Slew Rate Control Optimisation for Gate Driver Circuit of NPC Multilevel Inverter
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Electric power engineering (MPEPO), MSc
Publicerad
2024
Författare
Srivastava, Harsh
Ganesh, Subramanian
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Abstract
Electric Vehicles (EVs) introduce unique challenges in managing Electromagnetic Interference (EMI) due to the coexistence of high and low voltages within confined spaces. At the same time, there is the need for increased efficiency of the propulsion system in order to increase the range of the EV, which means application of high-switching-speed power electronics and the introduction of wide-bandgap technologies. The overarching objective of this study is to attain optimal EMI levels within the EV’s electromagnetic environment by exploring the application of multilevel inverters (MLI) based on wide-bandgap switches and optimized gate driver design with a central focus on better EMI performance and energy efficiency. The proposed approach involves refining switching techniques of Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) to strike a balance between switching rates and EMI generation. Rapid switching, while reducing losses, can lead to increased switching transients and magnetic fields, which contribute to EMI. A pivotal element of this research is the design of a gate driver circuit with controlled slew rates, specifically tailored for The Neutral Point Clamped (NPC) converter. Each switch in the inverter has been prefixed with a custom gate driver as per its slew rate. The investigation commences with a meticulous analysis of a three-level inverter, encompassing diverse driver circuit simulations. Subsequently, the developed gate driver design is implemented in a 3-level inverter configuration. This choice aligns with multilevel inverter principles, enabling efficient operation at higher voltage levels compared to traditional two-level inverters. NPC converter topology, widely embraced in machine drive applications, forms the bedrock for these experiments. To assess the efficacy of the proposed solution, a rigorous evaluation of modulators, including Sinusoidal Pulse Width Modulation (SPWM) and Space Vector Modulation (SVM), is executed through comprehensive simulations. This examination hinges on their capability to curtail EMI across the electromagnetic spectrum. Following assessment of switching techniques, a system level loss distribution analysis is done to map which switches have more concentration of switching losses. Accordingly, a unique gate driver design is proposed for each switch, and improvements in
EMI magnitude and switching losses are noted. In sum, this research endeavours to refine EV systems by orchestrating advanced switching techniques and tailored gate driver designs. By doing so, it aspires to bring down EMI to optimal levels and unlock a future of seamless electric mobility.
Beskrivning
Ämne/nyckelord
Keywords: EMI, NPC, MLI, Gate driver, switching losses, wide-bandgap switches, slew rate control, Space Vector Modulation (SVM)