This document discusses research on hybrid modulation strategies for multilevel inverters. The objectives are to develop a hybrid topology of multilevel inverters combining H-bridge and diode clamped/flying capacitor inverters, and a hybrid modulation technique combining phase disposition vertical carrier distribution and phase shifting horizontal carrier distribution to improve total harmonic distortion and reduce losses. The proposed approach combines the benefits of different multilevel inverter topologies and modulation strategies.

1. Research on Hybrid Modulation
Strategies based on General
Hybrid Topology of Multilevel
Inverter
Guided By : Mr.C.R.Balamurugan,Senior
Lect.
PROJECT MEMBERS:
S.Amanullah(50408105005)
R.Balamurugan(50408105013)
A.Manivasagan(50408105045)
M.Sai Natrajan (50408105071)

2. Why Multilevel Inverters
Due to their ability to synthesize waveforms with better
harmonic spectrum and attain higher voltages.
The multilevel inverter was introduced as a solution to
increase the converter operating voltage above the
voltage limits of classical semiconductors.

3. REASON FOR CHOSSING MULTILEVEL
INVERTERS
To increase inverter operating voltage without
devices in series
To minimize THD with low switching
frequencies fsw
To reduce EMI/RFI due to lower voltage steps
*Switching frequency for high power converters:
fsw = 60Hz ~ 1000Hz

4. SCHEMATIC OF MULTILEVEL INVERTER BY SWITCH

5. OBJECTIVE
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6. Multilevel Inverter
Topologies
1. Diode Clamped Multilevel Inverter
2. Flying Capacitor Multilevel Inverter
3. H Bridge cascaded Inverter

7. Hybrid Topologies
1. H and DCMLI Cascaded topology
2. H and FCMLI Cascaded topology

8. REASON FOR CHOSSING
HYBRID TOPOLOGY
1. Switches and DC sources are reduced
2. Better THD and EMI compared with
classical topology

9. Reason for choosing Hybrid
Modulation technique
High Performance
Low switching losses and improved quality of
Power O/P.

10. Modulation Strategy Employed
Multi-Carrier SPWM
1) The Vertical Distribution Technique
a)PD
b)APOD
c)POD
2) The Horizontal Phase-Shifted Technique
a)PS

11. Proposed Hybrid Modulation
technique
Combination of vertical distribution
technique (PD) with the Horizontal Phase –
shifting technique (PS)
*PD is chosen because of its best Harmonic profile.