Electromagnetic emissions (EME) of electric and electronic units should comply with national and international standards. Software approaches to reduce the conducted EME are preferable, since they do not require additional on-board hardware. Many techniques have been developed, with different levels of efficiency. This work aims to analyze a new software method to mitigate the conducted emissions of three phase power inverters, focusing on those used to drive brushless DC motors (BLDC). This has been done reducing the conducted EMI common mode (CM) component using software to compensate parasitic delays. The technique is verified both analytically and experimentally, and its performances have been compared to the Spread Spectrum Modulation (SSM) ones. The proposed approach shows better performances with respect to SSM below 24 MHz. The results confirm the effectiveness of the delay compensation technique in terms of CM conducted emissions reduction. Moreover, the proposed approach has no drawbacks on safety and it does not present reductions in the inverter efficiency.

This article presents the design of a new closed loop technique that reduces the common mode conducted emission. It can be applied to any kind of switching circuit in which couples of outputs are modulated by a bipolar PWM signal. It is based on the compensation of the delay between complementary output switching edges, using a simple sensing circuit and a low computational effort software algorithm, which is implemented in a microcontroller driving the switching circuit. One of the main advantages of the proposed solution is the reduction of the disturbance energy, without affecting the system efficiency. The technique is practical to implement, and the measurements performed on a power inverter prototype confirm the theoretical analysis outcomes about the reduction of the conducted emission in the lower-to-medium frequency range.

The design of the power supply electromagnetic interference filter needed to mitigate the conducted emission of electronic modules can be performed best if the magnitude of the common mode (CM) and that of the differential mode (DM) interference are known. In common test setups, the two terms can be obtained from the signals measured at the line impedance stabilization networks (LISNs) output ports using DM and CM rejection networks or through the postprocessing of the output signals in the time domain. Both these approaches rely on the perfect matching of the LISNs internal filters, which is not realistic. Indeed, the LISNs mismatch allow the DM to be measured as CM and vice versa. In this work, the influence of the LISNs mismatch on the separation of CM and DM is investigated and a fast and accurate method to do that is proposed.

With the rise of telecommunication systems in recent decades, the implications for human health have prompted a search for ways to reduce the impact of electromagnetic waves in buildings when necessary. A viable and promising solution to realize electromagnetic shielding could be the use of drywall panels coated with a biochar paste, as proposed in this study. Biochar (bio-charcoal), a low-cost and carbon-based material, can be obtained by the thermochemical conversion of different biomass sources. A commercial wood-based biochar thermally treated at 750 °C is considered in this work. Transmission coefficients of several gypsum board elements with a biochar coating are measured in the frequency K-band (18–27 GHz). In addition, the SE of a double panel configuration, obtained by joining two coated boards to form a multilayer structure, is evaluated. The results show that the biochar coating significantly enhances the SE compared to uncoated drywall. At the highest biochar loading investigated (0.20 g/cm²), the shielding effectiveness consistently exceeds 27 dB for single panels and 46 dB for double panels across the entire frequency band. These findings indicate that biochar-coated drywall systems offer a practical and sustainable solution for integrating electromagnetic shielding into building envelopes, paving the way for innovative applications in indoor exposure control.