Linkage control method and apparatus for indoor and outdoor units of precision air conditioner

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Solution Overview

Problem

The existing precision air conditioner systems have slow adjustment and control speed, high delay, and do not optimize the coefficient of performance (COP) due to separate control of evaporator and condenser, ignoring their correlation.

Innovation Solution

A linkage control method and apparatus that optimizes the rotational speeds of indoor and outdoor fans by using a PID algorithm to obtain target working frequencies and temperatures, maximizing the COP by adjusting the compressor, condenser, and evaporator settings based on temperature and pressure differences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If separate control of evaporator and condenser is used, then control simplicity is maintained, but coefficient of performance optimization is lost and control delay increases

Engineering Contradiction:
Improvecontrol system complexityVSAvoidcoefficient of performance
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent merges the separate control systems of the evaporator and condenser into a unified linkage control system. The control device receives temperature and pressure parameters from both units and performs coordinated control based on their coupling relationship, thereby optimizing the overall coefficient of performance while maintaining manageable control complexity through integrated algorithmic processing.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements feedback mechanisms by continuously monitoring temperature parameters from the evaporator and pressure parameters from the condenser. These feedback signals are processed by the control device to dynamically adjust control outputs, enabling real-time optimization of the coupling relationship between evaporator and condenser operations.

Inventive Principle:
Principle #23Feedback

2Device complexity

If separate control of evaporator and condenser is used, then control simplicity is maintained, but control speed is slow and delay is high

Engineering Contradiction:
Improvecontrol system complexityVSAvoidcontrol speed
Core Design Contradiction:
Device complexityVSSpeed

Solution Approach 1:

The patent merges the separate control systems of the evaporator and condenser into a unified linkage control system. The control device receives temperature and pressure parameters from both units and performs coordinated control based on their coupling relationship, thereby optimizing the overall coefficient of performance while maintaining manageable control complexity through integrated algorithmic processing.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The control device performs preliminary calculations to determine target working frequencies for both the evaporator and condenser based on their coupling relationship. By pre-computing optimal control parameters and issuing coordinated control outputs simultaneously, the system reduces control delay and improves response speed compared to sequential separate control.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If fan rotational speeds are adjusted to match heat exchange capacity, then heat exchange efficiency is improved, but energy consumption increases

Engineering Contradiction:
Improveheat exchange capacityVSAvoidfan energy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent dynamically adjusts fan rotational speed parameters based on real-time temperature and pressure measurements from the evaporator and condenser. By continuously optimizing the rotational speed to match actual heat exchange capacity requirements rather than operating at fixed high speeds, the system maintains high heat exchange efficiency while minimizing unnecessary fan energy consumption.

Inventive Principle:
Principle #35Parameter changes

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 fast adjustment and control with low delay, optimizing the overall coefficient of performance of the air conditioner system by synchronizing fan rotational speeds with heat exchange capacity requirements.

Implementation Method 1

the compressor compresses a gaseous refrigerant into a high-temperature and high-pressure state

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

a function of the fans is to enhance a heat exchange effect by means of forced convection

Methodology Applied
Scientific EffectForced convection: Forced Convection

Implementation Method 3

The liquid refrigerant flows through a throttle mechanism (the expansion valve) and changes into a low-pressure and low-temperature gas-liquid mixed state

Methodology Applied
Scientific EffectThrottling: Pressure Drop

Implementation Method 4

The gas-liquid two-phase refrigerant is evaporated in the evaporator, and during a phase change from liquid to gas, the refrigerant absorbs a large amount of heat

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3228958B1Linkage control method and apparatus for indoor and outdoor units of precision air conditioner
Publication Date: 2021.05.19 HUAWEI DIGITAL POWER TECH CO LTD
  • EP3228958B1 patent drawingFigure 1
  • EP3228958B1 patent drawingFigure 2
  • EP3228958B1 patent drawingFigure 3

AI summary

The present invention provides a linkage control method for indoor and outdoor units of a precision air conditioner, including: obtaining a target cooling capacity Qn of a compressor, a target power W1 of the compressor, a target power W2 of a condenser, and a target power W3 of an evaporator; optimizing, in a range of Qn(±a%+1), a target working frequency fn, a condensing temperature Tcn, and an evaporating temperature Tcn respectively in specified ranges according to a coefficient of performance (COP) function of the air conditioner, so as to obtain a target working frequency fnd, a target condensing temperature Tcnd, and a target evaporating temperature Tend when a COP value is maximum, where a is a preset natural number; and adjusting a rotational speed N of the evaporator according to a target temperature difference between an inlet and an outlet of the evaporator, controlling the compressor to run at the target working frequency fnd, and adjusting a rotational speed M of the condenser according to the target condensing temperature Tcnd of the condenser, where the target temperature difference between the inlet and the outlet of the evaporator is Δt2-(Tend-Ten).