T型三电平逆变器技术研究
发布时间：2018-11-03 18:52
【摘要】：随着能源危机和环境污染问题日益严重，，包括光伏发电在内的新能源利用越来越受到人们重视。在可再生能源开发中，交直流混合微电网技术是重要发展方向；其中，双向AC/DC变换器作为交流母线和直流母线的传输媒介，其拓扑和控制技术亟待研究。在双向AC/DC变换器拓扑的选取上，T型三电平拓扑改进了传统NPC三电平拓扑器件过多、损耗分布不均等缺点。因此，本文基于T型三电平拓扑展开研究。 本文首先分析了单相T型三电平逆变器的工作原理和调制控制策略，搭建了损耗模型并研究了电路中各个器件的损耗分布，搭建了4kW的实验样机平台，给出了并网实验结果，包括并网稳态和动态波形、效率等。分析了三相T型三电平逆变器的工作原理，推导了其数学模型。通过去除产生大共模电压的开关矢量，得到一种低共模电压的SVPWM调制算法。在该算法基础上，采用了两种不同的小扇区划分方式，对比了逆变器运行时的共模电压和漏电流，得出了更有利于抑制漏电流的一种划分方式。推导了两台并联变换器的共模电压等效模型，指出了共模电压的脉动幅值和频率是影响漏电流大小的重要因素。采用载波移相180度的调制算法，可以抵消共模电压频谱中的开关频率次分量，使得漏电流得到有效抑制。同时，为了满足不同的工况需要，研究了并联逆变器系统的能量双向流动管理，分别采用逆变电压环和整流电压环判断控制，保证了功率流的一致性，并加入直流侧下垂控制实现了并联逆变器的均流。 最后，搭建了两台T型三相三电平逆变器并联实验样机，设计了系统的功率电路、驱动保护电路等，进行了三相逆变器并网的动态和稳态实验。对比了在分别采用两种不同小扇区划分方式条件下，逆变器并网运行时的共模电压和漏电流。进行了两台变换器并联的稳态实验，给出了整流运行和逆变运行状态下的波形。实验结果验证了理论分析及仿真结果的正确性。
[Abstract]:With the increasing energy crisis and environmental pollution, people pay more and more attention to the use of new energy, including photovoltaic power generation. In the development of renewable energy, AC / DC hybrid microgrid technology is an important development direction, and the topology and control technology of bi-directional AC/DC converter, as the transmission medium of AC bus and DC bus, need to be studied urgently. In the selection of bi-directional AC/DC converter topology, T-type three-level topology improves the traditional NPC three-level topology with too many devices and uneven loss distribution. Therefore, this thesis is based on T-type three-level topology. In this paper, the working principle and modulation control strategy of single-phase T type three-level inverter are analyzed, the loss model is built and the loss distribution of each device in the circuit is studied, the experimental prototype platform of 4kW is built, and the experimental results of grid-connected experiment are given. Including grid-connected steady and dynamic waveforms, efficiency and so on. The working principle of three-phase T-type three-level inverter is analyzed and its mathematical model is deduced. A low common-mode voltage (SVPWM) modulation algorithm is proposed by removing switching vectors that generate large common-mode voltages. On the basis of this algorithm, two different small sector partitioning methods are adopted, and the common-mode voltage and leakage current are compared when the inverter is running, and a partition method is obtained which is more favorable to the suppression of leakage current. The equivalent common-mode voltage model of two parallel converters is derived. It is pointed out that the pulse amplitude and frequency of common-mode voltage are the important factors affecting the leakage current. The switching frequency subcomponent in the common-mode voltage spectrum can be cancelled by using the modulation algorithm of the carrier phase shift 180 degree, which can effectively suppress the leakage current. At the same time, in order to meet the needs of different operating conditions, the energy bidirectional flow management of parallel inverter system is studied. The inverter voltage loop and rectifier voltage loop judgement control are used to ensure the consistency of power flow. DC side droop control is added to realize the current sharing of parallel inverter. Finally, two parallel experimental prototypes of T type three-phase three-level inverter are built, and the power circuit and drive protection circuit of the system are designed, and the dynamic and steady state experiments of the three-phase inverter connected to the grid are carried out. The common-mode voltage and leakage current of the inverter in grid-connected operation are compared under the condition that two different small sectors are used. The steady state experiments of two parallel converters are carried out, and the waveforms of rectifier operation and inverter operation are given. The experimental results verify the correctness of the theoretical analysis and simulation results.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM464
[Abstract]:With the increasing energy crisis and environmental pollution, people pay more and more attention to the use of new energy, including photovoltaic power generation. In the development of renewable energy, AC / DC hybrid microgrid technology is an important development direction, and the topology and control technology of bi-directional AC/DC converter, as the transmission medium of AC bus and DC bus, need to be studied urgently. In the selection of bi-directional AC/DC converter topology, T-type three-level topology improves the traditional NPC three-level topology with too many devices and uneven loss distribution. Therefore, this thesis is based on T-type three-level topology. In this paper, the working principle and modulation control strategy of single-phase T type three-level inverter are analyzed, the loss model is built and the loss distribution of each device in the circuit is studied, the experimental prototype platform of 4kW is built, and the experimental results of grid-connected experiment are given. Including grid-connected steady and dynamic waveforms, efficiency and so on. The working principle of three-phase T-type three-level inverter is analyzed and its mathematical model is deduced. A low common-mode voltage (SVPWM) modulation algorithm is proposed by removing switching vectors that generate large common-mode voltages. On the basis of this algorithm, two different small sector partitioning methods are adopted, and the common-mode voltage and leakage current are compared when the inverter is running, and a partition method is obtained which is more favorable to the suppression of leakage current. The equivalent common-mode voltage model of two parallel converters is derived. It is pointed out that the pulse amplitude and frequency of common-mode voltage are the important factors affecting the leakage current. The switching frequency subcomponent in the common-mode voltage spectrum can be cancelled by using the modulation algorithm of the carrier phase shift 180 degree, which can effectively suppress the leakage current. At the same time, in order to meet the needs of different operating conditions, the energy bidirectional flow management of parallel inverter system is studied. The inverter voltage loop and rectifier voltage loop judgement control are used to ensure the consistency of power flow. DC side droop control is added to realize the current sharing of parallel inverter. Finally, two parallel experimental prototypes of T type three-phase three-level inverter are built, and the power circuit and drive protection circuit of the system are designed, and the dynamic and steady state experiments of the three-phase inverter connected to the grid are carried out. The common-mode voltage and leakage current of the inverter in grid-connected operation are compared under the condition that two different small sectors are used. The steady state experiments of two parallel converters are carried out, and the waveforms of rectifier operation and inverter operation are given. The experimental results verify the correctness of the theoretical analysis and simulation results.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM464
【参考文献】
相关期刊论文 前10条
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2 马琳;孙凯;Remus Teodorescu;金新民;;高效率中点钳位型光伏逆变器拓扑比较[J];电工技术学报;2011年02期
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