۱- Introduction

۲- Proposed system

۳- Switching technique

۴- Losses calculation

۵- Simulation results

۶- Experimental results

۷- Conclusion

References

Abstract

A modified cascaded multilevel DC-AC converter using switched diodes is presented in this paper. This DC-AC converter produces great amount of voltage levels with minimized components by using hybrid modulation. It has two DC-AC converters coupled in cascade. First one is high frequency DC-AC converter and second one is low frequency DC-AC converter. The high frequency DC-AC converter is only capable to generate two levels with high frequency but the low frequency DC-AC converter is capable to produce great amount of voltage level by utilizing switched diodes. It reduces switching losses, size, cost and volume. Simulation of the circuit is done through MATLAB. The switching algorithm is realized by Spartan 6 FPGA processor board. Simulation outcomes are validated through experimental setup.

Introduction

As multi-level DC-AC converters have potential to generate waveforms with good harmonic range and voltage, they are getting increased attention. Many applications like AC power supplies, drive systems, power grid, and solar system uses multilevel DC-AC converter. The multilevel commences from three levels. Total Harmonic Distortion of the output waveform draws near to zero, if the amount of levels extent to infinity. One of the important favours of multilevel configuration is without curtailing the output power of DC-AC converter it can reduce harmonics in the output waveform. But, the issues like voltage unbalance, requirement of voltage clamping, circuit packaging and design constraints limit the attainable voltage level. Numerous traditional multilevel DC-AC converters is available out there. (i) Neutral Point Clamp (NPC) (ii) The Cascaded H-Bridge (CHB) (iii) The Flying Capacitor (FC) multilevel DC-AC converter [1]-[3]. Traditional multilevel DC-AC converters has unique demerits like high amount of switches for getting greater amount of output voltage levels that may demand excessive effort for the installation, the switching complexity, increased quantity of gate driver circuits and the size. Various multilevel DC-AC converter configurations brought together to curtail the switch count, gate drivers, dc sources and the voltage rating of the switches [4] – [۹]. Quite a few control methods studied to curtail the harmonics in output [10]. Pulse Width Modulation (PWM) is broadly in a job to regulate the DCAC converter’s output.