Driver for electrochromic glass unit

Patent metadata

Field	Value
Publication number	US-9563097-B2
Application number	US-201614994091-A
Country	US
Kind code	B2
Filing date	Jan 12, 2016
Priority date	Jan 12, 2015
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

A method for controlling an electrochromic device is provided. The method includes applying a constant supply current to the electrochromic device and determining an amount of charge transferred to the electrochromic device, as a function of time and current supplied to the electrochromic device. The method includes ceasing the applying the constant supply current, responsive to a sense voltage reaching a sense voltage limit and applying one of a variable voltage or a variable current to the electrochromic device to maintain the sense voltage at the sense voltage limit, responsive to the sense voltage reaching the sense voltage limit. The method includes terminating the applying the variable voltage or the variable current to the electrochromic device, responsive to the determined amount of charge reaching a target amount of charge.

First claim

What is claimed is:

1. A method for controlling an electrochromic device, comprising:
applying a constant supply current to the electrochromic device;
determining an amount of charge transferred to the electrochromic device, as a function of time and current supplied to the electrochromic device;
ceasing the applying the constant supply current, responsive to a sense voltage reaching a sense voltage limit;
applying one of a variable voltage or a variable current to the electrochromic device to maintain the sense voltage at the sense voltage limit, responsive to the sense voltage reaching the sense voltage limit; and
terminating the applying the variable voltage or the variable current to the electrochromic device, responsive to the determined amount of charge reaching a target amount of charge.

2. The method of claim 1 , wherein terminating occurs after reaching a desired transmissivity of the electrochromic device equating to the target amount of charge.

3. The method of claim 1 , further comprising:
measuring the sense voltage of the electrochromic device; and
measuring the current supplied to the electrochromic device, wherein determining the amount of charge is based on summing digital values of the current over a span of time.

4. The method of claim 1 , wherein determining the amount of charge transferred to the electrochromic device comprises:
integrating, over time, the current supplied to the electrochromic device.

5. The method of claim 1 , wherein once the amount of charge transferred equals the target amount of charge to be transferred the driver starts a four wire open circuit voltage process.

6. The method of claim 1 , further comprising:
reversing a polarity of a reversible constant current supply, wherein the reversible constant current supply applies the constant supply current with the reversed polarity to the electrochromic device;
reversing a polarity of a reversible variable voltage supply, wherein the reversible variable voltage supply applies the variable voltage with the reversed polarity to the electrochromic device, and wherein the sense voltage limit is zero volts; and
delaying the terminating for a predetermined amount of time during which the sense voltage is held at zero volts.

7. The method of claim 6 , wherein the sense voltage is held at zero volts to rezero the driver as to the state of charge of the electrochromic device.

8. The method of claim 1 , wherein determining the amount of charge transferred to the electrochromic device further comprises:
applying analog to digital conversion to the current supplied to the electrochromic device, to produce a digital value of the current supplied to the electrochromic device; and
adding values from a time series of the digital value of the current supplied to the electrochromic device.

9. The method of claim 1 , wherein:
the constant supply current is supplied to bus bars of the electrochromic device;
the variable voltage or the variable current is supplied to the bus bars; and
the sense voltage is measured from sense voltage terminals of the electrochromic device located elsewhere than the bus bars.

10. The method of claim 1 wherein the sense voltage is measured from an edge of the electrochromic device.

11. The method of claim 1 , further comprising:
monitoring the sense voltage; and
applying one of a charge or a discharge to the electrochromic device, responsive to a deviation of the sense voltage, after a predetermined relaxation time, by more than a predetermined relaxation amount of voltage.

12. The method of claim 1 wherein if the state of charge does not match the target s a sequestration process is initiated.

13. The method of claim 1 , wherein a sequestration process is initiated every time a fully bleached state is met.

14. An electronic driver for an electrochromic device, comprising:
a power supply; and
a power supply control module configured to perform actions comprising:
supplying a constant current from the power supply to the electrochromic device;
stopping the supplying the constant current when one of a sense voltage of the electrochromic device attains a sense voltage limit or an amount of charge transferred to the electrochromic device attains a target amount of charge; and
controlling one of a variable voltage or a variable current from the power supply to the electrochromic device to maintain the sense voltage at the sense voltage limit while the amount of charge transferred to the electrochromic device is less than the target amount of charge.

15. The electronic driver of claim 14 , further comprising at least one set of sense voltage terminals.

16. The electronic driver of claim 15 , wherein the at least one set of sense voltage terminals is located elsewhere than a location of the bus bars.

17. The electronic driver of claim 15 , wherein the at least one set of sense voltage terminals is connected to an interior region of the electrochromic device.

18. The electronic driver of claim 15 , wherein the at least one set of sense voltage terminals is connected along an edge of the electrochromic device.

19. The electronic driver of claim 14 , further comprising:
the power supply arranged to reverse polarity via one of a relay, a solid-state switch or a multiple range operation of the power supply.

20. The electronic driver of claim 14 , further comprising:
an integrator module, coupled to the power supply module and arranged to integrate over time a current supplied to the electrochromic device, wherein the amount of charge transferred to the electrochromic device is based on an output of the integrator module.

21. The electronic driver of claim 14 , further comprising:
the power supply control module configured to control the variable voltage or the variable current from the power supply to the electrochromic device to hold the sense voltage at zero volts for a predetermined time span, for a full discharge of the electrochromic device.

22. The electronic driver of claim 14 , further comprising:
the power supply control module configured to monitor the sense voltage and configured to charge or discharge the electrochromic device when the sense voltage deviates after a predetermined relaxation time by more than a predetermined voltage.

23. The electronic driver of claim 14 , further comprising:
an analog-to-digital converter, coupled to the power supply control module and configured to couple to sense voltage terminals of the electrochromic device, the analog-to-digital converter arranged to produce a value of the sense voltage, wherein the sense voltage terminals are distinct from bus bars of the electrochromic device.

24. An electronic driver for an electrochromic device, comprising:
a voltage detecting circuit configured to measure a sense voltage of sense voltage terminals of the electrochromic device;
a reversible constant current supply configured to supply a constant current to the electrochromic device until one of the sense voltage achieves a sense voltage limit or an amount of charge transferred to the electrochromic device achieves a target amount of charge; and
a reversible variable voltage supply configured to supply a variable voltage to the electrochromic device to keep the sense voltage at the sense voltage limit, responsive to the sense voltage achieving the sense voltage limit, until the elapsed time reaches a predetermined time duration.

25. The electro

Assignees

• Kinestral Tech Inc

Inventors

• Ziebarth Jonathan
• Bergh Howard S

Classifications

• G02F1/163 Primary

  Operation of electrochromic cells, e.g. electrodeposition cells; Circuit arrangements therefor · CPC title

• E06B2009/2464

  featuring transparency control by applying voltage, e.g. LCD, electrochromic panels · CPC title

• B60R1/088

  using a cell of electrically changeable optical characteristic, e.g. liquid-crystal or electrochromic mirrors · CPC title

• G02F1/155

  Electrodes · CPC title

• G09G3/16

  by control of light from an independent source · CPC title