1、_SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising theref
2、rom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions.Copyright 2012 SAE International All rights reserved. No part of this pub
3、lication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-4970
4、(outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/AS5698AEROSPACESTANDARDAS5698 Issued 2012-04 Space Power Standard RATIONALEHistorica
5、lly, space power system requirements have been unique for every platform, vehicle, and contractor. This is a roadblock for re-use of equipment on new designs or development of standard products for space applications. The majority of existing power quality specifications were developed for aircraft
6、systems and generally are based on engine driven alternator power sources for AC and transformer rectifier units for DC. Space power sources include fuel cells, thermal electric generators, rotating and reciprocating electromagnetic machines, photovoltaic, and electrochemical systems. All of these s
7、ources have unique properties that must be considered in the development of a power system. In a similar manner, spacecraft loads are often designed for specific platforms, and must be adapted and modified to meet unique voltage ranges and power quality characteristics for new applications. Designin
8、g equipment to a common power standard allows transportability to new platforms with high confidence of compatibility without extensive requalification. INTRODUCTIONThis standard defines the requirements and characteristics of electrical power for spacecraft. This standard also defines analysis, ver
9、ification, and testing methodologies to be used to ensure that the loads operate when connected to the specified power quality and performance as defined by this standard.SAE AS5698 Page 2 of 34 TABLE OF CONTENTS 1. SCOPE 41.1 Purpose . 42. REFERENCES 42.1 Applicable Documents 42.1.1 U.S. Government
10、 Publications 42.2 Abbreviations and Definitions . 42.2.1 Abbreviations 42.2.2 Definitions . 53. GENERAL REQUIREMENTS . 73.1 Electrical Power Characteristics . 73.1.1 System Characteristics . 83.1.2 Normal Operation Requirements 93.1.3 Abnormal Operation 103.1.4 Emergency Operation . 123.2 EPS Requi
11、rements 123.2.1 Inrush/Surge Current Transients 123.2.2 Reverse Current During Voltage Droop and Abnormal Operation . 123.2.3 Source Impedance 123.2.4 Faults 133.3 EPCE Requirements . 133.3.1 Normal Operation 133.3.2 Abnormal Operation 154. VERIFICATION . 215. VERIFICATION METHODS 215.1 Electrical P
12、ower Characteristics . 225.1.1 System Characteristics . 225.1.2 Normal Operation Requirements 235.1.3 Abnormal Operation 245.1.4 Emergency Operation . 245.2 EPS Requirements 245.2.1 Inrush/Surge Current Transients 245.2.2 Reverse Current During Voltage Droop and Abnormal Operation . 245.2.3 Source I
13、mpedance 245.2.4 Faults 245.3 EPCE Requirements . 255.3.1 Normal Operation 255.3.2 Abnormal Operation 266. NOTES 27APPENDIX A TEST METHODS 28APPENDIX B GENERAL DISCUSSION . 33SAE AS5698 Page 3 of 34 FIGURE 1 28 V NORMAL TRANSIENT RESPONSE 16FIGURE 2 28 V RIPPLE VOLTAGE SPECTRAL COMPONENTS 17FIGURE 3
14、 NORMALIZED 28 V AND 120 V INPUT IMPEDANCE MAGNITUDE LIMIT . 17FIGURE 4 28 V LOCAL STABILITY . 18FIGURE 5 28 V ABNORMAL VOLTAGE LIMITS FOR OVERVOLTAGE AND UNDERVOLTAGE 18FIGURE 6 120 V EPS NORMAL TRANSIENT RESPONSE . 19FIGURE 7 120 V RIPPLE VOLTAGE SPECTRAL COMPONENTS 19FIGURE 8 120 V LOCAL STABILIT
15、Y . 20FIGURE 9 120 V EPS ABNORMAL VOLTAGE LIMITS FOR OVERVOLTAGE AND UNDERVOLTAGE 20FIGURE 10 EPS NYQUIST STABILITY CRITERIA . 21 TABLE 1 POWER CHARACTERISTICS . 11SAE AS5698 Page 4 of 34 1. SCOPE This standard defines the requirements and characteristics of electrical power for spacecraft. This sta
16、ndard also defines analysis, verification, and testing methodologies to be used to ensure that the loads operate when connected to the specified power quality and performance as defined by this standard.1.1 Purpose The purpose of this electrical power quality standard is to ensure commonality, relia
17、bility, interchangeability, and interoperability for load applications between space application power systems that meet these requirements. 2. REFERENCES 2.1 Applicable Documents The following publications form a part of this document to the extent specified herein. The latest issue of SAE publicat
18、ions shall apply. The applicable issue of other publications shall be the issue in effect on the date of the purchase order. In the event of conflict between the text of this document and references cited herein, the text of this document takes precedence. Nothing in this document, however, supersed
19、es applicable laws and regulations unless a specific exemption has been obtained. 2.1.1 U.S. Government Publications Available from the Document Automation and Production Service (DAPS), Building 4/D, 700 Robbins Avenue, Philadelphia, PA 19111-5094, Tel: 215-697-6257, http:/assist.daps.dla.mil/quick
20、search/.MIL-STD-461F Requirements for the Control of Electromagnetic Interference Characteristics of Subsystems and Equipment2.2 Abbreviations and Definitions 2.2.1 Abbreviations AC alternating current A Ampere dB decibels DC direct current DUT device under test E3 Electromagnetic Environmental Effe
21、cts EMC Electromagnetic Compatibility EMI Electromagnetic Interference EPCE Electrical Power Consuming Equipment EPS Electrical Power System EUT Equipment Under Test FET Field Effect Transistor GSE Ground Support Equipment Hz Hertz kHz kilohertz MHz Megahertz s millisecond NVR No Verification Requir
22、ed POR Point of Regulation or Point of Reference for unregulated systems pps pulses per second PU Per Unit RC Resistor/Capacitor rms root mean square SAE AS5698 Page 5 of 34 TBD To Be Determined TBR To Be Resolved F microfarad V DC Volt direct current V p-p Volts peak-to-peak W Watt Zn normalized in
23、put load impedance 2.2.2 Definitions ABNORMAL OPERATION - Abnormal operation is that condition of the EPS wherein a fault or failure in the EPS distribution wiring, or connected loads, has occurred and the protective devices of the EPS are operating to isolate or remove the fault from the appropriat
24、e EPS interface. BRANCH CIRCUIT - A power distribution line that delivers power from an overcurrent protection device to an electrical load device. BUS CONTROL - A means of controlling the direction and flow of current across an interface. CLEARING TIME - The time for an overcurrent protection devic
25、e to interrupt a circuit fault. CURRENT LIMITING - The process of actively controlling the flow of electrical current to a level at, or below, a defined threshold when it might otherwise be exceeded. Also, the role of electrical protection controls that perform this function. DISTRIBUTION SYSTEM - T
26、he means to distribute power through the power system. DROP-OUT TIME - Drop-out time is the time interval during which the electric power is interrupted. Voltages will be below defined values for the duration of the drop-out and are assumed to fall to zero Volts. ELECTRIC POWER CONSUMING EQUIPMENT -
27、 EPCE is used in this document as a generic term to refer to any piece of electrical equipment acting as a load on the Spacecraft. . ELECTRIC POWER SYSTEM - The EPS consists of the electric power generation and distribution subsystems, including all devices up to the EPCE power interface such as gen
28、erators, energy storage devices, cables, switches, protective devices, converters, and regulators. ELECTROMAGNETIC COMPATIBILITY - The ability of systems, and EPCEs that are exposed to or use the electromagnetic spectrum to operate in the operational environments without suffering unacceptable degra
29、dation or causing unintentional degradation because of electromagnetic radiation. EMERGENCY OPERATION - Emergency operation occurs upon failure of a primary power generation/energy storage system and/or contingency cases requiring deep discharges users of electrical power. EPS POWER INTERFACE - The
30、EPS Power Interface is the point of connection for a fixed EPCE. For portable equipment, the EPS power interface is at the EPS receptacle. FAULT - A condition causing overcurrent on the EPS. FAULT CLEARING - The action in power system protection devices that disconnects a faulted line from the rest
31、of the system. FAULT CONTAINMENT - A mechanism to localize a circuit fault to the closest protective device. FAULT COORDINATION - Coordinating a series of protective devices in such a way as to make sure the protective device nearest to the fault clears the fault before affecting upstream switchgear
32、. SAE AS5698 Page 6 of 34 FEEDER LINE - Cables that distribute electrical power from a primary bus to lower level protective switchgear. GROUND - Common circuit reference point considered to have 0 V. HIGH CURRENT FAULT - A fault condition that produced very high currents generally conducting fault
33、current throught a hard physical connection. This condition is often referred to as a “bolted fault.“ HIGH IMPEDANCE FAULT - A fault condition that produces unacceptable currents but is not considered high currents. This fault is often considered the most dangerous and difficult to clear. This fault
34、 is often referred to as a “soft fault.“ IMPEDANCE - Electrical impedance describes the amplitudes of the voltage, current, and phase. Impedance is the complex quantity . INRUSH CURRENT - Inrush current is defined as EPCE initialization current to energize loads or portions thereof. The current enve
35、lope is the total charging current in amp-seconds that starts at the instant current exceeds the rated load current of the EPCE and ends once the input current returns to the rated load current value. INSTABILITY - Characterized by an output or internal state of a system growing without bounds. INTE
36、RFACE POWER - The electrical power supplied/consumed to/from an electrical load. LEAKAGE CURRENT - Current flow as a result of imperfect insulation or semiconductor materials. LOCAL STABILITY - A limited measure of EPCE stability under representative (or typical) source impedance conditions. NOMINAL
37、 RATING - An approximate value used to indicate its intended application or to differentiate it from similar devices with different ratings. NUISANCE TRIPPING - An inadvertent interruption of an EPCE by the protection switchgear during normal operation of the load. NORMALIZED INPUT IMPEDANCE - EPCE
38、Input impedance curve scaled to 0dB (one ohm) at zero frequency. OVERCURRENT - A situation where larger than intended electric currents exist in a circuit OVERCURRENT PROTECTION - The limiting of excessive circuit current by some means. OVERVOLTAGE - A potentially hazardous condition when the voltag
39、e in a circuit or part of it is raised above the system upper design limit. PEAK RIPPLE VOLTAGE - The absolute value of the maximum difference between the steady state and instantaneous voltage. The peak ripple voltage is the sum total peak voltage amplitude of a ripple composite, including nonperio
40、dic events that can be present on the EPS for a fixed bandwidth. PEAK-TO-PEAK VOLTAGE - A voltage measurement of a periodic voltage waveform from the lowest well to the highest point (peak). POWER QUALITY - Electrical characteristics that allow the system to function properly without significant los
41、s of performance or life. PULSED LOADS - EPCE that operates in a periodic manner with a frequency below 30 Hz. SAE AS5698 Page 7 of 34 RATED LOAD CURRENT - The maximum current draw from a load after all start-up or mode change transients have settled out. RATED POWER - The nominal output power for E
42、PS branch circuits or power consumption of an EPCE. REVERSE CURRENT - Direct current flowing in the opposite direction from the intended circuit design. For loads, this can be created from the energy discharge of a circuit due to counter electromagnetic force due to regenerative loads (such as motor
43、 controllers or actuators) or under a fault condition upstream of the load power interface. RIPPLE VOLTAGE AMPLITUDE - Ripple voltage is the RMS value of all ac voltage components that are superimposed on the steady-state dc voltage. RIPPLE VOLTAGE SPECTRUM - The frequency distribution of ripple vol
44、tage components. SHORT CIRCUIT - Abnormal low impedance/resistance connection between nodes of an electrical circuit at different voltages. SINGLE-POINT GROUND - Single-Point Ground is a single ground reference to structure. STABILITY - The quality of electrical device operation wherein key characte
45、ristics resist deviation from intended values under both static and dynamic conditions. SURGE CURRENT - Surge current is defined as a transient, or pulsed, current, due to operation of an EPCE that is greater than the average over any interval of time. SWITCHGEAR - The combination of electrical/elec
46、tronic disconnects or fuses used to operate/isolate electrical equipment. Switchgear can be designed to both operate and protect (clear circuit faults) equipment. TRANSIENT RESPONSE - A disturbance in an electrical system brought about by a sudden change of load. TWO-WIRE - An electrical distributio
47、n system using separate supply and return conductors to supply electrical power to an EPCE. VOLTAGE DROOP - The reduction in output voltage due to a fault or failure. VOLTAGE SPECTRUM - A graph of individual voltage intensity components plotted against frequency. 3. GENERAL REQUIREMENTS 3.1 Electric
48、al Power Characteristics The following sections specify the characteristics for electric power supplied to electrical loads at the point of connection with an electric power user. The EPS consists of the electric power-generating source (e.g., generators, batteries, fuel cells, solar arrays, and dis
49、tribution subsystems) including the associated cables, switches, protective devices, converters, and regulators. The EPS performance is specified at the electrical connection of individual electrical EPCEs (electrical loads).Power quality is directly related to the effects produced by electromagnetic interference (EMI), regenerative energy, and volt
