ISO 24065:2023
(Main)Aerospace — High-power solid-state power controller — General performance requirements
Aerospace — High-power solid-state power controller — General performance requirements
This document specifies the general performance requirements and test methods to determine the performance of the high-power solid-state power controller (HPSSPC) for use in the primary power distribution of aircrafts.
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 24065
First edition
2023-10
Aerospace — High-power solid-
state power controller — General
performance requirements
Reference number
© ISO 2023
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ii
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Requirements . 6
4.1 Detail requirements . 6
4.2 Electrical characteristics . 6
4.3 Performance . 6
4.3.1 Control signals . . 6
4.3.2 Turn-on and turn-off time . 6
4.3.3 Load voltage rise and fall time (soft on/off function). 6
4.3.4 Isolation . 6
4.3.5 Control signal levels . 6
4.3.6 Voltage drop. 7
4.3.7 Off state leakage current. 7
4.3.8 Off state output voltage . 7
4.3.9 Power dissipation . 7
4.3.10 Overload characteristics . 7
4.3.11 State indication . 7
4.3.12 HPSSPC trip-free characteristics . 7
4.3.13 Zero voltage turn-on and zero current turn-off (AC HPSSPC) . 8
4.3.14 Reverse current . 8
4.3.15 Exponential rate of voltage rise . 8
4.3.16 Arc fault characteristics . 8
4.3.17 Built-in test . 8
4.3.18 Setting change for the rated current . 9
5 Quality assurance provisions on electrical characteristics . 9
5.1 General . 9
5.2 Control signals . 9
5.2.1 General . 9
5.2.2 Turn-on signal . 9
5.2.3 Turn-off signal . 10
5.3 Turn-on and turn-off time . 10
5.4 Load voltage rise and fall time . 10
5.5 Isolation . 10
5.6 Control signal levels . 11
5.7 Voltage drop . 11
5.8 Off state leakage current . 11
5.9 Off state output voltage . 11
5.10 Power dissipation . 11
5.11 Overload characteristic tests. 11
5.11.1 Current limiting . . 11
5.11.2 HPSSPC trip characteristics .12
5.12 State indication signal(s) .12
5.13 HPSSPC trip-free characteristics .12
5.14 Zero voltage turn-on (ZVTO) and zero current turn-off (ZCTO) .12
5.15 Reverse current .12
5.16 Exponential rate of voltage rise . 13
5.17 Arc fault characteristics . 14
5.17.1 Guillotine test . 14
5.17.2 Wet arc fault test . 16
iii
5.17.3 Intermittent connection test . 17
5.17.4 Compatibility with normal load . 20
5.17.5 Compatibility with arc fault of another line . 20
5.18 Built-in test. 21
5.19 Setting change for the rated current . 21
Bibliography .23
iv
Foreword
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Subcommittee SC 1, Aerospace electrical requirements.
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v
Introduction
For aircrafts electrical power systems, there is a trend toward higher voltage and higher current
systems. There are several advantages in using a solid-state power controller (SSPC) for the distribution
system. A standard of the SSPC for lower electrical power supply has been established (ISO 27027); but
the standard for the SSPC for higher electrical power supply, which is intended for application in the
primary power distribution of aircrafts, has not been established. Therefore, it is necessary to develop
a standard for the high-power solid-state power controller (HPSSPC).
The purpose of this document is to standardize the requirements for HPSSPCs that are physically and
environmentally diversified.
The HPSSPC:
a) consists of a solid-state switching device and its driver circuit;
b) turns on or off the power output by receiving the control signal;
c) detects the over current in the load which results in limiting or shutting down this current, and/or
optionally detects the arc fault in the circuit which results in shutting down the fault;
d) has the built-in test function which can detect the health status of itself;
e) indicates the on or off status of the power output.
In order to satisfy this purpose, this document specifies requirements such as physical, environmental
and individual items in accordance with the detail requirements that are issued individually.
vi
INTERNATIONAL STANDARD ISO 24065:2023(E)
Aerospace — High-power solid-state power controller —
General performance requirements
1 Scope
This document specifies the general performance requirements and test methods to determine the
performance of the high-power solid-state power controller (HPSSPC) for use in the primary power
distribution of aircrafts.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 1540, Aerospace — Characteristics of aircraft electrical systems
ISO 7137:1995, Aircraft — Environmental conditions and test procedures for airborne equipment
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
turn-on time
time interval between the initiation of the turn-
on signal (3.5) or the latest frame of the turn-on command data packet via the control signal bus and the
time when the output reaches 90 % of its steady-state on value
Note 1 to entry: Shown in Figure 1 a).
a) DC HPSSPC
b) AC HPSSPC
Key
Y load voltage
V voltage
t time
T turn-on time
ON
T turn-off time
OFF
T rise time
R
T fall time
F
1 rated control signal (which can optionally consist of control bus)
2 turn on (min)
3 turn off (max)
4 zero voltage turn-on
5 zero current turn-off
Figure 1 — Illustration of timing characteristics
3.2
turn-on time
time interval between the initiation of the turn-on signal (3.5)
or the latest frame of the turn-on command data packet via the control signal bus and the time when
the output switch is on at zero-crossing
Note 1 to entry: Shown in Figure 1 b).
3.3
turn-off time
time interval between the initiation of the turn-
off signal or the latest frame of the turn-off command data packet via the control signal bus and the
time when the output reaches 10 % of its steady-state on value
Note 1 to entry: Shown in Figure 1 a).
3.4
turn-off time
time interval between the initiation of the turn-off signal or
the latest frame of the turn-off command data packet via the control signal bus and the time when the
output switch is off at zero-crossing
Note 1 to entry: Shown in Figure 1 b).
3.5
turn-on signal
control signal level or turn-on command data packet via the control signal bus at which the power
controller is turned on
3.6
turn-off signal
control signal level or turn-off command data packet via the control signal bus at which the power
controller is turned off
3.7
load voltage rise and fall time
time interval between 10 % and 90 % of the steady state load voltage (3.10) value
Note 1 to entry: This definition applies to DC devices and non-zero-crossing turn-off AC devices.
Note 2 to entry: The load voltage rise and fall time for DC devices is shown in Figure 1 a).
[SOURCE: ISO 27027:2014, 3.4, modified — "(DC devices and non-zero-crossing turn-off AC devices)"
has been moved from the term to Note 1 to entry; the reference to Figure 1 a) has been moved from the
end of the definition to Note 2 to entry.]
3.8
soft on/off
function for the power output current to increase linearly with the turn-on signal (3.5) or the turn-on
command data packet via the control signal bus and to decrease linearly with the turn-off signal or the
turn-off command data packet via the control signal bus
3.9
supply voltage
voltage applied between the power input terminal of the HPSSPC (3.13) and the power ground
3.10
load voltage
voltage between the power output terminal of the HPSSPC (3.13) and the power ground
3.11
voltage drop
voltage across load and line terminals of the HPSSPC (3.13) in the on state (3.20) at the specified load
3.12
rated current
supplied maximum current that the HPSSPC (3.13) continuously outputs from the output terminal
without tripping
3.13
HPSSPC
high-power solid-state power controller
solid-state power controller (SSPC) which is applied on primary power distribution
3.14
power dissipation
power loss which includes all power dissipated in the power switching circuit, due to internal leakage
currents and power supplies
Note 1 to entry: When the HPSSPC (3.13) is off, the power dissipation includes only dissipation due to leakage
currents and internal power supplies.
3.15
HPSSPC trip
automatic reversion to the off state (3.21) of the HPSSPC (3.13) output caused by an overcurrent or a
short circuit (3.22) condition or detection of an arc fault (3.28)
3.16
HPSSPC trip-free
feature which prevents subsequent re-closing unless preceded by a reset (3.19) signal, when the HPSSPC
(3.13) has tripped due to an overcurrent or a short circuit (3.22) condition or detection of an arc fault
(3.28)
3.17
trip time
time interval between the application of an overcurrent or a short circuit (3.22) condition or detection
of an arc fault (3.28) and the 10 % value of rated output current
Note 1 to entry: In general, the higher the over current condition, the shorter the trip time.
3.18
trip curve
curve which sets the minimum and maximum trip points of the HPSSPC (3.13) and is plotted as current
versus time
3.19
reset
restoration of the tripped HPSSPC (3.13) to a state from which it can be turned on
3.20
on state
condition in which, with the turn-on signal (3.5) applied, the device allows power to be passed to the
load
[SOURCE: ISO 27027:2014, 3.6]
3.21
off state
condition in which, with the turn-off signal applied, the device prevents power from being passed to the
load
[SOURCE: ISO 27027:2014, 3.5]
3.22
short circuit
circuit with the impedance of less than 1 mΩ applied between the output terminal and ground
[SOURCE: ISO 27027:2014, 3.13]
3.23
current limiting
function to limit the power output current to the required level within required time from overload or
short circuit (3.22) conditions
Note 1 to entry: Shown in Figure 2.
[SOURCE: ISO 27027:2014, 3.2, modified — The reference to Figure 2 has been moved from the end of
the definition to Note 1 to entry.]
Key
I load current
t time
1 peak let-through current
2 specified current limit
3 ripple
Figure 2 — Overload let-through current
3.24
peak let-through current
peak value of the current at the maximum system voltage that the HPSSPC (3.13) conducts for a specified
time interval without damage
3.25
zero voltage turn-on
characteristic that requires the HPSSPC (3.13) to turn on only at the half-cycle zero-crossing point,
regardless of when the control signal is applied
Note 1 to entry: This characteristic applies only to AC devices.
3.26
zero current turn-off
characteristic that requires the HPSSPC (3.13) to turn off only at the half-cycle zero-crossing point,
regardless of when the control signal is removed
Note 1 to entry: This characteristic applies only to AC devices.
3.27
reverse current
current into the load terminal of the HPSSPC (3.13) from the load energy source
3.28
arc fault
sustained luminous discharge of electricity across a gap in a circuit or between conductors
Note 1 to entry: Arc impedance can reduce low-voltage fault current magnitudes appreciably.
[SOURCE: ISO 27027:2014, 3.1]
3.29
parallel arc fault
arc fault (3.28) condition in which arcing occurs in a circuit from line-to-line or line-to-ground and not
through any load(s)
Note 1 to entry: Only the arc impedance and the system current impedance limit the magnitude of the arc fault
current.
[SOURCE: ISO 27027:2014, 3.7]
3.30
series arc fault
arc fault (3.28) condition in which the current passes through the arc and each circuit load
Note 1 to entry: The load equipment limits the magnitude of the arc fault current.
[SOURCE: ISO 27027:2014, 3.12]
4 Requirements
4.1 Detail requirements
The individual item requirements shall be specified in accordance with the detail requirements that
are issued individually. ISO 7137 should be used for the s
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