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Z-SOURCE INVERTER FOR ADJUSTABLE SPEED DRIVES
Presentation by
M. PURUSHOTHAM
Roll.No: 9781D5405
M.Tech (PE&ED),II Year
Under the Guidance of
G.RAVI BABU
Department of Electrical & Electronics EngineeringSRI VENTATESWARA COLLEGE OF ENGINEERING & TECHNOLOGY R.V.S.Nagar,Chittoor-517127
ABSTRACT
This paper presents a Z-source inverter system and control for adjustable speed drives (ASD).
The Z-source inverter employs a unique LC network to couple the inverter main circuit to the diode front end. The Z-source converter overcomes the conceptual and theoretical barriers and limitations of the traditional converters
INTRODUCTION
THERE EXIST TWO TYPES OF TRADITIONAL CONVERTERS
voltage-source (or voltage-fed) and current-source (or current-fed) converters (or inverters depending on power flow directions)
The voltage-source converter is widely used.
VOLTAGR SOURSE INVERTER
Fig. 1. Traditional Voltage-source converter
Fig. 2. Traditional Current-source converter
CURRENT SOURSE INVERTER
Common problems for both VSI & CSIThey are either a boost or a buck converter and
cannot be a buck–boost converter.
Their main circuits cannot be interchangeable. In other words, neither the V-source converter main circuit can be used for the I-source converter, nor vice versa.
They are vulnerable to EMI noise in terms of reliability.
Z-SOURCE CONVERTER
To overcome the above problems of the traditional V-source and I-source converters.
It employs a unique impedance network (or circuit) to couple the converter main circuit to the power source.
EQUIVALENT CIRCUIT, OPERATING PRINCIPLE,
AND CONTROL The unique feature of the Z-source inverter is
that the output ac voltage can be any value between zero and infinity regardless of the fuel-cell voltage.
The three-phase Z-source inverter bridge has nine permissible switching states (vectors) unlike the traditional three-phase V-source inverter that has eight
This shoot-through zero state (or vector) is forbidden in the traditional V-source inverter, because it would cause a shoot-through.
Fig. 9. Equivalent circuit of the Z-source inverter viewed from the dc link when the inverter bridge is in the shoot-through zero state.
Fig. 10. Equivalent circuit of the Z-source inverter viewed from the dc link when the inverter bridge is in one of the eight non shoot-through switching states.
CIRCUIT ANALYSIS AND OBTAINABLE OUTPUT VOLTAGE
Z-source rectifier/inverter system for adjustable-speed drives.
THANK YOU