Leakage Detection Circuit Using Time-Division Multiplexing
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Solution Overview
Problem
Existing leakage detection circuits for electric vehicle battery packs require two voltage detection circuits, leading to a complex circuit structure and increased costs, making them less efficient and more expensive.
Innovation Solution
A simplified leakage detection circuit using a single voltage detector, a controller, first and second leakage detection switches, a leakage detection resistor, and a calculator, which alternately turns the switches ON and OFF to detect leakage voltage values and calculate the leakage resistance value using a single voltage detector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two voltage detection circuits are used to detect leakage resistance values in battery packs, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent applies periodic action by alternately switching between two leakage detection switches (SW1 and SW2) in different time periods. During the first time period, SW1 is ON and SW2 is OFF to detect voltage from the high-voltage side. During the second time period, SW1 is OFF and SW2 is ON to detect voltage from the low-voltage side. This time-division multiplexing approach allows a single voltage detector to sequentially measure both sides, achieving the same leakage resistance detection capability as two simultaneous detectors while reducing circuit complexity.
Solution Approach 2:
The patent makes the single voltage detector universal by enabling it to perform multiple functions through the switching mechanism. The same voltage detector is used to detect leakage voltage from both the high-voltage side (via SW1) and the low-voltage side (via SW2) at different times. This multi-functionality eliminates the need for separate detection circuits for each side, reducing overall device complexity while maintaining measurement precision.
2Reliability
If two voltage detection circuits are used to detect leakage resistance values, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
By using periodic switching of SW1 and SW2 with a single voltage detector, the patent achieves reliable leakage detection without the cost of two simultaneous detectors. The controller manages the switching timing to ensure accurate measurements from both battery terminals, maintaining detection reliability while reducing component count and manufacturing cost.
Solution Approach 2:
The patent uses a single voltage detector to effectively 'copy' the detection function for both high-voltage and low-voltage sides by switching between them. Instead of purchasing and installing two separate detection circuits, the same detector is reused in different time slots, reducing manufacturing cost while maintaining the reliability needed for safety-critical leakage detection.
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 circuit effectively detects leakage resistance values with a simpler and less expensive structure, enhancing safety and reducing costs for electric vehicles by using a single voltage detector to calculate leakage resistance.
Implementation Method 1
a voltage detector 4 that detects voltage values across the leakage detection resistor 5
Data Source
AI summary
A leakage detection circuit for an electric vehicle includes a battery pack, first and second leakage detection switches, a controller, a leakage detection resistor, a voltage detector, and a calculator. The first and second leakage detection switches are connected to the high and low voltage sides of the battery pack, respectively. The battery pack includes a plurality of batteries that are connected in series. The midpoint of the leakage detection resistor is connected to the ground via the first and second leakage detection switches. The controller alternately turns the first and second leakage detection switches ON. Thus, the voltage detector detects leakage voltage values that are generated in the leakage detection resistor. The controller turns the first and second leakage detection switches ON and OFF, respectively, to detect a first leakage voltage value of the leakage voltage values. On the other hand, the controller turning the first and second leakage detection switches OFF and ON, respectively, to detect a second leakage voltage value of the leakage voltage values. Consequently, the calculator detects leakage based on the first and second leakage voltage values.