Real-Time Estimation and Defense of PV Inverter Sensor Attacks With Hardware Implementation

Sensor attacks on grid-tie photovoltaic (PV) inverters can cause severe damage. Considering uncertain environments and unknown model mismatches, real-time estimation and defense for sensor attacks on actual PV inverters are challenging. In this article, we propose an optimization-driven robust estimator within the attack frequency range using the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mathcal{H}_{\boldsymbol{\infty}}$</tex-math></inline-formula> index, while the model mismatch effect on estimation is also minimized. To improve the real-time response under varying environments, an analytical solution from a convex quadratic programming reformulation is constructed. Guided by the estimation, we further develop a closed-loop compensation strategy with a tracking controller and a low-pass filter. Through code porting, our proposed defense strategy has been implemented in a microcommercial PV inverter. Hardware implementations show that our defense approach can effectively mitigate sensor attacks and maintain stable inverter operation.