Date of Award
Master of Science (MS)
Collins, Edward R
Bridgwood , Michael A
Komo , John J
In some circumstances, voltage flicker due to the inrush current of residential heat pump can be a fairly visible to the residents as a slight flashing of the household's lights during the compressor starting event. The voltage flicker problem is caused by a variable contribution from sizable equivalent power system impedances and considerable inrush currents drawn by compressors. While this is not a new problem, and there are technologies on the market that attempt to alleviate the voltage flicker issue, no current solution attempts to correct for the problem at its root cause.
This thesis presents a device designed to utilize the time proven method of using shunt capacitance for voltage correction and dynamically adapt it to the voltage flicker event by, in essence, learning the amount of capacitance needed to correctly compensate the voltage and virtually eliminate any flicker. The voltage flicker suppression device is aimed at being a one size fits all, cost effective solution for not only new construction, but one that can be easily retro-fit to existing HVAC installations where voltage flicker is an issue.
To better understand the obstacles and requirements that such a device can be confronted with, background information is presented to address the characteristics of residential heat pump and their compressors, as well as contributing factors from residential power services. A human factors flicker study was conducted and is offered in an effort to experimentally determine the threshold of visible flicker and thus derive the level of voltage compensation required of the device.
The laboratory results presented within this thesis will demonstrate that, with no prior knowledge of the compressor or power system characteristics, the voltage flicker suppression device is capable of adapting to the required capacitance needed to ensure that the voltage flicker is corrected for and the visible light flicker is minimized.
There are several limitations in terms of voltage compensation abilities that must be overcome when deciding the electrical location and controller characteristics of the device while maintaining an acceptable bottom line. A discussion of these limitations is conducted in order to demonstrate the continuing work required for the device to ultimately meet the design goals.
Fox, John, "A Voltage Flicker Suppression Device for Residential Air Conditioners and Heat Pumps" (2009). All Theses. 674.