A New Power Electronic Transformer Applied to Distribution System

2013 ◽  
Vol 448-453 ◽  
pp. 2879-2885
Author(s):  
Xing Wu Yang ◽  
Xin Hua Xiong ◽  
Wu Ouyang ◽  
Shuai Yuan
Keyword(s):  
Distribution System ◽  
Control Method ◽  
Low Voltage ◽  
Power Electronic ◽  
Electronic Transformer ◽  
Power Electronic Transformer ◽  
Third Stage ◽  
Harmonic Components ◽  
Pet System ◽  
Voltage Conversion

This paper proposes a new power electronic transformer (PET) to be used for distribution system, which is composed of the three-stage power circuits. The input stage uses Modular Multilevel Converter (MMC) to reduce the voltage stress rating of components, meanwhile, the harmonic components in the current will be deduced significantly, to make DC capacitor voltage of MMC rectifier balance, a control method is proposed. The isolation stage use a middle-frequency transformer to realize voltage conversion and isolation of the low-voltage side from the high-voltage side. In the third-stage, a inverter outputs the desired voltage and power to the load. The simulation results are presented to show the validity of the proposed PET system.

scholarly journals Virtual Submodule Predictive Control method for Power Electronic Transformer based on MMC Structure

2019 ◽  
Vol 136 ◽  
pp. 01024
Author(s):  
Jinghong Zhao ◽  
Xing Huang ◽  
Honghao Zhao ◽  
Xin Hong
Keyword(s):  
Predictive Control ◽  
Power Distribution ◽  
Control Method ◽  
Power Electronic ◽  
Switching Loss ◽  
Multilevel Converter ◽  
Efficient Operation ◽  
High Loss ◽  
Electronic Transformer ◽  
Power Electronic Transformer

In order to achieve flexible and efficient operation of intelligent power distribution, solving the problems of traditional distribution transformer such as large volume and weight, easy to generate harmonics when overload, and need supporting protection equipment to protect it when failure, etc. We propose a power electronic transformer structure based on modular multilevel converter (MMC). Firstly, we consider the multi-dimensional control target of MMC converter to establish a mathematical model. Then a virtual submodule predictive control method is proposed. The method introduces the concept of virtual submodule to realize the optimal switching state rapid mapping and reduce the switching loss of MMC. Finally, the experimental results show that the mmc-based power electronic transformer has excellent dynamic steady-state performance and can effectively overcome the high loss of traditional predictive control.

scholarly journals Optimal Scheduling Strategy of AC/DC Hybrid Distribution Network Based on Power Electronic Transformer

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3219
Author(s):  
Qingwen Peng ◽  
Lu Qu ◽  
Zhichang Yuan ◽  
Xiaorui Wang ◽  
Yukun Chen ◽  
...  
Keyword(s):  
Control Structure ◽  
Low Voltage ◽  
Distribution Network ◽  
Optimal Scheduling ◽  
Power Electronic ◽  
Scheduling Strategy ◽  
Electronic Transformer ◽  
Power Electronic Transformer ◽  
Dc Bus ◽  
Hybrid Distribution

The AC/DC hybrid distribution network is composed of a medium-voltage DC bus, a low-voltage DC bus, and a power electronic transformer, and has the characteristics of multi-voltage level, multi-DC bus, and multi-converter, so its operation mode and optimal scheduling strategy are more complex. Firstly, this paper constructs the AC/DC hybrid distribution network using an power electronic transformer. Then, a two-layer control structure including a scheduling management layer and a bus control layer is proposed, which simplifies the control structure and gives full play to the role of “energy routing” function of the power electronic transformer. Moreover, the minimum operation cost of the AC/DC hybrid distribution network in the whole scheduling cycle is taken as the optimization objective, considering the characteristics of various distributed generations, the structure of AC/DC hybrid distribution network, and the interaction of “source–load–storage”. Finally, the optimal scheduling model of the AC/DC hybrid distribution network based on power electronic transformer is established, and the feasibility of the optimal scheduling strategy is verified by the open-source solver, which can realize the complete absorption of renewable energy and the optimal coordinated control of “source–load–storage”.

scholarly journals DAB Based DC-DC High Frequency Link PET for Interconnecting MVDC-LVDC Grids

2021 ◽  
Vol 7 (05) ◽  
pp. 165-171
Author(s):  
D.Srinivasa Rao & Dr. Anupama A. Deshpande
Keyword(s):  
High Frequency ◽  
Low Voltage ◽  
Short Circuit ◽  
Power Electronic ◽  
Distribution Grid ◽  
Medium Voltage ◽  
Electronic Transformer ◽  
Power Electronic Transformer ◽  
Wide Range ◽  
Medium Voltage Dc

This paper proposes dual active bridge (DAB) based high frequency power electronic transformer (PET) for interconnecting medium voltage dc (MVDC) and low voltage dc (LVDC) grids for dc power distribution. The above proposed concept works on dual active phase shift principle and square wave HF modulation technique for bidirectional power transfer. Compared to the traditional dc transformer scheme, The proposed power electronic transformer (PET) can disconnect from LVDC distribution grid effectively as a dc breaker when a short circuit fault occurs in the distribution grid. The isolated DC-DC PET topology with a wide range of voltage conversion ratio is useful for High Voltage DC tapping. The DAB based on switched capacitor is connected to the medium voltage DC side and acts as an inverter. The proposed topology has the ability to transfer higher power, and lower circulating power, lower high frequency link voltage, and RMS current and peak values with the same transmission power in the MVDC side. This paper analyzes the topology, voltage and power characterization, control strategy in detail. Increase in the intermediate AC frequency will reduce the size of the transformer and other passive elements significantly in the circuit. The theoretical analysis is supported by MATLAB simulation.

scholarly journals A novel low voltage ride through strategy for cascaded power electronic transformer

2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Jiexiang Han ◽  
Xiangping Kong ◽  
Peng Li ◽  
Zhe Zhang ◽  
Xianggen Yin
Keyword(s):  
Low Voltage ◽  
System Stability ◽  
Positive Sequence ◽  
Voltage Sag ◽  
Power Electronic ◽  
Operating Characteristics ◽  
Electronic Transformer ◽  
Low Voltage Ride Through ◽  
Power Electronic Transformer ◽  
Voltage Recovery

Abstract In view of the operating characteristics for voltage sags of AC side of the power electronic transformer(PET), a low-voltage ride through(LVRT) strategy adapted to bidirectional power exchange of PET is proposed for the purposes of maintaining the system stability, assisting the system voltage recovery and protecting PET safety. During the asymmetric voltage sag, the negative sequence current of PET is eliminated to ensure the symmetry of the injected current. According to the degree of positive sequence voltage sag, the reactive current injection is provided to assist in voltage recovery. According to the PET active power condition before the voltage sag, the level and direction of which are maintained as far as possible without exceeding the limit, for which the disturbance to the AC and DC grids is reduced. Finally, the effectiveness of the proposed LVRT strategy is verified by simulation model.

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