Switching (transformerless) DC/AC 12V/230V 150W modified sine wave inverter

The inverter is suitable for battery powering of mains appliances. It is a switching converter, which contains no bulky, heavy and expensive iron transformer. The advantage of small size and weight, precise output voltage stabilization and among other things, very little quiescent power consumption, which can not be achieved using th
Switching (transformerless) DC/AC 12V/230V 150W modified sine wave inverter - schematic

e classical transformer. The disadvantage is perhaps it is a little more complicated :). Use: Can be used for most appliances except those capacitive (eg. with high parallel capacitor) and those that require pure sine for another reason. Not suitable for capacitive limited mini fluorescent nigth lights and LED light bulbs. For the conventional fluorescent (or discharge) lights is necessary to disconnect the capacitor. Circuit Switching Inverter with modified sine wave typically consists of two parts: 1) DC/DC converter that increases the DC input voltage of 12V (24V, 48V) to the high DC voltage corresponding to about the mains voltage amplitude (for mains 230V~ it is 325V=) and 2) polarity switching bridge that turns this increased voltage into a modified sine wave. For lower output power switching converters (up to about 150W) the DC/DC converter can be built as flyback supply. For more power would be necessary to use a push-pull supply (or forward, but the complication is very high secondary voltage). Single coil step-up inverter is not suitable, because the step-up ratio is too large. Due to the low power I have my DC/DC converter finally built as flyback supply. I will omit the detailed description of the DC/DC section, because this schematic has already been described in detail here: DC/DC converter 12V / 325V 150W. The inverter bridge is composed of the transistors of MOSFET N type: T3, T4, T5 and T6. They are...

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