Voltage
Source Inverter (VSI)
•Inverter
is device which converts Direct Current (DC) to Alternating Current (AC).
•There
are two types of inverters one is Voltage
source inverter (VSI) and second is current source
inverter (CSI).
•Voltage
source inverter keeps the voltage
constant.
•Current
source inverter keeps the current
constant.
•Voltage
source inverter (VSI) consists of one dc voltage source, transistors for switching, and one large dc link capacitor.
•DC
source may be a battery, Dynamos or Solar cell.
•Transistor
may be IGBT, BJT, MOSFET, or GTO.
•For
Direct Current the large DC link capacitor acts like open circuit and for high
frequency AC the capacitive
impedance is low.
•VSI
may be single phase bridge circuit or three phase bridge circuit.
•Single
phase bridge circuit consist of two legs of switches each leg consist of upper and lower switch.
•Antiparallel diode is use to allow non-unity power
factor load at output.
•The
single phase VSI consist of two
load terminals and
three phase VSI consist of three
load terminals.
