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Power Conditioning Surge Module for Standalone Power and Tactical Microgrids

Description:

TECHNOLOGY AREA(S): Materials 

OBJECTIVE: Design and develop a Power Conditioning Surge Module (PCSM) capable of enabling of military power systems to better handle non-linear loads and power surges in excess of 125% rated power for 3 to 5 seconds. Military generator sets are typically oversized to handle surge loads and inrush currents which can exceed 200-300% of the generator’s rated power. Since over-sizing a generator set is both wasteful in terms of fuel consumption, and detrimental to the generator’s reliability and lifespan, the goal is to enable end users to “right size” their generator sets in accordance with the average load power—not peak power requirements. 

DESCRIPTION: The Army is in need of a power dense surge module that can be used with any military generator set and enable it to handle non-linear loads and power surges greater than or equal to 125%. A load is considered non-linear if its impedance changes with the applied voltage. The changing impedance means that the current drawn by the non-linear load will not be sinusoidal even when it is connected to a sinusoidal voltage. These non-sinusoidal currents contain harmonic currents that interact with the impedance of the power distribution system to create voltage distortion that can affect both the distribution system equipment and the loads connected to it. Examples of harmonic producing loads are Switch-Mode Power Supplies (SMPS), AC or DC motor drives, inverters, DC converters, etc. Higher frequency harmonic currents flowing through power systems can cause communication errors, overheating and hardware damage such as overheating of electrical distribution equipment, cables, and transformers. High voltages and circulating currents caused by harmonic resonance can also lead to equipment malfunctions, increased internal energy losses in connected equipment, component failure, shortened life span, false tripping of branch circuit breakers, etc. With regard to momentary power surges that exceed 125%, this will typically cause the generator set to exhibit excessive voltage dip (i.e. brownout condition) which is also likely to result in equipment malfunctions and/or failures. The Army seeks a PCSM that is designed to enhance performance of its current and emerging fleets of power generation equipment. The goal is to achieve a solution weighing no more than 15% (objective) to 20% (threshold) of the target generator set size, to improve overall power quality, reduce the statistical likelihood of a brownout, and allow for the use of a smaller sized genset. Any control techniques used in the solution set must not rely on any communications with the voltage regulator or sinewave inverter used within the host generator set, and must not induce any voltage regulation or engine speed instabilities of its own across all foreseeable tactical operating conditions. The final deliverable PCSM enclosure must feature both cam-lock and split-lug terminals for both the input and output, and must be packaged to withstand the same environmental conditions (i.e. any possible relative humidity, salt spray, ambient temperature from -32 to 60C, 1219m altitude @ 35C) as the target power system. 

PHASE I: Identify the types of loads currently used in the battlefield and characterize them in terms of harmonic content (Total Harmonic Distortion, THD), crest factor, power factor (inductive & capacitive), and surge current amplitude and duration. Using these results, identify power electronic topologies, energy storage devices, and control algorithms that can be employed to supply the non-sinusoidal harmonic current as well as transient power surges automatically. 

PHASE II: Develop the Power Conditioning Surge Module. Validate its operation and demonstrate its ability to enhance the power quality and double the peak power (for 3-5 seconds) of a 15 kW TQG or AMMPS generator set. Demonstrate that the PCSM can improve power quality and enable right sizing of power equipment in a tactical setting. 

PHASE III: Advance Power Conditioning Surge Module (PCSM) technology to TRL Level 7/8 for transition to PM-E2S2 for projected acquisitions, and develop a complete family of different size PCSMs to cover the full range of medium to large power applications from 3 kW to 200 kW. Implement the PCSM on tactical microgrids to address surge and peak shaving requirements and potential residential, commercial and recreational applications. 

REFERENCES: 

1: http://asc.army.mil/web/portfolio-item/cs-css-advanced-medium-mobile-power-source-ammps/

2:  MIL-STD-1332B: Power Quality

3:  MIL-STD-633G

KEYWORDS: TQG, AMMPS, Generator, Nonlinear Loads, Inrush Current, Surge Power, Power Electronics, Energy Storage 

CONTACT(S): 

Mr. Edmund Nawrocki 

(443) 395-4799 

edmund.a.nawrocki2.civ@mail.mil 

Selma Matthews 

(703) 704-3377 

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