Showing papers on "Closed-loop pole published in 2016"

Design of Observer-Based Robust Power System Stabilizers

Abstract: Power systems are subject to undesirable small oscillations that might grow to cause system shutdown and consequently great loss of national economy. A model to describe power system dynamics for different loads is derived in the norm-bounded form. The first controller design is based on the derived model to achieve robust stability against load variation. The design is based on a new Bilinear matrix inequality (BMI) condition. The BMI optimization is solved interatively in terms of Linear Matrix Inequality (LMI) framework. The condition contains a symmetric positive definite full matrix to be obtained, rather than the commonly used block diagonal form. The difficulty in finding a feasible solution is thus alleviated. The resulting LMI is of small size, easy to solve. The second PSS design shifts the closed loop poles in a desired region so as to achieve a favorite settling time and damping ratio via a non-iterative solution to a set of LMIs. Simulation results based on single-machine and multi-machine power system models verify the ability of the proposed PSS to satisfy control objectives for a wide range of load conditions.

Design of Observer-Based Robust Power System Stabilizers

Abstract: Power systems are subject to undesirable small oscillations that might grow to cause system shutdown and consequently great loss of national economy. The present manuscript proposes two designs for observer-based robust power system stabilizer (PSS) using Linear Matrix Inequality (LMI) approach to damp such oscillations. A model to describe power system dynamics for different loads is derived in the norm-bounded form. The first controller design is based on the derived model to achieve robust stability against load variation. The design is based on a new Bilinear matrix inequality (BMI) condition. The BMI optimization is solved interatively in terms of Linear Matrix Inequality (LMI) framework. The condition contains a symmetric positive definite full matrix to be obtained, rather than the commonly used block diagonal form. The difficulty in finding a feasible solution is thus alleviated. The resulting LMI is of small size, easy to solve. The second PSS design shifts the closed loop poles in a desired region so as to achieve a favorite settling time and damping ratio via a non-iterative solution to a set of LMIs. The approach provides a systematic way to design a robust output feedback PSS which guarantees good dynamic performance for different loads. Simulation results based on single-machine and multi-machine power system models verify the ability of the proposed PSS to satisfy control objectives for a wide range of load conditions. Full Text: PDF DOI: http://dx.doi.org/10.11591/ijece.v6i5.11802

LPV model based BOOST converter's robust variable gain controlling method

Abstract: The invention discloses an LPV model based Boost converter's robust variable gain controlling method which is performed through the following steps: firstly introducing a linear parameter varying model for the Boost converter and polytope optimizing technologies; secondly, based on a linear matrix inequality (LMI) best optimizing method, using state feedback to configure a closed loop pole to a special zone meeting the requirement of dynamic responses; and with the consequence, designing a robust H controller for the Boost converter based on LPV According to the invention, the designed LPV controller enables a Boost converter to maintain stable voltage output and good dynamic characteristics in conditions where sudden changes occur in load resistance or inputted voltage as well as where load disturbs current

Asynchronous traction motor flux linkage observation method based on iron loss model

Abstract: The invention relates to an asynchronous traction motor flux linkage observation method based on an iron loss model. Based on an asynchronous traction motor equivalent circuit considering the iron loss under a two-phase stationary coordinate system, an open loop state observer considering the iron loss is designed; a discrete algorithm for the open loop state observer is improved, and an improved open loop state observer is obtained; and with stator current observation errors as negative feedbacks, a feedback matrix is designed to carry out pole configuration on a closed loop state observer. Through steps such as design of the state observer considering the iron loss, design of the state observer discrete method and closed loop pole configuration, the convergence rate and the observation accuracy of the state observer are improved.

Guardian maps based switching tracking control of large envelope hypersonic vehicles

Abstract: A guardian maps based switching control law is proposed to satisfy the stability and performance requirements for air-breathing hypersonic vehicles(AHSVs), which features large envelope and strong nonlinearity. Firstly, linear parameter varying(LPV) model of AHSV within the entire domain is established based on gap-metric principles. By incorporating PI-LQR method, a set of initial controllers are designed such that closed loop poles lie in desired region. Then, scheduling algorithm is designed for AHSV based on guardian maps. Different from traditional gain scheduling method, which interpolates controller gains designed for several operation points, the proposed method extends the performance of an initial controller carried out on an arbitrary operating point to the entire flight envelope. Finally, nonlinear simulation results are provided, which demonstrate that method proposed in this paper is capable of stabilizing AHSV and ensuring the satisfactory tracking performance within the entire envelope.

Optimization of Closed-Loop Poles for Limited Control Action and Robustness

Abstract: The presented paper exploits optimization and simulation tools of the MATLAB environment to design a robust control system in case of limitations on the controller’s manipulated variable. The design is based on the polynomial approach resulting in the pole-placement problem to be solved. This is addressed numerically by means of the standard MATLAB functions for nonlinear constrained optimization to meet both robustness of the designed loop and constraints on the control input. For this purpose, convenient performance criteria are suggested together with a procedure for the optimization. Presented results of constrained robust control for the AMIRA servo-system show potential of the suggested methodology.

Adaptive control for position control of a pneumatic actuator under variable loads

Abstract: ARTICLE INFORMATION ABSTRACT Original Research Paper Received 14 February 2016 Accepted 07 May 2016 Available Online 19 June 2016 Under a constant loading condition, use of a controller with constant coefficients can be acceptable for servo pneumatic systems. However, in variable loads with widespread changes, more advanced control methods should be considered to achieve desirable performance. In this paper, an adaptive controller is designed and implemented to a variably loaded servo pneumatic system with PWM driven switching valve. In the experimental setup, a pneumatic circuit is used which consists of one PWM driven fast switching valve instead of an expensive servo or proportional valve. In the designed adaptive controller, real time identification of system parameters is performed using input-output data and controller parameters are adjusted instantaneously. “Self-tuning regulators” algorithm in which the desired closed loop poles and zeroes are predefined, is applied to design the proposed controller. The designed controller is applied to the pneumatic actuator via an interface board and its results are compared to results of a PD and a multi model controller. Unlike the proposed method which varies the control parameters continuously according to load variations, in multi-model method the control law is selected among a number of fixed controllers. Experimental results demonstrate the high performance of the adaptive controller under variable loads.

Pseudo innerizing control by state feedback

Abstract: In this paper, we will propose the method of pseudo innerizing by state feedback for a given strictly proper transfer function matrix. The method is an extended result for transfer function matrices which have proper left-inverse, and a generalization of inverted interactorizing for minimum phase transfer function matrices. Numerical examples will be also shown to illustrate the presented method.