Insulation State Detection Using Equilibrium Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing insulation state detecting devices for high voltage DC power supplies face reduced detection precision due to the influence of Y capacitors, especially when large capacitances are involved, leading to longer measurement times and non-real-time detection.
Innovation Solution
The introduction of an equilibrium state forming circuit that uses control resistors and switches to rapidly transition the charge states of Y capacitors from non-equilibrium to equilibrium, allowing for precise insulation state measurement even with large capacitance Y capacitors connected to high voltage power supplies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If Y capacitors with large capacitance are connected to the high voltage power supply to filter noise and stabilize operation, then power supply stability is improved, but the detection precision of insulation state is reduced and measurement time increases
Solution Approach 1:
The equilibrium state forming circuit performs preliminary action by actively resetting the charge states of Y capacitors to equilibrium before each insulation state measurement. This preliminary reset eliminates the influence of residual charges that would otherwise distort measurements, enabling high-precision detection even when large-capacitance Y capacitors are present for power supply stability.
Solution Approach 2:
The equilibrium state forming circuit acts as an intermediary between the Y capacitors and the insulation state detecting device. It mediates the interaction by controlling the charge states of Y capacitors through switching elements, ensuring they remain in equilibrium during measurement and thus eliminating their harmful influence on detection precision while allowing them to continue providing power supply stability.
2Stability of the object's composition
If Y capacitors with large capacitance are used for power supply filtering, then power supply stability is improved, but measurement time increases making real-time detection difficult
Solution Approach 1:
The equilibrium state forming circuit performs preliminary action by actively resetting the charge states of Y capacitors to equilibrium before each insulation state measurement. This preliminary reset eliminates the need for long waiting periods for natural equilibrium, enabling rapid real-time measurements even with large-capacitance Y capacitors present for power supply stability.
Solution Approach 2:
The switching elements in the equilibrium state forming circuit perform periodic action by repeatedly and rapidly switching to reset Y capacitor charge states before each measurement cycle. This periodic resetting enables continuous real-time insulation state detection without the measurement time being extended by the capacitance values of Y capacitors, while they continue to provide power supply stability.
3Device complexity
If the charge states of Y capacitors are not reset to equilibrium before measurement, then device complexity is reduced, but detection accuracy deteriorates due to influence of residual charges
Solution Approach 1:
The equilibrium state forming circuit acts as an intermediary that adds minimal complexity only where needed - specifically to control the charge states of Y capacitors. This localized addition of switching elements and control logic maintains overall device simplicity while dramatically improving detection accuracy by eliminating residual charge influences during measurement.
Solution Approach 2:
The equilibrium state forming circuit changes the charge state parameter of Y capacitors from arbitrary values to a standardized equilibrium state before measurement. This parameter standardization enables accurate insulation state detection without requiring complex compensation algorithms, thus improving accuracy while maintaining relatively simple device architecture.
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 high-precision insulation state measurement in a short time, independent of the capacitance values of Y capacitors, by ensuring the charge states of Y capacitors return to equilibrium quickly, thus maintaining detection accuracy across a wide range of resistance values.
Implementation Method 1
a detecting capacitor (referred to as the flying capacitor) is connected between the positive and negative power lines for the high voltage and a ground electrode (the vehicle body) only for a predetermined time. The charge voltage of the flying capacitor is monitored
Implementation Method 2
capacitors called Y capacitors (line bypass capacitors) are often connected between the positive and negative power lines for the high voltage and the ground electrode (in JP-A-2011-21990)
Implementation Method 3
an equilibrium state forming circuit that promotes an operation of transiting a charge state of a positive side electrostatic capacitance between the positive side power line and the ground electrode and a charge state of a negative side electrostatic capacitance between the negative side power line and the ground electrode from non-equilibrium states to equilibrium states
Data Source
AI summary
An insulation state detecting device includes a positive side input terminal connected to a positive side power line of a high voltage DC power supply, a negative side input terminal connected to a negative side power line of the high voltage DC power supply, a ground electrode, a controller that detects insulation states between the positive side power line and the negative side power line and the ground electrode based on a charge voltage of a flying capacitor, and an equilibrium state forming circuit that promotes an operation of transiting a charge state of a positive side electrostatic capacitance between the positive side power line and the ground electrode and a charge state of a negative side electrostatic capacitance between the negative side power line and the ground electrode from non-equilibrium states to equilibrium states.