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Harmonic Analysis and Controller Design of 15 kV SiC IGBT-Based Medium-Voltage Grid-Connected Three-Phase Three-Level NPC Converter
Date Issued
01-05-2017
Author(s)
Madhusoodhanan, Sachin
Mainali, Krishna
Tripathi, Awneesh
Patel, Dhaval
Kadavelugu, Arun
Bhattacharya, Subhashish
Indian Institute of Technology, Madras
Abstract
Cascaded converters are generally used for medium-voltage (MV) grid-connected applications due to the limitation in the voltage rating of available silicon (Si) power devices. These converters find application in active power filters, STATCOM or as the active front end converters for solid state transformers at the distribution voltage levels. The high voltage wide bandgap semiconductor devices have enabled the grid connected operation of noncascaded converters. This results in high power density, less number of switching devices, and high efficiency for three-phase MV grid interface. This also results in control simplicity without the need for complex dc bus balancing algorithms otherwise needed for cascaded converters. However, such noncascaded, grid-connected converters introduce challenges in maintaining power quality at low currents. This paper investigates the harmonic performance and current distortion of the grid-connected, three-level neutral point clamped converter using 15 kV silicon carbide Insulated Gate Bipolar Transistor (IGBTs). A suitable control scheme for stable harmonic compensation is proposed. The challenges and control performance are explained through frequency domain analysis, simulations, and experimental validation on a developed prototype of the three-phase converter up to 4.16 kV, three-phase MV grid-connected operation.
Volume
32