Ground offset identification apparatus and vehicle electrical system comprising same

Abstract

The present invention relates to a ground offset identification apparatus for a vehicle electrical system, and a vehicle electrical system comprising this apparatus. The apparatus comprises: a voltage stabilizing circuit, which is configured to output a constant standard voltage V0 on the basis of a first reference ground GND_LV; and a controller, a ground terminal thereof being connected to a second ground point, so as to provide the controller with a second reference ground voltage GND_HV, the controller being configured to collect in real time a voltage difference V_OUT of the output voltage of the voltage stabilizing circuit relative to the second reference ground GND_HV, and identify whether a ground offset is present in the vehicle electrical system on the basis of the voltage difference V_OUT and the standard voltage V0. The ground offset identification apparatus can quickly and accurately calculate a ground offset voltage, and promptly terminate the operation of a load when the ground offset exceeds an allowed threshold value, thereby effectively preventing damage to circuit elements due to an excessively large ground offset.

Description

[0001] Ground offset identification apparatus and vehicle electrical system comprising same

[0002] Technical Field

[0003] The present invention relates to the field of vehicle electrical systems; more specifically, the present invention relates to a ground offset identification apparatus for a vehicle electrical system, and a vehicle electrical system comprising this apparatus.

[0004] Background Art

[0005] With the development of new energy vehicle technology, the number of power supply networks on a whole vehicle has increased. For example, for a mild hybrid system vehicle model, with a low-voltage onboard power grid (12 V) of a system as a basis, an additional high-voltage onboard power grid (48 V) is added, to reduce fuel consumption of the whole vehicle. Generally, the low-voltage onboard power grid and the high-voltage onboard power grid are both jointly connected to a converter, and this converter is responsible for converting the high voltage of 48 V to the low voltage of 12 V. Such a design can effectively combine functions of a starter motor and a generator of a vehicle, improving energy utilization efficiency and vehicle performance.

[0006] To save on connecting lines in the vehicle electrical system, most vehicles at present use a grounding circuit connection configuration; that is, a ground wire of a power source or a load is grounded nearby at a metal part of the vehicle frame, and metal bodies of the engine and the automobile chassis are used as a common channel (also called “vehicle body ground”) that connects various negative terminals. However, such a connection method has a notable problem: namely, a design of a common ground between low-voltage and high-voltage power grids may produce the phenomenon of ground offset (i.e. a difference is present between the ground potentials of the two onboard power grids). Such ground offset may result in elements in the system circuits being subjected to inappropriate voltages, giving rise to overvoltage or undervoltage conditions. In extreme cases, an excessively large ground offset further causes circuit damage or unintentional malfunctioning, thereby affecting the reliability and safety of the whole vehicle. In addition, due to differences in the quality and positions of whole vehicle ground points, the problem of ground offset may occur unpredictable presenting additional challenges for vehicle maintenance and fault diagnosis.

[0007] Summary of the Invention

[0008] The present invention intends to solve the problem of ground offset caused by a design of a common ground between low-voltage and high-voltage onboard power grids in a vehicle (particularly a mild hybrid vehicle), and accordingly provides an effective ground offset identification apparatus for a vehicle electrical system.

[0009] One aspect of the present invention provides a ground offset identification apparatus for a vehicle electrical system, the vehicle electrical system comprising multiple onboard power grids, negative terminals of the multiple onboard power grids being respectively connected to a vehicle body ground via different ground points, and the ground offset identification apparatus being configured to identify a ground offset voltage between the ground points, wherein the ground offset identification apparatus comprises: a voltage stabilizing circuit, a ground terminal of the voltage stabilizing circuit being connected to a first ground point between a first onboard power grid of the multiple onboard power grids and the vehicle body ground, so as to provide the voltage stabilizing circuit with a first reference ground voltage GND_LV, wherein the voltage stabilizing circuit is configured to output a constant standard voltage VO on the basis of the first reference ground voltage GND_LV; and a controller, a ground terminal of the controller being connected to a second ground point between a second onboard power grid of the multiple onboard power grids and the vehicle body ground, so as to provide the controller with a second reference ground voltage GND_HV, wherein the controller comprises a sampling port that is connected to an output of the voltage stabilizing circuit, the controller being configured to collect in real time a voltage difference V_OUT of the output voltage of the voltage stabilizing circuit relative to the second reference ground GND_HV, with the aid of the sampling port, and identify whether a ground offset is present in the vehicle electrical system on the basis of the voltage difference V_OUT and the standard voltage VO of the voltage stabilizing circuit.

[0010] The controller is further configured to: calculate an offset amount AV between the voltage difference V_OUT and the standard voltage VO of the voltage stabilizing circuit; and judge whether the offset amount AV is greater than a set threshold value, wherein if the offset amount AV is greater than the set threshold value, determine that a ground offset is present in the vehicle electrical system.

[0011] The controller is further configured to: send an alarm signal to a whole vehicle controller of the vehicle when it is determined that a ground offset is present in the vehicle electrical system.

[0012] A drive circuit is provided in the vehicle electrical system, and the drive circuit is configured to drive at least one load of the vehicle under the control of the controller.

[0013] The controller is further configured to: control the drive circuit to terminate the operation of the at least one load when it is determined that a ground offset is present in the vehicle electrical system.

[0014] Another aspect of the present invention further provides a vehicle electrical system, wherein the system comprises: multiple onboard power grids, negative terminals of the multiple onboard power grids being respectively connected to a vehicle body ground via different ground points; and the ground offset identification apparatus described above. 2024P00286WG

[0015] 4

[0016] The vehicle electrical system comprises a mild hybrid system of a vehicle, wherein the mild hybrid system comprises a first onboard power grid and a second onboard power grid that are respectively provided with different power supply sources.

[0017] A drive circuit is provided in the second onboard power grid, and the drive circuit is configured to drive at least one load of the vehicle under the control of the controller.

[0018] The at least one load comprises a BSG electric machine that is arranged in the mild hybrid system.

[0019] The first onboard power grid comprises a 12 V storage battery, and the second onboard power grid comprises a 48 V power source.

[0020] The advantages of the ground offset identification apparatus according to the present invention lie in that the circuit design thereof is simple and efficient. By means of integrating an appropriate algorithm logic, the ground offset identification apparatus can quickly and accurately calculate a ground offset voltage, and promptly terminate the operation of a load (particularly the BSG electric machine) and related diagnostic work of a circuit when the ground offset exceeds the allowed threshold value, thereby effectively preventing circuit element damage and fault misreporting due to an excessively large ground offset. In addition, the ground offset identification apparatus does not require additional high-cost isolation chips, and improves system reliability and stability while reducing costs. Therefore, the ground offset identification apparatus not only increases the safety and reliability of the 48 V mild hybrid system (particularly a BSG electric machine thereof), but also simplifies fault detection and maintenance workflows, providing a more economical and efficient solution for vehicle manufacturers and users.

[0021] Brief Description of the Drawings

[0022] By incorporating accompanying drawings of the present text and subsequent particular embodiments that are used together with the drawings for explaining certain principles of the present invention, other features and advantages of the method of the present invention will become clear or will be explained in more detail. 2024P00286WG

[0023] 5

[0024] Fig. 1 shows a structural schematic drawing of a ground offset identification apparatus for a vehicle electrical system according to an exemplary embodiment of the present invention.

[0025] Fig. 2 shows a schematic drawing of the ground offset identification apparatus in Fig. 1 being used to identify a ground offset scenario in a vehicle electrical system.

[0026] Detailed Description of Embodiments

[0027] A ground offset identification apparatus for a vehicle electrical system according to the present invention is described below with reference to the accompanying drawings and by way of embodiments. In the following description, many specific details are expounded for a person skilled in the art to more fully understand the present invention. However, it will be obvious to a person skilled in the art that the present invention may be implemented without having some of these specific details. Conversely, any combination of the following features and elements may be considered for implementing the present invention, regardless of whether they relate to different embodiments. Therefore, the following various aspects, features, embodiments and advantages are only provided for descriptive purposes and should not be viewed as elementary or a limitation to the claims.

[0028] In existing vehicle electrical systems, due to differences in the quality and positions of ground points (i.e. “grounding points”) in various onboard power grids, a phenomenon of ground offset may occur between reference grounds in the different onboard power grids. Taking a 48 V mild hybrid system as an example, if a phenomenon of poor grounding occurs in a power grid, for example, corrosion of a ground line connector results in increased resistance, and the ground line is not installed securely, these factors all result in poor contact of the grounding, such that current attempts to pass through another circuit, thereby causing the phenomenon of ground offset to occur. That is, an electric potential difference between a low-voltage ground GND_LV and a high-voltage ground GND_HV may exceed a predetermined safe range; this type of scenario is also called an excessively large ground offset. An excessively large ground offset results in chips on many drive circuits supplying overvoltage or undervoltage power due to the excessively large 2024P00286WG

[0029] 6 ground offset when a low-voltage 12 V power source individually supplies power when a high-voltage power source has not yet been powered on.

[0030] To overcome the above problem, the present invention proposes a ground offset identification apparatus for a vehicle electrical system; the apparatus introduces a voltage stabilizer with a low-voltage ground GND_LV as a reference ground and uses an ADC port of an MCU (with a high-voltage ground GND_HV as a reference ground) to sample output thereof in real time, thereby calculating a ground offset voltage. According to the magnitude of this ground offset voltage, whether an electric motor is allowed to operate can be determined, so as to protect a circuit against the effects of an excessively large ground offset.

[0031] Specifically, this voltage stabilizer can provide a standard voltage VO, such as 5 V, in a scenario in which the low-voltage ground GND_LV is a reference. The output of the voltage stabilizer is connected to the sampling port ADC of the MCU to perform voltage sampling, and, by conversion with software, a voltage difference value V_OUT between the ADC port voltage relative to the reference ground (i.e. GND_HV) of the MCU can be obtained, and the ground offset scenario can be accurately monitored on the basis of a difference between the voltage difference value V_OUT and the 5 V standard voltage VO of the voltage stabilizer.

[0032] Fig. 1 shows a structural schematic drawing of a ground offset identification apparatus for a vehicle electrical system according to an exemplary embodiment of the present invention. The vehicle electrical system may comprise multiple onboard power grids, negative terminals of these power grids being respectively connected to a vehicle body ground via different ground points, and the ground offset identification apparatus aiming to identify a ground offset voltage between the ground points. Below, the working principle of this ground offset identification apparatus is presented in detail by taking a 48 V mild hybrid system as an example.

[0033] Firstly, this 48 V mild hybrid system may comprise two power supply networks, such as a 12 V low-voltage onboard power grid and a 48 V high-voltage onboard power grid, and these two power grids respectively have a low-voltage ground GND_LV and a high-voltage ground GND_HV. In particular, a belt-driven starter / generator integrated machine (abbreviated as “BSG” electric machine) may be provided in the high-voltage onboard power grid, and this BSG electric machine, for example, may run under the drive of a drive circuit that includes a converter.

[0034] This ground offset identification apparatus in particular can introduce a voltage stabilizing circuit, a ground terminal of the voltage stabilizing circuit being connected to a first ground point between the low-voltage onboard power grid and the vehicle body ground, for example, so as to provide the voltage stabilizing circuit with a first reference ground voltage GND_LV. The voltage stabilizing circuit can output a constant standard voltage VO in a scenario in which this first reference ground voltage GND_LV is a reference.

[0035] The output of the voltage stabilizing circuit is transferred to the controller MCU, and the ground terminal of the controller is connected to a second ground point between the high-voltage onboard power grid and the vehicle body ground, so as to provide this controller with a second reference ground voltage GND_HV. The controller comprises a sampling port that is connected to the voltage stabilizing circuit; with the aid of this sampling port, the controller can collect in real time a voltage difference V_OUT of the output voltage of the voltage stabilizing circuit relative to the second reference ground GND_HV, and identify whether a ground offset is present in the vehicle electrical system on the basis of this voltage difference V_OUT and the standard voltage VO of the voltage stabilizing circuit.

[0036] A specific computational logic executed in the controller comprises:

[0037] - calculating an offset amount AV between this voltage difference V_OUT and the standard voltage VO of the voltage stabilizing circuit, i.e. AV = VO - V_OUT, the offset amount AV being a ground offset between two reference grounds; and

[0038] - judging whether the offset amount AV is greater than a set threshold value, wherein if the offset amount AV is greater than the set threshold value, determining that a ground offset is present in the vehicle electrical system. 2024P00286WG

[0039] 8

[0040] Fig. 2 shows a schematic drawing of the ground offset identification apparatus in Fig. 1 being used to identify a ground offset scenario in a vehicle electrical system. For example, when it is determined that a ground offset is present in the vehicle electrical system, such as when a ground offset value AV calculated by a controller is greater than an allowed threshold value, the controller can send an alarm signal to a whole vehicle controller VCU of the vehicle. Additionally or alternatively, when it is determined that a ground offset is present in the vehicle electrical system, the controller can control a drive circuit to terminate the operation of the BSG electric machine, to prevent elements in a circuit from experiencing unnecessary overvoltage or undervoltage damage.

[0041] Another exemplary embodiment of the present invention further provides a vehicle electrical system, this system comprising multiple onboard power grids, wherein negative terminals of the onboard power grids are respectively connected to a vehicle body ground via different ground points. In addition, this system may further comprise the ground offset identification apparatus described herein. The vehicle electrical system, for example, may be a mild hybrid system of a vehicle, and this system particularly may be used for providing the vehicle with auxiliary motive power, and with starter and generator functions, and with a power recovery function, etc.

[0042] Specifically, this mild hybrid system may be provided with a 48 V power supply network and a 12 V power supply network; this 48 V power supply network may supply a BSG electric machine with power, and this electric motor may act as an electric motor, and also may act as a generator. When acting as an electric motor, the electric machine drives the vehicle to move with the aid of the power of a 48 V battery pack, and in addition, the electric machine may further provide motive power to an air conditioner compressor and a cooling water pump which consume a lot of power. When acting as a generator, the electric machine recovers kinetic energy from braking, converts the kinetic energy into electrical energy and returns the electrical energy to a storage battery. The 12 V low-voltage power supply network can be used for supplying power to a low-voltage load (such as a lighting lamp, an electronic valve, etc.) inside the vehicle.

[0043] The advantages of the ground offset identification apparatus according to the 2024P00286WG

[0044] 9 present invention lie in that the circuit design thereof is simple and efficient. By means of integrating an appropriate algorithm logic, the ground offset identification apparatus can quickly and accurately calculate a ground offset voltage, and promptly terminate the operation of a load (particularly the BSG electric machine) and diagnostic work of a related circuit when the ground offset exceeds the allowed threshold value, thereby effectively preventing circuit element damage and fault misreporting due to an excessively large ground offset. In addition, the ground offset identification apparatus does not require additional high-cost isolation chips, and improves system reliability and stability while reducing costs. Therefore, the ground offset identification apparatus not only increases the safety and reliability of the 48 V mild hybrid system (particularly a BSG electric machine thereof), but also simplifies fault detection and maintenance workflows, providing a more economical and efficient solution for vehicle manufacturers and users.

[0045] In the present invention, the term “connection” means “electrical connection” or “communication connection”. In addition, regarding the use of terms such as “include” and “comprise”, as well as indicating having elements directly or explicitly expressed in the description and the claims, the technical solutions of the present application also do not exclude having other elements that are not directly or explicitly expressed.

[0046] In the present invention, a person skilled in the art will understand that the disclosed system may be implemented in other ways. The system embodiments described above are merely schematic; for example, the partition of the modules is merely a partition of logical function, and, when actually implemented, another mode of partition may be used, such as the functions of multiple modules being combined or a function of a certain module being further broken down. The modules in the embodiments of the present invention may be integrated into one processing unit, or each module may be physically independent, or two or more modules may be integrated into one unit.

[0047] Although the present invention is disclosed above as preferred embodiments, the present invention is not limited to this. Various alterations and modifications made without departing from the spirit and scope of the present invention shall all fall within the scope of protection of the present invention, and therefore the scope of protection of the present invention shall be defined by the claims.

Claims

Claims1 . A ground offset identification apparatus for a vehicle electrical system, the vehicle electrical system comprising multiple onboard power grids, negative terminals of the multiple onboard power grids being respectively connected to a vehicle body ground via different ground points, and the ground offset identification apparatus being configured to identify a ground offset voltage between the ground points, wherein the ground offset identification apparatus comprises: a voltage stabilizing circuit, a ground terminal of the voltage stabilizing circuit being connected to a first ground point between a first onboard power grid of the multiple onboard power grids and the vehicle body ground, so as to provide the voltage stabilizing circuit with a first reference ground voltage GND_LV, wherein the voltage stabilizing circuit is configured to output a constant standard voltage VO on the basis of the first reference ground GND_LV; and a controller, a ground terminal of the controller being connected to a second ground point between a second onboard power grid of the multiple onboard power grids and the vehicle body ground, so as to provide the controller with a second reference ground voltage GND_HV, wherein the controller comprises a sampling port that is connected to an output of the voltage stabilizing circuit, the controller being configured to collect in real time a voltage difference V_OUT of the output voltage of the voltage stabilizing circuit relative to the second reference ground GND_HV, with the aid of the sampling port, and identify whether a ground offset is present in the vehicle electrical system on the basis of the voltage difference V_OUT and the standard voltage VO of the voltage stabilizing circuit.

2. The ground offset identification apparatus as claimed in claim 1 , wherein the controller is further configured to: calculate an offset amount AV between the voltage difference V_OUT and the standard voltage VO of the voltage stabilizing circuit; and judge whether the offset amount AV is greater than a set threshold value, wherein if the offset amount AV is greater than the set threshold value, determine that a ground offset is present in the vehicle electrical system.

3. The ground offset identification apparatus as claimed in claim 1 or 2, wherein the controller is further configured to: send an alarm signal to a whole vehicle controller of the vehicle when it is determined that a ground offset is present in the vehicle electrical system.

4. The ground offset identification apparatus as claimed in claim 1 or 2, wherein a drive circuit is provided in the vehicle electrical system, and the drive circuit is configured to drive at least one load of the vehicle under the control of the controller.

5. The ground offset identification apparatus as claimed in claim 4, wherein the controller is further configured to: control the drive circuit to terminate the operation of the at least one load when it is determined that a ground offset is present in the vehicle electrical system.

6. A vehicle electrical system, wherein the system comprises: multiple onboard power grids, negative terminals of the multiple onboard power grids being respectively connected to a vehicle body ground via different ground points; and the ground offset identification apparatus as claimed in any one of claims 1 to 5.

7. The vehicle electrical system as claimed in claim 6, wherein the vehicle electrical system comprises a mild hybrid system of a vehicle, wherein the mild hybrid system comprises a first onboard power grid and a second onboard power grid that are respectively provided with different power supply sources.

8. The vehicle electrical system as claimed in claim 7, wherein a drive circuit is provided in the second onboard power grid, and the drive circuit is configured to drive at least one load of the vehicle under the control of the controller.

9. The vehicle electrical system as claimed in claim 8, wherein the at least one load comprises a BSG electric machine that is arranged in the mild hybrid system.

10. The vehicle electrical system as claimed in any one of claims 7 to 9, wherein the first onboard power grid comprises a 12 V storage battery, and the second onboard power grid comprises a 48 V power source.

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