This document discusses the buck-boost converter and its operation. It begins by defining the buck-boost converter as a DC-to-DC converter that can produce an output voltage greater than or less than the input voltage. It then describes the two main modes of operation - continuous conduction mode and discontinuous conduction mode. The circuit diagram and equations governing inductor current are provided. Applications mentioned include efficient motor control, long life due to lack of moving parts, smooth output control, and use in industrial equipment like trains.

1. THIAGARAJAR COLLEGE OF
ENGINEERING ,MADURAI
Dept of mechatronics
BUCK BOOST CONVERTER AND ITS
DERIVATION
M.VIGNESHWARAN
M.MOHAMMED NOORDEEN
R.PRIYADHARSHINI

2. BUCK–BOOST CONVERTER
The buck–boost converter is a type of DC-to-
DC converter that has an output voltage
magnitude that is either greater than or less
than the input voltage magnitude.

3. MODES OF OPERATION
• Continuous conduction mode
Current through inductor never
goes to zero
• Discontinuous conduction mode
Current through inductor goes to
zero

4. CIRCUIT DIAGRAM

5. The rate of change in the
inductor current (IL) ,
dil /dt=vi/l
Integrate ,
Il=vi/l(t)

7. CONTINOUS MODE

8. DISCONTINOUS MODE

9. APPLICATIONS
1. To provide efficient control on dc motor
operation
2. To provide long life and less maintenance due
to absence of moving parts
3. To provide smooth control on output,high
efficiency and fast response
4. Used in many industrial application such as
subway cars , trolly buses , battery operated
vehicle , battery charging etc.,

10. QUIZ
1. Which one of the following acts as an energy store in a DC to DC Converter?
a) The inductor b) The high frequency switching transistor c) The load d) The
flywheel diode
2 . Which of the following statements is true of a Buck-Boost Converter?
a) The output power may be less than, or greater than the input power.
b) The output voltage is always greater than the input voltage.
c) The output current is always greater than the input current.
d) The output voltage may be less than, or greater than the input voltage.
3. Name the different modes of operation in buck boost converter?