PWM to DC Power Conversion for Electrochromic Mirrors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle systems face challenges in providing direct current (DC) power to electrochromic mirrors due to the need for multiple discrete wires and lack of provisions in existing control modules and wire harnesses, especially when retrofitting outside mirrors with electrochromic glass, which complicates independent control and power supply.
Innovation Solution
A system that converts pulse width modulated (PWM) power sources to DC power using hold-up circuits and microcontrollers, allowing for efficient power supply to electrochromic mirrors by controlling the drive circuit based on PWM pulse widths, reducing the need for separate wiring and addressing power dissipation issues associated with PWM square wave signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If PWM power source is used to supply power to electrochromic mirrors, then power supply efficiency is improved, but power dissipation issues arise due to PWM square wave signals
Solution Approach 1:
The patent converts the PWM square wave signal parameters into a sinusoidal waveform through a waveform generator circuit. This parameter transformation changes the signal characteristics from a square wave with high dv/dt (causing power dissipation) to a sinusoidal wave with smoother transitions, thereby reducing power dissipation while maintaining PWM-driven efficiency
Solution Approach 2:
The patent introduces an intermediary circuit (waveform generator and filter) between the PWM power source and the electrochromic mirror. This intermediary transforms the PWM square wave into a conditioned sinusoidal waveform, mediating the power transmission to eliminate harmful power dissipation effects while preserving the efficiency benefits of PWM control
2Ease of operation
If multiple discrete wires are used for power supply, then independent control is achieved, but wiring complexity increases
Solution Approach 1:
The patent combines multiple discrete control functions into a single integrated control module that receives PWM input and generates all necessary control signals for the electrochromic mirror. This merging eliminates the need for multiple separate wires and control circuits, reducing wiring complexity while maintaining independent control capability through the integrated module's internal signal generation
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 efficient and controlled DC power supply to electrochromic mirrors, reducing the complexity of wiring and power dissipation, while effectively managing reflectance and bleaching operations across varying light and temperature conditions.
Implementation Method 1
A first hold-up circuit converts the PWM power source to a DC power supplied to at least one microcontroller and a second hold-up circuit for converts the PWM power source to DC power source supplied to an electrochromic (EC) mirror drive circuit
Data Source
AI summary
A power supply for supplying direct current (DC) power from a pulse width modulated (PWM) source includes a connector configured to be in electrical communication with a PWM power source. A hold-up circuit is in electrical communication with the connector and is configured to convert electrical power supplied from the PWM power source to DC power. This DC power is supplied to a drive circuit where a microcontroller is configured to control the drive circuit by supplying the DC power from the drive circuit to a load.