Performance and Thermal Reliability Comparisons of 2-Level and 3-Level NPC Voltage Source Inverters for Electric Vehicle Drive Applications

Thesis Type: Postgraduate

Institution Of The Thesis: Middle East Technical University, Faculty of Engineering, Department of Electrical and Electronics Engineering, Turkey

Approval Date: 2019

Thesis Language: English

Student: Alican Madan

Supervisor: Emine Bostancı


Two-level and multilevel inverters are widely used in electric vehicle drive applications with different switching techniques. Selection of the topology and the switching technique for electric vehicle drives are getting more important with the trend of designing more compact and more efficient drive circuitry. Reliability of semiconductors in power electronics are under investigation in recent years as well. In this thesis, a multidimensional comparison of two common topologies for a 120 kW electric vehicle PMSM (Permanent Magnet Synchronous Machine) drive system is conducted. Two-level topology and three-level NPC (Neutral Point Clamped) type voltage source inverters are compared in terms of output voltage and current quality, thermal performance, efficiency, switching frequency limitation and semiconductor
thermal reliability aspects. Also SPWM (Sinusoidal Pulse Width Modulation) and SVPWM (Space Vector Pulse Width Modulation) techniques are under investigation.