Talkative Dual Active Bridge Converter Employing Spread Spectrum Modulation to Mitigate EM Noises

Recently, with the expansion of AC distribution systems and the development of DC Microgrids (DCMG), communication via power lines is required to check the status of the demand sides and the condition of transmission lines. In distribution systems, the conventional method using power lines requires separate signal conversion devices and does not achieve significant effectiveness due to the influence of the power lines. Therefore, talkative power converters (TPC) which use the power converter’s output voltage ripple and the PWM carrier’s variations to transmit the communication signal have been researched. However, because of EMI issues in high-speed switching converters, huge EMI filters are typically required. It can lead to challenges in communication accuracy, therefore, reducing EM noises is essential to obtain high power density and ensure accurate communication. This paper employs a spread spectrum modulation (SSM) to mitigate the EM noises of the Dual Active Bridge (DAB) converter and to embed communication data into the output voltage ripples. To demodulate transmitted data, the design parameters of the SSM are investigated for the controller design. The experimental results verify the successful transmission of the communication data through a 1-kW DAB converter prototype.