1. MULTILEVEL INVERTERS
By Vaishnavi

2. NEED FOR MULTILEVEL INVERTER
High Power application
Staircase waveform
Input Current
Switching Frequency
Renewable Energy sources
Only disadvantage – More Switches, Cost

3. BASIC CONCEPT Use of Power Semiconductor
Switches in series - with several lower
voltage dc sources - staircase voltage waveform
Lower voltage dc sources
– Capacitors, Batteries, PV cells

4. TYPES OF MULTILEVEL INVERTERS
Diode Clamped Multilevel Inverter
Flying Capacitor Multilevel Inverter
Cascade Multilevel Inverter

5. DIODE CLAMPED MULTILEVEL INVERTER
Let, m  number of nodes or levels
Then, We require,
(m-1)  Capacitors
2(m-1)  Switching Devices
Example :-
m= 6
Therefore,
Capacitors – 5
Switching Devices - 10

6. CIRCUIT DIAGRAM OF 6- LEVEL INVERTER

7. SWITCHING STATES

8. LINE VOLTAGE WAVEFORM OF SIX LEVEL CONVERTER

9. FEATURES OF DIODE CLAMPED INVERTER
High Voltage rating for blocking diodes
Unequal Switch device Rating
Capacitor Voltage Unbalance

10. Advantage & Disadvantage
ADVANTAGES
Harmonic Content is
less-filters avoided
Efficiency – High
Control method - simple
DISADVANTAGES
Difficult to control the
real power of individual
converter
Need for more
clamping diodes

11. Thank You