一种新型离网型永磁风力发电机级联整流装置研究

Novel cascade rectifier device of off-grid type wind power generation

针对偏远地区原有的离网型风力发电系统亟需扩容的问题,提出了一种新型的共直流母线级联整流装置,通过该装置可实现两台发电机同时发电运行。对该新型级联整流装置的拓扑结构、发电机电流换相过程、占空比计算方法等内容进行了研究,建立了发电机转速与不控整流电路输出平均电压之间的关系,对两发电机串、并联运行状态进行了详细分析归纳,提出基于滞环原理的状态切换方法,并在Matlab仿真平台上对系统进行了仿真验证。研究结果表明,该装置可以根据不同的发电机转速,改变两台发电机间的工作方式,扩展发电机调速范围,有效增加系统容量;同时可使功率开关器件占空比运行于合理范围内,避免窄脉冲的出现,减小高次谐波,改善系统性能。

Aiming at the problem that the original off-grid type wind power generation systems in some remote areas were in urgent need of expansion,a novel common DC bus cascade rectifier device was proposed,and the simultaneous parallel operation of two generators can be achieved based on the device. The topological structure of the novel cascade rectifier device,the commutation process of the generator＇s current,and the computing method of duty cycle were studied. The relationship between the speed of generator and the output average voltage of uncontrolled rectifying circuit was established. The operating states in series or in parallel of the two generators were analyzed and concluded in detail. Meanwhile,the switching method of state based on the hysteresis loop principle was proposed. In addition,the system was verified by simulation using Matlab. The results indicate that the device can change the working modes of the two generators according to the different speed of the generators,expand the speed adjustable range of generators and increase the capacity of system effectively,at the same time,the device allows that the duty cycle of power switching device operates in the reasonable range,avoids the occurrence of narrow pulse,decreases the high-order harmonics and improves the system performance.