The talkative power concept is a simultaneous power-line communication and energy transfer technique which integrates data modulation into a power converter. The information sequence is deterministically represented by the ripple, which superimposes the output voltage. With a few exceptions, so far emphasis has been on scenarios where only a single node is actively transmitting data in a certain time slot in simplex mode. In microgrid applications, however, multiple active power sources are of interest as well. Examples include battery management systems, smart metering, electricity trading systems, and smart grids with several power sources, energy storage devices, and data receivers. In this contribution, bus networking aspects based on the talkative power concept are presented for scenarios with several active nodes and for full-duplex communication. The paper addresses potential multiple access techniques as well as duplexing schemes for connected power converters supporting bidirectional power and information flow. In numerical results, a spread spectrum scheme based on orthogonal variable spreading factor codes in conjunction with frequency shift keying (FSK) is presented for four simultaneously active buck converters with a sum data rate of 500 kbps at a switching frequency of 1 MHz. In general, with 2-ary FSK, the maximum achievable sum data rate is half of the switching frequency in a synchronous setup.

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Magnetic communication is a promising technique in harsh environments, such as seawater. To enable efficient communication, transmitting and receiving coils are conventionally operated as part of resonant circuits. However, this results in narrow bandwidths and the associated disadvantages. Thus, most digital modulation schemes cannot be used efficiently on these systems. In this contribution, a mixed hardware/software approach for efficient frequency shift keying is presented. With this energy-efficient modulation concept, the full available bandwidth of a receiver can be utilized for data transmission, while all advantages of using a resonant circuit on the transmitter side can be retained. Towards this goal, a transmitter-side resonant circuit is designed, which supports discrete switching between multiple resonant frequencies. The data symbols are mapped onto these unique resonant frequencies. This prevents the parasitic amplitude modulation associated with conventional frequency shift keying applied to narrow bandwidth circuits, resulting in maximum transmitted magnitude and minimum symbol distortion without need for any further measures. Furthermore, the frequency spacing and/or the cardinality of the symbol alphabet can be increased considerably. At the receiver side, the classical pick-up coil is replaced by a highsensitivity broadband magnetic field sensor. Numerical results of the mixed hardware/software scheme are provided, and are verified by an experimental setup. This setup is constructed using principles from the field of power electronics and demonstrates, how this modulation concept can be implemented with relatively simple and highly energy efficient electronics and without the use of linear amplifiers in particular.INDEX TERMS Digital modulation, communication in harsh environments, magnetic communication, magnetic field measurement, magnetic sensors, mobile communication, resonant inverters, switched capacitor circuits, underwater communication, wireless communication.

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