Powder Feeder Startup Control for Fast Flow Rate Stabilization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional powdery material feeding devices take a long time to stabilize the discharge flow rate after startup, often experiencing hunting phenomena due to inadequate control methods.
Innovation Solution
A powdery material feeding device with a controller that initially conducts constant control of motor speed or voltage for a predetermined period, then shifts to feedback control when the discharge flow rate difference is within a threshold, and reverts to constant control if the difference exceeds the threshold, adjusting the manipulated variable based on the latest control period's ratio to quickly stabilize the supply amount.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback control is used to adjust motor speed at predetermined cycles to correct discharge flow rate differences, then the discharge flow rate can be corrected, but it takes a long time to stabilize and hunting phenomenon occurs
Solution Approach 1:
The controller performs preliminary constant control of the manipulated variable before switching to feedback control. This preliminary action allows the discharge flow rate to stabilize naturally for a predetermined period, preventing hunting phenomenon and reducing overall stabilization time while maintaining accuracy.
2Measurement precision
If feedback control is used to repetitively measure and adjust discharge flow rate, then the target value can be approached, but hunting phenomenon occurs that destabilizes the system
Solution Approach 1:
The controller performs preliminary constant control of the manipulated variable before switching to feedback control. This preliminary action allows the discharge flow rate to stabilize naturally for a predetermined period, preventing hunting phenomenon and reducing overall stabilization time while maintaining accuracy.
3Ease of operation
If constant control is used immediately after motor startup, then the system is simple to operate, but the discharge flow rate takes a long time to stabilize
Solution Approach 1:
The control process is segmented into two distinct phases: initial constant control phase for simplicity and stability, followed by feedback control phase for precision. This segmentation allows the system to benefit from both control methods at appropriate times, reducing overall stabilization time while maintaining ease of operation.
Solution Approach 2:
The controller performs preliminary constant control of the manipulated variable before switching to feedback control. This preliminary action allows the discharge flow rate to stabilize naturally for a predetermined period, preventing hunting phenomenon and reducing overall stabilization time while maintaining accuracy.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A powdery material feeding device includes a controller B05 configured to selectively conduct constantly keeping control of constantly keeping rotational speed of a motor, current or voltage applied to the motor without any change as a manipulated variable for a predetermined period, or feedback control of repetitively obtaining a difference between a discharge flow rate of the powdery material and a target value thereof at predetermined cycles and adjusting by increasing or decreasing the manipulated variable at each of the predetermined cycles in order to reduce the difference, the controller B05 conducts the constantly keeping control immediately after a motor B022 starts, shifts to the feedback control when the difference between the discharge flow rate of the powdery material and the target value thereof has an absolute value less than a threshold after the period for the constantly keeping control elapses, and conducts constantly keeping control without shifting to the feedback control when the absolute value of the difference between the discharge flow rate of the powdery material and the target value thereof is more than the threshold after the period for the constantly keeping control elapses, and the manipulated variable during the repeated constantly keeping control is changed in accordance with the difference between the discharge flow rate of the powdery material and the target value thereof after elapse of the period for latest constantly keeping control.