Digital power supply with wireless monitoring and control
Provided is an apparatus and method for a digital power supply that can provide independent power control for two or more electrical loads. Some disclosed embodiments provide continuous, variable power and other disclosed embodiments provide discrete power levels. Disclosed embodiments may reduce the magnitude of harmonic currents and/or flicker introduced into a power system. Embodiments include a microprocessor that delivers power to electric loads using phase-controlled AC current. In some embodiments, the microprocessor may calculate a power array corresponding to a requested power for each electric load. Logic is provided for populating the power array in a pattern that reduces the magnitude of harmonic currents and flicker. Portions of the disclosure include a band controller for delivering power to achieve and maintain a desired target temperature, and a wireless controller for controlling temperature from a remote device.
1. An electric grill having a digital power supply, comprising:
at least one heating element connected through a triac to a voltage line;
a microprocessor in electronic communication with the triac; wherein the microprocessor is configured to deliver a first, second, or third discrete power level to the heating element by activating or deactivating the triac;
at least one temperature sensing device for measuring the temperature at a position in the electric grill, the temperature sensing device being in electronic communication with the microprocessor and configured to communicate the sensed temperature to the microprocessor; and
a band controller; the band controller being configured to receive a desired target temperature and determine an upper temperature band and a lower temperature band, the range between the upper temperature band and the lower temperature band being based on the desired target temperature;
wherein the band controller is further configured to raise the lower temperature band and the upper temperature band relative to the desired target temperature as the desired target temperature increases; and
wherein the microprocessor is further configured to deliver the first discrete power level when the sensed temperature is below the lower temperature band; to deliver the second discrete power level when the sensed temperature is between the lower temperature and the upper temperature band; and to deliver the third discrete power level when the sensed temperature is above the upper temperature band.
2. The electric grill of claim 1 , wherein the first discrete power level is 100%, the second discrete power level is 50%, and wherein the microprocessor is further configured to deliver a third discrete power level of 0% in response to a sensed temperature above the upper temperature band.
3. The electric grill of claim 2 , wherein the microprocessor is adapted and configured to continuously monitor the temperature received from the temperature sensing device, and wherein the microprocessor is further adapted and configured to deliver 100% power to the heating element until the lower temperature band is reached.
4. The electric grill of claim 3 , wherein the microprocessor is further adapted and configured to deliver 50% power to the heating element until the upper temperature band is reached, and wherein the microprocessor delivers 50% power by alternately blocking and allowing a wave of ac current to pass to the heating element.
5. The electric grill of claim 4 , wherein the microprocessor is further adapted and configured to deliver 0% power to the heating element when the upper temperature band is reached.
6. The electric grill of claim 1 , wherein the band controller is adapted and configured to dynamically lower the temperature bands for a lower desired target temperature and raise the temperature bands for a higher desired target temperature.
7. The electric grill of claim 1 , wherein a desired target temperature of 250 F has a lower temperature band of 25 F below the desired target temperature and an upper temperature band equal to the desired target temperature.
8. The electric grill of claim 1 , wherein a desired target temperature between 250 F and 400 F has a lower temperature band of 10 F below the desired target temperature and an upper temperature band of 10 F above the desired target temperature.
9. The electric grill of claim 1 , wherein a desired target temperature above 400 F has a lower temperature band equal to the desired target temperature and an upper temperature band of 15 F above the desired target temperature.
10. The electric grill of claim 1 , wherein the band controller is further configured to set the upper temperature band to coincide with the desired target temperature for a first desired target temperature.
11. The electric grill of claim 10 , wherein the band controller is further configured to set a second desired target temperature as the midpoint between the lower temperature band and the upper temperature band.
12. The electric grill of claim 11 , wherein the band controller is further configured to set the lower temperature band to coincide with a third desired target temperature.
13. The electric grill of claim 12 , wherein the second desired target temperature is higher than the first desired target temperature, and wherein the third desired target temperature is higher than the second desired target temperature.
14. The electric grill of claim 12 , wherein the first desired target temperature is below 250 F, the second desired target temperature is between 250 F and 400 F, and the third desired target temperature is above 400 F.
15. The electric grill of claim 1 , wherein the band controller is further configured to set a first range between the lower temperature band and the upper temperature band for a first desired target temperature, a second range for a second desired target temperature, and a third range for a third desired target temperature.
16. The electric grill of claim 15 , wherein the first range is larger than the second range, and the second range is larger than the third range.
17. The electric grill of claim 15 , wherein the first range is 25 F, the second range is 20 F, and the third range is 15 F.
18. The electric grill of claim 15 , wherein the first desired target temperature is below 250 F, the second desired target temperature is between 250 F and 400 F, and the third desired target temperature is above 400 F.