Search results for "modulation techniques"
showing 7 items of 7 documents
Experimental Validation of Maximum Constant Boost Control and Switching Frequency Optimal for three-phase Quasi-Z-Source Converters
2020
This paper presents a modified modulation scheme for quasi-Z-Source converters, based on the Maximum Constant Boost Control (MCBC) concept and Switching Frequency Optimal (SFO) as reference signal. The effectiveness of the proposed technique is validated by comparing the obtained results (in terms of AC harmonic content and voltage stress) with those carried out from traditional modulation schemes. For this reason, a test bench has been assembled and the benefits of the SFO MCBC modulation scheme have been valuated.
Performance Comparison of modified modulation Techniques for Quasi-Z-Source Converters
2020
The single-stage converters represent an innovation in the field of power electronics thanks their features. Aim of this work consists in the improvement of the performances of quasi-Z-Source converters by adopting a modified modulation technique, which is based on the Maximum Constant Boost Control (MCBC) and Switching Frequency Optimal (SFO). The results in terms of voltage stress and harmonic content are compared with those obtained with conventional techniques, demonstrating the effectiveness of the proposed modulation scheme.
Innovative Computational Approach to Harmonic Mitigation for Seven-level Cascaded H-Bridge Inverters
2020
Low frequency modulation strategies are a good solution to increase the energy conversion efficiency in high power applications. The paper is devoted to presents an innovative way to low order harmonics mitigation for seven-level Cascaded H-Bridge Inverters. In particular, this approach is based on the mitigation of selected harmonics without solve non-linear equations for an extended range of the fundamental amplitude. In fact, in real-Time operation to evaluate the control angles the polynomial equations have been identified. Through circuit simulation analysis in MatLab/PLECS environment, the effectiveness of the harmonic mitigation method has been tested and compared with theoretical re…
Modified Modulation Techniques for Quasi-Z-Source Cascaded H-Bridge Inverters
2018
Quasi-Z-source cascaded H-bridge (q Z S - C H B) inverters are one promising solution for high power photovoltaic (PV) systems. This type of topologies inherits the advantages of cascaded converters (i.e., multilevel outputs) and impedance-source inverters (i.e., high conversion ratios). In addition, it allows increasing the inverter reliability (with high redundancy). However, the modulation and control of qZS-CHB inverters are challenging to a certain extent. Thus, this paper proposes modified modulation techniques to increase the performances of qZS-CHB converters in terms of voltage gains and stresses. The novelty lies in the use of the switching frequency optimal as reference signals i…
Enhanced modulation strategy for 7-level voltage waveform in asymmetrical 5-level Cascaded H-Bridge Inverters
2022
The CHBMI performance optimization can be reached both with hardware and software solutions. Generally, asymmetrical configurations allow the extension of the voltage levels number and the implementation of an innovative modulation strategy allows for improving the performance in terms of harmonic distortion and conversion efficiency. This work is devoted to the development of a modulation strategy that allows improving the performance of an asymmetrical single-phase five-level Cascaded H-Bridge Inverter generating a 7-level voltage waveform. Thus, a digital approach and corresponding digital functions are presented. Subsequently, the impact of the dead time and the influence on the voltage…
Experimental Evaluation of the Performance of a Three-Phase Five-Level Cascaded H-Bridge Inverter by Means FPGA-Based Control Board for Grid Connecte…
2018
Over the last decades, plants devoted to the generation of green energy significantly increased their number, together with the demand of same electrical energy, also stored in battery systems. This fact produced the growth of energy conversion systems with advanced performances with respect to the traditional ones. In this circumstance, multilevel converters play a significant role for their great advantages in performances, flexibility, fault-tolerability, employment of renewable energy sources and storage systems and finally yet importantly reduced filter requirements. In this context, this paper faces the performance of a cascaded H-bridge 5 level inverter in terms of harmonic distortio…
Performance Evaluation of a Three- Phase Five-Level Quasi-Z-Source Cascaded H-Bridge for Grid-Connected Applications
2018
In the field of the PV generation, Quasi-Z-source cascaded H-bridge (qZS-CHB) inverters are promising due to their features of modularity and high voltage conversion ratio. Thus, new topology structures and innovative modulation techniques are continuously being developed to improve the performance in terms of voltage stress and harmonic content. This paper proposes an innovative modulation technique that allows reducing the voltage stress and a specially designed grid-connected control strategy is also introduced. Through simulations in MATLAB, it has been validated that the performance of a three-phase five-level qZS-CHB is improved with the proposed solution.