Professional Certificate of Competency in Power Electronics, Switch Mode Power Supplies and Variable Speed Drives for Electrical, Instrumentation and Control Systems

 

 

OBJECTIVES

At the end of this workshop you will be able to:

Demonstrate a sound understanding of how switch mode power supplies operate
Correctly select components and topology for a switch mode power supply
Evaluate the performance and stability of a switch mode power supply design
Demonstrate a sound understanding of how AC Variable Speed Drives (VSD's) work
Select the right VSD for a given application
Troubleshoot VSD's competently
Competently explain how flux-vector control works for drive applications
Understand squirrel cage induction motors
Identify the protection and control system requirements for VSD's
Understand the causes of motor burnout
Deal effectively with VSD harmonics and EMC/EMI problems

OVERVIEW

This course gives you a fundamental understanding of the basic components that form a SMPS design and the installation, operation and troubleshooting of variable speed drives. You will understand how the selection of components affects the different performance parameters and operation of the SMPS. Typical practical applications of VSDs in process control and materials handling, such as those for pumping, ventilation, conveyers, compressors and hoists are covered in detail. The course also covers the basic setup of parameters, control wiring and safety precautions in installing a VSD.The various drive features such as operating modes, braking types, automatic restart and many others will be discussed in detail.

The course also covers the four basic requirements for a VSD to function properly with emphasis on typical controller faults, their causes and how they can be repaired. Even though the focus of the course is on the direct application of this technology, you will gain a thorough understanding of the problems that can be introduced by SMPSs and VSDs such as ripple, harmonics, electrostatic discharge and EMC/EMI problems.


NB: The course description of all EIT "Certificate" courses has been changed to "Professional Certificate of Competency". Some course brochures are not yet updated. The actual certificate received by successful students will include the new title.
 

 

COURSE OUTLINE

MODULE 1: Introduction to Power Electronic Circuits and Devices

Introduction
Definitions and basic principles
Power diodes and thyristors
Principles of commutation
Power electronic rectifiers
Power electronic inverters
Gate commutated converters
Gate controlled devices - GTO, FCT, GTR, FET, IGBT
Block diagram of power electronic circuits

MODULE 2: Introduction to Switch Mode Power Supplies

Basic principles of PSU circuits
Linear and SMPS comparison
Comparison of topologies
Non-isolated topologies
Isolated topologies
PWM controller review
Speed critical path
Choice of topology based on power supply Specifications
 

MODULE 3: Switch Mode Power Supply Design 1

Component selection and design criteria
for input section
Input rectifiers
Input filter capacitors
High frequency transformer design
Basic transformer theory
Core material and geometry selection
Design of a power transformer for a PWM push-pull converter.
Losses and temperature rise
Winding techniques

MODULE 4: Switch Mode Power Supply Design 2

Output rectification and filtering
Power rectifier characteristics
Output power inductor design
Output filter capacitor design
Heat sinking
The thermal equation
Selecting a heatsink
Custom heatsink

MODULE 5: Switch Mode Power Control and Stability

Transfer functions
Criteria for stability
Control to output gain
Design compensation network
Control stability measurements

MODULE 6: Introduction to Variable Speed Drives

Need for variable speed drives
Fundamental principles of speed control
Efficiency, torque, inertia, horsepower/power factor
Torque-speed curves
How the motor produces torque
Types of variable speed drives

MODULE 7: 3-Phase Induction Motors

Basic construction and physical
configuration
Principles of operation and performance
Equivalent circuit and fundamental equations
Starting, acceleration, running and stopping
Power, torque and thermal rating

MODULE 8: Protection of Motors

AC frequency converter protection
Fault diagnostics
Electric motor protection
Thermal overload protection – current sensors
Thermal overload protection – direct Temperature
 

MODULE 9: Control System for AC Variable Speed Drives

Overall control system
Power supply to the control system
DC bus charging system
VSD control loops (open-loop, closedloop)
Vector control and its applications
Current feedback in AC variable speed drives
Speed feedback from the motor

MODULE 10: Selection of AC Converters for Variable Speed Drives Applications
 

Basic selection procedure
Load ability of converter fed induction motors
Operation in the constant power region
Nature of the machine load
Starting and stopping VSDs (motor braking)
How to calculate acceleration torques and times
How to select the correct motor and converter for pump and fan loads
How to select the correct motor and converter for constant torque loads, such as conveyors
Summary of the selection procedure

MODULE 11: Electromagnetic Compatibility (EMC)
 

Sources of electromagnetic interference
Noise specifications & RFI sources in SMPS
Filters for RFI suppression
Harmonics on the power supply side of AC converters
Effect of harmonic distortion on other connected equipment
Methods of reducing the effect of supply side harmonics


NB: The course description of all EIT "Certificate" courses has been changed to "Professional Certificate of Competency". Some course brochures are not yet updated. The actual certificate received by successful students will include the new title.