# Influence of Random Modulated Power Converter on G3 Power Line Communication
## 1 Introduction  
Modern society is becoming increasingly interconnected, and the electric power grid is providing, besides energy from the sources to the loads, a main path for communication systems. Although, in many applications, separate lines are used for power deliveryand data communication, in recent installations they have been merged by resorting to Power Line Communication (PLC) technology [1; 2; 3]. Transmitting power and data through a single interconnect is highly desirable in all those fields in which reduction of cost, mass, and weight is the target. Therefore, PLC is attracting increasing interest in different applications, e.g., Smart Grid (SG), Advanced Meter Infrastructure, home automation, and electric vehicles [4; 5; 6; 7]. G3-PLC is a widespread communication protocol in many PLC applications, such as in the SG framework. However, recent research results put in evidence that it may suffer from potential coexistence issues associated with the power converter modulation scheme being used. In particular, alternative Pulse Width Modulation (PWM) schemes such as Random Pulse Width Modulation (RPWM), which are largely adopted as a cost-effective alternative to traditional EMI filters to reduce the Conducted Emissions (CE) from power converters, have been found to interfere with the PLC [8; 9; 10; 11]. The effects of power converter modulation schemes on PLC systems are an open research area, and enough research has not yet been conducted. There are contributions discussing the comparison between conventional PWM and RPWM effects on the PLC system. For instance, in [12], the comparison between the deterministic and random modulation effects on the narrow-band G3-PLC performance in terms of Frame Error Rate (FER) is presented. In that work, only one type of RPWM scheme, i.e., Random Frequency Modulation (RFM), was considered, and it was found that the RFM results in a higher FER than the deterministic modulation in a specific switching frequency range (50-75 kHz) near the center frequency of the G3-PLC (63 kHz). In [13], the influence of deterministic and random modulation on the transmission errors of a serial communication systems is compared using a mathematical model, where no significant differences between the two modulation schemes were observed. Additionally, the influence of a random frequency modulated SiC-based buck converter on the G3-PLC Channel Capacity and Channel Capacity Loss is investigated in [14], where it is shown that RFM impairs the G3-PLC channel performance. In other contributions, the interference between randomly modulated converters and other communication protocols is studied. For instance, in [15], the effects of random frequency modulated power converters on the low frequency digital communication systems were studied, and it was proven that RPWM does not have a significant effect on digital communication systems. In general, only specific random modulation schemes (mainly RFM) were investigated in the literature, and further investigations on other random modulation strategies are required. More recently, the effects of Random Pulse Position (RPPM) on the PLC system are compared with conventional PWM in [16]. However, the analysis was carried out based on simulations only, and experimental verification is needed to draw general conclusions. Additional investigations are required to determine which random modulation scheme is most suitable for power converters in applications involving PLC. Furthermore, there are also many parameters that influence random modulation schemes, such as the switching frequency of the RPWM, the modulation index, and the Random Number Update Rate (RNUR). Hence, more analysis is required to identify constraints on these parameters, assuring coexistence with PLC. For instance, the switching frequency of the randomly modulated power converter is not constant, i.e., it depends on the specific application, and it is very difficult to draw general conclusions about coexistence by considering specific switching frequencies only.