Method for operating a compressor
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Solution Overview
Problem
Conventional air conditioning and refrigeration systems experience significant variations in load torque during the compression cycle, leading to noise, vibration, and excessive wear on components due to uneven rotor speed, particularly at slow speeds like startup.
Innovation Solution
A method is implemented to obtain a harmonic series representation of the periodic load torque exerted on the rotor and calculate an electromagnetic torque using a torque control input model, allowing the electric motor to compensate for these variations, thereby maintaining a constant speed and minimizing noise and vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional direct drive operation is used, then the compressor can operate continuously, but the rotor speed varies significantly causing noise and vibration
Solution Approach 1:
The system uses a feedback control mechanism where the controller continuously monitors the compression cycle phase and adjusts the electromagnetic torque in real-time based on the detected load torque variations, maintaining stable rotor speed despite periodic compression loads
Solution Approach 2:
The system dynamically changes the electromagnetic torque parameter throughout the compression cycle by calculating and applying compensating torque based on the phase angle, transforming the torque profile to counteract periodic load variations and maintain constant speed
2Object-affected harmful factors
If the motor compensates for load torque variations, then noise and vibration are reduced, but the control system complexity increases
Solution Approach 1:
The system replaces complex mechanical speed regulation mechanisms with an electrical control approach, using the electric motor's inherent torque control capability and a processor to calculate and apply compensating torque, thereby reducing mechanical complexity while achieving noise and vibration reduction
3Manufacturing precision
If electromagnetic torque is calculated using harmonic series representation, then speed regulation precision is improved, but the computational requirements increase
Solution Approach 1:
The system applies partial action by using a truncated harmonic series representation that captures the dominant periodic load torque components without requiring the full spectral decomposition, achieving sufficient speed regulation precision with reduced computational effort
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 effectively reduces noise and vibration, and minimizes wear on system components by regulating the compressor motor speed to match the periodic load torque variations, enhancing operational stability and efficiency.
Implementation Method 1
calculating an electromagnetic torque using a torque control input model... operating the electric motor to generate the calculated electromagnetic torque on the rotor
Data Source
AI summary
A method of operating a compressor includes obtaining a harmonic series representation of speed variation as the rotor rotates through each revolution. The method includes regulating an electric motor to compensate for or cancel out the periodic speed variation. Specifically, the method includes calculating an electromagnetic torque using a torque control input model based on the speed error and the harmonic series representation of the speed error. The operation of the electric motor is then adjusted such that the electromagnetic torque applied by the motor cancels out the speed variation such that noise and vibrations are minimized.