second switch 1364 are connected in series and then connected to the first low-voltage battery 140, the third switch 1366 and the fourth switch 1368 are connected in series and then connected to the second low-voltage battery 150, an outgoing end of a circuit between the first switch 1362 and the second switch 1364 is connected to the safety isolating module 160, an outgoing end of a circuit between the third switch 1366 and the fourth switch 1368 is connected to the safety isolating module 160, and two outgoing circuits are independent before being connected to the safety isolating module.

The four switches can realize corresponding functions by using a back-to-back connection mode of MOSFET transistors, can also realize the function of controlling the on-off of a circuit by using a relay or a contact switch, and can also realize the same functions by using other electronic elements and combinations thereof.

The safety isolation module 160 is used for ensuring the safety of the circuit and the load.

The load 170 includes a normal load 174 and a safety load 172, which are power supply objects of a dual power supply system.

The load is a power supply object of the dual power supply system and is divided into a conventional load and a safety load. And (3) conventional loading: loads that do not directly cause vehicle accidents if a failure occurs, such as: door and window systems, lighting systems, air conditioning systems, and the like. Safe load: closely related to the driving safety of vehicles, if a failure occurs, the load directly causing an accident, such as: braking system, a steering system, an intelligent driving system and the like. In order to ensure the safety of the vehicle under any working condition and avoid vehicle accidents caused by power supply system faults, a dual-power supply design must be carried out on a safety load.

The storage battery is a component for storing and providing electric energy in the low-voltage dual-power system, serves as an auxiliary power supply component of the circuit, is used for smoothing and moderating current impact in the electric system through flexible charging and discharging, and assists the direct-current voltage conversion module to supply power to the circuit. When the total power consumption of the load does not exceed the power supply capacity of a direct current voltage conversion module (DC-DC), the storage battery receives a part of electric quantity output by the DC-DC for storage; when the total power consumption of the load is too large and exceeds the power supply capacity of the DC-DC, the storage battery and the DC-DC supply power to the load connected behind the circuit together. When the DC-DC stops working, the storage battery discharges to supply power to a load of the circuit; when the DC-DC recovers to normal operation from the stop operation state, the storage battery stops discharging, simultaneously charges in a constant voltage current limiting mode, and then returns to and maintains a floating charge state.

From the system connection, the first low-voltage storage battery and the second low-voltage storage battery are independent from each other and do not interfere with each other, so that the adverse effect on one of the first low-voltage storage battery and the whole power supply system when the other one fails is avoided.

The dc voltage conversion module 120, the first low-voltage battery 140, the second low-voltage battery 150, the normal load 174, and the safety load 172 are grounded.

In one embodiment, the dc voltage conversion module 120 and the power coupling control module 130 communicate status data via an on-board controller area network.

The working state of the direct current voltage conversion module CAN be directly acquired by a sensor and then transmitted to the power coupling control module for processing, and CAN also be transmitted to the power coupling control module by a controller of the direct current voltage conversion module through a vehicle-mounted Controller Area Network (CAN) network in a communication manner.

Fig. 2 is a schematic structural diagram of a low-voltage dual power supply system of an electric vehicle according to an embodiment of the present disclosure. As shown in fig. 2, in a specific implementation, the safety isolation module 160 includes a first safety box 162, a second safety box 164, and an isolation device 166, wherein the isolation device 166 is a three-terminal device; one end of the first fuse box 162 is connected to a terminal on the circuit between the first switch 1362 and the second switch 1364, and the other end of the first fuse box 162 is connected to the first end of the isolating device 166; one end of the second fuse box 164 is connected to a terminal of the circuit between the third switch 1366 and the fourth switch 1368, the other end of the second fuse box 164 is connected to the second end of the isolating device 166, and the other end of the second fuse box 164 is connected to the normal load 174; a second end of the isolation device 166 is connected to the normal load 174, and a third end of the isolation device 166 is connected to the safety load 172.

The fuse box is a fuse element in a dual power supply system circuit, mainly comprises a series of connecting circuits and a load fuse, and automatically fuses to ensure the safety of the circuit when the circuit has faults of overload, short circuit and the like; when the circuit fault is eliminated, the power supply is automatically switched on and recovered.

From system connection, the first fuse box and the second fuse box are mutually independent and do not interfere with each other, the safety of the circuit where the first fuse box and the second fuse box are located is respectively and independently guaranteed, and adverse effects on the other and the whole power supply system when one works or fails are avoided.

The first switch 1362, the second switch 1364, the first low-voltage battery 140 and the first fuse box 162 form a first power supply circuit, the third switch 1366, the fourth switch 1368, the second low-voltage battery 150 and the second fuse box 164 form a second power supply circuit, and the circuit state collecting assembly is used for collecting the circuit states of the first power supply circuit and the second power supply circuit.

The isolation device is an isolation component among the first power supply circuit, the second power supply circuit and the safety load, the first power supply circuit, the second power supply circuit and the safety load are connected, current is input to the isolation device by the first power supply circuit and the second power supply circuit when the isolation device works normally, and the isolation device outputs the current to the safety load after processing.

The introduction of the isolating device avoids mutual interference of currents which are simultaneously supplied to the safety load by the two power supply circuits, eliminates adverse effects such as circulating current and the like, and ensures the safety and the availability of the safety load and the dual-power system.

In a specific implementation, the isolation device employs ideal diodes OR an OR-ing controller OR a power supply multiplexer.

Based on the structure of the dual power supply system, a control method is provided, which is suitable for being executed on a controller of a low-voltage dual power supply system of an electric vehicle with a single direct-current voltage converter, and comprises the following steps:

and S10, keeping the first switch, the second switch, the third switch and the fourth switch closed under the condition that the system works normally.

When the total power consumption of the load does not exceed the DC-DC power supply capacity, the DC-DC supplies all load current, and meanwhile, the storage battery is subjected to supplementary charging to keep the electric quantity of the storage battery sufficient.

When the total power consumption of the load exceeds the DC-DC power supply capacity, the first low-voltage storage battery and the second low-voltage storage battery start to discharge outwards, and the DC-DC and the first low-voltage storage battery simultaneously supply power for the first power supply circuit. The DC-DC and the second low-voltage battery simultaneously supply power to the second power supply circuit.

When the power consumption of the load fluctuates greatly, the voltage and current fluctuation in the dual-power-supply system can be smoothed through flexible charging and discharging of the first low-voltage storage battery and the second low-voltage storage battery, and the damage to electric parts and the load is avoided.

If a fault occurs during vehicle operation, the control strategy for a particular fault condition is as follows.

And S21, opening the second switch when the first low-voltage storage battery has a fault.

If the first low-voltage storage battery has faults in the working process of the vehicle, the faults comprise overvoltage, undervoltage, short circuit, open circuit and the like. The working state of the first low-voltage storage battery is collected in real time by a signal collection assembly of a Power Net Control Module (Power Net Control Module), and the fault of the first low-voltage storage battery is detected through logic judgment processing, so that the first low-voltage storage battery needs to be isolated from a Power supply system, and the Power supply of a load is ensured. And the Power supply coupling Control Module (Power Net Control Module) controls the second switch to be disconnected, so that the first low-voltage storage battery is disconnected from the Power supply system, and the influence of the failure component on the Power supply system is avoided. The first switch, the third switch and the fourth switch are kept closed, and the DC-DC can continuously supply power to the safety load through the first power supply circuit; the DC-DC and the second low-voltage storage battery can continuously supply power for the conventional load and the safety load through the second power supply circuit; meanwhile, the DC-DC can supplement and charge the second low-voltage storage battery, so that the electric quantity of the second low-voltage storage battery is kept sufficient. Under this operating mode, safe load and ordinary load all can obtain lasting electric quantity supply, have avoided single battery inefficacy direct initiation accident, and all functions of vehicle are not influenced.

And S22, turning off the fourth switch when the second low-voltage storage battery has a fault.

If the second low-voltage storage battery has faults in the working process of the vehicle, the faults comprise overvoltage, undervoltage, short circuit, open circuit and the like. And a signal acquisition component of a Power supply coupling Control Module (Power Net Control Module) acquires the working state of the second low-voltage storage battery in real time, detects the fault of the second low-voltage storage battery through logic judgment processing, and needs to isolate the second low-voltage storage battery from a Power supply system and ensure the Power supply of a load. And the Power supply coupling Control Module (Power Net Control Module) controls the fourth switch to be switched on and off, so that the second low-voltage storage battery is disconnected from the Power supply system, and the influence of the failure component on the Power supply system is avoided. The first switch, the second switch and the third switch are kept closed, and the DC-DC and the first low-voltage storage battery can continue to continuously supply power for the safety load through the first power supply circuit; the DC-DC can continuously supply power for the conventional load and the safety load through the second power supply circuit; meanwhile, the DC-DC can supplement charging to the first low-voltage storage battery, and the electric quantity of the first low-voltage storage battery is kept sufficient. Under this operating mode, safe load and ordinary load all can obtain lasting electric quantity supply, have avoided single battery inefficacy direct initiation accident, and all functions of vehicle are all not influenced.

And S23, under the condition that the first power supply circuit has a fault, the first switch and the second switch are opened.

If the first power supply circuit fails, such as a short circuit or an open circuit, during operation of the vehicle. A signal acquisition component of a Power supply coupling Control Module (Power Net Control Module) acquires the working state of a first circuit in real time, and detects the fault of the first circuit through logic judgment processing, so that the fault of the first circuit needs to be isolated from a Power supply system, and the Power supply of a load is ensured. The Power supply coupling Control Module (Power Net Control Module) controls the first switch and the second switch to be disconnected, the first Power supply circuit is isolated from the load, the failed component is effectively isolated, and adverse effects on the Power supply system can be avoided. The third switch and the fourth switch are kept closed, the normal load and the safe load can be continuously supplied through the DC-DC and the second low-voltage storage battery, and meanwhile the DC-DC can charge the second low-voltage storage battery. Under this operating mode, safe load and ordinary load all can obtain lasting electric quantity supply, have avoided single battery inefficacy direct initiation accident, and all functions of vehicle are all not influenced.

And S24, opening the third switch and the fourth switch under the condition that the second power supply circuit has a fault.

If the second power supply circuit fails during operation of the vehicle. And a signal acquisition component of a Power network Control Module (Power Net Control Module) acquires the working state of the second Power supply circuit in real time, detects the fault of the second Power supply circuit through logic judgment processing, and needs to isolate the second Power supply circuit from a Power system and ensure the Power supply of a load. And the Power supply coupling Control Module (Power Net Control Module) controls the third switch and the fourth switch to be disconnected, the connection between the second Power supply circuit and the load is isolated, the failed component is effectively isolated, and the adverse effect of the failed component on a Power supply system can be avoided. The first switch and the second switch are kept closed, the safety load can be continuously supplied with power through the DC-DC and the first low-voltage storage battery, and meanwhile the DC-DC can charge the first low-voltage storage battery. The conventional load is unpowered at this time. Under the working condition, the safety load can be continuously supplied with electric quantity, and accidents caused by the fact that a single storage battery is invalid are avoided.

And S25, opening the first switch and the third switch under the condition that the direct current voltage converter has a fault.

If the direct current voltage conversion module DC-DC fails during the working process of the vehicle, such as: high voltage input failure, low voltage output failure, inability to start, etc. And a signal acquisition component of a Power network Control Module (Power Net Control Module) acquires the working state of the DC-DC in real time, and detects the DC-DC fault through logic judgment processing, so that the DC-DC fault needs to be isolated from a Power system, and continuous Power supply of a load is ensured. The power coupling control module immediately controls the first switch and the third switch to be disconnected, so that the connection between the DC-DC and the power supply system is disconnected, and the influence of a failure component on the power supply system is avoided. And the Power supply coupling Control Module (Power Net Control Module) controls the second switch and the fourth switch to be kept closed, and the first low-voltage storage battery and the second low-voltage storage battery continue to supply Power to the load.

And the second switch and the fourth switch are in a closed state in the normal working process, so that no power interruption exists in the switching process, and the safety and the stability of the power consumption of the load can be well ensured.

Before the residual electric quantity of the first low-voltage storage battery and the residual electric quantity of the second low-voltage storage battery are exhausted, the short-time power supply of the safety load can be realized, the safety load is guaranteed not to lose control capability due to sudden energy supply loss, and the safety load system can take safety measures as soon as possible before the electric quantity of the storage batteries is exhausted under the control of the whole vehicle, such as parking by the side, so that accidents caused by the fact that DC-DC fails are avoided.

The control method of the dual power supply system of the electric vehicle according to the first embodiment is summarized as table 1.

Table 1 dual power supply system control method of embodiment one

In this embodiment, after the current output by the dc voltage conversion module and the first and second low-voltage batteries is transmitted to the isolation device through the first and second power supply circuits and integrated, the current is output to the safety load, and when the above components and circuits fail at the same time, it can be ensured that the safety load is supplied with continuous power. Compared with a single power supply system, the power supply stability of the safety load is greatly improved, and accidents caused by direct faults of a low-voltage power supply system are avoided.

In the first embodiment, when the DCDC fails, the normal load and the safety load can only maintain the short-time power supply, which is a weak link of the first embodiment. The present specification has other embodiments, which can eliminate the influence of the weak link on the power supply stability.

Example two

Fig. 3 is a schematic structural diagram of a low-voltage dual power supply system of an electric vehicle according to an embodiment of the present disclosure. On the basis of embodiment 1, a DC-DC is added between the high-voltage power battery and the power coupling control module.

As shown in fig. 3, in an embodiment, the dc voltage conversion module 120 includes a first dc voltage converter 122 and a second dc voltage converter 124, wherein an input terminal of the first dc voltage converter 122 is connected to the high-voltage power battery 110, and an output terminal of the first dc voltage converter 122 is connected to the first switch 1362; the input end of the second dc voltage converter 124 is connected to the high voltage power battery 110, and the output end of the second dc voltage converter 124 is connected to the third switch 1366; the first dc voltage converter 122 and the second dc voltage converter 124 are independent of each other.

Two DC-DC voltage converters are arranged between the high-voltage power battery and the power coupling module, wherein the first DC-DC is responsible for converting high-voltage direct current output by the high-voltage power battery into low-voltage direct current according to the requirement of a first power supply circuit of a low-voltage dual-power system and supplying the low-voltage direct current to a safety load and a first low-voltage storage battery. The second DC-DC is another voltage conversion module which is responsible for converting the high-voltage direct current output by the high-voltage power battery into low-voltage direct current according to the requirement of a second power supply circuit of the low-voltage dual power supply system and supplying the low-voltage direct current to a safety load, a common load and a second low-voltage storage battery. The first DC-DC and the second DC-DC are main power supply components of the low-voltage dual power supply system. When the first DC-DC or the second DC-DC works normally, the load current is mainly supplied by the DC-DC, and meanwhile, the storage battery is subjected to supplementary charging, so that the storage battery can keep sufficient electric quantity.

And the first DC-DC and the second DC-DC are mutually independent and do not interfere with each other from the system connection, so that the adverse influence on the other and the whole power supply system when one fails is avoided.

Based on the dual power supply system of the second embodiment, a control method is provided, which is suitable for being executed on a controller of a low-voltage dual power supply system of an electric vehicle configured with dual direct-current voltage converters, and includes:

When the low-voltage dual-Power system works normally and all the components have no faults, the Power supply coupling Control Module (Power Net Control Module) controls the first switch, the second switch, the third switch and the fourth switch to be closed. At this time, the first DC-DC and the second DC-DC collectively serve as a main power supply means, and the first low-voltage battery and the second low-voltage battery serve as an auxiliary power supply means. The 4 power supply sources automatically coordinate to work according to the power consumption requirements of the safe load and the common load and the load ratio among the 4 power supply sources.

When the power consumption of the conventional load does not exceed the power supply capacity of the second DC-DC, the second DC-DC supplies all the current of the conventional load, simultaneously supplies power to the safety load according to the requirement of the safety load, and carries out supplementary charging on the second low-voltage storage battery to keep the electric quantity of the storage battery sufficient. And when the total power consumption of the safe load and the conventional load does not exceed the sum of the power supply capacities of the first DC-DC and the second DC-DC, supplying the full load power demand by the first DC-DC and the second DC-DC.

When the total power consumption of the load exceeds the total DC-DC power supply capacity, the first low-voltage storage battery and the second low-voltage storage battery start to discharge outwards, and the DC-DC and the first low-voltage storage battery simultaneously supply power for the first power supply circuit. The DC-DC and the second low-voltage battery simultaneously supply power to the second power supply circuit.

S25, when the first dc voltage converter fails, the first switch is turned off.

If the first DC-DC fails during the operation of the vehicle, such as: high voltage input failure, low voltage output failure, inability to start, etc. And a signal acquisition component of a Power supply coupling Control Module (Power Net Control Module) acquires the working state of the first DC-DC in real time, detects the first DC-DC fault through logic judgment processing, and needs to isolate the first DC-DC fault from a Power supply system and ensure continuous Power supply of a load. The power coupling control module immediately controls the first switch to be disconnected, the first DC-DC is disconnected with the power supply system, and the influence of the failure component on the power supply system is avoided. And the Power supply coupling Control Module (Power Net Control Module) controls the third switch, the second switch and the fourth switch to be kept closed, and the second DC-DC, the first low-voltage storage battery and the second low-voltage storage battery continue to supply Power to the load. When the load works normally, the second switch, the third switch and the fourth switch are in a closed state, so that no power interruption exists in the switching process, and the safety and the stability of the power consumption of the load can be well ensured. In this case, the second DC-DC works continuously, so that the safe load and the conventional load can be ensured to supply power continuously.

S26, opening the third switch when the second dc voltage converter fails.

If the second DC-DC fails during the operation of the vehicle, such as: high voltage input failure, low voltage output failure, inability to start, etc. And a signal acquisition component of a Power supply coupling Control Module (Power Net Control Module) acquires the working state of the second DC-DC in real time, and detects the second DC-DC fault through logic judgment processing, wherein the second DC-DC fault needs to be isolated from a Power supply system, and continuous Power supply of a load is ensured. The power coupling control module immediately controls the third switch to be disconnected, the second DC-DC is disconnected with the power supply system, and the influence of the failure component on the power supply system is avoided. And the Power supply coupling Control Module (Power Net Control Module) controls the first switch, the second switch and the fourth switch to be kept closed, and the first DC-DC, the first low-voltage storage battery and the second low-voltage storage battery continue to supply Power to the load. When the switch is in a normal working process, the first switch, the second switch and the fourth switch are in a closed state, so that no power supply interruption exists in the switching process, and the safety and the stability of the power consumption of the load can be well guaranteed. Under the condition, the first DC-DC continuously works, and the continuous power supply of the safety load can be ensured. And before the residual electric quantity of the second low-voltage storage battery is exhausted, the short-time power supply of the conventional load can be realized.

The control method of the dual power supply system of the electric vehicle of the second embodiment is summarized as table 2.

Table 2 dual power supply system control method of the second embodiment

Through the arrangement of the double direct-current voltage converters, compared with the first embodiment, the stability and the reliability of power supply of the power supply system are improved, but the complexity and the cost of the system are improved.

In the second embodiment, the power supply stability and reliability of the power supply system are high, but all power supply devices adopt a double backup mode, the complexity and cost of the system are high, and especially, the wiring harness from the power supply to the actuator end adopts the double redundancy of the circuit 1 and the circuit 2, so that the wiring harness layout of the whole vehicle is complex, and the number of the wiring harnesses is large. Therefore, on the basis of the second embodiment, the circuit 1 and the circuit 2 are combined to form the scheme of the third embodiment, so that the whole vehicle wiring can be simplified to a greater extent on the premise of unobvious reduction of the system reliability, and the wire harness cost is reduced.

EXAMPLE III

Fig. 4 is a schematic structural diagram of a low-voltage dual power supply system of an electric vehicle according to an embodiment of the present disclosure. Compared with the second embodiment, in the second embodiment, the fuse boxes of the first power supply circuit and the second power supply circuit are adjusted to the isolation device and then combined, and meanwhile, the line connection between the isolation device and the load is combined into one path. The isolating device is an isolating part among the first power supply circuit, the second power supply circuit and the fuse box, the first power supply circuit, the second power supply circuit and the fuse box are connected, the first power supply circuit and the second power supply circuit input current to the isolating device simultaneously when the isolating device works normally, and the isolating device outputs the current to a load after processing. The introduction of the isolating device avoids mutual interference of currents supplied to the load by the two power supply circuits at the same time, eliminates adverse effects such as circulating current and the like, and ensures the safety and the availability of the load and the dual-power system.

As shown in fig. 4, in a specific implementation, the fuse isolation module 160 includes an isolation device 166 and a third fuse box 168, wherein the isolation device 166 is a three-terminal device; a first end of the isolation device 166 is connected to a terminal of the circuit between the first switch 1362 and the second switch 1364, a second end of the isolation device 166 is connected to a terminal of the circuit between the third switch 1366 and the fourth switch 1368, and a third end of the isolation device 166 is connected to one end of the third fuse box 168; the other end of the third fuse box 168 is connected to the safety load 172 and the normal load 174.

The first switch 1362, the second switch 1364 and the first low-voltage battery 140 form a first power supply circuit, the third switch 1366, the fourth switch 1368 and the second low-voltage battery 150 form a second power supply circuit, the isolating device 166 and the third fuse box 168 form a third power supply circuit, and the circuit state collecting assembly is used for collecting the circuit states of the first power supply circuit, the second power supply circuit and the third power supply circuit.

Based on the dual power supply system of the embodiment, a control method is provided, which is suitable for being executed on a controller of a low-voltage dual power supply system of an electric vehicle configured with dual direct-current voltage converters, and comprises the following steps:

And S22, opening the fourth switch when the second low-voltage storage battery has a fault.

And S23, opening the first switch when the first direct current voltage converter has a fault.

S24, opening the third switch when the second dc voltage converter fails.

And S25, under the condition that the first power supply circuit has a fault, the first switch and the second switch are opened.

If the first power supply circuit fails (short circuit/open circuit, etc.) during operation of the vehicle. The signal acquisition component of the Power network Control Module (Power Net Control Module) acquires the working state of the first Power supply circuit in real time, detects the fault of the first Power supply circuit through logic judgment processing, and needs to isolate the fault from the Power supply system, and ensures the Power supply of a load. The Power supply coupling Control Module (Power Net Control Module) controls the first switch and the second switch to be disconnected, the first Power supply circuit is isolated from the load, the failed component is effectively isolated, and adverse effects on the Power supply system can be avoided. The third switch and the fourth switch are kept closed, the normal load and the safety load can be continuously supplied with power through the second DC-DC and the second low-voltage storage battery, and meanwhile the second DC-DC can charge the second low-voltage storage battery. Under the working condition, the safe load and the conventional load can be continuously supplied with electric quantity, so that accidents caused by single circuit failure are avoided, and all functions of the vehicle are not influenced.

And S26, opening the third switch and the fourth switch under the condition that the second power supply circuit has a fault.

If the second power supply circuit fails (short circuit/open circuit, etc.) during operation of the vehicle. And a signal acquisition component of a Power network Control Module (Power Net Control Module) acquires the working state of the second Power supply circuit in real time, detects the fault of the second Power supply circuit through logic judgment processing, and needs to isolate the second Power supply circuit from a Power system and ensure the Power supply of a load. The Power supply coupling Control Module (Power Net Control Module) controls the third switch and the fourth switch to be disconnected, the second Power supply circuit is isolated from the load, the failed part is effectively isolated, and adverse effects on the Power supply system can be avoided. The first switch and the second switch are kept closed, the safety load can be continuously supplied with power through the first DC-DC and the first low-voltage storage battery, and meanwhile the first DC-DC can charge the first low-voltage storage battery. The conventional load is unpowered at this time. Under the working condition, the safe load and the conventional load can be continuously supplied with electric quantity, so that accidents caused by single circuit failure are avoided, and all functions of the vehicle are not influenced.

And S27, opening the first switch, the second switch, the third switch and the fourth switch when the third power supply circuit has a fault.

If the third power supply circuit fails (short circuit/open circuit, etc.) during operation of the vehicle. At this time, the connection between the load and the power supply is failed, and the system cannot operate.

The control method of the dual power supply system of the electric vehicle of the third embodiment is summarized as table 3.

Table 3 dual power supply system control method of the third embodiment

In this embodiment, in the dual power supply system, currents output by the first DC-DC and the first low-voltage battery, and currents output by the second DC-DC and the second low-voltage battery are respectively integrated after being transmitted to the isolating device in the third power supply circuit through the first power supply circuit and the second power supply circuit, and then are output to the load.

The scheme disclosed by the specification has various embodiments, and on the basis of the first embodiment, the second embodiment and the third embodiment can be realized in an expanded manner by adding components and adjusting circuit connection, so that different circuit power supply stabilities are achieved. Table 4 shows the results of comparison of examples 1 to 3.

TABLE 4 comparison of advantages and disadvantages of examples 1, 2 and 3

As shown in table 4, the solutions of the three embodiments have advantages and disadvantages under the trade-off between the complexity and the cost of the solution, but compared with the single power source or the simple parallel power source in the prior art, the embodiments of the present disclosure make an inventive contribution to the solution of the low-voltage power supply problem of the electric vehicle.

To sum up, the embodiment of the present specification provides an electric vehicle low-voltage dual power supply system and a control method, the system has a simple structure, the control method is easy to implement, on the premise of lower cost, an original single power supply system is easy to improve, the technical problems in the prior art that a single power supply has weak risk resistance, mutual interference of direct parallel power supply and poor economical efficiency of a complex redundancy scheme are solved, the stability and reliability of a vehicle low-voltage power supply network can be effectively improved, and further the safety of vehicle operation is ensured.

Those of ordinary skill in the art will understand that: the figures are merely schematic representations of one embodiment, and the blocks or flow diagrams in the figures are not necessarily required to practice the present invention.

Those of ordinary skill in the art will understand that: modules in the devices in the embodiments may be distributed in the devices in the embodiments according to the description of the embodiments, or may be located in one or more devices different from the embodiments with corresponding changes. The modules of the above embodiments may be combined into one module, or further split into multiple sub-modules.

Claims

1. An electric vehicle low-voltage dual power supply system, comprising:

the high-voltage power battery, the direct-current voltage conversion module, the power coupling control module, the first low-voltage storage battery, the second low-voltage storage battery, the safety isolation module and the load, wherein

The high-voltage power battery is connected with the direct-current voltage conversion module and used for supplying power to the first low-voltage storage battery, the second low-voltage storage battery and the load;

the direct-current voltage conversion module is connected with the power supply coupling control module and is used for reducing the output voltage of the high-voltage power battery;

the power supply coupling control module is connected with the first low-voltage storage battery, the second low-voltage storage battery and the safety isolation module and is connected with the load through the safety isolation module, and the power supply coupling control module is used for carrying out logic judgment according to the acquired element data and the circuit state so as to control the power supply mode of the system;

the safety isolation module is used for guaranteeing the safety of a circuit and a load;

the load comprises a conventional load and a safety load and is a power supply object of the dual-power system;

the direct-current voltage conversion module, the first low-voltage battery, the second low-voltage battery, the normal load, and the safety load are grounded.

2. The system of claim 1, wherein the power coupling control module comprises a signal acquisition component, a logic determination component, and an execution component, wherein

The signal acquisition assembly comprises a working state acquisition assembly of a direct current voltage conversion module, a storage battery state acquisition assembly and a circuit state acquisition assembly, state data acquired by the working state acquisition assembly of the direct current voltage conversion module comprises voltage output, current output, temperature and fault information of the direct current voltage conversion module, the state data acquired by the storage battery state acquisition assembly comprises battery voltage, battery current, battery SOC and battery SOH, and the circuit state acquired by the circuit state acquisition assembly comprises overvoltage, overcurrent and short circuit;

the logic judgment component comprises a processor and a memory, the memory is used for storing the state data and the circuit state acquired by the signal acquisition component, and the processor is used for performing calculation processing according to the state data and the circuit state and sending a control instruction to the execution component;

the execution assembly comprises a first switch, a second switch, a third switch and a fourth switch, wherein the first switch and the third switch are connected with the direct-current voltage conversion module in a parallel mode respectively, the first switch and the second switch are connected in a series mode and then connected with the first low-voltage storage battery, the third switch and the fourth switch are connected in a series mode and then connected with the second low-voltage storage battery, a leading-out end on a circuit between the first switch and the second switch is connected with the safety isolation module, a leading-out end on a circuit between the third switch and the fourth switch is connected with the safety isolation module, and two leading-out circuits are independent before being connected into the safety isolation module.

3. The system of claim 2, wherein the dc voltage conversion module comprises a first dc voltage converter and a second dc voltage converter, wherein

The input end of the first direct-current voltage converter is connected with the high-voltage power battery, and the output end of the first direct-current voltage converter is connected with the first switch;

the input end of the second direct-current voltage converter is connected with the high-voltage power battery, and the output end of the second direct-current voltage converter is connected with the third switch;

the first direct-current voltage converter and the second direct-current voltage converter are independent of each other.

4. A system according to claim 2 or 3, wherein the fuse isolation module comprises a first fuse block, a second fuse block and an isolation device, wherein

The isolation device is a three-terminal device;

one end of the first safety box is connected with a leading-out end on a circuit between the first switch and the second switch, and the other end of the first safety box is connected with the first end of the isolating device;

one end of the second fuse box is connected with a leading-out end on a circuit between the third switch and the fourth switch, the other end of the second fuse box is connected with the second end of the isolating device, and the other end of the second fuse box is connected with the conventional load;

the second end of the isolating device is connected with the conventional load, and the third end of the isolating device is connected with the safety load;

the first switch, the second switch, the first low-voltage storage battery and the first fuse box form a first power supply circuit, the third switch, the fourth switch, the second low-voltage storage battery and the second fuse box form a second power supply circuit, and the circuit state acquisition assembly is used for acquiring the circuit states of the first power supply circuit and the second power supply circuit.

5. The system of claim 3, wherein the fused isolation module comprises an isolation device and a third fuse box, wherein

The isolation device is a three-terminal device;

a first end of the isolating device is connected with a leading-out end on a circuit between the first switch and the second switch, a second end of the isolating device is connected with a leading-out end on a circuit between the third switch and the fourth switch, and a third end of the isolating device is connected with one end of the third fuse box;

the other end of the third fuse box is connected with the safety load and the conventional load;

the first switch, the second switch and first low-voltage battery constitutes first power supply circuit, the third switch, the fourth switch and second low-voltage battery constitutes second power supply circuit, isolating device and third fuse box constitutes third power supply circuit, circuit state acquisition subassembly is used for gathering first power supply circuit second power supply circuit and third power supply circuit's circuit state.

6. The system of claim 1, comprising:

and the direct-current voltage conversion module and the power supply coupling control module carry out state data communication through a vehicle-mounted controller local area network.

7. The system of claim 5, comprising:

the isolation device employs ideal diodes OR-ing controllers OR power multiplexers.

8. A control method adapted to be executed on a controller of an electric vehicle low-voltage dual power supply system configured with a single dc voltage converter, comprising:

under the condition that the system works normally, the first switch, the second switch, the third switch and the fourth switch are kept closed;

under the condition that the first low-voltage storage battery has a fault, the second switch is switched off;

under the condition that the second low-voltage storage battery has a fault, the fourth switch is switched off;

under the condition that the first power supply circuit has a fault, the first switch and the second switch are disconnected;

under the condition that the second power supply circuit has a fault, opening the third switch and the fourth switch;

in case of a failure of the direct voltage converter, the first switch and the third switch are opened.

9. A control method adapted to be executed on a controller of a dual dc voltage converter configured electric vehicle low voltage dual power supply system, comprising:

under the condition that the second power supply circuit has a fault, the third switch and the fourth switch are disconnected;

under the condition that the first direct-current voltage converter fails, the first switch is switched off;

in the event of a failure of the second direct voltage converter, the third switch is opened.

10. The method of claim 9, further comprising:

in the case that the electric vehicle low-voltage dual power supply system is only provided with a single fuse box, and in the case that the third power supply circuit has a fault, the first switch, the second switch, the third switch and the fourth switch are opened.