مشخصات پژوهش

Minimization of Total Harmonic Distortion (MTHD) for the line-to-line output voltage of multilevel inverters has been studied in this work. Harmony Search (HS) Algorithm with artificial neural networks (ANN) has been employed to solve the aforementioned problem with considering constant and alterable DC sources in order to minimize Total Harmonic Distortion more efficiently. The nearest solutions provided by HSA obtain a smooth data set that is desired for the neural network training. MTHD is suitable for some cases, e.g. multilevel electrical drives and flexible AC transmission system devices such as multilevel static VAR compensator, multilevel unified power quality conditioner and multilevel unified power flow controller, where DC link voltages are altering. MTHD not only optimizes the switching angles, also finds the optimum values for DC links. In this work THD minimization with employing both constant and alterable DC sources has been researched and compared with each other. Also a comparison is made with a recently published paper using GA, which validates that the proposed scheme is more efficient in this regard. Numerical results for a test case, seven-level inverter, reveal that the presented method is feasible.