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Wind Energy Projects

Wind energy

is a form of solar energy. Wind energy describes the process by which wind is used to generate electricity. Wind turbines convert the kinetic energy in the wind into mechanical power. A generator can convert mechanical power into electricity.

Wind is caused by the uneven heating of the atmosphere by the sun, variations in the earth’s surface, and rotation of the earth. Mountains, bodies of water, and vegetation all influence wind flow patterns[2], [3]. Wind turbines convert the energy in wind to electricity by rotating propeller-like blades around a rotor. The rotor turns the drive shaft, which turns an electric generator. Three key factors affect the amount of energy a turbine can harness from the wind: wind speed, air density, and swept area.

Equation for Wind Power

P = {1\over2} \rho A V^3

  • Wind speed
The amount of energy in the wind varies with the cube of the wind speed. In other words, if the wind speed doubles, there is eight times more energy in the wind ( 2^3 = 2 x 2 x 2 = 8). Small changes in wind speed have a large impact on the amount of power available in the wind [5].
  • Density of the air
The more dense the air, the more energy received by the turbine. Air density varies with elevation and temperature. Air is less dense at higher elevations than at sea level, and warm air is less dense than cold air. All else being equal, turbines will produce more power at lower elevations and in locations with cooler average temperatures[5].
  • Swept area of the turbine
The larger the swept area (the size of the area through which the rotor spins), the more power the turbine can capture from the wind. Since swept area is  A = pi r^2 , where r = radius of the rotor, a small increase in blade length results in a larger increase in the power available to the turbine

 

FPGA-Based Predictive Sliding Mode Controller Of A Three-Phase Inverter

This paper proposed a novel predictive variable structure- switching-based current controller for a three-phase load driven by a power inverter. The design specifications are robustness to load electrical parameters, fast dynamic response, reduced switching frequency, and simple hardware implementation. In order to meet previous specifications, a sliding mode controller has 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 transition diagram provides for a minimum number of switches by the three-phase inverter that is confirmed through simulation and experimental results. Its regulation using the proposed control law provides good transient response by the brushless ac motor control. However, this does not limit the wider applicability of the proposed controller that is suitable for different types of ac loads (rectifier and inverter) and acmotors (induction, synchronous, and reluctance). A new logical FPGA torque and speed controller is developed, analyzed, and experimentally verified.

Keywords

1. Brushless alternating-current (BLAC) motor
2. field-programmable gate array (FPGA)
3. finite-state machine (FSM)
4. predictive control
5. sliding mode controller (SMC)
6. supervisor
Software: Matlab/Simulink

Block Diagram:

Basic Circuit Of A VSI.

Fig.1. Basic Circuit Of A VSI.

References

[1] M. P. Kazmierkowski, R. Krishnan, F. Blaabjerg, and J. D. Irwin, Control in Power Electronics: Selected Problems. New York: Academic, 2002.
[2] R. Kennel, A. Linder, and M. Linke, “Generalized predictive control (GPC)—Ready for use in drive applications?” in Proc. IEEE Power Electron. Spec. Conf., 2001, vol. 4, pp. 1839–1844.
[3] A. Malinowski and H. Yu, “Comparison of embedded system design for industrial applications,” IEEE Trans. Ind. Informat., vol. 7, no. 2, pp. 244– 254, May 2011.
[4] C. Buccella, C. Cecati, and H. Latafat, “Digital control of power converters—A survey,” IEEE Trans. Ind. Informat., vol. 8, no. 3, pp. 437– 447, Aug. 2012.
[5] E. Monmasson and M. N. Cirstea, “FPGA design methodology for industrial control systems—A review,” IEEE Trans. Ind. Electron., vol. 54, no. 4, pp. 1824–1842, Apr. 2007.
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