SIMULATION STUDY ON PERMANENT MAGNET WIND POWER GENERATION SYSTEM BASED ON PSIM

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1 SIMULATION STUDY ON PERMANENT MAGNET WIND POWER GENERATION SYSTEM BASED ON PSIM Nan Li 1, Bing YU 2, Lei Liu 1, Bing Kong 2 E.E., State Gri Chengu Electric Power Supply Company, Chengu, Sichuan, China 1 PG Stuent, School of Electrical Engineering an Information, Southwest Petroleum University, Chengu, Sichuan, China 2 ABSTRACT: Through systematically analyzing the mathematical theory knowlege of the small an meium-size irect-rive permanent magnet win power system, this paper has esigne a rate power of 3kW win power system uner the environment of PSIM9.0 software. The win power system moel has been built, the back-to-back ouble- PWM control circuit has been esigne an the simulation analysis has been complete. In the circumstance of win spee changes, the simulation results show that the output power of the generator sie is stable an the DC voltage of the inverter sie is constant, which suggests the correct control strategy, the favorable system stability, an the achieve esign goal. The work alreay one in this article provies a goo platform an infrastructure for systematically analyzing the small an meium-size win power system. Keywors: PSIM; win power system; PMSG; full power converter; simulation analysis. I.INTRODUCTION With the increasing epletion of fossil energy, an the continuing eterioration of global environment, the win power generation, as one kin of new energy power generations, has been pai further attention by the governments an researchers with its uniue avantages. Recently, along with the small an meium-size inepenent power generation achieving strong support by the relevant national policies, small an meium-size win turbines have been vigorously promote an applie [1]. It is mainly use in remote areas where there is win but no electricity an it is use as the self-provie power plant by some enterprises, such as remote regions, borer posts, lonely islans, largescale agriculture, animal husbanry, fisheries an oil fiels, etc. Therefore, the research on small an meium-size win turbine system has great significance. The irect-rive permanent magnet win turbine system is a research hotspot in recent years, an the permanent magnet synchronous generator (PMSG) has been wiely use with its goo control precision, high efficiency, low maintenance an many other avantages. Stuy in this paper is base on PSIM9.0 simulation software. PSIM9.0 is a eicate simulation software for power electronics an motor control stuy, it has the main features of user interface simple, learning an unerstaning easy, operation convenient, simulation fast, simulation waveforms clear an intuitive, etc [2]. Compare to the previous version, PSIM9.0 has newly ae the solar cell moel an win turbine moule which are relate to the new energy power generation, thereby proviing a superior platform for win power generation system esign an analysis in this article. Utilizing MATLAB/Simulink an PSCAD/EMTDC respectively, literature [3] an [4] have complete the WECS relate research work. These two softwares are so powerful that they can realize the complex simulation analysis, however, they launch slowly, have longer simulation time an more complex component moules an control loops while compare with PSIM. Although the simulation software in literature [5] has perfect function, it is not universal an it is not suitable for wiesprea utilization. Literature [6] an [7] have establishe the permanent magnet synchronous motor (PMSM) control system simulation moel an Maximum Power Point Tracking (MPPT) control system moel of WECS respectively, but they i not establish complete WECS moels an o simulation analysis. Using PSIM software which can be use to buil the simulation system moel uickly an intuitively, this paper has set Copyright to IJAREEIE

2 up a system moel an finishe the small an meium-size win power system simulation, an the generator spee an gri voltage being controlle accurately has been realize, which provies new ieas for WECS researches. II. PERMANENT MAGNET WIND POWER GENERATION SYSTEM OVERVIEW Win power generation system consists of win turbine, PMSG, converter an control system, the basic structure is shown in Fig.1. Differ from traitional asynchronous win power generator system, PMSG system eliminates the nee for heavy overrive gearbox, which improves the reliability of power plant operation an the efficiency of win energy utilization. Moreover, PMSG system absorbing reactive power barely from the power gri an full-power converter achieving low voltage rie through (LVRT) provie a reliable guarantee for the increasingly stringent win power integration emans. In short, the irect-rive permanent magnet win power generation system has the following salient features [8] : 1) Light weight an small size generator; 2) Small electromagnetic interference an goo electromagnetic compatibility; 3) Simple structure, high reliability an long service life; 4) High efficiency an significant energy saving effect; 5)Goo social aaptability uner harsh environments; 6)Goo voltage waveform uality an aaptable to a variety of loa changing circumstances. Fig.1 Permanent magnet win power generation system block iagram III. WIDN POWER GENERATION SYSTEM MATHEMATIC MODEL 3.1 Power Characteristics of Win Turbine Win turbine is a key part of the whole win energy conversion system, its main function is to capture win energy an converter it to the mechanical kinetic energy effectively. So, win turbine not only affects the output efficiency an stability of the entire win power generation system, but also irectly etermines the system operation status. Accoring to flui mechanics knowlege, the kinetic energy prouce by airflow sweeping win turbine is the input power of the win turbine, which can be expresse as follows E mv Sv (1) 2 2 Where, m is the air uality, S is the swept area of blaes, v is the win spee, ρ is the air ensity. Accoring to Betz limit theory [9], the maximum power that the win turbine can export theoretically is shown in the following euation (2). 1 3 Pmax EC p max v SC p (2) max 2 Where, C is eual to 0.593, however, in the actual operation, it is almost impossible to achieve the value an is p max generally taken to be 0.4. The output torue formula of win turbine can be expresse as follows. P 1 3 Tm v S C p (3) 2 Where, P is the output power, C is the power conversion factor an ω is the angular velocity of win turbine blae rotation. 3.2 Permanent Magnet Synchronous Generator Moel p During the operation process of PMSG, the rotor an stator keep a relative movement state, an there are mutual influences between winings an permanent magnet an winings. Couple with the nonlinear factors such as Copyright to IJAREEIE

3 magnetic circuit saturation, the electromagnetic relation is very complicate. Hence, it is ifficult to establish accurate mathematical moel of PMSG. Therefore, in orer to facilitate analysis, the following assumptions are mae: 1) Y- connecte stator winings; 2)Sinusoial back-emf, no consiering the effect of space harmonic an magnetic circuit saturation; 3)Excluing ey current an hysteresis losses; 4)No ynamic response process of excitation current. In the - axis rotation coorinate system,the voltage an electromagnetic torue mathematical relationships of PMSG are expresse as follows [10]. V c ( Rs pl ) i (4) V c ( Rs pl ) i Li f (5) Li 3 Te np[ f i ( L L ) ii ](6) 2 Where, an are the stator flux linkages corresponing to -axis an -axis respectively, L an L are the twophase stator winings self-inuctances corresponing to -axis an -axis, armature currents for -axis an -axis respectively, symbol, n is the motor pole pairs, f Rs is the stator resistance, i an i are the c is the rotor rotating angular spee, p is the ifferential operator is the permanent magnet flux linkage an it is a constant. IV. CONTROL STRATEGIES AND MODELING Back-to-back ouble PWM full power converter consists of generator sie converter, DC link an gri sie inverter. The generator sie converter receives active power firstly, then this part of active power is sent to the gri sie converter through the DC link an finally to the gri. Due to the spee of win an generator changes unceasingly, the output of generator voltage an freuency varies, so, in orer to achieve gri voltage an freuency reuirements, control metho of ual PWM converter is the key. 4.1 Control Strategy an Simulation Moel of Generator Sie The purpose of generator sie converter control while win spee changes, is to regulate the generator torue an rotating spee, an achieve maximum power tracking control. In the rotating coorinates, as formula (6) shows, when L L, torue is only relate to -axis current, therefore, the torue control is eual to current control. In short, the control strategy of generator sie is ouble close loop control which puts the current control as inner loop control an the spee control as the outer loop control. During the control process, the torue an rotating spee epens on the size of the space vector current, through controlling i an i, the actual i an i track the control signal i an i, then the control objective is achieve. The simulation moel uner PSIM simulation environment is shown in Fig.2. Copyright to IJAREEIE

4 Fig.2 Generator sie rectifier control moel 4.2 Control Strategy an Simulation Moel of Gri Sie The gri-sie three-phase voltage converter in fact is the rectifier which works in inverter state, controlling the inverter makes DC bus voltage stability an gri-sie unit power factor operation. Traitional small an meium-size win power system is controlle by single current control metho, aiming at the shortcomings of the metho, this paper aopts ouble close-loop controlle voltage oriente vector control metho [11]. Voltage oriente vector control is ivie into inirect control metho an irect control metho, this paper aopts the latter which has a better ynamic performance, incluing close-loop current control, uick current response an goo robustness [12-13]. In the control process, the outer loop voltage signal is affecte by the given DC voltage signalv an the feeback DC voltage signal V c, while the inner loop current signal is controlle by the coorinate transforme current on the gri sie. The simulation moel built utilizing PSIM software is shown in Fig.3. c Fig.3 Gri-sie inverter control system moel Copyright to IJAREEIE

5 V. SIMULATION RESULTS ANALYSIS In orer to verify the feasibility of the small an meium-size permanent magnet win power system, a rate power of 3kW system has been esigne, the main parameters of this system is shown in Tab.1. The simulation system moel is built utilizing PSIM9.0 software, an the simulation time is set to be 0.5s. When win spee mutates, in orer to verify the system characteristics of maintaining stable operation, it is set from the rate win spee of 12m/s to 9m/s, the waveform is shown in Fig.4. At this point, the actual change of generator spee an electromagnetic torue is shown in Fig.5. Fig.6 expresses the output power waveform when the win spee changes, while Fig.7 shows the DC voltage waveform. Fig.8 an Fig.9 inicate the output line-voltage value an the three-phase current value respectively, while Fig.10 illustrates the gri reference voltage. Tab. 1 Parameter List of Win Energy System Items Parameter Values Air ensity 1.2kg/m 3 Blae raius 2m Rate win spee 12m/s Win turbine power rating 3kW Phase voltage 180V Gri freuency 50Hz Converter switching freuency 10kHZ DC bus voltage 400V DC bus capacitance value 1.9mF Fig.4 Step Change of Win Spee Fig.5 Generator Spee an Torue Wave Changes Copyright to IJAREEIE

6 Fig.6 Generator Output Active Power Fig.7 DC Voltage Waveform Fig.8 Inverter Output Voltage before the Filter Fig.9 Output Current Waveform Copyright to IJAREEIE

7 Fig.10 Inverter Output Voltage Reference Value The pitch angle transformation is not consiere in this paper, an the system is operate uner or below rate win spee. Referring to Fig.5, when the win spee ecreases, the generator spee an the electromagnetic torue ecreases accoringly, the response spee is very fast for the signal keeps stability after tiny fluctuations. Especially, from Fig.6, the output power signal keeps steay after win spee changes, which fully meets the reuirements of the control system. The gri sie DC voltage is a critical parameter which etermines whether WECS can incorporate into the power gri or not. In Fig.6, the DC voltage signal transits smooth an recovers uickly an it won t cause big impact an interference to power gri, which satisfies the power gri reuirements. The inverter output voltage an current signals in Fig.8 an Fig.9 are goo for there are almost no harmonics. In a wor, the simulation result inicates that the simulation effect uner PSIM environment is goo an the output parameters are very stanar. At the same time, it emonstrates the system is reasonable an satisfies the esign reuirements. VI.CONCLUSIONS The simulation moel of small an meium-size permanent magnet win power generation system has been esigne base on PSIM9.0, each moule parameters has been calculate accurately. The final simulation results are in conformity with the theoretical calculation values, showing that the moel esign of the small an meium-size permanent magnet power generation system is reasonable. In PSIM software environment, the system moel is clear an intuitive, the control circuit is simple, the simulation waveform is easy analytical, which provies the experimental an investigative basis for small an meium-size win power generation. REFERENCES [1] D. F. Li, 2012 Small an Meium-size Win Power Inustry Development Report, Win Energy, vol.5, pp , [2] PSIM9.0 User's Guie, 2010, [3] J. Guo, Y. P. Zhang, Gri-connecte Operation Simulation of Direct-rive Permanent Magnet Synchronous Win Power System, Chinese Journal of Power Sources, vol. 37, no. 4, pp , [4] Q. R. Tu, Z. Xu, J. Zhang, Access System of Direct-rive Win Power Moeling an Simulating Base on PSCAD/EMTDC, Acta Energiae Solaris Sinica, vol. 31, no. 4, pp , [5] D. S. Zheng, H. Luo, Y. Cao, et al., The Control System Design an Implementation of Double-Fe Win Power Converter Base on LabVIEW, Electric Drive, vol. 43, no. 9, pp , [6] Z. C. Ji, H. Zhou, S. D. Li, PSIM-Base Moeling an Simulation of Permanent Magnet Synchronous Motor Vector Control System, Journal of System Simulation, vol. 16, no. 5, pp , [7] K. H. Kim, T. L. Van, D. C. Lee, et al., Maximum Output Power Tracking Control in Variable-Spee Win Turbine Systems Consiering Rotor Inertial Power, IEEE Trans. Inustrial Electronics, vol. 60, no. 8, pp , [8] D. S. Oliveira, M. M. Reis, et al., A Three-Phase High Freuency Semi-Controlle Rectifier For PM WECS, IEEE Trans. Power Electronics, vol. 25, no. 3, pp , [9] V. Agarwal, R. K. Aggarwal, P. Patiar, et al., A Novel Scheme for Rapi Tracking of Maximum Power Point in Win Energy Generation Systems, IEEE Trans. Energy Conversion, vol. 25, no. 1, pp , [10] M. Chinchilla, S. Arnaltes, J. C. Burgos, Control of Permanent-Magnet Generators Applie to Variable-Spee Win-Energy Systems Connecte to the Gri, IEEE Trans. Energy Conversion, vol. 21, no. 1, pp , [11] J. J. Zhang, C. X. Zhang, Y. B. Che, Gri Inverter System Analysis of Small Win Power Generation, Electric Drive, vol. 43, no. 7, pp , [12] J. Yao, Y. Liao, H. Li, et al., Unity Power Factor Control of Direct-rive Permanent Magnet Synchronous Generator, Electric Machines an Control, vol. 14, no. 6, pp , [13] Arifujjaman M. Moeling Simulation an Control of Gri Connecte Permanent Magnet Generator (PMG)-Base Small Win Energy Conversion System[C]//IEEE Electric Power an Energy Conference,2010:1-6. Copyright to IJAREEIE

8 BIOGRAPHY Li Nan is an electrical engineer in the State Gri Chengu Electric Power Supply Company, Sichuan, China. He obtaine his Master egree of Electrical Engineering from the University of Electronic Science an Technology of China (UESTC) in Yu Bing is a postgrauate stuent in South West Petroleum University, Sichuan, China. His research areas of interest inclue Stuy of Win Power Generation System Control an Simulation, Offshore Win Power Micro-gri Voltage an Freuency Control. Liu Lei is an assistant engineer in the State Gri Chengu Electric Power Supply Company, Sichuan, China. He obtaine his bachelor egree of aministration from North China Electric Power University (NCEPU) in Copyright to IJAREEIE