风力异步电动机_中英文翻译_毕业论文(18)

毕业论文,开题报告。

component of vrdqs. The (Lm/Ls)ωsfλsq term contributes to vrds; the term is approximately zero due to the orientation frame. The (Lm/Ls)ωsfλsd term dominates the vrqs component. The shape of the (Lm/Ls)ωsfλsd component is clearly influenced by ωsf.

5. DISCUSSION

This analysis enables the vrds and vrqs components to be characterised by the dominant terms. The λs orientation frame results in the λsq feed forward term in vrds being negligible and so the steady state vrds component is a result of Rrsirds σωsfirqs. Three distinct regions can then be identified, sub-synchronous speed (low irqs due to low load so vrds is approximately Rrsirds), about synchronous speed (ωsf is around 0 so vrds is approximately Rrsirds) and supersynchronous speed (irds and irqs are comparable due to higher load torque and high stator power factor so vrds is approximately Rrsirds σωsfirqs). The transient response of vrds for a step in irds* is dominated by the pσirds. The p(Lm/Ls)λsd term has a negligible effect as the λsd term is constant assuming a stiff grid. An irds* step affects both the steady state value of vrqs and the steady state terms in vrds.

The steady state vrqs component is dominated by the λsd term, confirmed by Hopfensperger et al [9] (with the exception of synchronous speed when the steady state vrqs is dependent on the Rrsirqs term). The transient response of vrqs to an irqs* step is dominated by the pσirqs term as the differential of the step change in irqs is initially high.The p(Lm/Ls)λsq term has a negligible effect as λsq is approximately zero. The vrds term and the steady-state terms in vrqs all experience a change in value due to the irqs* step.

6. CONCLUSIONS

This paper has investigated the controller response for the DF and IG mode connections for a 2 MW DFIG wind turbine. The machine parameters for the 2 MW machine were provided, for a commercially available WRIM used in wind turbines, by the manufacturer. The 2 MW machine parameters used in this work are not simply a linear scaling of prior work on a 7.5 kW machine and so the characteristics are not identical between the two machines. Two areas of analysis have been investigated with respect to the 2 MW DFIG. Existing simulation models have been used to evaluate the controllability and steady-state and transient behaviour of a 2 MW DFIG in DF and IG mode. The outcome shows that IG mode is a controllable mode of operation which will extend the low speed operation as rotor voltage decreases (as speed reduces) and so the voltage limit of the IGBTs will be respected as will the current and power limits of the machine and converter. The composition of the rotor voltage was

investigated in DF mode for the 2 MW DFIG. This showed how the importance of the decoupling equations on the performance of the DFIG varied with speed.

ACKNOWLEDGEMENTS

The authors are grateful to FKI Industrial Drives and the EPSRC for their support.

REFERENCES

1. Pena R, Clare J and Asher GM. Doubly Fed Induction Generator using Back-to-Back PWM Converters and its Application to Variable-Speed Wind-Energy Generation. IEE Proceedings - Electric Power Applications May 1996; 143; 3; 231–241.

2. Kelber C and Schumacher W. Control of Doubly-Fed Induction Machines as an Adjustable Speed

Motor/Generator, VSSHy 2000 - European Conference Variable Speed in Small Hydro.

3. Ran L, Bumby JR and Tavner PJ. Use of Turbine Inertia for Power Smoothing of Wind Turbines with a DFIG. 11th International Conference on Harmonics and Quality of Power 2004; 106–111.

4. Müller S, Deicke M and De Doncker RW. Doubly fed induction generator systems for wind turbines. IEEE Industry Applications Magazine 2002; May/June; 26–33.

5. Hansen AD, Iov F, Blaaberg F and Hansen LH. Review of Contemporary Wind Turbine Concepts and their Market Penetration. Wind Engineering 2004; 28; 3; 247–263.

搜索“diyifanwen.net”或“第一范文网”即可找到本站免费阅读全部范文。收藏本站方便下次阅读，第一范文网，提供最新人文社科风力异步电动机_中英文翻译_毕业论文(18)全文阅读和word下载服务。