Deterioration Detection for Vehicle Power Sources Using Segmented Charging Paths
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Solution Overview
Problem
Existing deterioration detection methods for electric power sources in vehicles, such as hybrid electric vehicles, face challenges in accurately distinguishing between deteriorations in insulation resistors and capacitors due to voltage changes, leading to potential misdiagnosis and inaccurate monitoring of the insulated state.
Innovation Solution
A deterioration detecting apparatus and method that includes a capacitor connected to an electric power source through a connection switch, a deterioration detection switch between the power source and ground, and a charging-path forming unit to control the connection and detect voltage changes, allowing for precise identification of deteriorations in elements on the charging path, including capacitors and resistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flying capacitor system is used to detect insulation resistor deterioration by measuring capacitor voltage, then insulation monitoring is enabled, but capacitor deterioration cannot be distinguished from insulation resistor deterioration
Solution Approach 1:
The detection function is segmented into two separate detection paths: one for detecting insulation resistor deterioration (through the insulating resistor R1) and another for detecting capacitor deterioration (through the capacitor C1). This segmentation allows independent detection of each component's status, resolving the inability to distinguish between different types of deterioration in the original single-path system.
Solution Approach 2:
A deterioration detection switch S7 is introduced as an intermediary component that enables selective connection to different detection paths. By controlling the switch state, the system can route voltage measurements through either the insulating resistor path or the capacitor path, allowing independent assessment of each component without interfering with normal operation.
2Ease of operation
If capacitor voltage is used as the sole detection parameter, then detection simplicity is maintained, but false detection occurs when capacitor electrostatic capacity changes
Solution Approach 1:
The detection approach transitions from using only voltage magnitude to using voltage change rate (dV/dt) as the detection parameter. By monitoring how the voltage changes over time during charging and discharging phases, the system can identify capacitor deterioration through abnormal voltage change patterns while maintaining simple voltage-based measurement methodology.
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
Enables accurate detection of deteriorations in elements on the charging path, preventing misdiagnosis and ensuring reliable monitoring of the electric power source's insulated state, thereby improving the reliability of vehicle systems.
Implementation Method 1
a capacitor C1 that is connected to an electric power source through a connection switch S1 to S6
Implementation Method 2
a voltage detecting unit that detects a voltage of the capacitor charged through the charging path
Data Source
AI summary
A deterioration detecting apparatus includes: a capacitor that is connected to an electric power source through a connection switch; a deterioration detection switch that is provided between the electric power source and a ground point; a charging-path forming unit that controls the connection switch and the deterioration detection switch, such that the electric power source, the capacitor, and the ground point are connected, to form a charging path for charging the capacitor; a voltage detecting unit that detects a voltage of the capacitor charged through the charging path; and a deterioration detecting unit that detects a deterioration in elements such as the capacitor positioned on the charging path, on the basis of the voltage of the capacitor detected by the voltage detecting unit.