Photovoltaic Air Conditioner Frequency Control for Inverter Heat Limits

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Solution Overview

Problem

Current air conditioner control methods are not applicable to photovoltaic air conditioners, leading to equipment damage and affecting heating or cooling efficiency due to inadequate frequency limitation and reduction control.

Innovation Solution

A photovoltaic air conditioner control method that detects grid-side inverter module temperature and current in real-time, determining specific intervals to perform frequency limitation and reduction control, preventing compressor damage and optimizing power generation efficiency by setting and resetting flag bits for corresponding control strategies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If frequency limitation and reduction control is not implemented, then power generation efficiency is maximized, but compressor damage occurs due to excessive frequency

Engineering Contradiction:
Improvepower generation efficiencyVSAvoidcompressor safety
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements dynamic frequency control by detecting inverter module temperature and adjusting the compressor frequency accordingly. When temperature exceeds thresholds, the system changes the operating parameter (frequency) from high to limited/reduced levels, preventing compressor damage while maximizing power generation during normal operation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system continuously detects inverter module temperature and uses this feedback to adjust compressor frequency. The control method establishes a feedback loop where temperature measurements trigger frequency limitation or reduction actions, ensuring compressor protection while maintaining optimal power generation efficiency

Inventive Principle:
Principle #23Feedback

2Reliability

If frequent frequency adjustments are made to protect the compressor, then compressor safety is improved, but heating or cooling efficiency deteriorates

Engineering Contradiction:
Improvecompressor safetyVSAvoidheating or cooling efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent divides the temperature range into multiple threshold levels (first threshold, second threshold, third threshold) with corresponding control strategies. This segmentation allows the system to apply frequency limitation only when necessary, avoiding unnecessary adjustments that would reduce heating or cooling efficiency while still protecting the compressor

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control method applies frequency limitation or reduction only when temperature exceeds specific thresholds, rather than continuously adjusting frequency. This partial action approach protects the compressor from damage while minimizing the impact on heating or cooling efficiency during normal operating conditions

Inventive Principle:
Principle #16Partial or excessive action

3Ease of operation

If traditional air conditioner control methods are used, then equipment operation is simplified, but they are not applicable to photovoltaic air conditioners leading to equipment damage

Engineering Contradiction:
Improvecontrol simplicityVSAvoidequipment compatibility
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent develops a control method that adapts traditional air conditioner frequency control principles to photovoltaic air conditioner systems. The method monitors inverter module temperature (specific to photovoltaic systems) and applies frequency limitation/reduction control, making the control strategy universally applicable to both traditional and photovoltaic air conditioners while ensuring equipment safety

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

The method effectively limits and reduces compressor frequency to prevent damage and maintain efficient heating or cooling, increasing power generation efficiency while avoiding repeated frequency adjustments that could affect performance.

Implementation Method 1

a photovoltaic air conditioner is a combination of an inverter and an air conditioner... When the power generation at the photovoltaic side of the photovoltaic air conditioner exceeds the tolerance range

Methodology Applied
Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentEP3967946B1Photovoltaic air conditioner control method and apparatus and photovoltaic air conditioner
Publication Date: 2023.08.16 GREE ELECTRIC APPLIANCE INC OF ZHUHAI
  • EP3967946B1 patent drawingFigure 1~3
  • EP3967946B1 patent drawingFigure 4
  • EP3967946B1 patent drawingFigure 5

AI summary

A photovoltaic air conditioner control method and apparatus and a photovoltaic air conditioner. The method comprises: detecting in real time the grid-connected side inverter module temperature and the grid-connected side current of a photovoltaic air conditioner; determining the interval in which the grid-connected inverter module temperature is located and the interval in which the grid-connected side current is located; and, on the basis of the determining results, performing frequency-limiting and frequency-reduction control of the photovoltaic air conditioner. By means of the present method, rapid frequency limiting and reduction can be implemented without the need to detect the operating frequency of the compressor, preventing the equipment from being damaged due to the continuous increase of the operating frequency of the compressor when the power of the photovoltaic side power generation is high, and also avoiding repeated frequency limiting and reduction of the compressor affecting the current heating or cooling effect of the photovoltaic air conditioner.