The functional model for electric drives and HV systems in vehicles consists of
a drive module and an energy supply and control module. The HV system works with
an operating voltage of 96 V. It includes a complete energy supply unit with an
electronic battery management system (BMS), an integrated charger for the HV battery,
a control unit with an engine management system, all of the necessary safety components,
a Mennekes charging connection and an extra robust service disconnect. The HV battery,
with a nominal voltage of 96 V, is equipped with 32 LiFePO4/40 Ah cells. The battery
management system features a Bluetooth interface. A corresponding app (Android)
can be used to display the condition (voltage, temperature, balancing rate during
the charging process) of each individual battery cell.
The drive module consists of a complete rear-axle powertrain
with the gearbox from the Smart 450, 15 kW asynchronous motor, a control unit with
controller (E-Car-Box), DC/DC converter, fuses, contactors and control software,
and a hydraulic brake for load simulation (uphill driving).
The E-Car-Box is the core element of the drive. It houses
all key components for actuating the motor in a space-saving, secure and EMC-compliant
manner; these are cabled in accordance with the most stringent safety standards.
In addition to the air-cooled Curtis controller for actuating the motor, it also
contains the main contactor, a DC/DC converter and all necessary high- and low-voltage
Battery Management System (BMS)
The battery management system monitors
the lithium iron phosphate battery cells installed in the HV trainer and the extent
to which they are protected against overvoltage and undervoltage during the charging
process and while driving. As such, the central control unit communicates with the
connected charger and motor controller via CAN interface. The battery management
system features a Bluetooth module for communication between the BMS and a display
instrument such as a smartphone, tablet or Bluetooth-compatible Windows PC. Apps
for Windows Mobile and Android are available for download. This module enables the
state of charge of the batteries and various other parameters to be monitored.