Motor Driven Compressor Rotor Reverse Rotation Control
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Solution Overview
Problem
Conventional motor-driven compressors face difficulties in smooth restart due to residual intermediate pressure refrigerant causing reverse rotation of the rotor, which hinders immediate restart of the rotation control.
Innovation Solution
A motor-driven compressor system with a controller that outputs a stop instruction to deactivate rotor rotation, determines the rotor's condition using a voltage detector, and performs restart preparation control by outputting a lock instruction to electrically stop the rotor, allowing for smooth restart by managing switching operations in the motor drive circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor-driven compressor stops operation by deactivating rotation control, then the rotor gradually stops forward rotation, but residual refrigerant causes reverse rotation that prevents immediate restart
Solution Approach 1:
The control circuit performs preliminary action by detecting reverse rotation of the rotor through voltage detection and actively counteracting it with electromagnetic braking force before restart is attempted. This prevents the harmful reverse rotation state from persisting, enabling immediate restart without waiting for natural deceleration.
2Ease of operation
If residual intermediate pressure gaseous refrigerant is drawn into the compression chamber, then the movable scroll orbits in reverse direction, but this reverse orbiting rotates the rotor backward exceeding restart threshold
Solution Approach 1:
The control circuit implements feedback by continuously monitoring the rotor's rotation state through voltage detection and dynamically adjusting the electromagnetic braking force. The control circuit detects reverse rotation voltage signals and responds by applying counteracting electromagnetic force, creating a closed-loop control system that automatically manages reverse rotation without complex mechanical mechanisms.
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
Enables quick and smooth restart of the motor-driven compressor by effectively managing the rotor's rotation and eliminating reverse rotation, improving the compressor's operational reliability.
Implementation Method 1
a voltage detector that detects a terminal voltage of the electric motor
Implementation Method 2
an electric motor that includes a rotor and drives the compression unit
Data Source
AI summary
A motor-driven compressor includes a compression unit that includes movable and fixed scrolls and a compression chamber, an electric motor that includes a rotor and drives the compression unit, a motor drive circuit that drives the electric motor, an injection port that draws intermediate pressure refrigerant into the compression chamber, a controller that performs rotation control on the rotor, and a voltage detector that detects a terminal voltage of the electric motor. The compression unit compresses low pressure refrigerant drawn into the compression chamber to discharge high pressure refrigerant. The controller is configured to output a stop instruction to deactivate the rotation control of the rotor, determine a rotation condition of the rotor based on the voltage detected by the voltage detector after outputting the stop instruction, and perform, based on the determination, restart preparation control that includes outputting a lock instruction to electrically stop rotation of the rotor.