Hybrid Modelling and Control of a Class of Power Converters With Triangular-Carrier PWM Inputs

In this paper, a new control design procedure for a class of power converters based on hybrid dynamical systems theory is presented. The continuous-time dynamics, as voltage and current signals, and discrete-time dynamics, as the on- off state of the switches, are captured with a hybrid model. This model avoids the use of averaged and approximated models and includes the PWM as well as the sample-and-hold mechanism, commonly used in the industry. Then, another simplified hybrid system, whose trajectories match with the original one, is selected to design the controller and to analyse stability properties. Finally, an estimation of the chattering in steady state of the voltage and current signals is provided. The results are validated through simulation and experiments.MCIN/ AEI Project PID2019-105890RJ-I00MCIN/ AEI Project PID2019-109071RB-I0

Feedback Linearization Based Nonlinear Control of SynRM Drives Accounting for Self- and Cross-Saturation

This article proposes a nonlinear controller based on feedback linearization (FL) for synchronous reluctance motor (SynRM) drives which takes into consideration the magnetic saturation. The proposed nonlinear FL control based control technique has been developed starting from the theoretical definition of an original dynamic model of the SynRM taking into consideration both the self- and the cross-saturation effects. Such a control technique permits the dynamics of both the speed and axis flux loops to be maintained constant independently from the load and the saturation of the iron core in both constant flux and variable direct axis flux operating conditions. Finally, sensitivity of the performance of the proposed FL control versus the variation of the main motor parameters has been verified. The proposed technique has been tested experimentally on a suitably developed test setup. The proposed FL control has been further compared with the classic field-oriented control (FOC) in both constant flux and variable flux working conditions

Space-vector state dynamic model of SynRM considering self- and cross-saturation and related parameter identification

This study proposes a state formulation of the space-vector dynamic model of the Synchronous Reluctance Motor (SynRM) considering both saturation and cross-saturation effects. The proposed model adopts the stator currents as state variables and has been theoretically developed in both the rotor and stator reference frames. The proposed magnetic model is based on a flux versus current approach and relies on the knowledge of 11 parameters. Starting from the definition of a suitable co-energy variation function, new flux versus current functions have been initially developed, based on the hyperbolic functions and, consequently, the static and dynamic inductance versus current functions have been deduced. The dynamic inductance functions have been derived so to fulfill the reciprocity conditions. This study presents also a technique for the estimation of the parameters of the proposed magnetic model, which is based on stand-still tests without the need to lock the rotor. The identification process has been performed based on the minimization of a suitably defined error function including the difference between the measured and estimated stator fluxes. The proposed parameter estimation technique has been tested in both numerical simulation and experimentally on a suitably developed test set-up, permitting the experimental validation of the proposed model

Input-Output Feedback Linearization Control of a Linear Induction Motor Taking Into Consideration Its Dynamic End-Effects and Iron Losses

This article proposes a new input–output feedback linearization control (FLC) technique of linear induction motors (LIMs), taking into consideration both the dynamic end-effects and the iron losses. Starting from a previously conceived dynamic model, including the dynamic end-effects and the iron losses, all the theoretical framework of the FLC has been developed. The proposed FLC improves a previous version of FLC in accounting also the iron losses, which in LIMs with fixed-secondary sheet play a pivotal role more than in rotating induction motors (RIMs). The proposed FLC has been experimentally tested on a suitably developed test setup, and experimental comparisons between the proposed FLC, the classic field-oriented control and a previously developed FLC, not accounting for the iron losses, have been shown in variable flux working conditions

Forest accessibility, Madonie mountains (northern Sicily, Italy): implementing a GIS decision support system

Valorisation and sustainable exploitation of woody biomass from cultivation interventions might be an important opportunity to track alternative development trails for rural communities in natural protected areas. The governance of Mediterranean protected areas is characterized by overlapping, sometimes conflicting institutions, stakeholders and regulations, causing negative impacts on decision-making processes. We present an open source GIS-based decision support system tool for mapping forest accessibility and optimizing woody biomass extraction. Two models were implemented to support forest managers during the decision-making process in designing and managing wood-energy supply chains. The optimal grid resolution to run the models was determined via a Least Cost Path analysis. The models were executed at different scales, performing satisfactorily when distances between recorded and modelled paths were lower than the grid unit. The higher the scale, the more the percentile of distances lower than the grid unit. The models were validated in Madonie mountains, Sicily, Italy

Robust Disturbance Rejection Control of DC/DC Interleaved Boost Converters with Additional Sliding Mode Component

Interleaved DC/DC boost converters are nowadays widely studied due to their properties of reducing the current ripple and increasing fault tolerance. This paper describes a control method that allows good output voltage regulation, together with robustness against parameter uncertainties, deviation of the supply voltage of the source, and load deviation. These objectives are obtained by determining an equivalent circuital scheme of the interleaved boost and associating to this scheme a linear mathematical model by means of the exact linearization method. Subsequently, trajectory tracking control techniques are employed based on disturbance compensation and a sliding mode component is added to cope with parameter uncertainties and possible compensation errors. The controller, applied to the above equivalent conventional boost model, allows to command the duty cycle of single phases of the Mosfets. This controller uses the output voltage and the currents flowing in the phases of the converter as feedback variables. Simulation results show the validity of the proposed approach

GA-Based Off-Line Parameter Estimation of the Induction Motor Model Including Magnetic Saturation and Iron Losses

This paper, starting from recent papers in the scientific literature dealing with Induction Motor (IM) dynamic modelling, as a first step, improves its space-vector dynamic model, including both the magnetic saturation and iron losses; particularly it takes into account the dependence of the magnetic saturation by the stator leakage inductance, as a further effect of the load. Afterwards, it proposes an off-line technique for the estimation of electrical parameters of this model, which is based on Genetic Algorithms (GA). The proposed method is based on input-output measurements and needs neither the machine design geometrical data nor a FEA of the machine. It focuses on the application of an algorithm based on the minimization of a suitable cost function depending on the stator current error. The proposed electrical parameters estimation method has been initially tested in numerical simulation and further verified experimentally on a suitably developed test set-up

Implementation and Comparison of SiC and GaN switches for EV Fast Recharging Systems

Wide bandgap material-based devices allow faster switching frequency and exhibit smaller losses than traditional Si devices; nevertheless, a complete understanding of the functioning of these new devices remains poorly understood. A fast battery charger for electric vehicles based on a converter employing SiC and GaN devices is here reported Besides, these two technologies are experimentally compared, in the same layout, to highlights their performance in terms of electrical dynamic and electromagnetic compatibility

A time-varying observer for linear systems with asynchronous discrete-time measurements

International audienceIn this paper we propose a time-varying observer for a linear continuous-time plant with asynchronous discrete-time measurements. The proposed observer is contextualized in the hybrid systems framework providing an elegant setting for the proposed solution. In particular some theoretical tools are provided, in terms of LMIs, certifying asymptotic stability of a certain compact set where the estimation error is zero. Moreover the case of asynchronous measurements is considered, i.e. when the measurements are not provided in well defined time instants, but they occur at an arbitrary time in a certain time interval. A design procedure based on the numerical solution of an infinite-dimensional LMI is also proposed, leading to a time-varying observer gain. Finally a numerical example shows the effectiveness of the proposed approach

State Observer with Round-Robin Aperiodic Sampled Measurements with Jitter

International audienceA sampled-data observer is proposed for linear continuous-time systems whose outputs are sequentially sampled via non-uniform sampling intervals repeating a prescribed Round-Robin sequence. With constant sampling intervals (jitter-free case) we provide constructive necessary and sufficient conditions for the design of an asymptotic continuous-discrete observer whose estimation error is input-to-state stable (ISS) from process disturbances and measurement noise. We use a time-varying gain depending on the elapsed time since the last measurement. With non-constant sampling intervals (jitter-tolerant case), our design conditions are only sufficient. A suspension system example shows the effectiveness of the proposed approach