Porsche reveals AC battery technology

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According to Legend, New Year’s Eve, 1899, the head of the American customs office announced: “Anything that can be invented has now been invented”. His statement missed a few things, such as space trips, nuclear weapons and internet, but he finally taught us a precious lesson in the assumption of human ingenuity has reached its limits. Take, for example, the battery systems that supply electric vehicles. The batteries store electricity as direct current (DC). This is why electric vehicles need inverters to convert the alternating current (AC) widespread in most houses and commercial buildings in DC which can then be used to recharge their batteries. But many electric motors that feed our electric vehicles operate on AC.

We assume that China is the leader in everything that has to do with battery technology, mainly because Catl and Byd are the two largest battery manufacturers in the world. It is therefore quite surprising to read in the last press release From Porsche that Porsche Engineering claims to have developed an “AC battery” for electric vehicles which combines many components in one room. It has a standardized control unit with a particularly powerful real-time computer platform. The system was developed as part of a feasibility study, but has been tested in the laboratory and demonstrated in a real vehicle.

Porsche Said that the drive system for an electric vehicle generally consists of several separate components – a high voltage battery, a battery management system, a power electronics to control the electric motor and an on -board charger for the load with AC power. In this new technology, power electronics uses an impulse inverter to convert the CC voltage of the battery to a three -phase sinusoidal alternative voltage necessary to supply the electric motor or the engines that turn the vehicle wheels.

“The trend in the automotive industry is towards highly integrated components,” explains Thomas Wenka, specialized project manager at Porsche Engineering. “This opens up new possibilities in terms of housing size, weight and cost reduction, reliability and efficiency.” Its development team has created an AC battery platform which integrates the separate functions of the battery management system, the pulse inverter, the low voltage CC and the on-board charger in a single component.

To do that, Porsche The engineering divided the high-voltage traction battery into 18 individual battery modules, distributed on three phases controlled individually by semiconductor switches. The flexible interconnection of individual battery modules in a converter parallel to several modular levels (MMSPC) allows dynamic modeling of the tension curve so that the sinusoidal three -phase random voltage for the engine can be generated directly by CC tension from the battery modules. “With the MMSPC, the direct control of the electric driving engine during driving and direct connection to the AC grid to load the battery is possible,” explains Daniel Simon, project manager at Porsche Engineering.

Other advantages include easier scalability to supply various transmission variants as well as the safer handling of current transport components during maintenance. In the event of an accident, “the MMSPC is turned off and the system effectively returns to its individual modules, which means that only the module tension can always be measured,” explains Wenka. In addition, chess protection increases in the event of a possible defect in individual battery cells because the intelligent control system bypasses the affected battery module. This makes possible a so -called gearbox function so that a partially disabled car can be carried out at the nearest repair installation, although under reduced power. With a conventional battery, such failure would result in complete ventilation of the vehicle. The AC battery platform also provides the rapid re-revision of the traction battery via a pulsed load.

Porsche shows its battery management prowess

A major challenge in the implementation of the AC battery concept was the development of a powerful and rapid central control unit which can accurately control the individual battery modules. “The dynamic reconfiguration of battery modules in the modeling of sinusoidal waves is made possible by the underlying distributed system, which must meet real-time requirements in all circumstances,” explains Simon. “After all, a delay in switching modules would cause batteries and associated power electronics.”

“The processing unit represents a heterogeneous multiproacher platform and runs as a single chip system. It combines a network of programmable doors in the field (FPGA) – an integrated circuit with programmable equipment – for data control and monitoring with regard to the real -time capacity of the system, and a powerful multicuted processor for the processing of large amounts of data in a single component component, “explains Simon.

“The FPGA can resume complex calculations to relieve the processor and complete the missing devices, which are significant advantages in terms of scalability and flexibility compared to usual pure microcontroller solutions. And by selecting the derivative within the System-On Chip family

A particular characteristic of the approach is the implementation focused on the software of the functions of the control unit. “A part runs on a processor, which uses FPGA for rapid control and optimal switching strategy, and ultimately controls all modules in a synchronous manner. This allows a dynamic reconfiguration via the software. “Using a Puce Systemon approach with a CPU and a FPGA, we allow a difficult capacity in real time that cannot be made with normal micro-controls.”

The point to take away

To be honest with you, dear readers, I have no idea what all this jargon means. This press release is obviously written by very intelligent and capable engineers, but a large part is well above my head. It is enough to say that Porsche, who has a long and proud story of excellence in genius, has designed new ways to control the many components of an electric vehicle platform. For years, we have said that it took a century to perfect the internal combustion engine, and we will probably see a similar model of constant innovation with regard to electric vehicles. The latter news from Porsche proves this point. However, it seems unlikely that most of us will be able to make the difference compared to the driver’s seat.