Power Electronic Transformer

With the global trend to produce clean electrical energy, the penetration of renewable energy sources in existing electricity infrastructure is expected to increase signi?cantly within the next few years. The power electronic transformer (PET) is expected to play an essential role in future sma

Project Title

Power Electronic Transformer

Project Area of Specialization

Electrical/Electronic Engineering

Project Summary

With the global trend to produce clean electrical energy, the penetration of renewable energy sources in existing electricity infrastructure is expected to increase signi?cantly within the next few years. The power electronic transformer (PET) is expected to play an essential role in future smart grid topologies. Unlike traditional magnetic transformer, PET is ?exible enough to be of modular construction, enabling bi-directional power ?ow and can be employed for AC and DC grids. Moreover, PETs can control the voltage level and modulate both active and reactive power at the point of common coupling without the need to external ?exible AC transmission system device as per the current practice in conventional electricity grids. The rapid advancement in power semiconductors switching speed and power handling capacity will soon allow for the commercialization of grid-rated PETs. 

The presence of PET in a power system can improve the power quality of the grid. The PET allows uncoupling the side of the network from the side of the load; then if a disturbance occurs from one side, it does not affect the components connected in the other side of the PET. In addition, the PET allows to enhance the power factor, support overloads, and keep nominal voltage on the load side, even though the input voltage is affected by either a sag or a swell. Another advantage of the PET is their DC link, which allows the integration of distributed generation and energy storage. The power coming from the DC link can deliver power to the network, if required.

Project Objectives

• To analyze the functions of Traditional transformers in use of power system.
• Develop a single-phase Power Electronic Transformer (PET) design that considers the requirements of optimal power transfer.
• Evaluate different Power Electronic Transformer topologies suitable for distribution system.
• Elaborate the design tradeoffs between cost, efficiency, and volume which involve a proper core material selection and operating conditions.
• Investigate high voltage isolation consideration for the implementation of Power electronic transformer (PET) in distribution system.

Project Implementation Method

The design methodology is applicable to transformer no sinusoidal excitations that are typically encountered in power electronics, and considers the flux density optimization criteria presented in to maximize the transformer’s efficiency. The number of turns of the windings and the isolation distance between windings are used as free parameters to adjust the transformer leakage inductance required for maximum power transfer. The project will be completed using step by step from conception, simulating and prototyping methodology. The main components / blocks shall be prepared and manufactured one by one and initially tested as stand-alone and then integrated as a whole system.

Benefits of the Project

• The small size of PETs are friendly to environment.

• Volume and weight reductions which are critical in     applications characterized by space limitations.

• Soft-switching operation to achieve higher efficiency.

•I nstantaneous voltage regulation.

• Voltage sag compensation.

• Power factor correction.

Technical Details of Final Deliverable

It will convert 230 V A/C into DC voltages using bridge rectifier & shunt capacitors for filtering.

Then this DC output will be inverted into AC with high frequency around 50 KHz using PWM techniques  Now the voltage level will be stepped down by 2:1 turn ratio i.e 230/110 volts using high frequency transformer. 

Then this high frequency AC will be converted in DC 
At last stage DC will be inverted to AC with 50 Hz frequency. 

This is our output 110 volts AC. It can take load of 500 Watts.

PET topologies can be broadly classified in the four categories (a) single-stage topology with no DC link, (b) two-stage topology with HV DC link, (c) two-stage topology with LV DC link, and (d) three-stage topology with HV and LV DC link.

The topologies under (a) consist of a direct isolated AC-AC stage which might have the lowest cost and simplest approach among the other configurations. In addition, bi-directionality could be possible with four-quadrant switching devices. However, no DC links are available, thus reactive power compensation is not possible. In (b), an AC-DC conversion stage which provides a HV DC link is combined with a second stage DC-AC stage with galvanic isolation. Disturbance cancellation and reactive power compensation functionalities are possible with this configuration. Nonetheless, the lack of a LV DC link in (a) and (b) makes them unsuitable for applications in distribution systems where easy integration of renewable energies, and energy storage elements are desired.

Topologies under categories I and (d) overcome the limitation of an unavailable LV DC link. In I, an isolated AC-DC stage is followed by a DC-AC stage, thus a LV DC link is available. Category (d) includes topologies with a three-stage configuration combining an AC-DC stage followed by an isolated DC-DC stage and a DC-AC stage providing HV and LV DC link. Therefore, it can be concluded that, based on this classification, topologies under I and (d) are the best candidates for the PET implementation in distribution systems since they can provide all the required features expected from PET. In particular, (d) provides more controllability and flexibility since topologies for each of the three stages can be chosen from a variety of options. The main disadvantage is the large number of components which may lead to higher cost, and lower efficiency and power density.

Final Deliverable of the Project

Hardware System

Core Industry

Energy

Other Industries

Core Technology

Clean Tech

Other Technologies

Sustainable Development Goals

Industry, Innovation and Infrastructure, Sustainable Cities and Communities

Required Resources

If you need this project, please contact me on contact@adikhanofficial.com