21-12-2012, 12:22 PM
MICRO WIND POWER GENERATOR WITH BATTERYENERGY STORAGE FOR CRITICAL LOAD
MICRO WIND POWER.pptx (Size: 2.69 MB / Downloads: 61)
INTRODUCTION
Traditional energy sources.
Importance of micro wind power generation.
Sensitive electronic components and critical loads needs good quality power.
Power quality of micro wind power generation.
Lead acid battery cell for energy storage.
Energy saving and un-interruptible power.
Current controlled voltage source inverter is used for the interfacing between battery with microwind generator into the distributed netwok.
Advantages
Unity power factor and power quality.
Real and reactive power support.
Stand-alone operation in case of grid failure.
Harmonics reduction.
Reduction in CO2 production.
Control Scheme of the System
Dc link to extract energy from wind
Ripples are avoided by using dc link
Step up transformer and bridge rectifier for dc bus voltage
Battery with micro-wind generator for critical load application
The control scheme is based on injecting the current into the grid using “hysteresis current controller.”
The reference current i∗Sabc and actual current iSabc is measured from source phase a, b, c are compared and thus activate the operation of inverter
Why Hysteresis Band Controller?
The source currents are harmonic free and their phase-angles are in-phase with respect to source voltage.
The power transfer takes place as soon as battery energy system is fully charged.
Hysteresis band current control is not expensive.
The control is excellent for a fast response of an inverter to rapid changes of reference current.
PI Controller
It corrects the error between measured variable and set value.
Kp amplify the current error and Ki process the corrected error.
Kp improves steady state accuracy, relative stability and also makes the system less sensitive to the parameter variations.
Fast response
The input clock for the circuit
The output of the hysteresis band current controller act as the input clock to this circuit.
IC 74123 is used to generate the time delay.
The pulse duration is controlled by the selection of external resistance and capacitor values.
Dead time in order to prevent short circuits
CONCLUSION
Exchange of real and reactive power support to the critical load.
The hysteresis current controller is used to generate the switching signal for inverter in such a way that to cancel the harmonic current in the system.
The scheme maintains unity power factors.
Allow the real power flow during the instantaneous demand of the load.
Rapid injection or absorption of reactive/real power flow in the power system