To protect the climate, it is imperative to reduce greenhouse gas emissions. Electrical mobility, among other things, plays an important role in reducing these emissions. The growing number of electric vehicles is closely related to the infrastructure of charging stations: the more electric cars are on the road, the more charging points provide, and the better the infrastructure, in turn, gives an incentive for some people to do so. Switch to an electric car. Moreover, the growth in electric mobility is leading to the development of new and more powerful batteries, which reduces the cost of batteries and makes it possible to build vehicles of greater capacity and range. To develop batteries with higher energy density, higher charging capacity is necessary, especially if a large number of vehicles will be charged simultaneously in one place. For this reason, new shipping concepts are being developed. However, especially in cities and urban areas, the increasing number of electric vehicles and charging stations is a burden on the stability of the electricity grid. Concepts are therefore essential to ensuring continued stability. For example, smart and networked charging points are suitable for preventing fluctuations by helping to optimize and centrally manage charging. With two-way charging, the electric vehicle battery can also be converted into a buffer for private homes, industrial buildings and the power grid. Different charging concepts About 60% of all European EV users have their own charging stations. These charging points typically operate on AC basis, with a power output between 3.7 kW and 11 kW; In rare cases, 22 kW. Accordingly, it takes several hours to fully charge the battery of an electric vehicle. However, to use these terminals, the electric vehicle needs a built-in on-board charger (OBC). AC charging stations are also used in public parking lots or malls. Often this type of AC charging station has an output power of 22 kW. Therefore, the charging time of a 100 kWh battery is around five hours, depending on the charging power of the OBC. If your battery needs to be recharged quickly, the fast charging poles are the right way to go. It has high power ratings, between 50 and 350 kW, and is mainly used in public parking lots and large charging stations. Depending on the size of the battery, it takes less than 1 hour to charge an electric vehicle with fast charging stations; With super-fast charging stations, the time is reduced to 20 minutes. Unlike the alternating current version, the DC charging station has an integrated transformer that converts the alternating current from mains into direct current. This allows electricity to be fed into the car battery directly. Even private homes and businesses can benefit from fixed charging points with direct current. An alternative to your four walls, for example, DC wallbox (Fig.1), with an output of 22 kW. DC wall box can be easily installed in your garage, as it is easily integrated with a photovoltaic (PV) power system. Photovoltaic systems generate direct current that can be charged directly into the vehicle battery via DC / DC converters. Additionally, an Energy Storage System (ESS) can be installed to allow the excess energy to be used. In combination with the charging station, electric vehicle, hybrid and photovoltaic system, the storage system forms a standalone system that allows optimization of energy demand and generation. ESS is also ideal for recycling old batteries from electric vehicles. Although they are no longer suitable as vehicle energy storage devices, with a capacity between 70% and 80%, they can be used for less demanding applications, such as ESS. These so-called “second life batteries” (SLBs) provide the charging station with a flexible power flow, enabling an active two-way energy exchange with the power grid. As a result, electric vehicles can be used to control the load, which improves the load on the network. In the event of a shortage, the stored energy in the car battery flows backward and stabilizes the grid (V2G). DC requirements To some extent, user behavior is of great importance for developing charging concepts. Ultimately, it is up to the OEMs whether DC charging stations will be widely accepted in private homes. The critical factor is OBC, which must be integrated into every charging vehicle with AC charging stations. Since the space and energy density of the components used in a vehicle have technical limits, the charging capacity of OBC is limited. When charging with direct current, the transformer is not integrated into the electric vehicle but directly into the charging station, so the components can be saved in building the EV and the production price is reduced. At the same time, there is more space available that can be used to make the car itself more efficient. Ultimately, the savings in vehicle weight also means savings in energy, which in turn provides a potential range extension. A higher energy density is achieved by selecting appropriate structures and components appropriate to the power level. Due to its price-performance ratio, silicon IGBTs dominate electric mobility today. The cost of SiC MOSFETs can be offset at the system level by savings in other components because transformers based on SiC MOSFETs can operate at a higher switching frequency than transformers containing silicon IGBT. Moreover, SiC has excellent physical properties, such as minimal increase in forward resistance. This allows for a smaller package size and more energy saving than silicon components. SiC based components can operate at higher ambient temperatures and achieve a very high degree of efficiency. Charging stations can also be equipped with SiC MOSFETs in various styles. Rohm has already implemented this in series production. Visit EE Times Europe’s sister site to read the rest of this article. .
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