440 research outputs found
Novel single-phase five-level VIENNA-type rectifier with model predictive current control
A novel single-phase five-level active rectifier based
on the VIENNA-type rectifier with model predictive current
control is presented. The proposed topology operates in
unidirectional mode, imposing a sinusoidal grid-side current with
unitary power factor. A unidirectional electric vehicle battery
charger is the target application in which the proposed rectifier is
used; however, it can also be used as an active rectifier for other
purposes aiming to improve the efficiency of ac-to-dc
rectification. The model predictive current control is used to
select the active rectifier state during each sampling period,
trying to minimize the grid current error and obtain low total
harmonic distortion. The suitability and performance of the
proposed topology of active rectifier, as well as the principle of
operation and the digital control algorithm, are evaluated
through simulation and experimental results.This work has been supported by COMPETE: POCI-01-
0145–FEDER–007043 and FCT – Fundação para a Ciência e
Tecnologia within the Project Scope: UID/CEC/00319/2013.
This work is financed by the ERDF – European Regional
Development Fund through the Operational Programme for
Competitiveness and Internationalisation – COMPETE 2020
Programme, and by National Funds through the Portuguese
funding agency, FCT – Fundação para a Ciência e a Tecnologia, within project SAICTPAC/0004/2015 – POCI –
01–0145–FEDER–016434.info:eu-repo/semantics/publishedVersio
Model predictive control of a single-phase five-level VIENNA rectifier
Power converters and control strategies are very vital for the increasing sustainability of the power grid targeting smart grids. In these circumstances, it is proposed a novel single-phase five-level (SP5L) VIENNA rectifier digitally controlled by a model predictive control (MPC) with fixed switching frequency, which can be useful for a variety of applications with a robust current tracking. The proposed SP5L VIENNA rectifier is an advancement of the classical three-level VIENNA rectifier, also contributing to preserve power quality, and exhibiting the advantage of operating with more voltage levels at the expense of few additional switching devices. The proposed topology is introduced and correlated with the classical solutions of active rectifiers. The operation principle is introduced and used to describe the MPC, which is given in detail, as well as the necessary modulation strategy. The results were obtained for a set of various operating conditions, both in terms of reference of current and grid-side voltage, as well as in steady-state and transient-state, proving the benefits of the proposed SP5L VIENNA rectifier and the accurate and precise use of the MPC to control the grid-side current.This work has been supported by FCT -Fundacao para a Ciencia e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020. This work has been supported by the FCT Project newERA4GRIDs PTDC/EEI-EEE/30283/2017, and by the FCT Project DAIPESEV PTDC/EEI-EEE/30382/2017. Tiago Sousa is supported by the doctoral scholarship SFRH/BD/134353/2017 granted by FCT
Model predictive current control of a proposed single-switch three-level active rectifier applied to EV battery chargers
This paper presents a model predictive current
control applied to a proposed new topology of single-switch
three-level (SSTL) active rectifier, which is exemplified in an
application of single-phase battery charger for electric vehicles
(EVs). During each sampling period, this current control scheme
selects the state of the SSTL active rectifier that minimizes the
error between the grid current and its reference. Using this
strategy it is possible to obtain sinusoidal grid currents with low
total harmonic distortion and unitary power factor, which is one
of the main requirements for EVs chargers. The paper presents
in detail the principle of operation of the SSTL active rectifier,
the digital control algorithm and the EV battery charger (where
is incorporated the SSTL active rectifier) that was used in the
experimental verification. The obtained experimental results
confirm the correct application of the model predictive current
control applied to the proposed SSTL active rectifier.This work was supported in part by the FCT–Fundação para a Ciência e Tecnologia in the scope of the project: PEst UID/CEC/00319/2013. VÃtor Monteiro was supported by the scholarship SFRH/BD/80155/2011 granted by the FCT agency
A novel fixed switching frequency control strategy applied to an improved five-level active rectifier
A novel fixed switching frequency control
strategy applied to an improved five-level active rectifier
(iFLAR) is proposed. The operation with fixed switching
frequency represents a powerful advantage, since the range of
the produced harmonics is well identified, and it is possible to
design passive filters to mitigate such harmonics. The
experimental validation shows that the control strategy allows
attaining an ac-side current with reduced total harmonic
distortion and high power factor, which is an attractive
influence for grid-connected electrical appliances. This
contribution is even more relevant with the new paradigm of
smart grids where higher levels of power quality are required.
A theoretical analysis of the control strategy and the details of
its implementation in a digital signal processor are presented.
The control scheme and the developed iFLAR were
experimentally confirmed using a laboratorial prototype,
showing its benefits in terms of accuracy, reduced total
harmonic distortion and high power factor.This work has been supported by COMPETE: POCI-010145-FEDER-007043 and FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013. This work is financed by the ERDF – European Regional Development Fund through the Operational Programme for Competitiveness and Internationalisation – COMPETE 2020 Programme, and by National Funds through the Portuguese funding agency, FCT – Fundação para a Ciência e a Tecnologia, within project SAICTPAC/0004/2015 – POCI – 01–0145–FEDER–016434. Mr. Tiago Sousa is supported by the doctoral scholarship SFRH/BD/134353/2017 granted by the Portuguese FCT agency. This work is part of the FCT project 0302836 NORTE-01-0145-FEDER-030283.info:eu-repo/semantics/publishedVersio
A novel single-phase bidirectional nine-level converter employing four quadrant switches
A novel bidirectional ac-dc multilevel converter
based on four quadrant switches is proposed. This new
converter can establish nine voltage levels downstream the
coupling filter used to interface with the power grid, and,
comparing with conventional two- or three-level converters, it
operates with improved ac-side current, both for operation as
active rectifier (on-grid), grid-tied inverter (on-grid) or voltage
inverter (off-grid). A detailed description of the converter is
exhibited, highlighting its main advantages according to the
applications where it can be employed in smart grid scenarios.
In order to confirm its viability, a considerable set of results is
presented and discussed, establishing an overall comparison
with conventional converters. Moreover, the proposed
converter is validated operating as active rectifier, as grid-tied
inverter, and as voltage inverter, controlled in closed-loop by
current or voltage. The details of the proposed power converter
hardware and the implementation of the digital algorithm,
based on a fixed switching frequency structure, are clarified and
discussed throughout the paper.This work has been supported by COMPETE: POCI-010145-FEDER-007043 and FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013. This work is financed by the ERDF – European Regional Development Fund through the Operational Programme for Competitiveness and Internationalisation – COMPETE 2020 Programme, and by National Funds through the Portuguese funding agency FCT within project SAICTPAC/0004/2015 – POCI – 01–0145–FEDER–016434. Mr. Tiago Sousa is supported by the doctoral scholarship SFRH/BD/134353/2017 granted by of the FCT project 0302836 NORTE-01-0145-FEDER-030283.info:eu-repo/semantics/publishedVersio
A novel control strategy based on predictive control for a bidirectional interleaved three-phase converter
An experimental confirmation of predictive control
applied to a bidirectional interleaved three-phase (BIT) converter
is presented. The BIT converter is a powerful solution for
numerous applications, mainly, renewables interface, motor
drivers, active rectifiers, and active power filters. However, a
precise and robust digital control strategy is required,
maintaining a low computational effort. In this paper, a
predictive control based on continuous control set is proposed as
a new control scheme for the BIT converter, permitting the
control of the ac side current with fixed switching frequency and
with a faster response. The predictive control scheme applied to
the BIT converter is defined along the paper, evidencing in detail
the digital employment aspects according to the discrete-time
model of the BIT converter. An explicit experimental validation
under realistic operating conditions is presented using a
developed laboratorial prototype, highlighting the convenience of
the control applied to the BIT converter.This work has been supported by FCT – Fundação para a
Ciência e Tecnologia in the scope of the project: PEstUID/CEC/00319/2013.
This work has been supported by
COMPETE: POCI-01-0145-FEDER-007043 and FCT –
Fundação para a Ciência e Tecnologia within the Project
Scope: UID/CEC/00319/2013. This work is financed by the
ERDF – European Regional Development Fund through the
Operational Programme for Competitiveness and
Internationalisation < COMPETE 2020 Programme, and by
National Funds through the Portuguese funding agency, FCT <
Fundação para a Ciência e a Tecnologia, within project
SAICTPAC/0004/2015< POCI< 01<0145<FEDER<016434. Mr.
Tiago Sousa is supported by the doctoral scholarship
SFRH/BD/134353/2017 granted by the Portuguese FCT
agency.info:eu-repo/semantics/publishedVersio
Model predictive control applied to an improved five-level bidirectional converter
This paper presents an improved five level bidirectional converter (iFBC) controlled by finite control set model predictive control (FCS-MPC). This control strategy consists in using the discrete time nature of the iFBC to define its state in each sampling interval. Using FCS-MPC the switching frequency is not constant; however, it is suitable to follow the current reference with low total harmonic distortion (THD). The iFBC prototype that was specially developed for obtaining experimental results is described in detail along the paper, as well as its principle of operation, power theory, and current control strategy. The iFBC was experimentally validated connected to the power grid through a second order LfCf passive filter, operating as an active rectifier and as a grid tie inverter. For both operation modes, the experimental results confirm the good performance (in terms of efficiency, low current THD and controlled output voltage) of the iFBC controlled by FCS-MPC.FC
A novel multilevel interleaved-based PFC rectifier with modular DC interfaces
As it has been recognized, mainly over the last decades, PFC rectifiers are more and more fundamental and are increasingly present in several applications in the perspective of limiting power quality problems. In line with this reality, this paper proposes a novel topology of single-phase PFC rectifier. On the AC-side, the proposed PFC rectifier operates with sinusoidal current in phase with the voltage, but, additionally, it presents these very important advantages: Multilevel voltage operation; Interleaved-based current control; Modular design, allowing to establish n DC interfaces on the DC-side. The proposed PFC rectifier is comprehensively detailed, and the validation is carried out with a configuration that allows to have two independent DC interfaces, resulting in an operation with five different voltage levels, and in a current control with a ripple with a frequency that corresponds to four times the value of the switching frequency of each switching device. The validation was carried out addressing the operation of the proposed PFC rectifier in steady-state and transient-state.This work has been supported by FCT - Fundacao para a Ciencia e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020. This work has been supported by the FCT Project newERA4GRIDs PTDC/EEI-EEE/30283/2017
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