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To satisfy the ever-increasing requirement from load side and improve the power quality through harmonic content reduction, the paralleled converters’ structure is seen to be an interesting solution. However, paralleled converters, in which the same dc and ac sides are shared, suffer from a major challenge related to the excessive circulating currents due to the difference in the induced common-mode voltage (CMV) in each converter. This voltage difference is due to the instantaneous potential difference between paralleled phase-legs, due to the discrepancy in circuit and control parameters of paralleled converters. Consequently, zero-sequence circulating current (ZSCC) as well as differential-mode circulating current (DMCC) shall appear between the paralleled converters. In this context, this article utilizes the interleaved pulsewidth modulation (PWM) concept for the ZSCC and DMCC reduction in paralleled split-source inverters (SSIs), where this SSI is a single-stage dc–ac converter and the prior mentioned operation and associated issues have not been investigated yet. This article describes the three-phase SSI structure and its basic operation, and shows the corresponding CMV waveform. Then, based on the shown analysis, an interleaved discontinuous PWM strategy is proposed to restrain the CMV amplitude and reduce the induced circulating currents. Furthermore, the effect of changing the modulation index and interleaving angle on the overall converter behavior has also been evaluated in case of using SSI. The analysis and simulations revealed the effectiveness of the proposed modulation strategy compared to counterparts. Finally, the shown simulation results are validated with an experimental prototype of 1 kW. [ABSTRACT FROM AUTHOR]

Common-mode voltage (CMV), caused by standard high-frequency pulsewidth modulated (PWM) voltage source inverters (VSIs), is a major area of interest in various applications, such as electric motor drives, transformerless photovoltaic systems, and grid-tied inverters. Since VSIs have only the buck capability during the inversion mode, an additional boosting stage either in the dc side or in the ac side has to be utilized for low-voltage-fed applications. On the other hand, single-stage solutions, with buck and boost capabilities, represent an interesting alternative with reduced cost, complexity, and converter volume. Among the possible single-stage solutions, split-source inverter (SSI), which has been recently proposed, has several merits over its counterparts. One of the questionable aspects concerning this topology is the CMV, which has not been investigated yet. This article examines the induced CMV with the SSI. This is done by examining the CMV waveforms for VSI and SSI topologies, and then, comparing each other under different PWM schemes. Furthermore, this article proposes the use of the discontinuous space vector PWM scheme with the SSI to mitigate the CMV, where the analysis shows a significant reduction in the CMV compared to the other schemes. In order to validate the introduced analysis, simulation model has been designed using MATLAB/Simulink environment, and simulation results are presented. Moreover, a prototype has been built-up for testing the proposed concepts and the obtained experimental results are provided. [ABSTRACT FROM AUTHOR]

This paper proposes a family of spread-spectrum schemes, several of which are new, for conducted-noise reduction in dc–dc converters. The schemes use three randomized parameters to generate the switching signals: carrier frequency, duty ratio, and pulse position. The increasing performance and cost reduction of field-programmable gate array (FPGA) technology have made the application of these schemes possible in this field. A theoretical framework for a general representative scheme is provided. Then, the proposed schemes are designed and implemented using an FPGA-based controller. Furthermore, the effect of using the proposed controller on common-mode, differential-mode, and total conducted-noise characteristics of the dc–dc converter is experimentally investigated. In addition, the three randomization parameters are swept to determine the values that best achieve the conducted-noise spectrum spread. All studied cases are designed, implemented, and experimentally investigated. Then, the conducted-noise spectra are compared. The experimental results show that the use of the proposed controller with the determined randomization values significantly improves the conducted-noise spectrum and effectively reduces the noise peaks at both high- and low-frequency ranges. [ABSTRACT FROM AUTHOR]