Compressor Motor Control for Oil Foaming and Heating Time
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Solution Overview
Problem
Compressors experience oil foaming when rapidly driven after a long period of low temperature, leading to oil scarcity and wear on bearing parts, and existing heating methods, such as crank case heaters and wiring heating, take too long to heat the compressor casing effectively.
Innovation Solution
A compressor control method that uses temperature sensors to adjust the motor's heat radiation by increasing the electric current during low-speed operation if the oil temperature is below a reference temperature, reducing oil foaming and accelerating the heating process by performing a loss operation until the oil reaches a predetermined temperature for normal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the compressor is driven at high speed after a long period of low temperature, then the compressor can quickly reach normal operating conditions, but oil foaming occurs and oil is discharged through the outlet port
Solution Approach 1:
The patent applies dynamics by making the compressor speed variable rather than fixed. The control part adjusts the motor operating speed based on oil temperature conditions: low speed when oil temperature is below the reference temperature to prevent foaming, and normal speed when oil temperature reaches the reference temperature. This dynamic speed adjustment resolves the contradiction between quick heating and oil retention.
2Temperature
If the casing is heated using a crank case heater or wiring heating method, then the oil temperature increases to prevent foaming, but the waiting time until heating is completed becomes too long
Solution Approach 1:
The patent applies self-service by using the motor part itself as the heating source rather than external heating devices. The motor part operates at low speed and generates heat through electromagnetic losses (I²R heating in the windings), which directly heats the oil in the casing. This self-heating mechanism eliminates the need for separate heating systems and significantly reduces the heating time while preventing oil foaming.
3Loss of time
If the motor part operates at normal speed to quickly heat the oil, then the heating time is reduced, but oil foaming occurs and bearing parts become worn
Solution Approach 1:
The patent applies parameter changes by modifying the motor operating speed parameter based on oil temperature conditions. When oil temperature is below the reference temperature, the motor operates at low speed to prevent foaming and bearing wear. When oil temperature reaches the reference temperature, the motor operates at normal speed for efficient compression. This parameter adjustment based on temperature conditions resolves the contradiction between heating speed and preventing harmful effects.
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
This approach reduces oil foaming, prevents premature oil discharge, and shortens the time to reach normal operating conditions, improving compressor reliability and user satisfaction by efficiently heating the compressor during low-speed operation.
Implementation Method 1
perform a loss operation, in which an amount of heat radiation of the motor part is increased
Implementation Method 2
a motor part installed at an inside of the casing to provide the compressing part with a driving force
Implementation Method 3
a sensor part having at least one temperature sensor to, if an operation command is input, sense temperature of the oil
Data Source
AI summary
A compressor capable of reducing oil foaming and reducing the waiting time taken until the heating of the compressor is completed, and a method of controlling the same, the method of controlling a compressor including sensing temperature of the oil in the compressor, if the temperature of the oil is below a reference temperature, performing a loss operation, in which an amount of heat radiation of the motor part is increased, while operating the motor part at a low speed, and if the temperature of the oil increases to be equal to or higher then reference temperature, performing an efficiency operation by converting an operation of the motor to a normal operation.