Silvio Stasi

Politecnico di Bari | Poliba · Dipartimento di Ingegneria Elettrica e dell’Informazione

Power electronics-based three-stage smart transformers (ST) can be seriously damaged by inrush currents and overvoltages during the start-up phase if the control of the stages is not correctly coordinated. Hence, it is crucial to design properly the start-up procedure, especially in case of modular architectures with distributed DC-links. The desig...

In this paper the Feedback Linearization (FL) control theory is applied to a grid-connected Cascaded HBridge (CHB) converter. A DC voltage control is designed taking into account the nonlinear model of the converter and its performances are compared with the performances obtained in case of a conventional PI controller. With the aim to provide a fa...

Accurate detection and identification of faults of induction motors is an important challenge for industry. Often only stator currents/voltages are measurable and, hence, can be analyzed for fault detection. Among current analysis methods, the most attractive ones have low computational cost and little memory requirement for treatment of the measur...

Accurate detection and identification of faults of induction motors is an important challenge for industry. Often only stator currents/voltages are measurable and, hence, can be analyzed for fault detection. Among current analysis methods, the most attractive ones have low computational cost and little memory requirement for treatment of the measur...

DC Smart Grids represent an alternative to traditional AC power distribution systems. The power conversion stage, interfacing the AC and the DC distribution systems, is the enabling technology to manage multiple DC loads and sources. The three-stage Smart Transformer (ST) is a promising solution, because it includes a DC/DC power conversion stage p...

Modular medium voltage power converters have gained increasing attention in context of Smart Transformers (STs) in the electrical distribution grid. A possible ST architecture can be built by a Cascaded H-Bridge (CHB) converter in the Medium Voltage side and Dual Active Bridges (DABs) in the isolation stage. One of the main issues in the CHB contro...

This paper introduces an electrical drives control architecture combining a fractional-order controller and a set-point pre-filter. The former is based on a fractional-order proportional-integral (PI) unit, with a non-integer order integral action, while the latter can be of integer or non-integer type. To satisfy robustness and dynamic performance...

The present paper proposes a reactive power flow control pursuing the active integration of Photovoltaic systems in LV distribution networks. An alternative power flow analysis is performed according to the specific characteristics of LV networks, such as high resistance/reactance ratio and radial topologies. The proposed solution gives high perfor...

Wide bandgap power devices represent a new frontier for More-Electric-Aircraft (MEA) since they can operate with high junction temperature and with reduced switching losses at high switching frequencies. It allows reduction of the cooling system size and high power density. At present the application of wide bandgap devices to MEA power converters...

In Distributed Power Generation Systems (DPGS), the control system of the converter, interfacing the electrical source with the main grid, is generally based on a dual loop cascade control structure where the internal loop is in charge of the current control while the outer loop controls the voltage at the DC link. The DC voltage can be subjected t...

In many applications, fractional-order controllers (FOC) have been usually designed with reference to integer-order (IO) plant models. Namely, even if it is acknowledged that FOC are more effective for fractional-order plants, IO models are usually obtained for control purpose. This paper introduces a special case in which the plant can be really c...

The penetration of Distributed Power Generation Systems (DPGS) is contributing to a low-voltage active distribution grid characterized by the possibility to operate some portions in island mode operation. Power converters, interfacing the DPGS energy source with the rest of the power system, can experience stability problems due to the plant variab...

Half-Bridge Neutral Point Clamped (NPC) converter topology is particularly proper for transformer-less grid-connected photovoltaic (PV) systems since it avoids leakage currents circulation. In case of single-phase applications, resonant controllers are successfully applied to PV converters due to the optimum tracking and harmonic rejection capabili...

In microgrid systems one or more inverters should be grid-forming in order to control the voltage during island mode operation. Usually the voltage regulation is operated controlling the capacitor voltage of the LCL filter interconnected between the converter and the load. In the present paper a cascade control is proposed for a Three-Level Neutral...

In the last years a growing interest towards DC Smart Grids has been registered due to high penetration of distributed generation systems with embedded storage. Trying to foresee the possible future scenarios of the power systems, it can be noticed that DC Smart Grids can be even preferable to AC Smart Grids in terms of flexibility and redundancy s...

An increasing interest is currently verified in DC power distribution systems for the More-Electric Aircrafts (MEA). DC power distribution enables a more efficient use of the generated power and aids in paralleling and load sharing. Transformer Rectifier Units (TRU) and Autotransformer Rectifier Units (ATRU), commonly employed to date, are heavy to...

Due to size and weight limitations, possible integrations of power electronics devices with electrical machines and propulsion engines are welcome in More-Electric-Aircrafts (MEA). Consequently, power converters are required to operate in harsh environments with high temperatures. SiC power devices are preferable in this context since they can tole...

This paper summarizes all research advancements obtained by the Politecnico di Bari through the RES NOVAE Project activities in the field of the smart grids. Such activities have been aimed at bringing substantial contributions in the development of smart grid in medium-voltage and low-voltage distribution systems. Since the scientific approach to...

In the More-Electric-Aircrafts the role of the power converters is fundamental and in the last years the amount of electric power has increased rapidly. In this paper a power conversion stage is proposed and controlled for the Ground Power Unit of a More-Electric-Aircraft. The power conversion topology is based on paralleled converters with interle...

This paper focuses on a design method for feedback and feedforward fractional order control of electromechanical systems. The architecture combines a fractional order proportional-integral controller and a set-point filter. First, the open-loop frequency response is shaped to obtain robustness specifications and to approximate an optimal feedback s...

In this paper the authors present a model suitable to convert ultralight airplanes propulsion system from endothermic into electric, focusing only on the power management issues, discarding the mechanical and dynamic ones. The model developed represents a tool to correctly size the propulsion and energy management system of ultra-light aircrafts de...

This paper surveys the proposed solutions for the design of an ultra-light Unmanned Aerial Vehicles, showing the most recent advances in technology for the power system of the design. In particular this paper focuses on the electrical components of the project, showing a brief review of the single objects and their applicability for the design of a...

This paper presents design considerations for a low altitude short endurance electric powered ultralight aircraft with solar panels. The paper focuses on the conversion of the ultralight propulsion system from endothermic into electric, discarding the mechanic and dynamic issues from the design, and addressing the sizing consideration principall...

This paper presents design considerations for a low altitude short endurance electric powered ultralight aircraft with solar panels. The paper focuses on the conversion of the ultralight propulsion system from endothermic into electric, discarding the mechanic and dynamic issues from the design, and addressing the sizing consideration principally o...

This paper proposes the employment of the differential evolution (DE) to offline optimize the covariance matrices of a new reduced delayed-state Kalman-filter (DSKF)-based algorithm which estimates the stator-flux linkage components, in the stationary reference frame, to realize sensorless control of induction motors (IMs). The DSKF-based algorithm...

This paper proposes a speed-sensorless stator field orientation control (SFOC) of IM drives based on a delayed-state Kalman filter (DSKF) optimally tuned with the differential evolution (DE) algorithm. The DSKF estimates the stator flux components in the stationary reference frame, using the derivatives of the stator flux components as mathematical...

Direct drives with linear permanent magnet synchronous motors (LPMSMs) are recently attracting the attention of both industry and academia. On the one hand such electric drives permit to reduce size and increase reliability thanks to the lack of mechanical reduction and transmission devices. On the other hand precision positioning requires linear p...

This paper proposes to use a differential evolution (DE) algorithm to obtain the optimal covariance matrices of a new reduced delayed-state Kalman filter (DSKF) based algorithm to realize sensorless induction motor drives. We propose to use a novel simple stator flux oriented-sliding mode (SFOSM) control scheme in conjunction with the optimized DSK...

This paper proposes a new reduced delayed-state Kalman filter (DSKF) based algorithm to realize the speed-sensorless vector control of induction motor. This algorithm estimates the stator flux components in the stationary reference frame, using the derivatives of the stator flux components as mathematical model and the stator voltage equations as o...

This paper proposes a stator flux oriented (SFO) control scheme of induction motors using variable-saturation regulators. The traditional SFO control scheme consists in the d-axis current component, torque, stator flux, and speed loops with four PI-type controllers. The proposed control scheme uses two regulators with variable-saturation in such a...

This paper proposes to use a simple stator flux oriented-sliding mode control scheme in conjunction with a novel delayed-state Kalman filter based algorithm, estimating the stator flux linkage components, to realize sensorless induction motor drives. This control scheme has closed loops of torque and stator flux without Pi-type controllers and a mi...

This paper studies the problem of the optimal control design of permanent magnet synchronous motor (PMSM) drives taking into account the noise due to sensors and measurement devices. The problem is analyzed by means of an experimental approach which considers noisy data returned by the real plant (on-line). In other words, each fitness evaluation d...

This paper focuses on a simple method of achieving optimal transient torque responses in indirect rotor flux orientation (IRFO) control of induction motors having skewed rotor bars. When the rotor bars are skewed, the q-axis stator current component produces its own field which is in the direction of the rotor field due the d-axis stator current co...

This paper presents a novel PMSM sensorless control scheme based on a linear Kalman filter (LKF) observer. The LKF algorithm estimates the rotor flux components in the stator reference frame by measuring stator currents and voltages, and using a mathematical model based on rotor equations of the motor, and an observation model based on the imaginar...

This paper presents a novel PMSM sensorless control scheme based on a linear Kalman filter (LKF) observer. The LKF algorithm estimates the rotor flux components in the stator reference frame by measuring stator currents and voltages, and using a mathematical model based on rotor equations of the motor, and an observation model based on the imaginar...

This paper presents some analysis techniques of the space vector of voltages induced in the stator windings after supply disconnection, to detect broken rotor bars in squirrel-cage induction machines. When the motor is disconnected from the supply no currents flow in the stator windings and the voltages measurable at its terminals are due to flux p...

This paper presents some analysis techniques of the space-vector of voltages induced in the stator windings after supply disconnection, to detect broken rotor bars in squirrel cage induction machines. When the motor is disconnected from the supply no currents flow in the stator windings and the voltages measurable at its terminals are due to flux p...

This paper presents some analysis techniques of the space-vector of voltages induced in the stator windings after supply disconnection, to detect broken rotor bars in squirrel cage induction machines. When the motor is disconnected from the supply no currents flow in the stator windings and the voltages measurable at its terminals are due to flux p...

This paper presents a performance comparison among some of the most effective spectral estimation techniques applied to the fault diagnosis of induction machines. The diagnostic test is based on the analysis of the current space vector during motor starting via short-time analysis, using a sliding window and different spectral estimation algorithms...

This paper presents a new technique to diagnose broken rotor bars in squirrel cage induction machines. The technique is based on the analysis of the current space vector during motor starting via Short- Time MUSIC (STMUSIC) pseudo-spectrum. Differently from most of the diagnostic techniques already proposed in the technical literature, the approach...

This paper presents a novel strategy to guarantee continuous working of a Surface Permanent Magnet Synchronous Motor (SPMSM) drive even when position-sensor failure occurs. This strategy consists in using a sliding-mode speed observer, in place of a second sensor, without additional cost. The speed observer needs an initial parameter tuning and has...

In this paper, we introduce two novel closed-loop current control techniques for rotor alignment in a phase axis direction in PMSM drives. This alignment procedure is used both in sensor and sensorless PMSM drives to correctly implement vector control strategies. The two novel closed-loop current control techniques employ PI and sliding-mode contro...

This paper presents a novel PMSM sensorless control scheme based on a linear Kalman filter (LKF) observer. The LKF algorithm is able to estimate rotor position and current components in the stator reference frame by measuring stator currents, and using a mathematical model based on the voltage equations of motor. The proposed observer is linear but...

This paper presents a novel PMSM sensorless control scheme. The observed rotor position is obtained from the active and reactive electromagnetic torque calculated in both the stationary α−β and rotor d-q reference frame. This observed rotor position is improved by the addition of a term, derived from the d-axis current controller voltage output, an...

In questo lavoro si esaminano varie tecniche di controllo sensorless di motori sincroni a magneti permanenti e a riluttanza, allo scopo di individuare la tecnica più adatta per l'implementazione su microcontrollori a basso costo.

This paper proposes the application of two new Kalman filter-based algorithms to realise a speed-sensorless vector control of induction motor drives. The first one is a linear Kalman filter (LKF)-based algorithm that estimates the equivalent disturbance torque, which is compensated by the injection of a feedforward signal. The latter is an extended...

This paper presents a simple method to design four fuzzy controllers of a fully digital vector-controlled induction motor drive. The outer controllers realise the usual rotor speed and flux control, while the inner controllers are used to control the d- and q-axis stator current components. The design method is based on physical relationships, beca...

This paper proposes the use of a neural network(NN) for the induction motor rotor flux estimation and presents a comparison with two model-based observers. The paper deals with a neural network having eight inputs, two outputs, and one hidden layer with six nodes using sigmoidal-functions. The NN outputs are the alfa,beta components of the rotor fl...

This paper deals with the application of a neural observer for the estimation of induction motor state. It focuses on a simple neural observer having neural-network (NN) architecture with six inputs, two flux state outputs, and one hidden layer with a few nodes using sigmoidal-functions. This NN is recurrent, i.e. the two past state outputs are fed...

This paper proposes a comparison between the performances of an adaptive flux observer and those of an extended Kalman filter-based algorithm, used to estimate the rotor flux components, rotor resistance, and inverse rotor time constant, in direct vector-controlled induction motor drives. The estimates are obtained by measuring stator voltages, sta...

This paper presents the application or the Wigner-Ville distribution (WVD) to the spectral analysis of the voltage and current systems at the terminals of an inverter-fed induction motor. The spectral- leakage problem is studied and the attention is rocused on the effect of wlndowing. New suitable windows are proposed to provide high-resolution sig...

A new control strategy for joint trajectory tracking of robot manipulators is proposed in this paper. The design of the position control system for each joint is based on state feedback technique with two feedforward actions compensating the modelled joint drive system dynamics and the equivalent disturbance, respectively. The independent state fee...

This paper deals with the rotor speed detection in induction motor drives when very low-speed operation and high performances are required. The application of two Kalman filter-based algorithms to estimate the rotor flux components, rotor speed and position, and equivalent disturbance is proposed. The extended Kalman filter-based algorithm is used...

Nel presente lavoro si propone l'applicazione di uno stimatore neurale dello stato di un motore ad induzione. In particolare l'osservatore proposto è in grado di fornire stime sufficientemente accurate delle componenti del flusso di statore o di rotore. Tali stime possono essere usate per effettuare il controllo vettori aie di un motore ad induzion...

The knowledge of the rotor flux space-vector position is essential to implement the direct field-oriented control strategy to induction motor drives. In this paper a delayed state Kalman filter has been used to estimate the rotor flux position and the parameters of an induction motor. The main advantage of the proposed algorithm may be resumed as f...

The paper proposes the application of the fuzzy logic control to a d.c./d.c. Boost converter used in the power conditioning circuit of a wind stand-alone generation system. A detailed description and the non linear model of the proposed converter is given, together with the set of fuzzy control rules and term sets used in the specific application f...

The paper presents an original methodology to solve the problems of vector control degradation, due to the changes of motor electrical parameters, and the inadequate rejection of external disturbances and load variations, in induction motor drives. The solution of the first problem is reached by using a new algorithm, based on the extended Kalman f...

This paper presents a new method of estimating the speed, rotor flux components, and parameters of a vector controlled induction motor (IM) using an extended Kalman filter. The estimates are obtained by only measuring the line voltages and currents of the machine. The estimated speed and flux are used for vector control and overall speed control. T...

A new robust control strategy for robot manipulators is proposed in this paper. The robustness of the control system is achieved by a new fuzzy controller. The controller outputs, that are functions of the position tracking errors and their variations between two running sampled instants, have to compensate the joint dynamics, dynamic coupling amon...

This paper proposes the contemporaneous application of two Kalman filter-based algorithms to realise a robust control of induction motor drives. The first one (EKF, extended Kalman filter) is used to obtain a correct implementation of direct vector control, since it estimates the rotor flux components, rotor time constant, rotor resistance, and lea...

A new robust control strategy for robot manipulators is proposed in this paper. The robustness of the control system is achieved by a new fuzzy controller. The controller outputs, that are functions of the position tracking errors and their variations between two running sampled instants, have to compensate the joint dynamics, dynamic coupling amon...

This paper deals with a new delayed state Kalman filter to be used to simultaneously estimate all the induction motor parameters and the rotor flux space vector position that are necessary to correctly implement direct field-oriented control schemes. The algorithm is based on the extended Kalman filter theory and only uses machine quantities that c...

A new control strategy for robotic manipulators is proposed in this paper. The position control system design is based on a joint local PD control technique with a feedforward compensation term. The PD controller is designed considering a flrst-order linear reference model for each joint. The controller gains are tuned on average values of the iner...

Nel lavoro si propone di utilizzare un nuovo compensatore del disturbo equivalente, basato sulla logica fuzzy, per il controllo di posizione di un azionamento con motore sincrono a magneti permanenti (PMSM). Il ricorso ad un tale tipo di compensatore consente di modellare il sistema azionamento come un sistema meccanico -lineare tempoinvariante con...

The paper describes a new robust controller for the positioning of a servomotor. The position control system design is based on pole placement by the state feedback method with an additional feedforward compensation term. The state feedback controller gains are tuned on the nominal parameters of the motor and load. To obtain the specified ideal dyn...

This paper proposes a self-tuning control system for the positioning of a PM synchronous motor. The auto-tuning control system is realized with a conventional position P-regulator, a derivative position feedback with adjustable gain, and a new online estimator, based on the extended Kalman filter theory, which provides the estimates to update the g...

This paper proposes to apply the Wigner-Ville distribution (WVD) or, alternatively, a "new" time-frequency representation (TFR) to voltage and current signals of inverter drives to monitor instantaneous complex power, voltage and current space-vectors in the time-frequency domain. The WVD and TFR satisfy the following properties: the frequency inte...

A reduced-order algorithm for estimating the rotor flux components of induction motors with schemes such as field-oriented control is described. The algorithm is based on the extended Kalman filter (EKF) theory and estimates the desired quantities online using only measurements of the stator voltages and currents and the rotor speed. The online ada...

The paper deals with the spectral monitoring of the instantaneous symmetrical components representing the unbalanced and distorted three-phase voltage and current systems generated by inverters supplying AC motors. It is shown that the spectra of the analytic signals corresponding to the above-mentioned components contain the harmonic symmetrical c...

The authors describe the application of the extended Kalman filter theory to the parameter and state estimation of a permanent-magnet synchronous motor drive for a microprocessor based adaptive speed control in the presence of a variable load. The electronically commutated permanent magnet synchronous motor is controlled according to the principle...

The increasing use of power electronics apparatus in three phase industrial systems is giving rise to transmission of power with high level of harmonic distortion. As a consequence, the problem of the definition and measurement of powers and current components under unbalanced and distorted conditions is of extreme practical and theoretical importa...

It is known that the application of the field-oriented control strategy to induction motors needs the knowledge of the rotor flux components or the rotor resistance. The aim of this work is to show a method to estimate these quantities, based on the Kalman filter extended theory. The state equation of the Kalman filter results to be non linear beca...

Permanent magnet synchronous motor drives are widely used in industrial applications because of their high performance. The use of field orientation control strategy gives external characteristics similar to those of well known dc drives without the need for slip rings and a field supply. In this paper we propose a new scheme for adaptive position...