Zero-Additional-Hardware Power Line Communication for DC–DC Converters

Abstract

A Power Line Communication (PLC) solution to provide a data link between two or more DC-DC power converters is proposed. The approach does not require additional analog circuitry or high-sample-rate analog-to-digital converters to be added on top of the original system. A modulation and signal injection method for the transmitter, and a sampling and demodulation strategy for the receiver are developed. The PLC frequency band is placed between the control loop cut-off frequency and the power electronics circuit cut-off frequency, in a region that we identify as the 'intermediate frequency band'. The transmitter modulates the converter voltage or current output by injecting perturbations into the control loop at the input to the PWM unit. To tolerate unsynchronized transmitter and receiver clocks, a virtual zero-crossing location algorithm is combined with long/short pulse identification to achieve demodulation at the receiver. The solution is verified experimentally and achieves reliable bidirectional PLC communication at 2 kbps with an 8 kHz receiver sampling frequency.Index Terms-Zero-additional-hardware PLC, Virtual zerocrossing, Long/short pulses identification I. INTRODUCTIONP OWER electronic converters and communication links are key elements of microgrids, smart grids and the Internet of Things (IoT) [1], [2]. Power electronic converters underpin low-level operation (e.g. power transmission, stability) and communication underpins high-level system operation (e.g. dispatch, balancing, metering) [3]. Conventional communication techniques, such as field bus or CAN bus, need extra cables beyond the power cable itself and so imply additional installation cost. Wireless communication, such as Zigbee and LoRa, avoid extra cables, but wireless solutions are vulnerable to interference and congestion, and require an antenna. In contrast, Power Line Communication (PLC) [4] uses the electrical power cable as the channel for data transmission and is therefore potentially an attractive low-cost solution. However, conventional PLC solutions need transmitter and receiver circuitries to achieve modulation and demodulation which increases system complexity and cost.The overlap between the operating principles of power converter control and PLC [5] has been investigated previously. Papers [6]-[9] modulate the converter by changing the switching frequency or phase to create the PLC signal (Frequency

Efficient Talkative Power Conversion With Quasi-Square-Wave Zero-Voltage Switching Hysteretic Current Control

“…Surely the computational effort is increased compared to a classical converters, but data transmission is provided simultaneously. The complexity is significantly less than in conventional PLC modems [3].…”

“…T ALKATIVE power conversion (TPC), the simultaneous transmission of power and information using a switchedmode power converter by embedding information into the switching ripple [1], [2], is possible without additional hardware effort (e.g. zero-additional-hardware power line communication [3]). TPC is applicable both in wired systems as well as in wireless system.…”

Overview of Talkative Power Conversion Technologies

“…power conversion stage, it is referred as Talkative Power Conversion (TPC) in this paper. TPC has been called zero-additional-hardware PLC in [9]. Other researchers have called it from the signal perspective such as Power & Signal Multiplex Transmission (P&SMT) [10], Power and Signal Synchronous Transmission (PSST) [3], and Power/Signal Dual Modulation (PSDM) [11], [12].…”