Электронный каталог

Статья

Vybornov, A.
Enhancement of RF Field Stability in an LLRF System Via Inclusion of a Second-Order Integral Term in the PID Controller Transfer Function / A.Vybornov, A.Trofimov, S.Pashhenko, A.Krylov, A.Shishkin, O.De-Monderik. – Текст : электронный // Информатика и автоматизация. – 2026. – Т. 25, № 4. – P. 1283-1306. – URL: https://doi.org/10.15622/ia.25.4.11. – Bibliogr.: 22.

The paper addresses the problem of improving the amplitude and phase stabilization accuracy of the high-frequency field in low-level radio frequency (LLRF) control systems for charged particle accelerators. It is shown that low-frequency disturbances caused by power supply ripple, thermal drifts, and load variations are the dominant sources of stability degradation. It is demonstrated that the classical PID controller structure is fundamentally limited in suppressing such disturbances due to the trade-off between low-frequency gain and stability margins. A modified controller structure with a second-order integral component is proposed. The proposed approach increases the system astatism order and provides -40 dB/decade slope of the amplitude response in the low-frequency region, resulting in significantly enhanced suppression of quasi-static and slowly varying disturbances. A mathematical model of the control system is developed to capture the essential dynamic behavior of the RF chain. In addition, a nonlinear control strategy is introduced based on delayed activation of the second-order integral component, which prevents an increase in the transient duration while preserving disturbance rejection performance. Simulation and experimental results demonstrate that the proposed controller achieves more than 20 dB improvement in dynamic range and amplitude stability compared to typical modern systems, along with at least a tenfold reduction in phase root-mean-square deviation. These results confirm that introducing a second-order integral component into the controller structure is an effective method for enhancing RF signal stabilization accuracy while maintaining system stability and robustness



Спец.(статьи,препринты) = Ц 701 - Теоретические основы радиотехники
ОИЯИ = ОИЯИ (JINR)2026