The main aim of the paper is to reduce the Total Harmonic Distortion of a 9-level Hybrid Cascaded Multilevel Inverter for a standalone Photovoltaic system operated at Maximum powerpoint. The maximum power point is tracked using perturb and observe (P\&O) method, a boost converter is used to implement this process. The output power is calculated using a small perturbation in the terminal voltage. The comparison between two cases of hybrid cascaded multilevel inverter using Phase Disposition Pulse Width Modulation has been done. Total harmonic distortion is minimized when one bridge is run in square wave mode and the other bridges are operated in pulse width modulation mode, according to the results of this comparison. The value of THD for HMLI output voltage is equal to 12.85 percent when all bridges are operated in PWM mode, according to simulation results. Finally, the results of the computer simulations using the MATLAB software are presented and discussed, along with a comparison of pulse width modulation strategies.