Electrochromic Window PWM Control for Precise DC Voltage
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Solution Overview
Problem
Existing technologies for controlling optically-switchable devices, such as electrochromic windows, face challenges in efficiently organizing, controlling, and delivering power, particularly in integrating them into new and existing applications, including buildings, to optimize energy efficiency and aesthetic purposes.
Innovation Solution
A window controller system that includes a command-voltage generator and a pulse-width-modulated-signal generator to drive optically-switchable devices on transparent substrates, with a network controller managing multiple window controllers to integrate with building management systems and other systems for holistic energy control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If electrochromic windows are integrated into buildings to control light transmission and optimize energy efficiency, then energy conservation is improved, but the complexity of organizing, controlling, and delivering power increases
Solution Approach 1:
The patent divides the power delivery system into multiple independent power components (first power component and second power component), each capable of delivering power pulses to different electrode layers. This segmentation allows independent control of each power component, simplifying the overall control architecture while maintaining the ability to manage complex electrochromic window operations.
Solution Approach 2:
The system dynamically adjusts the duty cycles of the first and second power components based on operational requirements. By varying the duty cycles, the controller can adapt the effective DC voltage applied to the electrochromic device in real-time, enabling flexible control of light transmission while optimizing energy consumption patterns.
2Measurement precision
If pulse-width modulation is used to control the effective DC voltage applied to electrochromic devices, then control precision is improved, but the device complexity increases
Solution Approach 1:
The patent employs periodic pulse-width modulation where the first and second power components deliver repeated pulses at specific duty cycles. This periodic action enables precise control of the effective DC voltage by adjusting the proportion of time each power component is active, achieving accurate voltage control through temporal modulation rather than complex circuitry.
Solution Approach 2:
The system controls the effective DC voltage by changing the duty cycle parameters of the pulse-width modulated signals. By adjusting the duty cycles of the first and second power components, the controller can precisely regulate the average voltage applied to the electrochromic device without requiring complex voltage regulation circuits.
3Adaptability or versatility
If multiple power components with different duty cycles are used to drive electrochromic devices, then adaptability is improved, but the difficulty of detecting and measuring increases
Solution Approach 1:
The controller is designed to universally manage multiple power components with different duty cycles through a unified control architecture. This multi-functional controller can adapt to various operational modes and electrochromic device configurations, providing versatile power delivery while maintaining consistent measurement and control methods across different operating conditions.
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 system effectively controls and drives electrochromic windows to optimize energy efficiency and aesthetic purposes by adjusting light transmission based on feedback and input from various building systems, enhancing energy conservation and reducing operational costs.
Implementation Method 1
A pulse-width-modulated-signal generator is configured to generate a pulse-width-modulated signal based on the command voltage signal. The pulse-width-modulated signal includes a first power component having a first duty cycle and a second power component having a second duty cycle.
Implementation Method 2
Electrochromism is a phenomenon in which a material exhibits a reversible electrochemically-mediated change in one or more optical properties when stimulated to a different electronic state. For example, the electrochromic material can be stimulated by an applied voltage.
Implementation Method 3
Tungsten oxide is a cathodic electrochromic material that undergoes a coloration transition—transparent to blue—by electrochemical action via intercalation of positive ions into the tungsten oxide matrix with concurrent charge balance by electron insertion.
Data Source
AI summary
This disclosure provides a window controller that includes a command-voltage generator that generates a command voltage signal, and a pulse-width-modulated-signal generator that generates a pulse-width-modulated signal based on the command voltage signal. The pulse-width-modulated signal drives an optically-switchable device. The pulse-width-modulated signal comprises a first power component having a first duty cycle and a second power component having a second duty cycle. The first component delivers a first pulse during each active portion of the first duty cycle, and the second component delivers a second pulse during each active portion of the second duty cycle. The first pulses are applied to a first conductive layer and the second pulses are applied to a second conductive layer. The relative durations of the active portions and the relative durations of the first and second pulses are adjusted to result in a change in an effective DC voltage applied across the optically-switchable device.