17-08-2012, 01:49 PM
Design and Implementation of Power Converters for Wind Energy Conversion System
Abstract
This paper presents the design and
implementation of power converters for wind conversion
systems. The power converter can not only transfer the power
from a wind generator, but also improve the stability and
safety of the system. The proposed system consists of a
permanent magnet synchronous generator (PMSG), a DC/DC
boost converter, a bi-directional DC/DC converter and a
full-bridge DC/AC inverter. The wind generator is the main
power source of the system, and the battery is used for energy
storage and power compensation to recover the natural
irregularity of the wind power. In order to keep producing to
the maximum power output from the wind power generator, a
digital signal processor (TMS320LF2407A) is used to realize
the system controller. Finally, a 200W wind energy conversion
system is built and experimental results are provided to verify
the theoretical analysis and feasibility of a wind power
generator system.
INTRODUCTION
Wind energy, one of the most effective power
technologies is ready today for global deployment on a scale.
Wind power can be installed far quicker than the
conventional power stations. It is safe, clean, and abundant.
Unlike conventional fuels, wind energy is a massive
indigenous power source and is permanently available in
virtually every nation in the world.
Wind Force 12 is a global industry blueprint which
demonstrates that there are no technical, economic or
resource barriers to supply 12% of the world's electricity
needs with the wind power alone by 2020 - and this is
against the challenging backdrop of a projected two thirds
increase of the electricity demand by that date[1]. The wind
industry of today is one of the world's fastest growing
energy sectors and offers the best opportunity to begin the
transition to a global economy based on the sustainable
energy.
TOPOLOGIES AND CONTROL STRATEGIES OF THE
PROPOSED SYSTEM
Topologies
The circuit diagram of the proposed system is shown in
Fig. 4. The system structure contains the boost DC/DC
converter, the full-bridge DC/DC inverter and bi-directional
DC/DC converter. The function of boost DC/DC converter
is to raise the DC input voltage to a higher and fixed voltage
level. The output DC voltage of the boost converter is
delivered to the full-bridge DC/AC inverter, and provides
the energy for battery charging as the WG generates enough
power. Moreover, the battery discharges through the
bi-directional DC/DC converter to provide power
compensation when the WG output is less than the load
capacity.
CONCLUSION
A 200 W system which composes of power converters
for wind generator with the proposed control method has
been constructed. Experimental results show that the
flexible control strategy is able to make the converters
operating with high performance. The multi-stage current
charging method is used to charge the batteries and the
output power of wind generator is increased by the MPPT
algorithm. At various wind speeds, the system can use the
battery for energy storage or power compensation to keep
the load voltage and load current stable.