Page 169 - Renewable Energy Devices and System with Simulations in MATLAB and ANSYS

156 Renewable Energy Devices and Systems with Simulations in MATLAB and ANSYS ®
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TABLE 7.3
Construction Criteria of a Wind Energy Generator

Constructive Criterion PMSG SEIG SCIG DFIG
Technology Fast evolution Proven Proven In evolution
Manufacture Moderate Easy Easy Involving
Acquisition costs Still high Low Low Medium
Adaptability High High High High
Capital return Medium Fast Fast Medium
Commercial availability Low Highest Highest High
Commissioning Medium Minimum Minimum Medium
Specific costs Permanent magnets Overall low Overall low Power converter
Expertise to run Medium Low Low High
OM Low Low Low High
Portability Medium High High Medium
Reliability High High High Top medium
Robustness High High High Medium
Today standardization Low High High Medium
Useful life 20 years 30 years 30 years 15 years
Specific problems PM high cost and easy Demands high Demands high Requires precise
demagnetization at external reactive reactive power slip measurement
high temp. power from grid

TABLE 7.4
Control Criteria of a Wind Energy Generator
Control Criterion PMSG SEIG SCIG DFIG
Active and reactive Full Needs compensation Needs compensation Full
power control
Torque oscillations Flat Wavy Flat Wavy
Controllability Needs voltage boost Difficult for constant Constant speed depends Wide range around
controller speed on power electronics synchronous speed
control
Power factor control Possibly external Not really, variable Not really, variable Allowed
frequency frequency
Speed regulation Total Loose (10% > n s ) Total ±30%
Speed response Fast Slow Slow Fast
against surges
Connectivity Medium Easy Easy Medium
Synchronization for Tight Loose Loose Loose
grid connection
Speed regulation Tight Difficult Difficult Loose