Lec 1: Introduction

Summary

This course introduces the design of power electronic converters, essential for transforming power from one form to another efficiently. It covers a wide range of applications, from electric drives and renewable energy to electric vehicles and wireless power charging. The curriculum focuses on theoretical concepts, practical design techniques, and hands-on experience with simulation tools, component selection, thermal and magnetics design, and electromagnetic interference mitigation. Students will gain the skills to design and test power electronic converters for various applications.

Takeaways

• 🔌 Power electronics is the branch of electronics that deals with the conversion of power from one form to another, such as changing voltage or frequency levels.
• 📦 Power electronic converters can be visualized as a 'box' containing circuits that transform power, aiming for maximum efficiency and minimal energy loss during conversion.
• 🏗️ Applications of power electronics are vast, including electric drives like DC and AC motor drives, which utilize power electronic converters for speed and torque control.
• 🔋 Power electronics is crucial in Switched-Mode Power Supply (SMPS) applications, found in computers and various charging devices, where it facilitates DC-to-DC conversion.
• 🌞 Renewable energy systems, such as solar PV farms, rely heavily on power electronics for converting variable DC power from sunlight into a fixed voltage and frequency suitable for the grid.
• 🚗 The emerging field of electric vehicles, including cars and buses, is heavily dependent on power electronics for motor control and battery charging systems.
• 🔌 Power electronic converters are used in wireless power charging, employing air core transformers to transfer power between coils for devices like phones and cars.
• 🛠️ Power electronic converters consist of various components like power semiconductor devices, inductors, transformers, and heat sinks, each playing a role in the conversion process.
• 🔍 The course on Power Electronics Design aims to teach theoretical concepts and practical skills, including the analysis, simulation, and testing of power electronic converters.
• 🛠️ Students will learn to analyze power electronic converters from a design perspective, focusing on component ratings and specifications, and understanding power semiconductor devices and their data sheets.
• 🔧 Practical aspects of power electronics design, such as thermal and magnetics design, gate drivers, snubber design, and electromagnetic interference reduction, will be covered in the course.

Q & A

What is the primary function of power electronics?

The primary function of power electronics is to convert power from one form to another, such as changing voltage or frequency levels, while aiming to save the maximum amount of energy and maintain high efficiency.

How is a power electronic converter typically represented in diagrams?

A power electronic converter is typically represented as a box in diagrams, with the power electronic circuit inside it, showing the input and output sides which may have different voltage or frequency levels.

What are some common applications of power electronics?

Common applications of power electronics include electric drives, DC-to-DC conversion for SMPS applications, renewable energy applications like solar and wind power generation, electric vehicles, and wireless power charging.

What is the role of power electronics in electric drives?

In electric drives, power electronics is used for speed and torque control of motors, such as in DC motor drives where a DC-to-DC converter is employed.

How does power electronics contribute to renewable energy systems like solar PV farms?

Power electronics in solar PV farms is used to convert the variable DC power generated by the solar panels into a fixed voltage and frequency AC power that can be integrated into the grid.

What is a voltage source inverter and why is it used in AC motor drives?

A voltage source inverter is a type of power electronic converter that converts DC power into AC power. It is used in AC motor drives to provide variable voltage and frequency for speed and torque control of the motor.

What is the significance of power electronics in electric vehicles, such as electric cars?

In electric vehicles, power electronics is crucial for controlling the motor that drives the wheels and for charging the batteries, which often requires high currents and specific voltage levels.

What components are typically found inside a power electronic converter?

Inside a power electronic converter, one can typically find power semiconductor devices, inductors, transformers, small electronic ICs, heat sinks, and other components necessary for the conversion process.

Why is it important for power electronics engineers to understand theoretical concepts before designing power electronic converters?

Understanding theoretical concepts is important for power electronics engineers to ensure proper design, avoid novice mistakes, and achieve satisfactory performance in the power electronic converters they create.

What are some of the simulation tools and techniques that might be taught in a course on the design of power electronic converters?

Courses on the design of power electronic converters may teach the use of simulation tools for power electronics design, PCB designing, schematic designing, and provide demonstrations on how to experimentally test and verify power electronic converters.

What are the expected outcomes for students after completing a course on the design of power electronic converters?

After completing the course, students should be able to independently design power electronic converters, understand the theoretical concepts behind good design practices, and have knowledge on how to experimentally test and verify their designs.

Outlines

00:00

🔌 Introduction to Power Electronics and Converters

The first paragraph introduces the fundamental concept of Power Electronics as the field of electronics dedicated to the conversion of power from one form to another, such as changing voltage or frequency levels. It emphasizes the importance of efficiency in these conversions to minimize energy loss. The paragraph also provides an overview of the physical representation of a power electronic converter and outlines various applications, including electric drives like DC and AC motor drives, which utilize power electronic converters for speed and torque control. The narrative includes examples of different power electronic circuits used in these applications, such as rectifiers and voltage source inverters, and highlights the significance of power electronics in modern technology.

05:05

🔋 Applications of Power Electronics in Charging and Renewable Energy

This paragraph delves into the diverse applications of power electronics, focusing on DC-to-DC conversion in Switched-Mode Power Supplies (SMPS) used in computers and charging devices. It mentions the prevalence of power electronic converters in everyday life, from small chargers to high-power server applications. The paragraph also covers the role of power electronics in UPS systems, which perform DC-to-AC conversion, and the importance of designing converters suitable for various power levels. Additionally, it touches on the use of power electronics in renewable energy, particularly in solar PV farms, where converters are essential for managing variable DC output and converting it to a fixed grid voltage and frequency.

10:07

🚗 Power Electronics in Electric Vehicles and Wind Energy

The third paragraph discusses the critical role of power electronics in electric vehicles, including their use in motor control and battery charging. It highlights the need for high-current power electronic converters for fast charging applications. The paragraph also addresses the application of power electronics in wind energy, explaining how variable voltage and frequency outputs from wind turbines must be converted to a fixed grid standard. It provides an overview of the components found within power electronic converters, such as power semiconductor devices, inductors, transformers, and heat sinks, and underscores the importance of practical design knowledge for realizing these circuits effectively.

15:14

🛠️ Power Electronics Design Principles and Component Selection

This paragraph emphasizes the importance of understanding power electronics design principles for engineers. It discusses the variety of power electronic converters required for different applications, which can range from simple DC-to-DC to complex multi-stage conversions. The paragraph stresses that while there are common concepts applicable to all converter designs, each application may necessitate unique circuit configurations. It also touches on the components typically found inside a power electronic converter, such as inductors, capacitors, and heat sinks, and the need for engineers to know how to practically implement and design these converters based on theoretical knowledge.

20:19

📚 Course Overview on Power Electronics Converter Design

The final paragraph outlines the content and objectives of a course on the design of power electronic converters. It covers theoretical concepts, practical considerations, and the use of simulation tools for design. The course aims to teach students how to analyze and design power electronic converters from a practical perspective, including understanding power semiconductor devices, gate drivers, snubber designs, thermal and magnetics design, and addressing electromagnetic interference. The course concludes with demonstrations on experimental testing and verification of power electronic converters, equipping students with the ability to independently design and evaluate power electronic hardware.

Keywords

💡Power Electronics

Power Electronics is a branch of electronics that deals with the conversion of electrical power from one form to another. In the context of the video, it is the core theme, as it discusses the various ways power is converted and managed in different applications. The script mentions that power electronics is used to convert power to save maximum energy, which is crucial for efficient power management.

💡Power Electronic Converter

A Power Electronic Converter is a device that facilitates the conversion of power from one voltage or frequency level to another. The script describes it as a 'box' that contains power electronic circuits, which can take AC or DC as input and provide the required output form, whether it be a different voltage level or a different form of power, such as AC or DC.

💡Efficiency

Efficiency in the context of power electronics refers to the ratio of the useful power output to the total power input, with the goal of minimizing energy loss. The script emphasizes the importance of maximum efficiency during power conversion processes, which is a key objective in power electronic design.

💡Electric Drives

Electric Drives are systems that use electric motors to convert electrical energy into mechanical energy. The script mentions that one of the first applications of power electronics is in electric drives, specifically in DC motor drives, where a DC-to-DC converter is used for speed-torque control.

💡DC-to-DC Converter

A DC-to-DC Converter is a type of power electronic converter that changes the voltage level of DC power. The script explains that different types of power electronic circuits may be used in DC-to-DC converters, which are essential for applications like motor drives and power supply management systems.

💡AC Motor Drive

An AC Motor Drive is a system that controls the operation of an AC motor using power electronics. The script describes how AC motor drives can contain rectifiers and voltage source inverters to manage the variable voltage and frequency needed for speed-torque control of induction motors.

💡Voltage Source Inverter (VSI)

A Voltage Source Inverter is a power electronic device that converts DC power into AC power. The script uses the VSI as an example of how AC motor drives can produce variable voltage and frequency, which is essential for controlling the speed and torque of induction motors.

💡SMPS (Switched-Mode Power Supply)

SMPS refers to power supplies that switch their output stage at high frequency and use a small high-frequency transformer, making them efficient and compact. The script mentions SMPS as an application of power electronics in devices like computers and chargers, where different DC voltages are required.

💡Renewable Energy

Renewable Energy is energy derived from natural processes that are replenished at a higher rate than they are consumed. The script discusses how power electronics plays a vital role in renewable energy applications, such as solar and wind power, by converting variable DC power into a fixed voltage and frequency suitable for the grid.

💡Grid-Tied Inverter

A Grid-Tied Inverter is a power electronic device that converts DC power, such as that generated by solar panels, into AC power that can be fed into the electrical grid. The script uses the grid-tied inverter as an example of the multiple conversions that may be required in renewable energy systems.

💡Power Semiconductor Devices

Power Semiconductor Devices are components used in power electronics to control large amounts of electrical power. The script mentions these devices as integral parts of power electronic converters, highlighting their importance in the practical realization of power electronic circuits.

💡Design Perspective

The term 'Design Perspective' refers to the approach taken when planning and creating a power electronic converter, considering factors like component ratings, specifications, and overall system performance. The script emphasizes the importance of understanding design concepts to avoid novice designs and achieve satisfactory performance in power electronic applications.

Highlights

Power electronics is used for conversion of power from one form to another while maximizing energy efficiency.

Power electronic converters can take various forms, such as AC/DC or DC/DC, to meet different voltage and frequency requirements.

Electric drives, like DC motor drives, utilize power electronic converters for speed and torque control.

Induction motor drives use power electronic converters for variable voltage and frequency control to manage motor speed and torque.

Switched-mode power supplies (SMPS) in computers and chargers rely on DC-to-DC power electronic converters for different voltage requirements.

Power electronic converters are crucial in UPS systems for DC-to-AC conversion in various power ranges from home to industrial applications.

Renewable energy systems, such as solar PV farms, depend on power electronics for converting variable DC power to grid-compatible voltage and frequency.

Wind turbines require power electronic converters to transform variable voltage and frequency outputs into fixed levels for grid integration.

Electric vehicles, including cars and buses, heavily rely on power electronics for motor control and battery charging.

Wireless power charging systems use air core transformers and power electronic converters for efficient energy transfer.

Power electronic converters are designed for a wide range of applications, from watts to megawatts, requiring different circuit topologies.

The role of a power electronics engineer is to select the most suitable converter circuit for a specific application, considering efficiency and performance.

Inside a power electronic converter, components like power semiconductor devices, inductors, transformers, and heat sinks are essential for efficient operation.

The course covers theoretical concepts, simulation tools, and practical design approaches for power electronic converters.

Students will learn how to analyze power electronic converters from a design perspective, focusing on component ratings and specifications.

Understanding power semiconductor devices, gate drivers, snubber designs, and thermal management are key aspects of the course.

The course aims to enable students to design and experimentally test power electronic converters, enhancing their practical knowledge and skills.

Transcripts

Welcome to the course on Design of Power  Electronic Converters. Power Electronics  

is the electronics that is used for conversion  of power from one form to another form.  

Power may be available at a one voltage  or frequency level and we may need it at  

a different voltage and frequency level.  So, we have to convert it and power  

electronics is the means by which we do that. Power electronic converter can be represented like  

a box here as shown in this slide, you will  have the power electronic circuit inside it.  

So, on one side you may have AC or DC, if  it is DC, then the voltage level may be  

1. In the output side, we may need the DC at  another level or on the input side we may have AC  

at a particular voltage or frequency level. And on the output side, we may need it either  

in the DC form or in the AC form at a  different voltage or frequency level.  

Then what we need is the power electronic  converter. And while doing this conversion,  

we do not want to lose any energy, we want to  have maximum efficiency during this process. So,  

we would like to save maximum amount  of energy. So, power electronics is  

the electronics that is used for conversion of  power while saving maximum amount of energy.  

Before beginning the course, let us look into  some of the applications of power electronics.  

The very first application of power  electronics is in electric drives.  

This is the picture of a DC motor  drive. So, this is the DC motor  

and this contains the power electronic converter  inside. So, this will have a DC-to-DC converter  

and this DC-to-DC converter is going to do  the speed torque control of the DC motor. So,  

together we call it as the DC motor drive. Now,  different types of power electronic circuits  

may be used in this DC-to-DC converter. This picture shows an induction motor drive this  

is an induction motor drive by ABB and this is  just of a few kilowatts. So, this is the converter  

I mean inside this is the converter and the  control for the induction motor. And this one is  

the picture of an AC motor drive by Siemens. And  you can see from the picture itself, how much is  

the difference in the size, this is of this level  of megawatt level. So, this one has the motor in  

it on the bottom and at the top it contains the  converter the power electronic converter.  

Now what could be inside this kind of AC  motor drives? It could be a rectifier if the  

supply is 3-phase, so that 3-phase supply  can be rectified and converted into DC  

and then after that a DC to AC power electronic  converter can be used, we call it as the voltage  

source inverter. So, this box is just a  representation of the DC to AC conversion.  

There may be different power electronic circuits  that may be used for this voltage source inverter.  

And on this side on the output side, we will have  variable voltage and variable frequency obtained  

by controlling this voltage source  inverter. Now, this variable voltage and  

variable frequency is going to do the speed  torque control of the induction motor.  

Next application area is in DC-to-DC  conversion for SMPS applications. SMPS,  

you use it in your computers and you also use  it for different charging applications and  

different appliances we require switch mode  power conversions. Now this one is the SMPS  

that you see inside your desktop computers. You might have seen it if you happen to open your  

computer. So, what it contains inside is first  the rectification stage, it rectifies AC to DC  

and then it has the DC-to-DC power conversion  stage. Now, our computers need 12 volts,  

5 volts, 3.3 volts and so forth. And so,  all these different voltages are produced  

or obtained by using the DC-to-DC converters. Further these are chargers of your phone chargers  

and laptop chargers they are available in various  power ranges, usually these are of small power  

range from your few watts to maybe up to 30, 40  or below 100 watt these chargers are available,  

the chargers and different adapters we  keep on using it in our everyday life  

and this also contains power electronic converters  basically your DC-to-DC converters inside them.  

The DC-to-DC converters it is not that that  they are needed only for small power levels,  

they can also be needed for high power levels  in the range of few kilowatts. So, this  

is the picture of a server and servers  they also need DC power and their power  

requirements are higher in the range of kilowatt  limits. So, there we have to design DC to DC  

converter in the range of kilowatt levels. Further these are pictures of your inverters  

in UPS that comes under your DC to AC power  conversion. Now, these inverters you may be  

having at your home also. These are also made in  various power levels for your home application,  

it may be a kilowatt or a few kilowatts and  for industrial drives application the same  

inverter may be much higher level of up to  100 kilowatts or even higher than that.  

So, in various power ranges and voltage levels,  your inverters DC to AC power conversion  

is performed and the design of converters have to  be accordingly. Then, these are pictures of UPS  

uninterruptible power supply this also we keep on  using in our everyday life. This is a picture of  

the small UPS which you use for desktop computers  usually in the range of 600 watts to 700 watts.  

And then further these UPS can be of higher  power levels also in kilowatt levels. So,  

that can be used for according to  the application in industries or in a  

big area where you want to give an  UPS, bigger UPS you require it in labs.  

So, you will need big UPS. So, what  I want to say is that, that this UPS  

also contains DC to AC power conversion and also  manufactured in various wide power ranges.  

Further power electronics is also used for  renewable energy applications. Renewable  

energy like your solar and wind, they very much  depend on power electronics for power generation.  

This one is the picture of a solar  PV farm and these big farms their  

power range may be in the level of megawatt up  to 3 to 4 megawatts is what we have in India.  

So, there you know that solar PV they give power  in DC form and it is a variable DC because your  

sunlight keeps on varying, so your DC, what do you  get out of it also keeps on varying and then that  

whatever power we get that we want to transfer  it to the grid and the grid is fixed voltage and  

fixed frequency. So, it has to be converted and  that is done using power electronic converters.  

So, you may have not just one type of conversion,  but multiple conversions taking place, first the  

variable DC, then we convert it into fixed DC and  then fixed DC then can be converted into AC. So,  

this one is the picture of a grid tied inverter  and in the range of megawatt levels, where  

you may be having the kind of conversion  that I just told you. Now, solar need  

not be just used in your large farms,  they can also be put on your rooftop.  

So, there the power levels will be  in the range of kilowatt levels.  

And further it may be just like you may be just  using one panel of maybe about 100 watts. So,  

there the power level will go down to that much  and the converter has to be designed for that  

lesser power levels or you may  be using it further down for just  

some simple battery charging applications. And there the power may be much lesser than that.  

So, solar PV applications as the power levels  are very wide in which they are used, so,  

power converters also has to be designed  accordingly at different power levels.  

For wind application also we need power  electronics. So, this is a picture of a wind farm  

and in wind turbine, what you have is this your  turbine which is connected to the generator. So,  

this is called as the Nacelle of the wind turbine  and inside it contains the generator, different  

types of servo motors to control these turbine  blades and also the power electronic converter.  

So, power electronic converters various types  of power electronic converters may be used.  

Now, we know that wind speed keeps on varying.  So, you will be getting variable voltages in  

variable frequencies from your wind turbine  from your whatever generator that you are using.  

And if you want to use it if you  want to transfer it to the grid,  

we again have to convert it into fixed voltage  and fixed frequency. So, that variable voltage  

and frequency have to be converted to DC and  then that DC can be converted to AC again.  

So, this is just again to give you an idea you  can rectify it, get a DC and then use DC to AC  

power converter. Now, this is just for simplicity  I have shown it and various different types of  

power electronic converters can be used for this  purpose. And for wind applications, it is like  

medium power applications your up to your megawatt  levels, but these wind turbines are there today,  

what we see and there accordingly the power  converters have to be designed at high powers.  

After that, your electric cars this is a very,  very emerging area today, electric cars are  

replacing the conventional vehicles very quickly  

and they are heavily dependent  on power electronics.  

So, these wheels of the electric cars they are  driven by a motor and that motor is controlled  

by a power electronic converter. And then further  it has got batteries which need to be charged  

and so that charger can be inside  the car or it may be outside,  

this kind of charger may be there and that also  is actually a power electronic converter.  

And for fast charging, you need very high  levels of currents. So, accordingly the  

power electronic converters the way they have  to be designed or the circuits that you choose  

have to be such that which can supply that those  levels of currents and matching the voltage  

requirements. So, electric cars is also one of  the very big applications of power electronics.  

Next application is your hybrid electric bus. So,  hybrid electric bus it runs on diesel as well as  

on your battery power. But irrespective of  whether you are using diesel or battery power,  

it contains power electronic converters inside.  So, basically these motors, which run the wheels  

they are again driven by power electronic  converters and the batteries have to be charged  

and they also require power electronics converters  for them. So, electric vehicles is a very,  

very big application area of power electronics. Another area of application is your wireless power  

charging. So, this shows a wireless power charging  of phone. So, in it, what you generally have is  

say here you have the primary coil and, on this  side, you have the secondary coil. So, it is like  

an air core transformer it is used as a converter  which will be having a transformer in it, but  

it is an air core transformer, they are not the  normal transformer which you are used to of seeing  

it and then there will be coupling among them  and the power transfer is going to take place.  

So, basically when you put your phone on this  pad the circuit gets completed and the phone  

gets charged. Similarly, in your wireless power  charging of car you drive in and you place your  

car on this position, where below the road you may  be having the charger or via this coupling coil,  

this charger may be outside also and the  circuit again gets completed by the transformer  

and your charging of the car happens. So, it is the same thing, you have the coil here,  

you have this secondary on this side and then  you have the converters which are connected  

and then they get the power and via this  your charging is going to take place.  

So, what we see from here is that power electronic  converters they range from few watts to megawatt  

levels. Now, different applications need different  types of power electronic converters, they may be  

DC to DC, DC to AC, AC to DC or direct AC to AC.  In one type of power conversion also there may be  

multiple circuits which can be used  for a particular application.  

Now, it is the job of the power electronics  engineer to decide which of the power electronic  

circuit is most suitable for that particular  application. And many of the applications  

require multiple stages means you may having  required DC to DC then you may require DC to AC  

and so on or you may be required AC to DC  conversion and then you may be converting DC  

to DC. So, multiple stages of power conversion  may be needed for a particular application.  

Now, if you happen to look inside  a power electronic converter,  

what you will be seeing is your  power semiconductor devices,  

inductors, transformers, various types of small  electronic ICs, heat sinks and so forth. Now,  

this is the picture of an SMPS opened, you  can see here, then these are your inductors  

and then these are heat sinks, and these  capacitors and various resistors are there  

and then there is a fan as well and some wires. So, there are numerous components that are placed  

inside the SMPS. Now, this is a bi-directional  DC to DC converter designed by Texas Instruments.  

And you can see here as well the  various components that are there  

and these kind of copper bars which are also  kept here and then different ICs that are there,  

different connectors and heat sinks you can see  capacitors. So, different types of components are  

there in this bidirectional DC to DC converter. Then this is a picture of rectifying 3-phase  

inverter designed by Semikron, and this  you can see here these are your drivers,  

then these are your device modules and further  this is the heatsink and there are other many  

other components inside it. So, when you look  inside, you will see that they all appear to  

be very different in design from each other. So, you might have done a first course in power  

electronics and you may be familiar with power  electronic circuits and you may be knowing how to  

analyse those circuits. But the question is how do  you realize it practically? Because in real life,  

you need to realize them practically.  So, for that, how do you design it?  

Now, all these different applications,  they require different types of converters  

and different types of circuits may be inside  them. So, do you have to learn design of each  

one of them differently? The answer is  no. There are some common concepts which  

are applicable for all of them. So, if you learn  them, then you can apply and design the converter  

that you need for your specific application. What are you going to learn in this course? You  

will be learning the theoretical concepts related  to design. Now, usually I have seen that students  

do a first course in power electronics,  they know the circuits and then they think  

that now they can start designing that is  implementing the power electronic hardware  

without proper knowledge of the design concepts  and that usually leads to a very novice design  

and unsatisfactory performance. So, you need to know the theoretical concepts  

related to design of power electronic converters  and that is what this course plans to do. Further  

you will be also learning the simulation tools  that you can use for power electronics design.  

You will be also learning tools for  PCB designing and schematic designing  

and towards the end of the course we will  also give you demos of how to experimentally  

test a power electronic converter. So, the contents of this course are  

analysis of power electronic converters  for design. You might have analysed power  

electronic converters in the first course. But  in this we will be seeing the analysis from  

design perspective, what are those things which  you have to look into it to obtain the ratings  

and specifications of your components for design  purpose, that is what we will be covering.  

Then, we will also relook into power  semiconductor devices from design  

perspective from a practical point of view, like  how do you read data sheets, how do you choose  

specific components from design point of view.  Then, next we will be discussing gate drivers  

which can drive the different devices. Then  the snubber s design to protect devices.  

Then further we will be looking into how to do  thermal designing, thermal design basically means,  

how do you cool the devices you choose heat  sinks to maintain the temperature of the  

power electronic converter. Then the magnetics  design which means, you will be knowing how do  

you design the transformers and inductors that  are part of the power electronic converter.  

Then, this course will also give an introduction  to the problem of electromagnetic interference  

in power electronics and some of the ways of  reducing it. Further it will make you familiar  

with the power electronic hardware and a demo  will be given to you that how do you do design  

of one particular power electronic converter and  how do you experimentally test and verify it.  

So, the outcomes of this course are that after  doing this course, you will be able to do  

first design of a power electronic converter.  If you have never done any hardware design of  

power electronic converters after doing  this course, you will be able to do that  

on your own. And if you have already done some  design, you will have the knowledge of proper  

theoretical concepts of how-to do-good design  of power electronic converters. Thank you.