Insulation Detection Circuit Using Constant Current Charging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The progression of vehicles towards hybrid and electric systems poses a safety risk due to potential insulation damage between high voltage and low voltage power, leading to harmful electric shocks if the insulation between these powers is compromised, necessitating improved insulation detection accuracy to prevent accidents.
Innovation Solution
An insulation detection circuit utilizing a constant current unit to charge/discharge a second energy storage unit, with a detection unit monitoring current changes; when the current falls below a predetermined value, it outputs a signal indicating abnormal insulation status, enhancing detection precision and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional insulation detection circuit is used, then the basic detection function is provided, but the detection precision is insufficient and cannot reliably detect insulation damage under vehicle operation conditions
Solution Approach 1:
The patent applies preliminary action by charging the second capacitor before insulation detection occurs. The constant current unit charges the second capacitor in advance, storing energy that will be used for subsequent detection. This preliminary charging action ensures that the detection circuit is ready and that the capacitor has sufficient charge to provide accurate detection signals when insulation damage occurs, thereby improving detection precision and reliability.
Solution Approach 2:
The patent implements feedback by continuously monitoring the voltage across the second capacitor and comparing it against reference values. The detection unit receives feedback signals from the voltage measurement and uses this information to determine whether insulation damage has occurred. This feedback mechanism allows the system to reliably detect insulation defects by comparing actual voltage levels against expected values, significantly improving detection accuracy.
2Reliability
If the detection circuit operates continuously to monitor insulation status, then real-time safety monitoring is achieved, but energy consumption increases
Solution Approach 1:
The patent applies periodic action by using the second capacitor to store energy during charging periods and then utilizing this stored energy for detection during discharging periods. The constant current unit operates periodically to charge the capacitor, and the detection unit periodically monitors the voltage. This periodic operation pattern allows the system to maintain reliable safety monitoring while reducing overall energy consumption compared to continuous operation, as the capacitor retards the discharge of stored charge during detection phases.
3Device complexity
If a simple detection circuit is used, then device complexity is reduced, but detection accuracy deteriorates
Solution Approach 1:
The patent applies segmentation by dividing the detection circuit into distinct functional modules: a constant current unit for charging, a second capacitor for energy storage, and a detection unit for monitoring. This segmentation allows each component to perform its specific function efficiently while maintaining overall system simplicity. The modular structure makes the circuit easier to design, implement, and maintain, while achieving high detection accuracy through the coordinated operation of these segmented functions.
Solution Approach 2:
The patent uses the second capacitor as an intermediary element between the constant current unit and the detection unit. This intermediary component stores energy and provides a stable voltage source for detection, isolating the detection circuit from direct connection to the high-voltage insulation being monitored. The intermediary capacitor simplifies the overall circuit architecture by providing a buffer that stabilizes voltage and enhances detection accuracy without requiring complex direct monitoring arrangements.
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 detects insulation damage between high voltage and low voltage power, ensuring user safety by providing a precise and convenient insulation detection method, reducing the risk of electric shocks and enhancing the reliability of insulation detection circuits.
Implementation Method 1
a second energy storage unit coupled between the first energy storage unit and the low voltage power
Implementation Method 2
The detection unit is coupled to the second energy storage unit for detecting a current change of the second energy storage unit
Data Source
AI summary
An insulation detection circuit suitable for detecting an insulation status between a high voltage power and a low voltage power of a vehicle is disclosed. The circuit includes a first energy storage unit, a second energy storage unit, a constant current unit, and a detection unit. The first energy storage unit is coupled to the high voltage power. The second energy storage unit is coupled between the first energy storage unit and the low voltage power. The constant current unit is coupled between the first energy storage unit and the second energy storage unit. The detection unit is coupled to the second energy storage unit for detecting a current change of the second energy storage unit. When the detection unit detects that current flowing through the second energy storage unit is smaller than a predetermined value, a detection signal representing that the insulation status is abnormal is outputted.