Compressor Flux-Weakening Control Using Voltage Threshold Delay
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Solution Overview
Problem
Permanent magnet synchronous compressors easily enter a field weakening control area during high-speed operation, leading to reduced efficiency and system instability due to changes in Id current, which affects position estimation and overall system stability.
Innovation Solution
A device and method for field weakening control that sets a rotational speed threshold for the compressor, preventing temporary entry into field weakening control and allowing the output voltage to rise when the compressor's rotational speed exceeds this threshold, delaying the entry into field weakening control until the voltage can no longer increase, thereby improving efficiency and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the compressor operates in high-speed area, then the rotational speed increases, but the compressor easily enters field weakening control area causing efficiency reduction and system instability
Solution Approach 1:
The control method performs preliminary detection of rotational speed and proactively adjusts the output voltage before the compressor enters the field weakening control area. By detecting when the rotational speed approaches the field weakening threshold and preemptively adjusting the voltage, the system prevents the undesirable Id current increase and position estimation errors from occurring in the first place.
Solution Approach 2:
The control apparatus continuously monitors the rotational speed of the compressor and uses this feedback to dynamically adjust the output voltage of the main circuit unit. When the rotational speed reaches a threshold indicating proximity to field weakening control, the feedback mechanism triggers voltage adjustment to maintain optimal operating conditions and prevent system instability.
2Speed
If the compressor enters field weakening control, then the rotational speed can be maintained, but the efficiency of the whole machine becomes lower
Solution Approach 1:
The control method performs preliminary detection of rotational speed and proactively adjusts the output voltage before the compressor enters the field weakening control area. By detecting when the rotational speed approaches the field weakening threshold and preemptively adjusting the voltage, the system prevents the undesirable Id current increase and position estimation errors from occurring in the first place.
Solution Approach 2:
The control apparatus changes the output voltage parameter in response to rotational speed changes. When the compressor approaches field weakening conditions, the system adjusts the voltage parameter to optimize the balance between maintaining rotational speed and preserving machine efficiency, thereby reducing energy losses associated with field weakening operation.
3Speed
If the Id current increases during field weakening control, then the rotational speed can be controlled, but position estimation becomes inaccurate and system stability deteriorates
Solution Approach 1:
The control method performs preliminary detection of rotational speed and proactively adjusts the output voltage before the compressor enters the field weakening control area. By detecting when the rotational speed approaches the field weakening threshold and preemptively adjusting the voltage, the system prevents the undesirable Id current increase and position estimation errors from occurring in the first place.
Solution Approach 2:
The control apparatus continuously monitors the rotational speed of the compressor and uses this feedback to dynamically adjust the output voltage of the main circuit unit. When the rotational speed reaches a threshold indicating proximity to field weakening control, the feedback mechanism triggers voltage adjustment to maintain optimal operating conditions and prevent system instability.
Data Source
Figure 1~2
AI summary
The present disclosure relates to the field of compressor control, and discloses a device for field weakening control of a compressor. The device includes a main circuit unit and the compressor, wherein the main circuit unit provides power for the compressor, and the device further includes: a compressor rotational speed obtaining unit; and a control unit used to compare the rotational speed ω of the compressor with a rotational speed threshold ω1 of the compressor, and control the main circuit unit as follows according to comparison results: when the rotational speed ω of the compressor is less than ω1, an output voltage of the main circuit unit is controlled at a fixed value V0; and when the rotational speed ω of the compressor is greater than or equal to ω1, the compressor is controlled not to enter the field weakening control temporarily and the output voltage of the main circuit unit is controlled to rise, and the compressor is controlled to enter the field weakening control when the output voltage of the main circuit unit cannot continue to rise. In this way, the time for the compressor to enter the field weakening control can be delayed to the greatest extent, the compressor is controlled not to enter the field weakening control to the greatest extent, and the stability of the system is improved. The present disclosure further discloses a method for field weakening control of a compressor, a storage medium and an air conditioner.