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.
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.
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.
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