An Analysis on the Optimization of Closed-Loop Detection Method for Optical Voltage Sensor Based on Pockels Effect

In engineering practice, the closed-loop optical voltage sensor (OVS) based on Pockels effect cannot reach the required precision level mainly due to the various disturbance and noise of system, so the application of OVS for low voltage measurement is restricted. Considering the cross coupling of the main and second closed-loops, the model of disturbance and noise of system that adopts the four-state modulation method is analyzed in the main closed-loop ofOVS. Based on the established noise-perturbed stochastic model of OVS, we design a closed-loop detection algorithm for the OVS system to guarantee the mean-square exponential stability with a prescribed H-infinity performance in order to optimize the detection precision of OVS. The experimental results show that the detection precision of OVS is 0.144 V while the relative measurement error of the scale factor is within +/- 0.15% in measuring low AC voltages from 140 to 500 V, which verifies the effectiveness of the proposed detection scheme.