Frank Jakob John Mueller

An Efficient Partial Power Processing DC/DC Converter for Distributed PV Architectures

In this paper, a dc/dc power converter for distributed photovoltaic (PV) plant architectures is presented. The proposed converter has the advantages of simplicity, high efficiency, and low cost. High efficiency is achieved by having a portion of the input PV power directly fed forward to the output without being processed by the converter. The operation of this converter allows for a simplified maximum power point tracker design using fewer measurements. The stability analysis of the distributed PV system comprised of the proposed dc/dc converters confirms the stable operation even with a large number of deployed converters. The experimental results show a composite weighted efficiency of 98.22% with very high maximum power point tracking efficiency.

A High-Power-Density DC–DC Converter for Distributed PV Architectures

In order to maximize the solar energy harvesting capabilities, power converters for photovoltaic (PV) systems have to be designed for high efficiency, accurate maximum power point tracking (MPPT) and voltage/current performance. When many converters are used in distributed PV systems, power density also becomes an important factor since it allows for simpler system integration. In this paper, a high power density string level MPPT DC-DC converter suitable for distributed medium to large scale PV installations is presented. A simple partial power processing topology implemented exclusively with silicon carbide devices provides high efficiency and high power density. A 3.5kW, 100 kHz converter is designed and tested to verify the proposed methods.

Overview of 1.2kV – 2.2kV SiC MOSFETs targeted for industrial power conversion applications

This paper presents the latest 1.2kV-2.2kV SiC MOSFETs designed to maximize SiC device benefits for high-power, medium voltage power conversion applications. 1.2kV, 1.7kV and 2.2kV devices with die size of 4.5mm × 4.5mm were fabricated, exhibiting room temperature on-resistances of 34mOhm, 39mOhm and 41mOhm, respectively. The ability to safely withstand single-pulse avalanche energies of over 17J/cm2 is demonstrated. Next, the 1.7kV SiC MOSFETs were used to fabricate half-bridge power modules. The module typical onresistance was 7mOhm at Tj=25°C and 11mOhm at 150°C. The module exhibits 9mJ turn-on and 14mJ turn-off losses at Vds=900V, Id=400A. Validation of GEs SiC MOSFET performance advantages was done through continuous buck-boost operation with three 1.7kV modules per phase leg exhibiting 99.4% efficiency. Device ruggedness and tolerance to terrestrial cosmic radiation was evaluated. Experimental results show that higher voltage devices (2.2kV and 3.3kV) are more susceptible to cosmic radiation, requiring up to 45% derating in order to achieve module failure rate of 100 FIT, while 1.2kV MOSFETs require only 25% derating to deliver similar FIT rate. Finally, the feasibility of medium voltage power conversion based on series connected 1.2kV SiC MOSFETs with body diode is demonstrated.

High Performance Silicon Carbide Power Block for Industry Applications

Silicone carbide (SiC) power devices have been optimized in performance over the past decade. However, wide industry adoption of SiC technology still faces challenges from system design perspective. This paper demonstrates an integrated air-cooled three-phase SiC power block for industry applications. The key design aspects, such as high performance gate driver, low parasitic layout, optimized thermal management, as well as flexible control platform are addressed. Experimental results are provided to demonstrate the superior performance of the design.

High performance SiC power block for industry applications

SiC power devices have been optimized in performance over the past decade. However, wide industry adoption of SiC technology still faces challenges from system design perspective. This paper demonstrates an integrated air-cooled three phase SiC power block for industrial applications comprising high performance gate driver, low parasitic layout, optimized thermal management, as well as a flexible control platform. Experimental results are provided to demonstrate the superior performance of the design.

A high efficiency DC-DC converter topology suitable for distributed large commercial and utility scale PV systems

In this paper a DC-DC power converter for distributed photovoltaic plant architectures is presented. The proposed converter has the advantages of simplicity, high efficiency, and low cost. High efficiency is achieved by having a portion of the input PV power directly fed forward to the output without being processed by the converter. The operation of this converter also allows for a simplified maximum power point tracker design using fewer measurements.