Compressor Motor Drive Parameter Control for Lubricant Quality
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Solution Overview
Problem
Compressor systems face inefficiencies in lubricant refinement due to low discharge temperatures and refrigerant solubility issues, particularly at low pressure and volume ratios, which affect lubricant quality and rheological properties.
Innovation Solution
A compressor system with a controller that varies drive parameters such as pulse width modulation switching frequency, torque/amp ratio, and high-frequency waveform injection to increase motor and drive heat, enhancing lubricant separation and quality by increasing discharge superheat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the compressor operates at low pressure ratios and low volume ratios to improve efficiency, then energy consumption is reduced, but discharge temperature decreases leading to poor lubricant quality
Solution Approach 1:
The patent converts the harmful waste heat from the motor into a beneficial heating source for the lubricant. By positioning the motor within the refrigerant flow path, the heat generated by motor inefficiencies is transferred to the refrigerant, which then heats the lubricant in the sump, improving lubricant quality without compromising motor efficiency
Solution Approach 2:
The patent merges the motor and drive components with the refrigerant flow path by positioning them within the sump area. This integration allows the motor to serve dual purposes: driving the compressor and simultaneously heating the lubricant through its waste heat, which is transferred via the refrigerant flow
2Productivity
If modern refrigerants with higher solubility are used to improve cooling performance, then refrigeration efficiency is enhanced, but lubricant quality deteriorates due to increased refrigerant dissolution
Solution Approach 1:
The patent changes the temperature parameter of the lubricant by using motor waste heat to heat the refrigerant flow path that passes through the sump. This temperature increase reduces refrigerant solubility in the lubricant, maintaining lubricant quality even when using modern high-performance refrigerants with higher solubility characteristics
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution improves lubricant quality and rheological properties by increasing discharge superheat, enhancing lubricant separation and overall compressor efficiency, even at non-optimal operational conditions.
Implementation Method 1
The operation of the motor and the drive may result in inefficiencies at the motor that cause losses that generate waste heat
Implementation Method 2
The waste heat from the motor may be transferred to refrigerant entering the compressor
Implementation Method 3
the one or more drive parameters include at least one of a pulse width modulation switching frequency and a pulse width modulation frequency switching pattern
Implementation Method 4
Increasing the discharge superheat of the compressor is one way of heating the lubricant to refine the lubricant by improving the separation of lubricant from refrigerant
Data Source
AI summary
This disclosure is directed to systems and methods for controlling compressor motors, particularly varying the operation parameters of the motor to provide heat to a lubricant of the motor. The operation parameters include one or more of a pulse width modulation switching frequency, a pulse width modulation frequency switching pattern, or a torque/amp ratio of a drive of the compressor. The efficiency of the motor may be reduced to provide heat, with the heat improving lubricant quality and drive efficiency, to increase an overall efficiency of compressor operations. Methods may include determining a lubricant quality, and determining operational parameters that improve lubricant quality.