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This paper presents a comprehensive three-stage computer-based methodology for the initial setting of the speed and torque controllers for the drives of a paper machine. First, the controller gains are selected based on the figures-of-merit for the frequency- and time-domain responses of each drive to commands and disturbances. After that, the effect of the elastic shafts is considered evaluating the resonant frequencies and two-mass system responses. Finally, the responses of each group of drives to the process commands and/or disturbances of interest are evaluated. The use of the proposed methodology will assure fast and well-behaved responses of each group of drives of the different sections of a paper machine, with minimal field adjustments. Index Terms--Controller setting, disturbance rejection, paper machine drive, speed and torque controllers, torsional oscillations.

Repetitive control (RC) is found to be a high-performance control scheme for constant-voltage constant-frequency (CVCF) pulsewidth-modulated (PWM) converters to eliminate output total harmonic distortion. In this paper, a dual-mode-structure RC (DMRC) is proposed to further improve the control performance of RC. The proposed DMRC controller comprises of two paralleled periodic signal generators: an odd-harmonic one and an even-harmonic one. Without additional complexity and loss of tracking accuracy, DMRC can achieve a faster error convergence rate than the conventional RC does. Moreover, the tracking accuracy of DMRC is higher than that of odd-harmonic RC. In the presence of nonlinear load disturbances and parameter uncertainties, an application example of a DMRC-controlled single-phase PWM inverter is provided to evaluate the proposed DMRC scheme. Systematical experimental results show the effectiveness and superior advantages of the DMRC approach. Index Terms--Even harmonic, odd harmonic, pulsewidth-modulated (PWM) inverter, repetitive control (RC).

The purpose of this note is to present a new approach for stabilizing single-input control-affine systems for which the robust relative degree equals the dimension of the state space. In contrast to the method used in approximate feedback linearization, we employ piecewise constant controllers, which allows us to account for higher order terms. Index Terms--Feedback stabilization, robust relative degree, sampled-data controllers.

In the restructured power industry environment, use of flexible ac transmission systems (FACTS) elements for steady-state corrective control has great economic advantage compared with other corrective control strategies, such as generation rescheduling and load shedding. Due to the requirements of both speed and accuracy for online corrective control, a new linear programming (LP)--based optimal power flow (OPF) algorithm for corrective FACTS control is proposed in this paper to relieve overloads and voltage violations caused by system contingencies. The optimization objective is chosen to minimize the average loadability on highly loaded transmission lines. A new set of parameter sensitivities of FACTS devices are derived to include the operational constraints of FACTS devices during optimization. In order to reduce the effect of errors due to linearization, all sensitivities can be updated during the OPF iterations. The algorithm is implemented with MATLAB and tested on the New England 39-bus system and the WECC 179-bus system. The simulation results show that the proposed LP-based OPF algorithm is effective, fast, and accurate in finding the optimal parameter settings for FACTS devices to solve the problem of overloads and voltage violations. Index Terms--Corrective control, flexible ac transmission systems (FACTS), linear programming (LP), optimal power flow (OPF), overloads, unified power flow controller (UPFC), voltage violations.

A multivariable self-tuning adaptive control scheme used to enhance power system stability in a multimachine environment is presented. The controller is implemented locally for individual generators with supplementary stabilizing signals through the AVR and governor. A discrete multivariable state space model is developed to represent the generator. The recursive subspace identification method based on the projection approximation subspace tracking approach is employed to update generator model parameters online. A generalized predictive control strategy with constraints on the control signals is used. Simulations studies carried out on a five-machine power system without infinite bus show that the proposed multivariable adaptive controller is effective in damping both local and interarea mode oscillations under small as well as large disturbances. The self-coordinating ability of the adaptive controller with the existing conventional controllers is also demonstrated. Index Terms--Adaptive control, multivariable systems, power system stability, system identification.

This paper considers optimal design of an electronic control diesel fuel injection system by considering fuel spray characteristics. The proposed design procedure relies on the assumption that the atomization of fuel spray influences the diesel engine performance, fuel consumption and harmful emission significantly. As a measure of spray atomization the Sauter mean diameter is employed. The design problem is formulated in a form of a multiobjective optimization problem taking into account the Japanese 13 Mode test for diesel engines of commercial vehicles. Two different transformations from the multiobjective to the standard form are proposed and the results are compared to each other. The design variables of the injection system are related to the shape of the cam profile, to the nozzle geometry and to the control parameters influencing the injection quantity and timing. The geometrical properties of the cam profile as well as some injection parameters are kept within acceptable limits by the imposed constraints. [DOI: 10.1115/1.1758248]

In this paper, the performance of a code-division multiple-access (CDMA) cellular system with various traffic types is examined. Traffic integration and resource management are two major issues in the design of the next generation of wireless networks with integrated services. To provide design guidelines for traffic integration, the impact of the line rate (actual transmission bit rate in the radio channel) selection on the system capacity is examined. Since in a CDMA system the signal from one specific user is spread over the entire available bandwidth, the actual bandwidth resource occupied by a user depends on the amount of the transmission power of the user. In this paper, we also address how to assign suitable power levels to the different traffic types. A method for optimizing the power assignment for multiple traffic types is developed. Index Terms - Code-division multiaccess, communication system signaling, fading channels, multimedia communication, power control.

A state-feedback control strategy was recently used to design a pulse-width modulated (PWM) power converter which accommodates disturbances as long as the system remains stable. A robust stability analysis of the closed-loop PWM push-pull dc-dc power converter with a state feedback is presented by using the Kharitonov theorem.

This paper presents a comparative study of different field-oriented rotating-field machines, including the squirrel cage induction machines, series-connected wound rotor induction machines, and synchronous machines. Evaluation of various field-oriented rotating-field machines for high-performance applications is presented. The concept of torque linearization and decoupling control is studied and compared for the various field-oriented motors. Computer simulations, experimental results and space phasor diagrams are employed to illustrate the dynamics of decoupling control for the various field-oriented-control (F.O.C.) systems. The control complexity and parameter sensitivity of various F.O.C. drive motors are compared.

Byline: Faical Mnif This paper describes the development of a mixed VSS swinging-up/balancing controller for the stabilisation of an underactuated mechanical system, the rotating pendulum. The control design is achieved through two stages. The first deals with the swinging-up of the pendulum and the second deals with the balancing of the pendulum about its equilibrium unstable position. The swing-up controller is based on a non-collocated partial feedback linearisation of the underactuated system with a particular choice of the additional control, for which the design is made using the VSS approach. On the other hand, the balancing control is based on the linearised model of the pendulum about its equilibrium unstable position. Simulation results made on a 2-DOF rotating pendulum are given to illustrate the proposed approach.