Motor-Driven Compressor Reverse Rotation Deceleration Control
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Solution Overview
Problem
Motor-driven compressors experience delayed activation due to reverse rotation of the rotor, which increases the time required to start and reduces responsiveness when residual intermediate-pressure fluid enters the compression chamber upon shutdown.
Innovation Solution
A motor-driven compressor with a controller that executes deceleration control by decreasing the current frequency to the d-axis of the rotor when reverse rotation occurs, allowing for quick activation by controlling the inverter to manage the phase currents and rotation speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor-driven compressor stops operating and residual intermediate-pressure fluid enters the compression chamber, then the movable scroll orbits in reverse direction, but the activation time increases and responsiveness decreases
Solution Approach 1:
The controller detects reverse rotation of the rotor and executes deceleration control before normal operation can commence, actively preventing the harmful effect rather than waiting for it to occur naturally. This preliminary intervention reduces the reverse rotation duration and enables faster activation.
Solution Approach 2:
The controller changes the electrical parameters (current frequency and phase) supplied to the motor to execute deceleration control. By adjusting the frequency and phase of the current flowing to the d-axis of the rotor, the system actively controls the reverse rotation deceleration, transforming the passive waiting period into an actively managed process that reduces activation time.
2Loss of time
If deceleration control is executed by controlling current frequency to the d-axis of the rotor, then the reverse rotation is reduced and activation time decreases, but the device complexity increases due to additional control mechanisms
Solution Approach 1:
The controller performs multiple functions: it detects the rotation direction of the rotor, determines when reverse rotation occurs, executes deceleration control by adjusting current parameters, and manages normal operation. By consolidating these functions into a single control unit, the patent avoids adding separate mechanical devices while achieving active reverse rotation management.
Solution Approach 2:
The patent replaces potential mechanical solutions (such as mechanical brakes or clutch mechanisms) with an electrical control system that manages reverse rotation through current frequency and phase adjustment. This substitution maintains simplicity by using the existing motor control infrastructure rather than introducing separate mechanical deceleration devices.
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 solution enables the motor-driven compressor to be quickly activated even when the rotor is rotating in reverse, reducing startup delays and maintaining responsiveness by efficiently managing the rotor's rotation speed and torque.
Implementation Method 1
a motor including a rotor... the controller executes a deceleration control that controls the drive circuit so that current flows to the d-axis of the rotor
Implementation Method 2
a compression unit that compresses the low-pressure fluid and discharges compressed high-pressure fluid... The compression unit compresses the low-pressure fluid drawn into the compression chamber when the rotor rotates
Data Source
AI summary
A motor-driven compressor is provided with a motor including a rotor, a housing including an inlet through which low-pressure refrigerant serving as a low-pressure fluid is drawn in, a compression unit that compresses the low-pressure refrigerant and discharges compressed high-pressure fluid, an inverter that drives the motor, and a controller that controls the inverter. If the rotor is activating in a reverse direction that is opposite to a forward direction when activating the motor, the controller obtains a position of a d-axis of the rotor and controls the inverter so that current flows to the obtained d-axis and so that frequency of current flowing to the motor decreases as time elapses.