ISO 23316-5:2023

INTERNATIONAL ISO
STANDARD 23316-5
First edition
2023-10
Tractors and machinery for
agriculture and forestry — Electrical
high-power interface 700 V DC / 480 V
AC —
Part 5:
DC operation mode
Reference number
© ISO 2023
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and symbols . 1
3.1 Terms and definitions . 1
3.2 Symbols . 2
4 System overview . 3
4.1 General . 3
4.2 Operation with single CS . 4
4.3 Operation with MCS . 5
5 DC specification. 8
5.1 Voltage form and quality . 8
5.1.1 System voltage: values and ranges . 8
5.1.2 Voltage ripple . . 8
5.1.3 Continuous DC current . . . 9
5.1.4 Peak current . 9
5.1.5 Current specific communication parameters . 10
5.1.6 Voltage dips and recovery time . 10
5.1.7 Overvoltage protection. 10
5.1.8 Overcurrent protection . 10
5.1.9 System inductance .12
5.1.10 DC link capacitance .12
5.1.11 Y-capacitors, parasitic capacitances . 13
5.1.12 DC Link pre-charging . 13
5.2 DC link discharging procedure .15
5.2.1 General .15
5.2.2 Connection of MCS .15
5.3 Compatibility criteria for PS, HPI and load . 16
5.3.1 Block diagram . 16
5.3.2 Value ranges for system components: . 17
5.3.3 Limitations on ripple current . 17
5.3.4 Test methods . 18
5.3.5 Ripple current in case of MCS . 19
5.3.6 Limited operation of source-load(s) combinations with respect to ripple
currents . 20
5.3.7 Energy feedback . . 20
5.3.8 Functional requirements — Energy feedback over time . 21
5.4 Overload protection . 21
Annex A (informative) Estimation methods for DC link film capacitors .22
Annex B (informative) Technical details .24
Bibliography .36
iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
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electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO document should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 23, Tractors and machinery for agriculture
and forestry, Subcommittee SC 19, Agricultural electronics
A list of all parts in the ISO 23316 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Introduction
ISO 23316-1 describes the general purpose and structure of standards in the ISO 23316 series, including
common elements and definitions shared within all parts of the ISO 23316 series.
The purpose of the ISO 23316 series is to provide design and application standards covering
implementation of electrical high power interface with a nominal voltage of 700 VDC/480 VAC for
agricultural and forestry machinery.
The ISO 23316 series specifies physical and logical interface requirements that provide interoperability
and cross compatibility for systems and equipment operating at nominal voltages of 700 VDC/480 VAC.
The following are not within the scope of ISO 23316:
— service, maintenance, and related diagnostics;
— functional safety;
— control strategies for high power sources and loads;
— application-specific strategies and operational modes;
— component design;
— energy storage systems, e. g. super-capacitors or batteries;
— multiple electrical power sources supplying a common DC link.
It is permitted for partial systems or components to be compliant to the ISO 23316 series by applying
all applicable requirements, e.g. for the plug, receptacle or inverters, on a tractor or implement.
NOTE If a DC-mode only HPI is provided, it is not necessary to comply with part 4 describing AC-mode, as it
is not applicable. If an AC-mode only HPI is provided, it is not necessary to comply with this document, as it is not
applicable.
v
INTERNATIONAL STANDARD ISO 23316-5:2023(E)
Tractors and machinery for agriculture and forestry —
Electrical high-power interface 700 V DC / 480 V AC —
Part 5:
DC operation mode
1 Scope
This document specifies measures applicable to the class B2 voltage DC bus of a supply system which is
intended to power detachable electrical CS(s).
— electrical specification of the high power interface
— operating modes (e. g. initialization, normal operation, energy feedback, connect/disconnect
procedures and disconnect in case of malfunction)
— Communication parameters (basic framework: signals, ranges, units, states of supply system and
CS)
The document contains simplified electrical diagrams showing specific aspects of the required
functionality.
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 16230-1:2015, Agricultural machinery and tractors — Safety of higher voltage electrical and electronic
components and systems — Part 1: General requirements
ISO 23316-1, Tractors and machinery for agriculture and forestry — Electrical high-power interface 700 V
DC / 480 V AC — Part 1: General
ISO 23316-2, Tractors and machinery for agriculture and forestry — Electrical high-power interface 700 V
DC / 480 V AC — Part 2: Physical interface
ISO 23316-3, Tractors and machinery for agriculture and forestry — Electrical high-power interface 700 V
DC / 480 V AC — Part 3: Safety requirements
1)
ISO/FDIS 23316-6:— , Tractors and machinery for agriculture and forestry — Electrical high power
interface 700 V DC / 480 V AC — Part 6: Controls communication
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 23316-1, ISO/FDIS 23316-6:—
and the following apply.
1) Under preparation. Stage at the date of publication: ISO/FDIS 23316-6:2023.
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/
3.1.1
device under test
DUT
single component or combination of components as defined to be tested
[SOURCE: ISO 10605:2008, 3.3]
3.2 Symbols
C DC link capacitance PS
DC src
C DC link capacitance CS
DC ld
C Y-Capacitor CS
y ld
C Y-Capacitor PS
y src
L cable inductance
cab
L inner source inductance
i src
R inner source resistance
i src
R cable resistance
cab
R contact resistance
cont
m inverter modulation index representing the amplitude of the fundamental output voltage U
normalized by the DC supply voltage U , so m= U /U
DC 0 DC
⧍U voltage ripple
C DC link capacitor
DC
I peak current
pk
I root mean square current
rms
f switching frequency
sw
min minimum
4 System overview
4.1 General
Key
ACL AC load (e.g. electric motor)
APP application
C controller of a device
C DC link capacitor
DC
CE combustion engine
DCLNK DC link
G generator (as example of an electric power source)
HPI-C High Power Interface - Control
HPI-MC High Power Interface - Master Control
INV inverter (DC/AC converter)
REC rectifier (AC/DC power converter)
S switch (contactor or solid state switch, including pre- and discharge unit)
S-C switch controller
T transmission
TC task controller
TIM-C Tractor Implement Management Client
TIM-S Tractor Implement Management Server
VT virtual terminal (user interface, e.g. display)
I supply system
II consumer system
1 high power interface
2 ISOBUS connector
3 power lines
4 ISOBUS
5 supply system communication bus (e.g. tractor bus)
6 consumer system communication bus (e.g. implement bus)
7 interlock signal
8 feedback signal (by e.g. a sensor)
9 interlock signal line breaker
power connection
signal/bus connection
optional connection
defines focus of document
Figure 1 — Exemplary system schematics
The system consists at least of an electrical PS with generator and control providing DC power
on a DC link and a CS, which is connected by an HPI and communication line in accordance with
ISO/FDIS 23316-6:—. System schematics are shown in Figure 1.
NOTE Depending on design, a discharge unit can be needed for implements.
The architecture of the load depends upon the specific application and can have any combination
of resistive, inductive and capacitive elements. The common base is the voltage provided by the
source (and specified in the subsequent chapters) and the communication interface according to
ISO/FDIS 23316-6:—. A voltage source can have multiple HPIs.
The minimum VC-B2 system consists of at least one PS and one APP. The VC-B2 system is based on an IT
system. Each implement may contain many different VC-B2 devices.
4.2 Operation with single CS
At the simplest level, only one CS (e.g. implement) is attached on the supply system (e.g. tractor), where
the PS is located. The single CS can contain one or more independent VC-B2 devices. Such a configuration
is shown in Figure 2 and is the basis for the following figures with MCS.
Key
ACL AC Load (e.g. electric motor)
G Generator
INV Inverter
REC Rectifier
S Pre- / discharge / disconnecting device
I supply system (e.g. tractor)
II consumer system (e.g. implement)
1 high power interface
Figure 2 — Single implement block diagram
4.3 Operation with MCS
It is also possible to attach an MCS to a supply system (e.g. tractor). Each can contain one, or more VC-B2
devices. If an MCS is attached to one supply system, each CS needs its own HPI-C. Figures 4 to 6 show
some, but not all possible, configurations.
The first supply system in the topology (typically located on tractor, or a PTO generator) shall provide
the sum of the power of the connected CS. In case of power/current restrictions due to higher total
demand compared to capabilities, one of these two load balancing options shall be used.
a) The HPI-MC shall control the power distribution of all other connected combinations.
b) The HPI-MC shall control the power distribution of the first supply system connected subsystems
(which consist of several VC-B2 devices).
Figure 3 shows a configuration where several CS are attached on supply system, and each has its own
HPI (maximum allowed number of implements in accordance with ISO 11783).
Key
ACL AC load (e.g. electric motor)
G generator
INV inverter
REC rectifier
S pre-/discharge/disconnecting device
I supply system (e.g. tractor)
II consumer system (e.g. implement)
1 high power interface
Figure 3 — Configuration with several parallel CS each at a separate connector
Figure 4 shows a configuration where a CS is attached on supply system’s front and several CS are
attached on supply system’s rear and each has its own HPI.
Key
ACL AC Load (e.g. electric motor)
G generator
INV inverter
REC rectifier
S pre-/discharge/disconnecting device
I supply system (e.g. tractor)
II consumer system (e.g. implement)
1 high power interface
Figure 4 — Configuration with a front CS and several rear CSs each with a separate connector
Figure 5 shows a configuration where three CS are attached in series, thus only one tractor HPI is used
and two CS are providing the HPI to the following one.
Key
ACL AC load (e.g. electric motor)
G generator
INV inverter
REC rectifier
S pre-/discharge/disconnecting device
I supply system (e.g. tractor)
II consumer system (e.g. implement)
1 high power interface
Figure 5 — Configuration with three CS in series
Figure 6 shows a configuration where series and parallel connection of CSs are combined.
Key
ACL AC load (e.g. electric motor)
G generator
INV inverter
REC rectifier
S pre-/discharge/disconnecting device
I supply system (e.g. tractor)
II consumer system (e.g. implement)
1 high power interface
Figure 6 — Configuration with front CS, a single rear CS and two rear CS in series
5 DC specification
5.1 Voltage form and quality
5.1.1 System voltage: values and ranges
For the purposes of this document, the voltage values and ranges given in ISO 23316-1 apply.
5.1.2 Voltage ripple
5.1.2.1 General
Periodic voltage ripple is generated due to residual incomplete suppression of an alternating wave after
rectification from switching of the inverters used in the PS and loads.
5.1.2.2 Ripple specification for a power source (PS)
For the first PS, ±2 % of the nominal voltage shall not be exceeded.
NOTE If an implement serves as PS, it might not be possible to satisfy this requirement as well.
5.1.2.3 Ripple specification for load(s)
±5 % of the nominal voltage shall not be exceeded.
NOTE Different levels for the PS and loads are defined to avoid exceeding the specified limits in case of DC
bus resonances.
5.1.3 Continuous DC current
The continuous DC current is the current, which the PS is able to supply.
The maximum continuous DC current is restricted by three limits:
— continuous current the PS is able to supply, which is I = P /U (Signal according
cont source cont source nom
to ISO/FDIS 23316-6:—: “PC/S current capability–continuous)”;
— current carrying capability of the HPI (as defined in ISO 23316-2:2023, 4.5.6);
— continuous current limitation by the cable cross section from HPI to CS, defined and transferred by
the HPI-C (e.g. implement) to the HPI-MC (e.g. tractor) (Signal according to ISO/FDIS 23316-6:—:
“Load current demand– maximum continuous”).
The lowest value of these limits is the maximum current, which can be supplied by the PS continuously.
This is transferred from the HPI-MC to the HPI-C (Signal according to ISO/FDIS 23316-6:—: “PC/S
current calculated–continuous”).
5.1.4 Peak current
Each system part (PS and load) has its own peak current limit. The peak current is the maximum
amount of current which the output is capable of sourcing for brief periods of time. Characterizing
values are amplitude, duration and minimum repetition rate. It mainly depends on the physical limits of
the electrical hardware used (current carrying capability, heat dissipation, etc.).
Applications on implements or attachments can have load variations causing the occurrence of peak
currents. The aim is not to overload the PS, cables and HPI contacts by the load.
The maximum peak DC current is restricted by three limits:
— peak current the PS is able to supply, which is I = P /U (Signal according to
peak source peak source nom
ISO/FDIS 23316-6:—: “PC/S current capability–peak”);
— current carrying capability of the HPI (as defined in ISO 23316-2:2023, 4.5.6);
— peak current limitation by cable cross section from HPI to CS, defined and transferred by the HPI-C
(e.g. implement) to the HPI-MC (e.g. tractor) (Signal according to ISO/FDIS 23316-6:—: “Load current
demand–maximum peak”).
The lowest value of these limits is the peak current, which can be supplied by the PS. This is transferred
from the HPI-MC to the HPI-C (Signal according to ISO 23316-6: “PC/S current calculated–peak”).
The following cases of operation will occur:
a) I > I → operation possible
peak (PS) peak (load)
b) I ≤ I → application specific, if operation possible
peak (PS) peak (load)
c) I << I → use of application is unlikely
peak (PS) peak (load)
5.1.5 Current specific communication parameters
To establish communication between supply system and CS, the PS shall send its specific continuous
and peak current limits as defined in ISO/FDIS 23316-6:—.
NOTE 1 The CS decides with respect to the specific application, if normal or restricted operation is possible.
NOTE 2 In case of multiple HPIs, the operator shall decide if the operation makes sense.
5.1.6 Voltage dips and recovery time
Voltage dips are the temporary deviation of the DC bus voltage from its normal value. It does not include
the periodic ripple.
If the current requested by a CS exceeds the maximum current supply capability of the PS for a limited
time period, the voltage will dip. Alternatively, if the CS is characterized by a rapidly changing rate of
the requested power (dimension: kW/s) the source voltage may dip. Recovery time is determined by
peak current capability/request of PS and load and their control loop responses.
Communication between supply system and CS during initialization shall be in accordance with
ISO/FDIS 23316-6:—. First, the PS shall provide its system limits. With this information the CS shall
decide whether normal, restricted or no operation is possible (application specific).
5.1.7 Overvoltage protection
5.1.7.1 Operational states leading to overvoltage in the DC system
Overvoltage can be caused by the following events:
— Energy feedback from load to PS. For more details refer to 5.3.7 “energy feedback”).
— Energy surplus in the DC link circuit (energy coming from both sides)
— Oscillations between components on the DC link circuit
5.1.7.2 Functional requirements
Measures to avoid overvoltage shall be taken on the PS and may additionally be taken on the CS to limit
the voltage to a level as defined in ISO 23316-1. Details are defined in 5.3.7.
Depending on the amount of the expected overvoltage, one or more of the following measures shall be
taken:
— dissipating energy by brake chopper;
— storing surplus energy in appropriate devices (e.g. capacitor, battery, flywheel storage);
— cutting off the system from supplies;
— feeding back energy to energy source, e.g. diesel engine.
5.1.8 Overcurrent protection
5.1.8.1 Operational states leading to overcurrent in the DC system
Overcurrent can be caused by the following events:
— power requirement of the load exceeds the maximum available power (of the PS);
— high energy feedback from load to PS;
— system malfunctions (e. g. short-circuits on PS or load).
5.1.8.2 Continuous and peak current on PS and CS
The maximum current, which is expected, refers to the installed power each on PS (tractor) and CS
(implement). Thus, PS and CS(s) have their own current carrying capability, which shall not be exceeded
in order to protect their own devices (e.g. cables, connectors, switches, etc.). In the connected DC-
system, a continuous current and a peak current for the system are defined. They are determined by
the PS and depend on the maximum power the PS is able to provide. The continuous current which can
be transferred by the HPI as a maximum is a limit which shall not be exceeded (see ISO 23316-2). These
figures are absolute system limits.
5.1.8.3 Requirements
5.1.8.3.1 General
Each unit (PS or load) connected to the DC link circuit shall prevent the current exceeding the maximum
permitted value for itself.
Devices to prevent from overcurrent shall be one of the following:
— fuses;
— circuit breakers;
— switches (e.g. relays).
NOTE The situation can be compared with a standard grid application: Incoming lines to a house are fused
with higher current values than separate rooms or special equipment within a house.
5.1.8.3.2 PS current less than load current
This applies if the current provided by the PS is less than the maximum which can be consumed by the
load I <= I .
max (PS) max (load)
This is a special situation. If the tractor-implement combination is allowed to work (to be handled
during initial communication; application specific, see ISO/FDIS 23316-6:—), the maximum power on
load side shall be limited to a value so that the maximum current of PS is not exceeded. Otherwise the
operation of this specific tractor-implement combination shall not be allowed. Each part of the system
shall protect itself against overcurrent.
In case of multiple implement operation the sum current of all implements can exceed the current
capability of the PS (see also “multiple implements operation”). During initialization the sum current
shall be matched.
5.1.8.3.3 Source current greater than load current
I > I
peak(PS) peak(CS)
In this case, the load-source combination is operating within the specified limits. Therefore, no overload
is occurring.
5.1.8.4 Overcurrent protection requirements
PS and load shall be protected against overcurrent. Because the PS can supply the load up to its
specified maximum, an overcurrent protection device (OPD, e.g. fuses, circuit breakers, switches) is
not sufficient. Typically, the PS inverter has an electronic current limitation. On the CS side, OPDs shall
protect devices and sections of different cable cross sections. See Table 1 and Figure 7.
Table 1 — Overcurrent protection requirements
PS CS
cross section shall be dimensioned according to maxi- cross section close to HPI shall be dimensioned to
mum current to be transferred transfer the overall CS current
PS converter shall have an electronic overcurrent pro- “general” OPD shall protect the cable from HPI to dis-
tection, so no OPD required tribution box
single OPD (fast-blow) shall protect each individual
drive unit (cable cross section and OPD usage accord-
ing to individual current consumption), can be part of
the inverter
Key
ACL AC load (e.g. electric motor)
DB distribution box
G generator
INV inverter
OPD overcurrent protection device
REC rectifier
I supply system (e.g. tractor)
II consumer system (e.g. implement)
1 high power interface
Figure 7 — Simplified dc bus diagram for a supply system and CS showing OPD locations
5.1.9 System inductance
The system inductance is a parasitic value, which mainly is a result of the VC-B2 DC harness length and
geometry in the system (consisting of PS, load and HPI).
NOTE An expected value range is helpful with regard to the equivalent circuit diagrams, see B.4).
5.1.10 DC link capacitance
5.1.10.1 General
The capacitance of the DC link capacitors connected between the + and – lines of the DC link circuit in
the PS or load(s).
The DC voltage typically is provided by an inverter. The switching frequency and its harmonics are
present on the DC side of the inverter and smoothened by a DC link capacitor in order to fulfil the
permitted voltage ripple. Commonly, each inverter connected to a DC link system contributes to the
overall system DC link capacitance.
5.1.10.2 Requirements
PS and CS shall conform with the allowed voltage ripple. This results in a DC link capacitance value on
PS and load(s) (see 5.1.3“voltage ripple”).
The maximum amount of DC link capacitance defined in 5.2.1 “value ranges” shall not be exceeded.
NOTE 1 In order to ensure a correct pre-charging procedure, the actual capacitance values used on the CS are
communicated to supply system according to ISO/FDIS 23316-6:—. A capacitance value of zero means that the CS
will do the pre-charge on its own.
NOTE 2 Approaches for a first rough estimate of the total DC link capacitance are listed in Annex A.
5.1.11 Y-capacitors, parasitic capacitances
Y-capacitors are part of an inverter and connect positive and negative wires to the chassis in order
to fulfil EMC regulations. Parasitic capacitances result from system geometry (e.g. stray capacitance
between positive and negative wires to chassis).
The capacitances shall taken into account to ensure the integrity of the IT system. If the energy stored
in all Y-capacitors (required to fulfil EMC regulations) and parasitic capacitances of the system exceed a
certain value, dangerous currents through human body can occur under certain fault conditions.
To avoid dangerous currents through human body, follow the protection measures in accordance with
ISO 23316-3 and ISO 16230-1.
5.1.12 DC Link pre-charging
5.1.12.1 General
A controlled charging of a DC link capacitor equalizes its voltage with a source to limit the surge current
in case of a low impedance connection.
To achieve this, the following methods may be used to perform the pre-charge process:
— Passive pre-charge: Pre-charge process performed using a resistor, in order to reduce the peak
current.
— Active pre-charge: Pre-charge process performed using power electronics to control the pre-charge
current over time.
5.1.12.2 Type and position of pre-charge unit
The supply system (typically tractor) shall provide at least a passive pre-charge unit to charge the DC
link capacitors. Alternatively, an active pre-charge unit via using power electronics may be installed.
Key
ACL AC load (e.g. electric motor)
APP application
C controller of a device
C DC link capacitor
DC
CE combustion engine
DCLNK DC link
G generator (as example of an electric power source)
HPI-C high power interface - control
HPI-MC High Power Interface - Master Control
INV inverter (DC/AC converter)
L load
REC rectifier (AC/DC power converter)
S switch (contactor or solid state switch, including pre- and discharge unit)
S-C switch controller
T transmission
TC task controller
TIM-C TIM (Tractor Implement Management) client
TIM-S TIM server
VT virtual terminal (user interface, e.g. display)
I supply system
II consumer system
1 high power interface
2 ISOBUS connector
3 power lines
4 ISOBUS
5 supply system communication bus (e.g. tractor bus)
6 consumer system communication bus (e.g. implement bus)
7 interlock signal
8 feedback signal (by e.g. a sensor)
9 interlock signal line breaker
Figure 8 — General location of the pre-charge unit
NOTE 1 The supply system always provides at least a passive pre-charge unit. An additional pre-charge unit
on a CS is an option.
NOTE 2 If electrolytic capacitors are used as DC link capacitance on the load, special handling due to their
specific characteristics are given in B.2.
5.1.12.3 Functional requirement — Charge current
The maximum initial charging current shall not exceed 20 A. The maximum allowed current
consumption of the load(s) during pre-charging over the DC link circuit shall not exceed 0,5 A.
If these conditions are not sufficient to charge the load(s) DC link circuit, the CS shall provide an
autonomous pre-charge unit.
NOTE If an electronic pre-charge unit is used, the initial current has AC and DC components. The current is
calculated as RMS value over a time period of 100 ms.
5.1.12.4 Functional requirement — Autonomous pre-charge
If the value for the DC link capacitor (sent via communication according to ISO/FDIS 23316-6:—) is
equal to zero, the supply system shall expect an autonomous pre-charging by the CS.
NOTE 1 In this case, the DC link voltage is switched on without initiating a pre-charge procedure from PS side.
NOTE 2 An example for a pre-charge state machine is shown in B.3.
5.2 DC link discharging procedure
5.2.1 General
After use or in case of faults (e.g. severing of the cable, unplugging during operation), the DC link
capacitors are required to be discharged within a certain time period.
If the VC-B2 supply of the CS is interrupted, a function shall be provided on the CS to ensure a controlled
capacitor discharge within the time limit defined in ISO 23316-3:2023, 5.5.3.1.
In the case of cable severing, the supply system shall switch off the HPI, and the CS shall discharge its
own DC link capacitor and supply system shall de-energize the HPI.
5.2.2 Connection of MCS
5.2.2.1 General application
Combinations of front and rear CS as well as several rear combinations are commonly used. These
applications shall be handled by the HPI to fulfil this requirement.
5.2.2.2 Interlock function
The interlock function is provided per HPI on one hand as a measure to check that connector and socket
are plugged correctly and on the other hand to check, whether a reliable connection between CS and
supply system is established.
NOTE 1 Internal interlock connections between VC-B2 devices on supply system or CS(s) are not considered.
NOTE 2 Because the source and evaluation units of the interlock signal are both on the side of the supply
system, the manufacturer of the supply system can largely define the signal waveform and quality.
5.2.2.3 Pre-charge/discharge, disconnect
An individual pre-/discharge unit and disconnecting device shall be provided per HPI.
When multiple CSs are coupled in series connection, the “predecessor CS” shall serve as PS for the
“follower CS“, and therefore a “predecessor CS” shall provide the pre-charge function.
5.3 Compatibility criteria for PS, HPI and load
5.3.1 Block diagram
The main circuit blocks in the whole system are shown in Figure 9.
Key
BC Brake chopper
CaLd cable load
CaSrc cable source
HPI high power interface
L load
S pre-/discharge unit/(dis-) connecting device
PS power source
I supply system (e.g. tractor)
II consumer system (e.g. implement)
Figure 9 — Electrical source and electrical load circuit blocks
5.3.2 Value ranges for system components:
To enable compatibility between supply system and CS, the following parameters shall be within these
value ranges:
— inverter switching frequencies: 4 kHz < f < 16 kHz
— inverter switching frequency f - 3 * f > 4 kHz (if 6-step modulation mode is
switch-source fundmax-load
used).
— low pass filter for load inverters use a cut-off frequency f ~ 2 kHz (including complete DC
cutoff_filter
harness, filter elements, and the DC link capacitor(s) on the load(s))
— PS 6-step mode is not allowed for PS (see below PSR2). The CS can use that mode. This avoids
resonance effects.
— inner source impedance 1 mΩ < R < 175 mΩ
i src
— inner source inductance L : 50 µH (for R = 1 mΩ) < L < 8 mH (for R = 175 mΩ).
i src i src i src i src
— DC link capacitance of one CS: 100 µF < C < 10 mF (approaches for a rough estimate: see
DC src/ld
Annex A)
— Y-capacitors: 100 pF< C < 1 µF (If no dedicated Y-capacitors are used, the parasitic capacitances are
y
defining the lowest capacitance values)
— contact resistance DC-contacts according to ISO 23316-2:2023 4.5.7.
— resistance of the PBC (according to ISO 16230-1: <100 mΩ between two parts with connection
through HPI included, which can be touched simultaneously by one person)
NOTE 1 In B.4 simplified electrical source and load circuit diagrams are provided, which are applicable to
various operational modes. All device values correspond to the equivalent circuit diagrams.
NOTE 2 Cable length has no critical impact regarding the system behaviour (considerations regarding cable
length, see B.1).
NOTE 3 Considerations regarding DC-Bus filters, see B.6.
5.3.3 Limitations on ripple current
Compatibility between PS and CS shall be ensured by the requirements according to Tables 2 and 3.
Table 2 — Requirements for PS (PSR)
Ref Requirement Rationale
PS Requirement 1 PS shall use an active PWM rectifier to It is required to be known if a PWM rectifier is
provide the DC bus source. in use, as it will define what current rating can
(PSR 1)
be expected in the DC capacitor bank.
PS Requirement 2 PS PWM rectifier shall not use bus clamp Use of any of these modulation methods would
modulation, over-modulation or 6 step produce low frequency current ripple on the DC
(PSR 2)
modulation. bus which can overload the load(s).
PS Requirement 3 The PS shall be able to continuously carry This level of ripple current is likely to flow in
an AC ripple current which originates in the system. It does not significantly affect the
(PSR 3)
the load(s). PS DC bus capacitor life time or temperature or
cause excessive ripple current.
Frequency band 10 Hz to 100 kHz
Low frequency filter (f< 1 kHz) would degrade
Magnitude I I =0,17 I
lf lf dc
transient performance of the dc bus voltage.
Where I is the rated dc bus current of the PS.
dc
Table 3 — Requirements for load (ELR)
Ref Requirement Rationale
Load Requirement 1 If the load uses inverters, which operate Lower power loads produce a PWM band rip-
with PWM modulation, the ripple current, ple current which is low enough to have little
(ELR 1)
which flows in the PS, shall be limited. effect on the PS.
Passive LC filters in the load may be used These CS(s) do not need a filter. CS(s), which
to reduce this current. would exceed the allowed ripple current need
to have a series inductor to limit the current.
Frequency band 1 kHz to 100 kHz
Magnitude I I =0,17 I
lf lf dc
I is the rated dc bus current of the PS.
dc
The CS shall specify minimum PS current,
which allows the operation of the CS.
Current shall be measured using test ELT1
(see below 5.3.4.2).
Load Requirement 2 If the load uses inverters, which operate Lower power load(s) produce a low frequency
with 6-step, bus clamp or over-modulation, band ripple current which is low enough to
(ELR 2)
the ripple current, which flows in the PS, have little effect on the PS from a thermal or
shall be limited. voltage ripple perspective.
Passive LC filters in the load may not be
used to reduce this current.
Frequency band 10 Hz to 1 kHz
Magnitude I I =0,17 I
lf lf dc
I is the rated dc bus current of the PS.
dc
Current shall be measured using test ELT1
(see below 5.3.4.2).
Load Requirement 3 The total ripple current limits from ELR1 The whole frequency band needs to be consid-
and ELR2 shall not be exceeded ered.
(ELR 3)
Frequency band 10 Hz to 100 kHz
Magnitude I I =0,17 I
lf lf dc
I is the rated dc bus current of the PS.
dc
Current shall be measured using test ELT1
(see 5.3.4.2).
5.3.4 Test methods
5.3.4.1 PS tests (PST)
a) Test1 (PST1): ripple voltage
Load the PS to the rated output current using a resistive load with a series inductance of > 250 µH.
Measure the ripple voltage at the PS terminals.
PS ripple voltage shall not exceed 2 % of VC-B2 DC voltage in the DC link circuit.
b) Test 2 (PST2): ripple current
Load the PS to the rated output current I (i.e. the maximum output current of the PS) using a
DCmax
resistive load with a series inductance of > 250 µH. The test is performed with 3 frequencies of the
current I :
DCmax
— Frequency 100 Hz
— Frequency 1 kHz
— Frequency 10 kHz
Allow the system to operate until an electrical and thermal steady state is reached.
The total rippl
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