Air Conditioner Compressor Connection Switching During Defrosting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing air-conditioning apparatuses face challenges in maintaining energy efficiency in low-load regions and high capacity in high-load regions while ensuring user comfort, as current connection switching methods require compressor shutdowns, impairing comfort functions.
Innovation Solution
An air-conditioning apparatus with a connection switching device that synchronizes the switching of stator windings between delta and star connections with defrosting operations, allowing for efficient energy use without increasing compressor stop frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If connection switching is performed by stopping compressor operation, then switching safety is improved, but user comfort deteriorates due to increased compressor stop frequency
Solution Approach 1:
The system performs connection switching during defrosting operations, which are predetermined maintenance intervals where the compressor is already stopped. By preparing and executing switching actions during these pre-scheduled stop periods, the system avoids additional stops solely for switching purposes, thereby maintaining user comfort while ensuring safe switching conditions.
Solution Approach 2:
The control device automatically determines optimal switching timing by monitoring defrosting operation status and compressor state. The system self-manages the switching process without requiring manual intervention or additional user-aware stops, using the existing operational patterns of the air conditioner to its advantage.
2Use of energy by moving object
If stator windings are connected in star configuration, then energy efficiency in low-load region is improved, but high-speed operation capability deteriorates due to induced voltage limits
Solution Approach 1:
The system dynamically switches between star and delta connections based on real-time operational conditions, specifically during defrosting cycles. This dynamic reconfiguration allows the motor to adapt its electrical characteristics to match varying speed requirements, optimizing both energy efficiency at low speeds and high-speed capability when needed.
Solution Approach 2:
The invention changes the electrical connection parameter of the stator windings from fixed to variable. By altering the connection configuration (star/delta) based on operational phase, the system modifies key electrical parameters such as induced voltage and current characteristics to suit different operational requirements.
3Speed
If stator windings are connected in delta configuration, then high-speed operation capability is improved, but energy efficiency in low-load region deteriorates due to increased current and inverter losses
Solution Approach 1:
The system employs dynamic connection switching that adapts the stator winding configuration to operational demands. During defrosting operations, the system transitions to star connection to minimize energy losses, while maintaining delta connection capability for high-speed operations when energy efficiency is less critical.
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 enables energy efficiency in low-load regions and high capacity in high-load regions without compromising user comfort by minimizing compressor stops and optimizing power consumption.
Implementation Method 1
a connection switching device configured to switch connection of stator windings of the electric motor between a first connection state and a second connection state higher in line-to-line voltage than the first connection state
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An air-conditioning apparatus includes a refrigerant circuit including a compressor, an indoor-side heat exchanger, and an outdoor-side heat exchanger; a drive circuit configured to drive an electric motor; a connection switching device configured to switch connection of stator windings of the electric motor between a first connection state and a second connection state higher in line-to-line voltage than the first connection state; and a controller configured to perform defrosting operation for removing frost formed on the outdoor-side heat exchanger and cause the connection switching device to switch connection. In performing the defrosting operation with the stator windings being in the second connection state, the controller causes the connection switching device to switch the connection of the stator windings from the second connection state to the first connection state.