PERFORMANCE AND COMPARISON ANALYSIS OF DIFFERENT VS CELL STRUCTIRES IN A MODULAR MULTILEVEL CONVERTERA

Project Title

PERFORMANCE AND COMPARISON ANALYSIS OF DIFFERENT VS CELL STRUCTIRES IN A MODULAR MULTILEVEL CONVERTERA

Project Area of Specialization Electrical/Electronic EngineeringProject Summary

SOLUTION - MODULAR MULTILEVEL CONVERTER: 

Many low voltage cells (one to n) are connected in series to produce a high voltage with excellent harmonic performance. ? A relatively low device switching frequency is achieved. ? The modularity and the scalability of the modular converters allow it to be competitive in high-voltage applications. ? The improved high-voltage insulation coordination requirements, simpler mechanical design, and service are other benefits of the MMCs compared to monolithic converters.

? Insulated Gate Bipolar Transistor is a three-terminal (emitter, collector, gate) semiconductor switching device used in different electronic devices, mostly for switching/processing complex wave patters with pulse width modulation (PWM). ? The building-block cell is the basic unit of any MMC configuration which can basically be either a dc/dc or a dc/ac power converter. ? Two types of cells: half bridge and full bridge. ? In half bridge: 2 IGBTs (switch S1 and S2) complementary to each other else they will short the DC bus, formed of a capacitor.

In full bridge: 4 IGBTs (switches S1 to S4) and a capacitor.

Project Objectives

AC transmission= voltage and current waves change direction every millisecond due to which losses occur. ? This does not happen in DC, in HVDC increased efficiency of transmission lines due to which power is rapidly transferred. ? HVDC substation= rectifiers (change AC to DC) and inverters (convert DC to AC) are placed at both ends of a line. ? Historically HVDC transmission was performed using thyristor-controlled Line Commutated Converter (LCC). To overcome it’s limitations, later Voltage Source Converters made with insulated gate bipolar transistors (IGBT) were used: ? it uses semiconductors that can be switched on and off autonomously, the converter can supply reactive power, it can operate with a delay and advance power factor and it can be used in isolated systems.

Project Implementation Method

VS Cell Structures of different levels (two level to multilevel) are compared. ? Half-bridge and full-bridge configurations are created using components of different values, ratings and features and used to test different possibilities to find the optimum power electronic building block. ? The project consists of 2 parts: a.) Software based Simulation of different half-bridge and full-bridge VS Cell Structures on SIMULINK. b.) Implementing circuits of 2 best results on hardware PCB, matching the simulation.

Benefits of the Project

The new HVDC technology based on the Voltage Source Converter (VSC) is a feasible and attractive solution that can fulfil almost all above challenges due to its distinct advantages in the areas of controllability and flexibility, e.g. independent control of active and reactive power, fast control response speed, etc. Therefore, much effort is devoted to further extend its advantages and eliminate its drawbacks, such as high losses compared to Current Source Converter (CSC) HVDC and ac system. 

A modular multilevel converter (MMC) is an advanced voltage source converter applicable to a wide range of medium and high-voltage applications. It has competitive advantages such as quality output performance, high modularity, simple scalability, and low voltage and current rating demand for the power switches.

Technical Details of Final Deliverable

The final deliverable of the project will be a collection of hardware and software sets. The circuit implementation for different VS Cell Structures will be initially done on Software, and then modelled on hardware to exhibit the results found through simulation.

The project will be finalized by writing a research paper, enclosing my results and observations, with the help of my supervisor.

Final Deliverable of the Project HW/SW integrated systemCore Industry Energy Other IndustriesCore Technology OthersOther TechnologiesSustainable Development Goals Industry, Innovation and Infrastructure, Responsible Consumption and ProductionRequired Resources

Item Name	Type	No. of Units	Per Unit Cost (in Rs)	Total (in Rs)
			Total in (Rs)	53600
IGBT TRANSISTORS	Equipment	20	400	8000
Dual Full-Bridge MOSFET Driver IC A4989SLDTR-T (38-TSSOP)	Equipment	6	400	2400
Fluke 101 Digital Multimeter	Equipment	1	9000	9000
UNI-T UTD2025CL DIGITAL STORAGE OSCILLOSCOPE	Equipment	1	30000	30000
INDUCTORS, CAPACITORS, RESISTORS	Equipment	50	50	2500
1N4148 DIODE	Equipment	10	10	100
IRF830	Equipment	10	50	500
IR2101 AND IR2112	Equipment	10	110	1100