This document compares three third harmonic injected PWM strategies for controlling a 5-level diode clamped inverter: THI-IPD, THI-APOD, and THI-POD. It discusses the inverter topology, describes how a third harmonic is added to the reference signal to increase the fundamental component, and outlines the three modulation strategies. Simulation and experimental results are presented to compare the performance of the strategies in terms of output voltage quality.