Khajeh-Shalaly, B., Shahgholian, G.. Design and Analysis of a Novel Robust and Fast Sliding-Mode Control with Multi-Slope Sliding Surface for Single-Phase Three Level NPC Inverters under Different Loads and Reduce the Output THD. Nashriyyah -i Muhandisi -i Barq va Muhandisi -i Kampyutar -i Iran. 2017;15(2):103-113.