Today's transformers are single function devices. They change the voltage from one level to another, such as from high voltage to low voltage, which is the household distribution level of 120V or 240V. The new solid-state transformer is much more flexible. They use transistors and diodes, as well as other semiconductor based devices, unlike the transistors used in computer chips, which are designed to handle high power levels and very fast switching. Based on signals from utility companies or households, they can change the voltage and other characteristics of the electricity they produce. They can output AC or DC power, or incorporate AC and DC power into wind turbines and solar panels, and change frequency and voltage to meet the needs of the power grid. They have processors and built-in communication hardware that can connect utility operators, as well as other smart transformers and consumers.
Due to the communication and processing capabilities of this transformer, if several neighbors connect to their own cars while charging, the transformer can prevent circuit overload because it can slow down or delay charging, depending on consumer preferences and price signals from utility agencies. The same equipment can also be used to transmit direct current, that is, from solar panels to the power grid, which eliminates some devices that are currently used to convert the power of solar panels and eliminate voltage fluctuations. Failure to eliminate these fluctuations may cause the panels to disconnect and stop generating electricity.
This device is very flexible, and researchers are still studying how to best use it. There are several possibilities. Today, charging an electric car at home takes many hours, even if a dedicated charger is plugged in and equipped with a 220/240 volt circuit instead of the more common 110/120 volt socket, it is slow. Charging with a DC charger can save time by fully charging a 24 kilowatt hour battery, just like the batteries in the new Nissan Leaf, which can be reduced from 8 hours to 30 minutes. However, they are not efficient and waste about 10% to 12% of the electricity, which is the amount of electricity charged. New transformers can replace these specialized chargers, and they are more efficient, wasting only about 4% of electricity, "said Arindam Maitra, a senior project manager at the Electric Power Science Research Institute, which is developing smart transformers.
Power users, such as large warehouse supermarkets, are starting to install more solar panels and energy storage devices, so smart transformers are crucial because the electricity to be integrated comes from these sources and the power grid, Metra said. Storage systems and distributed energy can allow stores to decide when to take electricity from the grid and when to send it to the grid, depending on the electricity price at a specific time. Smart transformers can coordinate this rapid change in voltage, shifting from buying electricity to selling electricity, while maintaining grid stability and preventing neighboring lights from dimming. They can even make people buy electricity from their neighbors, Alex Huang said. If you plug in an electric vehicle to charge at night, you can negotiate with some neighbors when charging, if they have extra electricity, "he said. You can actually pay your neighbors.