Compressor Piston Parking Position Control via Motor Current Feedback

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Solution Overview

Problem

Determining the optimal parking position for compressor pistons in refrigeration systems is challenging, leading to refrigerant backflow when the motor is turned off, resulting in energy consumption and inefficient cooling.

Innovation Solution

A method involving current value evaluations during motor operation to measure and compare motor current values, peak motor current values, and phase angles to determine and update the optimal parking position, ensuring accurate positioning of the piston for minimal fluid communication between passages and the chamber.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the motor is turned off without accurate piston position determination, then energy consumption is reduced, but refrigerant backflow occurs causing energy loss and inefficient cooling

Engineering Contradiction:

Improvemotor energy consumptionVSAvoidrefrigerant backflow energy loss

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The system continuously monitors motor current values during operation and uses this feedback to determine when the piston reaches optimal parking position. The controller compares real-time current values against threshold values to accurately detect piston position, enabling precise motor shutdown timing that prevents refrigerant backflow while minimizing energy consumption.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces mechanical position sensing mechanisms with an electrical measurement approach. By monitoring motor current characteristics and comparing them against predetermined thresholds, the system determines piston position electrically rather than using complex mechanical sensors or switches, simplifying the system while achieving accurate position detection.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If the piston is positioned at optimal parking position, then refrigerant backflow is prevented, but determination of optimal position is difficult and frequently inaccurate

Engineering Contradiction:

Improverefrigerant backflow preventionVSAvoidpiston position determination accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system uses continuous feedback from motor current measurements to determine piston position. By monitoring the electrical characteristics of the motor during operation and comparing them against predetermined thresholds, the system accurately detects when the piston reaches the optimal parking position, eliminating the need for complex mechanical position sensing.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The motor itself provides the information needed for position detection through its current consumption characteristics. The system leverages the motor's own electrical behavior during operation to determine piston position, eliminating the need for separate sensing mechanisms and simplifying the overall system while improving reliability.

Inventive Principle:

Principle #25Self-service

3Measurement precision

If real-time updates of optimal parking position are implemented, then positioning accuracy is improved, but system complexity increases

Engineering Contradiction:

Improveoptimal parking position determination accuracyVSAvoidcontrol system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical position sensing and update mechanisms with simple electrical current monitoring. The controller uses predetermined current threshold values to detect piston position in real-time, achieving accurate position determination without adding mechanical complexity to the system.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system monitors changes in motor current parameters during operation to determine piston position. By tracking variations in electrical current characteristics and comparing them against predetermined thresholds, the system achieves real-time position updates through simple electrical measurements rather than complex mechanical sensing.

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 allows for real-time updates and accurate determination of the optimal parking position, reducing refrigerant backflow and energy loss by ensuring the piston is correctly positioned when the motor is turned off, enhancing the efficiency of the refrigeration cycle.

Implementation Method 1

measuring a motor current value at the time and comparing the motor current value to an existing optimal parking current value

Methodology Applied

Scientific EffectElectrical current measurement: Ohmmeter

Data Source

PatentUS9470225B2Compressors and methods for determining optimal parking positions for compressor pistons

Publication Date: 2016.10.18 HAIER US APPLIANCE SOLUTIONS INC

AI summary

Compressors and methods for determining optimal parking positions for compressor pistons are provided. A method includes performing a current value evaluation for an initial time during operation of a motor of the compressor. Performing the current value evaluation includes measuring a motor current value at the time and comparing the motor current value to an existing optimal parking current value. Performing the current value evaluation further includes modifying the existing optimal parking current value to the motor current value when the motor current value exceeds or is equal to the existing optimal parking current value.