Vehicle Pre-Charge Control Delay for Jump-Start Overvoltage
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Solution Overview
Problem
In vehicle control systems, the pre-charge circuit is vulnerable to overvoltage conditions during jump-start scenarios, leading to potential damage when the power supply voltage exceeds the operating range, causing the control circuit to incorrectly initiate the initial check and apply excessive voltage to the pre-charge circuit.
Innovation Solution
Implementing a vehicle control apparatus with a preset period delay after the power supply voltage enters the operating range, preventing immediate activation of the pre-charge circuit when the power switch is turned off under overvoltage conditions, thus avoiding overvoltage application to the pre-charge circuit by ensuring the voltage decreases below the operating range before charging begins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the control circuit immediately initiates initial check when power supply voltage enters the operating range, then the system responds quickly to power-on conditions, but the pre-charge circuit may be damaged by overvoltage during jump-start scenarios
Solution Approach 1:
The control circuit introduces a predetermined period delay before initiating the initial check after power supply voltage enters the operating range. This preliminary waiting period allows the power supply voltage to stabilize and prevents the pre-charge circuit from being exposed to overvoltage conditions during jump-start scenarios, thereby protecting the circuit while maintaining timely operation.
2Speed
If the power supply relay is activated immediately after capacitor charging, then the system starts operating quickly, but inrush current may damage the circuit components
Solution Approach 1:
The control circuit performs preliminary charging of the capacitor through the pre-charge circuit before activating the power supply relay. This preliminary charging action reduces the voltage difference between the capacitor and power supply, thereby minimizing inrush current when the relay closes while still enabling quick system startup.
Solution Approach 2:
The pre-charge circuit acts as an intermediary between the power supply and the main circuit. It provides a controlled charging path for the capacitor, limiting current flow during the charging phase and preventing direct connection that would cause inrush current, while still enabling efficient power transfer after charging is complete.
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
This solution effectively protects the pre-charge circuit from overvoltage, reducing the risk of anomalies and extending the lifespan of components, while maintaining efficient operation by avoiding false initial checks and ensuring the pre-charge circuit is not subjected to voltages beyond its durable limits.
Implementation Method 1
a capacitor for power supply stabilization, the capacitor being connected in parallel with the drive circuit
Implementation Method 2
The control circuit starts charging the capacitor by turning on the pre-charge circuit
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A vehicle control apparatus capable of protecting a pre-charge circuit is provided. When a voltage (Vig) (IG voltage) has entered an operating voltage range (δV) (step S101), a microcomputer determines whether a preset period (T2) has elapsed from then (step S102). Upon determining that the preset period (T2) has elapsed (step S102: YES), the microcomputer starts initial check (step S103). To carry out the initial check, the microcomputer starts charging a capacitor for power supply stabilization of a drive circuit by turning on the pre-charge circuit (52) and, when the charging of the capacitor is completed, turns on a power supply relay (53) provided on a power supply line that connects between a battery and the drive circuit.