1.
1 March 2006
Development and Test of a 5 kW Wind Turbine for Modular Autonomous Supply Systems
Berthold Hahn Paul Kühn
Institut für Solare Energieversorgungstechnik (ISET), Division Information and Energy Economy Kassel, Germany  

2. Development of a small wind turbine for the modular system technology
Development of a small wind turbine for the modular system technology
Supported by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety
Development and design of mechanical components
Grid parallel pilot operation
ISET
Wind-test
Testing within an autonomous supply system
aerodyn
SMA
Micro-wind
Concept study and
market analysis
Uni
Stuttgart
Uni
Kassel
Project management
and development of
the control unit
Airfoil analysis
Development of the generator

3.
Background
Modular system technology provides smart, customised decentral power supply systems, but up to now no appropriate wind turbine.
 new development neccessary
 intense cost pressure
Objective
Development of a small wind turbine that is compatible with modular electrical power systems and near to the price level of large wind turbines.
 retail price < 2000 € / kW

4. Approach Outcome Integrated design concept, 
Approach
Outcome
Integrated design concept, 
load-bearing casing, passive yaw control
State of the art control unit 
(grid connection, monitoring and remote control)
Simple electrical concept with  specially designed generator
Rotor blades which are easy to  manufacture
Fully enclosed nacelle protects all parts against corrosion and external media, weight and cost reduction,
downwind turbine with free yaw
No additional features needed when operating in autonomos supply systems, cost reduction
Compatibility with modular power supply systems and conventional electrical grids, increased efficiency, cost reduction
Significant cost reduction with little loss in efficiency

5. Technical data aeroSmart5
Technical data aeroSmart5
Asynchronous Generator, 2-levels
Nominal Power:
5,0 kW
Wind Speed
Cut in:
Nominal:
Max. Survival:
3,5 m/s
13,5 m/s
65 m/s
Power Control:
Passive-Stall
Yaw:
Downwind with Free Yaw
Number of Blades: 3
Rotor Diameter:
5,1 m
Weight Nacelle with Rotor:
141 kg
Brake System:
Electromagnetic Safety Brake
Redundant Mechanical Brake
source: aerodyn
Rotor blades:
Pultruded glass fibre reinforced plastic (GRP) High lift to drag ratio
Constant airfoil section throughout the length
Not twisted, fixed angle throughout the length

6. Measurements (1 Hz and 60 Hz):
aeroSmart5 with Control Unit
PV-Moduls with Inverters
Battery Inverters and Battery
Diesel Generator
Loads
Setup of the system
Measurements (1 Hz and 60 Hz):
Prototype of the aeroSmart5 at the ISET test facility „Alte Schanze“
Meteorological parameters at hub height
Electrical current, voltage and power of all system components
Yaw orientation, tower acceleration...
AC-Bus

7. Tests focus on... ● Optimisation of the control system
Tests focus on...
● Optimisation of the control system
reactive power compensation
hysteresis loop switching between generator stages
stepping procedure between generator stages
brake control
● Operation of different system configurations with special emphasis on analysis of interaction between wind turbine and battery inverters
● Reaction and stability of the yaw system under turbulent wind conditions
● Investigation of dynamic processes
oscillations of nacelle and tower
dynamic behaviour of electrical properties
fluctuation of electrical power under influence of stall effect

8. Battery charging effects
...
Battery charging effects
Battery current
Set value for charging voltage
Charging voltage
Alte Schanze – system configuration with two dump loads (1 kW and 5 kW)
1-min-average,

9. aeroSmart5 measured power curve
aeroSmart5 measured power curve
Alte Schanze, 10-min-data: to

10.
Outlook
● Optimisation of interaction between wind turbine and hybrid power system  improvement of battery charge process
● Test of single-phase model (60 Hz) for the US-American market
● Launch in 2007
● Development of a 10 kW model