Design of multilevel inverter with multi RES and double level CHB MLI

Project Title

Design of multilevel inverter with multi RES and double level CHB MLI

Project Area of Specialization Electrical/Electronic EngineeringProject Summary

Power electronic converters are used to transform one form of energy to another. The inverter is one among those types; it converts direct electrical current into alternating electrical current at desired frequency. To improve the voltage profile and efficiency of the overall system, multilevel inverters (MLI) are introduced.

 In recent times, the market for MLI is becoming high in industrial sectors as well as in the fields where there is a need for high-power and high-voltage rating devices. Another interesting factor in the case of multilevel inverter is that it can be easily interfaced with renewable energy sources, plug in electric vehicles, batteries and capacitors .MLI are classified in different types but we will only focus on CHB MLI .

The hybrid renewable energy sources (HRES) have been progressively researched and invented to satisfy the increasing energy demand, and gained broad attention in recent years as of their prosperity of being pollutant nature. In multi RES two or more renewable resources are joined to make efficient power supply reliability.

We will use wind and solar RES to get the continuous electrical power because they both are efficient to use together . Wind  is easily available and collected by wind turbines with high power capacity. Solar power is another auspicious green energy source since it is most abundant and easily harnessed by using PV modules. Actually, wind and solar power complement each other since during  the night time and cloudy days when solar power is less available but strong winds are mostly to occur whereas weak winds usually occur in sunny days. Hence, irrespective of varying environmental conditions a hybrid wind-solar energy conversion system (HWSECS) can deliver continuous output power supply than  any other individual power generation systems.

The wind energy conversion system(WECS) and solar energy conversion system(SECS) are connected individually to an isolated dc-links of the CHB ML through their respective DC/DC converters based maximum power point tracking(MPPT) system. The CHB topology when endorsed as PWM rectifier sustain with the capacitor unbalancing issues among the dc links feeding distinct dc loads and the same arise when piloted in regenerative operation with distinct sources cracking  uneven power into each  cell.

By using this modification of multilevel inverter we can get continuous supply of electricity and the problem of load shedding may decrease . One of the most important advantage is that we will use renewable resources . Renewable resources is pollution free natural resources and we can get every day without any cause of environmental effect . And everyone can fix this system to their nearby house,office school and other commercial areas .

Project Objectives

The project objectives are :

To design multilevel inverter that will eliminate the shortcomings of conventional single level inverter .

To simulate multilevel inverter (MLI) topology with different modulations techniques and compare the output voltage characteristics.

 To propose one of the MLI topology as the best topology to be used in this project.

To design a multilevel inverter that will eliminate the shortage of electrical energy consumption by using renewable energy because renewable energy resources which is environmentally friendly and reduce the full dependency on the fossil fuel resources which is the main factor for global warming and environmental pollution.

Project Implementation Method

This project starts by collecting the required and relevant information on multilevel Inverter topologies and its modulation methods. From the literature review three different multilevel inverter topology proposed and one of t topology are chosen as the focus of the project for comparison purposes in terms of operation and characteristics. MATLAB/Simulink blocks are used to construct these MLI topologies and the modulation method. Simulation of both MLI allows generation of the respective output voltage waveforms which are used to obtain the required data for further analysis.

We will implement this project by following steps .

1. Literature review (understanding the project )
2. Implementation the circuit using MATLAB Simulink
3. Analysis of the results
4. Design the hardware project
5. Write report

The    WECS and SECS are connected individually to isolated dc-links of the proposed double level CHB MLI through their respective boost converters based MPPT .The dc voltages ‘Vwind’ and ‘VPV’ are acquired from PMSG rectified output voltage and PV array respectively. By applying the P&O MPPT algorithm to the power semiconductor switches, the boost converter can extract maximum power from the wind turbine and PV array individually.  The dc-link voltages(VDC1 andVDC2)will be kept balanced by  the use of SPWM  along  with  proposed  control scheme.

Benefits of the Project

This project is about multilevel inverter (MLI) .The multilevel inverter used to convert the DC energy to AC energy which will be connected to electricity grid. Due to these negatives impacts a rapid progress in finding an alternatives and renewable energy has attained a significant interests in the area of researches to eliminate the shortage of electricity .

In real world most of renewable energy resources that has been used is a DC energy in nature such as solar energy ,wind, tidal and biomass ,however the electrical transmission systems is in AC and not all of the loads (appliances/machines) are using the direct current (DC) power supply as their sources. Most of them need an A C power as their main source. This is where the inverter is needed to convert DC energy to AC energy. The concept of multilevel inverter is to produce multilevel output voltages with less power switching loss and less harmonic distortions.

Technical Details of Final Deliverable

The proposed  CHB MLI having  two HBC modules with independent solar and wind systems under inconsistent solar radiation and wind speed respectively  are connected to the two isolated dc-links. .As two  HBC modules  per phase are used in proposed CHB MLI, DOUBLE -levels are  obtained in  the converter output ac  side  phase voltage. Increase  in number of HBC modules, results  in more  levels  in converter output voltages, thus reducing the device stress in the HBC. This also expunge  the  requirement of filters  on ac side ,and number of RES can be increased . The maximum power recommended by the respective MPPTs of WECS and SECS is variable in reference to the available environmental conditions. Therefore, the extract able currents from the sources are distinct and  further the capacitor voltages in the isolated dc-links of the CHB MLI  are not equal. Dynamical properties of the  system are expressed  by using a  proposed mathematical analysis.

If isolated RES connected with respective dc-link of HBC in proposed system is assumed identical then the two capacitors of the respective cell equitably , share half of the VDC. Desired converter output phase  voltage can be  obtained by selecting proper  switching  function.

This is the simulation model but hardware implementation is required so we are currently working on it .

Final Deliverable of the Project HW/SW integrated systemCore Industry Energy Other Industries Education , Others Core Technology OthersOther TechnologiesSustainable Development Goals Good Health and Well-Being for People, Affordable and Clean Energy, Partnerships to achieve the GoalRequired Resources

Item Name	Type	No. of Units	Per Unit Cost (in Rs)	Total (in Rs)
			Total in (Rs)	67000
Maximum power point tracker (MPPT)	Equipment	2	10000	20000
PV panel	Equipment	1	5000	5000
wind turbine	Equipment	1	25000	25000
Multilevel inverter	Equipment	1	15000	15000
inductor ,capacitor	Equipment	1	2000	2000