Search results for "Observer"
showing 10 items of 345 documents
On the design of observers robust to load variations for synchronous converters
2015
Due to the ever growing concern on energy efficiency issues, synchronous rectification gained increasing attention in recent years. In the semiconductor industry fast controllers developed for DC-DC converters are typically based on inductor current measures. In this context system costs and performances strictly depend on the current sensor and its proper design. In this paper we present a sensorless synchronous approach based on a current observer. The same observer formulation is valid for the three standard DC-DC converters, simplifying its design for different configurations. Furthermore the designed observers are proven to be robust against load variations, the most uncertain paramete…
Sliding mode torque control of an induction motor for automotive application with sliding mode flux observer
2016
In this paper, the performance of two control systems of induction motors for automotive applications were compared in order to highlight the differences in terms of response speed, robustness and noise immunity. The first system is realized through a field-oriented control with PI controllers, while the second system is realized through a field-oriented control with Sliding Mode Controllers. Both controls are designed to follow the torque references as required for the vehicles and are tested with typical load profiles of vehicles. It also designed a sliding mode observer flux.
Dynamic performance enhancement of AC/DC PFC boost converters by means of MRAS observers
2015
Controlling a Power Factor Corrected (PFC) boost converter is not a trivial task, because the higher the dynamic performance, the higher is the input current distortion. On the other hand, recent applications of these converters require fast transients in response to disturbances, such as sudden variations of load power, reference voltage and input voltage. Better performance can be obtained adding a feedforward action to the traditional control scheme, using observers to estimate the input voltage and the output current. However, the actual improvement depends on the dynamic performance of the chosen observers. This paper aims at evaluating the applicability and the performance of differen…
Guidelines for the design and implementation of the ARPCC control applied to grid-connected converters
2013
Abstract This paper presents implementation details of the adaptive robust predictive current control (ARPCC) applied to a grid-connected converter, such as feed-forward cancellation protocol, the selection of the observer gain and adaptive parameters or the sampling options, needed to get the best performance of this control. The feed-forward term cancellation permits to achieve a very low harmonic distortion in current waveforms when the voltage sensing circuits are well calibrated. A detailed gain adjustment protocol of the voltage sensing circuits is presented in this paper. Moreover, a control design procedure based on the observer gain L o boundaries and the adaptive parameters has be…
Method for designing PI-type fuzzy controllers for induction motor drives
2001
The paper illustrates a new systematic method for designing PI-type fuzzy controllers for direct field-oriented controlled induction motor drives. First, linear and decoupled models expressing the dynamics of speed, rotor flux, direct and inquadrature stator currents are derived using a nonlinear static compensator and choosing convenient input variables. Then, to guide the dynamics of the above quantities, four conventional PI controllers are designed independently, choosing their bandwidths conveniently. Finally, the input and output scale factors of PI-type fuzzy controllers are derived from the conventional PI controller parameters. The whole drive controller also includes a rotor flux …
Sliding-mode observer based sensor-less control of a small wind energy conversion system
2015
Small wind turbines are becoming an attractive solution for household applications. These micro generation units can be used as standalone applications or grid connected applications. However to get the full potential benefits of these wind turbines, systems should be low cost and reliable. Introducing the wind speed and rotor speed sensors at the generator shaft may reduce the reliability of small wind turbines. In this study, a grid connected sensor-less 5 kW small wind energy conversion system has been studied. The maximum power point tracking method of the wind turbine is totally independent from wind speed and rotor speed measurements. Optimum rotor speed and actual rotor speed are est…
Sensorless small wind turbine with a sliding-mode observer for water heating applications
2015
Water heating applications consume a considerable portion of electricity demand in most of countries. Small wind turbines are one of attractive alternatives for grid electricity based water heating systems. Wind energy can be converted to heat energy in a high efficient manner. However it is essential that wind turbine based water heating systems should be economical and reliable. Maximum power point tracking algorithm of most of available wind turbines requires information from a wind speed sensor and a rotor speed sensor which reduces the reliability of the system. In this paper, the proposed 5 kW wind turbine does not require external wind speed sensors and rotor speed sensors. The syste…
A Robust Predictive Current Control for Three-Phase Grid-Connected Inverters
2009
This paper presents a new predictive control algorithm for grid-connected current-controlled inverters. The control combines a two-sample deadbeat control law with a Luenberger observer to estimate the future value of the grid currents. The resulting control offers robustness against the computational delay inherent in the digital implementation and considerably enhances the gain and phase margins of the previous predictive controls while maintaining the high-speed response typical of the deadbeat controllers.
daptive Backstepping Control of Nonlinear Hydraulic-Mechanical System Including Valve Dynamics
2010
Published version of an article from the journal: Modeling Identification and Control. Also available from publisher: http://dx.doi.org/10.4173/mic.2010.1.3 The main contribution of the paper is the development of an adaptive backstepping controller for a nonlinear hydraulic-mechanical system considering valve dynamics. The paper also compares the performance of two variants of an adaptive backstepping tracking controller with a simple PI controller. The results show that the backstepping controller considering valve dynamics achieves significantly better tracking performance than the PI controller, while handling uncertain parameters related to internal leakage, friction, the orifice equat…
Robust energy-to-peak sideslip angle estimation with applications to ground vehicles
2015
Abstract In this paper, the observer design problem for the sideslip angle of ground vehicles is investigated. The sideslip angle is an important signal for the vehicle lateral stability, which is not measurable by using an affordable physical sensor. Therefore, we aim to estimate the sideslip angle with the yaw rate measurements by employing the vehicle dynamics. The nonlinear lateral dynamics is modeled firstly. As the tyre model is nonlinear and the road adhesive coefficient is subject to a large variation, the nonlinear lateral dynamics is transformed into an uncertain model. Considering the variation of longitudinal velocity, an uncertain linear-parameter-varying (LPV) system is obtain…