Outer Rotor Air Compressor Control for Stable High Discharge
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Solution Overview
Problem
Existing air compressors face challenges in increasing discharge amount without causing motor rotation instability, excessive noise, and load variation, particularly when using outer rotor motors with large sound-generating rotors and limited current supply.
Innovation Solution
Employing an outer rotor motor with a controller that adjusts stator winding voltage based on rotor position, separates current components, and uses vector control to stabilize motor rotation, while incorporating a position sensor and temperature sensor for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of rotations is increased to improve compression efficiency, then discharge amount increases, but generated sound increases
Solution Approach 1:
The patent applies dynamics by making the motor control system adjustable and adaptive. The controller dynamically adjusts voltage based on rotor position and separates current components to optimize motor performance across different operating conditions, enabling discharge amount increase without proportional sound increase
Solution Approach 2:
The patent changes motor control parameters by adjusting voltage applied to stator winding based on rotor position information. It separates current into torque-generating and flux-generating components, independently controlling each to optimize the balance between discharge amount and sound generation
2Productivity
If cylinder diameter or stroke is increased to increase discharge amount, then discharge amount increases, but motor torque requirement increases and stable rotation cannot be obtained
Solution Approach 1:
The patent changes the control parameters by implementing vector control that separates current into d-axis (flux) and q-axis (torque) components. This enables independent optimization of magnetic flux and torque, providing stable motor rotation even when cylinder dimensions are increased for higher discharge amount
Solution Approach 2:
The patent uses feedback from the position sensor to continuously monitor rotor position and adjust voltage accordingly. This closed-loop control stabilizes motor rotation by compensating for load variations that occur when cylinder diameter or stroke is increased
3Use of energy by moving object
If current is limited to suppress power supply within upper limit value, then power consumption is controlled, but discharge amount cannot be increased
Solution Approach 1:
The patent optimizes the use of limited current by changing control parameters to separate current components. By independently controlling flux-generating and torque-generating current components, the system maximizes discharge amount within the power supply's current limits without exceeding the upper limit value
Solution Approach 2:
The patent recovers and utilizes magnetic flux more efficiently through controlled field weakening. By optimizing the flux component separately from the torque component, it extracts maximum productive work from the limited current supply
4Force
If motor drive current is increased to generate high torque, then torque increases, but electromagnetic force increases and generated sound increases
Solution Approach 1:
The patent changes the parameter of current waveform from simple sinusoidal to vector-controlled with separated components. By controlling the torque and flux components independently, it generates required torque with optimized electromagnetic force, reducing sound generation
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
Suppresses generated sound and stabilizes motor rotation even under load variation, enabling increased discharge amount without enlarging the compressor size.
Implementation Method 1
a motor configured to drive a compression mechanism for compressing air
Data Source
AI summary
An air compressor includes: a motor configured to drive a compression mechanism for compressing air, and a controller configured to control the motor. The motor is an outer rotor motor including a stator and a rotor disposed on an outer side of the stator. The controller is configured to adjust a voltage applied to a stator winding of the stator, based on position information of the rotor.