适用于直流配电网的直流变压器技术研究
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摘要
采用基于模块化输入串联输出并联拓扑的直流变压器,实现了柔性中压直流配电网和低压直流微电网之间的电压等级变换和功率双向传输。直流变压器的子单元基于LC串联谐振原理,采用定频不移相控制策略。此外,为了抑制较大的启动冲击电流,提出了一种软启动控制策略:通过脉冲占空比切换的方式控制输入端全桥电路的占空比,从小占空比缓慢切换到额定占空比。设计并生产了一台500 kW,±10 kV/750 V直流变压器,实验结果验证了所提方案的正确性和可行性。
A DC transformer based on modular input-series output-parallel topology is used,which realizes voltage level conversion and power transmission between flexible medium voltage DC distribution network and low voltage DC microgrid.The sub-unit of the DC transformer is based on the LC series resonance principle and adopts a fixed-frequency phase-shifting control strategy.In addition, a soft-start control strategy is proposed to suppress a large start-up inrush current by controlling the duty cycle of the input full-bridge circuit to switch slowly from a small duty cycle to a rated duty cycle by switching the pulse duty cycle.A 500 kW,± 10 kV/750 V DC transformer is designed and produced.The experimental results verify the correctness and feasibility of the proposed scheme.
A DC transformer based on modular input-series output-parallel topology is used,which realizes voltage level conversion and power transmission between flexible medium voltage DC distribution network and low voltage DC microgrid.The sub-unit of the DC transformer is based on the LC series resonance principle and adopts a fixed-frequency phase-shifting control strategy.In addition, a soft-start control strategy is proposed to suppress a large start-up inrush current by controlling the duty cycle of the input full-bridge circuit to switch slowly from a small duty cycle to a rated duty cycle by switching the pulse duty cycle.A 500 kW,± 10 kV/750 V DC transformer is designed and produced.The experimental results verify the correctness and feasibility of the proposed scheme.
引文
[1]孙鹏飞,贺春光,邵华,等.直流配电网研究现状与发展[J].电力自动化设备,2016,36(6):64-73.
[2]赵彪,宋强,刘文华,等.用于柔性直流配电的高频链直流固态变压器[J].中国电机工程学报,2014,34(25):4285-4303.
[3]辛玉宝,辛玉才,张方华,等.基于全桥LLC谐振的双向直流变压器[J].电力电子技术,2013,47(4):3-5.
[4]陈启超,纪延超,王建赜.双向CLLLC谐振型直流变压器的分析与设计[J].中国电机工程学报,2014,34(18):2898-2905.
[2]赵彪,宋强,刘文华,等.用于柔性直流配电的高频链直流固态变压器[J].中国电机工程学报,2014,34(25):4285-4303.
[3]辛玉宝,辛玉才,张方华,等.基于全桥LLC谐振的双向直流变压器[J].电力电子技术,2013,47(4):3-5.
[4]陈启超,纪延超,王建赜.双向CLLLC谐振型直流变压器的分析与设计[J].中国电机工程学报,2014,34(18):2898-2905.