Abstract:
The thesis proposes and analyzes a control strategy for three different scheme of Buck-Boost
Inverter. Three different single-phase inverters based on two-quadrant Buck-Boost DC-DC
Converter topology were proposed and analyzed for differentially connected load with modified
delta modulation control strategy. The proposed single-phase inverter schemes were adopted for
three phase operation by connecting the two-quadrant DC-DC Buck-Boost Converter with
differentially connected load in delta or Y arrangement which were controlled by three
individual modified delta modulators for each of the phases. A modified voltage controlled
quadrature oscillator circuit was introduced and developed in order to generate and control the
reference signal of the individual delta modulator for three-phase inverter operation. The three
control signal were generated by converting the two 900 phase shifted output of the voltage
controlled quadrature oscillator into three individual 1200 phase shifted outputs by vector
addition. Delta Modulation output pulse train variation was investigated by changing different
parameters of the proposed delta modulation scheme. Three-phase Buck-Boost Inverters were
also investigated with the proposed control strategy for variable operating condition for three
different schemes with load connected in delta and Y arrangement. Received output wave-shapes
were nearly sinusoidal for a certain range of operation.
