A 12v dc/230v ac inverter/charger with advanced Protection features

Abstract

The inverter can be used as a source of ac power in the absence of grid power. The battery can also be charged by alternative sources of energy if grid power is not available at all. The unit described works as a batter}' charger when the ac mains power is available and automatically starts working as an inverter when the mains power fails. Regulation of the square wave output voltage is achieved by variation of the pulse width of the waveform. A manual switch is also provided to boost the voltage at higher loads. Protection is provided against overloading of the inverter as well as against improper or incomplete connections during charging, thereby protecting the user as well as the unit. The charging current of the battery as well as the voltage level of the battery are indicated on the front panel of the unit. The unit has worked satisfactorily on many types of loads regardless of the high harmonic content of the square wave output voltage.