Niloofar Rashidi Mehrabadi

Busbar design for SiC-based H-bridge PEBB using 1.7 kV, 400 a SiC MOSFETs operating at 100 kHz

This paper presents a systematic study of the busbar design and optimization for SiC-based H-bridge power electronics building block (PEBB) used in high-frequency and high-power applications. Step-by-step guidelines are presented in which the design considerations and analysis are given. This paper presents a double-sided busbar concept to create a compact PEBB design with improved thermal and switching performance, which result from having double-side cooling and symmetric minimized current commutation loop inductances, respectively. The proposed concept is verified experimentally by evaluating the high-speed switching performance of the PEBB up to 400 A.

Sensitivity analysis of a modular multilevel converter

This paper employs the sensitivity analysis technique to develop a modular multilevel converter (MMC) model that provides a guide for how the design should be carried out. There are several design criteria that it is necessary to take into account when designing a converter. In the case of the MMC, these criteria are a function of many variables. The sensitivity analyses guide the modeling effort, and minimize the number of variables required for inclusion in the model in order to predict system behavior. These techniques are discussed in this paper, and are used to provide rankings of different parameters based on their contribution to predicting the peak voltage across the semiconductor device in an MMC.

Study of the predictive capability of modular multilevel converter simulation models under parametric and model form uncertainty

The deviation of real system behavior from the predictions made from modeling and simulation is inevitable due to variations in different model input parameters as well as inaccurate modeling. The potential sources of uncertainty in modular multilevel converters (MMCs) is significant in medium- and high-voltage applications where each arm consists of several power electronics building blocks (PEBBs) connected in series. Therefore, assessing the predictive proficiency of the model, in the presence of various uncertainties, is critical in gaining confidence in modeling and simulation results. This paper investigates the predictive capability of MMC simulation models when adding more PEBBs. The relationship between the total uncertainty in modeling and simulation, and the number of PEBBs in each arm is presented for different model outputs. The results reveal an interesting feature of MMC — despite the fact that the number of potential sources of uncertainty increases by adding more PEBBs in each arm, the total uncertainty in the prediction of a system response quantity remains the same or decreases, depending on the selected model output response.

Design of a SiC-based modular multilevel converter for medium voltage DC distriution system

The Modular Multilevel Converter (MMC) is a promising converter choice for Medium Voltage DC (MVDC) distribution systems, where SiC devices can be readily adopted taking full advantage of this semiconductors properties. Specifically, 1.7 kV SiC MOSFETs are used to build 1kV modules operating at 100 kHz, thus eliminating the need to use multiple modules to generate a high equivalent switching frequency. Furthermore, a full-bridge configuration is used to take advantage of the additional control and energy storage capabilities that it offers when compared to conventional half-bridge modules. The full in-depth design, controls, and testing of the MMC prototype for MVDC distribution systems is presented in this paper, including among others: component selection, control algorithms, control hardware implementation, precharge and discharge circuits, and protection scheme. Experimental results are presented to demonstrate the proposed SiC-based converter.

Predicting the behavior of a high switching frequency SiC-based modular power converter based on low-power validation experiments

This paper predicts the behavior of a high-switching frequency SiC-based modular power converter based on low-power validation experiments. Switching model of the modular power converter is developed and low-power validation experimental results are provided. Different sources of uncertainties causing the deviation of the modeling and simulation results from the real system behavior are identified, characterized, and quantified via verification and validation analysis using the switching model and low-power validation experiments. A regression-based model is then used to extrapolate the estimated model form uncertainty (MFU) to the full-power condition where there is no experimental data available.

Model-based design of a modular multilevel converter with minimized design margins

A discrepancy between simulation and experimental results is inevitable due to their different sources of uncertainty, which are not usually incorporated at an early design stage. Therefore, design margins are used for design variables in order to generate reliable modeling and simulation-based designs. These margins are generally estimated using heuristic safety factors. In this paper, a design margin calculation procedure is proposed to minimize the allocated margin of the selected design specification when designing a converter in order to better utilize the converters components. This procedure is based on probabilistic modeling and simulation, which take into account different sources of uncertainties.

Multi-objective design and optimization of a vienna rectifier with parametric uncertainty quantification

The performance of power electronic converters is sensitive to main design variables such as topology, control algorithm, and modulation scheme as well as details such as manufacturing variability. In this paper, sensitivity index is introduced as an indicator of design quality to measure converter robustness in the presence of manufacturing uncertainty. This paper presents the design and optimization of a Vienna rectifier that converts variable frequency 115 V AC voltage into 340 V DC voltage to illustrate the multi-objective optimization with parametric uncertainty quantification. The primary design target is to maximize converter efficiency and robustness within given size limitations and operation requirements.

Modeling and design of the modular multilevel converter with parametric and model-form uncertainty quantification

This paper presents a design methodology with uncertainty quantification to estimate the required margin for two main design variables in a modular multilevel converter (MMC). In this methodology, the minimum required design margins are calculated by quantifying all sources of uncertainty in the modeling and simulation of MMCs. To this end, an enhanced modeling framework is presented to take into account the parametric uncertainty (PU) that results from manufacturing variability, and model-form uncertainty (MFU) that results from inherent inaccuracies of the models used in the design process. In this paper, sensitivity analysis (SA) is used to guide the modeling effort and minimize the number of uncertain parameters required for inclusion in uncertainty quantification. Besides, a simplified testbed for model validation of the MMC is developed. This testbed is used for conducting low-power validation experiments and Monte-Carlo simulations to estimate PU and MFU, respectively.

Power Electronics Building Block (PEBB) design based on 1.7 kV SiC MOSFET modules

This paper presents the design of a Power Electronics Building Block (PEBB) based on 1.7 kV SiC MOSFET power modules. The PEBB is an H-bridge converter module that can be cascaded to construct multilevel converters. Novel designs including gate driver with Rogowski shortcircuit protection, powerful distributed controller, isolated A/D sensor with high common-mode noise rejection, double-side cooling mechanical layout have been achieved. The paper begin with the evolution of PEBB architectures and the specifications of the designed PEBB. It then presents detailed design considerations and solutions of all the critical components. Finally, experimental results demonstrate the excellent performance of the individual components and the PEBB as a unity in various operation modes.

DC fault current control of modular multilevel converter with SiC-based Power Electronics Building Blocks

The Medium Voltage dc (MVDC) distribution is actively being sought as the eventual structure for the next-generation shipboard electrical power systems and the Modular Multilevel Converter (MMC) has become a preferred choice for MVDC systems. However, the fault response is a big challenge for both the shipboard MVDC system and the MMC. A fault current control is proposed to work with MMCs composed of full-bridge Power Electronics Building Blocks (PEBBs). The converter is able to fast clear the fault current when a dc shortcircuit fault happens and easily restore the service after the fault is isolated. The fault response is verified by both simulation results and experimental results from a three-phase SiC PEBBs based MMC prototype.