Compressor, and control method for same
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing compressors face overcurrent issues in the fan motor due to changes in ambient temperature and air density, leading to potential motor tripping and overload.
Innovation Solution
A compressor control system that adjusts the upper limit frequency of the fan motor based on initial cooling gas temperatures detected by temperature sensors, setting the frequency to prevent overcurrent by maintaining a safe current level regardless of ambient temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the upper limit frequency of the fan motor is set high to improve cooling performance, then the cooling efficiency is improved, but the fan motor current increases and may cause overcurrent tripping
Solution Approach 1:
The upper limit frequency of the fan motor is changed from a fixed value to a dynamic value that varies with ambient temperature. The control unit adjusts the upper limit frequency based on detected ambient temperature, allowing the frequency to be higher when temperature is high (improving cooling) and lower when temperature is low (preventing overcurrent), thus resolving the contradiction between cooling efficiency and motor protection
Solution Approach 2:
The patent changes the parameter of upper limit frequency from constant to variable based on ambient temperature. By making this parameter changeable according to environmental conditions, the system achieves both improved cooling when needed and prevented overcurrent when ambient temperature is low, solving the technical contradiction
2Power
If the fan motor rotational speed is increased to enhance heat removal, then the cooling capacity is improved, but the power consumption and current draw increase proportionally to the cube of the frequency
Solution Approach 1:
The fan motor operational frequency is made dynamic rather than fixed, adjusting according to ambient temperature conditions. This allows the system to achieve high cooling capacity when high frequency is needed while avoiding excessive power consumption when ambient temperature is already low, thus resolving the contradiction between cooling capacity and energy use
3Reliability
If a fixed upper limit frequency is set to protect the fan motor from overcurrent, then the motor protection is ensured, but the cooling performance deteriorates when ambient temperature is high
Solution Approach 1:
The upper limit frequency is transformed from a static protective constraint to a dynamic parameter that adapts to ambient temperature. When ambient temperature is high, the upper limit frequency is raised to maintain cooling performance; when ambient temperature is low, it is lowered to maintain motor protection, thus resolving the contradiction between protection and performance
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
Prevents overcurrent in the fan motor by dynamically adjusting the upper limit frequency, ensuring stable operation even with varying ambient conditions.
Implementation Method 1
a heat exchanger (gas cooler or oil cooler) that exchanges heat between a cooled target and external air, by driving the cooling fan
Implementation Method 2
a temperature sensor that detects an initial cooling gas temperatures that are temperatures of the cooling gas not having been subject to heat removing for the heat exchanger
Data Source
AI summary
A compressor includes: a compressor body that suctions and compresses a gas to be compressed; heat exchangers that circulate a cooled target inside the heat exchangers to cool the cooled target; a fan that is driven by a fan motor and that sends a cooling gas to the heat exchangers to remove heat; a temperature sensor that detects an initial cooling gas temperature that is a temperature of the cooling gas not having been subject to heat removing for the heat exchangers; and a control unit that is capable of setting an upper limit frequency that is an upper limit for controlling a rotational frequency of the fan motor. The control unit sets the upper limit frequency to a rotational frequency equal to or lower than a frequency at which current at an acceptable current level is supplied to the fan motor, at each of the initial cooling gas temperatures detected by the temperature sensor.