Electric vehicle charging according to standard IEC62196 – mode 3
This application note accompanies the Electric vehicle AC charging example. The
IEC62196 Type 2 connector is modelled. Communication between the EV charger and the EV is
performed using PWM signalization over Control Pilot as per IEC 61851-1 and J1772.
Introduction
For charging electric vehicles (EV), an exchange of information between the EV supply
equipment (EVSE) and the EV is needed in order to define conditions (e.g., charging power).
This signaling is based on the international standard IEC 62196-1 which distinguishes 4
modes: 3 for AC and one for DC charging. Figure 1 summarizes the features for these modes. IEC 62196 also defines the used
connectors dependent on their region.
Model description
Figure 2 shows the implemented model
of an EV, a charging station, the connecting cable, and the public grid. The EV battery is
modelled using Battery ESS (Generic) component.
The following section focuses on the signaling between the single components.
The connection between the EV and the charging station has been realized by a direct
connection that can be interrupted by a SCADA-controlled contactor. Figure 3 shows the signal of the pins
CP, PE, and PP. A resistor placed between PE and PP on each end of the cable codes the
maximum allowed current Imax_cable. The measurement of this resistance is included both in
the EV and in the Charging Station subsystems. Table 1 shows the cable
characteristics for the measured resistance. In order to demonstrate different cable types,
the resistor has been realized as a variable resistor.
Table 1. Coded cable characteristics of the resistor between PP and PE
Resistor PP-PE
1500Ω
680Ω
220Ω
100Ω
Maximum current
13A
20A
32A
63A
Cable cross section
1.5 mm2
2.5 mm2
6 mm2
16 mm2
After the maximum current carrying capacity of the cable is detected, the EV charging
requests need to be signalized, which is done via CP. On the CP pin the charging station
provides a pulse width modulated (PWM) signal with an amplitude of ±12 V and a frequency of
1 kHz. This is evaluated on the EV side by the circuit shown in Figure 4. When the car is connected, the
resistor R2 = 2.7 kΩ is in parallel and voltage VCP_car drops down to 8.8 V which states
that connection is properly. With a charging request, the EV closes contactor Scar, which
connects Rcon = 1.3 kΩ in parallel to R2. This reduces the VCP_car to 5.6 V and indicates
everything is set up for charging. These statuses are evaluated on the EV and the EVSE side
by a C-function Status. The maximum available current by EVSE is communicated via the Duty
Cycle (DC) of the PWM signal on CP. The EV evaluates the DC. The model realizes this in the
detect duty cycle sub model, which uses mainly edge detection and an integrator. The maximum
current Imax_DC = 0.6 DC[%] is calculated by multiplying the DC percent by 0.6. Finally, the
maximum current that can be provided by EVSE is the minimum of the two limits Imax_cable and
Imax_DC.
Table 2. HIL device resource utilization
No. of processing cores
2
Max. matrix memory utilization
12.5%
Max. time slot utilization
59.38%
Simulation step, circuit solver
1 µs
Execution rate, signal processing
Multirate (10 µs, 400 µs)
Simulation
Figure 5 shows the SCADA
representation of the previously described model. It represents settings and status of all
components. For the charging station, we can mainly set the duty cycle and observe the status
coded by Vcp. The cable allows us to connect the EV and to select a cross section of the
applied cable. For the EV a user interface like you would find in a normal car is visible. In
addition, the internal values of the charging controller are shown. These include the detected
DC, maximum current, and the detected status. The scope in the middle shows the Vcp on the EV
side, including the detected edges from duty cycle detection.
Table 3. Minimum requirements
Files
Typhoon HIL files
examples\models\automotive\electric vehicle AC charging
TyphoonTest IDE script path: examples\tests\examples\tests\108_ev_ac_charging_test\test_ev_ac_charging.py
The provided test automation script validates the performance of the EVSE during the following operation modes:
Verification of vehicle connection
EVSE Ready to supply energy
EV Ready to Accept Energy
Verification of EV current control tolerance for several duty cycles
After these operation modes have been tested, the script generates a plot of the Maximum supply
current as a function of the pilot signal duty cycle. Along this plot is a tolerance curve which
confirms that the values of the Maximum supply current are in the expected range. Both of
these curves can be seen on the right of Figure 8,
along with the list of all test cases on the left of the figure.
Figure 8. EV AC charging - Maximum supply current vs pilot signal duty cycle plot
You can obtain a full test report by running the test from TyphoonTest IDE (for easy access,
press the "Open Test" button in the Example Explorer).
Authors
This model has been created by the Fraunhofer Institute for Solare Energy Systems ISE
within the activities of the Digital Grid Lab www.digital-grid-lab.com. In this service
laboratory, tests of EVSEs are performed. For detailed questions, please refer to:
[1] Dr. Bernhard Wille-Haussmann, Fraunhofer ISE, Head of Grid Operation and Planning,
[email protected]