Controller for optically-switchable windows

Abstract

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.

What is claimed is: 
     
         1 . A window controller comprising:
 a command-voltage generator configured to generate a command voltage signal;   a pulse-width-modulated-signal generator configured to generate a pulse-width-modulated signal based on the command voltage signal, the pulse-width-modulated signal configured to drive an optically-switchable device on a substantially transparent substrate, wherein:
 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 power component is configured to deliver a first pulse during each active portion of the first duty cycle; 
 the second power component is configured to deliver a second pulse during each active portion of the second duty cycle; and 
 during operation, the first pulses are applied to a first conductive electrode layer of the optically-switchable device and the second pulses are applied to a second conductive electrode layer of the optically-switchable device; wherein the relative durations of the active portions of the first and second duty cycles 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. 
   
     
     
         2 . The window controller of  claim 1 , wherein the substantially transparent substrate is configured in an IGU. 
     
     
         3 . The window controller of  claim 2 , wherein the window controller is located at least partially within a seal of the IGU. 
     
     
         4 . The window controller of  claim 2 , wherein the optically-switchable device is an electrochromic device formed on a surface of the substantially transparent substrate and adjacent an interior volume of the IGU. 
     
     
         5 . The window controller of  claim 4 , wherein the electrochromic device is entirely comprised of inorganic solid-state materials. 
     
     
         6 . The window controller of  claim 1 , wherein:
 the first duty cycle has a first time period and a first voltage magnitude;   the second duty cycle has a second time period and a second voltage magnitude;   the first time period equals the second time period; and   the first voltage magnitude equals the second voltage magnitude.   
     
     
         7 . The window controller of  claim 6 , further comprising first and second inductors that couple the first and second power components to the optically-switchable device, wherein the voltage applied across the optically-switchable device resulting from the applied first and second power components is effectively a DC voltage. 
     
     
         8 . The window controller of  claim 7 , wherein:
 the active portion of the first duty cycle comprises a first fraction of the first time period; and   the active portion of the second duty cycle comprises a second fraction of the second time period.   
     
     
         9 . The window controller of  claim 8 , wherein:
 the magnitude of the voltage applied to a first conductive layer of the optically-switchable device is substantially proportional to the product of the first fraction and the first voltage magnitude;   the magnitude of the voltage applied to a second conductive layer of the optically-switchable device is substantially proportional to the product of the second fraction and the second voltage magnitude; and   the effective DC voltage applied across the optically-switchable device is substantially equal to the difference between the magnitude of the voltage applied to the first conductive layer and the magnitude of the voltage applied to the second conductive layer.   
     
     
         10 . The window controller of  claim 1 , wherein the command-voltage generator includes a microcontroller configured to generate the command voltage signal. 
     
     
         11 . The window controller of  claim 10 , wherein the microcontroller generates the command voltage signal based at least in part on a voltage feedback signal that is itself based on an effective DC voltage applied across the optically-switchable device. 
     
     
         12 . The window controller of  claim 10 , wherein the microcontroller generates the command voltage signal based at least in part on a current feedback signal that is itself based on a detected current transmitted through the optically-switchable device. 
     
     
         13 . The window controller of  claim 10 , further comprising a memory device configured to store one or more drive parameters. 
     
     
         14 . The window controller of  claim 13 , wherein the drive parameters include one or more of a current outside temperature, a current inside temperature, a current transmissivity value of the electrochromic device, a target transmissivity value of the electrochromic device, and a transition rate. 
     
     
         15 . The window controller of  claim 14 , wherein the microcontroller is further configured to modify the command voltage signal based on one or more other input, feedback, or control signals. 
     
     
         16 . The window controller of  claim 15 , wherein the microcontroller modifies the command voltage signal based at least in part on a voltage feedback signal that is itself based on a detected actual level of the effective DC voltage applied across the optically-switchable device. 
     
     
         17 . The window controller of  claim 15 , wherein the microcontroller modifies the command voltage signal based at least in part on a current feedback signal that is itself based on a detected current transmitted through the optically-switchable device. 
     
     
         18 . The window controller of  claim 15 , wherein the window controller further comprises one or more communication interfaces. 
     
     
         19 . The window controller of  claim 18 , wherein:
 the window controller is configured to communicate with a network controller;   the network controller is configured to communicate and control a plurality of window controllers; and   the microcontroller is configured to modify the command voltage signal based on input from the network controller.   
     
     
         20 . The window controller of  claim 19 , wherein:
 the window controller or network controller is configured to communicate with a building management system; and   the microcontroller is configured to modify the command voltage signal based on input from the building management system.   
     
     
         21 . The window controller of  claim 19 , wherein:
 the window controller or network controller is configured to communicate with one or more lighting systems, heating systems, cooling systems, ventilation systems, power systems, and/or security systems; and   the microcontroller is configured to modify the command voltage signal based on input from the one or more lighting systems, heating systems, cooling systems, ventilation systems, power systems, and/or security systems.   
     
     
         22 . The window controller of  claim 19 , wherein:
 the window controller is configured to communicate with one or more photodetectors; and   the microcontroller is configured to modify the command voltage signal based on input from the one or more photodetectors.   
     
     
         23 . The window controller of  claim 19 , wherein:
 the window controller is configured to communicate with one or more temperature sensors; and   the microcontroller is configured to modify the command voltage signal based on input from the one or more temperature sensors.   
     
     
         24 . The window controller of  claim 19 , wherein:
 the window controller or network controller is configured to communicate with one or more manual user-input devices; and   the microcontroller is configured to modify the command voltage signal based on input from one or more of the manual user-input devices.   
     
     
         25 . A system comprising:
 a plurality of windows, each window comprising an optically-switchable device on a substantially transparent substrate;   a network controller configured to control a plurality of window controllers;   a plurality of window controllers, each window controller comprising:
 a command-voltage generator configured to generate a command voltage signal; and 
 a pulse-width-modulated-signal generator configured to generate a pulse-width-modulated signal based on the command voltage signal, the command voltage signal being based at least in part and at least at certain times on an input received from the network controller, the pulse-width-modulated signal configured to drive a respective one or more of the optically-switchable devices, 
 one or more communication interfaces that enable the window controller to communicate with the network controller; 
 wherein:
 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 power component is configured to deliver a first pulse during each active portion of the first duty cycle; 
 the second power component is configured to deliver a second pulse during each active portion of the second duty cycle; and 
 during operation, the first pulses are applied to a first conductive electrode layer of the optically-switchable device and the second pulses are applied to a second conductive electrode layer of the optically-switchable device; wherein the relative durations of the active portions of the first and second duty cycles 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. 
 
   
     
     
         26 . The system of  claim 25 , wherein each substantially transparent substrate is configured in an IGU. 
     
     
         27 . The system of  claim 26 , wherein one or more of the window controllers are located at least partially within a seal of a respective IGU. 
     
     
         28 . The system of  claim 26 , wherein the optically-switchable device is an electrochromic device formed on a surface of the substantially transparent substrate and adjacent an interior volume of the IGU. 
     
     
         29 . The system of  claim 25 , wherein, for each window controller:
 the first duty cycle has a first time period and a first voltage magnitude;   the second duty cycle has a second time period and a second voltage magnitude;   the first time period equals the second time period; and   the first voltage magnitude equals the second voltage magnitude.   
     
     
         30 . The system of  claim 29 , wherein each window controller further comprises first and second inductors that couple the first and second power components to the optically-switchable device, wherein the voltage applied across the optically-switchable device resulting from the applied first and second power components is effectively a DC voltage. 
     
     
         31 . The system of  claim 30 , wherein:
 the active portion of the first duty cycle comprises a first fraction of the first time period; and   the active portion of the second duty cycle comprises a second fraction of the second time period.   
     
     
         32 . The system of  claim 31 , wherein:
 the magnitude of the voltage applied to a first conductive layer of the optically-switchable device is substantially proportional to the product of the first fraction and the first voltage magnitude;   the magnitude of the voltage applied to a second conductive layer of the optically-switchable device is substantially proportional to the product of the second fraction and the second voltage magnitude; and   the effective DC voltage applied across the optically-switchable device is substantially equal to the difference between the magnitude of the voltage applied to the first conductive layer and the magnitude of the voltage applied to the second conductive layer.   
     
     
         33 . The system of  claim 25 , wherein the command-voltage generator of each window controller includes a microcontroller configured to generate the command voltage signal. 
     
     
         34 . The system of  claim 33 , wherein the microcontroller generates the respective command voltage signal based at least in part on a voltage feedback signal that is itself based on an effective DC voltage applied across the respective optically-switchable device. 
     
     
         35 . The system of  claim 33 , wherein the microcontroller generates the respective command voltage signal based at least in part on a current feedback signal that is itself based on a detected current transmitted through the respective optically-switchable device. 
     
     
         36 . The system of  claim 33 , wherein each window controller further comprises a memory device configured to store one or more drive parameters. 
     
     
         37 . The system of  claim 36 , wherein the drive parameters include one or more of a current outside temperature, a current inside temperature, a current transmissivity value of the electrochromic device, a target transmissivity value of the electrochromic device, and a transition rate. 
     
     
         38 . The system of  claim 37 , wherein the microcontroller modifies the command voltage signal based at least in part on a voltage feedback signal that is itself based on a detected actual level of the effective DC voltage applied across the respective optically-switchable device. 
     
     
         39 . The system of  claim 37 , wherein the microcontroller modifies the command voltage signal based at least in part on a current feedback signal that is itself based on a detected current transmitted through the respective optically-switchable device. 
     
     
         40 . The system of  claim 33 , wherein:
 the network controller is configured to communicate with a building management system; and   the microcontroller of each window controller is configured to modify the command voltage signal based on input from the building management system.   
     
     
         41 . The system of  claim 33 , wherein:
 the network controller is configured to communicate with one or more lighting systems, heating systems, cooling systems, ventilation systems, power systems, and/or security systems; and   the microcontroller of each window controller is configured to modify the command voltage signal based on input from the one or more lighting systems, heating systems, cooling systems, ventilation systems, power systems, and/or security systems.   
     
     
         42 . The system of  claim 33 , wherein:
 each window controller is configured to communicate with one or more photodetectors; and   the respective microcontroller is configured to modify the command voltage signal based on input from the one or more photodetectors.   
     
     
         43 . The system of  claim 33 , wherein:
 each window controller is configured to communicate with one or more temperature sensors; and   the respective microcontroller is configured to modify the command voltage signal based on input from the one or more temperature sensors.   
     
     
         44 . The system of  claim 33 , wherein:
 the network controller is configured to communicate with one or more manual user-input devices; and   the microcontroller of each window controller is configured to modify the command voltage signal based on input from one or more of the manual user-input devices.