The objective of the present work is to improve the output waveform of three level inverters used in high-power applications, where the switching frequency is very low. This is achieved by maintaining the synchronization, half-wave symmetry, quarter-wave symmetry, and three-phase symmetry in the pulsewidth modulation (PWM) waveforms. The principles of achieving synchronization and symmetries in terms of space vectors for three level inverters are presented. A novel synchronized space vector pulsewidth modulation (SVPWM) algorithms is proposed and verified experimentally. The experimental waveforms of the inverter output voltage and motor no load current for different operating conditions of the drive are presented. The performance measure in terms of the weighted total harmonic distortion (THD) of the line voltage is computed for the linear modulation region of the drive for the proposed algorithm and compared with that of synchronized SVPWM and synchronized sine-triangle pulsewidth modulation (SPWM) technique. The comparative results show that consideration of synchronization and symmetry results in improved THD. Another significant feature of the proposed algorithm is that the symmetry and synchronization leads to self-balancing of the direct current (dc) bus capacitor voltages over every one third cycle of the fundamental.

High voltage gain DC-DC converter is a prime requirement for renewable applications, in particular for PV. Though numerous DC-DC converter is available for increasing the voltage gain, the passive elements requirement is higher which reduces the compactness, consequently, increases the cost of the system. To address this issue, a high gain DC-DC converter is reported recently. However, the number of passive elements is quite high which increases the size. To reduce the number of passive elements and maintain the same number of semiconductor devices, in this paper, a new switched inductor arrangement is proposed which is named as switched inductor double switch DC-DC converter (SL-DS-DC). Moreover, the proposed converter has a higher gain as compared to the recently reported converter. The proposed converter is analyzed in steady state and a comparative analysis is presented to prove the suitability. Finally, the proposed converter is validated experimentally. INDEX TERMS High voltage gain, non isolated, DC-DC converter, switched inductor, CCM.

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Multilevel inverters are being preferred over conventional two-level voltage source inverters in medium-voltage high-power applications. The cascaded H-bridge configuration of multilevel inverters is widely used because of its ability to generate near sinusoidal output waveforms, modular structure, simple power circuit and high reliability. The cascaded H-bridge inverter is an ideal choice for systems where isolated DC sources are readily available. The objective of this study is to extend the attractive features of the cascaded H-bridge voltage source invertes (VSI) to low-voltage and low-power applications. The details of the design of a power supply for distribution voltage levels are presented. The design is verified through simulation and experiments. A laboratory prototype of a 15-level MOSFET-based cascaded H-bridge inverter is designed and the experimental results are presented. The proposed inverter configuration is capable of generating low distortion, near-sinusoid stepped output voltage even with fundamental frequency switching. The total harmonic distortion (THD), switching losses, fault-tolerant feature of the proposed multilevel inverter-based power supply is compared with that of the conventional two-level inverter-based power supplies. The comparative results demonstrate the advantages of the proposed system over the conventional system.