Informing the power system performance envelope for pulse load operation

Abstract

Future warship power systems may be subject to pulsed loads manifesting through emergent combat systems such as directed energy weapons, associated sensors and electronic warfare equipment. The integration of combat system loads with the ship’s power system means that performance becomes intrinsically linked to combat effectiveness. Hence, understanding the capability of the power system to service such loads is vital in ensuring the operator’s ability to fight the ship. This paper describes the challenge of pulse load integration from the perspective of the power system design authority. Modelling and simulation has been employed to study the electrical response of a representative power system when subject to a range pulse load characteristics. Subsequently, the effects of pulse loading are reviewed in terms of impact upon the prime mover. It is concluded that whilst electrical supply performance can be maintained within allowable power quality limits as defined by STANAG 1008, the mechanical effects can be to the detriment of engine life, highlighting key recommendations to understand both electrical and mechanical performance envelope in design for integration.

Assessing battery energy storage for integration with hybrid propulsion and high energy weapons

“…NMC is currently used in electric vehicle and commercial shipping battery system applications due to a balance of high specific energy and power as a consequence of high cell voltage (typically 4.1-4.3 V per cell) and low internal resistance, moreover NMC has a relatively high thermal runway temperature (Chemali et al 2016). The battery ESS could benefit the power system by mitigating the reported adverse effects exhibited on QPS and power generation components from pulsating loads (Langston et al 2017, Mills et al 2018. This paper aims to firstly, justify the integration location of the ESS and pulsed load within a candidate power system.…”

“…Analytical thermal efficiency map over battery discharge measured at (a) battery terminals i.e. connection to the LDEW converter and (b) connection to the main switchboard The LDEW parameters of interest in this work are derived fromMills et al (2018), presented in…”

Investigating the Performance Capability of a Lithium-ion Battery System When Powering Future Pulsed Loads

“…Future warships are predicted to employ advanced weapon systems, the power for which will be drawn from the ships electric power system. Key among these advanced systems are high power laser directed energy weapons (LDEWs) characterized by a pulsed power profile [1][2][3][4]. Pulsed power load supply is an important factor driving change in power system design and is considered a primary requirement for the integration of energy storage devices that have fast response dynamics capable of driving pulsed loads for sustained periods [5].…”

“…At present, lower power LDEWs below 100 kW are being tested onboard warship power systems [6]. However, the peak pulse power requirement of LDEW systems is currently expected to be up to 2 MW [1][2][3]7].…”

“…Warships with an Integrated Power System may have large gas turbine generators with sufficient ramp rate capability to power megawatt level laser loads. However, this is not necessarily the case for ships with inherently reduced power generation capacity, such as ships with a hybrid electric and mechanical propulsion system [1]. This is because it is unknown whether smaller generator sets, characteristic of hybrid propulsion systems, can provide the intake of combustion air and fuel flow rates to meet the ramp rate demand of high power LDEW loads.…”