It gives the basic Idea about Inverter than moving towards the advantages of Multilevel Inverter .In this PPT main focus on Flying Capacitor Multilevel Inverter.

1. ADVANCED POWER ELECTRONICS
SHEIKH MOHAMMAD SAJID
RCoEM
M. TECH 1ST Sem
Roll no - 07

2. INVERTER
 Inverter converts DC volatge into variable magnitude
and variable frequency AC voltage.
 Ideally , Purelly sinusoidal output voltage.
 Practically not possible.
 PWM technique makes the task of extracting
sinusoidal voltage from the output of inverter easier.

3. 3-PHASE FULL BRIDGE VSI

4. 3-
PHASE
FULL
BRIDGE
VSI
WAVEF
ORM

5. ADVANTAGES OF MULTILEVEL
INVERTER
1. Reduced harmonic distortion- Multilevel converters
not only can generate the output voltages with very low
distortion, but also can reduce the dv/dt stresses,
therefore electromagnetic compatibility (EMC) problems
can be reduced.
2. Common-mode(CM) voltage- Multilevel converters
produce smaller CM voltage; therefore, the stress in the
bearings of a motor connected to a multilevel motor drive
can be reduced.
3. Input current- Multilevel converters can draw input
current with low distortion.
4. Switching frequency- Multilevel converters can operate
at both fundamental switching frequency and high
switching frequency PWM. It should be noted that lower
switching frequency usually means lower switching loss
and higher efficiency.

6. FLYING CAPACITOR MULTILEVEL INVERTER
 This inverter uses capacitor to limit the voltage of
power devices. The configuration of the flying
capacitor multilevel inverter is like a diode clamped
multilevel inverter except that capacitor are used to
devide the input DC voltage. The voltage over each
capacitor and each switch is Vdc.

7. FLYING CAPACITOR 3 LEVEL INVERTER

8. FLYING CAPACITOR 3 LEVEL INVERTER

9. FLYING CAPACITOR 5-LEVEL INVERTER

10. FLYING CAPACITOR 5-LEVEL

11. COMPONENT COUNT OF FLYING
CAPACITOR
The number of components in one leg of inverter are as follows:
Number of active switches =2*(m-1)
Number of flying capacitors = (m-1)
Number of cascade capacitors = {(m-1)(m-2) }/2

12. ADVANTAGES
1. Real as well as active power flow is controlled.
2. Since more number of capacitor are used, short
duration outages and voltage sag does not affect
much as load side.
3. Low harmonic content.
4. Redundancies are available to balance different
voltage levels.
1. Large number of capacitors make inverter bulky.
2. Inverter content is very complicated.
3. Poor efficiency for real power transmission.
DISADVANTAGES

13. APPLICATIONS OF MULTILEVEL INVERTER
 High-voltage and Medium-voltage motor drives
 High voltage DC transmission
 Flexible AC transmission system (FACTS)
 Traction
 Active filtering
 Utility interface for renewable energy systems