Electric power supply and distribution system for electric vehicle and method for operating electric vehicle power supply system
A dual back-to-back switch unit with microcontroller control optimizes power distribution in electric vehicles, addressing DCDC performance issues by ensuring critical loads receive power during failures, reducing converter size and cost, and enhancing safety and environmental impact.
Patent Information
- Application Number
- CN202380042795.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-05-31
- Filing Date
- 2023-05-29
- Publication Date
- 2025-01-03
AI Technical Summary
The increasing number of electrical components and advanced systems in electric vehicles necessitates higher power requirements, leading to insufficient DCDC performance, which can cause 12V battery failure during driving, affecting safety and service life, and existing power supply systems are oversized and costly.
A dual back-to-back switch unit with microcontroller control is used to manage power distribution between two DC-DC converters, allowing variable loads to be disconnected from one line in case of failure, ensuring critical loads receive power, reducing DC-DC converter rating, and enhancing safety and efficiency.
This solution optimizes power distribution, reduces DC-DC converter size and cost, enhances safety, and minimizes environmental impact by ensuring critical loads receive power during failures, thereby improving vehicle safety and reducing production footprint.
Smart Images
Figure CN119256461A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a power supply and distribution system for an electric vehicle and a method for operating a power supply system for an electric vehicle. More specifically, the present disclosure relates to a power supply and distribution system for an electric vehicle and a method for operating a power supply system for an electric vehicle as defined in the preambles of the independent claims. Background Art
[0002] In all electric and conventional vehicles, electrical ECUs and electrical components (including 12V battery charging) are powered by a 12V alternator or a DC-DC converter, which converts power from the high voltage side (800 / 400 / 48V) to the low voltage side (12V). The alternator and the DCDC (converter) will always be rated for maximum power output. As the automotive industry and almost all OEMs are moving towards increasing levels of vehicle electrification, the number of electrical components in each vehicle will increase. This means an increase in current consumption and higher requirements for the power supply system. In addition, the introduction of different levels of autonomous driving systems or advanced driver assistance systems (ADAS) also increases the requirements for high DCDC performance and power availability. If the power (capacity rate) of the DCDC is insufficient, it will cause the 12V battery to lose power during driving, shortening its service life, or even losing its function in the worst case when the battery is completely exhausted.
[0003] The 12V battery in modern electric vehicles is only used when the vehicle is parked with the DCDC turned off (to use entertainment convenience loads); during vehicle startup and when the DCDC fails to ensure that the vehicle is safely stopped.
[0004] The rated power of a DCDC is always limited by size (due to installation / limited available locations) and cost. In addition, the power of the DCDC should be able to ensure and cover all electrical load consumption during driving under different climate conditions.
[0005] Therefore, the industry needs better vehicle power supply systems that can improve safety while reducing the need for oversized and expensive DC-DC converters. Summary of the invention
[0006] An object of the present disclosure is to mitigate, alleviate or eliminate one or more of the above-mentioned deficiencies and disadvantages recognized in the prior art and to at least solve the above-mentioned problems.
[0007] According to a first aspect, there is provided a power supply and distribution system for an electric vehicle, comprising: a high voltage power supply connected to a first DC-DC converter and a second DC-DC converter, each of the first DC-DC converter and the second DC-DC converter respectively generating a low voltage direct current to a first main power supply line for a first group of critical low voltage equipment and a second main power supply line for a second group of critical low voltage equipment; wherein the first main power supply line and the second main power supply line are connected in parallel to a variable electrical load via a dual back-to-back switch unit, the dual back-to-back switch comprising a first back-to-back switch and a second back-to-back switch, each of the first back-to-back switch and the second back-to-back switch being individually controlled by at least a first microcontroller unit.
[0008] One advantage of this embodiment is that variable electrical loads (including low-voltage devices that are not important for vehicle safety) are concentrated on their own busbar, which can be disconnected in the event of insufficient power (i.e. due to partial battery failure), so that the remaining power can be used for safety-critical low-voltage devices connected to the first and second main power supply lines. The maximum rating of the DC-DC converter can also be reduced thereby. This in turn will reduce the cost and weight of the vehicle, and also reduce the environmental footprint for producing the vehicle.
[0009] However, the dual back-to-back switch can be made of any back-to-back switch, which is composed of two identical or similar elements connected in series to improve fault safety. The simplest back-to-back switch can be made of two simple electromechanical switches connected in series, while a very fast and more advanced back-to-back switch can be made of two MOSFETs connected back-to-back in series. The first back-to-back switch and the second back-to-back switch can be constructed in a variety of ways to achieve the above-mentioned fault safety. However, for the concept of the present disclosure, any back-to-back switch suitable for the rated power of the electric vehicle power supply and distribution system can be used for the first back-to-back switch and the second back-to-back switch, as long as the first back-to-back switch and the second back-to-back switch can be controlled by at least the first microcontroller unit.
[0010] According to some embodiments, the at least first microcontroller unit receives input regarding the power supply availability status of the first and second main power supply lines from the central electronic unit and / or the vehicle control unit, respectively.
[0011] Since variable electrical loads can be connected to a DC-DC converter with capacity at each point in time, the maximum rating of the DC-DC converter can also be reduced. The load control of the prior art cannot perform load control in a controlled and sufficiently fast manner. They can only request a smaller electrical load to limit its current consumption and functionality. It is difficult to judge whether this limitation is successful, and completely disabling the load is not feasible. The solutions for reducing loads in the prior art can neither provide power for critical loads nor handle (use) dual power supply systems in an adequate manner.
[0012] However, the solution disclosed herein can easily move the current consumption of these variable electrical loads between the two supply lines according to the power availability of the DCDC. This will achieve adequate power balancing and better control in the system. In adverse situations such as electrical faults, by reducing or disconnecting the variable electrical loads on the defective supply line, the DCDC will leave more power capacity to power more critical, safety-related electrical loads such as autonomous driving systems, braking and steering functions, which rely solely on power and energy.
[0013] According to some embodiments, a second microcontroller unit is included, wherein the first back-to-back switch is controlled by at least the first microcontroller unit and the second back-to-back switch is controlled by the second microcontroller unit.
[0014] The advantage of this solution is that since the first back-to-back switch and the second back-to-back switch are controlled separately, the redundancy of the power supply and distribution system is higher, which will lead to an increase in the level of automotive safety integrity level (ASIL).
[0015] According to some embodiments, the first microcontroller unit and the second microcontroller unit are built into the dual back-to-back switch unit.
[0016] The advantage of this is that the power supply and distribution system is more robust and durable, and the number of components is reduced. The reduction in the number of components also makes the vehicle easier to assemble, saving time, cost and protecting the environment.
[0017] According to some embodiments, the first back-to-back switch and the second back-to-back switch of the dual back-to-back switch are arranged to meet a high ASIL level.
[0018] According to a second aspect, there is provided a method for operating a power supply system for an electric vehicle according to the first aspect, comprising the following steps: at the at least first microcontroller unit, balancing the load of a variable electric load between a first main power supply line and a second main power supply line. In this way, the maximum rating of the DC-DC converter can be reduced, thereby reducing the cost and weight of the vehicle, and also reducing the environmental footprint for producing the vehicle.
[0019] According to some embodiments, the method comprises the following steps: calculating the power availability from the first DC-DC converter and the second DC-DC converter at at least the first microcontroller unit, and controlling the first back-to-back switch and the second back-to-back switch based on the calculated respective power availability. An advantage of this embodiment is that the optimization effect of power resources is further improved. The maximum rating of the DC-DC converter can be reduced, which in turn reduces the cost and weight of the vehicle, and also reduces the environmental footprint of vehicle production.
[0020] According to some embodiments, the method comprises the step of: at the at least first microcontroller unit, controlling the first back-to-back switch and the second back-to-back switch not to be closed simultaneously. One advantage is that short circuits are avoided in the system.
[0021] According to some embodiments, the method comprises the step of disconnecting the variable electrical load from the failed main power line upon failure of the first main power line or the second main power line. The advantage of this is load optimization, so that safety-critical equipment will be able to use all the remaining power from the failed power line.
[0022] According to some embodiments, the at least first microcontroller unit is arranged to disconnect the variable electric load from the first main power supply line and the second main power supply line when the first main power supply line and / or the second main power supply line fails. An advantage of this embodiment is that the power to the variable electric load is completely cut off, so that safety-critical devices will be able to use all remaining power from the failed first main power supply line and / or the failed second main power supply line.
[0023] The effects and features of the second aspect are largely similar to those of the first aspect described above. The embodiments mentioned with respect to the first aspect are largely compatible with the second aspect.
[0024] The present disclosure will become apparent from the detailed description given below. The detailed description and specific embodiments disclose preferred embodiments of the present disclosure only by way of illustration. According to the guidance in the detailed description, those skilled in the art will appreciate that changes and modifications can be made within the scope of the present disclosure.
[0025] Therefore, it should be understood that the content disclosed herein is not limited to the specific components of the described device or the steps of the described method, because such devices and methods are changeable. It should also be understood that the terms used in this article are only for describing specific embodiments and are not intended to be limiting. It should be noted that the articles "one", "an", "the" and "said" used in the specification and the appended claims are intended to indicate the presence of one or more elements, unless the context clearly indicates otherwise. Therefore, for example, references to "a unit" or "the unit" can include several devices, etc. In addition, the words "comprise", "include", "contain" and similar words do not exclude other elements or steps. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The above and other objects, features, and advantages of the present disclosure will be more fully understood by referring to the following illustrative and non-limiting detailed description of exemplary embodiments of the present disclosure when taken in conjunction with the accompanying drawings.
[0027] Figure 1 The layout of a power supply system according to the prior art is shown.
[0028] Figure 2 A block diagram of a method according to the present disclosure is shown. DETAILED DESCRIPTION
[0029] The present disclosure will now be described with reference to the accompanying drawings, in which preferred exemplary embodiments of the present disclosure are shown. However, the present disclosure may be implemented in other forms and should not be construed as being limited to the embodiments disclosed herein. The disclosed embodiments are provided in order to fully convey the scope of the present disclosure to those skilled in the art.
[0030] Figure 1 The first aspect of the present disclosure is shown, which discloses a power supply and distribution system 1 for an electric vehicle. The power supply and distribution system includes a high voltage power supply 2 connected to a first DC-DC converter DCDC1 and a second DC-DC converter DCDC2, each of which generates low voltage direct current to a first main power supply line PS1 for a first group of critical low voltage devices 5 and a second main power supply line PS2 for a second group of critical low voltage devices 6. The first main power supply line PS1 and the second main power supply line PS2 are connected in parallel to a variable electric load VEL via a dual back-to-back switch unit SW. The dual back-to-back switch SW includes a first back-to-back switch SW1 and a second back-to-back switch SW2, each of which is individually controlled by at least a first microcontroller unit MCU1.
[0031] Figure 1In the embodiment, the first back-to-back switch SW1 and the second back-to-back switch SW2 are composed of an on-off switch connected in parallel with a diode and an identical on-off switch connected in parallel with the diode in series, and the diodes are connected back to back (the directions of the diodes are opposite). However, the double back-to-back switch can be made of any two identical or similar switch elements connected in series to improve the fail-safety of the switch. The simplest back-to-back switch can be made of two simple electromechanical switches connected in series, while a very fast and more advanced back-to-back switch can be made of two MOSFETs connected back to back in series. The first back-to-back switch SW1 and the second back-to-back switch SW2 can be constructed in a variety of ways to achieve the fail-safe performance just described. However, for the concepts proposed in the present disclosure, as long as it can be controlled by at least the first microcontroller unit MCU1, any back-to-back switch with a rated power suitable for the electric vehicle power supply and distribution system can be used for the first back-to-back switch SW1 and the second back-to-back switch SW2.
[0032] like Figure 1 As disclosed in the enlarged ellipse in the figure, variable electrical loads consisting of low-voltage devices that are not critical to vehicle safety are gathered onto their own bus 9, which can be disconnected in the event of insufficient power (e.g. due to a partial battery failure), so that the remaining power can be used for those low-voltage devices that are critical to safety and are connected to the first and second main power supply lines. As a result, the maximum rating of the DC-DC converter can also be reduced. This in turn will reduce the cost and weight of the vehicle, and also reduce the environmental footprint for producing the vehicle. Figure 1 As further shown, the first main power supply line PS1 and the second main power supply line PS2 are each equipped with a 12V backup battery in case of power failure. The first main power supply line PS1 and the second main power supply line PS2 supply power to low voltage devices that are critical to driving the vehicle, while non-critical low voltage devices are connected to the bus 9 of variable electrical loads.
[0033] At least the first microcontroller unit MCU1 receives input from the central electronic unit and / or the vehicle control unit regarding the power supply availability status of the first and second main power supply lines PS1, PS2, respectively.
[0034] The power supply and distribution system 1 further comprises a second microcontroller unit MCU2 , wherein the first back-to-back switch SW1 and the second back-to-back switch SW2 are controlled by said at least first microcontroller unit MCU1 .
[0035] Figure 1In the embodiment, the first microcontroller unit and the second microcontroller unit are built into the dual back-to-back switch unit SW. This makes the dual back-to-back switch unit SW faster and the power supply and distribution system more robust. All switching logic can be implemented in the dual back-to-back switch unit SW. This includes that the unit can be notified of power supply availability and other important data directly from the first main power supply line PS1 and the second main power supply line PS2 for improved control of the first back-to-back switch SW1 and the second back-to-back switch SW2.
[0036] The first back-to-back switch SW1 and the second back-to-back switch SW2 in the double back-to-back switch SW achieve a high ASIL level, for example, by Figure 1 The first back-to-back switch SW1 and the second back-to-back switch SW2 are constructed as shown, that is, using an on-off switch connected in parallel with a diode and an identical on-off switch connected in series with the diode, and the directions of the diodes are opposite (i.e., back to back). However, as a second example, each of the first back-to-back switch SW1 and the second back-to-back switch SW2 can be composed of two MOSFET components connected back to back.
[0037] A second aspect of the present disclosure shows a method for operating an electric vehicle power supply system 1 according to the first aspect, comprising the following steps: S1, balancing the load of a variable electric load VEL between a first main power supply line PS1 and a second main power supply line PS2 at the at least first microcontroller unit MCU1. Thus, the variable electric load VEL can always be connected to the power supply line with the largest excess capacity (power).
[0038] The method further comprises the following steps: S2, calculating power availability from the first DC-DC converter DCDC1 and the second DC-DC converter DCDC2 at at least the first microcontroller unit MCU1, and controlling the first back-to-back switch SW1 and the second back-to-back switch SW2 based on the calculated respective power availability. For example, if the advanced driver assistance system operates on the first main power supply line PS1, so that the first main power supply line PS1 has less excess power than the second main power supply line PS2, the variable electric load VEL will be connected to the second main power supply line PS2 through the power supply and distribution system.
[0039] The method further comprises the following step: S3, controlling the first back-to-back switch SW1 and the second back-to-back switch SW2 not to be closed at the same time at at least the first microcontroller unit MCU1, thereby avoiding a short circuit.
[0040] The method further comprises the following steps: S4, when a fault occurs in the first main power line PS1 or the second main power line PS2, the variable electric load VEL is disconnected from the faulty main power line. Therefore, the safety-critical equipment of the faulty main power line will obtain all available power without having to compete with the variable electric load VEL.
[0041] S5. At least the first microcontroller unit MCU1 is configured to disconnect the variable electric load VEL from the first main power supply line PS1 and the second main power supply line PS2 when a fault occurs in the first main power supply line PS1 and / or the second main power supply line PS2. Since the variable electric load VEL is not critical for driving the vehicle, all remaining power will be reserved for equipment required to drive the vehicle to a safe place on the roadside or in traffic or away from traffic.
[0042] Those skilled in the art will appreciate that the present disclosure is not limited to the above-described embodiments. Those skilled in the art will further appreciate that many variations and modifications may be made within the scope of the appended claims. For example, those skilled in the art will appreciate that the present invention may be extended to have a third main supply line and triple back-to-back switches to further enhance fail-safety. Furthermore, by studying the drawings, the disclosure, and the appended claims, those skilled in the art may understand and implement variations of the disclosed embodiments in practicing the disclosure claimed herein.
Claims
1. A power supply and distribution system (1) for an electric vehicle, comprising: a high voltage power supply (2) connected to a first DC-DC converter (DCDC1) and a second DC-DC converter (DCDC2), each of which generates low voltage direct current to a first main power supply line (PS1) for a first group of critical low voltage devices (DCDC2) and a second main power supply line (PS2) for a second group of critical low voltage devices (5); In which, the first main power supply line (PS1) and the second main power supply line (PS2) are connected in parallel to the variable electric load (VEL) via a dual back-to-back switch unit (SW), and the dual back-to-back switch (SW) includes a first back-to-back switch (SW1) and a second back-to-back switch (SW2), and each of the first back-to-back switch (SW1) and the second back-to-back switch (SW2) is individually controlled by at least a first microcontroller unit (MCU1).
2. The power supply system (1) according to claim 1, wherein: The at least first microcontroller unit (MCU1) receives inputs regarding the power supply availability status of the first main power supply line (PS1) and the second main power supply line (PS2) from the central electronic unit and / or the vehicle control unit, respectively.
3. The power supply system (1) according to claim 1 or 2, further comprising a second microcontroller unit (MCU2), wherein: The first back-to-back switch (SW1) and the second back-to-back switch (SW2) are controlled by the at least first microcontroller unit (MCU1).
4. The power supply system (1) according to any one of the preceding claims, wherein: The first microcontroller unit and the second microcontroller unit are built in the dual back-to-back switch unit (SW).
5. The power supply system (1) according to any one of the preceding claims, wherein: The first back-to-back switch (SW1) and the second back-to-back switch (SW2) in the dual back-to-back switches (SW) meet a high ASIL level.
6. A method for operating a power supply system (1) for an electric vehicle according to any one of the preceding claims, comprising the following steps: (S1): At the at least first microcontroller unit (MCU1), balancing the load of the variable electric load (VEL) between a first main power supply line (PS1) and a second main power supply line (PS2).
7. The method for operating an electric power supply system (1) according to claim 6, further comprising the following steps: (S2): Calculating power availability from the first DC-DC converter (DCDC1) and the second DC-DC converter (DCDC2) at the at least first microcontroller unit (MCU1), and controlling the first back-to-back switch (SW1) and the second back-to-back switch (SW2) based on the corresponding calculated power availability.
8. The method for operating an electric power supply system (1) according to claim 6 or 7, further comprising the following steps: (S3): Controlling the first back-to-back switch (SW1) and the second back-to-back switch (SW2) at the at least first microcontroller unit (MCU1) so as not to be closed at the same time.
9. The method for operating a power supply system (1) according to any one of claims 6 to 8, further comprising the following steps: (S4): When a fault occurs in the first main power supply line (PS1) or the second main power supply line (PS2), the variable electric load (VEL) is disconnected from the faulty main power supply line.
10. Method for operating an electric power supply system (1) according to claim 9, wherein: The at least first microcontroller unit (MCU1) is configured to execute step (S5) to disconnect the variable electric load (VEL) from the first main power line (PS1) and the second main power line (PS2) when a fault occurs in the first main power line (PS1) and / or the second main power line (PS2).