Insulation Resistance Measurement Circuit for Electric Vehicles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing measuring devices for electric vehicles require complex circuits and high manufacturing costs to independently determine high and low potential insulation resistances, which are crucial for operational safety and stability, but current solutions only provide a combined leakage resistance value.
Innovation Solution
A measuring device comprising a measuring unit with a first and second tap, a switch, and a measuring resistor, along with a voltage detecting unit and control unit that determines high and low potential insulation resistances using specific mathematical functions and operational amplifier circuits, reducing circuit complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a leakage detection circuit is implemented using four resistors, two switches, and an inverter, then insulation resistance can be detected, but circuit complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts and eliminates unnecessary circuit components from the prior art solution. By removing the inverter and reducing the number of resistors and switches, the circuit achieves insulation resistance detection with minimal components, directly resolving the contradiction between detection capability and circuit complexity
Solution Approach 2:
The patent employs a simple, cost-effective circuit design that replaces expensive and complex components with cheaper, simpler alternatives. The streamlined circuit using only resistors and switches without an inverter reduces manufacturing cost while maintaining detection functionality
2Reliability
If a leakage detection circuit with four resistors and two switches is used, then detection function is achieved, but manufacturing cost increases
Solution Approach 1:
The patent removes the inverter component from the circuit, which significantly reduces manufacturing cost. The simplified circuit achieves the same detection function using fewer components, directly addressing the cost issue while maintaining reliability
Solution Approach 2:
The patent uses a minimal set of basic components (resistors and switches) that are inexpensive and easy to manufacture, replacing complex and expensive components like inverters. This approach lowers manufacturing cost while preserving the essential detection capability
3Reliability
If mathematical operations are performed on combined leakage resistance, then a combined value is obtained, but high potential and low potential insulation resistances cannot be independently determined
Solution Approach 1:
The patent segments the measurement process into two distinct measurement phases. By using different switch configurations in different measurement steps, the circuit independently measures high potential insulation resistance and low potential insulation resistance, resolving the contradiction between combined measurement and independent measurement capability
Solution Approach 2:
The patent employs dynamic switching of circuit configurations to enable different measurement modes. The switches are controlled to create different circuit paths for measuring high potential and low potential insulation resistances separately, allowing independent determination of both values through a single integrated circuit
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 independent measurement of high and low potential insulation resistances with reduced circuit complexity and manufacturing costs, enhancing operational safety and stability of electric vehicle systems by providing distinct resistance values and alerting mechanisms for insufficient insulation.
Implementation Method 1
The voltage detecting unit is for detecting a voltage formed between the first tap and the second tap
Implementation Method 2
The control module is configured to determine the high potential insulation resistance from a product of the resistance value of the measuring resistor and the first function, and to determine the low potential insulation resistance from a product of the resistance value of the measuring resistor and the second function
Data Source
AI summary
A measuring device for measuring insulation resistance of an electric vehicle includes a measuring unit, a voltage detecting unit, and a control unit. The measuring unit includes a first tap, a second tap, a switch, and a measuring resistor. The first tap is to be electrically coupled to a high potential side of a high voltage system. The second tap is to be electrically coupled to a ground side of a low voltage system. The switch and the measuring resistor are connected in series between the first tap and the second tap. The voltage detecting unit is for detecting a voltage formed between the first tap and the second tap. The control unit is operable for controlling ON and OFF states of the switch, and is configured to determine the high potential insulation resistance and the low potential insulation resistance after operating the switch in the ON and OFF states.