Modular Power Conversion Cabinet for Future Warships Anna V Brinck- Graduate student, University of Wisconsin-Milwaukee Robert M Cuzner- Assistant Professor, University of Wisconsin-Milwaukee

Introduction Next generation Navy Ships will have high power electric weapons and sensors and are trending towards medium voltage DC (MVDC) power systems Novel power conversion solutions are required to accommodate these diverse power requirements and see to the challenges presented in power conversion such as reliability, high power pulsed loads, and safety. Power conversion devices, in addition to being safe and reliable, need to stay within volume, mass and cost constraints.

Ship Power System Overview 4 to 6 zone layout Zones divided into left and right (Port and Starboard) Each zone has 3 to 4 tiers of power conversion, each requiring its own power conversion cabinet design Redundancy of cabinets in case of damage to part of the ship Whole ship zonal layout Converter cabinets in half zone

Modular Power Conversion Cabinet Specifications • The Integrated Power Node Center (IPNC) is a power conversion cabinet with two inputs and 6 outputs • Two possible DC inputs, one from within the same ship zone and one that can be routed from an adjacent ship zone in case of an emergency • Six outputs for specific ship loads •Another useful feature of the PCM1A is that it has energy storage capability for ~1sec, enabling the support of uninterruptable (UI) loads.

Determining Least Replacable Units It is necessary to determine the Least Replacable Units (LRU) to minimize cost Choice of LRU determines how sailors will do repairs on the fly IPNC contains AC to DC, DC to DC, and DC to AC converters, all of which have duplicate components Converter topologies and likely LRU choices

EMI Filtering • Filters for the output of converters must be designed to mitigate conducted Electromagnetic Interference (EMI.) • Differential Mode (DM) and Common Mode (CM) EMI must be filtered • Line Impedance Stabilization Network (LISN) is modeled at output of converter to measure EMI

Creating a Metamodel A metamodel is an equation or algorithm that will output the size and weight of the cabinet given the materials and required power specifications Size and weight is especially important in ship applications, because space is limited and weight adds to fuel cost Size and weight can not be easily determined directly from the physics of the cabinet Our IPNC metamodel is being created using an iterative process that requires testing many different possible topologies of the converter

Construction and Testing with Wide Bandgap Semiconductor material An input converter for the IPNC is being constructed and operation with WBG semiconductor material is being tested in our lab Benefits of SiC MOSFET/diode switching devices are: -Can operate at higher voltage, -Higher temperature, and -Higher switching frequency • The end result is higher power density and efficiency

Summary Given the Navy’s specifications for the IPNC, we are designing an optimal power conversion cabinet by - • Making the most cost effective choice of Least Replacable Units • Designing filters to mitigate conducted EMI • Testing WBG semiconductor devices to reduce overall size and weight of the cabinet • Creating a metamodel to quickly and easily determine feasibility of future designs