兆瓦级直驱型风力发电系统的效率优化分析

Optimal efficiency analysis of mw_level direct_drive wind generation system

针对兆瓦级永磁直驱风力发电系统,对变流器和发电机效率进行了优化分析.分别建立了中点嵌位式三电平变流器的损耗模型和包括铁损在内的电机损耗模型,通过分析给定转矩下直轴电流与损耗的关系,得到变流器效率最优和发电机效率最优的直轴电流解析式,进而求出永磁同步发电系统整机效率最优解.通过仿真和2 MW三电平背靠背永磁直驱风电变流器的实验样机表明,在不同转矩工作区域内,即可以分别实现变流器效率或发电机效率的最优控制,并能提高发电系统整体效率.

Given the MW-level direct-drive wind generation system, the optimal efficiency of convertersand generators is analyzed. The loss model of the neutral point clamping three-level converters and thegenerators including iron loss is established. Based on the loss model and the voltage, current limit,the converters and generators optimal efficiency analytic expressions of direct current are obtained byanalyzing the relationships of direct current and loss under given torque, and then optimal efficiencysolution of the wind system is got. Finally, simulation and experiment results on a 2MW ＂back toback＂ PWM converter prototype indicate in the fixed torque and speed condition, such optimal effi-ciency control is more efficient than the traditional control strategy not only on the converter or genera-tor efficiency hut also on the wind generation system.