Vehicle Electrical Ground Segmentation for Control Unit Protection
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Solution Overview
Problem
In hybrid traction vehicles, electrical faults can cause the melting of small-section electrical cables connecting the low voltage storage system to microprocessor control units, leading to a loss of power and malfunction of control units.
Innovation Solution
Incorporating an interconnection resistor with high impedance between the electrical grounds of the DC/DC power converter and microprocessor control units, or galvanic insulation between these grounds, to prevent excessive current flow through small-section cables and maintain electrical connection, thereby preventing cable damage and ensuring continuous operation of control units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If two different electrical cables (large section for high current and small section for low current) are used to connect the low voltage storage system to the DC/DC power converter and microprocessor control units, then the electrical supply requirements are met, but the small-section cable is vulnerable to melting during electrical faults
Solution Approach 1:
The patent introduces an intermediary protective device (fuse or circuit breaker) in series with the small-section cable connecting the low voltage storage system to the microprocessor control units. This intermediary component detects excessive current conditions and interrupts the circuit before the cable can overheat and melt, thereby protecting the cable while maintaining normal electrical supply functionality
Solution Approach 2:
The patent implements protective measures (fuse or circuit breaker) in advance before electrical faults can occur. These protective devices are pre-installed in the electrical circuit to cushion against potential harmful effects of electrical faults, preventing cable damage before it happens
2Ease of operation
If the electronic microprocessor control units are supplied by the low voltage storage system, then the control units can operate, but electrical faults can cause cable melting and loss of power to these control units
Solution Approach 1:
The patent places an intermediary protective device (fuse or circuit breaker) between the low voltage storage system and the microprocessor control units. This intermediary protects the control units by interrupting excessive current flow during electrical faults, preventing cable melting and ensuring continuous operation of the control units under normal conditions
3Device complexity
If the DC/DC power converter and microprocessor control units share a common electrical ground, then the electrical system is simplified, but electromagnetic interference can affect control unit operation
Solution Approach 1:
The patent segments the electrical ground into separate grounds: one for the DC/DC power converter and another for the microprocessor control units. This segmentation isolates the sensitive control units from electromagnetic interference generated by the power converter, while maintaining system functionality. The separate grounds prevent interference coupling while preserving electrical system operation
Solution Approach 2:
The patent applies different ground configurations to different parts of the system: the DC/DC power converter operates with its own ground reference, while the microprocessor control units have a dedicated clean ground. This local quality differentiation ensures that each component operates in its optimal electrical environment, with sensitive control units protected from interference
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution ensures the robustness and cost-effectiveness of the electrical system by preventing cable melting and maintaining functionality of microprocessor control units during cable interruptions, while also shielding against electromagnetic interference.
Implementation Method 1
an interconnection resistor with high impedance connecting the electrical ground of the electronic DC/DC power converter to the electrical ground of the electronic microprocessor control unit
Implementation Method 2
galvanic insulation between the electrical ground of the electronic DC/DC power converter and the electrical ground of the electronic microprocessor control unit
Data Source
Figure 1
Figure 2
AI summary
An electrical system (11) of a vehicle (1) with electrical traction provided with a reversible electric machine (8) that can be mechanically connected to drive wheels (3); the electrical system (11) has: a low voltage storage system (14); an electronic power converter (15) having a positive pole (21) and a negative pole or electrical ground (23) that are connected to the low voltage storage system (14) through a first electrical cable (18) having a large section; and an electronic control unit (17) that controls the electronic power converter (15) and has a positive pole (24) and a negative pole or electrical ground (25) that are connected to the low voltage storage system (14) through a second electrical cable (19) having a small section; wherein the electrical ground (23) of the electronic power converter (15) is connected to the electrical ground (25) of the electronic control unit (17) only through an impedance having value not lower than 100 Ohm.