Model-Based Control of Combustion Instabilities

2005 ◽  
Author(s):  
Aimee S. Morgans ◽  
Ann P. Dowling
Keyword(s):  
Transfer Function ◽  
Controller Design ◽  
Open Loop ◽  
Operating Conditions ◽  
Combustion Instabilities ◽  
Lean Premixed Combustion ◽  
Model Based Control ◽  
Model Based ◽  
Loop Transfer Function ◽  
Mathematical Approximation

Model-based control has been successfully implemented on an atmospheric pressure lean premixed combustion rig. The rig incorporated a pressure transducer in the combustor to provide a sensor measurement, with actuation provided by a fuel valve. Controller design was based on experimental measurement of the open loop transfer function. This was achieved using a valve input signal which was the sum of an identification signal and a control signal from an empirical controller to eliminate the non-linear limit cycle. The transfer function was measured for the main instability occurring at a variety of operating conditions, and was found to be fairly similar in all cases. Using Nyquist and H∞-loop shaping techniques, several robust controllers were designed, based on a mathematical approximation to the measured transfer function. These were implemented experimentally on the rig, and were found to stabilise it under a variety of operating conditions, with a greater reduction in the pressure spectrum than had been achieved by the empirical controller.

scholarly journals Analytical Multiloop Control for Multivariable Systems with Time Delays

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Zhiguo Wang ◽  
Peng Wei
Keyword(s):  
Transfer Function ◽  
Process Model ◽  
Controller Design ◽  
Design Method ◽  
Open Loop ◽  
Multivariable Systems ◽  
Performance Improvements ◽  
Loop Transfer Function ◽  
Multiloop Control ◽  
Multiloop Control System

In this paper, a new design method with performance improvements of multiloop controllers for multivariable systems is proposed. Precise expression is developed to show the relationship between the dynamic- and steady-state characteristics of the multiloop control system and its parameters. First, an equivalent transfer function (ETF) is introduced to decompose the multivariable system, based on which the multiloop controller parameters are calculated. According to the ETF matrix property, an analytical expression for the PI controller for multivariable systems is derived in terms of substituting the ETF matrix for the inverse open-loop transfer function. In the proposed controller design method, no approximation of the inverse of the process model is needed, implying that this method can be applied to some multivariable systems with high dimensions. The simulation results obtained from several examples demonstrate the effectiveness of the proposed method.

scholarly journals On PID Controller Design by Combining Pole Placement Technique with Symmetrical Optimum Criterion

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Viorel Nicolau
Keyword(s):  
Transfer Function ◽  
Closed Loop ◽  
Controller Design ◽  
Open Loop ◽  
Pole Placement ◽  
Loop Transfer Function ◽  
Heading Control ◽  
Pid Controller Design ◽  
Analytical Expressions ◽  
Placement Technique

In this paper, aspects of analytical design of PID controllers are studied, by combining pole placement technique with symmetrical optimum criterion. The proposed method is based on low-order plant model with pure integrator, and it can be used for both fast and slow processes. Starting from the desired closed-loop transfer function, which contains a second-order oscillating system and a lead-lag compensator, it is shown that the zero value depends on the real-pole value of closed-loop transfer function. In addition, there is only one pole value, which satisfies the assumptions of symmetrical optimum criterion imposed to open-loop transfer function. In these conditions, by combining the pole placement technique with symmetrical optimum criterion, the analytical expressions of the controller parameters can be simplified. For simulations, PID autopilot design for heading control problem of a conventional ship is considered.

Study On Automatic Adaptation for Control-Oriented Model of Advanced Diesel Engine

2021 ◽  
Author(s):  
Shunki Nishii ◽  
Yudai Yamasaki
Keyword(s):  
Operating Conditions ◽  
Physical Models ◽  
Model Parameters ◽  
Training Methods ◽  
Model Based Control ◽  
Practical Applications ◽  
Model Based ◽  
Automatic Adaptation ◽  
Automobile Engines ◽  
Adaptation Method

Abstract To achieve high thermal efficiency and low emission in automobile engines, advanced combustion technologies using compression autoignition of premixtures have been studied, and model-based control has attracted attention for their practical applications. Although simplified physical models have been developed for model-based control, appropriate values for their model parameters vary depending on the operating conditions, the engine driving environment, and the engine aging. Herein, we studied an onboard adaptation method of model parameters in a heat release rate (HRR) model. This method adapts the model parameters using neural networks (NNs) considering the operating conditions and can respond to the driving environment and the engine aging by training the NNs onboard. Detailed studies were conducted regarding the training methods. Furthermore, the effectiveness of this adaptation method was confirmed by evaluating the prediction accuracy of the HRR model and model-based control experiments.

scholarly journals Measurement of Air-Fuel Ratio Fluctuations Caused by Combustor Driven Oscillations

1998 ◽  
Author(s):  
Rajiv Mongia ◽  
Robert Dibble ◽  
Jeff Lovett
Keyword(s):  
Power Spectrum ◽  
Mole Fraction ◽  
Gas Turbines ◽  
Operating Conditions ◽  
Premixed Combustion ◽  
Pollutant Emissions ◽  
Combustion Instabilities ◽  
Pressure Oscillations ◽  
Lean Premixed Combustion ◽  
Lean Premixed

Lean premixed combustion has emerged as a method of achieving low pollutant emissions from gas turbines. A common problem of lean premixed combustion is combustion instability. As conditions inside lean premixed combustors approach the lean flammability limit, large pressure variations are encountered. As a consequence, certain desirable gas turbine operating regimes are not approachable. In minimizing these regimes, combustor designers must rely upon trial and error because combustion instabilities are not well understood (and thus difficult to model). When they occur, pressure oscillations in the combustor can induce fluctuations in fuel mole fraction that can augment the pressure oscillations (undesirable) or dampen the pressure oscillations (desirable). In this paper, we demonstrate a method for measuring the fuel mole fraction oscillations which occur in the premixing section during combustion instabilities produced in the combustor that is downstream of the premixer. The fuel mole fraction in the premixer is measured with kHz resolution by the absorption of light from a 3.39 μm He-Ne laser. A sudden expansion combustor is constructed to demonstrate this fuel mole fraction measurement technique. Under several operating conditions, we measure significant fuel mole fraction fluctuations that are caused by pressure oscillations in the combustion chamber. Since the fuel mole fraction is sampled continuously, a power spectrum is easily generated. The fuel mole fraction power spectrum clearly indicates fuel mole fraction fluctuation frequencies are the same as the pressure fluctuation frequencies under some operating conditions.

Robust Feedback Control of a Baffled Plate via Open-Loop Optimization

2001 ◽  
Vol 124 (1) ◽  
pp. 154-157 ◽  
Author(s):  
P. De Man ◽  
A. Franc¸ois ◽  
A. Preumont
Keyword(s):  
Genetic Algorithm ◽  
Control System ◽  
Transfer Function ◽  
Open Loop ◽  
Displacement Sensor ◽  
Search Procedure ◽  
Loop Optimization ◽  
Loop Transfer Function ◽  
Poles And Zeros ◽  
Siso System

A SISO control system is built by using a volume displacement sensor and a set of actuators driven in parallel with a single amplifier. The actuators location is optimized to achieve an open-loop transfer function which exhibits alternating poles and zeros, as for systems with collocated actuators and sensors; the search procedure uses a genetic algorithm. The ability of a simple lead compensator to control this SISO system is numerically demonstrated.

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