Electrochromic Transition Control Using Adaptive Voltage Feedback
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Solution Overview
Problem
Existing electrochromic devices face challenges in uniformly transitioning between optical states due to variations in effective voltage across the device, particularly in larger sizes, leading to non-uniform transitions and inefficiencies in controlling the drive voltage duration.
Innovation Solution
A method for controlling optical transitions in electrochromic devices by applying a drive voltage, measuring open circuit voltage (Voc) and charge delivery, and adjusting the voltage magnitude based on real-time monitoring and feedback to ensure uniform transitions across the device surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a constant drive voltage is applied to electrochromic devices, then the control system is simple, but the optical transition becomes non-uniform across the device surface
Solution Approach 1:
The patent applies different voltage magnitudes to different regions of the electrochromic device by introducing effective voltage correction factors. The drive voltage is modified based on the distance from bus bars, with regions farther from bus bars receiving higher voltage compensation to achieve uniform optical transition across the entire device surface.
Solution Approach 2:
The patent transforms the static constant voltage approach into a dynamic adaptive voltage control system. The drive voltage magnitude is dynamically adjusted based on real-time measurements of optical transition progress and calculated effective voltage distribution, allowing the system to compensate for non-uniformity as the transition progresses.
2Speed
If the drive voltage magnitude is increased to speed up optical transition, then the transition speed increases, but energy consumption and device stress increase
Solution Approach 1:
The patent employs periodic pulsing of the drive voltage rather than continuous application. The controller applies voltage pulses at optimized intervals, allowing the electrochromic material to transition during pulse periods and relax during inter-pulse periods, thereby achieving fast transitions while reducing average energy consumption and device stress.
Solution Approach 2:
The patent dynamically changes voltage parameters (magnitude, duration, pulsing frequency) based on the current state of optical transition. The drive voltage magnitude is adjusted according to the measured open circuit voltage and transition progress, applying higher voltages when needed to accelerate transition and lower voltages when the transition is nearing completion, optimizing both speed and energy efficiency.
3Manufacturing precision
If real-time monitoring and feedback control is implemented to achieve uniform transitions, then optical transition uniformity improves, but device complexity and control algorithm complexity increase
Solution Approach 1:
The patent implements feedback control by continuously monitoring the open circuit voltage during optical transitions and using this information to adjust subsequent drive voltage applications. The measured open circuit voltage serves as a feedback signal that indicates the current state of transition, allowing the controller to adapt the drive voltage to maintain uniformity across the device surface.
Solution Approach 2:
The patent introduces an intermediary effective voltage correction model that simplifies the control algorithm. Instead of directly controlling complex spatial voltage distributions, the system uses a mathematical model to calculate effective voltage correction factors based on simple geometric parameters (distance from bus bars), transforming a complex control problem into a manageable calculation.
4Speed
If higher drive voltage is applied to larger devices to maintain transition speed, then transition speed is maintained, but voltage non-uniformity and device stress increase
Solution Approach 1:
The patent applies local quality control by tailoring the drive voltage magnitude to the specific needs of different device sizes and geometries. The effective voltage correction factors are calculated based on the distance from bus bars, which automatically scales with device size, ensuring that larger devices receive appropriate voltage compensation without excessive overall voltage that would cause stress.
Solution Approach 2:
The patent uses dynamic voltage adjustment during the transition process, starting with higher voltages to initiate fast transition in larger devices and then reducing voltage as the transition progresses. This dynamic approach maintains transition speed while avoiding sustained high voltage that would cause device stress and reliability issues.
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 method ensures efficient and uniform optical transitions by dynamically adjusting the drive voltage, addressing non-uniformity issues and optimizing transition times regardless of device size or environmental conditions.
Implementation Method 1
Electrochromic (EC) devices are typically multilayer stacks including (a) at least one layer of electrochromic material, that changes its optical properties in response to the application of an electrical potential
Data Source
AI summary
Methods, systems, apparatuses, and media for controlling optical transitions are provided. In some embodiments, a method comprises: (a) applying a drive voltage having a preset magnitude to an optically switchable device to cause the optically switchable device to transition from an initial optical state toward a target optical state; (b) measuring an open circuit voltage (Voc) of the optically switchable device and/or an amount of charge that has been delivered to the optically switchable device; (c) comparing characteristics of the measured Voc and/or the amount of charge to at least one parameter indicative of a target duration of time for the optically switchable device to transition from the initial optical state to the target optical state; (d) modifying the drive voltage to have a modified magnitude, wherein the modified magnitude is determined based at least in part on the comparison; and (e) repeating (a) and (b) until the target optical state is reached.