| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 734564 | Optics & Laser Technology | 2013 | 7 Pages |
The accuracy and scale factor of the optical voltage sensor are considerably affected by the gain drift of the phase modulator induced by temperature fluctuation. In this paper, we present a tracking system for the gain drift of the phase modulator based on four-state modulation which provides a significant improvement in the performance of the optical voltage sensor. We analyze the influence of the main closed-loop error of optical voltage sensor on the tracking system. The analysis results indicate that the main closed-loop error causes uncertain parameter and external disturbance for the tracking system. Then the model of the tracking system for the gain of the phase modulator is transformed into a dynamic system with uncertainty and stochastic disturbance by substitution of variable. The tracking system is accurately designed considering the main closed-loop error. To insure the tracking system achieves good transient performance, the closed-loop poles of the tracking system are constrained to locate in a desired circular region, while the gain error is mean-square exponentially stable via the robust control. The experiments show that the tracking system realizes precise compensation for the gain drift of the phase modulator.
► The influence of the main closed-loop error on the tracking system is analyzed. ► We establish the model of the tracking system with uncertainty and stochastic disturbance. ► The tracking system is designed to tracking the gain of the phase modulator precisely by close-loop poles assignment. ► A robust tracking algorithm for the tracking system is designed to compensate the gain drift of the phase modulator in real time. ► The OVS using the designed tracking system is robust against the gain drift caused by temperature fluctuation.
