Reducing circulating currents in interleaved converter legs under selective harmonic elimination pulse-width modulation

Abstract

Abstract-Interleaving of voltage source converter legs enables higher output currents per phase, effectively increasing the power rating without increasing semiconductor ratings. Different switching patterns between the converter legs increase the number of Thevenin output voltage levels and, hence, the quality of the waveform but also generate circulating currents within one phase. This paper proposes a controller for interleaved converter legs under selective harmonic elimination pulse-width modulation (SHE-PWM) aimed at reducing the circulating current within the legs of each phase. The controller is used in combination with optimally selected SHE-PWM patterns to minimise the peak value of the circulating current. The proposed controller is applied in two interleaved three-level active neutral-pointclamped converters and simulation results demonstrate their performance.

Interleaved Operation of Three-Level Neutral Point Clamped Converter Legs and Reduction of Circulating Currents Under SHE-PWM

“…9(b). The current sharing between the two interleaved legs of the same phase (i a1 and i a2 ) are also significantly different as it was demonstrated in [9]. The ZSCC (also shown in Fig.…”

“…The results are equally applicable to neutral-point clamped (NPC) and active NPC (ANPC) converters. The current article extends the preliminary work that was presented in [9] by providing the detailed evaluation of SHE-PWM patterns and a comprehensive set of experimental results for interleaved three-level converters.…”

Single-Carrier Phase-Disposition PWM Techniques for Multiple Interleaved Voltage-Source Converter Legs

“…The use of a centralized controller with common dc-voltage control and one or multiple current controllers is more common in high-power converters and applications with a common dc-voltage source, providing a better alternative to the parallel connection of semiconductors. Additionally, the larger amount of information available to the controllers provides greater flexibility and direct control of circulating currents that might be present [3]. A common controller further enables harmonic cancellation between interleaved converters by synchronizing their modulation.…”

“…However, it is well established that the harmonic performance of both techniques is not optimal [23]. The application of selective harmonic elimination PWM (SHE-PWM) for interleaved converters was discussed in [3] the technique limited to low switching frequency operation.…”

Modulação Descontínua com Portadora para Inversores com Pernas em Paralelo

“…Em [4], é proposta uma modulação híbrida PWM-SHE (PWM-eliminação seletiva de harmônicas) a fim de reduzir as correntes circulantes nas pernas de cada fase, por meio da escolha adequada dos ângulos para a eliminação de harmônicas. Assim, o controlador é decomposto em duas partes: a primeira gera os padrões PWM-SHE, e a segunda seleciona os estados de condução para controlar as correntes circulantes.…”