A 15-Level Asymmetric Cascaded H Bridge Multilevel Inverter with Less Number of Switches For Photo Voltaic System


This Paper presents a 15 level Asymmetrical Cascaded H bridge multilevel inverter Topology for Photovoltaic system. In this system Symmetrical and Asymmetrical Multilevel inverter (MLI) is utilized. In Symmetrical MLI, the DC source magnitude are equal ie., 50Vdc, 50Vdc & 50Vdc., where as in Asymmetrical MLI the DC source Magnitude are unequal and it is designed with binary form of voltage such as 50Vdc, 100Vdc & 200Vdc.Comparing both the MLI , Asymmetrical MLI generates a number of output voltage level with same number of Power semiconductor switches. The phase Disposition Pulse Width Modulation (PD-PWM) technique is used for controlling the Power semiconductor switches in MLI. The results are verified in both MATLAB and PROTEUS.



  1. Photo voltaic system(PV)
  2. Symmetrical MLI
  3. Asymmetrical MLI
  4. PD-PWM
  5. PIC16F877A
  6. IR112



A symmetrical Cascaded H bridge Multil level inverter(SCHBMLI) and Asymmetrical Cascaded H bridge Multilevel Inverer(ASCHBMLI) has been analysed in this paper. Both the Inverter consist of the same power semiconductor switches but the output voltage levels are different. In SCHBMLI the ouput voltage is 9 level , while ASCHBMLI the ouput voltage levels are 15 level. The THD analysis for ACHBMLI using the switching technique of high switching frequency (2KHz) PD-PWM is 6.03% and the switching technique of low switching frequency(50Hz) is 10.26%. In this system the THD is very less by using PDPWM technique.This type of system is used for high power applications for photovoltaic system bec it reduce the overall cost and size of the system


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