Electric Compressor Motor Control Mode Switching

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The motor of an electric compressor in vehicle air conditioners may unintentionally stop due to high torque load or sudden rotation speed fluctuations, leading to malfunction and potential damage to electronic components.

Innovation Solution

A motor control device with a control unit that switches between two control modes: a precise control mode for high torque and a more efficient mode for wide-range operation, based on rotation speed thresholds and timing, to prevent malfunctions and reduce the risk of electronic component damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the motor control device uses precise control mode to maintain high torque and precise operation, then the motor control precision is improved, but the efficiency and wide-range operation capability deteriorate

Engineering Contradiction:

Improvemotor control precisionVSAvoidcontrol efficiency

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic switching between two control modes (precise control mode and efficient control mode) based on real-time motor operating conditions. The control mode is not fixed but changes dynamically according to the rotation speed threshold, allowing the system to optimize between precision and efficiency at different operating points.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes control parameters by switching between different control modes. The first control mode uses parameters optimized for high torque and precision, while the second control mode uses parameters optimized for efficiency and wide-range operation. This parameter switching allows the system to adapt to different operational requirements.

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If the control mode switches late due to waiting for rotation speed threshold, then the efficiency mode is utilized more, but the motor may malfunction under high torque load or sudden speed fluctuations

Engineering Contradiction:

Improvecontrol efficiencyVSAvoidmotor operation reliability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent performs preliminary switching to the efficient control mode before the motor reaches the rotation speed threshold, based on predicted operating conditions. By switching in advance when certain conditions are met (such as when the required rotation speed indicates upcoming high efficiency operation), the system avoids the risks associated with operating in precise control mode during conditions that would benefit from efficient control mode.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies preliminary anti-action by switching control modes to prevent potential malfunctions before they occur. By monitoring operating conditions and switching to the appropriate control mode in advance, the system prevents spike currents and abnormal operations that could damage electronic components.

Inventive Principle:

Principle #9Preliminary anti-action

3Force

If the motor operates in precise control mode for extended periods, then high torque requirements are met, but spike currents are generated and electronic components may be damaged

Engineering Contradiction:

Improvetorque outputVSAvoidspike current damage

Core Design Contradiction:

ForceVSObject-affected harmful factors

Solution Approach 1:

The patent converts the potential harm of prolonged precise control mode operation into benefit by implementing automatic mode switching. When the motor operates in precise control mode to meet high torque requirements, the system monitors operating conditions and switches to efficient control mode when appropriate, thereby preventing the harmful effects of sustained high-torque operation while still achieving the necessary torque output when needed.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS11418136B2Electric compressor, motor control method, and non-transitory computer-readable medium

Publication Date: 2022.08.16 MITSUBISHI HEAVY IND THERMAL SYST

AI summary

A motor control device provided with a control unit which controls the number of rotations of a motor by implementing a first control which enables high-torque and precise control, or a second control enabling more efficient control than the first control with respect to the motor; and a switching determination unit which, if an actual measurement value of the number of rotations of the motor is greater than a prescribed threshold value of the number of rotations, switches the first control to the second control. The switching determination unit further switches the first control to the second control if the actual measurement value of the number of rotations is not more than the threshold value of the number of rotations, and when a prescribed time has passed from a point in time at which the actual measurement value of the number of rotations matched the required number of rotations.