Modeling of photovoltaic (PV) systems is essential for the designers of solar generation plants to do a yield analysis that accurately predicts the expected power output under changing environmental conditions. This paper presents a comparative analysis of PV module modeling methods based on the single-diode model with series and shunt resistances. Parameter estimation techniques within a modeling method are used to estimate the five unknown parameters in the single diode model. Two sets of estimated parameters were used to plot the I–V characteristics of two PV modules, i.e., SQ80 and KC200GT, for the different sets of modeling equations, which are classified into models 1 to 5 in this study. Each model is based on the different combinations of diode saturation current and photogenerated current plotted under varying irradiance and temperature. Modeling was done using MATLAB/Simulink software, and the results from each model were first verified for correctness against the results produced by their respective authors. Then, a comparison was made among the different models (models 1 to 5) with respect to experimentally measured and datasheet I–V curves. The resultant plots were used to draw conclusions on which combination of parameter estimation technique and modeling method best emulates the manufacturer specified characteristics.

Comparative Analysis of Different Single-Diode PV Modeling Methods

Wide bandgap (WBG) device-based power electronics converters are more efficient and lightweight than silicon-based converters. WBG devices are an enabling technology for many motor drive applications and new classes of compact and efficient motors. This paper reviews the potential applications and advances enabled by WBG devices in ac motor drives. Industrial motor drive products using WBG devices are reviewed, and the benefits are highlighted. This paper also discusses the technical challenges, converter design considerations, and design tradeoffs in realizing the full potential of WBG devices in motor drives. There is a tradeoff between high switching frequency and other issues such as high dv/dt and electromagnetic interference. The problems of high common mode currents and bearing and insulation damage, which are caused by high dv/dt , and the reliability of WBG devices are discussed.

Wide Bandgap Devices in AC Electric Drives: Opportunities and Challenges

Third Generation Photovoltaics Advanced Solar Energy Conversion

The characterization of soft-switching losses (SSL) of modern high-voltage SiC mosfet s is a difficult but necessary task in order to provide a sound basis for the accurate modeling of converter systems, such as medium-voltage-connected solid-state transformers, where soft-switching techniques are employed to achieve an improved converter efficiency. Switching losses (SL), in general, are typically measured with the well-known double pulse method. In the case of SSL measurements, however, this method is very sensitive to the limited accuracy of the measurement of the current and voltage transients, and thus is unsuitable for the characterization of fast-switching high-voltage mosfet s. This paper presents an accurate and reliable calorimetric method for the determination of SSL using the example of 10-kV SiC mosfet modules. Measured SSL curves are presented for different dc-link voltages and switched currents. Furthermore, a deeper analysis concerning the origin of SSL is performed. With the proposed measurement method, it can be experimentally proven that the largest share of the SSL arises from charging and discharging the output capacitance of the mosfet module and especially of the antiparallel junction barrier Schottky diode.

Accurate Transient Calorimetric Measurement of Soft-Switching Losses of 10-kV SiC mosfets and Diodes

Driving solutions for power semiconductor devices are experiencing new challenges since the emerging wide bandgap power devices, such as silicon carbide (SiC), with superior performance become commercially available. Generally, high switching speed is desired due to the lower switching loss, yet high $dv/dt$ and $di/dt$ can result in elevated electromagnetic interference (EMI) emission, false-triggering, and other detrimental effects during switching transients. Active gate drivers (AGDs) have been proposed to balance the switching losses and the switching speed of each switching transient. The review of the in-existence AGD methodologies for SiC devices has not been reported yet. This review starts with the essence of the slew rate control and its significance. Then, a comprehensive review categorizing the state-of-the-art AGD methodologies is presented. It is followed by a summary of the AGDs control and timing strategies. In this work, using AGD to reduce the EMI noise of a 10-kV SiC MOSFET system is reported. This work also highlights other capabilities of AGDs, including reliability enhancement of power devices and rebalancing the mismatched electrical parameters of parallel- and series-connected devices. These application scenarios of AGDs are validated via simulation and experimental results.

A Review of Switching Slew Rate Control for Silicon Carbide Devices Using Active Gate Drivers

Medium-voltage (MV) silicon carbide (SiC) devices have opened up new areas of applications which were previously dominated by silicon-based IGBTs From the perspective of a power converter design, the development of MV SiC devices eliminates the need for series connected architectures, control of multilevel converter topologies which are necessary for MV applications, and the inherent reliability issues associated with it However, when SiC devices are used in these applications, they are exposed to a high peak stress (5–10 kV) and a very high $dv/dt$ (10–100 kV/ $\mu$ s) Using these devices calls for a gate driver with a dc–dc isolation stage that has ultralow coupling capacitance in addition to be able to withstand the high isolation voltage This paper presents a new MV gate driver design to address these issues while maintaining a minimal footprint for the gate driver An MV isolation transformer is designed with a low interwinding capacitance, while maintaining the clearance, creepage, as well as insulation standards A dc isolation test has been performed to validate the integrity of the insulating material The key features include low input common mode current, and a short-circuit protection scheme specifically designed for 10 kV SiC mosfet s The performance of the gate driver is evaluated using double pulse tests and continuous tests Experimental results validate the advantages of the gate driver and its application for MV SiC devices exhibiting very high $dv/dt$  The proposed gate driver concept is aimed at providing an efficient and reliable method to drive MV SiC devices

Design Considerations and Development of an Innovative Gate Driver for Medium-Voltage Power Devices With High $dv/dt$

This paper presents a comparative study between various models of Photo-Voltaic (PV) array which have been formulated exclusively using the data sheet parameters. The models used for comparative study in this paper includes single diode model, the two diode model, the simplified single diode model and the improved single diode model. PV systems are generally integrated with specific control algorithms in order to extract the maximum possible power. Hence it is highly imperative that the Maximum Power Point (MPP) is achieved effectively and thus we need to design a model from which the MPPT algorithm can be realized in an efficient way. Also other parameters should be taken into account for finding the best model for the use in simulator. In this paper, comparisons have been made on basis of the MPP tracking, the RMSD from the experimental data. Further, the resemblance of the P-V and I-V curves as obtained on the basis of experimental data has also been included in this study. On the basis of all these, the best model that can be used for simulation purposes has been selected. It is envisaged that the work can be very useful for professionals who require simple and accurate PV simulators for their design. All the systems here are modeled and simulated in MATLAB/Simulink environment.

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Comparative analysis of mathematical modeling of Photo-Voltaic (PV) array

For high power medium voltage (MV) grid connected applications LCL filter proves to be an attractive solution to filter out the current harmonics when compared to $L$ or LC filters. The inductance requirement reduces drastically to meet the same Total Harmonic Distortion (THD) standards for grid connections for LC L filters compared to $L$ filter which makes the system dynamics much faster. The increasing use of Silicon Carbide (SiC) based power devices for MV applications has made the effects of the parasitic elements in the filter more prominent, due to the high dv / dt experienced by the passive filter elements during device switching transients. This paper addresses the issues associated with the high dv / dt experienced by the LC L filters for SiC-based MV applications. In order to study these effects, the parasitic elements of the inductor are modeled and analyzed. A suitable solution is proposed to improve the overall system performance. The effect of high dv / dt on the filter and the effectiveness of the proposed solution are validated using simulation. Experimental data is also provided to validate the proposed concept.

Practical Design Considerations for MV LCL Filter Under High dv/dt Conditions Considering the Effects of Parasitic Elements

A conventional transformer can withstand multiple electrical, mechanical and thermal faults which enables it to have a long lifetime. However, its inability to control the power flow through it has led researchers to look for alternate options such as the solid-state transformers. With the Silicon Carbide (SiC) semiconductor devices, it is now possible to go to high switching frequencies in medium voltage applications, which helps in reducing the overall size and weight of the transformer. The advent of medium voltage (MV) SiC devices has enabled the use of simple two-level and three-level topologies for medium voltage power transfer. This paper discusses a basic power topology for a medium voltage mobile utilities support equipment based solid state transformer (MUSE-SST) with the new 10 kV SiC MOS-FETs. A design of the MUSE-SST is presented followed by some of the practical considerations that needs to be taken, including gate driver design and heat sink configurations. Simulation results for a 100 kW, MV MUSE SST system is presented. Experimental results are provided validating the operation of these 10 kV devices in double pulse tests, buck and boost operation. This research helps in providing an overview regarding the usage of the 10 kV SiC devices in grid-interconnection and also discusses various challenges that comes along with it.

Design of a Medium Voltage Mobile Utilities Support Equipment based Solid State Transformer (MUSE-SST) with 10 kV SiC MOSFETs for Grid Interconnection

Extensive research in wide-bandgap material technology such as silicon carbide (SiC) has led to the development of medium-voltage (MV) power semiconductor devices with blocking voltages of 3.3 to 15 kV. When these devices are used in various applications, they are exposed to a high peak voltage stress and a very high $dv/dt$ (50–100 V/ns). These impose stringent requirements on the gate driving stage for these devices in terms of featuring a high isolation voltage capability along with a high $dv/dt$ ruggedness, which makes it necessary to have an ultralow coupling capacitance between primary and secondary sides of the gate drivers. One of the key issues in achieving this MV insulation pertains to the necessary clearance and creepage requirements, as defined in IEC 61800-5-1 standards. While the successful operation of these gate drivers is demonstrated in MV converter applications such as solid-state transformers, and MV grid-connected inverters, substantial research needs to be carried out to improve the gate drivers’ performance and provide a plug-and-play solution. This article aims to comprehensively review these gate drivers and consolidate various required design features concerning their galvanic isolation stage, based on normal and short-circuit operation of MV high-power converter systems. Different device short-circuit protection schemes for these gate drivers are explored in detail. Additional applications and functionalities of the gate drivers, including gate drivers used in the series-connection of MV devices and intelligent gate drivers, are also provided in brief. Based on prior research, this review aims to provide design choices and guidelines for the gate drivers, accelerating the growth and deployment of MV SiC devices for field applications.

Anup Anurag

Papers

Design Considerations and Development of an Innovative Gate Driver for Medium-Voltage Power Devices With High $dv/dt$

Comparative analysis of mathematical modeling of Photo-Voltaic (PV) array

Practical Design Considerations for MV LCL Filter Under High dv/dt Conditions Considering the Effects of Parasitic Elements

Design of a Medium Voltage Mobile Utilities Support Equipment based Solid State Transformer (MUSE-SST) with 10 kV SiC MOSFETs for Grid Interconnection

Gate Drivers for Medium-Voltage SiC Devices