Refrigeration cycle device, control method, and non-transitory computer-readable storage medium
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Solution Overview
Problem
Conventional refrigeration cycle devices often unnecessarily restrict the performance of inverter motors due to fixed high-pressure limits for refrigerant, leading to inefficient operation.
Innovation Solution
A refrigeration cycle device with a controller that dynamically determines an operating rotation speed for the compressor based on protection and capability target values, using sensors to detect operating states and adjust temperatures and pressures to prevent unnecessary restrictions, incorporating PI or PID controllers to asymptotically control protection variables like discharge temperature, condensation, and evaporation temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed high pressure limit value is used for refrigerant protection, then the refrigeration cycle device is protected under any circumstances, but the inverter motor speed is unnecessarily restricted leading to performance degradation
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed high pressure limit value to a dynamic protection target value that changes based on operating conditions. The controller adjusts the protection target value according to detected operating states (such as ambient temperature, refrigerant temperatures, and pressures), allowing the system to adaptively optimize motor speed while maintaining necessary protection across varying operational scenarios.
2Reliability
If the high pressure limit is set to protect the device under any circumstances, then device protection is ensured, but the motor speed command is overly constrained
Solution Approach 1:
The patent applies parameter changes by modifying the protection target value parameter based on operating conditions. Instead of using a constant high pressure limit, the controller calculates and adjusts the protection target value according to detected parameters such as ambient temperature, refrigerant temperatures, and pressures. This dynamic parameter adjustment maintains device protection while providing flexible motor speed control appropriate to each operating scenario.
Data Source
AI summary
Provided is a refrigeration cycle device including: a refrigeration cycle circuit comprising a compressor configured to compress a refrigerant; an operating state detector configured to detect an operating state of the refrigeration cycle circuit; a protection target value determinator configured to determine, based on the operating state, a protection target value of a protection variable regarding the refrigeration cycle circuit; and a rotation speed determinator configured to determine an operating rotation speed of the compressor, based at least on the protection target value and a capability target value of a temperature adjusted by the refrigeration cycle circuit. Thereby, it is possible to prevent the performance from being unnecessarily restricted.