A Differential Inverter using Buck Converters
Differential inverters are DC-AC bi-directional converters that are capable of stepping up/down and inverting the DC voltage in a single-stage. Single-stage conversion results in a more compact design, higher power density and lower cost compared to two-stage conversion. A differential inverter mainly consists of two converters. It can be buck, boost or buck-boost, according to the output requirements. Controlling of the two converters is done such that difference between their output results in an A.C voltage of required frequency. Here a differential inverter using buck converters is discussed. AC output voltage of required frequency with output voltage less than or equal to input voltage can be obtained by using this converter. The construction and controlling of this converter is very simple, which is one of the main advantages of this type of converter. Switching pulses to the converters are generated by using a control voltage which has frequency same as that of output. Two control voltages are needed which will be phase shifted by 180 resulting in 180 phase shift between the output of the two converters. As the name indicates final output is the difference of two converters. Also the magnitude of the output voltage below any input voltage value can be obtained by varying the magnitude of the control voltage.