Impact of Talkative Power Conversion on PR-Controlled Single-Phase Inverters and an Adaptive Compensation Approach

In an AC microgrid (ACMG), inverters are increasingly assuming responsibilities for power conversion and low-speed communication. The Talkative Power Conversion (TPC) technique suggests transmitting information using power modulation ripple. This study employs the frequency-keyed Power-and-Signal Dual Modulation-Encoded Control Ripple (PSDM-ECR) system for data transmission. The slight variation of the ADC sampling period $T_{s}$ within the range of 8 to $14 \mu \mathrm{~s}$ caused by the frequency jumps of the ripple disrupts the assumption of a constant $T_{\mathrm{s}}$ in the discretization process of the Proportional-Resonant (PR) controller. This results in a shift in the resonant center and a discrepancy in peak gain, ultimately resulting in output voltage peak clipping and an escalation in Total Harmonic Distortion (THD). This study initially develops the analytical effect of $T_{s}$ variation on the PR coefficients, grounded in the operational principle of the TPC single-phase inverter. A second-order-generalized-integrator (SOGI) based online adaptive compensation algorithm is introduced to resolve this issue. A single-phase inverter power stage model is constructed in PLECS, and the effects of power modulation are quantitatively assessed by varying $T_{\mathrm{s}}$. The findings indicate that as $T_{\mathrm{s}}$ deviates, THD escalates from $0.003 \%$ to $3.1 \%$. Then THD is reinstated to 0.1% after compensation.