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  • 1. Performance Analysis of Wind - Fuel Cell Hybrid System linked with BESS-VF Controller Authored By Narayan P. Gupta, Sushma Gupta, Anil Kumar Presented By Narayan P. Gupta Department of Electrical Engineering Oriental Institute of Science & Technology, Bhopal, India
  • 2. Contents  Introduction Wind Turbine Systems  Vector Control Scheme of GSC and RSC  Solid Oxide Fuel Cell Energy Conversion System  Modeling of D-STATCOM  Simulation Results  Conclusion  Appendix  References 2
  • 3. Introduction  Wind energy is most promising renewable energy source & its share is increasing w.r.t. to installed capacity, worldwide. India has fifth largest installed capacity in the world. Due to the intermittent characteristics of wind resources, it has been a challenge to generate a highly reliable power with wind turbines. To overcome this limitation, a solid oxide fuel cell (SOFC) is used in conjunction with wind generating plant. A multi-source hybrid power system increases energy availability significantly, it becomes advantageous for practical applications that need highly reliable power regardless of location The DFIG based variable speed wind turbine (type C) is the most popular in the growing wind market.  This system uses two back-to-back PWM voltage source converters in the rotor circuit designed as grid side converter (GSC) and rotor side converter (RSC).  The vector control strategy is used for both converters 3
  • 4. Contd… These high frequency switching converters of DFIG will inject additional harmonics in the system, which are increasing with wind speed variations. Load unbalancing, Poor power factor, Harmonics, Voltage drop at PCC, Reactive Power are some of important power quality issues related with nonlinear load.  D-STATCOM is used to mitigate the voltage dip, compensate the reactive power, flicker, harmonic mitigations, load balancing and neutral current compensation. 4
  • 5. Power Quality Electric Power Quality basically refers to maintaining a near sinusoidal power distribution bus voltage at rated magnitude and frequency. Variation in voltage, current or frequency is generally termed as PQ problems  Good power quality means Constant voltage level Low harmonic distortion Less transient events Good power factor POWER QUALITY FLICKER SYSTEM TRANSIENTS ELECTROMAGNATCINTE RFERANCE SYSTEM HARMONICS VOLTAGE SAG & SWELL NOISE LOW POWER FACTOR
  • 6. Sources Of Harmonics Contd… Modern (Power-Electronic) Types Traditional (Classical) Types Transformers Rotating Machines Arc Furnaces Rectifiers Contributors     Reactive power Harmonic pollution Load imbalance Fast voltage variations Controlled Devices Inverters SMPS Cycloconverter Fluorescent Lamps HVDC Transmission Consequences  Unexpected power supply failures  Equipment overheating and failure  Electro magnetic interferences and noise in power system  Increase of system losses  oversize installations to cope with additional electrical stress  Malfunction of protective relaying and voltage sensitive devices  Mains voltage flickering 6
  • 7. Simulink Test System A_SOFC A a B_SOFC B b Discrete, T s = 5e-006 s. Wind C C_SOFC SOFC c Wind Speed m/s Breaker Wind Turbine Tm m A_grid A a aA A a B_grid B b bB B b C_grid C c cC C [output] c + 15 KW DFIG PCC A B C Transformer 33KV/440V Grid A B C A B C - Pulse_RSC Pulse_GSC Controller g g Pulses Non Linear Load C H O K E + + DST AT COM Controller A A B - + B Grid Side Converter C B b C c C C A a Cdc B g A Rotor Side Converter Transformer BESS DSTATCOM Fig. Simulink configuration of test system 7
  • 8. Vector control Scheme of Grid Side Converter  Grid Side Converter is used to maintain the dc-link voltage constant  The voltage oriented vector control technique is used to control the GSC  The PWM converter is current regulated with the direct axis current is used to regulate the DC link voltage where as the quadrature axis current component is used to regulate the reactive power  The reactive power demand is set to zero to ensure the unit power factor operation The voltage balance across the line is given by Fig. – Schematic diagram of GSC Using the abc-to-dq transformation, the corresponding equation in the dq-reference frame rotating at ωe is 8
  • 9. Contd… The control scheme utilizes current control loops for id and iq The id demand being derived from the dc-link voltage error, through a standard PI controller The iq demand determines the reactive power flow between the grid and grid side converter The iq demand is set to zero to ensure unit power factor operation. Vd D- axis grid voltage Vq Q- axis grid voltage Vd1 D- axis grid side converter voltage Vq1 Q- axis grid side converter voltage id D- axis grid side converter current iq Q- axis grid side converter current Fig. – Vector Control Scheme of GSC 9
  • 10. Vector control Scheme of Rotor Side Converter  The main purpose of the machine side converter is to maintain the rotor speed constant irrespective of the wind speed  Vector control strategy has been implemented to control the active power and reactive power flow of the machine using the rotor current components  The active power flow is controlled through idr  The reactive power flow is controlled through iqr  To ensure unit power factor operation like grid side converter the reactive power demand is also set to zero (Qref = 0)  The currents iq and id can be controlled using Vq and Vd respectively  The control scheme utilizes cascade control  The inner current control loops are used for controlling the d-axis and q-axis rotor currents  The outer power control loops are used to control the active and reactive power on the stator 10
  • 11. Contd… The d-q axis rotor voltage equation is given by, Vdr* and Vqr* equation is given by,  Where V'dr and V'qr are found from the current errors processing through standard PI controllers  The q-axis reference current i*qr is found from the reactive power errors  The reference current i*dr can be found either from the reference torque or form the speed errors (for the purpose of speed control) through standard PI controllers Where Te*=(Pmech-Ploss)/ωr Ploss = Mechanical Losses + Electrical Losses 11
  • 12. Contd… Fig. – Vector Control Scheme of RSC 12
  • 13. Fuel Cell Energy Conversion System      Fuel cell converts chemical energy of a reaction into electricity with byproduct of water and heat . Fuel cell consists of an electrolyte layer in contact with two electrodes on either side. Hydrogen fuel is fed to anode and oxygen from air is fed to cathode. At anode Hydrogen is decomposed into positive and negative ions Only positive ions flow from anode to cathode . Recombination of positive and negative ions with oxidant takes place at cathode to form depleted oxidant (or pure water). Anode Reaction: Cathode Reaction: Overall Reaction: The dc Voltage across FC stack is given by nernest’s equation Where Vfc – Operating dc voltage (V),E0 – Standard reversible cell potential (V), pi – Partial pressure of species i (Pa), r – Internal resistance of stack (S), I – Stack current (A), N0 – Number of cells in stack, R – Universal gas constant (J/ mol K), T – Stack temperature (K), F – Faraday’s constant (C/mol) 13
  • 14. Contd…  Proton exchange membrane fuel Cell (PEMFC)  Alkaline Fuel cell (AFC)  Phosphoric acid fuel cell (PAFC)  Molten Carbonate fuel cell (MCDC)  Solid oxide fuel cell (SOFC)  Direct Methanol fuel cell (DMFC) High-temperature operation of SOFC-1800oF removes the need for a precious-metal catalyst, thereby reducing the cost. It also allows SOFCs to reform fuels internally, which enables the use of a variety of fuels (the input to the anode can be hydrogen, carbon monoxide or methane)and reduces the cost associated with adding a reformer to the system. The electrolyte used is a ceramic oxide which increases the cost of SOFCs. At the cathode, electrochemical reduction takes place to obtain oxide ions. These ions pass through the electrolyte layer to the anode where hydrogen is oxidized to obtain water. In case of carbon monoxide, it is oxidized to carbon dioxide. 14
  • 15. qH2 Pref current equation Vfc I Flow Rate equation Partial Pressure Equations qO2 pH2O pO2 pH2 r Voltage Equations N Fig. Block diagram for dynamic model of SOFC Where qH2 – Fuel flow (mol/s), qO2 – Oxygen flow (mol/s), KH2 – Valve molar constant for hydrogen (kmol/s atm), KO2 – Valve molar constant for oxygen (kmol/s atm), KH2O – Valve molar constant for water (kmol/s atm), τH2 – Response time for hydrogen (s), τO2 – Response time for oxygen (s), τH2O – Response time for water (s), τe – Electrical response time (s), τf– Fuel response time (s), Uopt – Optimum fuel utilization, rHO – Ratio of hydrogen to oxygen, Kr – Constant (kmol/s A), Pref – Reference power (kW) 15
  • 16. Power conditioning for fuel cell connected to Grid DC/DC Converter DC/AC Inverter Coupling inductor & Transmission line AC BUS DC BUS DC DC Fuel Cell Power Plant LC Filter DC Utility Grid AC Control Signal Vabc Control Signal Iabc Pulses VDCref PQ DC-DC Controller dq/abc PI - + Idref PI - Id Iqref + Qref - Pref Q + P -+ VDC PI PI Idref Iqref Iq abc/dq angle PLL Iabc Fig. Power conditioning for fuel cell connected to Grid 16
  • 17. Performance of SOFC Fuel Cell Voltage 450 The number of400 cells connected in series is taken as 450. Initially for a 50 kW of load the calculated SOFC voltage is 403 volt. The output voltage of the DC/DC converter is maintained almost constant at 700V throughout the loading 350 conditions, by using a PI controller along with the DC/DC converter. 300 Fuel Cell Voltage 450 250 400 200 350 output voltage of DC-DC converter 150 1000 300 900 100 800 250 50 700 600 Voltage (V) 2000 500 150 400 0 0.1 0.2 0.3 0.4 0.5 Time 0.6 0.7 0.8 0.9 1 Fig. Output Voltage waveform of SOFC and DC-DC Converter waveform 17 300
  • 18. Control Scheme of D-STATCOM Va Vrated Unit Voltage Template Generator Uc Ua Ub Vt Vtref _ In phase component Refrence current * * * * Iscd Isad Quadrature Voltage Templete Generator Wa Wb Wc + AC Voltage PI controller Quadrature Component Refrence current * Ismq - * Isaq * Isbq + Vabc Ig * Iamd + Frequency PI controller + * Iscq Isa Isb Prated Compensation of amplitude of active power component of current * Ismd Isbd  D-STATCOM is used to mitigate the voltage dip & compensate the reactive power.  It is also capable of flicker & harmonic mitigation’s, load balancing and neutral current compensation.  STATCOM consists of DC voltage _ source behind self commutated inverters using IGBT & coupling transformer. It is connected in shunt with distribution feeder. It generates a current injection, which is added to non sinusoidal load current. Thus phase current taken from grid will be nearly sinusoidal  With voltage/frequency controller output voltage and frequency can be kept constant Vc Vb + 0 * * * Isa Isb Isc Frequency measurement - Fref * Isn Hysteresis Current controller Isc Battery S1 S3 S5 S7 Cbattery R1 Ila Ilb Ilc Iln Lf,Rf Lf,Rf Vdc Cdc Lf,Rf Lf,Rf S4 S6 S8 + - Ro S2 Voc + 18
  • 19. Contd… Prated = 15KW Vrated = 415 volt The amplitude of active component of current is i*smd = igen(n) - ismd(n) In phase component of reference source current are estimated as: i*sad = i*smd Ua, i*sbd = i*smd Ub , i*scd = i*smd Uc  Where Ua , Ub and Uc are in-phase unit current vectors , given by Ua = Va / Vt , Ub = Vb / Vt , Uc = Vc / Vt Where Vt is the amplitude of supply voltage Vt = { 2/3(Va2 + Vb2 + Vc2)}1/2 instantaneous quadrature component of reference source current is estimated as i*saq = i*smqwa, i*sbq = i*smqwb , i*scq = i*smqwc The unity amplitude template having instantaneous value in quadrature with instantaneous voltage Va, Vb, Vc are derived as Wa = -Ua /√3 + Uc /√3 Wb= √3Ua/2 + ( Ub- Uc )/2√3 Wc= -√3 Ua/2+ (Ub-Uc)/2√3 19
  • 20. Contd… The total reference source current is the sum of in-phase & quadrature component of reference source current. i*sa = i*saq + i*sad i*sb = i*sbq + i*sbd i*sc = i*scq + i*scd The reference source current (i*sa,i*sb,i*sc) are compared with measured source current .The error of current are computed as: isa_error = isa - i*sa isb_error = isb - i*sb isc_error = isc - i*sc These error signals are the drive of hysteresis current controller to generate six firing pulses for VSC Design of BESS Controller  BESS consist of a CC-VSC with the battery at DC link. The terminal voltage of battery is given by Vbattery = (2√2/√3) VL; where VL is line rms The equivalent capacitance can be determined from Cbattery = (kwh * 3600 * 103) / 0.5 (V2ocmax – V2ocmin) The parallel circuit of R1 & Cbattery is used to describe the energy & voltage during charging & discharging 20
  • 21. -1 1.3 1.4 1.5 1.6 1.7 1.8 Simulation for Unbalanced Reactive Load supply current Iabc 20 0 Three single phase reactive load are applied between each phase and neutral at t=1.0 sec. At t=1.4sec one phase is -20 removed and another at t=1.5 sec making load unbalanced load current 50 1.3 1.4 1.5 1.6 1.7 1.8 capacitor current Ilabc 20 Icap 10 0 0 -10 -50 1.3 -20 1.3 1.4 1.4 1.5 1.5 40 1.6 1.7 1.8 1.6 controller current Time 1.7 1.8 load neutral current 1.6 1.7 1.8 Icabc 20 0 -20 -40 1.3 1.4 1.5 load neutral current 20 20 source neutral current Iln Isn Iln 20 0 10 0 0 -20 -20 1.3 -10 1.3 -20 Icn Icn 50 50 1.3 1.4 1.4 1.5 1.5 1.6 1.6 1.7 1.7 1.8 1.8 compensator neutral current compensator neutral 1.4 1.5 1.6 Time 1.7 1.8 0 0 -50 -50 1.3 1.3 1.4 1.4 1.5 1.5 1.6 1.6 1.7 1.7 1.8 1.8 21
  • 22. Simulation for Unbalanced Non Linear Load  A diode rectifier with resistive load and L-C filter at its DC side is considered. At t=1.0sec balanced non linear load is inserted at t=1.4 sec one phase is removed and another at t=1.5 sec making load unbalanced.  It seems that controller current becomes nonlinear for eliminating the harmonic current. supply voltage Vabc(pu) 1 0 -1 1.3 1.4 1.5 1.6 1.7 1.8 1.7 1.8 1.7 1.8 supply current Iabc(A) 20 0 -20 1.3 1.4 1.5 1.6 capacitor current 20 Icap(A) 10 0 -10 -20 1.3 1.4 1.5 1.6 Time 22
  • 23. Is 0 -20 0 -50 1.3 1000 Contd… 0.4 1.4 0.6 0.8 00 dc link1.6 voltage 1.5 600 0 1000 4001.3 1.3 1000 1.4 1.4 Vdc_V 1.6 Vdc_V 1.6 frequency Vdc_V frequency 1.5 1.5 1.5 1.5 1.6 1.6 1.7 1.7 1.8 1.8 500 1000 60 20 20 40 500 40 500 0 20 1.3 0 20 1.3 0 0 0 1.3 01.3 5 1.3 5 Icabc Icabc controller current controller current 0 1.4 1.5 1.4 1.4 1.5 1.5 1.4 1.4 1.5 1.5 50 1.4 1.4 load neutral current 1.6 1.5 1.5 1.6 1.7 1.7 1.8 1.7 1.8 1.7 1.7 1.8 1.8 1.7 2 0 1.6 1.8 1.6 Te 1.6 Te 1.6 1.6 Te Time Time 1.7 1.7 1.7 1.7 1.8 1.8 1.8 1.8 0 -5-5 -5 1.3 1.3 1.3 1.4 1.4 1.4 1.5 1.5 1.5 1.6 1.6 1.6 1.7 1.7 1.8 1.8 1.7 1.8 P(KW) P(KW) P(KW) 20 2020 0 0 0 0 P(KW) P(KW) P(KW) Iln 10 10 10 10 1.3 1.3 1.3 5050 10 1.4 1.4 1.4 1.4 1.5 1.5 1.5 1.5 1.6 1.6 1.7 1.7 1.6 compensator neutral current 1.7 1.6 compensator neutral current 1.7 Time Time 1.8 1.8 1.8 1.8 0 1.3 5 1.5 1.5 1.6 1.6 1.7 1.7 1.8 1.8 1.5 1.5 1.6 1.6 1.71.7 1.81.8 1.4 1.5 1.6 Q(KVAr) Q(KVAr) 1.7 1.8 Q(KVAr) 5 0 0 -5 1.3 -5 1.4 1.4 1.4 1.4 5 0 00 -50 -50 1.3 1.3 0 0 1.3 1.3 Q(KVAr) Q(KVAr) Q(KVAr) -10 -50 -50 -10 1.3 Isn Isn 1.6 0 1.8 1.8 load neutral current Source neutral current Source neutral current 50 Isn Isn Iln Te -20 -20 Te Te 5 1.3 1.3 1.4 DC link voltage 60 1.4 1.4 1.2 500 800 Vdc V f f Vdc V Vdc V Vdc Vdc Load current Load current -50 -50 1.3 1.3 1 1000 50 50 Ilabc Ilabc 0.2 1.3 1.4 1.5 1.4 1.5 1.6 Time1.6 1.7 1.8 1.7 1.8 23
  • 24. Simulation for variable Wind Speed The wind speed is varied continuously throughout the simulation time (t = 5sec) During wind speed variation, The DFIG output voltage remains constant i.e. at 1pu by maintaining the DC link voltage (Vdc) constant throughout. Though wind turbine torque (Tm) is fluctuating, the electromagnetic torque of DFIG (Tem) is constant Wind Speed (m/s) 16 Wind Speed (m/s) Ws (m/s) Ws (m/s) Ws (m/s) Ws (m/s) 16 15 Wind Speed (m/s) 15 16 14 Wind Speed (m/s) 15 16 14 14 13 15 13 0 0 13 14 0 13 20 2 2 Vabc (pu) Vabc (pu) (pu) Vabc (pu) Vabc 0.5 0.5 1 1 0.5 1.5 1.5 1 0.5 1 2 2 1.5 2.5 2.5 2 1.5 2 3 3 2.5 3.5 3.5 4 4 4.5 4.5 5 5 3 3.5 4 4.5 5 3 3.5 4 4.5 5 Generator Voltage (volt) Generator Voltage (volt) Generator Voltage (volt) 2.5 Generator Voltage (volt) 2 0 00 0 -2 -2-2 0 -2 00 0 0.5 0.5 0.5 0.5 1 11 1 1.5 1.5 1.5 1.5 2 22 2 3 3.5 4 4.5 5 33 3.5 3.5 3.5 44 4 4.5 4.5 4.5 55 5 Mechanical Torque_pu Mechanical Torque_pu Mechanical Torque_pu -0.6 Tm (pu) Tm (pu) Tm (pu)Tm (pu) 2.5 2.5 2.5 Mechanical Torque_pu -0.6 -0.6 -0.8 -0.6 -0.8 -0.8 -1 -0.8 -1 0 0 (pu) Tem (pu) u) Tem (pu) -1 1 0 1 -1 0 0 0 0.5 1 0.5 0.5 0.5 1 1 1.5 1.5 1 2 1.5 1.5 2 2.5 Electromagnetic Torque_pu Electromagnetic Torque_pu 2 2.5 2 1 -1 3 2.5 Electromagnetic Torque_pu 3.5 4 4.5 5 3 2.5 3.5 4 4.5 5 3 3.5 4 4.5 3 3.5 4 4.5 3 3 3.5 3.5 4 4 4.5 4.5 5 5 Electromagnetic Torque_pu -1 1 0 -2 -2 00 0 0.5 0.5 11 1.5 1.5 2 2 2.5 2.5 5 5 24
  • 25. Vdc (volt) Vdc (volt) (volt) Vdc Vdc (volt) Contd… Vdc (V)_ GSC & RSC Vdc (V)_ GSC & RSC Vdc (V)_ GSC & RSC 840 840 Vdc (V)_ GSC & RSC 840 840 820 820 820 820 800 800 0 0.5 0.5 800 0 800 00 1 1 0.5 0.5 1.5 1.5 11 2 2 1.5 1.5 2.5 2.5 Wr (pu)_DFIG Wr (pu)_DFIG Wr (pu)_DFIG 22 3 2.5 2.5 3 3.5 3.5 4 4 4.5 4.5 5 5 3 3 3.5 3.5 4 4 4.5 4.5 5 5 3 3.5 4 4.5 5 Wr (pu) Wr (pu) Wr (pu) Wr (pu) Wr (pu)_DFIG 1.4 1.4 1.4 1.4 1.2 1.2 1.2 1.2 1 0 1 1 0 0 0.5 1 0.5 0.5 0.5 1.5 1 1 1 2 1.5 1.5 1.5 2.5 2 22 2.5 2.5 2.5 P (KW)_DFIG P (KW)_DFIG P (KW)_DFIG P (kw) PP(kw) (kw) (kw) 20 4 44 4.5 4.5 4.5 5 55 0 0 0 -20 0 0.5 -20 20 0 1 0.5 0 1.5 1 0.5 0.5 2 1.5 1 1 2.5 2 1.5 1.5 3 Q (Kvar)_DFIG 2.5 3.5 3 51 22 2.5 2.5 4 3.5 33 4.5 Stator Voltage Frequecy 4 3.5 3.5 44 5 4.5 5 4.5 4.5 55 Q (Kvar)_DFIG 50.5 0 20 Q (Kvar)_DFIG Q (Kvar)_DFIG 50 Stator Frequency Q (Kvar) Q (Kvar) Q (Kvar) Q (Kvar) 3.5 3.5 3.5 20 20 -20 20 20 -20 0 -400 0 0 -20 0.5 1 1.5 2 -40 49.5 49 2.5 48.5 Time -20 -20 48 0 0.5 1 1.5 2 0.5 0.5 -40 -400 0 51 3 33 1 1 1.5 1.5 2 2 Stator Voltage Frequecy 0 2.5 Time 2.5 3 0.5 3 3 2.5 51 Time Time 3.5 1 1.5 3.5 4 2 3.5 3.5 3 4.5 4 4 2.5 4 Rotor Voltage Frequecy 3 4.5 5 3.5 4.5 4.5 5 5 4 4.5 4 4.5 5 5 50.5 50 Rotor Frequency Stator Frequency 50.5 49.5 49 49.5 48.5 48 50 25 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 49 0 0.5 1 1.5 2 2.5 3 3.5 5
  • 26. SOFC Power (KW) Power allocation between Grid, SOFC and Wind - DFIG SOFC Power (KW) 80 60 40 20 0 Load Power (KW) Load Power (KW) 100 50 0 DFIG Power (KW) DFIG Power (KW) 100 50 0 -50 -100 NLL Power (KW) NLL Power (KW) 100 50 0 -50 Grid Power (KW) Grid Power (KW) 200 100 0 -100 -200 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
  • 27. Contd… Percentage THD of Supply voltage and Supply current under balanced / unbalanced linear, nonlinear load Sr no Type of Load % Total Harmonic Distortion 1 2 Balanced Resistive load Va 0.33 Unbalanced Resistive load 0.33 3.23 3 Balanced reactive load 0.33 3.32 0.36 3.35 4 Unbalanced Reactive load ia 3.23 5 Balanced non linear load 0.34 3.53 6 7 Unbalanced nonlinear load 0.37 5.45 3.43 49.74 Balanced nonlinear load without STATCOM 27
  • 28. Conclusions Being the wind energy is intermittent in nature; hybrid system constituting fuel cell; operated in synchronism with wind generator and grid will be the feasible solution. The interfacing of hybrid system with grid should comply the grid code requirements and power quality standards Vector control scheme is very useful for controlling the grid side converter and rotor side converter; the system can work for any change in wind speed. The dc link voltage of converters, rotor speed, and active power and reactive power exchange between machine and grid is almost constant during all operations. The DFIG machine is perfectly synchronised with the SOFC -Grid and any sudden change in the load demand is met by sharing of power as per their rating. With non linear load at PCC, the THD of supply current becomes more than IEEE-519-1992 limit (i.e. THD > 5%), hence D-STATCOM is used to restrict the total harmonic distortion caused by load. Indirect current control scheme using hysteresis controller is useful for controlling of D-STATCOM .  D-STATCOM improves the THD spectrum of source current and voltages; even in the case of any sudden change in nonlinear load. D-STATCOM can be used as a solution to compensate reactive power, neutral current compensation, load balancing and harmonic elimination. Power Factor correction has been done with help of D-STATCOM 28
  • 29. Appendix Parameters of 15 KW, 440 V, 50Hz, DFIG Rs = 0.023 pu, Rr = 0.016 pu, Ls = 0.018 pu, Lr = 0.16 pu, P = 6, J = 0.385 pu Parameters of GSC and RSC Vdc = 830 volt, Cdc = 9200 µF, Kp and Ki (GSC) = 0.83 and 5, Kp and Ki (RSC) = 0.6 and 8, Frequency of the grid-side and rotor-side PWM carrier = 2250 HZ and 1350 Hz SOFC Parameter T = 1273K, Eo = 1.18 Volt, N= 450, Kr = .996*10-6Kmol/(s atm), Uopt = 0.85, KH2 = 8.43*10-4 Kmol/(s atm), KO2 = 2.81*10-4 Kmol/(s atm), KH2O = 2.52*10-3 Kmol/(s atm), ), =26.1s, = 78.3 s, = 2.91 s, R = 0.16Ω, rHO = 1.145 29
  • 30. References 1. 2. 3. 4. 5. 6. 7. 8. 9. Puneet K Goel, Bhim singh, Navin kishore (2010) “Modeling and Control of Autonomous Wind Energy Conversion Sy stem with Doubly Fed Induction Generator” IEEE Int. conf. on Power Electronics, Drives and Energy systems, pp. 18. Bhim singh, Shiv Aggrawal, Tara Chandra Kandpal (2010) “Performance of Wind Energy Conversion System using a Doubly Fed Induction Generator for Maximum Power Point Tracking” IEEE Industry App. Society Annual meeting, pp . 1-7. Vishal Verma, Peeyush Pant, B. Suresh, Bhim Singh (2011) “Decoupled Indirect Current Control of DFIG for Wind E nergy Applications” , IEEE Int. conf. on Power Electronics, pp. 1-6. B. Singh and G. Kasal, (2008) “Voltage and Frequency Controller for a Three-Phase Four-Wire Autonomous Wind E nergy Conversion System” IEEE Transactions on Energy Conversion, Vol 23, No. 2.pp-1170-1177. Raul sarrias, Luis M Fernendez, Carlos A Garcia, Francisco Jurado (2012) “Coordinate operation of power sources i n a doubly-fed induction generator wind turbine/battery hybrid power system ”Journal of Power Sources, Vol.205, 35 4–366. Satish Choudhary, Kanungo Barada Mohanty, Birendra kumar Debta, (2011)“Investigation on Performance of Doubly -Fed Induction Generator Driven by wind turbine under Grid Voltage Fluctuation” IEEE Int. conf. on Environment an d Electrical Engineering, pp.1-4. N P Gupta, Preeti Gupta, Deepika Masand (2012) “Power Quality Improvement Using Hybrid Active Power Filter for A DFIG Based Wind Energy Conversion System” IEEE NUICONE, pp. 1-6. E. Ribeiro, A. J. M. Cardoso, C. Boccaletti (2010) “Grid Interface for a Wind Turbine-Fuel Cell System” IEEE XIX International Conference on Electrical Machines - ICEM, pp. 1-6. Nagasmitha Akkinapragada and Badrul H. Chowdhury (2006)“ SOFC-based Fuel cells for load following Stationary A pplications” IEEE conference, pp. 553-560. 30
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