IEEE Transactions on Control Systems Technology, 2003
This paper presents the synthesis and practical implementation of a robust digital differentiator... more This paper presents the synthesis and practical implementation of a robust digital differentiator that provides the first and second derivative of a sampled smooth signal. The robustness of the proposed digital device, based on second-order slidingmodes (2-SMs), is analyzed with respect to measurement errors. Experimental results on an induction motor (IM) drive show that fast and accurate estimates of speed and torque can be obtained in several operating conditions by double differentiation of the encoder position measurement.
In this contribution we report on a new module prototype of high concentrator photovoltaic (HCPV)... more In this contribution we report on a new module prototype of high concentrator photovoltaic (HCPV). The optical design of the presented prototype is based on two optical elements: high quality Fresnel lenses and aluminum homogenizers, while for the realisation of the photovoltaic receiver a triple junction solar cell has been used. The whole device has been designed and developed as a cost effective product providing at the same time high value for the output power. Measurements aimed at determining electrical characteristics have been performed both on single concentrator cells and on the module realised by connecting together four single photovoltaic receivers. Thermographic measurements have been carried out in order to determine the zones where heating effects have occurred during the operating conditions. The paper purpose is to provide an overall presentation and accurate description of the final version of HCPV new module prototype that is the result of the collaboration of Italian National Institute for Astrophysics of Cagliari, Electrical and Electronic Engineering Department of University of Cagliari and Sardegna Ricerche Photovoltaic Laboratory.
The rotor speed estimation problem in electrical drives, based on shaft encoder measurements, has... more The rotor speed estimation problem in electrical drives, based on shaft encoder measurements, has been dealt with by means of a digital approximate differentiator. The proposed differentiator is based on a digital VSC which is able to perform real 2-sliding modes, so that the observer discontinuous control is confined to the second total derivative of the available encoder signal estimate, and its first derivative is then continuous. Simulation and experimental results, conducted on a field oriented induction motor drive, show the good behaviour of the proposed approximate differentiator, which has been compared with the Matlab-Simulink differentiator algorithm by using a DSP-based system.
An overview of V2G (vehicle-to-grid) technology is presented in this paper. It aims to highlight ... more An overview of V2G (vehicle-to-grid) technology is presented in this paper. It aims to highlight the main features, opportunities and requirements of V2G. Thus, after briefly resuming the most popular charging strategies for PEVs (plug-in electric vehicles), the V2G concept is introduced, especially highlighting its potentiality as a revenue opportunity for PEV owners; this is mainly due to the V2G ability to provide ancillary services, such as load leveling, regulation and reserve. Such solutions have been thoroughly investigated in the literature from both the economic and technical points of view and are here reported. In addition, V2G requirements such as mobility needs, charging stations availability and appropriate PEV aggregative architectures are properly taken into account. Finally, future developments and scenarios have also been reported.
Proceedings of Second International Conference on Power Electronics and Drive Systems, 1997
A general approach to direct torque and flux control of induction motor fed by VSI is presented i... more A general approach to direct torque and flux control of induction motor fed by VSI is presented in the paper. The inverter switching patterns are generated as a function of the reference values both of the electromagnetic torque and of the controlled flux. In particular, the proposed control algorithm is independent on which kind of flux is controlled, rotor or stator one. The results obtained by means of a real time simulation show that the proposed control strategy allows to obtain a very fast and accurate response of the drive.
ISIE '99. Proceedings of the IEEE International Symposium on Industrial Electronics (Cat. No.99TH8465)
This paper deals with the variable structure system (VSS) approach to the permanent magnet (PM) D... more This paper deals with the variable structure system (VSS) approach to the permanent magnet (PM) DC motor speed control. The aim of this treatment is that of proposing a novel scheme based on second order sliding mode control (SOSMC) technique. The main features of the proposed scheme are the robustness against heavy motor parameters variations and the avoidance of the current loop implementation, which is generally requested by traditional approaches. The precise knowledge of the motor parameters is not requested, and the insensitivity to smooth unknown load torque disturbance is obtained. Moreover, some issues associated with the practical implementation of the control scheme, mainly linked to the current ripple amplitude, are discussed, and experimental investigations are reported to show the effectiveness of the proposed approach
A novel management strategy for Electric Vehicles (EVs) storage systems is proposed in this paper... more A novel management strategy for Electric Vehicles (EVs) storage systems is proposed in this paper. It aims to enhance the Renewable Energy Sources (RES) exploitation hour by hour, but prioritizing the EV mobility requirements. A mathematical modelling of the mobility system is firstly developed in order to estimate, hour by hour, the amount of EVs available to exchange energy with
ABSTRACT A novel flux-weakening approach suitable for Surface-Mounted Permanent Magnet Synchronou... more ABSTRACT A novel flux-weakening approach suitable for Surface-Mounted Permanent Magnet Synchronous Machines (SPMs) is presented in this paper. It consists in directly synthesizing the square magnitudes of the current and voltage vectors on the basis of an accurate SPM sampled-data model and of the reference torque profile. This enables optimal and easy management of SPM operating constraints, i.e. current limitation and voltage saturation, on the basis of which the dq reference current profile can be achieved, whatever the SPM speed and Constant Power Speed Ratio (CPSR) is, i.e. finite or infinite. The effectiveness of the proposed flux-weakening approach is highlighted by both simulation and experimental results, which refer to SPMs with finite and/or infinite CPSR and driven by a predictive control algorithm.
IECON 2013 - 39th Annual Conference of the IEEE Industrial Electronics Society, 2013
ABSTRACT The continuing development and the increasing diffusion of concentrator photovoltaic (CP... more ABSTRACT The continuing development and the increasing diffusion of concentrator photovoltaic (CPV) systems highlight the lack of specific international standards in the CPV power rating and characterization field. Presently, the only reference standard for CPV cells and modules is the IEC 62108, which does not impose minimum requirements for solar trackers and simulators used in the qualification process of CPV modules. Nevertheless, the overall quality of CPV tests is strictly associated to the technical specifications of these devices. The aim of this paper is to define optical and radiometric properties of solar simulators and the pointing accuracy of solar trackers, required for testing CPV devices and rating their performance. The results of experimental analyses on real CPV systems have been reported, highlighting the criticalities of indoor and outdoor CPV characterization. Finally an outdoor light soaking test, executed under MPPT conditions, has been proposed for the qualification process of high concentrating photovoltaic devices.
... Auchen. Germany, 2004 For all these reasons the only method actually used to predict the EM1 ... more ... Auchen. Germany, 2004 For all these reasons the only method actually used to predict the EM1 behavior of a given system is the numeric simulation.[3] Y, = jY,C tan[fl(;+Ad)] ... k = 1,2 .... N -1; Y,, + jY,' tan@d) Y l + jY,, tan@d)' '%.I) 'Zk+I = yt y,,+, = y,C Y,' + jY,, tan[fl[F+Ad)] ...
One of the most recent topics in variable-structure systems theory is represented by the second-o... more One of the most recent topics in variable-structure systems theory is represented by the second-order sliding-mode control (2-SMC) methodology. This approach guarantees the same robustness and dynamic performance of traditional first-order SMC algorithms, and, at the same time, attenuates the chattering phenomenon, which is the main drawback in the actual implementation of this technique. In the present paper, a recently-proposed 2-SMC algorithm is used to synthesize a robust dc-drive control system which does not require current feedback and demands only rough information about the actual motor parameters. Stability and performance are analyzed, and an experimental comparison with a proportional-integral-based control scheme is reported.
ABSTRACT With reference to speed controlled induction motor drives, an algorithm which allows the... more ABSTRACT With reference to speed controlled induction motor drives, an algorithm which allows the on-line estimation either of the speed and one motor parameter or, alternatively, of two motor parameters, is presented in the paper. The results obtained by simulation fully confirm the validity of the proposed algorithm. Finally, the problems arising from the implementation of the proposed algorithm on a DSP-based control hardware are analysed
ABSTRACT An optimal energy storage system (ESS) management procedure devoted to full renewable en... more ABSTRACT An optimal energy storage system (ESS) management procedure devoted to full renewable energy sources (RESs) exploitation is presented in this paper. It consists of an appropriate scheduling procedure and a real-time control strategy, which both aim to increase the RES penetration level as much as possible. In particular, the one-day-ahead scheduling procedure synthesizes the combined RES-ESS energy production profile with the aim of minimizing the RES energy production curtailments by means of ESS energy buffering. The real-time control strategy is developed in order to track the scheduled profile as well as possible by mitigating forecasting errors, thus improving RES reliability. The worth and effectiveness of the proposed management procedure is verified through a wide simulation study, which is carried out by means of the Matlab software package.
ABSTRACT An improved control algorithm for a multilevel DTC drive is proposed in the present pape... more ABSTRACT An improved control algorithm for a multilevel DTC drive is proposed in the present paper. It allows avoidance of the demagnetisation phenomena at zero speed and reduction of the torque ripple without increasing the switching frequency. In particular, the reference torque time derivative is used with the aim of optimising the NPC converter voltage selection criteria, during torque and load variations. Results of extensive simulations are presented and discussed to prove the effectiveness of the proposed multilevel DTC drive
The integration of small scale concentrating solar power (CSP) in an industrial district, in orde... more The integration of small scale concentrating solar power (CSP) in an industrial district, in order to develop a microgrid fully supplied by renewable energy sources, is presented in this paper. The plant aims to assess in real operating conditions, the performance, the effectiveness and the reliability of small-scale concentrating solar power technologies in the field of distributed generation. In particular, the potentiality of small scale CSP with thermal storage to supply dispatchable electricity to an industrial microgrid will be investigated. The microgrid will be realized in the municipal waste treatment plant of the Industrial Consortium of Villacidro, in southern Sardinia (Italy), which already includes a biogas power plant. In order to achieve the microgrid instantaneous energy balance, the analysis of the time evolution of the waste treatment plant demand and of the generation in the existing power systems has been carried out. This has allowed the design of a suitable CSP plant with thermal storage and an electrochemical storage system for supporting the proposed microgrid. At the aim of obtaining the expected energy autonomy, a specific Energy Management Strategy, which takes into account the different dynamic performances and characteristics of the demand and the generation, has been designed. In this paper, the configuration of the proposed small scale concentrating solar power (CSP) and of its thermal energy storage, based on thermocline principle, is initially described. Finally, a simulation study of the entire power system, imposing scheduled profiles based on weather forecasts, is presented.
IEEE Transactions on Control Systems Technology, 2003
This paper presents the synthesis and practical implementation of a robust digital differentiator... more This paper presents the synthesis and practical implementation of a robust digital differentiator that provides the first and second derivative of a sampled smooth signal. The robustness of the proposed digital device, based on second-order slidingmodes (2-SMs), is analyzed with respect to measurement errors. Experimental results on an induction motor (IM) drive show that fast and accurate estimates of speed and torque can be obtained in several operating conditions by double differentiation of the encoder position measurement.
In this contribution we report on a new module prototype of high concentrator photovoltaic (HCPV)... more In this contribution we report on a new module prototype of high concentrator photovoltaic (HCPV). The optical design of the presented prototype is based on two optical elements: high quality Fresnel lenses and aluminum homogenizers, while for the realisation of the photovoltaic receiver a triple junction solar cell has been used. The whole device has been designed and developed as a cost effective product providing at the same time high value for the output power. Measurements aimed at determining electrical characteristics have been performed both on single concentrator cells and on the module realised by connecting together four single photovoltaic receivers. Thermographic measurements have been carried out in order to determine the zones where heating effects have occurred during the operating conditions. The paper purpose is to provide an overall presentation and accurate description of the final version of HCPV new module prototype that is the result of the collaboration of Italian National Institute for Astrophysics of Cagliari, Electrical and Electronic Engineering Department of University of Cagliari and Sardegna Ricerche Photovoltaic Laboratory.
The rotor speed estimation problem in electrical drives, based on shaft encoder measurements, has... more The rotor speed estimation problem in electrical drives, based on shaft encoder measurements, has been dealt with by means of a digital approximate differentiator. The proposed differentiator is based on a digital VSC which is able to perform real 2-sliding modes, so that the observer discontinuous control is confined to the second total derivative of the available encoder signal estimate, and its first derivative is then continuous. Simulation and experimental results, conducted on a field oriented induction motor drive, show the good behaviour of the proposed approximate differentiator, which has been compared with the Matlab-Simulink differentiator algorithm by using a DSP-based system.
An overview of V2G (vehicle-to-grid) technology is presented in this paper. It aims to highlight ... more An overview of V2G (vehicle-to-grid) technology is presented in this paper. It aims to highlight the main features, opportunities and requirements of V2G. Thus, after briefly resuming the most popular charging strategies for PEVs (plug-in electric vehicles), the V2G concept is introduced, especially highlighting its potentiality as a revenue opportunity for PEV owners; this is mainly due to the V2G ability to provide ancillary services, such as load leveling, regulation and reserve. Such solutions have been thoroughly investigated in the literature from both the economic and technical points of view and are here reported. In addition, V2G requirements such as mobility needs, charging stations availability and appropriate PEV aggregative architectures are properly taken into account. Finally, future developments and scenarios have also been reported.
Proceedings of Second International Conference on Power Electronics and Drive Systems, 1997
A general approach to direct torque and flux control of induction motor fed by VSI is presented i... more A general approach to direct torque and flux control of induction motor fed by VSI is presented in the paper. The inverter switching patterns are generated as a function of the reference values both of the electromagnetic torque and of the controlled flux. In particular, the proposed control algorithm is independent on which kind of flux is controlled, rotor or stator one. The results obtained by means of a real time simulation show that the proposed control strategy allows to obtain a very fast and accurate response of the drive.
ISIE '99. Proceedings of the IEEE International Symposium on Industrial Electronics (Cat. No.99TH8465)
This paper deals with the variable structure system (VSS) approach to the permanent magnet (PM) D... more This paper deals with the variable structure system (VSS) approach to the permanent magnet (PM) DC motor speed control. The aim of this treatment is that of proposing a novel scheme based on second order sliding mode control (SOSMC) technique. The main features of the proposed scheme are the robustness against heavy motor parameters variations and the avoidance of the current loop implementation, which is generally requested by traditional approaches. The precise knowledge of the motor parameters is not requested, and the insensitivity to smooth unknown load torque disturbance is obtained. Moreover, some issues associated with the practical implementation of the control scheme, mainly linked to the current ripple amplitude, are discussed, and experimental investigations are reported to show the effectiveness of the proposed approach
A novel management strategy for Electric Vehicles (EVs) storage systems is proposed in this paper... more A novel management strategy for Electric Vehicles (EVs) storage systems is proposed in this paper. It aims to enhance the Renewable Energy Sources (RES) exploitation hour by hour, but prioritizing the EV mobility requirements. A mathematical modelling of the mobility system is firstly developed in order to estimate, hour by hour, the amount of EVs available to exchange energy with
ABSTRACT A novel flux-weakening approach suitable for Surface-Mounted Permanent Magnet Synchronou... more ABSTRACT A novel flux-weakening approach suitable for Surface-Mounted Permanent Magnet Synchronous Machines (SPMs) is presented in this paper. It consists in directly synthesizing the square magnitudes of the current and voltage vectors on the basis of an accurate SPM sampled-data model and of the reference torque profile. This enables optimal and easy management of SPM operating constraints, i.e. current limitation and voltage saturation, on the basis of which the dq reference current profile can be achieved, whatever the SPM speed and Constant Power Speed Ratio (CPSR) is, i.e. finite or infinite. The effectiveness of the proposed flux-weakening approach is highlighted by both simulation and experimental results, which refer to SPMs with finite and/or infinite CPSR and driven by a predictive control algorithm.
IECON 2013 - 39th Annual Conference of the IEEE Industrial Electronics Society, 2013
ABSTRACT The continuing development and the increasing diffusion of concentrator photovoltaic (CP... more ABSTRACT The continuing development and the increasing diffusion of concentrator photovoltaic (CPV) systems highlight the lack of specific international standards in the CPV power rating and characterization field. Presently, the only reference standard for CPV cells and modules is the IEC 62108, which does not impose minimum requirements for solar trackers and simulators used in the qualification process of CPV modules. Nevertheless, the overall quality of CPV tests is strictly associated to the technical specifications of these devices. The aim of this paper is to define optical and radiometric properties of solar simulators and the pointing accuracy of solar trackers, required for testing CPV devices and rating their performance. The results of experimental analyses on real CPV systems have been reported, highlighting the criticalities of indoor and outdoor CPV characterization. Finally an outdoor light soaking test, executed under MPPT conditions, has been proposed for the qualification process of high concentrating photovoltaic devices.
... Auchen. Germany, 2004 For all these reasons the only method actually used to predict the EM1 ... more ... Auchen. Germany, 2004 For all these reasons the only method actually used to predict the EM1 behavior of a given system is the numeric simulation.[3] Y, = jY,C tan[fl(;+Ad)] ... k = 1,2 .... N -1; Y,, + jY,' tan@d) Y l + jY,, tan@d)' '%.I) 'Zk+I = yt y,,+, = y,C Y,' + jY,, tan[fl[F+Ad)] ...
One of the most recent topics in variable-structure systems theory is represented by the second-o... more One of the most recent topics in variable-structure systems theory is represented by the second-order sliding-mode control (2-SMC) methodology. This approach guarantees the same robustness and dynamic performance of traditional first-order SMC algorithms, and, at the same time, attenuates the chattering phenomenon, which is the main drawback in the actual implementation of this technique. In the present paper, a recently-proposed 2-SMC algorithm is used to synthesize a robust dc-drive control system which does not require current feedback and demands only rough information about the actual motor parameters. Stability and performance are analyzed, and an experimental comparison with a proportional-integral-based control scheme is reported.
ABSTRACT With reference to speed controlled induction motor drives, an algorithm which allows the... more ABSTRACT With reference to speed controlled induction motor drives, an algorithm which allows the on-line estimation either of the speed and one motor parameter or, alternatively, of two motor parameters, is presented in the paper. The results obtained by simulation fully confirm the validity of the proposed algorithm. Finally, the problems arising from the implementation of the proposed algorithm on a DSP-based control hardware are analysed
ABSTRACT An optimal energy storage system (ESS) management procedure devoted to full renewable en... more ABSTRACT An optimal energy storage system (ESS) management procedure devoted to full renewable energy sources (RESs) exploitation is presented in this paper. It consists of an appropriate scheduling procedure and a real-time control strategy, which both aim to increase the RES penetration level as much as possible. In particular, the one-day-ahead scheduling procedure synthesizes the combined RES-ESS energy production profile with the aim of minimizing the RES energy production curtailments by means of ESS energy buffering. The real-time control strategy is developed in order to track the scheduled profile as well as possible by mitigating forecasting errors, thus improving RES reliability. The worth and effectiveness of the proposed management procedure is verified through a wide simulation study, which is carried out by means of the Matlab software package.
ABSTRACT An improved control algorithm for a multilevel DTC drive is proposed in the present pape... more ABSTRACT An improved control algorithm for a multilevel DTC drive is proposed in the present paper. It allows avoidance of the demagnetisation phenomena at zero speed and reduction of the torque ripple without increasing the switching frequency. In particular, the reference torque time derivative is used with the aim of optimising the NPC converter voltage selection criteria, during torque and load variations. Results of extensive simulations are presented and discussed to prove the effectiveness of the proposed multilevel DTC drive
The integration of small scale concentrating solar power (CSP) in an industrial district, in orde... more The integration of small scale concentrating solar power (CSP) in an industrial district, in order to develop a microgrid fully supplied by renewable energy sources, is presented in this paper. The plant aims to assess in real operating conditions, the performance, the effectiveness and the reliability of small-scale concentrating solar power technologies in the field of distributed generation. In particular, the potentiality of small scale CSP with thermal storage to supply dispatchable electricity to an industrial microgrid will be investigated. The microgrid will be realized in the municipal waste treatment plant of the Industrial Consortium of Villacidro, in southern Sardinia (Italy), which already includes a biogas power plant. In order to achieve the microgrid instantaneous energy balance, the analysis of the time evolution of the waste treatment plant demand and of the generation in the existing power systems has been carried out. This has allowed the design of a suitable CSP plant with thermal storage and an electrochemical storage system for supporting the proposed microgrid. At the aim of obtaining the expected energy autonomy, a specific Energy Management Strategy, which takes into account the different dynamic performances and characteristics of the demand and the generation, has been designed. In this paper, the configuration of the proposed small scale concentrating solar power (CSP) and of its thermal energy storage, based on thermocline principle, is initially described. Finally, a simulation study of the entire power system, imposing scheduled profiles based on weather forecasts, is presented.
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Papers by A. Damiano