Performance Evaluation of Differential Mode Zeta Inverter using Various Modulation Schemes

Conventionally, two stages are used for DC to AC voltage conversion. In the first stage, the boost converter provides voltage gain, and the H-bridge inverter provides the DC-AC conversion in the second stage. The two-stage conversion process can be reduced to a single-stage with the help of a new breed of inverter topology, namely differential mode inverter (DMI). For the same power rating, the single-stage DMI increases the energy density and compactness of the system compared to the two-stage. In DMI, using a specific DC-DC converter module, a higher voltage gain can be obtained. In this paper, a DC-DC Zeta converter based DMI is presented. The analysis of single-phase differential mode Zeta inverter (DMZI) is carried out with two different modulation schemes, namely Continuous mode modulation scheme (CMS) and Discontinuous mode modulation scheme (DMS). The steady-state analysis is performed to investigate the eight-order system. Generalized analytical expressions are derived, which are applicable to both modulation schemes. Also, a comparative analysis is presented to compare both modulation schemes by pointing out the requirement of maximum duty cycle, the voltage stress on the semiconductor switches, and system losses. Finally, MATLAB/SIMULINK results are provided to verify the analytical expressions.