inverter - Inverters World

WHAT IS AN INVERTER?

An inverter is an electronic device which converts DC voltage, almost always from batteries, into standard household AC voltage so that it is able to be used by common appliances. In short, an inverter converts direct current into alternating current.

Direct current is used in many of the small electrical equipment such as solar power systems, since solar cells is only able to produce DC.

They are also used in places where a small amount of voltage is to be used or produced such as power batteries which produce only DC. Other than these fuel cells and other power sources also produce DC.

THE OPERATIONS OF AN INVERTER

The basic circuits include an oscillator, control circuit, drive circuit for the power devices, switching devices, and a transformer.

The conversion of DC to alternating voltage is achieved by converting energy stored in the DC source such as the battery, or from a rectifier output, into an alternating voltage. This is done using switching devices which are continuously turned on and off, and then stepping up using the transformer. Although there are some configurations which do not use a transformer, these are not widely used.

The DC input voltage is switched on and off by the power devices such as power transistors and the pulses fed to the primary side of the transformer. The varying voltage in the primary induces an alternating voltage at secondary winding. The transformer also works as an amplifier where it increases the output voltage at a ratio determined by the turn’s ratio. In most cases the output voltage is raised from the standard 12 volts supplied by the batteries to either 120 Volts or 240 volts AC.

The three commonly used Inverter output stages are, a push-pull with centre tap transformer, push-pull half-bridge, or push-pull full bridge. The push pull with centre tap is most popular due to its simplicity and, guaranteed results; however, it uses a heavier transformer and has a lower efficiency.