Investigation of Switching Oscillations for Silicon Carbide MOSFETs in Three-Level Active Neutral-Point-Clamped Inverters

Abstract

This paper investigates the multi-frequency switching oscillations of silicon carbide (SiC) MOSFETs in three-level active neutral-point-clamped (3L-ANPC) inverters under three typical commutation modes (i.e., the full mode, outer mode, and inner mode). Multiple switching-oscillation components with various frequencies are identified theoretically for both the fullmode and outer-mode commutations, due to their switching-loop diversities. Oppositely, the inner mode exhibits a single oscillation component as only one switching loop is involved. Three types of double-pulse tests (DPTs) are conducted on a 3L-ANPC inverter demonstrator with SiC MOSFETs, and the switching-oscillation components are extracted accordingly, which match well with the theoretical derivations. Moreover, other switching characteristics closely related, i.e., the oscillation peaks, current overshoots, capacitive charges, and switching energies, are studied and benchmarked according to the DPT results. It is concluded that the full-mode and outer-mode commutations share similarities in terms of switching oscillations, current overshoots, capacitive charges, and turn-on energies. The theoretical findings from this work provide a comprehensive knowledge of the multi-frequency oscillation mechanisms associated with fast-switched 3L-ANPC inverters. Accordingly, the critical parasitic-components are identified, and specific design considerations are proposed to achieve switching-performance improvements.

Model Predictive Control Strategy Based on Loss Equalization for Three-Level ANPC Inverters

“…Literature [17] combines the two methods to turn a single zero-level clamp circuit into two clamp circuits conducting at the same time, which reduces the conduction loss and increases the efficiency. Literature [18] regulates the frequency cycle, changing the duration ratio of mode one and mode 2 in each frequency cycle to realize the balanced adjustment of switching tube losses, but the ratio selection lacks a theoretical basis, and frequent switching between different modes will produce excessive switching losses, affecting the system efficiency [19]. Literature [16,20,21] used a model prediction method of multi-objective optimization for loss equalization control by setting the value function loss minimization but did not classify and make full use of the ANPC inverter redundancy zero level in a manner, whereas literature [20,21] used only manner two and its variants.…”

Modulation Strategy for Suppressing Peak Voltage Spikes of SiC-MOSFETs During ANPC Commutation

“…Chen. M established the model of the ANPC single-phase bridge arm with parasitic parameters and analyzed the reason for the switching oscillation of SiC-MOSFETs [21], which provided the theoretical basis for the research of ANPC based on SiC-MOSFETs. However, the suppression strategy of the peak voltage of SiC-MOSFETs has not been considered too much.…”

All-SiC ANPC Submodule for an Advanced 1.5 kV EV Charging System under Various Modulation Methods

“…Moreover, while systems comprised of ANPC submodules have been shown in the past, they are connected with other power semiconductor device types, such as IGBTs [26,27] or IGCT [28]. There are no publications regarding SiC MOSFETbased systems rated at MV level, whereas for such an application, the impact of parasitic inductances due to high dv/dt rates and a high switching speed is much more severe, and thus also more critical during the design process [29].…”