Academic Projects for

EEE M.Tech (2013-2014)  

 

 

We will develop your ideas and your papers also,

For any Further information call-9603150547

e-mail visionsolutions.9@gmail.com

 

 

 

 

 

 

 

 

 

 

 

ζ Transmission/Distribution/Protection

ζ HVAC/HVDC

ζ Concepts of Facts (UPFC/SSSC/Statcom/UPQC/TCSC)

ζ Modeling of Facts Devices in Simulink/Mat lab

ζ Distributed Generation

ζ Non Conventional Energy Sources

ζ Fuzzy/Neural Networks

ζ Uncontrollable/controllable Converters

ζ Various PWM Techniques(PWM/SPWM/SVPWM/DPWM/GDPWM)

ζ Multilevel Inverters

ζ Harmonics, Active/Passive Filters

ζ DC to DC converters(Buck/Buck Boost/Cuk/Sepic)

ζ Fuzzy/Neural Networks

 

ζ Basic Concepts of Motor

ζ AC/DC motors

ζ Electrical Drives

ζ Various speed controlling techniques of AC/DC motors

ζ Fuzzy/Neural Networks

ζ Basics of MATLAB programming/Simulink

ζ Designing of Simple circuits in Simulink

ζ Steady State Space Analysis of RLC Circuits

 

 

 

S.No CODE PROJECT TITLE YEAR

1 SMS13-01 A Carrier-Based PWM Strategy With the Offset Voltage Injection for Single-Phase Three-Level

Neutral-Point-Clamped Converters 2013

DESCRIPTION

Single-phase three-level neutral point clamped (NPC) converters are widely applied in high-speed railway electrical traction drive systems. Significant problem related to the single-phasethree-level NPC converters is the fluctuation of the neutral-point voltage. In this paper, a capacitor voltage balancing technique is proposed that injects an offset voltage into the sinusoidal modulating signals of the conventional carrier-based pulse width modulation(CBPWM) method. Furthermore, when the injected offset voltage is maximized, it cannot only balance the dc-link capacitors voltages, but also reduce switching losses. Theoretical analysis has shown that both methods can control the neutral point voltage effectively, but the neutral point voltage controller in the CBPWM with maximum offset voltage injection (CBPWM-MOVI) has a faster dynamic response. It was observed that the high-order harmonics frequencies of the line current are centered around the twice switching frequency in the CBPWM with the offset voltageinjection (CBPWM OVI) but are centered around the

2 SMS13-02 A Dual Inverter-Based Super-capacitor Direct

Integration Scheme for Wind Energy Conversion Systems

2013

DESCRIPTION

Interfacing converters used in connecting energystorage systems like super capacitors and battery banks to windpower systems introduce additional cost and power losses. Thispaper therefore presents a direct integration scheme for super capacitorsused in mitigating short-term power fluctuations in windpower systems. This scheme uses a dual inverter topology for bothgrid connection and interfacing a super capacitor bank. The maininverter of the dual inverter system is powered by the rectifiedoutput of a wind turbine-coupled permanent-magnet synchronousgenerator. The auxiliary inverter is directly connected to the super capacitor bank. With this approach, an interfacing converteris not required, and there are no associated costs and power lossesincurred. The operation of the proposed system is discussed indetail. Simulation and experimental results are presented to verifythe efficacy of the proposed system in suppressing short-term windpower fluctuations.

3 SMS13-03 A ZVS-PWM Three-Phase Current-Fed Push–Pull DC–DC Converter 2013

DESCRIPTION

In this paper, a ZVS-PWM three-phase currentfedpush–pull dc–dc converter is proposed. When compared tosingle-phase topologies, the three-phase dc–dc conversion increasesthe power density, uses the magnetic core of the transformermore efficiently, reduces the stress on switches, andrequires smaller filters since the frequency for its design is higher.The proposed converter employs an active clamping technique byconnecting the primary side of the transformer to a three-phasefull bridge of switches and a clamping capacitor. This circuitallows the energy from the leakage inductances to be reused, increasingthe efficiency of the converter. If appropriate parametersare chosen, soft-commutation of the switches (ZVS) can also beachieved. The soft-commutation improves the efficiency even further,allows higher switching frequencies to be used, and reducesthe electromagnetic interference significantly. Applications suchas fuel cell systems, transportation, and uninterruptable

 powersupplies are some examples that can benefit from the advantagespresented by this converter. The theoretical analysis, a design example,and the experimental results for a prototype implementingthis topology are presented. The prototype was designed to process4 kWat full load with an input voltage of 120 V, an output voltageof 400 V, and a switching frequency of 40 kHz.

4 SMS13-04 Adaptive MPPT Applied to Variable-Speed Micro-hydropower Plant 2013

DESCRIPTION

Variable-speed micro hydropower energy systemshave recently received significant attention in the renewable energyfield, due to its overall efficiency and great potential availableworldwide. This emergent technology combined with maximumpower point tracking (MPPT) techniques allows us to replace theburden classical governing mechanical systems, being a very effectiveway of ensuring high energy efficiency when operating in freewater flows. In this paper, a variable-speed micro hydropower plantbased on a semi-Kaplan turbine is employed and a novel adaptivehigh-performance MPPT technique is proposed. This allows hightracking quality due to superior dynamic response and high

5 SMS13-05

An Energy-Efficient Motor Drive With Autonomous Power Regenerative Control System Based on

Cascaded Multilevel Inverters and Segmented Energy Storage

2013

DESCRIPTION

This paper presents a cascaded-multilevel-inverter basedmotor drive system with integrated segmented energy storage.A power-distribution strategy among the energy source, thesegmented energy storage, and the electric motor is proposed underdifferent operation modes. A design guideline for energy storageis provided to meet the proposed power-distribution strategy.Moreover, the energy storage features not only implementing theharmonic compensation in all operating modes but also providingpeak power during acceleration and absorbing regenerative powerduring deceleration, which improves the energy efficiency of themotor drive system and reduces the size of the energy source. Anautonomous power regenerative control system including voltagebalancing control of segmented energy storage is developed toperform the smooth power transition between different operationmodes and provide accurate speed tracking. A 5.5-kW permanent-magnet synchronous motor (PMSM) drive system has beenbuilt in the laboratory. Simulation and experimental results areprovided to demonstrate the effectiveness of the proposed motordrive system.

6 SMS13-06 Analysis, Modeling, and Implementation of a

Multidevice Interleaved DC/DC Converter for Fuel Cell Hybrid Electric Vehicles

2013

DESCRIPTION

Multiphase converter topologies for use in highperformanceapplications have received increasing interest in recentyears. This paper proposes a novel multidevice interleaved boost converter (MDIBC) that interfaces the fuel cell with thepowertrain of hybrid electric vehicles. In this research, a Multidevice structure with interleaved control is proposed to reduce theinput current ripples, the output voltage ripples, and the size of passive components with high efficiency compared with the othertopologies. In addition, low EMI and low stress in the switches areexpected. The proposed dc/dc converter is compared to other convertertopologies such as conventional boost converter (BC), Multidevice boost converter (MDBC), and two-phase interleaved

 boostconverter (IBC) to verify its dynamic performance. Furthermore,a generalized small-signal model is derived for these dc/dc converters,which has not been previously discussed. A digital dual-loopcontrol is designed to achieve the proper regulator for the converterswith fast transient response. The dc/dc converter topologiesand their controller are designed and investigated by usingMATLAB/Simulink. Finally, the proposed converter (MDIBC) isexperimentally validated with results obtained from a 30-kW prototypethat has been built and tested in our laboratory based onTMS320F2808 DSP. The simulation and experimental results havedemonstrated that the proposed converter is more efficient thanother dc/dc converter topologies in achieving high performanceand reliability for high-power dc/dc converters.

7 SMS13-07 Control Strategy for Power Flow Management in a PV System Supplying DC Loads 2013

DESCRIPTION

The growing concern for energy saving has increasedthe usage of LED-based street lights, electronic chokes, compactfluorescent lamps, and inverter-fed drives. Hence, the load profile seen by the electrical grid is undergoing a notable change as these devices have to operate from a dc source. Photovoltaic (PV)being a major energy source, the aforementioned loads can be connected directly to the dc bus. A grid-connected PV system involves a power source (PV array), a power sink (load), and two power sources/sink (utility and battery), and hence, a power flow management system is required to balance the power flow among these sources. One such system is developed for selecting the operating mode of the bidirectional converter by sensing the battery voltage. The viability of the scheme has been ascertained by performing experimental studies on a laboratory prototype. The control strategy is digitally implemented on an Altera Cyclone II Field Programmable Gate Array (FPGA) board, and the algorithm is verified for different modes of operation by varying the load. Experimental results are presented to bring out the usefulness of the control strategy.

8 SMS13-08 Control Structure for Single-Phase Stand-Alone Wind-Based Energy Sources 2013

DESCRIPTION

This paper is analyzing the operation of a stand-alone wind turbine system with variable-speed permanent-magnet synchronous generator (PMSG) and a system for storing energy during wind speed and load variations. Energy storage devices are required for power balance and power quality in stand-alone wind energy systems. Initially, the holistic model of the entire system is achieved, including the PMSG, the boost converter, and the storage system. The power absorbed by the connected loads can be effectively delivered and supplied by the proposed wind turbine and energy storage systems, subject to an appropriate control method. The main purpose is to supply 230-V/50-Hz domestic appliances through a i l h i t Th i l ti lt lid t d b i t l

9 SMS13-09 Controller Design and Implementation of Indirect Current Control Based Utility-Interactive Inverter

System 2013

DESCRIPTION

The utility-interactive inverter with critical loadshould be able to provide critical loads with a stable and seamlessvoltage. This letter proposes an indirect current controller whichdoes not include any nonlinear factors in the control block, so thatthe classical control theory can be applied to the controller design.Also, a phase-locked loop algorithm is proposed to maintain theconstant frequency across the critical load during the unintentionalislanding since the magnitude is well regulated, but the

 frequencymay vary with the proposed controller. Further, an islanding detectionmethod is proposed for the controller, which does not cause a change in magnitude and frequency of critical load voltage.

10 SMS13-10 Coordinated Control of Cascaded Current-Source Converter Based Offshore Wind Farm 2013

DESCRIPTION

Offshore wind farms with cascaded PWM current-source converters (CSCs) at both generator- and grid-sidecan eliminate the need for bulky central offshore converter platform,which is usually used in a voltage-source converter (VSC)based counterpart. This novel system structure can simplify thesystem configuration and operation. However, the wind speedinconsistency at each turbine causes different dc-link currentrequirements for each CSC. This causes a considerable challengefor systems in which each CSC shares equal dc-link current. Inorder to overcome the problem, a coordinated control scheme forthe dc-link current regulation, which considers wind speed differenceof each turbine, is proposed. This control scheme enablesthe system to operate at minimum dc-link current, contributingto a lower operation losses. In the meantime, the independentcontrol capability of each generator is guaranteed (e.g., maximumpower tracking to make full utilization of available wind energy).Furthermore, the whole wind farm control strategy, which consistsof wind farm supervisory control (WFSC), local wind turbinecontrol and centralized grid control, is investigated and studied,where maximum power tracking and power limitation modes canbe easily achieved. Both simulation and experimental verificationof the proposed system with use of two permanent-magnet synchronous generators (PMSGs) are provided.

11 SMS13-11 Coordinated Damping Control Design for DFIG-Based Wind Generation Considering Power Output Variation 2013

DESCRIPTION

To alleviate the impacts of stochastic wind generationon stability performance, this paper proposes a novel control designmethod for coordination and synthesis of damping controllersfor conventional synchronous generators (SG) and double fedinduction generators (DFIG)-based wind generation in multi-machinepower systems. A probabilistic model of wind generationunderWeibull distribution of wind speed is first introduced. Basedon this model, an extended probabilistic small signal stability analysis(SSSA) incorporating wind power generation is proposed forhandling probability density function (PDF) of its power output.The optimization problem for tuning of damping controllers isthen formulated, considering the cumulative distribution function(CDF) of the real part and damping ratio of eigenvalues obtainedby the proposed probabilistic SSSA as stability constraints. Particleswarm optimization (PSO) is used to solve the optimizationproblem and to determine parameters of damping controllers.The effectiveness of the proposed method is demonstrated onthe modified New England power system with multi-wind farms through probabilistic SSSA and transient stability analysis, and itis compared with conventional deterministic methods. Accuracy of the proposed probabilistic SSSA is also validated by Monte Carlo simulations (MCS).

 

12 SMS13-12 DC-Bus Design and Control for a Single-Phase Grid-

Connected Renewable Converter With a Small Energy Storage Component

2013

DESCRIPTION

This paper presents a control design approach foroptimum dynamic response in single-phase grid-connected renewableconverters with minimum energy storage components. This isa crucial matter in realizing compact and robust converters withoutuse of bulky and sensitive electrolytic capacitors. Nonoptimum dynamic response results in undesired interruptions of the maximumpower point tracking and reduction of theoverall efficiencyof the system. Common practice is to select a large dc-bus size inOrder to reduce the double-frequency ripples that cause harmonicsand to slow down the dynamic response to avoid large fluctuationson the bus caused by random input power jumps. This paper showsthat both problems can be addressed to a great extent by improvingthe control system and without need to excessively increase thesize of the bus component. This paper proposes a control systemto

hi th l d id l ti l d i th dt ti i13 SMS13-13 Design Methodology for a Very High Frequency

Resonant Boost Converter 2013

DESCRIPTION

This paper introduces a designmethodology for a resonantboost converter topology that is suitable for operation at veryhigh frequencies. The topology we examine features a low partscount and fast transient response, but suffers from higher device Stresses compared to other topologies that use a larger number ofpassive components. Numerical design procedure is developed forthis topology that does not rely on time-domain simulation sweepsacross parameters. This allows the optimal converter design to befound for a particular main semiconductor switch. If an integratedpower process is used where the designer has control over layoutof the semiconductor switch, the optimal combination of converterdesign and semiconductor layout can be found.

lid h d l d d i h14 SMS13-14 Differential Power Processing for Increased Energy

Production and Reliability of Photovoltaic Systems 2013

DESCRIPTION

Conventional energy conversion architectures in photovoltaic(PV) systems are often forced to tradeoff conversion efficiencyand power production. This paper introduces an energyconversion approach that enables each PV element to operate at itsmaximum power point (MPP) while processing only a small fractionof the total power produced. This is accomplished by providingonly the mismatch in the MPP current of a set of series-connectedPV elements. Differential power processing increases overall conversionefficiency and overcomes the challenges associated withunmatchedMPPs (due to partial shading, damage, manufacturingtolerances, etc.). Several differential power processing architecturesare analyzed and compared with Monte Carlo simulations.Local control of the differential converters enables distributed protection and monitoring. Reliability analysis shows significantly increasedoverall system reliability. Simulation and experimental resultsare included to demonstrate the benefits of this approach atboth the panel and subpanel level.

 

15 SMS13-15 Digital Plug-In Repetitive Controller for Single-Phase Bridgeless PFC Converters 2013

DESCRIPTION

This paper investigates a plug-in repetitive controlscheme for bridgeless power factor correction (PFC) convertersto mitigate input current distortions under continuous conductionmode and discontinuous conduction mode operating conditions.From the PFC converter model and the fact that a type-II compensatoris used, a design methodology to maximize the bandwidth ofthe feedback controller is suggested. After that, the error transferfunction including the feedback controller is derived, and the stabilityof the repetitive control scheme is evaluated using the errortransfer function. The implementation of the digital repetitive controlleris also discussed. The simulation and experimental resultsshow that the input current THD is significantly improved by usingthe proposed control scheme for a 1-kW single-phase bridgelessPFC converter prototype.

16 SMS13-16 Digital-Controlled Single-Phase Transformer-Based Inverter for Non-Linear Load Applications 2013

DESCRIPTION

The paper presents a new digital-controlledsingle-phase transformer-based inverter for non-linear loadapplications. A capacitive full-bridge circuit is added to provideinstant current under non-linear load condition and thereby reducingthe harmonics significantly to meet the required harmonicstandard, IEEE 519-1992, even under non-linear load condition.The redundant capacity, cost, size and weight of line frequencytransformer can therefore be dramatically reduced. Moreover,a new integrated controller for inverter control is proposed toeliminate both DC current component and steady state error evenunder heavy load condition. The proposed integrated controllerconsists of a Proportional (P) controller acts as voltage controller,DC offset canceller, an RMS compensator and non-linear loadcompensator.Experimental results derived fromaDSP-based inverter systemwill be presented. The inverter rating is 1.5 kVA. It will be shownthat both redundant capacity of line frequency transformer andvoltage harmonics are significantly reduced even with non-linearload. It will also be demonstrated that the DC current componentand steady state error are eliminated even under heavy load condition.These experimental results therefore confirm the superb performanceof the proposed inverter and control techniques.

17 SMS13-17 Digital-Scalar PWM Approaches Applied to Four-Leg Voltage-Source Inverters 2013

DESCRIPTION

In this paper, we present two modulation schemesfor generating unbalanced voltages by means of four-leg voltagesourceinverters. The first modulation is an extended scheme ofa digital-scalar pulsewidth modulation previously proposed forcontrolling three-leg inverters. The second one is based on thedecomposition of the voltage reference signals into their symmetricalcomponents. The schemes are compared theoretically bysimulations and experimental results. As a consequence, we findout a total equivalence between the two modulations despite theirdifferent conceptions. The fundamentals of both techniques anda mathematical proof of their equivalence are unfolded Also the

18 SMS13-18 Dual Transformer less Single-Stage Current Source 2013

 Inverter With Energy Management Control Strategy

DESCRIPTION

Alternative energy sources have for some time attractedgreat interest in the area of static converter development.This fact is related in greater part to issues such as sustainabilityand detrimental effects on the natural environment, which all contribute to the viability of this type of energy source. In this context,power electronics performs important tasks making viable the connectionof all these kind of clean power sources to the conventionalgrid and also to the load. From this perspective, a new challengemust be faced which is the development of energy managementsystems capable of providing intelligent planning and control ofappliances in low- and high-power applications. That being so, thispaper intends to contribute presenting a novel dual transformerlesssingle-stage current source inverter fed by a proton exchange membrane fuel cell (PEMFC) and a photovoltaic (PV) array. Highvoltage gain and totally controlled output voltage can be achievedwithout using dedicated step-up dc–dc converters or transformerseither. The main feature of this inverter structure is the intelligentpower management technique which focuses on the extraction ofmaximum power from the PV array keeping the PEMFC as anenergy storage system. Theoretical analysis is presented and corroboratedby experimental results of a 400Wlaboratory prototype.

19 SMS13-19 FPGA-Based Predictive Sliding Mode Controller of a Three-Phase Inverter 2013

DESCRIPTION

This paper proposed a novel predictive variablestructure-switching-based current controller for a three-phaseload driven by a power inverter. The design specifications are robustnessto load electrical parameters, fast dynamic response, reducedswitching frequency, and simple hardware implementation.In order to meet previous specifications, a sliding mode controllerhas been developed, which is designed as finite-state automata,and implemented with a field-programmable gate array (FPGA) device. The switching strategy implemented within the state transitiondiagram provides for a minimum number of switches bythe three-phase inverter that is confirmed through simulation andexperimental results. Its regulation using the proposed controllaw provides good transient response by the brushless ac motor control. However, this does not limit the wider applicability of theproposed controller that is suitable for different types of ac loads(rectifier and inverter) and acmotors (induction, synchronous, andreluctance). A new logical FPGA torque and speed controller isdeveloped, analyzed, and experimentally verified.

20 SMS13-20 Half-Wave Cyclo-converter-Based Photovoltaic Micro-inverter Topology With Phase-Shift Power Modulation 2013

DESCRIPTION

A grid-connected micro inverter with a reduced numberof power conversion stages and fewer passive componentsis proposed. A high-frequency transformer and a series-resonanttank are used to interface the full-bridge inverter to the half-wavecycloconverter. All power switches are switched with zero-voltageswitching. Phase-shift power modulation is used to control the outputpower of the inverter. A steady-state analysis of the proposedtopology is presented to determine the average output power ofthe inverter. Analysis of soft switching of the full-bridge and thehalf-wave cycloconverter is presented with respect to voltage gain,quality factor, and phase shift of the inverter. Simulation and experimentalresults are presented to validate the operation of the proposed topology.

 

21 SMS13-21 High-Performance Control of a DC–DC Z-Source Converter Used for an Excitation Field Driver 2013

DESCRIPTION

The electromechanical interface is a synchronousmachine,because its field winding permits direct management of themagnetization during speed variations. For systems with a commondc-link for the drive and excitation converters, the efficiencyis increased if the excitation drive has boosting capability. It isshown that with the proposed control strategy the Z-source converteris suitable for this application, becoming a better alternativethan the typically used buck converter. The Z-source converter, incombination with the proposed multiloop control law, can achievethe desired voltage reference swing and high-performance tracking.An analytical comparison between the dominant losses of thebuck topology, typically used in FESS, and the Z-source convertershows that the latter has higher efficiency for this application. Theparameters of the converter prototype were experimentally identifiedand used to implement the proposed controller. The controlstrategy uses the two duty cycles as manipulated variables, one toallow tracking fast changes in the reference signal and the otherto adapt the system to the slow changes. The combined action onboth inputs contributes to the compensation of the no minimumphase response of the Z-converter. Experimental results show thepotential of the controller for tracking typical FESS application waveforms.

22 SMS13-22 Improved Transformerless Inverter With Common-

Mode Leakage Current Elimination for a Photovoltaic Grid-Connected Power System

2013

DESCRIPTION

To eliminate the common-mode leakage current in thetransformerless photovoltaic grid-connected system, an improvedsingle-phase inverter topology is presented. The improved transformerlessinverter can sustain the same low input voltage as thefull-bridge inverter and guarantee to completelymeet the conditionof eliminating common-mode leakage current. Both the unipolarsinusoidal pulse-width modulation (SPWM) as well as the doublefrequencySPWM control strategy can be applied to implementthe three-level output in the presented inverter. The high efficiencyand convenient thermal design are achieved thanks to the decouplingof two additional switches connected to the dc side. Moreover,the higher frequency and lower current ripples are obtainedby adopting the double-frequency SPWM, and thus the total harmonicdistortion of the grid-connected current are reduced greatly.Furthermore, the influence of the phase shift between the outputvoltage and current, and the influence of the junction capacitancesof the power switches are analyzed in detail. Finally, a 1-kW prototypehas been simulated and tested to verify the theoretical analysisof this paper.

23 SMS13-23 Improved Voltage-Vector Sequences on Dead-Beat

Predictive Direct Power Control of Reversible Three-Phase Grid-Connected Voltage-Source Converters

2013

DESCRIPTION

This paper presents a dead-beat predictive directpower control (DPC) strategy and its improved voltage-vector sequencesfor reversible three-phase grid-connected voltage-sourceconverters (VSCs). The instantaneous variation rates of active andreactive powers, by applying each converter voltage vector in 12different sectors, are deduced and analyzed. Based on the powervariation rates, it is found that the values of the predicted durationtimes for the two conventional active converter voltage vectors areless than zero when the grid-connected VSC operates as either arectifier or an inverter. In order to solve this issue, two new

 alternativevector sequences are proposed and compared. Experimentalresults on a 1.5 kW reversible grid-connected VSC system are presentedto validate the feasibility of the proposed voltage-vectorsequences on the dead-beat predictive DPC strategy.

24 SMS13-24 Instantaneous Current-Sharing Control Strategy for

Parallel Operation of UPS Modules Using Virtual Impedance

2013

DESCRIPTION

By regulating the inverter output current everyswitching cycle, instantaneous current-sharing control strategiesare usually employed in paralleled modular uninterruptible powersupplies (UPSs). In this paper, virtual impedance, which is usuallyutilized in the droop method, is firstly introduced to the instantaneouscurrent-sharing control strategy to achieve good loadcurrent-sharing performance. The instantaneous circulating currentmodel of the paralleled system is developed and the circulatingimpedance is derived as well to clearly identify the intrinsicnature of unequal sharing of load current. By inserting the virtualimpedance to the circulating impedance with the help of propercontrol strategy, good current-sharing capability can be obtained.The parallel inductor, e.g., coupled inductor, which is generallyadded at the output of each inverter to reduce the circulating currentamong modules, can be, therefore, eliminated, contributingto reduced weight, volume, and cost. In the meantime, the systemoutput-voltage regulation performance, e.g., amplitude andwaveform quality is not affected by the introduction of the virtualimpedance. The designation of the virtual impedance is providedand its implementation is simple but rather effective. Experimentalresults are also provided to verify the feasibility of the proposed method.

25 SMS13-25 Low-Common Mode Voltage H-Bridge Converter with Additional Switch Legs 2013

DESCRIPTION

H-bridge converter with additional switch legs (HAconverter) and its offspring circuit are proposed in this paper withthe intent to reduce the common mode noise. The proposed topologyconnects grounds of the input and output terminals, whichgives zero common mode current in the ideal case. The operationof the proposed circuit is flexible and allows for the circuit to becapable of both ac–dc and dc–ac conversions. The proposed topologyis especially advantageouswhen it is applied to the photovoltaicpower conditioning system in dc distribution system or stand-alonepower system because they include large stray capacitances andare prone to common mode EMI. In this paper, a 4-switch HA(HA4S) converter for both ac–dc rectification and dc–ac inversionis derived from the proposed HA converter as the implementationexample. The experimental results based on the proposed andthe conventional prototype circuits prove that the HA4S converteroutperforms the conventional counterparts.

26 SMS13-26 Modelling, Analysis, and Design of an Interleaved

Four-Phase Current-Fed Converter With New Voltage Multiplier Topology

2013

 

DESCRIPTION

The objective of this paper is focused on developingan interleaved four-phase current-fed converter with new voltagemultiplier topology for low-voltage distributed energy generation systems. The proposed four-phase current-fed converter is withthe interleaved configuration and preserving the inherent advantagesof smaller input current ripple and smaller inductance size.Through the proposed topology, the high voltage gain can beachieved using the relatively lower transformer turns ratio. Also,the voltage stresses of both active switches and rectifier diodesare greatly reduced so that the low on-resistance active switchescan be adopted, and the reverse-recovery effect of rectifier diodescan be decreased naturally. The dc and ac small signal models of the proposed converter topology are derived for better closedloop control, and some design guidelines are then given for circuitimplementation. Both simulation and experimental results indeedverify the effectiveness of the proposed converter.

27 SMS13-27 New Overall Power Control Strategy for Variable-

Speed Fixed-Pitch Wind Turbines Within the Whole Wind Velocity Range

2013

DESCRIPTION

Variable-speed fixed-pitch (VSFP) wind turbineshave good prospects in small-to-medium-scale wind power marketsdue to their simple structure, low cost, and high reliability.One difficulty with VSFP concept wind turbines is to prevent overspeeding and overloading problems at excessive wind velocities,which has rarely been reported in literatures until now. This paperfirst proposes a sensorless overall power control strategy for acommonly used permanent-magnet-synchronous-generator-basedVSFP concept wind power system, with which maximum powerpoint tracking operation, constant speed stalling operation, andconstant power soft-stalling operation are all realized. The proposedcontrol scheme has a special advantage of simple structure,i.e., only two regulators are used to realize the three operationalmodes and also the natural transition between them. An aerodynamicpower observer is adopted in the proposed scheme tofasten the MPPT speed. In addition, to enhance system robustnessto parameter variations and optimize dynamic and static speedcontrolperformance, an adaptive PI-like fuzzy logic controlleris proposed and used as speed regulator in the overall powercontrol scheme. The proposed strategy is verified by simulationand experimental results performed by a 1.2-kW VSFP concept wind turbine prototype.

28 SMS13-28 One-Cycle-Controlled Single-Stage Single-Phase Voltage-Sensorless Grid-Connected PV System 2013

DESCRIPTION

Reforms in the electricity sector along with variousrenewable-energy-promotion policies have increased the importanceof small grid-connected photovoltaic (PV) systems utilizingsingle-stage single-phase inverters. Ruggedness, reliability, andcost effectiveness are the desirable characteristics of such invertersused in distributed low-power applications. Schemes based onone-cycle control (OCC) which do not require the service of aphase-locked loop for interfacing the inverter to the grid areincreasingly being employed for such applications. However, theOCC-based schemes reported earlier require sensing of the gridvoltage which somewhat offsets one of the inherent strengths ofOCC-based systems. In an effort to overcome the aforementioned limitation, an OCC-based grid-connected single-stage PV systemis proposed in this paper which does not require to sense thegrid voltage. Further, it requires less number of sensors (two) ascompared to that

 required (four) in the earlier reported scheme for the implementation of the core controller comprising of OCCand maximum-power-point-tracking blocks. The viability of the proposed scheme is confirmed by performing simulation and experimental validation.

29 SMS13-29 Reactive Power Control of Permanent-Magnet Synchronous Wind Generator With Matrix Converter 2013

DESCRIPTION

In this paper, the reactive power control of a variablespeedpermanent-magnet synchronous wind generator with a matrixconverter at the grid side is improved. A generalized modulationtechnique based on singular value decomposition of themodulationmatrix is used to model different modulation techniques andinvestigate their corresponding input reactive power capability.Based on this modulation technique, a new control method is proposedfor thematrix converter which uses active and reactive partsof the generator current to increase the control capability of thegrid-side reactive current compared to conventional modulationmethods. A new control structure is also proposed which can controlthe matrix converter and generator reactive current to improvethe grid-side maximum achievable reactive power for allwind speeds and power conditions. Simulation results prove theperformance of the proposed system for different generator outputpowers.

30 SMS13-30 Secondary-Side Phase-Shift-Controlled ZVS DC/DC Converter With Wide Voltage Gain for High Input

Voltage Applications 2013

DESCRIPTION

In this paper, a soft-switching dc/dc converter withsecondary-side phase-shift control strategy is proposed to improvethe conversion efficiency and minimize the primary switch voltagestress in the high input voltage applications. Zero-voltageswitchingperformance is achieved for both the primary- andsecondary-side power devices in a wide load range to reducethe switching losses due to the secondary-side phase-shift controlscheme. Furthermore, compared with the conventional phase-shiftcontrol mechanism, the circulating current at the freewheelingstage is effectively suppressed as well to minimize the conductionlosses. Moreover, the voltage stress of the primary switches is onlyhalf of the input voltage by employing the improved three-levelstructure, which makes the low-voltage rated power devices availableto improve the circuit performance. In addition, the convertercan work in the buck, balance, and boost modes to achieve a relativelywide input voltage range, which is an expected advantage forthe communication power system to minimize the electrolytic capacitorswith an acceptable hold-up time. The operation principleis analyzed and experimental results of a 1-kW 100-kHz prototypeare provided to verify the effectiveness and the advantages of theproposed converter

31 SMS13-31 Sensorless Control of CSC-Fed IPM Machine for Zero-

and Low-Speed Operations Using Pulsating HFI Method

2013

DESCRIPTION

In this paper, a sensorless method for low- andzero-speed operations is proposed for a high-power medium-voltage pulse-width-modulated current-source-converter-fedinterior-permanent-magnet motor drive system. The proposedmethod is based on the injection of a high frequency (HF) pulsatingsinusoidal signal in the estimated synchronous referenceframe of the drive’s field-oriented control (FOC) scheme. The conventionalFOC control scheme, low switching frequency, dc-linkinductor, and the inverter output three-phase filter capacitor of themedium-voltage high-power current-source drive present

 somechallenges in the generation and design of the HF-injection signal.To overcome these challenges, the FOC scheme is modifiedby introducing a modulation index control with suitable dc-linkcurrent compensation to enhance the dynamic response of theinjected signal and prevent any clamp in the injected signal.In addition, a multisampling-space-vector-modulation method isproposed to prevent the distortion in the HF signal due to a lowswitching frequency to injected signal ratio. A detailed study andanalysis regarding the influence of low switching frequency, outputfilter capacitor, and magnetic saturation in the injection methodis carried out to determine the visible HF range of the injectedsignal. It is found that, by using the proposed FOC scheme andmultisampling modulation scheme and by the proper design ofthe HF signal, an accurate rotor flux angle can be estimated forsensorless zero-/low-speed operations. Experimental results areprovided to verify the proposed control method.

32 SMS13-32 Sine-Wave Amplitude-Modulation Concept for Linear Behavior of Phase-Modulated Resonant Converters 2013

DESCRIPTION

This paper focuses on a dc–ac resonant power converterusing a special sine-wave amplitude-modulation conceptwith the objective of achieving a linear input–output behavior,low harmonic content at the output, and reduced stages number.This technique can be applied to a wide range of resonantconverters’ applications. Sine-wave generation techniques andphase-modulation method limitations are analyzed. Alternativesolutions, such as a new predistorted phase modulator, are developed.A prototype was designed and implemented. Presented experimentalresults demonstrate the effectiveness of the presentedprinciple.

33 SMS13-33 Variable Switching Frequency PWM for Three-Phase Converters Based on Current Ripple Prediction 2013

DESCRIPTION

Compared with the widely used constant switchingfrequency pulse-width-modulation (PWM) method, variableswitching frequency PWM can benefit more because of the extrafreedom. Based on the analytical expression of current ripple ofthree-phase converters, variable switching frequency control methodsare proposed to satisfy different ripple requirements. SwitchingcycleTs is updated inDSP in every interruption period based on theripple requirement. Two methods are discussed in this paper. Thefirst method is designed to arrange the current ripple peak valuewithin a certain value and can reduce the equivalent switching frequencyand electromagnetic interference (EMI) noise; the secondmethod is designed to keep ripple current RMS value constantand reduce the EMI noise. Simulation and experimental resultsshow that variable switching frequency control could improve theperformance of EMI and efficiency without impairing the power quality.

34 SMS13-34 Very Fast Measurement of Low Speed of Rotating Machines Using Rotating Magnetic Field 2013

DESCRIPTION

The measurement at low speed becomes very difficultdue to the slow response of transducers. At low speed (below10 r/min), normally, transducers take several seconds to give therequired output signal. In the proposed technique, a fast rotatingmagnetic field (RMF) is used to measure the speed as well asdeviation in speed for low-speed machines. A sine wave oscillator(single-phase ac source) is used to generate a balanced three-phaseac voltage, which is applied to the stator windings of a

 

 

synchrowhose rotor is coupled with the rotating member or rotor ofa motor. The RMF in the air gap generates emf in the rotorof the synchro whose frequency depends upon the slip speed.Since the RMF revolves at a speed several times the speed of therotating member or the rotor of the motor, hence the measurementbecomes very fast. The proposed scheme is tested successfully evenat 1 r/min, and the overall performance is recorded at dynamicconditions. The results of the measurements are compared with aconventional method (tachogenerator), which shows the accuracyof the proposed method. The output is also obtained in terms ofdc voltage and dc current, which can be used for feed-back andcontrol applications.