Abstract
In the permanent magnet synchronous generator (PMSG), the DC bus voltage fluctuates up and down under the influence of the load and power grid, which greatly affects the safe and reliable work of PMSG. In order to suppress the wide range fluctuation of DC bus voltage under disturbance and enhance its anti-disturbance performance, an optimized DC bus voltage control strategy is proposed by using the improved linear active disturbance rejection control (LADRC) in the voltage outer loop. By considering factors, such as load disturbance and grid voltage mutation as the total disturbance of the system, the improved reduced-order linear expansion state observer (RLSEO) is used to estimate and compensate the total disturbance, which greatly improves the stability of DC bus voltage. Firstly, the mathematical model of grid-side converter is established. On this basis, the LADRC control based on RLESO is designed, which reduces the phase lag of the linear extended state observer (LESO) and enhances the disturbance observation accuracy of the system. Then, a lead lag correction link is added to the total disturbance channel of RLESO to reduce the noise amplification effect of RLESO. Finally, the frequency domain characteristic analysis and stability proof of the improved LADRC control strategy are carried out. The simulation results show that the control strategy proposed in the article has a better control effect on the DC bus voltage.
Highlights
A permanent magnet synchronous generator (PMSG) has the characteristics of a simple structure, low maintenance cost, low noise, and flexible operation control, which has attracted more and more attention of researchers both domestic and foreign [1,2]
linear active disturbance rejection control (LADRC) based on reduced-order linear extended state observer (RLESO), the gain of the system in the middle and low frequencies is reduced after adding the correction link, and the anti-disturbance performance of the improved LADRC in the middleand low-frequency band is enhanced
LADRC is about 0.99~1.0099 p.u., and that of the improved LADRC is close to 0.9932~1.0078 p.u.; at the moment of fault recovery, the overshoot amplitude of the DC link voltage controlled by the conventional LADRC is about 0.0245 p.u., and that of the improved LADRC is close to 0.0194 p.u
Summary
A permanent magnet synchronous generator (PMSG) has the characteristics of a simple structure, low maintenance cost, low noise, and flexible operation control, which has attracted more and more attention of researchers both domestic and foreign [1,2]. Adopting a more effective control strategy to suppress the DC bus voltage fluctuation is the key to ensure that PMSG has better performance indicators [8]. There are many control methods that can be used to enhance the transient performance of the DC bus voltage of the grid-side converter to resist sudden change of the grid voltage and load disturbance. The authors of [11] adopt master-slave control to ensure the power balance of the converters at both ends of DC bus This modified method can enhance the stability of the DC link voltage in the case of a power network voltage disturbance. The simulation verifies that the modified LADRC control strategy can ensure that the DC bus voltage has a better control effect under a low-voltage ride through (LVRT) faults
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