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Migliazza Giovanni - One of the best experts on this subject based on the ideXlab platform.
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Studio di nuove soluzioni di Inverter a corrente impressa per sorgenti energetiche rinnovabili e per azionamenti elettrici in ambito aerospaziale
Università degli studi di Modena e Reggio Emilia, 2020Co-Authors: Migliazza GiovanniAbstract:In questo lavoro di tesi è stata analizzata una particolare architettura di convertitore elettronico di potenza DC/AC denominata CSI (“Current Source inverter”). Storicamente, questa topologia è stata largamente impiegata per l’azionamento di macchine elettriche in media tensione. Il CSI, rispetto ai più diffusi Voltage Source Inverter (VSI) è caratterizzato da maggiori perdite di conduzione dei propri transistor ma è in grado di garantire un’affidabilità più elevata, siccome il corto-circuito di un qualunque mezzo-ponte (gamba dell’inverter) non determina una rottura (come nelle comuni architetture VSI), ma bensì è una normale condizione operativa all’interno di un periodo di commutazione della modulazione PWM. Una peculiarità importante di questa topologia è il suo funzionamento intrinseco come step-up nel caso la sorgente in ingresso al convertitore sia costituita da una sorgente di tensione continua seguita da un induttore. In questo lavoro si sono investigate modifiche topologiche rispetto all’architettura classica del CSI, nuove strategie di controllo e modulazioni PWM al fine di incrementare l’efficienza di conversione, ridurre il contenuto armonico indesiderato delle proprie correnti di uscita e limitare le correnti di modo comune. Cercando cosi, di rendere la topologia competitiva in applicazioni Industriali. Differenti soluzioni topologiche e di controllo del CSI sono state studiate per due differenti applicazioni: convertitori DC/AC grid-connected senza isolamento galvanico per sistemi fotovoltaici e per azionamenti elettrici per applicazioni aerospaziali. Nell’ambito dei convertitori DC/AC grid-connected sono state proposte soluzioni sia per sistemi trifase, sia per sistemi monofase. In particolare grazie all’aggiunta di uno o più transistor e a modulazioni PWM dedicate è stato possibile ridurre le perdite di conduzione, il contenuto armonico delle correnti iniettate in rete e la corrente di dispersione verso terra. Nella seconda applicazione come azionamento elettrico, si è investigato l’impatto della topologia nel mondo aerospaziale, proponendo una nuova strategia di controllo che permette di controllare la macchina elettrica unicamente attraverso un’architettura tradizionale CSI con sorgente di tensione continua e induttore serie, senza l’ausilio di un ulteriore convertitore DC-DC che regola la corrente in ingresso al CSI. Sfruttando la caratteristica intrinseca di innalzamento della tensione d’uscita dell’azionamento, sono stati progettati dei motori elettrici che potendo lavorare a tensioni più elevate e con basso contenuto armonico grazie al filtro d’uscita intrinseco del CSI, è possibile realizzare delle macchine con densità di potenza elevata, aspetto molto interessante in ambito aerospaziale.In this thesis work, a particular DC / AC power converter architecture called CSI ("Current Source inverter") was analyzed. Historically, this topology has been widely used for driving medium voltage electrical machines. The CSI, compared to the more widespread Voltage Source Inverter (VSI) is characterized by higher semiconductor conduction losses but is able to guarantee a higher reliability as the short-circuit of any half-bridge (inverter leg) does not cause a break (as in VSI architectures), but rather it is a normal operating condition within the pattern of PWM modulation. An important peculiarity of this topology is its intrinsic operation as voltage step-up when the input source of the converter consists of a DC voltage with an inductor in series. In this work, some topological variations respect to the classical CSI architecture were investigated along with new control strategies and Space Vector Modulation(SVM) in order to increase the conversion efficiency, to reduce the undesired harmonic component of output currents, and to mitigate the common mode current. Different CSI topologies and control strategies have been designed for two different applications: DC / AC grid-connected converters without galvanic isolation for photovoltaic applications and electric drives for Aerospace applications. In Grid-connected applications, DC / AC converter solutions have been proposed for three-phase and single-phase systems. In particular, thanks to the addition of one or more transistors and dedicated SVM, it was possible to reduce conduction losses, the harmonic component in the injected currents into the grid and the ground leakage current. In the second application, the impact of the CSI topology in the Aerospace Environment was investigated. The proposed control strategy allows to control the electric machine using only the traditional CSI architecture with a DC Voltage source and with an inductor in series, without the aid of an additional DC-DC converter that regulates the input current of the CSI. Taking advantage of the intrinsic step-up voltage characteristic and very low high frequency harmonic content of the output phase voltages (thanks to the intrinsic CSI output filter), electric motors can be designed for higher voltages allowing higher power density, very interesting aspect in the Aerospace field
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Studio di nuove soluzioni di Inverter a corrente impressa per sorgenti energetiche rinnovabili e per azionamenti elettrici in ambito aerospaziale
Università degli studi di Modena e Reggio Emilia, 2020Co-Authors: Migliazza GiovanniAbstract:In questo lavoro di tesi \ue8 stata analizzata una particolare architettura di convertitore elettronico di potenza DC/AC denominata CSI (\u201cCurrent Source inverter\u201d). Storicamente, questa topologia \ue8 stata largamente impiegata per l\u2019azionamento di macchine elettriche in media tensione. Il CSI, rispetto ai pi\uf9 diffusi Voltage Source Inverter (VSI) \ue8 caratterizzato da maggiori perdite di conduzione dei propri transistor ma \ue8 in grado di garantire un\u2019affidabilit\ue0 pi\uf9 elevata, siccome il corto-circuito di un qualunque mezzo-ponte (gamba dell\u2019inverter) non determina una rottura (come nelle comuni architetture VSI), ma bens\uec \ue8 una normale condizione operativa all\u2019interno di un periodo di commutazione della modulazione PWM. Una peculiarit\ue0 importante di questa topologia \ue8 il suo funzionamento intrinseco come step-up nel caso la sorgente in ingresso al convertitore sia costituita da una sorgente di tensione continua seguita da un induttore. In questo lavoro si sono investigate modifiche topologiche rispetto all\u2019architettura classica del CSI, nuove strategie di controllo e modulazioni PWM al fine di incrementare l\u2019efficienza di conversione, ridurre il contenuto armonico indesiderato delle proprie correnti di uscita e limitare le correnti di modo comune. Cercando cosi, di rendere la topologia competitiva in applicazioni Industriali. Differenti soluzioni topologiche e di controllo del CSI sono state studiate per due differenti applicazioni: convertitori DC/AC grid-connected senza isolamento galvanico per sistemi fotovoltaici e per azionamenti elettrici per applicazioni aerospaziali. Nell\u2019ambito dei convertitori DC/AC grid-connected sono state proposte soluzioni sia per sistemi trifase, sia per sistemi monofase. In particolare grazie all\u2019aggiunta di uno o pi\uf9 transistor e a modulazioni PWM dedicate \ue8 stato possibile ridurre le perdite di conduzione, il contenuto armonico delle correnti iniettate in rete e la corrente di dispersione verso terra. Nella seconda applicazione come azionamento elettrico, si \ue8 investigato l\u2019impatto della topologia nel mondo aerospaziale, proponendo una nuova strategia di controllo che permette di controllare la macchina elettrica unicamente attraverso un\u2019architettura tradizionale CSI con sorgente di tensione continua e induttore serie, senza l\u2019ausilio di un ulteriore convertitore DC-DC che regola la corrente in ingresso al CSI. Sfruttando la caratteristica intrinseca di innalzamento della tensione d\u2019uscita dell\u2019azionamento, sono stati progettati dei motori elettrici che potendo lavorare a tensioni pi\uf9 elevate e con basso contenuto armonico grazie al filtro d\u2019uscita intrinseco del CSI, \ue8 possibile realizzare delle macchine con densit\ue0 di potenza elevata, aspetto molto interessante in ambito aerospaziale.In this thesis work, a particular DC / AC power converter architecture called CSI ("Current Source inverter") was analyzed. Historically, this topology has been widely used for driving medium voltage electrical machines. The CSI, compared to the more widespread Voltage Source Inverter (VSI) is characterized by higher semiconductor conduction losses but is able to guarantee a higher reliability as the short-circuit of any half-bridge (inverter leg) does not cause a break (as in VSI architectures), but rather it is a normal operating condition within the pattern of PWM modulation. An important peculiarity of this topology is its intrinsic operation as voltage step-up when the input source of the converter consists of a DC voltage with an inductor in series. In this work, some topological variations respect to the classical CSI architecture were investigated along with new control strategies and Space Vector Modulation(SVM) in order to increase the conversion efficiency, to reduce the undesired harmonic component of output currents, and to mitigate the common mode current. Different CSI topologies and control strategies have been designed for two different applications: DC / AC grid-connected converters without galvanic isolation for photovoltaic applications and electric drives for Aerospace applications. In Grid-connected applications, DC / AC converter solutions have been proposed for three-phase and single-phase systems. In particular, thanks to the addition of one or more transistors and dedicated SVM, it was possible to reduce conduction losses, the harmonic component in the injected currents into the grid and the ground leakage current. In the second application, the impact of the CSI topology in the Aerospace Environment was investigated. The proposed control strategy allows to control the electric machine using only the traditional CSI architecture with a DC Voltage source and with an inductor in series, without the aid of an additional DC-DC converter that regulates the input current of the CSI. Taking advantage of the intrinsic step-up voltage characteristic and very low high frequency harmonic content of the output phase voltages (thanks to the intrinsic CSI output filter), electric motors can be designed for higher voltages allowing higher power density, very interesting aspect in the Aerospace field
Fengming Li - One of the best experts on this subject based on the ideXlab platform.
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Recent advances in micro-vibration isolation
Mechanical Systems and Signal Processing, 2015Co-Authors: Chunchuan Liu, Xingjian Jing, Steve Daley, Fengming LiAbstract:Micro-vibration caused by disturbance sources onboard spacecraft can severely degrade the working Environment of sensitive payloads. Some notable vibration control methods have been developed particularly for the suppression or isolation of micro-vibration over recent decades. Usually, passive isolation techniques are deployed in Aerospace engineering. Active isolators, however, are often proposed to deal with the low frequency vibration that is common in spacecraft. Active/passive hybrid isolation has also been effectively used in some spacecraft structures for a number of years. In semi-active isolation systems, the inherent structural performance can be adjusted to deal with variation in the Aerospace Environment. This latter approach is potentially one of the most practical isolation techniques for micro-vibration isolation tasks. Some emerging advanced vibration isolation methods that exploit the benefits of nonlinearity have also been reported in the literature. This represents an interesting and highly promising approach for solving some challenging problems in the area. This paper serves as a state-of-the-art review of the vibration isolation theory and/or methods which were developed, mainly over the last decade, specifically for or potentially could be used for, micro-vibration control.
Chunchuan Liu - One of the best experts on this subject based on the ideXlab platform.
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Recent advances in micro-vibration isolation
Mechanical Systems and Signal Processing, 2015Co-Authors: Chunchuan Liu, Xingjian Jing, Steve Daley, Fengming LiAbstract:Micro-vibration caused by disturbance sources onboard spacecraft can severely degrade the working Environment of sensitive payloads. Some notable vibration control methods have been developed particularly for the suppression or isolation of micro-vibration over recent decades. Usually, passive isolation techniques are deployed in Aerospace engineering. Active isolators, however, are often proposed to deal with the low frequency vibration that is common in spacecraft. Active/passive hybrid isolation has also been effectively used in some spacecraft structures for a number of years. In semi-active isolation systems, the inherent structural performance can be adjusted to deal with variation in the Aerospace Environment. This latter approach is potentially one of the most practical isolation techniques for micro-vibration isolation tasks. Some emerging advanced vibration isolation methods that exploit the benefits of nonlinearity have also been reported in the literature. This represents an interesting and highly promising approach for solving some challenging problems in the area. This paper serves as a state-of-the-art review of the vibration isolation theory and/or methods which were developed, mainly over the last decade, specifically for or potentially could be used for, micro-vibration control.
Xingjian Jing - One of the best experts on this subject based on the ideXlab platform.
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Recent advances in micro-vibration isolation
Mechanical Systems and Signal Processing, 2015Co-Authors: Chunchuan Liu, Xingjian Jing, Steve Daley, Fengming LiAbstract:Micro-vibration caused by disturbance sources onboard spacecraft can severely degrade the working Environment of sensitive payloads. Some notable vibration control methods have been developed particularly for the suppression or isolation of micro-vibration over recent decades. Usually, passive isolation techniques are deployed in Aerospace engineering. Active isolators, however, are often proposed to deal with the low frequency vibration that is common in spacecraft. Active/passive hybrid isolation has also been effectively used in some spacecraft structures for a number of years. In semi-active isolation systems, the inherent structural performance can be adjusted to deal with variation in the Aerospace Environment. This latter approach is potentially one of the most practical isolation techniques for micro-vibration isolation tasks. Some emerging advanced vibration isolation methods that exploit the benefits of nonlinearity have also been reported in the literature. This represents an interesting and highly promising approach for solving some challenging problems in the area. This paper serves as a state-of-the-art review of the vibration isolation theory and/or methods which were developed, mainly over the last decade, specifically for or potentially could be used for, micro-vibration control.
Steve Daley - One of the best experts on this subject based on the ideXlab platform.
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Recent advances in micro-vibration isolation
Mechanical Systems and Signal Processing, 2015Co-Authors: Chunchuan Liu, Xingjian Jing, Steve Daley, Fengming LiAbstract:Micro-vibration caused by disturbance sources onboard spacecraft can severely degrade the working Environment of sensitive payloads. Some notable vibration control methods have been developed particularly for the suppression or isolation of micro-vibration over recent decades. Usually, passive isolation techniques are deployed in Aerospace engineering. Active isolators, however, are often proposed to deal with the low frequency vibration that is common in spacecraft. Active/passive hybrid isolation has also been effectively used in some spacecraft structures for a number of years. In semi-active isolation systems, the inherent structural performance can be adjusted to deal with variation in the Aerospace Environment. This latter approach is potentially one of the most practical isolation techniques for micro-vibration isolation tasks. Some emerging advanced vibration isolation methods that exploit the benefits of nonlinearity have also been reported in the literature. This represents an interesting and highly promising approach for solving some challenging problems in the area. This paper serves as a state-of-the-art review of the vibration isolation theory and/or methods which were developed, mainly over the last decade, specifically for or potentially could be used for, micro-vibration control.