Porsche Engineering introduces modular EV charging technology

Porsche Engineering has developed a charging park with a new system architecture and a new generation of charging stations. This new generation of devices is characterised by impressive fast-charging technology.

It provides an attractive interface to the customer and, thanks to low operating costs, also presents a compelling business case for a wide variety of operators. The innovative charging park system designed by Porsche Engineering also provides the capability to charge the batteries of multiple electric cars at the same time.

Thanks to 800- volt technology, batteries can store enough energy for roughly 400 kilometers of range in just 20 minutes. Enough time for a coffee break at the rest stop or a few errands in the supermarket or shopping area.

The charging park system from Porsche Engineering is designed as a modular system comprised of standardised, weather-proof housings, the FlexBoxes (exterior dimensions: 120 x 120 x 130 centimetres). They enable flexible outfitting with all necessary components in a standard rack and can be positioned at quite some distance from the charging stations, for example behind a building or hedge. So both visually and in terms of noise, they are hidden from the customer.

One technical advantage for medium-sized to large charging parks is that a connection to the medium- voltage grid (up to 36 kilovolts of alternating current) exists. A transformer then converts this medium voltage into low voltage (local grid level). On the secondary side of the transformer, the same lower AC supply is always available irrespective of the location.

In addition to the lower system costs, the lower operating costs are also a substantial factor, for the Porsche Engineering charging park also functions more intelligently. The control server of the transformer station brings together all of the information from all control units of the hardware, comparable to a local network. This central brain checks and connects the control units for the cooling unit, the power electronics and the charging station. The control server also handles the communication with the back-end of the respective operator for settlement purposes. The result: Efficiency is boosted to over 95 % for the complete system, which means the possibility of significantly lower operating costs compared to systems available today.

First, the low-voltage alternating current from the transformer station is converted into direct current in the PowerBox. The PowerBox can be equipped with two sets of power electronics and supply two charging points. The system utilises silicon carbide (SiC) modules of the latest generation. The advantages compared to modules based on currently available technology consist in lower conduction, switching losses and space requirements.

Another important component of the charging park is the CoolingBox. The CoolingBox provides liquid cooling for the charging poles and power electronics. Every CoolingBox can accommodate two cooling units, each of which provides reliable cooling for multiple charging points under all operating conditions.

The Porsche Engineering development can also respond flexibly to the special requirements of charging park operators such as extremely limited space, for example at smaller locations. The ComboBox combines the PowerBox and the CoolingBox, a power unit with a cooling unit sufficient for one charging point each.

Even for cases in which no sufficiently powerful grid connection is available, the modular charging system offers a solution with which electric cars can be charged extremely fast. Specially designed for this purpose, the ChargeBox contains an additional buffer storage battery in addition to a power unit. This buffer battery is charged while no vehicle is using the charging station. Thanks to the storage battery as a replacement for grid power, the customer has access to high charging capacity at locations without medium-voltage grid connection as well. The ChargeBox is available as an entry-level model with a 70 kWh battery and a 160 kW charging station.

As flexible as the Porsche Engineering development is in terms of the individual structure of the charging park, it is every bit as flexible with regard to the charging convenience offered to the customer. The charge control unit in the station automatically establishes the communication with the vehicle. It instantaneously compares the requirements of the vehicle with the capabilities of the charging station at the beginning of the charging procedure. If a vehicle is set up for the 800-volt technology developed by Porsche, it can be charged at high power. But the charging station from Porsche Engineering also supplies vehicles designed for lower charging power levels. They, too, receive the electricity they need

Porsche employs the Combined Charging System (CCS1/CCS2) as the European standard. This is adapted to the higher voltage level and higher currents of the charging park. With minor modifications to the charge control unit, however, it is also possible to implement charging standards such as CHAdeMO or GB/T, enabling service to other vehicles even in regions as far afield as Japan and China.

Porsche Engineering team from Prague developed the software for the control of the charging park, the charging procedure and the server connection themselves. This not only makes the charging park smart-grid-capable, i.e. able to actively communicate with the infrastructure, but also makes it possible, thanks to the integrated, centralised intelligence, to continue operating even if, for example, the back-end communication to the operator's electronic payment system goes down.