Range Extender Bypass Circuit for Voltage Drop Protection
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Solution Overview
Problem
Conventional range extenders for electric vehicles face issues with sudden voltage drops during increased electrical load, leading to rapid current increases that can exceed switch device limits, potentially causing damage and safety hazards due to over-current protection triggering.
Innovation Solution
Incorporating a DC-to-DC converter and a bypass device controlled by a controller to switch between normal and safety modes, where the bypass device takes over when output voltage falls below a critical level, preventing damage by redirecting current through the bypass device and maintaining stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If over-current protection device is triggered to turn off main switch when current exceeds preset value, then switch device is protected from damage, but electrical load operation is interrupted affecting driving safety
Solution Approach 1:
The patent introduces a bypass circuit as an intermediary path that activates when the main switch needs protection. This bypass circuit allows current to flow alternatively, protecting the main switch from over-current damage while maintaining continuous power supply to the electrical load, thus resolving the contradiction between protection and operational continuity
Solution Approach 2:
The system dynamically switches between normal operation mode (main switch conducting) and protection mode (bypass circuit conducting) based on real-time current conditions. This dynamic switching mechanism ensures the main switch is protected when needed while maintaining load operation, resolving the contradiction between reliability and productivity
2Reliability
If proportional-integral controller turns on switch devices to pull up output voltage when voltage drops suddenly, then output voltage is stabilized, but current through inductor and switch devices increases rapidly exceeding maximum current
Solution Approach 1:
The bypass circuit is pre-configured and ready to activate before over-current damage occurs. When voltage drops and the controller attempts to compensate by turning on switch devices, the bypass circuit provides an alternative path that prevents excessive current from flowing through the inductor and switch devices, thus preventing the harmful effect before it can cause damage
Solution Approach 2:
The bypass circuit acts as an intermediary that decouples the relationship between voltage stabilization actions and current flow through sensitive components. It allows the controller to stabilize output voltage without directly causing over-current through the inductor and switch devices, resolving the contradiction between voltage stability and over-current prevention
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
Ensures continuous and stable operation of the electrical load during sudden increases in load, preventing switch device overload and ensuring user safety by maintaining voltage stability through the bypass mechanism.
Implementation Method 1
converting an input voltage at the input side into an output voltage at the output side by the DC-to-DC converter, wherein the output voltage is higher than a critical voltage
Data Source
AI summary
A circuit protection method comprises operating a range extender in a normal mode, wherein the range extender comprises at least one DC-to-DC converter having an input side and an output side and at least one bypass device coupled between the input side and the output side. The operating of the range extender in the normal mode comprises converting an input voltage at the input side into an output voltage at the output side by the DC-to-DC converter, wherein the output voltage is higher than a critical voltage. The method further comprises operating the range extender in a safety mode when the output voltage is lower than the critical voltage. The operating of the range extender in the safety mode comprises bypassing the DC-to-DC converter by the bypass device, wherein the critical voltage is lower than or equal to the input voltage.