Oscillation Detection in Control Loops using PRONY Analysis

Oscillations in process control loops present a serious threat to normal functioning of plant as they lead to product quality variations, fast wear and tear of plant components, possible loss of human lives and property. As a result, overall profitability of the plant gets compromised. To cater to these issues automatic detection of plant wide control loop oscillations is a top most priority for control engineers and industrial consultants. In this work a new automatic oscillation detection algorithm has been proposed based on Prony method for time domain design of infinite impulse response (IIR) filter. In this method IIR filter is designed with time domain impulse response same as the input data. Further, oscillations in the control loop were detected based on the location of IIR filter poles on z-plane. Performance of the proposed algorithm was evaluated for oscillation detection for simulated data, real plant data and industrial plant data. Proposed algorithm was successfully able to detect oscillations in all the cases.