Type: Research Essays
Sample donated: Owen Gibbs
Last updated: February 15, 2019
Abstract: In this paper, Simulation Model forAnalysis of Permanent Magnet Synchronous Generator (PMSG) based Wind TurbineGeneration System is designed in MATLAB / SIMULINK software. The developedmodel is simulated and analyzed with step response (increase/decrease) of windspeed applied to PMSG.
It has been observed that PMSG output responds similarto the change in wind speed applied to the wind turbine controller. It has been observed that PMSG output responds similarto the changes in wind speed. The wind turbine controller generates mechanicaltorque/power (N-m) with respect of the wind speed. Mechanical torque/power usedto drive PMSG is shown in MATLAB / SIMULINK Model. Keywords: Wind Turbine, PMSG, Perturb &Observe, Incremental Conductance1. Introduction: Access to electricity is now a basicrequirement of mankind.
There are still many places around the world which haveno access to electricity. International agencies report that 1.5 billion peoplehave no access to electricity, which is more than 20% of world’s population.Even though many of these places might have substantial potential for energygeneration, the resources are not properly identi?ed and/or utilized. Hence,people have to pay at high rates, if they have the ?nancial resources, for the standardenergy sources to full?ll their basic energy requirements such as lighting,charging small equipment like radios and mobile phones, and even heating. Inmany remote places, people often burn kerosene and even wood for basic lightingand heating. Meanwhile, there is a big contradiction between the fossil fuels supplyand the global energy demand, which leads to a high oil price in theinternational market recently.
The energy shortage and the atmosphere pollutionhave been the major limitations for the human development. Generation ofelectricity through renewable energy sources such as solar, wind, andmicro-hydro could be potential options for these remote places. For anisolated, o?-grid and stand-alone system, the energy needs to be stored wheneveravailable from these sources and then supplied if required. In hilly and remoteregions where renewable energy potential is high, large scale generatingsystems could also be an option, but due to the complex geography and di?cult infrastructure, small scale systems mightseem more feasible. 1.
1 Current research activities: Electricity is one themost essential needs for humans in the present. Use of electricity isincreasing day by day. The electricity finds its application in all the domains.The rapid increase in the demand for electricity and the recent change in theenvironmental conditions such as global warming led to a need for a new sourceof energy that is cheaper and sustainable with less carbon emissions. Among allrenewable energy resources, wind energy conversion technology has greatlyincreased in the past for improvement of power crisis and global warming issuesin the world.1.2 Problem Overview: The energy from theserenewable/natural sources tends to vary throughout the day and hence optimizingthe energy capture is a necessity.
For a wind turbines, Photo-Voltaic (PV)arrays, and micro-hydro turbines, the output power is determined by the wind speed, irradiation and water ?owrespectively. Hence, the control of these systems needs to behave appropriatelyaccording to the variation of these parameters. For example, the turbine speedfor wind and micro-hydro needs to be adjusted for deferent wind speeds or water?ow such that the generated power available is optimized and the system runs atMaximum Power Point (MPP). Similarly, the output DC voltage and current of thePV array systems need to be adjusted in order to run them at MPP.
2. Wind Turbine GenerationSystem Connected to Grid: Wind turbine is connected to PMSG from where we getthe voltage, current and power which will be converted into the pulsating DCwith the help of a rectifier. The output of the rectifier i.e. current, voltageand power will be given to the DC-DC Converter where we get the output voltage,current and power. Theinerter is used to convert the DC into AC which will show the output results inAC. The controller is used to control the inerter which is connected to theload. Fig.
1 Wind Turbine Generation System Connected toGrid 3. ControlMethodologies:3.1 DC-DC Converter: It is an electronic devicethat converts a source of direct current from one DC voltage to another. Herewe are using Boost converter with and without MPPT techniques and obtaining thepower accordingly. The output of the rectifieris given as an input to DC-DC Converter as shown in above fig.1. The inductoris connected from the input supply to the common node between the MOSFET anddiode.
Therefore the peak MOSFET current is now nearly equal to the inputcurrent, not the load current. Theinductor and MOSFET current in CCM. If we ignore the small triangular ripple,it is easy to see that the peak MOSFET current is nearly the same as the loadcurrent.
Boostregulators have a maximum duty cycle, beyond which the regulator will not boostas shown in graph: MPPT Control TrajectorySubjected to Step Input: The experiment began by starting up the wind turbinesimulator at a wind speed of 4.5m/s to verify the tracking performance of thedeveloped MPPT controller. The controller would try to track the maximum peakpower as fast as possible by reducing Pe and thus resulting in an increase inwt . When an operating point with the maximum power was found (i.e., dp/dw =0),the controller tried to keep staying at that point.
The objective of thisexperiment was to track the maximum output power of the turbine. The windsimulator was started at a wind speed of 4m/s, stepped up to 4.5, 5 and 6 m/srespectively and run until steady state. The MPPT controller would capturemaximum powers of 260, 420, 600 and 900 W respectively.
The power versus rotationalspeed is shown and the output torque versus rotational speed is shown. It isclearly seen that at the maximum output power, the aerodynamic torque are not maximum.The relationship between cP and time obtained from the experiment. It can beseen from the figure that in this case, the MPPT controller can manage to keepcP at 0.4 for the four step wind speeds. 3.2 Maximum power transferred toload is analysed using two control methods: · Perturb & Observe Algorithm· Incremental Conductance Algorithm Perturb & Observe: In thismethod controller adjusts the voltage by a small amount from the turbine andmeasures power, if the power increases, further adjustments in that directionis needed until power no longer increases.
This is called the perturb & observemethod. It depends on the rise of cure of power against voltage below maximumpower point. The following parameters are usedfor the above algorithm