High-Voltage System Grounding Cable Leakage Current Control
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Solution Overview
Problem
The insulation resistance between the outer cylinder of a vibration damping mechanism and the vehicle chassis decreases when exposed to muddy or saltwater, leading to increased leakage current and noise, which affects surrounding electronic devices.
Innovation Solution
A high-voltage system with a transformer-based circuit configuration that includes resistors with different resistance values between connection points and ground, ensuring direct grounding of the outer cylinder and increasing impedance for leakage current paths, thereby reducing noise and protecting against electric shock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulator such as a rubber bush or rubber mount is used to connect the outer cylinder to the vehicle chassis, then electrical insulation is provided, but the insulation resistance decreases when exposed to muddy water or salt water, leading to increased leakage current
Solution Approach 1:
The patent introduces a grounding cable as an intermediary component to directly connect the outer cylinder to the vehicle chassis ground. This grounding cable serves as a dedicated low-impedance path for leakage current, separating the grounding function from the insulator and preventing the insulator from needing to provide both insulation and grounding paths simultaneously.
Solution Approach 2:
The patent segments the electrical connection system into distinct functional components: the insulator maintains electrical isolation between the high-voltage circuit and chassis, while the grounding cable provides a separate dedicated path for leakage current. This segmentation allows each component to optimize its specific function without compromising the other.
2Ease of operation
If the insulation resistance decreases due to exposure to muddy water or salt water, then leakage current increases and returns to the control device via chassis ground, but this causes noise to increase and adversely affects surrounding electronic devices
Solution Approach 1:
The grounding cable acts as an intermediary that intercepts leakage current before it can return to the control device through the chassis ground path. By providing a direct low-impedance connection from the outer cylinder to ground, it guides the leakage current through a controlled path that does not pass through sensitive electronic circuits, thereby preventing noise generation.
3Reliability
If the outer cylinder is directly grounded to the chassis ground using a grounding cable, then the impedance of the leakage current path is increased and leakage current is reduced, but additional components are required
Solution Approach 1:
The grounding cable serves multiple functions simultaneously: it provides a low-impedance path for leakage current, protects against electric shock by ensuring the outer cylinder is at ground potential, and reduces noise by preventing leakage current from passing through electronic circuits. This multi-functionality justifies the addition of the component by delivering multiple benefits from a single addition.
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
The solution effectively prevents electric shock and reduces noise by ensuring the outer cylinder is directly grounded and increasing the impedance of leakage current paths, thus safeguarding electronic devices from adverse effects.
Implementation Method 1
a second circuit that is magnetically coupled to the first circuit via a transformer
Implementation Method 2
The electrorheological fluid is a fluid whose viscosity can be controlled by applying an electric field having a high electric field intensity of about several kV/mm from outside
Data Source
AI summary
Provided are a reliable high-voltage system and a failure diagnosis method thereof, in which a vibration damping mechanism using an electrorheological fluid as a working fluid is a load, and can prevent electric shock due to leakage current and the influence on surrounding electronic devices. There are provided a first circuit that includes a power source and a ground, a second circuit that is magnetically coupled to the first circuit via a transformer and includes a load connected to the ground, a controller that is connected to the ground, a third circuit that is connected to the second circuit and the ground, a first resistor that is provided between a connection point at a high potential end of the second circuit and the ground, and a second resistor that is provided between a connection point at a low potential end of the second circuit and the ground, and has a resistance value different from a resistance value of the first resistor.