Compressor Motor Speed Control to Reduce Shutdown Noise
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Solution Overview
Problem
Compressors in climate-control systems produce bothersome noises during shutdown events due to unbalanced rotational forces and pressures, which existing technologies have not effectively mitigated.
Innovation Solution
A control module that adjusts the compressor motor's speed based on actual working fluid pressure and motor speed thresholds to balance forward and backward rotational forces, and holds the compressor in a shutdown state for a predetermined time before restarting, thereby reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the compressor is shut down immediately when a shutdown command is received, then the response time is fast, but noise is generated due to unbalanced rotational forces
Solution Approach 1:
The control module increases the motor's running speed to a predetermined threshold speed before shutting down the compressor. This preliminary speed adjustment ensures that the compression mechanism maintains sufficient rotational momentum to counteract backward rotational forces during shutdown, thereby reducing noise while maintaining fast response time
Solution Approach 2:
The system changes the motor speed parameter dynamically during the shutdown process. By adjusting the motor speed to meet a predetermined threshold before shutdown, the system optimizes the balance between shutdown speed and noise reduction, resolving the contradiction between fast response and noise control
2Object-generated harmful factors
If the motor speed is increased before shutdown, then noise is reduced by balancing rotational forces, but energy consumption increases
Solution Approach 1:
The control module applies partial action by increasing the motor speed only to a predetermined threshold level necessary for noise reduction, rather than maximizing speed. This partial speed increase balances rotational forces sufficiently to reduce noise while minimizing unnecessary energy consumption
Solution Approach 2:
The system uses feedback control to monitor motor speed and working fluid pressure, adjusting the speed increase only as needed to meet the predetermined threshold. This feedback mechanism ensures energy is consumed only when necessary to achieve the noise reduction goal
3Productivity
If the compressor shuts down without holding in shutdown state, then productivity is high, but noise from incomplete motor stoppage occurs
Solution Approach 1:
The control module implements a predetermined shutdown hold time after the shutdown command is received, during which the motor is ensured to complete its stoppage. This preliminary waiting period allows the motor to fully stop before the shutdown is finalized, preventing restart noise while minimizing impact on productivity
Data Source
AI summary
A climate-control system may include a compressor and a control module. The compressor includes a motor driving a compression mechanism to compress a working fluid. The control module is in communication with the motor and may be configured to determine a balance speed of the motor at which a forward-rotational inertial force of the compression mechanism is equal to a backward-rotational gas force on the compression mechanism. The control module may be configured to adjust a running speed of the motor to the balance speed after receipt of a compressor-shutdown-command and before shutting down the compressor.