适用于全桥型模块化多电平换流器的直流融冰装置控制策略

发布时间：2018-07-29 16:27

【摘要】：现有直流融冰装置采用了晶闸管可控整流技术,在运行中均会消耗一定的无功功率,产生特征次谐波,对交流系统带来一定影响。全桥型模块化多电平换流器(MMC)具有直流电压和直流电流双向运行能力,可满足直流融冰对换流器运行工况的要求。文中提出了适用于全桥型MMC的直流融冰装置控制策略。首先,对全桥型MMC直流融冰装置的主回路拓扑的运行原理进行了介绍,并给出了适用于全桥型MMC的调制比定义。其次,充分利用全桥型子模块可输出正、零、负模块电压的特点,分析如何实现零起升压/升流,以满足不同类型、长度线路的融冰需求,使得直流电压很低时,交流侧仍然保持很高的电能质量。然后,基于无功补偿容量、设备利用率和器件裕度等对装置的无功补偿进行研究,确定了装置无功补偿模式的拓扑结构。最后,在PSCAD/EMTDC中搭建了直流融冰模型,仿真结果验证了所提控制策略的有效性。
[Abstract]:The existing DC ice-melting device uses thyristor controlled rectifier technology, which will consume certain reactive power and produce characteristic subharmonics in operation, which will have a certain impact on AC system. The full bridge modularized multilevel converter (MMC) has the ability of bi-directional operation of DC voltage and DC current, which can meet the requirements of DC melting ice for the operation of the converter. In this paper, the control strategy of DC ice melting device suitable for full bridge MMC is proposed. Firstly, the operation principle of the main circuit topology of the full-bridge MMC DC ice-melting device is introduced, and the modulation ratio definition suitable for the full-bridge MMC is given. Secondly, taking full advantage of the characteristics that the full bridge sub-module can output positive, zero and negative module voltage, the paper analyzes how to realize the zero-start boost / rise current to meet the ice melting requirements of different types and length lines, so that the DC voltage is very low. The AC side still maintains high power quality. Then, the reactive power compensation is studied based on reactive power compensation capacity, equipment utilization ratio and device margin, and the topology of reactive power compensation mode is determined. Finally, a DC ice-melting model is built in PSCAD/EMTDC, and the simulation results verify the effectiveness of the proposed control strategy.
【作者单位】：新能源电力系统国家重点实验室(华北电力大学);南方电网科学研究院;
【基金】：中国南方电网有限责任公司科技项目(KY2014-2-009)~~
【分类号】：TM752

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