Inverter Compressor Control for Stable Indoor Temperature
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Solution Overview
Problem
Air-conditioning systems in North America, controlled by local thermostats, lead to frequent compressor activation and deactivation, resulting in increased power consumption and difficulty in maintaining a constant indoor temperature, degrading comfort.
Innovation Solution
An air-conditioning system with a refrigerant circuit, an inverter-driven compressor, and a controller that adjusts the inverter output frequency based on thermostat signals to maintain a predetermined temperature difference, reducing power consumption and maintaining a constant indoor temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the local thermostat frequently transmits on/off signals to control the compressor, then the target temperature control is achieved, but the compressor is repeatedly activated and stopped leading to increased power consumption
Solution Approach 1:
The patent applies periodic action by using a timer to control the intermittent operation of the compressor. The timer generates periodic on/off signals that activate the compressor for predetermined time intervals, then deactivate it. This periodic operation pattern reduces the frequency of compressor activation compared to continuous thermostat control, thereby lowering power consumption while still achieving temperature control through cumulative cooling effect over time.
Solution Approach 2:
The patent implements preliminary action by pre-determining the operation timing and duration of the compressor through a timer before actual temperature control is needed. The timer is programmed in advance with optimal operating cycles, allowing the system to execute predetermined operation patterns that have been optimized to reduce power consumption while maintaining effective temperature regulation.
2Temperature
If the compressor is repeatedly activated and stopped to follow thermostat signals, then the target temperature is approached, but the indoor temperature cannot be maintained at a constant level degrading comfort
Solution Approach 1:
The periodic action principle maintains temperature stability by using the timer to create regular, predictable compressor operation cycles. Instead of abrupt on/off switching that causes temperature fluctuations, the timer sustains compressor operation for optimized time intervals, allowing the system to maintain a more stable indoor temperature through consistent periodic cooling rather than intermittent operation.
Solution Approach 2:
The patent applies continuity of useful action by extending the compressor operation duration through timer control. Rather than allowing the compressor to stop frequently in response to brief thermostat signals, the timer maintains continuous or near-continuous compressor operation for predetermined intervals, ensuring uninterrupted cooling action that keeps the indoor temperature stable and comfortable throughout the operation cycle.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
Provided is an air-conditioning system (100) capable of suppressing power consumption and maintaining the indoor temperature at a constant level. The air-conditioning system includes a refrigerant circuit in which a compressor (5), a heat source-side heat exchanger (6), an expansion device (11), and a load-side heat exchanger (10) are sequentially connected via a pipe, an inverter (16) that drives the compressor (5), an indoor temperature sensor (14) that detects an indoor temperature, and a controller (13) that receives a thermostat ON signal and a thermostat OFF signal and controls the inverter (16) according to the thermostat ON signal and the thermostat OFF signal. The controller (13) assumes, upon receipt of the thermostat OFF signal, that the indoor temperature detected at that time is a target temperature, and regulates an output frequency of the inverter (16) so as to maintain a difference between the indoor temperature and the target temperature in a predetermined range.