Startup control systems and methods to reduce flooded startup conditions

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Solution Overview

Problem

Refrigeration systems in vehicles, particularly those using eutectic plates, face increased fault conditions such as flooded startup and liquid floodback due to the enlarged system charge, which can lead to high compressor loads and reduced oil levels, resulting in reliability and lifespan issues.

Innovation Solution

Implementing a variable speed compressor with flooded start logic that predicts flooded startup situations and adjusts operating parameters, including the option for stator heating, to select between normal and flooded startup modes based on conditions like compressor off time and ambient temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the compressor operates in a flooded startup condition, then the compressor can start up, but the high compressor load and reduced oil levels cause reliability and lifespan issues

Engineering Contradiction:

Improvecompressor reliabilityVSAvoidflooded startup condition

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The control module performs preliminary heating of the compressor windings before startup by applying voltage during a heating period. This preliminary action prevents flooded startup conditions by ensuring the compressor is ready to handle liquid refrigerant immediately upon启动, eliminating the harmful effects of flooded conditions before they can damage the compressor.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system applies preliminary anti-action by heating the compressor windings in advance to counteract the potential harmful effects of flooded startup. The heating period is calculated based on the off-time and ambient temperature, creating a protective effect that prevents the high loads and oil level reduction that would otherwise occur during flooded startup.

Inventive Principle:

Principle #9Preliminary anti-action

2Reliability

If the compressor off time is long and ambient temperature is low, then the compressor is more likely to be in a flooded condition, but extending operation to prevent flooded conditions increases energy consumption

Engineering Contradiction:

Improvecompressor reliabilityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The control module dynamically adjusts the heating period parameter based on the compressor off-time and ambient temperature. When off-time is long and temperature is low (high flooded risk), the heating period is extended. When off-time is short or temperature is high (low flooded risk), the heating period is reduced or eliminated. This parameter adaptation optimizes the balance between reliability and energy consumption.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system uses feedback from the off-time sensor and temperature sensor to determine the appropriate heating period. The control module continuously monitors these parameters and adjusts the heating duration accordingly, ensuring energy is consumed only when necessary to prevent flooded conditions.

Inventive Principle:

Principle #23Feedback

3Productivity

If the system uses eutectic plates with enlarged system charge, then the refrigeration capacity is improved, but the fault conditions such as flooded startup and liquid floodback increase

Engineering Contradiction:

Improverefrigeration capacityVSAvoidcompressor reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The control module performs preliminary heating of the compressor before startup by applying voltage during a calculated heating period. This preliminary action prevents flooded startup conditions that are more likely to occur in systems with enlarged refrigerant charge, protecting the compressor from the high loads and oil level reduction that would otherwise result from the increased refrigerant volume.

Inventive Principle:

Principle #10Preliminary action

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 improves the reliability and lifespan of the compressor by reducing the risk of flooded startups and associated loads, allowing for efficient operation and extended component life.

Implementation Method 1

the startup mode control module controls a stator heating control module to provide current to a stator of the motor for a stator heating period, prior to turning on the compressor

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS11660934B2Startup control systems and methods to reduce flooded startup conditions

Publication Date: 2023.05.30 COPELAND LP

AI summary

A control module for a refrigeration system includes a startup mode control module that receives an off time of a compressor and an ambient temperature, determines whether the off time and the ambient temperature indicate that the compressor is in a flooded condition, and selects, based on the determination, between a normal startup mode and a flooded startup mode. A compressor control module transitions from the flooded startup mode to the normal startup mode after a predetermined period associated with operating in the flooded startup mode and operates the compressor at a first speed in the normal startup mode and operates the compressor at a second speed less than the first speed in the flooded startup mode.