System and method of controlling a variable-capacity compressor

1. A system comprising:

a variable-capacity compressor operable in a first capacity mode and in a second capacity mode that is higher than the first capacity mode; and

a control module configured to switch the variable-capacity compressor between the first capacity mode and the second capacity mode based on a demand signal from a thermostat,

wherein the control module determines a number of previous consecutive operating cycles of the variable-capacity compressor in the first capacity mode within a predetermined period of time and operates the variable-capacity compressor in the second capacity mode in response to the number of previous consecutive operating cycles of the variable-capacity compressor in the first capacity mode within the predetermined period of time exceeding a predetermined threshold.

2. The system of claim 1 , wherein the control module operates the variable-capacity compressor in the second capacity mode in response to an average runtime of the variable-capacity compressor in the first capacity mode during the predetermined period of time being less than a predetermined value.

3. The system of claim 1 wherein the thermostat includes an indoor relative humidity sensor that generates indoor relative humidity data corresponding to an indoor relative humidity.

4. The system of claim 3 , wherein the control module operates the variable-capacity compressor in the second capacity mode in response to the indoor relative humidity exceeding a predetermined humidity.

5. The system of claim 3 , wherein the control module determines a slope of the indoor relative humidity and operates the variable-capacity compressor in the second capacity mode based on the slope of the indoor relative humidity.

6. The system of claim 3 , wherein the control module operates the variable-capacity compressor in the second capacity mode in response to a previous operating cycle being in the second capacity mode and the indoor relative humidity exceeding a predetermined humidity.

7. The system of claim 3 , wherein the control module sets a runtime of the variable-capacity compressor in the second capacity mode according to the indoor relative humidity.

8. The system of claim 1 , wherein the thermostat is further configured to measure an air temperature, receive a setpoint temperature, and generate the demand signal based on a difference between the air temperature and the setpoint temperature.

9. The system of claim 1 , wherein the control module includes an outdoor-air-temperature sensor that generates outdoor-air-temperature data corresponding to an outdoor-air-temperature.

10. The system of claim 9 , wherein the control module sets a runtime of the variable-capacity compressor in the second capacity mode according to the outdoor-air-temperature.

11. A method of controlling a variable-capacity compressor, comprising:

receiving, with a control module, a demand signal from a thermostat;

operating, with the control module, a variable-capacity compressor based on the demand signal, the variable-capacity compressor being operable in a first capacity mode and in a second capacity mode that is higher than the first capacity mode;

determining, with the control module, a number of previous consecutive operating cycles of the variable-capacity compressor in the first capacity mode within a predetermined period of time; and

operating, with the control module, the variable-capacity compressor in the second capacity mode in response to the number of previous consecutive operating cycles of the variable-capacity compressor in the first capacity mode within the predetermined period of time exceeding a predetermined threshold.

12. The method of claim 11 , further comprising operating, with the control module, the variable-capacity compressor in the second capacity mode in response to an average runtime of the variable-capacity compressor in the first capacity mode during the predetermined period of time being less than a predetermined value.

13. The method of claim 11 , wherein the thermostat includes an indoor relative humidity sensor that generates indoor relative humidity data corresponding to an indoor relative humidity.

14. The method of claim 13 , further comprising operating, with the control module, the variable-capacity compressor in the second capacity mode in response to the indoor relative humidity exceeding a predetermined humidity.

15. The method of claim 13 , further comprising operating, with the control module, the variable-capacity compressor in the second capacity mode based on a slope of the indoor relative humidity.

16. The method of claim 13 , further comprising operating, with the control module, the variable-capacity compressor in the second capacity mode in response to a previous operating cycle being in the second capacity mode and the indoor relative humidity exceeding a predetermined humidity.

17. The method of claim 13 , further comprising setting, with the control module, a runtime of the variable-capacity compressor in the second capacity mode according to the indoor relative humidity.

18. The method of claim 11 , wherein the thermostat is configured to measure an air temperature, receive a setpoint temperature, and generate the demand signal based on a difference between the air temperature and the setpoint temperature.

19. The method of claim 11 , wherein an outdoor-air-temperature sensor generates outdoor-air-temperature data corresponding to an outdoor-air-temperature.

20. The method of claim 19 , setting, with the control module, a runtime of the variable-capacity compressor in the second capacity mode according to the outdoor-air-temperature.