buck boost converter
Module
3
DC to DC Converters
Version 2 EE IIT, Kharagpur 1
Lesson
17
Types of Basic DC-DC
Converters
Version 2 EE IIT, Kharagpur 2
Instructional Objectives
Study of the following:
•
Three basic types of dc-dc converter circuits − buck, boost and buck-boost
•
The expressions for the output voltage in the above circuits, with inductive (R-L) and battery
(or back emf = E) load
Introduction
In the last module (#2) consisting of eight lessons, the various types of circuits used in both single-phase and three-phase ac-dc converters, were discussed in detail. This includes half-wave and full-wave, and also half-controlled and full-controlled ones.
In this lesson − the first one in this module (#3), firstly, three basic types of dc-dc converter circuits − buck, boost and buck-boost, are presented. Then, the expressions for the output voltage in the above circuits, with inductive (R-L) and battery (or back emf = E), i.e., R-L-E, load, are derived, assuming continuous conduction. The different control strategies employed are briefly described. Keywords: DC-DC converter circuits, Thyristor choppers, Buck, boost and buck-boost converters (dc-dc), Step-down (buck) and step-up (boost) choppers, Output voltage and current.
DC-DC Converters
There are three basic types of dc-dc converter circuits, termed as buck, boost and buck-boost.
In all of these circuits, a power device is used as a switch. This device earlier used was a thyristor, which is turned on by a pulse fed at its gate. In all these circuits, the thyristor is connected in series with load to a dc supply, or a positive (forward) voltage is applied between anode and cathode terminals. The thyristor turns off, when the current decreases below the holding current, or a reverse (negative) voltage is applied between anode and cathode terminals.
So, a thyristor is to be force-commutated, for which additional circuit is to be used, where another thyristor is often used. Later,
3
DC to DC Converters
Version 2 EE IIT, Kharagpur 1
Lesson
17
Types of Basic DC-DC
Converters
Version 2 EE IIT, Kharagpur 2
Instructional Objectives
Study of the following:
•
Three basic types of dc-dc converter circuits − buck, boost and buck-boost
•
The expressions for the output voltage in the above circuits, with inductive (R-L) and battery
(or back emf = E) load
Introduction
In the last module (#2) consisting of eight lessons, the various types of circuits used in both single-phase and three-phase ac-dc converters, were discussed in detail. This includes half-wave and full-wave, and also half-controlled and full-controlled ones.
In this lesson − the first one in this module (#3), firstly, three basic types of dc-dc converter circuits − buck, boost and buck-boost, are presented. Then, the expressions for the output voltage in the above circuits, with inductive (R-L) and battery (or back emf = E), i.e., R-L-E, load, are derived, assuming continuous conduction. The different control strategies employed are briefly described. Keywords: DC-DC converter circuits, Thyristor choppers, Buck, boost and buck-boost converters (dc-dc), Step-down (buck) and step-up (boost) choppers, Output voltage and current.
DC-DC Converters
There are three basic types of dc-dc converter circuits, termed as buck, boost and buck-boost.
In all of these circuits, a power device is used as a switch. This device earlier used was a thyristor, which is turned on by a pulse fed at its gate. In all these circuits, the thyristor is connected in series with load to a dc supply, or a positive (forward) voltage is applied between anode and cathode terminals. The thyristor turns off, when the current decreases below the holding current, or a reverse (negative) voltage is applied between anode and cathode terminals.
So, a thyristor is to be force-commutated, for which additional circuit is to be used, where another thyristor is often used. Later,