To show the feasibility of the proposed inverter topology, a hardware setup of 9-level symmetrical topology is considered. The experimental setup consists of two basic blocks connected in series with each block consists of two DC sources with equal magnitude as 16V. A rectifier unit with an isolation transformer and a capacitor filter forms the DC voltage sources. The diode IN4007 acts as a bridge rectifier unit. To get the constant voltage to the controller, IC7805 acts as a voltage regulator. The gate signals for driving the power switches has been generated with the help of 16-bit digital signal controller dsPIC30F2010. As seen from Table 5, the switches S21 and S22 were neglected and therefore 10 MOSFET (IRF840N) power switches were employed in the hardware setup. Fig. 19 shows the experimental results for the symmetric 9-level inverter. It is observed that the THD of the 9-level output waveform is achieved as 11%.
(a)
(b) Figure 19
Hardware results (a) 9-level Output Voltage and (b) THD
Conclusions
In this paper, a new topology of a symmetrical and asymmetrical type, multilevel inverter, with reduced switch count, is proposed. Different algorithms for the determination of the magnitude of the DC voltage sources are analyzed. The comparative analysis of the proposed inverter topology with other recent topologies show that the proposed topology significantly reduces the number of DC voltage sources and power switches. The advantages of the proposed topology include simple construction, ease of control, a reduced number of components, lower THD and a minimized cost. The number of on-state switches in the conduction path, are also reduced, as compared with other existing topologies. The performance of the proposed inverter topology is analyzed for 9-level symmetrical and 31-level asymmetrical cases. Finally, the feasibility of the proposed inverter
topology for 9-level symmetrical operation has been tested experimentally. The experimental results are in good agreement with the simulation results.
Acknowledgements
This research work was supported and funded by SSN Trust.
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