Method and device for controlling capacity change of compressor, and smart home appliance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Household multi-split air conditioners face inefficiencies due to high energy consumption and unstable system pressure when switching between single-cylinder and double-cylinder compressor modes, leading to reduced operating efficiencies and potential damage.
Innovation Solution
A method and device that determine an intermediate frequency to maintain during capacity changes of the compressor, reducing sudden output changes by selecting a smaller frequency as the intermediate frequency when switching from high to low capacity, and adjusting the operating frequency accordingly to ensure stable system pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the compressor capacity is changed from single-cylinder mode to double-cylinder mode at high frequency, then the cooling or heating capacity is increased, but the system pressure becomes unstable and the compressor may be damaged
Solution Approach 1:
The control method performs preliminary frequency reduction before capacity switching. When switching from single-cylinder to double-cylinder mode, the compressor frequency is first reduced to a predetermined safe level, then the capacity switching is executed. This preliminary action prevents the harmful effect of high-frequency capacity switching while ensuring the switching can be performed safely.
Solution Approach 2:
The method introduces a frequency buffer zone by reducing the operating frequency before capacity switching occurs. This cushioning effect absorbs the mechanical stress and pressure fluctuations that would otherwise occur during abrupt capacity changes at high frequency, protecting the compressor and drive plate from damage.
2Loss of energy
If the compressor operates in low-frequency state under low loads, then the energy consumption is reduced, but the operating efficiency of the motor is reduced
Solution Approach 1:
The system dynamically adjusts the compressor operating mode based on real-time load conditions. When load decreases, the system transitions from double-cylinder mode to single-cylinder mode, and adjusts frequency accordingly. This dynamic adaptation allows the compressor to operate at optimal efficiency points for each operating condition, balancing energy consumption and productivity.
Solution Approach 2:
The control method changes key operating parameters (capacity mode and frequency) based on load conditions. By switching between single-cylinder and double-cylinder modes and adjusting frequency, the system optimizes the balance between energy consumption and operating efficiency for different load scenarios.
3Productivity
If the compressor capacity is suddenly increased from single-cylinder to double-cylinder mode, then the cooling or heating demand is met, but the discharge capacity doubles instantly causing system pressure instability
Solution Approach 1:
Before increasing capacity from single-cylinder to double-cylinder mode, the system first reduces the operating frequency to a predetermined level. This preliminary frequency reduction prepares the system for the upcoming capacity increase, preventing abrupt discharge capacity doubling and the associated pressure instability.
4Temperature
If the compressor is switched off and on repeatedly, then the temperature control is maintained, but temperature fluctuations and energy consumptions increase
Solution Approach 1:
The variable-frequency and variable-capacity technology enables the compressor to continue operating continuously at adjusted parameters (single-cylinder mode with reduced frequency) rather than switching off and on. This continuous operation eliminates the energy waste and temperature fluctuations associated with repeated startup and shutdown cycles.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A method and a device for controlling a capacity change of a compressor, and a smart home appliance. The method includes: determining whether a capacity of the compressor is required to be changed; if yes, determining an intermediate frequency; changing the capacity of the compressor while maintaining the operating frequency of the compressor at the intermediate frequency; wherein the intermediate frequency reduces a sudden change in output of the compressor after the changing the capacity. In the present invention, by determining the intermediate frequency and changing the capacity of the compressor while maintaining the operating frequency of the compressor at the intermediate frequency, the sudden change in output of the compressor after the capacity change is reduced, thereby avoiding the impact on the compressor caused by the sudden increase or sudden decrease of the discharge capacity of the compressor, which improves the stability of the system and guarantees the success of the capacity change.