Pre-Charge Power Network Circuit With Temperature-Independent Current Limiting
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Solution Overview
Problem
Existing pre-loading devices for electric vehicle power networks are sensitive to ambient temperature variations and require diverse thermistors for different vehicle types, leading to component diversity and increased complexity.
Innovation Solution
A pre-loading device with a main transistor, control module, and power module that limits current intensity independently of temperature, using passive electrical components and pulse width modulation to regulate current, allowing direct energy sourcing from the power line and providing protection against short-circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermistor is used to limit inrush current during pre-charging, then the current is automatically limited during normal operation, but the internal resistance becomes highly dependent on ambient temperature and requires different thermistors for different vehicle types
Solution Approach 1:
The patent replaces the passive thermistor-based current limiting system with an active electronic control system comprising a transistor, control module, and power supply module. This substitution eliminates the temperature-dependent characteristics of thermistors while maintaining automatic current limiting functionality through electronic regulation.
Solution Approach 2:
The control module automatically regulates the main transistor to limit current during pre-charging operations without requiring manual intervention or temperature-based component selection. The system self-adjusts based on operational conditions rather than environmental temperature variations.
2Ease of manufacture
If a thermistor is used for pre-charging, then current limiting is achieved, but component diversity increases and the system becomes more complex for different vehicle types
Solution Approach 1:
The electronic control system with transistor and control module provides a universal solution that can be applied across different vehicle types without requiring different thermistor specifications. The active control circuitry adapts to various operational requirements while maintaining a standardized component architecture.
Solution Approach 2:
The system changes from passive resistance-based current limiting to active electronic parameter control, where the control module dynamically adjusts transistor operation to achieve current limiting. This allows precise control of current parameters without being constrained by the fixed temperature-resistance characteristics of thermistors.
3Reliability
If a pre-charge resistor is used, then current limiting is provided, but the device lacks compactness and electromagnetic interference resistance
Solution Approach 1:
The patent replaces the passive pre-charge resistor with an active transistor-based electronic system that provides superior electromagnetic interference resistance. The solid-state electronic components and controlled operation eliminate the electromagnetic vulnerabilities associated with resistive elements.
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 provides a temperature-independent, compact, reliable, and cost-effective pre-loading system that can be used across various vehicle types, effectively managing current intensity and preventing damage from short-circuits during the pre-loading process.
Implementation Method 1
a main transistor, a control module of the main transistor, which is adapted to limit the intensity of the current flowing in the electrical power supply line
Implementation Method 2
a power supply module of said control module, which is connected to the electrical power supply line, on either side of the main transistor (so as to provide the energy necessary for the operation of the assembly)
Data Source
Figure 1~2
Figure 3A~3C
Figure 4A~4C
AI summary
The invention relates to a device (10) for pre-charging an electric power grid comprising: - an electric power supply line (L1) for supplying power to the electric power grid (10), including a main transistor (Q1); - a control module (12) for controlling the main transistor, which is designed to limit the strength of the current flowing in the electric power supply line; and - a power supply module (14) for supplying power to said control module, which is connected to the electric power supply line, on either side of the main transistor.