A New Asymmetrical Multilevel Inverter Topology with reduced devices and low THD

In Pakistan, the generated power is not fulfilling the power in demand due to huge power shortfall. And especially in rural areas, the load shedding rate is high as compared to urban areas because these areas are far away from the power station and that is why they cause long-distance power line tra

Project Title

A New Asymmetrical Multilevel Inverter Topology with reduced devices and low THD

Project Area of Specialization

Shared Economy

Project Summary

In Pakistan, the generated power is not fulfilling the power in demand due to huge power shortfall. And especially in rural areas, the load shedding rate is high as compared to urban areas because these areas are far away from the power station and that is why they cause long-distance power line transmission losses. Renewable energy is the optimal solution for rural areas and reducing power shortfall because Pakistan is rich with solar irradiance and wind potential. Renewable energy is eco-friendly -doesn’t cause green housing effect-, where these resources can help in power generation so that the power shortfall of Pakistan can be reduced.

Renewable energy harvests energy Mostly in DC power from wherein domestic and industrial application AC power is supported. To bridge this gap a power conversion is required. Inverters are used to convert DC power into AC power, where the typical 2 level inverter converts the DC power into a square wave (square wave possesses all possible harmonics). That is why Multilevel Inverters (MLI) are favorable, due to their multiple levels in output they start resembling with the pure sine wave and hence less total harmonic distortion (THD). From this, it is concluded that the higher the number of levels of the multilevel inverter (MLI) output the lower the output THD will be. From the literature review, it has been concluded that classical topologies like Flying capacitor MLI, Neural point clamped MLI and cascaded H-bridge MLI increases the number of power electronic devices as the number of output levels increase, that is why now modified topologies are being used. There are two types of voltage source MLIs, symmetrical MLIs, and asymmetrical MLIs. The asymmetrical MLIs include voltage sources with different potentials and give a higher number of levels with fewer devices but the controlling of the switches is very difficult. From the literature review, it has been concluded that there is a need to design new topology with a smaller number of switching devices and low total harmonic distortion as per IEEE-519(2014). In this project a 27-level asymmetrical MLI has been proposed which is expected to generate a 27-level output with a smaller number of power semiconductor switches. MOSFETs will be used as power semiconductor switching devices that will be connected with a mircontrolling unit through driving circuits to switch MOSFETs to generated different voltage levels at the output. Combining the selected switching scheme different levels will be generated that will eventually correspond to a 27-level voltage output. The output is expected to have a final THD of 4.41% with reduced 14 switches in combination with a more simplified control scheme. The topology will not only satisfy the IEEE-519(2014) but will also provide an edge in terms of efficiency in comparison with the state-of-the-art counterparts.

Project Objectives

The main project objective is to propose/design a 27-level asymmetrical multilevel inverter topology. The topology will generate 27-level output which will highly affect the Total Harmonic Distortion (THD).

The other main goal of this proposed topology was to reduce Power electronic devices while generating more levels in output waveform for more resemblance with pure sinusoid waveform hence low harmonics in output waveform and less total harmonic distortion.

For topology validation, that either it works, or can it generate 27-level output waveform Software simulation should be done. After successful simulation prototyping of the topology should be carried out. For prototyping different power electronic devices can be substituted to check the best suitable power electronic device.

Project Implementation Method

Before practical implementation, the simulation of the topology will be done for validation of topology. MATLAB/Simulink has been used for simulation in which power and Simulink library has been used and switching pattern will be designed. After having the best results for the simulation, the practical implementation will be carried out. In which firstly different basic topologies of the inverter will be prototyped for the output analysis and the power electronic device behavior. The topology will be implemented on the electronic simulator (spice software’s) for behavior checking and biasing/ turning ON and OFF the power electronic devices. A driving circuit will be designed for power electronic devices for insolation purpose. Then the proposed 27-level asymmetrical multilevel inverter will be prototyped and using digital storage oscilloscope the waveform will be analyzed and the Total harmonic distortion and power losses of the power semiconductor devices will be calculated.

Benefits of the Project

The main motivation of this project was to utilize renewable energy sources for power generation instead of the typical conventional methods such as hydro, nuclear, fossil fuels, etc. which are causing green housing effect and not environmentally friendly. Conventional methods are reducing the fossil fuels storage which needs billions of years for regeneration.

The power station which generates power through a conventional method is far away from the consumers, which leads to long transmission lining for power supply and eventually causes high power transmission losses. Whereas small grids can be installed in different rural and urban areas where solar irradiance and wind potential is good and generate their own power for their respective areas.

The renewable energy is harvested in DC form that is why an Inverter is required for conversion of DC power into AC power so that the power harvested can be used in domestic applications. The classical inverters have many devices as the level of output increases which makes them quite expensive and causes power losses because each device has its own power dissipation. That is why a modified inverted topology should be designed which should be able to generate a high number of levels in output waveform and uses a smaller number of devices. This results in low total harmonic distortion because the output will be more similar to a pure sine wave and eventually less power distortion because a smaller number of devices are required for the level generator in modified topologies.

The university will have a prototype of a modified asymmetrical multilevel inverter topology for display and practice in power electronics and power system lab so that students can practice and analyze the inverter topologies. In this way, the students will be attracted towards the power conversion topologies.

Technical Details of Final Deliverable

1. A low-cost efficient inverter will be produced.
2. This inverter attaches with any renewable power source can also be used as a backup power system for any institute in case of any power shortfall.
3. The project will motivate the students toward power electronics and can be an example of modified inverter topologies for their better understanding with modified inverter topologies.
4. Can use in Power electronic laboratory or power system lab for a practical demonstration of Power converters (Inverters)
5. After a few modifications, it can attach with the PV arrays or renewable energy sources for power generation.
6. It can also use in domestic application like in homes with PV arrays as micro Grids and can also supply power to Grid in microscale.

Final Deliverable of the Project

HW/SW integrated system

Type of Industry

Energy , Others

Technologies

Shared Economy, Others

Sustainable Development Goals

Quality Education, Affordable and Clean Energy, Industry, Innovation and Infrastructure

Required Resources

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