AT Power Distribution System Guide Rev 1 (1) · Power Distribution System – System and...

AT COMMUNICATION

POWER DISTRIBUTION SYSTEM TECHNICAL GUIDE

AT Communication Power Distribution System – System and Configuration Guide

Systems and Configuration Guide ATSCG-PDS of 20

CONTENTS

1. INTRODUCTION AND OVERVIEW .............................................................................................................. 4

1.1 INTRODUCTION ......................................................................................................................................... 4 1.2 SYSTEM OVERVIEW .................................................................................................................................... 4 1.3 PDS FEATURES AND CAPABILITY .................................................................................................................... 4 1.4 SYSTEM CONFIGURATIONS ........................................................................................................................... 5

2. MAIN MODULES ......................................................................................................................................... 6

2.1 FILTER UNIT ............................................................................................................................................. 6 2.1.1 Filter Unit Function ........................................................................................................................ 6

2.2 POWER SPLITTER UNIT ................................................................................................................................ 7 2.2.1 Power Splitter Function .................................................................................................................. 7

2.3 LOW POWER UNIT ..................................................................................................................................... 7 2.3.1 Lower Power Unit Function ............................................................................................................ 7

2.4 HIGH POWER UNIT .................................................................................................................................... 8 2.4.1 High Power Unit Function .............................................................................................................. 8

3. CONFIGURATIONS ...................................................................................................................................... 9

3.1 CONFIGURATION 1 FULL SYSTEM WITH BOTH BATTERY MANAGEMENT AND METERING .............................................. 9 3.2 CONFIGURATION 2 FULL SYSTEM WITH BATTERY MANAGEMENT WITHOUT METERING.............................................. 10 3.3 CONFIGURATION 3 FULL SYSTEM WITHOUT BATTERY MANAGEMENT OR METERING ................................................. 11 3.4 CONFIGURATION 4 HIGH POWER ONLY WITH METERING AND BATTERY MANAGEMENT............................................. 12 3.5 CONFIGURATION 5 HIGH POWER ONLY WITHOUT METERING OR BATTERY MANAGEMENT ......................................... 13 3.6 CONFIGURATION 6 LOW POWER ONLY WITH METERING AND BATTERY MANAGEMENT ............................................. 14 3.7 CONFIGURATION 7 LOW POWER ONLY WITHOUT BATTERY MANAGEMENT OR METERING .......................................... 15

.................................................................................................................................................................... 16

4. SPECIFICATIONS ....................................................................................................................................... 17

4.1 FILTER UNIT ........................................................................................................................................... 17 4.2 POWER SPLITTER UNIT .............................................................................................................................. 17 4.3 LOWER POWER UNIT ................................................................................................................................ 17 4.4 HIGH POWER UNIT .................................................................................................................................. 18

5. OPTIONAL ENHANCEMENTS ..................................................................................................................... 19

5.1 CHARGING ARCHITECTURE (OPTIONAL) ......................................................................................................... 19 5.2 BATTERY MANAGEMENT (OPTIONAL) ........................................................................................................... 19 5.3 DISPLAY METER (OPTIONAL) ...................................................................................................................... 20

6. FURTHER INFORMATION .......................................................................................................................... 21

6.1 SYSTEM DOCUMENTATION ......................................................................................................................... 21 6.2 INTELLECTUAL PROPERTY ........................................................................................................................... 21



No part of this manual may be copied, transcribed, translated or reproduced in any manner or form whatsoever for commercial purposes, without obtaining prior written permission from;

AT ELECTRONIC AND COMMUNICATION INTERNATIONAL LTD

(C) Copyright of AT Electronic and Communication International Ltd



1. INTRODUCTION AND OVERVIEW

1.1 Introduction

In-vehicle power supplies have not changed much in architecture but the equipment installed has and, now with modern digital systems that can deliver vastly improved information flow becoming standard, it is necessary to address a potential problem. Modern digital systems require stable and coherent power as they are more susceptible to variations such as spikes and interference than their legacy analogue systems.

A solution is required that can deliver a coherent 12 or 24 DC power supply to equipment that is interference free, has maximum availability and resilient enough to supply continuous power in what are often extreme operating conditions. A system is required than can operate with dual or triple battery systems and distribute power in a flexible modular architecture for multiple systems. This will allow crew members to focus on the task at hand rather than worrying about the installed systems.

AT Communication is please to provide the Power Distribution System (PDS) to meet the demand outlined above.

1.2 System Overview

The PDS is configured with into four component modules;

Filter Unit (FU)

Power Splitter Unit (PSU)

High Power Unit (HPU)

Low Power Unit (LPU).

1.3 PDS Features and Capability

PDS can support from 1 to 6 installed equipment systems

3 outputs at high power (35 amps) and 3 outputs at low power (6 amps)

Each output is separately fused

A power filter unit removes spikes and interference

Enclosures are rated to IP 64 for water and particle ingress

Interconnection cables are fitted with durable quick release connectors

Power terminals can be supplied with threaded or quick release connection points



1.4 System Configurations

High and Low Power System with Battery Management and Metering

High and Low Power System with Battery Management without Metering

High and Low Power System without Battery Management or Metering

High Power only with Metering and Battery Management

High Power only without Metering or Battery Management

Low Power only with Metering and Battery Management

Low Power only without Battery Management or Metering



2. MAIN MODULES

2.1 Filter Unit

2.1.1 Filter Unit Function

• Provides filtering for spike and interference suppression

• Main interface between Vehicle Power Supply and PDS

• Provides fusing for complete system

• Standard interconnectivity fitting is threaded but can be fitted with quick release connectors.

The feed-through filter has excellent RFI attenuation up to GHz frequency levels. These filters have been used extensively in power supplies and digital telecom systems and provide attenuation of 28dB @ 10 KHz, 42dB @ 100 KHz, 90dB @ 1 MHz and >100 dB at frequencies up to 1 GHz. A circuit breaker (commonly used in current military platforms) is installed in the filter unit rated at the maximum required current for the system 150 amps.



2.2 Power Splitter Unit

2.2.1 Power Splitter Function

• Splits power to both High and Low Power Units

• Threaded terminals or quick release connectors (Option)

The Splitter unit is used when both High and Low Power Units are required.

2.3 Low Power Unit

2.3.1 Lower Power Unit Function

Provides three power outlets of 6 amps each Each outlet separately fused Connection either threaded or quick release terminals Ruggedised heavy duty connectors as standard



The Low Power Unit is installed when low power systems are installed. The unit is provided with up to three cables for connection between the unit and the installed systems 2.4 High Power Unit

2.4.1 High Power Unit Function

• Provides three outlets of 35 amps each

• Each outlet separately fused

• Connection either threaded or quick release terminals

• Heavy duty ruggedised connectors standard

The High Power Unit is installed when the platform has medium to high power systems requiring stable and interference free power. The unit is provided with up to three cables for connection between the unit and the installed systems,



3. CONFIGURATIONS

3.1 Configuration 1 Full System with both Battery Management and Metering



3.2 Configuration 2 Full System with Battery Management without Metering



3.3 Configuration 3 Full System without Battery Management or Metering



3.4 Configuration 4 High Power only with Metering and Battery Management



3.5 Configuration 5 High Power only without Metering or Battery Management



3.6 Configuration 6 Low Power only with Metering and Battery Management



3.7 Configuration 7 Low Power only without Battery Management or Metering



4. SPECIFICATIONS

4.1 Filter Unit

Weight 3 Kg

Dimensions 225x145x90 mm

Temperature Range -30° C to +70° C

Connectivity Connects to Splitter Unit and Low or High Power Units

Construction Ruggedised die cast enclosure with heavy duty ruggedised connectors and internal shock proofing.

Environmental The enclosure is rain shower proof, resistant to condensation and also is resistant to ingress of small particles. Certified to IP 65 (NEMA 4)

4.2 Power Splitter Unit

Weight 1.1 Kg



Connectivity Connects Filter Unit to both low and high power units

Functionality Distributes power to both low and high power units

Construction Ruggedised die cast enclosure with heavy duty ruggedised connectors and internal shock proofing.

Environmental The box is rain shower proof, resistant to condensation and also is resistant to ingress of small particles. Certified to IP 65 (NEMA 4)

4.3 Lower Power Unit

Weight 1.7 Kg





Connectivity Connects to Splitter Unit or Filter Unit

Functionality Provides three outlets of 6 amps

Construction Ruggedised die cast enclosure ruggedised connectors and internal shock proofing


4.4 High Power Unit

Weight 2.1 Kg



Connectivity Connects to Splitter Unit nor Filter Unit

Functionality Provides three outlets of 35 amps

Construction Ruggedised die cast enclosure ruggedised heavy duty connectors and internal shock proofing




5. OPTIONAL ENHANCEMENTS

5.1 Charging Architecture (Optional)

The most efficient way of maintaining both sets of batteries is to utilise a split charging system and this can be achieved by either using Voltage Sensing Relays (not recommended) or diodes. The common belief with relay systems is that an alternator charges the engine-start battery first and then, at a pre-set voltage, brings the auxiliary battery into parallel via the relay. Unfortunately, when the voltage energises the relay it pulls both batteries into parallel at the same time. In addition, a high electrical load on the auxiliary battery, e.g. from an inverter, can cause the relay to momentarily disengage, so the battery then continues to discharge, or the relay starts to ‘chatter’ as it pulls in and out due to the voltage changes. This is often called ‘buzzing’, which is arcing taking place between the relay contacts, dramatically affecting the life expectancy of the relay. Moreover, this arcing could well impinge on radio reception quality and there is also mounting evidence to suggest possible EMC implications (RFI) between some VSR's and radio transmissions.

Diodes are preferred because; firstly, all battery banks are totally isolated from each other, secondly, the charging process is automatic and thirdly, there is apportioned charging of the batteries which means that all batteries receive a charge commensurate with their needs. The voltage drop across the diode-splitter requires some form of compensation and it is necessary to provide a Battery Management system. In conclusion, solid state devices (diodes) are preferred because of their reliability, they do not generate interference and with suitable battery management will provide a coherent charging regime, even with platforms with multiple batteries and alternators.

5.2 Battery Management (Optional)

The Battery Management System is a sophisticated alternator voltage regulator or charge controller which ensures batteries are 95-100% charged with minimum engine running time. An existing alternator charging system is generally optimised for commercial vehicles; however, for specialized platforms, such as all terrain used by aid agencies, emergency services and military, the battery state of charge only ever reaches 65-70% of its capacity with this system, even with the engine running for long periods. These is exacerbated when, during operations the platforms is at rest but not in idle mode and the installed systems are required to be operational.

The aim of the Battery Management System is to produce the optimum charging voltage to the batteries, not the alternator, compensating for voltage losses. These voltages are cycled below and above the gassing point of the battery(s) to a given programme, also compensating for changes in ambient temperature, thereby achieving fast and safe charging. The battery management system does not forced feed in terms of charging current - the batteries only take whatever charging current they need.

The underlying principle is that batteries should be charged fully, quickly, safely and without damage to batteries and alternator. This is achieved, firstly, by cycling the battery voltages to an established programme ensuring rapid charging without the battery



actually gassing. Voltages can also be set to suit battery types e.g. Gel, Ni-cads etc and, moreover, the charging voltages will automatically compensate for ambient temperature variations around the batteries, an important consideration. The net result is efficient alternator performance, compensation for voltage losses in the system (including that across blocking-diodes), accompanied by considerably reduced engine running time

Battery and alternator life are considerably improved but the main benefit comes from having more available battery capacity at one's disposal, (two to three times as much), without having to install extra batteries and bigger alternators.

5.3 Display Meter (Optional)

The display of both current and voltage in the system is a necessity not only to provide confidence to the Users but also for fault finding. The meter has an LCD unit with associated switches and shunts. Generally, most installations show charging current to the batteries and available current and voltage at the batteries and at the output.

Diode Pack

Battery Management Controller



6. FURTHER INFORMATION

6.1 System Documentation

Documentation will be customised for each system dependant on the exact system configuration. Documentation will include user manual, configuration information, system wiring information, user interface instructions and system testing instructions.

6.2 Intellectual Property

All information contained in this manual is the property of;

AT ELECTRONIC AND COMMUNICATION INTERNATIONAL LTD

The information contained within is subject to change.

No part of this manual may be copied, transcribed, translated or reproduced in any manner or form whatsoever for commercial purposes, without obtaining prior written permission.

AT Power Distribution System Guide Rev 1 (1) · Power Distribution System – System and...

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