Control system for thermoelectric devices

Patent metadata

Field	Value
Publication number	US-9739512-B2
Application number	US-201113102896-A
Country	US
Kind code	B2
Filing date	May 6, 2011
Priority date	Aug 9, 2010
Publication date	Aug 22, 2017
Grant date	Aug 22, 2017

Abstract

A system and method to control a thermoelectric device using a microcontroller is provided. The system and method include a temperature sensor operatively coupled to a microcontroller that has a central processing unit, at least one memory device, and a module for generating at least one pulse width modulation signal. The at least one pulse width modulation signal generated by the microcontroller has “ON” and “OFF” states to drive the thermoelectric device.

First claim

What is claimed is:

1. A control system for a thermoelectric device, the control system comprising:
a temperature sensor effective to sense a temperature; and
a microcontroller operatively coupled to the temperature sensor, wherein the microcontroller comprises a central processing unit, at least one memory device, and a module effective to generate at least one pulse width modulation signal,
wherein the at least one pulse width modulation signal, generated by the microcontroller, is effective to drive the thermoelectric device, and wherein the microcontroller is configured to:
determine whether a first mode of operation related to hysteresis, or a second mode of operation related to high and low set temperatures, is selected;
when the first mode is selected, set an upper hysteresis temperature limit and a lower hysteresis temperature limit and dynamically adapt a pulse width of the at least one pulse width modulation signal responsive to the sensed temperature such that the pulse width corresponds to a first duty cycle based on the upper hysteresis temperature limit and the lower hysteresis temperature limit; and
thereafter, when the second mode is selected, set a high set temperature and a low set temperature and dynamically adapt the pulse width of the at least one pulse width modulation signal responsive to the sensed temperature such that the pulse width corresponds to a second duty cycle based on the high set temperature and the low set temperature,
wherein to dynamically adapt the pulse width of the at least one pulse width modulation signal such that the pulse width corresponds to the second duty cycle, the microcontroller is effective to:
calculate a reference temperature, wherein the reference temperature is between the high set temperature and the low set temperature;
compare the sensed temperature to the reference temperature to determine a difference between the sensed temperature and the reference temperature;
determine a dynamic percentage change of the duty cycle, wherein the dynamic percentage change of the duty cycle varies based on parameters of the thermoelectric device, based on the difference between the sensed temperature and the reference temperature, and based on an atmospheric temperature;
increase the second duty cycle by the dynamic percentage when the sensed temperature exceeds the reference temperature; and
decrease the second duty cycle by the dynamic percentage when the sensed temperature is less than or equal to the reference temperature.

2. The control system of claim 1 , wherein the at least one pulse width modulation signal comprises at least a first state and a second state, the first state signaling that the thermoelectric device should be turned on, and the second state signaling that the thermoelectric device should be turned off.

3. The control system of claim 2 , wherein the at least one pulse width modulation signal comprises at least two separate first states and at least two separate second states, and wherein the thermoelectric device is turned on at least twice and turned off at least twice.

4. The control system of claim 1 , wherein the temperature sensor generates at least one analog temperature signal, wherein the microcontroller further comprises an analog-to-digital converter operatively coupled to the temperature sensor, and wherein the analog-to-digital converter converts the at least one analog temperature signal into at least one digital temperature signal.

5. The control system of claim 4 , further comprising an analog signal conditioner coupled between the temperature sensor and the analog-to-digital converter.

6. The control system of claim 1 , further comprising a display and at least one input device coupled to the microcontroller.

7. The control system of claim 1 , further comprising a power amplifier coupled between the module and the thermoelectric device, wherein the power amplifier is effective to amplify the at least one pulse width modulation signal.

8. The control system of claim 1 , further comprising an external clock effective to provide an independent time base for generation of the at least one pulse width modulation signal.

9. A method of controlling a thermoelectric device, the method comprising:
providing a microcontroller operatively coupled to a temperature sensor, the microcontroller comprising a central processing unit, at least one memory device, and a module operatively coupled to at least one thermoelectric device;
sensing a temperature with the temperature sensor;
generating at least one pulse width modulation signal with the module of the microcontroller;
transmitting the at least one pulse width modulation signal from the microcontroller to the thermoelectric device;
driving the thermoelectric device in accordance with the at least one pulse width modulation signal effective to generate a pulse with a pulse width;
determining whether a first mode of operation related to hysteresis, or a second mode of operation related to high and low set temperatures, is selected;
when the first mode is selected, setting an upper hysteresis temperature limit and a lower hysteresis temperature limit and dynamically adapting the pulse width of the at least one pulse width modulation signal responsive to the sensed temperature such that the pulse width corresponds to a first duty cycle based on the upper hysteresis temperature limit and the lower hysteresis temperature limit; and
thereafter, when the second mode is selected, setting a high set temperature and a low set temperature and dynamically adapting the pulse width of the at least one pulse width modulation signal responsive to the sensed temperature such that the pulse width corresponds to a second duty cycle based on the high set temperature and the low set temperature,
wherein dynamically adapting the pulse width of the at least one pulse width modulation signal such that the pulse width corresponds to the second duty cycle, comprises:
calculating a reference temperature, wherein the reference temperature is between the high set temperature and the low set temperature;
comparing the sensed temperature to the reference temperature to determine a difference between the sensed temperature and the reference temperature;
determining a dynamic percentage change of the duty cycle, wherein the dynamic percentage change of the duty cycle varies based on parameters of the thermoelectric device, based on the difference between the sensed temperature and the reference temperature, and based on an atmospheric temperature;
increasing the second duty cycle by the dynamic percentage based on a determination that the sensed temperature exceeds the reference temperature; and
decreasing the second duty cycle by the dynamic percentage based on a determination that the sensed temperature is less than the reference temperature.

10. The method of claim 9 , wherein the at least one pulse width modulation signal comprises a first state and a second state, the first state signaling that the thermoelectric device should be turned on, and the second state signaling that the thermoelectric device should be turned off.

11. The method of claim 10 , wherein the at least one pulse width modulation signal comprises at least two separate first states and at least two separate second states, and wherein the thermoelectric device is turned on at least twice and turned off at least twice.

12. The method of claim 9 , further comprising converting at least one analog temperature signal into at least one digital temperature signal, and using the at least one digital temperature signal to generate the at least one pulse width modulation signal.

13.

Assignees

• Rao Anantha Krishnan Rama
• Empire Technology Dev Llc

Inventors

• Rao Anantha Krishnan Rama

Classifications

• F25B2700/2104

  of an indoor room or compartment · CPC title

• F25B2321/0212

  of electric power, current or voltage · CPC title

• F25B21/02 Primary

  using Peltier effect; using Nernst-Ettinghausen effect · CPC title