The Experts below are selected from a list of 18648 Experts worldwide ranked by ideXlab platform
L G Franquelo - One of the best experts on this subject based on the ideXlab platform.
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dc link voltage balancing strategy based on optimal Switching Sequence model predictive control for single phase h npc converters
IEEE Transactions on Industrial Electronics, 2020Co-Authors: Sergio Vazquez, Pablo Acuna, Ricardo P Aguilera, Josep Pou, Jose I Leon, L G FranqueloAbstract:In this article, a model predictive control (MPC) strategy based on the optimal Switching Sequence (OSS) concept for a single-phase grid-connected H-bridge neutral-point-clamped (H-NPC) power converter is presented. The proposed OSS-MPC algorithm considers both the grid current tracking error and the dc-link capacitor voltage balance. Special emphasis is placed on the power converter control region in order to design suitable Switching Sequence candidates for this multiobjective control problem. Additionally, based on an analysis of the weighting factor effect over closed-loop performance, it is possible to demonstrate that this controller parameter is relatively easy to adjust. In fact, the weighting factor only affects the peak current during transients, with no effect over the steady-state performance. As a result, the proposed OSS-MPC provides a fast closed-loop dynamic to the H-NPC converter, which operates with a fixed Switching frequency at all times. This predictive control strategy is experimentally validated in a 3.5-kVA laboratory setup.
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predictive optimal Switching Sequence direct power control for grid connected power converters
IEEE Transactions on Industrial Electronics, 2015Co-Authors: Sergio Vazquez, Ricardo P Aguilera, Jose I Leon, Abraham Marquez, Daniel E Quevedo, L G FranqueloAbstract:Grid-connected power converters play a key role in several applications such as the integration of renewable energy sources and motor drives. For this reason, the development of high performance control strategies for this particular class of power converters has increasingly attracted the interest of both academic and industry researchers. This paper presents the predictive optimal Switching Sequence (OSS) direct power control (DPC) (OSS-DPC) algorithm for grid-connected converters. The OSS-DPC method belongs to the predictive-DPC family and provides the desired power references by calculating globally OSSs. To address computational and implementation issues, an efficient control algorithm, named reduced OSS-DPC, is introduced. The implementation of the proposed control strategy in a standard DSP is evaluated on a two-level power converter prototype working as a STATCOM. Experimental results show the algorithm's potential to provide high performance during both transient and steady states.
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multidimensional modulation technique for cascaded multilevel converters
IEEE Transactions on Industrial Electronics, 2009Co-Authors: Jose I Leon, Sergio Vazquez, L G Franquelo, Samir Kouro, R Portillo, J M Carrasco, Jose RodriguezAbstract:Multilevel cascaded H-bridge converters have found industrial application in the medium-voltage high-power range. In this paper, a generalized modulation technique for this type of converter based on a multidimensional control region is presented. Using the multidimensional control region, it is shown that all previous modulation techniques are particularized versions of the proposed method. Several possible solutions to develop a specific implementation of the modulation method are addressed in order to show the potential possibilities and the flexibility of the proposed technique. In addition, a feedforward version of this technique is also introduced to determine the Switching Sequence and the Switching times, avoiding low harmonic distortion with unbalanced dc voltages. Experimental results are shown in order to validate the proposed concepts.
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effective algorithm for multilevel converters with very low computational cost
Electronics Letters, 2002Co-Authors: M M Prats, Juan Manuel Campos Carrasco, L G FranqueloAbstract:An effective and fast modulation algorithm for high power voltage source multilevel converters is presented. This approach drastically reduces the computational load maintained, permitting the on-line computation of the Switching Sequence and the on-state durations of the respective Switching state vectors. It has been satisfactorily implemented in very low-cost microcontrollers.
Frede Blaabjerg - One of the best experts on this subject based on the ideXlab platform.
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model predictive control of lc filtered voltage source inverters with optimal Switching Sequence
IEEE Transactions on Power Electronics, 2021Co-Authors: Changming Zheng, Tomislav Dragicevic, Zhenbin Zhang, Jose Rodriguez, Frede BlaabjergAbstract:Voltage source inverters with output LC filter enable a sinusoidal output voltage with low harmonics, suitable for islanded ac microgrid or uninterruptible power supply applications. Conventional finite-set model predictive voltage control (MPVC) applies only a single Switching vector per control period, leading to a variable Switching frequency and significant output ripple. This article resolves these issues by proposing an improved MPVC with optimal Switching Sequence (OSS-MPVC). First, an improved vector Switching Sequence is defined, aiming to reduce the output-voltage ripple with a constant Switching frequency. Then, to tackle the difficulty in extending the OSS to high-order systems due to the coupling effect of the output filter, a generalized “one-step estimation” solution is proposed, which directly associates the control-variable gradients with the vector Switching Sequence. To further enhance the output-voltage tracking accuracy, intersample dynamics are taken into account in the cost function. The control delay and dead-time compensation are also considered. Simulations and experimental results verify the feasibility of the proposed method.
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multi objective modulated model predictive control of stand alone voltage source converters
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2020Co-Authors: Branko Majmunovic, Tomislav Dragicevic, Frede BlaabjergAbstract:This paper introduces a novel model predictive control (MPC) strategy for stand-alone voltage source converters (VSCs) with constant Switching frequency. Multiple control targets are incorporated in a single cost function. This allows fulfilling all the requirements for an uninterruptible power supply (UPS) inverter in terms of fast dynamic response, elimination of steady-state error, and harmonic compensation capability. The control output vector is determined as an analytical solution that corresponds to the minimum value of the cost function. The space vector modulation (SVM) is then used to synthesize the corresponding Switching Sequence. Therefore, this control strategy is equivalent to the linear state feedback control, which allows the usage of linear theory for tuning the parameters. The superior characteristics of this control strategy compared to cascaded linear control and finite control set MPC are, finally, demonstrated experimentally.
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method to minimize the low frequency neutral point voltage oscillations with time offset injection for neutral point clamped inverters
IEEE Transactions on Industry Applications, 2015Co-Authors: Uimin Choi, Frede BlaabjergAbstract:This paper proposes a method to reduce the low-frequency neutral-point voltage oscillations. The neutral-point voltage oscillations are considerably reduced by adding a time offset to the three-phase turn-on times. The proper time offset is simply calculated considering the phase currents and dwell time of small- and medium-voltage vectors. However, if the power factor is lower, there is a limitation to eliminate neutral-point oscillations. In this case, the proposed method can be improved by changing the Switching Sequence properly. Additionally, a method for neutral-point voltage balancing is also proposed. The change in Switching frequency by the proposed method and its effects on the outputs are negligible. Simulation and experimental results verify the validity and feasibility of the proposed strategy.
Sergio Vazquez - One of the best experts on this subject based on the ideXlab platform.
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dc link voltage balancing strategy based on optimal Switching Sequence model predictive control for single phase h npc converters
IEEE Transactions on Industrial Electronics, 2020Co-Authors: Sergio Vazquez, Pablo Acuna, Ricardo P Aguilera, Josep Pou, Jose I Leon, L G FranqueloAbstract:In this article, a model predictive control (MPC) strategy based on the optimal Switching Sequence (OSS) concept for a single-phase grid-connected H-bridge neutral-point-clamped (H-NPC) power converter is presented. The proposed OSS-MPC algorithm considers both the grid current tracking error and the dc-link capacitor voltage balance. Special emphasis is placed on the power converter control region in order to design suitable Switching Sequence candidates for this multiobjective control problem. Additionally, based on an analysis of the weighting factor effect over closed-loop performance, it is possible to demonstrate that this controller parameter is relatively easy to adjust. In fact, the weighting factor only affects the peak current during transients, with no effect over the steady-state performance. As a result, the proposed OSS-MPC provides a fast closed-loop dynamic to the H-NPC converter, which operates with a fixed Switching frequency at all times. This predictive control strategy is experimentally validated in a 3.5-kVA laboratory setup.
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predictive optimal Switching Sequence direct power control for grid connected power converters
IEEE Transactions on Industrial Electronics, 2015Co-Authors: Sergio Vazquez, Ricardo P Aguilera, Jose I Leon, Abraham Marquez, Daniel E Quevedo, L G FranqueloAbstract:Grid-connected power converters play a key role in several applications such as the integration of renewable energy sources and motor drives. For this reason, the development of high performance control strategies for this particular class of power converters has increasingly attracted the interest of both academic and industry researchers. This paper presents the predictive optimal Switching Sequence (OSS) direct power control (DPC) (OSS-DPC) algorithm for grid-connected converters. The OSS-DPC method belongs to the predictive-DPC family and provides the desired power references by calculating globally OSSs. To address computational and implementation issues, an efficient control algorithm, named reduced OSS-DPC, is introduced. The implementation of the proposed control strategy in a standard DSP is evaluated on a two-level power converter prototype working as a STATCOM. Experimental results show the algorithm's potential to provide high performance during both transient and steady states.
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multidimensional modulation technique for cascaded multilevel converters
IEEE Transactions on Industrial Electronics, 2009Co-Authors: Jose I Leon, Sergio Vazquez, L G Franquelo, Samir Kouro, R Portillo, J M Carrasco, Jose RodriguezAbstract:Multilevel cascaded H-bridge converters have found industrial application in the medium-voltage high-power range. In this paper, a generalized modulation technique for this type of converter based on a multidimensional control region is presented. Using the multidimensional control region, it is shown that all previous modulation techniques are particularized versions of the proposed method. Several possible solutions to develop a specific implementation of the modulation method are addressed in order to show the potential possibilities and the flexibility of the proposed technique. In addition, a feedforward version of this technique is also introduced to determine the Switching Sequence and the Switching times, avoiding low harmonic distortion with unbalanced dc voltages. Experimental results are shown in order to validate the proposed concepts.
Hideaki Fujita - One of the best experts on this subject based on the ideXlab platform.
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a single phase active filter using an h bridge pwm converter with a sampling frequency quadruple of the Switching frequency
IEEE Transactions on Power Electronics, 2009Co-Authors: Hideaki FujitaAbstract:This paper presents a digital current regulator for H-bridge pulsewidth modulation (PWM) converters, whose sampling frequency equals quadruple of the Switching frequency. The current regulator detects the ac current and manipulates the voltage reference not only at the upper and lower peaks of the PWM triangle carrier but also at its zero crossings. This paper theoretically discusses the Switching Sequence of the H-bridge PWM converter, and reveals the amount of the voltage error and the condition where the voltage error occurs. A modified deadbeat current regulator is proposed to suppress the current oscillation induced by the voltage error, based on the theoretical analysis. Experimental results are shown to verify the control performance of the proposed current regulator. Moreover, a proposed current regulator is applied to a single-phase active power filter to demonstrate the effectiveness in harmonic compensation.
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a single phase active filter using an h bridge pwm converter with a sampling frequency quadruple of the Switching frequency
Power Electronics Specialists Conference, 2008Co-Authors: Hideaki FujitaAbstract:This paper presents a digital current regulator for an H-bridge PWM converter, having a sampling frequency equal to quadruple of the Switching frequency. The current regulator detects the current and manipulates the voltage reference not only at the upper and lower peaks of the PWM triangle carrier but also at its zero crossings. This paper theoretically discusses the Switching Sequence of the H-bridge PWM converter and reveals the amount of the voltage error and the condition where the voltage error occurs. A modified deadbeat current regulator is proposed to suppress the current oscillation induced by the voltage error, based on the theoretical analysis. Experimental results are shown to verify the control performance of the proposed current regulator. Moreover, a proposed current regulator is applied to a single-phase active power filter to demonstrate the effectiveness in harmonic compensation.
Bin Wu - One of the best experts on this subject based on the ideXlab platform.
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a novel Switching Sequence design for five level npc h bridge inverters with improved output voltage spectrum and minimized device Switching frequency
IEEE Transactions on Power Electronics, 2007Co-Authors: Zhongyuan Cheng, Bin WuAbstract:This paper presents a novel Switching Sequence design for the space-vector modulation of high-power multilevel converters. The Switching Sequences are optimized for the improvement of harmonic spectrum and the minimization of device Switching frequency. Compared to other commonly used Switching Sequences, the output spectrum of the proposed design shows higher inverter equivalent Switching frequency. Meanwhile, the device Switching frequency is reduced by using a flexible Switching pattern. The proposed Switching Sequence has been simulated and experimentally tested on a 5-level neutral point clamped H-bridge based inverter. The results from both simulations and experiments consistently verify the above-mentioned features.
