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Human readable symbols are extracted from a trained neural network using Rule Extraction Techniques. In this paper internal representation of feed forward neural network is augmented by a distance term to produce fewer rules. This paper presents an efficient method to extract fewer rules from multilayer feed forward neural network. The proposed method calculates distance between activation values...
The modular multilevel converter (MMC) is a highly efficient multilevel converter topology suitable for high and medium voltage applications. However, one of the negative traits of MMC is the existence of circulating current. The detrimental effects of circulating currents include distortion in arm voltages, converter power loss and high switching stresses on semiconductor devices. This paper aims...
This paper deals with the implementation of Hybrid Series Active Power Filter (HSAPF) for compensation of harmonic voltage and current using Space Vector Pulse Width Modulation (SVPWM) technique. The Hybrid control approach based Synchronous Reference Frame(SRF) method is used to generate the appropriate reference voltages for HSAPF to compensate reactive power. This HSAPF uses PI control to the outer...
This paper proposes asymmetrical fuzzy logic control (AFLC) for PV module connected micro grid. PV module connected micro grid is considered as two stages control, (i) maximum power point tracking control, and (ii) three phase PWM voltage source control. Voltage source converter (VSC) is used for interfacing solar energy with the micro grid and the dc link voltage is regulated using conventional and...
This paper presents a discrete derivative control technique for dc-link voltage in shunt compensator. It is desired to maintain the dc-link voltage at reference level value for current compensation using Distribution Static Compensator (DSTATCOM) to improve the power quality of distribution systems. The proposed control strategy improves the dynamic performance of DC control loop by taking the values...
The multicell converter is used to enhance the converter rating and improve the power quality on input AC side. The conventional multicell AC-DC converter with fixed hierarchy of H-bridge cells leads to unbalanced voltages across the DC side of the cells. This paper presents a hierarchal hysteresis current controlled cascaded H-bridge multicell AC-DC converter. The problem of unbalanced voltages has...
Phase shifted carrier modulation is an industry standard in its application to multi-level H-bridge Converters. The major advantage of this scheme over level shifted and space vector modulation schemes is its inherent ability to evenly distribute losses between semiconductor devices. However, it has been demonstrated in literature that level shifted and space vector schemes have superior harmonic...
This paper proposes a current harmonics control method for the input current of an electrolytic capacitor-less inverter for an interior permanent magnet synchronous motor (IPMSM). In general, an IPMSM has large spatial harmonics caused by the rotor structure. The back electromotive force (EMF) of an IPMSM contains harmonics and generates three-phase current harmonics. The three-phase current harmonics...
Packed U-Cell (PUC) converter has been introduced as a 7-level converter in early 2008. Since then, different analysis and projects have been performed on, including various applications such as inverter and rectifier, linear and nonlinear voltage controllers. In this paper, authors try to do a detail review on this topology covering all aspects like topology design in single and three-phase, operation...
To meet the requirement of high reliability, practicability and stability in low cost, a multi-objective control algorithm is proposed based on split-capacitor-type three-phase four-wire distribution static generator. The control algorithm is implemented on improved ip-iq method and certain equivalent triangle conversion; then the six target components including negative, zero and base positive sequence...
This paper presents a 7-level cascaded H-bridge (CHB) multilevel inverter using a single DC source. The second DC bus is a capacitor that its voltage is controlled by switching sequences. The capacitor voltage is regulated at half of the DC source amplitude to have seven voltage levels at the output. Seven voltage levels include each DC bus voltage, their sum and subtraction. Switching pattern is...
The main objective of this work is to investigate an indirect current control scheme based on slide mode approach to regulate the currents of a three-phase Active Power Filter (APF) in such a way to improve the quality of the power supplied by a diesel generator set. The indirect current control scheme provides the signal reference to active power filter controller without the need of measurement...
The need of controlled rectifiers to provide input power factor correction with reduced harmonic content drawn from ac mains and regulated dc output voltage has motivated the proposal of various topologies based on the classical converters such as boost and buck-boost topologies. Distinct control techniques have been also introduced with the commercial availability of integrated circuits (ICs) to...
Modular multilevel converter (MMC) has been a research hotspot in the past decade in the high-voltage high-power applications. The basic working principle is analyzed in depth in this paper firstly. A precise control law is deduced to control the output voltage and the circulating current directly and precisely. Different from the conventional control law, arm inductor voltages are considered in the...
Switched inverters generate fast rates of change of common-mode voltage and are an unwanted side-effect in variable speed drive systems operated with PWM inverters. Whilst techniques have been reported that theoretically eliminate the common-more voltage, when the dead-time effects and the practical transient performance of semiconductors are considered, a common-mode voltage is still generated, even...
Recently, the operation of a new class of three-phase differential-mode inverter have been proposed and their efficacy demonstrated using a discontinuous-modulation-scheme (DMS) based differential-mode Ćuk inverter (DMCI). DMS-based DMCI has a completely-modular topological configuration. To extend this modularity of the power stage to control implementation, one has to deal with the nonlinearity...
This paper focuses on the determination of suitable carrier based pulse width modulation (PWM) switching and control methods for grid connected modular multilevel converters (MMCs). Characterization of various level-shifted and phase-shifted carrier based PWM methods are provided in terms of output voltage waveforms both for N+1 and 2N+1 level output phase voltages. Carrier based PWM method based...
A multilevel boost PFC (Power Factor Correction) rectifier is presented in this paper controlled by cascaded controller and multicarrier pulse width modulation technique. The presented topology has less active semiconductor switches compared to similar ones reducing switching losses as well as the number of required gate drives that would shrink manufactured box significantly. A simple controller...
Possibility of hybridization of switching strategies for modulated inverters of six-phase multi-inverter drive has been shown in this paper. Hybrid switching schemes can be used for control of power system with unequal voltages of dc-links. In this case the proposed combined PWM techniques of inverters insure equal magnitude of the fundamental harmonics of the phase voltages for different ratios between...
This paper proposes a variable sampling frequency model predictive control (VSF-MPC) to achieve fixed-switching frequency operation for a neutral-point clamped (NPC) inverter. The proposed control technique simultaneously considers load current control, balancing of DC-link capacitor voltages, mitigation of common-mode voltage, and elimination of even-order and inter-harmonics in the load current...
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