基于电力电子变压器的能量路由器拓扑与控制策略研究

发布时间：2019-05-21 18:09

【摘要】：分布式能源运行受限于自然条件,发电具有间歇性,大量分布式能源的接入会使网络上产生双向功率流。传统的单一集中式发电正逐渐向集中式、分布式并存的发电方式转变,电能的单向流动正变为多向流动方式。传统的电力系统的配电运行方式很难胜任这样复杂的要求。以应用于交直流混合微网、作为公共连接点为目标设计电力电子变压器,研究其拓扑、控制和运行特性,充分发挥电力电子变压器的电气隔离、功率主动控制的功能,达到提供多电压等级的交直流接口和减小电网谐波等目的,有助于新能源事业的发展,对交直流混合微网乃至能源互联网的发展有着重要的意义。为确定以应用于交直流混合微网、实现能量路由器为目标设计的电力电子变压器的拓扑结构,依据现有对能源互联网、能量路由器、电力电子变压器的研究,选定了多模块级联拓扑结构,采用更为灵活的基于移相控制的双有源桥,进而确定输入级采用级联H桥结构,中间级采用独立的IBDC。确定拓扑结构后,在输入级采用混合调制策略,该调制方式综合了PWM和最近电平逼近的优点,降低了系统对各级联单元对同步的要求,同时有利于实现功率的均衡控制。中间级采用移相控制方式,可通过控制原副边电压电流达到能量双向控制的目的。同时,针对中间级DC-DC运行过程中出现的电压反转现象进行详尽的模态分析,提出了移相比、励磁电感和死区时间之间应满足的配合关系,并通过仿真和实验对理论进行了验证。在理论研究基础上,研制了一台单相380V/300V级联多电平电力电子变压器样机,给出了实验平台和控制电路的设计思路,并分别针对PET各个部分进行了可靠性验证,同时对所选用的参数设计方法和提出的控制方式进行了实验验证。最后针对样机,进行了抗扰动试验,结果表明,本文所设计的基于电力电子变压器的能量路由器可以满足电压隔离、能量主动双向调控和控制谐波的目标,能长时间稳定可靠运行,且能抵御网侧电压波动干扰。
[Abstract]:Distributed energy operation is limited to natural conditions, power generation is intermittent, a large number of distributed energy access will make the network produce two-way power flow. The traditional single centralized power generation is gradually changing to centralized, distributed and co-existing generation mode, and the one-way flow of electric energy is becoming multi-directional flow mode. The traditional distribution operation mode of power system is difficult to meet such complex requirements. The power electronic transformer is designed for AC / DC hybrid microgrid as the common connection point, and its topology, control and operation characteristics are studied, so as to give full play to the functions of electrical isolation and active power control of power electronic transformer. To provide multi-voltage level AC / DC interface and reduce power grid harmonics is helpful to the development of new energy industry and is of great significance to the development of AC / DC hybrid microgrid and even energy Internet. In order to determine the topology of power electronic transformer designed for AC / DC hybrid microgrid and realize energy router, according to the existing research on energy Internet, energy router and power electronic transformer, The multi-module cascade topology structure is selected, and a more flexible double active bridge based on phase shift control is adopted, and then the input cascade H bridge structure is determined, and the independent IBDC. is used in the middle stage. After the topology is determined, the hybrid modulation strategy is adopted in the input stage, which combines the advantages of PWM and the nearest level approximation, reduces the synchronization requirements of the connected units at all levels, and is beneficial to the realization of power equilibrium control. The middle stage adopts phase shift control mode, which can control the voltage and current of the original secondary side to achieve the purpose of energy bidirectional control. At the same time, the modal analysis of voltage reversal phenomenon in the operation of intermediate stage DC-DC is carried out in detail, and the matching relationship between excitation inductance and dead time is put forward. The theory is verified by simulation and experiment. On the basis of theoretical research, a prototype of single-phase 380V/300V cascade multi-level power electronic transformer is developed, the design idea of experimental platform and control circuit is given, and the reliability of each part of PET is verified respectively. At the same time, the selected parameter design method and the proposed control method are verified by experiments. Finally, the disturbance rejection test is carried out for the prototype. The results show that the energy router based on power electronic transformer can meet the objectives of voltage isolation, energy active bidirectional control and harmonic control. It can run stably and reliably for a long time, and can resist the interference of voltage fluctuation on the network side.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TK01;TM41

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