Motor-Driven Compressor Reverse Rotation Control
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Solution Overview
Problem
Motor-driven compressors experience reverse rotation recurrence actions, leading to increased noise and vibration when intermediate pressure fluid remains in the injection pipe after deactivation, interfering with the compressor's activation.
Innovation Solution
A motor-driven compressor with a controller that performs deceleration and continuation controls to manage the rotor's rotational frequency, ensuring the rotor is decelerated to a target frequency during the first period and maintained at a lower frequency during a second period longer than the first, effectively discharging intermediate pressure fluid and reducing noise and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the rotor is rapidly stopped by forcible deactivation control, then the reverse rotation is stopped quickly, but the intermediate pressure fluid remains in the injection pipe causing reverse rotation recurrence
Solution Approach 1:
The controller performs a preliminary deceleration control phase before the forcible stop, gradually reducing the rotor's rotational frequency. This preliminary action allows the intermediate pressure fluid to be discharged in advance, preventing it from causing reverse rotation recurrence after the rotor stops.
Solution Approach 2:
The controller maintains the rotor's rotation continuously during the deceleration control phase rather than immediately stopping it. This continuous rotation ensures that the intermediate pressure fluid continues to flow out through the injection pipe, preventing fluid accumulation that would cause reverse rotation recurrence.
2Productivity
If the rotor rotates at high rotational frequency during reverse rotation, then the reverse rotation action is strong, but noise and vibration increase
Solution Approach 1:
The controller changes the rotational frequency parameter of the rotor during deceleration control, reducing it from the high frequency that causes noise and vibration to a lower frequency that minimizes these harmful effects while still maintaining enough rotation to discharge the intermediate pressure fluid.
3Reliability
If the rotor is stopped completely, then the reverse rotation recurrence may occur, but if the rotor continues to rotate, then noise and vibration persist
Solution Approach 1:
The controller performs preliminary deceleration control to discharge the intermediate pressure fluid before the rotor comes to a complete stop. This preliminary action prevents reverse rotation recurrence while minimizing the duration of rotor rotation, thereby reducing noise and vibration.
Solution Approach 2:
The controller allows the rotor to continue rotating at a reduced frequency for a longer duration than strictly necessary to stop reverse rotation, ensuring complete discharge of the intermediate pressure fluid. This partial excessive action prevents reverse rotation recurrence while keeping noise and vibration at acceptable levels.
Data Source
AI summary
A motor-driven compressor includes an electric motor including a rotor, a housing, a compression unit, a drive circuit, and a controller. The controller includes a deceleration controller that performs a deceleration control, which decelerates the rotor, during a first period in response to the rotor being rotating in a direction opposite to the forward direction, and a continuation controller that performs a continuation control, which continues the rotation of the rotor, during a second period that is longer than the first period after the deceleration control is performed. A fluctuation difference of a rotational frequency of the rotor during the continuation control is less than a deceleration rotational frequency difference.