Alternating Current (AC) is the sinusoid tension with a 50 Hz frequency that is currently found in most countries, or the 60 Hz used in the US and parts of Asia. The current in a closed current circuit changes direction 50 or 60 times per second. The power grid to which our homes are connected supplies such a tension.
Direct Current (DC) always flows in the same direction. There is a polarity indicated with ‘+’ and ‘-’. Such tension is generally used in car batteries. Solar panels also supply DC tension. In order to use the latter in an AC home environment, an inverter needs to transform the DC into AC.
Other DC devices
Basically, a home’s electrical installation consists of an AC network with power sockets, lighting, etc. We are probably not fully aware of it, but we use a multitude of appliances and devices in our homes that operate on DC. For instance, several electronic devices such as mobile phones, tablets, computers, television sets, audio systems, and even LED lighting all work on DC. And let’s not forget the electric car, bike and motorcycle.
Inverters and chargers
These devices are fed via a built-in inverter (e.g. audio systems, TV, etc.) or an external inverter or charger like those used for mobile phones and similar devices. The inverter or charger transforms 230V AC tension into a lower AC tension before it is converted to DC tension used by electronic devices.
Recent European legislation has ensured that all kinds of mobile devices can be charged through a USB connection. Most switch manufacturers have welcomed this opportunity and have marketed USB power sockets. Each of these sockets has a built-in inverter behind the cover, converting 230V AC into 5V DC tension.
A home DC network
We can imagine a near future in which every new build or properly thought out renovation project will see the AC network combined with a LVDC (Low Voltage Direct Current) network. The latter could consist of multiple USB sockets that are fed through an AC/DC inverter or a DC/DC inverter. In the latter case, the solar panels and the battery storage are used as power feeds. The centrally located DC/DC inverter is only used to reduce the tension of the solar panels or batteries to a tension level that can be directly used by electronic devices. All individual transformers would therefore become superfluous.
Along with the USB sockets, LED lighting circuits can be connected to the DC network. In this case as well, individual inverters would no longer be required.
What will the future bring?
Currently, there are quite a few uncertainties complicating the prediction of the future of a home DC network. A lot could change in 10 years. For instance, well-thought products could emerge, as well as financial compensations by the government. In any case, standards for LVDC systems are already being developed.