POWER ELECTRONICS TRAINERS

Advanced Learning Environment for

Power Electronic Devices

Introducing FE Power Electronics Trainers

FE Power Electronics Trainers make sure that whatever

knowledge that remained out of students’ grasp so far,

becomes easy and available to them,

boosting their confidence to venture into applications

using power electronic devices.

Frontline Electronics launched a series of next generation

trainers to take up study on power electronic devices

and applications with ease and confidence.

These trainers come with many

first-of-its-kind features creating right study environments

to gain required insight on the working principles

of these devices in all operating conditions.

Then, the application trainers guide the students

on applying these power devices in selected

applications with all the required experimental facilities.

These trainers enable the students focus on

acquiring working knowledge on these power devices

and make them ready to apply these devices

in real-life applications in short time with certainty.

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Tricky Measuring and Monitoring Requirements

Another disadvantage of using many external power supplies and oscilloscopes is the common

ground potential of all these facilities. Normal oscilloscopes come with two or more channels

sharing same ground which is connected to the mains earth. Because of this, more than one

floating measurement is not possible; provided the power supplies are isolated and non-

grounded. If the students, without this understanding, connect the negative lead of the probes at

different places, the circuit may get short conditions, resulting in damage to the circuit and/or

the oscilloscope. If the used power supplies have the mains earth connected to the supply ground

(as most bench power supplies are), not even one floating measurement is possible.

Generally, students start collecting available power supplies to take up the study on the power

electronic devices. They wire up these supplies with the power devices in the usual way; one

supply giving the main device supply V and another powering up the gate. The outputs

of these supplies are defined by analog potentiometers used in the supply control circuitry.

Because of this design configuration, the exact precision may not be available to create the

required test conditions. Normally labs don’t give students high valued precision power supplies

which could create the precision operating environment.

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When students take MOSFET/IGBT devices into study, required gate voltage varying range for

the active region is very small, about 200-300mV. When the device gets into active region,

they need high resolution power supplies and measuring facilities to plot multiple output

characteristics waveforms within this active region.

Apart from creating an ideal operating environment for the power devices, students also

need precision measuring facilities to complete the scene. To make an effective study on the

characteristics, student requires up to five multimeters with minimum 3.5 digits of resolution.

Also, the maintenance of A resolution current meters is very difficult in a college lab setup

because they are easily damaged when the current limits are exceeded. Giving this kind of

facilities to all the students of the class is real expensive problem to any laboratory.

When using ordinary power supplies, current based triggering devices like SCR and TRIAC,

demand constant maintenance of gate current at the defined level during the experiment. With

these power supplies, if the V voltage is varied during experimentation, gate current also gets

changed from its set value. Then, the student goes back to the gate power supply to adjust the

current to its initial set value. This happens for every change of V voltage. Till the device gets

triggered with the exact parameters, the student has to shuttle back and forth between the supply

voltages. While repeatedly adjusting the gate current manually using an analog potentiometer,

the student inadvertently triggers the device in random. The student fails to understand the

device’s exact triggering point and ends up seeing the device in triggered condition in surprise.

Not understanding this may become disadvantageous when creating control algorithms for the

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device in power applications.

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Also, viewing the current waveforms of the power application circuits, particularly Buck and

Boost convertors is very difficult without the use of isolated current probes, which are again

very expensive. Without viewing the current waveforms, the student cannot understand the

exact operating conditions of the circuit, particularly the continuous and discontinuous modes

of operation, making the study incomplete.

Another concern when using multiple power sources, measuring instruments and oscilloscopes

is the accidental shorting or wiring mistakes which can damage the power devices. It is very

difficult to identify the dead devices when the operating conditions are complicated as above

discussed. Also, periodic maintenance and replacement costs become expensive during the

usage of these setups. It has been observed in many institutions, power electronics device study

arrangements are not very encouraging to both students as well as lab maintenance staff.

Intelligent Study Environment

As we know now, fully controlled power supplies and the precision measuring features are very

much required to create an intelligent study environment to understand the operating secrets of

these power devices. FE’s range of trainers come with built-in power sources, all required

measuring facilities along with LCD based oscilloscope features making the study a convenient

one to the students.

In the Power Electronic Device Characteristics Trainers, the students can set operating voltages

with the resolution of 10mV, then define the current source with resolution of 10 A easily with

rotary encoders and switches thanks to the digital control implementation within the design.

Likewise, the measuring facilities help the students measure all the operating parameters with

a voltage resolution of 10mV and current resolution of 10 A at all the required points.

However, there is a solution

available for this, albeit a very expensive

one. High-voltage Active Differential Probes are

available to mitigate isolation problems. But the cost of each

probe is usually more than many entry level DSOs. The cost of supplying oscilloscopes

with two high voltage active differential probes to every batch of students becomes prohibitive

for most educational institutions.

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The Trainers include a modular application circuitry with multiple

controlling/triggering options to enable the students try out multiple design concepts in many

combinations to ensure maximum learning in the given time. Based on the applications, multiple

triggering possibilities, multiple loads, a range of capacitor and inductor options extend the

learning flexibility of the students.

Power Electronic Application

The trainers come with an integrated stand-alone two channel differential oscilloscope functions

using TFT colour LCD with professional encoders creating facility to view and measure the

important voltages and currents of the circuit to help students get a thorough understanding on

the device operations. The trainers support two channels of fully differential inputs to facilitate

two simultaneous floating measurements during the study. Measurements by these channels

include mathematical functions like Peak-to-Peak, RMS, Mean, Maximum and Minimum on

the input signals. The scope function also supports 12-bit resolution comparing to regular

oscilloscopes coming with 8-bit resolution.

The trainer also has Auto-Plot modes which enable the user to view textbook waveforms

of the V-I characteristics instantly. One voltage/current source is set to a constant value by the

user while the other is automatically varied from zero to maximum and the required parameters

are measured. The value of the variable parameter is plotted against the measured parameter.

A maximum of five plots will be displayed in the screen, each in different colour.

The Auto-Plot function is a well-thought facility introduced to give the students much required

confidence and motivation to start and pursue the study without any doubts by presenting the

textbook waveforms at the press of a button. This function just demonstrates the working of the

target device in all the operating modes without giving any reading of the exact voltages. When

the students become sure of exact device operations, they may put their heart into deep learning

and gain confidence in using the target devices in more of their future applications.

As the result, the students’ attention is focused more on understanding device operations than

on creating the required operating conditions and they learn more onthe device in the given time.

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Whatever study remained complex

and impossible all these years become easy

and convenient to the students and they get quick

confidence on using the power devices further in their applications.

Then comes another important feature; the target device is securely protected against any

inadvertent shorts or mis-wring by the students. The careless handling of gate power supply can

easily damage the device. FE trainers take care of the target devices with total protection and

zero maintenance, saving the labs from periodic costly maintenance.

As a whole, FE trainers give an intelligent study environment making the complicated study a

simple one and help the students gain the required understanding and motivates them to try

more in the next stage of their career.

APPLYING POWER DEVICEWITH CONFIDENCE

HIGH RESOLUTIONFLOATING MEASUREMENTS

TEXTBOOK WAVEFORMGENERATIONS TO KEEP

STUDY IN FOCUS

INTELLIGENT USERINTERACTION FACILITIESTO CREATE A VAREITY OF

STUDY ENVIRONMENTS

PROGRAMMABLEHIGH RESOLUTION

VOLTAGE/CURRENT SOURCES

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The study of characteristics of devices like MOSFET, IGBT, SCR and TRIAC and understanding their

operating principles become important when using these devices in power applications.

FE’s line of trainers guide the students in this study with right experimental environment. The

trainers come with Programmable high resolution voltage/current sources, supported with high

resolution measurements. Built-in facility is available to plot textbook waveforms for the target

devices using Auto-Plot function. This feature ensures the students about the good health of the

target device and motivates them to take up the study without any hesitation. Smart and versa-

-tile interacting features using graphical LCD, encoders and switches invite students to explore

more during their study and understanding.

Characteristic Study

Programmable Voltage Source - VCC

This programmable voltage source V is a digitally controlled power supply whose output can

be varied from 0 to 25V in steps of 10mV. The voltage can be set by using an encoder and the

value is displayed in the LCD. Both the set and measured voltages are displayed. For bidirect-

-ional devices, 25V range is available.

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Programmable Voltage/Current Source - V / IG G

A programmable voltage or current source is available as per the requirement of the target

Device Under Test(DUT). For the voltage controlled DUT, voltage source is available; the

current controlled DUT can make use of the on-board current source.

Voltage source V is a digitally controlled power supply whose output can be varied from 0 to

15V in steps of 10mV. The voltage can be set by using an encoder and the value is displayed on

the LCD. Both set and measured voltages are displayed on the LCD.

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ANODE

CATHODE

GATE

IGVG

IL

Voltage Measurements: V , V and VCC G AK

Voltage measurements required for V , V and V are made using high precision analog

circuitry giving 3.5 digits resolution. All the measured voltages have a minimum resolution of

10mV and they are all displayed on the LCD.

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Current Measurements: I and IL G

Current measurements for I and I are made using high precision analog circuitry. measurement

has a minimum resolution of 10 A while measurement sports a minimum resolution of 1mA.

L G I

I

G

L

The current source I is a digitally controlled power source whose current can be varied from

0 to 15mA in steps of 10 A. The current value can be set by an encoder and is displayed on

the LCD. Both the set and measured current are displayed on the LCD. For bidirectional devices,

15mA range is made available.

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Intelligent User Interface

The User Interface of the trainers consists of a TFT LCD displaying the measurements and

graphs. A set of encoders and switches help the students define the required operating voltage in

convenient ways. The trainers have two operating modes: Measurement Mode and Auto-Plot Mode.

Measurement Mode: In the measurement mode, two programmable voltage/current sources can

be digitally controlled and all the voltage and current measurements at important points of the

circuitry are displayed.

Auto-Plot Modes: In the Auto-Plot modes, V-I characteristics graphs of the DUT are plotted in

real-time at the press of a button. A maximum of five plots will be displayed in the LCD, each in a

different colour.

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The MOSFET is a voltage controlled device whose

drain-source resistance varies with gate-source

voltage. To understand the device characteristics,

a V power supply of 0-25V and a V voltage

supply of 0-15V are made available in the trainer.

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FEPET01 - Study of MOSFET characteristics FEPET02 - Study of IGBT characteristics

The power electronic device, IGBT is also a voltage

controlled device with an output characteristics

similar to a BJT. To proceed with the study on device

characteristics, a V voltagesupply of 0-25V and a

V voltage of 0-15V are provided within the trainer.

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FEPET03 - Study of SCR characteristics

SCR is an unidirectional thyristor which gets

triggered by the application of positive current to

the gate. To study this device, a V voltage

of 0-25V and a I current source of 0-15mA are

designed into the trainer.

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supply

FEPET04 - Study of TRIAC characteristics

TRIAC is a bidirectional thyristor which gets activated

by a positive or a negative current through the gate.

To start the study on this device, a voltage supply

of 25V is used for V and a current source of 15mA

is provided for I .

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Study of Power Electronic Devices in Applications

FE has a line of trainers enabling students understand how power electronic devices are put into

selected applications. Trainers include modular circuitry with multiple controlling/triggering

options guiding students’ experiments with multiple design concepts in the applications to

ensure maximum learning in the given time. The trainers come with multiple triggering choices,

multiple loads, multiple passive component options to enhance the knowledge acquired.

The trainers are complete in all respects and they can be used as a stand-alone experimental

environment without requiring any other external T&M support. They come with built-in two

channel differential oscilloscope features required to view and measure all the voltages and

currents at the important locations to get a thorough understanding of the design concepts in the

most convenient way. On-board TFT colour LCD and professional encoders provide an unmatched

study interaction to the students. Mathematical measurement facilities like finding Peak-to-

Peak, RMS, Mean, Maximum and Minimum are available to understand more on target signals.

The oscilloscope function supports two simultaneous floating measurements through differential

input sensing facilities.

SelectablePassive

Components

SelectableLoad

SwitchingDevice

AC/DCPowerSupply

PassiveTriggering

ActiveTriggering

MicrocontrollerTriggering

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The scope functions have high resolution measurements with 12-bit capability as opposed to

common oscilloscopes of 8-bit resolution, resulting in high resolution and accurate

measurement on the input signals during the study.

The trainer’s application circuitry is designed to protect the target device in case of any inadvertent

shorts, mis-wiring by the students. Total design is optimised for college lab environment and is

designed to provide a long working life with zero maintenance.

FEPET05 - Trainer for SCR Single Phase AC Power Control

In this experimental environment, half wave AC

power control is implemented using an SCR. The

SCR is grounded and the load is connected in a

floating configuration enabling direct connection

to different triggering circuits.

A

resistive load and lamp load are also available

on-board for experiments. Students can connect

these loads and triggers to application circuits

using patch cords.

Five types of

triggering are available here: R, RC, UJT, Op-Amp

based and Microcontroller based triggering.

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FEPET06 - Trainer for TRIAC Single Phase AC Power Control

In this experimental environment, bidirectional

AC power control is implemented using a TRIAC.

The TRIAC is grounded and the load is connected

in a floating configuration enabling direct

connection to various triggering circuits. Five

types of triggering are available here: R, RC, UJT,

Op-Amp based and Microcontroller based triggering

A resistive load and lamp load are provided

on-board. Students can work with these loads

and triggering to examine the given application

in the most effective ways.

FEPET07 - Trainer for SCR Half Controlled/ Full Controlled Rectifier

In this experimental study, half and full wave controlled

rectification is implemented using SCR. The load is

grounded and the switching device is left floating.

Therefore a pulse transformer is available to isolate the

triggering from the target device. Students have the

choice of choosing either an SCR Bridge or a single SCR

for rectification. UJT triggering is provided with a suitable

multi-winding pulse transformer for triggering up to four

SCRs simultaneously. The students can connect various

parts of the circuitry using patch cords.

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FEPET08 - Trainer for MOSFET Based Buck Converter/Chopper

Here, a Buck converter is implemented using a

MOSFET. Microcontroller based digitally controlled

PWM signals are provided with proper gate drive

circuitry for driving the MOSFET. The PWM frequency

can be varied from 1kHz to 10kHz and the duty

cycle can be varied from 5% to 95% using an

encoder. Multiple inductors, capacitors and load

resistors are provided to the students to try out

various designs and implementations. The students

can make the circuit operate in either continuous

conduction mode or discontinuous mode by varying

the circuit components and/or the PWM parameters.

Students can use patch cords to establish their

study environment for the more learning in the

given time.

FEPET09 - Trainer for MOSFET Based Boost Converter/Chopper

In this experimental environment, a boost converter

is implemented using a MOSFET. Microcontroller based

digitally controlled PWM signals are provided with

proper gate drive circuitry for driving the MOSFET.

The PWM frequency can be varied from 1kHz to 10kHz

and the Duty Cycle can be varied from 5% to 60%

using an encoder. Multiple inductors, capacitors and

load resistors are provided to the students to explore

various design possibilities and implementations. The

students can make the circuitry operate in either

continuous conduction mode or discontinuous conduc-

-tion mode by varying the circuit components and/or

the PWM parameters.

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Frequently Asked Questions

How is Auto-Plot facility useful?

Why is a constant-current power supply essential to take up the study of SCR and TRIAC?

Theoretically, SCR and TRIAC are current triggered devices and a constant-current power supply is

very much required to maintain gate current at a constant value when the anode-cathode voltage is

being varied. If a simple voltage power supply is used for this purpose, the gate current will vary

every time the anode-cathode voltage is changed. The students have to adjust the gate current to

the set value for every change of anode voltage and this may cause an inadvertent triggering of the

device. Students may miss the exact triggering points which may become disadvantageous when

designing control algorithms for these devices in their applications. Without constant-current gate

power supplies, plotting the accurate characteristic graphs of SCR and TRIAC is very much difficult.

What is the significance of the current waveforms in power electronics application study?

During the study of Buck and Boost Converters, the current waveforms of the inductor and the

switches are essential to understand the circuits in continuous and discontinuous modes of operations.

High frequency current probes are very expensive and difficult to use. FE's trainers have on-board

current measurement facility to enable the students view current waveforms which can otherwise be

seen only in the textbooks.

What are the advantages of the built-in oscilloscope over external oscilloscopes?

The built-in two channel oscilloscopes of FE's application trainers are designed for precision and

convenience rather than regular oscilloscopes which are built for speed. The in-built oscilloscope

supports 12-bit resolution, differential voltage and current measurements enabling students view

two voltage/current waveforms simultaneously. The oscilloscopes also come with mathematical

functions like Peak-Peak, RMS, Mean, Minimum and Maximum on the acquired waveforms. External

oscilloscopes are not capable of differential voltage measurements or high frequency current

measurements without expensive active probes.

Why high precision measurements and power sources are required?

In the device characteristics study, the range of gate voltages and currents required for making the

device operate in active region for V-I characteristics study is very small: around 200mV to 300mV

for MOSFETs/IGBTs and around 50µA to 100µA for SCRs/TRIACs. Without precision power supplies

and measuring facilities, obtaining multiple V-I characteristics plots is out of question.

In power electronics application study, precision measurement facility is required to cross-verify

theoretical design calculations with practical results. The 12-bit in-built oscilloscope is more suitable

for measuring mathematical parameters of current and voltage waveforms than an external 8-bit DSO.

When testing any external device, the Auto-Plot facility is useful to understand the characteristics of

the target device without any difficulty and motivates the students to apply the device in their

applications with confidence.

The Auto-Plot facility enables the students to generate textbook V-I characteristic waveforms for the

target power devices at the press of a button. This facility confirms the students about working of

the target device and motivates them to study the intricacies of the device characteristics. Since the

measurement readings of these Auto-Plot graphs are not available to the students, they are expected

to re-create them manually to improve their understanding.

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When using FE trainers, won't the students miss out on the assembly and troubleshooting

skills that come with breadboard or other assembly options?

Study of power electronic device characteristics requires high precision power supplies along with

multiple multimeters for every experimental setup. The cost of the equipment and the difficulty in

maintaining them, especially, the µA current range multimeters/ammeters which tend to be damaged

very easily, is prohibitive for most college labs. Usually, compromises are made during experimentation

and the students have to set up the study with only available low-end T&M equipment which defeats

the learning process.

For the application experiments, a complete study requires complicated circuitry which cannot be

assembled in the breadboards or DIY boards in reasonable time. So, advanced triggering/control

circuits cannot be studied during the lab sessions. Also, the students cannot make differential voltage

or current measurements with external oscilloscopes unless extremely expensive active probes are

made available to them. When students have more time for learning, FE trainers support them with

more options in load, triggering, applying different passive devices to continue their study that result

in enhanced learning.

Moreover, with manual breadboard assembly, the students have to spend significant time in assembling

and troubleshooting the circuits that leaves very little time for the required learning. There are other

electronic labs where the students can learn about electronic assembly and troubleshooting. But, for

the power electronics lab, the students are at the risk of missing out on the key concepts which may

prevent them from exploring further in power electronics.

As a whole, FE trainers provide an ideal learning environment to the students which boosts acquired

knowledge, more than expected in power electronic study in any lab.

What makes FE power electronic trainers better than other options with low integration?

Besides the Auto-Plot and constant-current power supply features, FE Power Device Characteristics

Trainers also have high precision digitally controlled power supplies along with on-board high precision

3.5 digit resolution current and voltage meters.

FE Power Electronics Application Trainers have built-in two-channel high-resolution differential oscilloscope

with voltage/current measurement and mathematical calculation facility. The application circuitry is modular

and user-configurable with multiple triggering/controlling and passive device options.

Everything is integrated into a single stand-alone solution with a convenient and intuitive user-interface

using a TFT colour LCD combined with professional rotary encoders and switches. The circuitry is given

adequate protection against inadvertent mis-wiring and shorts, giving long working life with zero

maintenance.

Simple trainers with low integration do not have any of the above mentioned advanced features and

only provide analog power supplies with or without low precision analog or digital voltmeters/ammeters

for characteristics study and simple circuitry with limited triggering options for application study. They

do not provide any significantly better learning than manual breadboard assembly. This discourages the

student from getting a thorough learning in power electronics; missing confidence to apply these

devices in further applications.

This is particularly significant for buck and boost converter designs where parameters like inductor

ripple current, average inductor current and output voltage ripple are to be measured.

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Frontline Electronics Pvt. Ltd.,

Pandian Street, Alagapuram, Salem - 636 016, Tamilnadu, India.

Phone : +91 427 2449238/95855 53542

www.Frontline-Electronics.com

E-mail : feplslm@frontlinemail.com/feplslm@gmail.com

For more details, Contact:

M. Ramkumar,

Senior Marketing Manager,

Phone : +91 95666 57090.