一种适用于新能源并网的高增益单向直流变压器

摘要

提出一种名为高电压比级联式LC-AC transformer(LCT)型单向直流-直流变压器,特别适用于新能源并网等应用场合.该变压器首先通过电压源型换流器(VSC)将直流电压逆变成交流电压,利用电感电容(LC)电路取得第一级升压.然后,LC电路输出的电压将会通过交流变压器得到进一步升高,从而通过两级升压实现40倍左右高电压比.最后,利用二极管电路将交流电压整流得到直流电压.本文首先阐述了LCT DC-DC的参数设计步骤,同时提出了一种有效的有功功率控制策略,研究拓扑的器件选择及其运行损耗估算.最后通过在PSCAD/EMTDC下搭建的LCT DC-DC仿真算例证明本文所提出拓扑的技术可行性.%This paper proposes a cascaded LC-AC transformer unidirectional DC-DC converter (LCT DC-DC), which has high stepping ratio and is suitable for integrating renewable energy sources to DC grid. The presented LCT DC-DC converter can achieve about 40 times stepping ratio through the two-stage step-up of voltage. To begin with, the voltage source converters (VSC) are used to invert DC to AC, an adequately designed inductor-capacitor circuit is then employed to achieve voltage step up in the first stage. In the second stage, an AC transformer will further boost the output voltage. Diode rectifiers are finally used to rectify AC to DC. This paper firstly introduces the design procedures of the LCT DC-DC. The corresponding active power control strategy and the power loss estimations are studied as well. The simulations on PSCAD/EMTDC confirm the technical feasibility of the proposed topology.