Download 1:M Power Input Power Output - Electrical and Computer Engineering

CHAPTER 1
INTRODUCTION
Any power semiconductor system employed for rectifying, inverting, or otherwise modulating
the power output of an ac or dc energy source is called a “CONVERTER SYSTEM” or “POWER
CONDITIONING SYSTEM”.
Objective: Adjustable ratio transformer:
DC-to-DC, DC-to-AC, AC-to-DC, AC-to-AC
DC
DC
AC
AC
1:M
Frequency = f2
Frequency = f1
Control
STATIC CONVERSION OF ELECTRICAL ENERGY FROM ONE FORM
TO ANOTHER TO SUIT SPECIFIC REQUIREMENTS;
TO BE ACHIEVED IDEALLY WITH 100% EFFICIENCY.
REALIZATION
Power Electronic Converter
Power Input
Power Output
To the Controlled System
(Example: DC Motor,
Computer, Lamp ..)
CONTROL
ELECTRONICS
(Analog/Digital,
Microprocessors
DSPs....)
Feedback Signals
(Speed, Voltage, Current,
etc.)
Fig. 1.1 Realization of power conditioning system.
Bhat Ashoka
ELEC410
Chapter-1
Introduction
1.1
Transformer Isolation:
To step-up or step-down to match the load requirements & safety requirements.
1. Line-frequency (60 or 50 Hz) transformers – bulky and costly.
2. High-frequency (1 kHz to several hundreds of kHz) transformers – Small
size, light weight and low cost.
Types of Converter Systems:
Type of conversion
1. AC-to-DC
RECTIFIERS (Uncontrolled)
Fixed ac to Fixed dc (Line
(Diodes)
Commutation)
RECTIFIERS (Controlled)
Fixed ac to Fixed or Variable
(SCRs, IGBTs, MOSFETs,
GTOs ...)
dc (Line or Forced
Commutation)
2. DC-to-DC
3. DC-to-AC
Fixed (or variable) dc to
Variable (or fixed) dc
Inverters (Uncontrolled)
Fixed voltage dc to Fixed ac
Inverters (Controlled)
Fixed (or variable) dc to
Variable ac
4. AC-to-AC
AC Voltage Controllers
Fixed to variable ac
Cyclo Converters
Fixed ac to variable voltage &
frequency (usually less than
input frequency)
Bhat Ashoka
ELEC410
Chapter-1
Introduction
1.2
TABLE 1.1
Power Electronic Applications
(1) Residential
Space heating, Refrigeration and freezer, Air conditioning
Cooking, Lighting (dimmers, CFL, LED lamps ..)
Electronics (personal computers, battery chargers, other entertainment equipment)
(2) Commercial
Heating, ventilating, and air conditioning, Central refrigeration,
Lighting, Computers and office equipment,
Uninterruptible power supplies (UPS), Elevators
(3) Industrial
Pumps, Compressors, Blowers and fans, Machine tools (robots), Arc furnaces,
Induction furnaces, Lighting, Industrial lasers, Induction heating, Welding
(4) Transportation
Traction control of electric vehicles, Battery chargers for electric vehicles
Electric locomotives, Street cars, trolley buses, Subways
Automotive electronics including engine controls
(5) Utility systems
High-voltage dc transmission (HVDC), Static VAR generation (SVG)
Alternative energy sources (wind, photovoltaic, fuel cells, ..)
Energy storage systems, Induced draft fans and boiler feed water pumps
(6) Aerospace
Aircraft power systems, Space shuttle power supply system, Satellite power systems
(7) Telecommunications
Battery chargers, Power supplies (dc and UPS), Cell phones
[Source: Mohan etal., “Power Electronics”, Book, 2003 and other]
Bhat Ashoka
ELEC410
Chapter-1
Introduction
1.3