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Summary: Recently, a novel dual switching frequency modulation (DFM) has been proposed for impedance network inverters (INIs). The proposed approach allows the INIs to be designed optimally in size and efficiency, for motor drive applications. Moreover, DFM provides the possibility of operation with unity modulation index. However, DFM requires a high‐frequency ratio between pulse‐width modulation (PWM) and sinusoidal PWM (SPWM) switching frequencies. This paper proposes an improved modulation strategy to overcome this issue. The modulation called interharmonic dual frequency modulation (IDFM) utilizes the interharmonic areas of a conventional sinusoidal PWM to implement DFM. The proposed approach gives a low total harmonic distortion (THD) output voltage without increasing the frequency ratio of PWM and SPWM. IDFM provides the possibility of selecting a wide range of frequencies for both switching modulations. The approach is explained theoretically, compared with other switching strategies, and also the simulation and experimental results are used to validate its performance. [ABSTRACT FROM AUTHOR]

Summary: Pulse width‐amplitude modulation (PWAM) have been widely used in recent years to mitigate switching losses as well as reducing passive components' size. This paper precisely investigates this modulation approach in quasi‐Z‐source inverters (qZSI). It will be concluded that the existence of capacitive paths from load to source in such converters causes two undesired behaviors while utilizing PWAM, which increases total harmonic distortion and semiconductor stresses. Bypassing the capacitive paths is proposed in this paper to alleviate these issues. In order to implement this approach, a bidirectional quasi‐Z‐source inverter is studied. A design procedure is presented to achieve a fast dynamic response for tracking reference voltage. The operation of both conventional and bidirectional qZSI under different loads including resistive and resistive–inductive loads is investigated in the simulation and experiment. According to experimental results, by utilizing bidirectional qZSI, THD is improved from 12.34% to 3.51% for a lag load. Moreover, the voltage stress of the semiconductor no longer exists. [ABSTRACT FROM AUTHOR]

It is well‐known that the presence of non‐linear loads in the distribution system can impair the power quality. The problem becomes worse in microgrids and power electronic‐based power systems as the increasing penetration of single‐phase distributed generation may result in a more unbalanced grid voltage. Shunt active power filters (SAPFs) are used for improving the power quality and compensating for the unbalance grid voltage. This study presents a modification of the classical control structure based on the finite control set model predictive control (FCS‐MPC). The proposed control structure can retain all the advantages of FCS‐MPC, while improving the input current quality. Furthermore, a computationally efficient cost function based on only a single objective is introduced, and its effect on reducing the current ripple is demonstrated. The presented solution provides a fast response to the transients as well as compensates for the unbalanced grid voltage conditions. A straightforward single loop controller is compared to the conventional way of realising the active power filters, which is based on space vector pulse width modulation. The simulation results have been obtained from MATLAB/SIMULINK environment, while the obtained experimental results, utilising a 15 kVA power converter, highlight the effective performance of the proposed control scheme and verifies the introduced MPC‐based method as a viable control solution for SAPFs. [ABSTRACT FROM AUTHOR]