Design of a H∞ Robust Controller with μ-Analysis for Steam Turbine Power Generation Applications

Abstract

Concentrated Solar Power plants are complex systems subjected to quite sensitive variations of the steam production profile and external disturbances, thus advanced control techniques that ensure system stability and suitable performance criteria are required. In this work, a multi-objective H ∞ robust controller is designed and applied to the power control of a Concentered Solar Power plant composed by two turbines, a gear and a generator. In order to provide robust performance and stability in presence of disturbances, not modeled plant dynamics and plant-parameter variations, the advanced features of the µ-analysis are exploited. A high order controller is obtained from the process of synthesis that makes the implementation of the controller difficult and computational more demanding for a Programmable Logic Controller. Therefore, the controller order is reduced through the Balanced Truncation method and then discretized. The obtained robust control is compared to the current Proportional Integral Derivative-based governing system in order to evaluate its performance, considering unperturbed as well as perturbed scenarios, taking into account variations of steam conditions, sensor measurement delays and power losses. The simulations results show that the proposed controller achieves better robustness and performance compared to the existing Proportional Integral Derivative controller.

Construction of a method for representing an approximation model of an object as a set of linear differential models

“…In addition, the transfer function of form (18) describes in [15] a steam tract when modeling the boiler control system. In the same way, [16] described a model of the electric hydraulic system with a high-and low-pressure turbine valve when designing a controller for the turbine control system of a steam solar power plant.…”

Control of rotary double inverted pendulum system using mixed sensitivity H∞ controller

“…Nonlinear model of the system in equation (27) can be linearized at the upright position of the pendulums. The dynamics model is rearranged…”

“…To achieve good closed loop performances, such as disturbance rejection, noise attenuation, and control input bandwidth, the mixed sensitivity approach relies on optimization that involves two or more sensitivity functions, the sensitivity function (S), the input sensitivity function (KS), and the complementary sensitivity function (T) as reviewed by Kwakernaak. 18 Thus mixed sensitivity approach can be differed mixed sensitivities, such as S/T in Peng et al 19 and M. Rachedi et al, 20 S/KS in Wei-qian et al, 21 Ozana et al, 22 and Xinping Bao, 23 or S/KS/T in Alfaya et al, 24 Bejarano et al, 25 Delettre et al, 26 Iannino et al, 27 and Fragoso et al 28 Peng et al 19 proposed H∞ controller to solve the S/T problem for the pneumatic manipulator with parameter variation, and low or high frequency disturbances acting on the pneumatic manipulator as uncertainties. Rachedi et al 20 used mixed sensitivity controller for position control of a “Delta” parallel robot.…”

“…Their results showed better tracking performance and robustness against disturbance over PID and model predictive controller. The same controller was applied for a planar manipulator of flexible and contactless handling, steam turbine power generation applications, and a lab-scale wind turbine by Delettre et al, 26 Iannino et al, 27 and Fragoso et al, 28 respectively. Their experiments showed better robust performance over the conventional controllers.…”

Energy Production Systems

“…The adaptation of renewable energy employing concentrated solar power plants is subject to sensitive variations of the steam production profile and external disturbances. The paper by Iannino et al [7] proposes advanced control techniques that ensure system stability and suitable performance criteria. The paper presents the design of a multiobjective H ∞ robust controller and applies it to the power control of a concentrated solar power plant consisting of two turbines, a gear, and a generator.…”