In this paper, the output consensus problem of DC microgrids with dynamic event-triggered control scheme is investigated. According to the properties of DC microgrids and multi-agent systems, the multi-agent systems function model for DC microgrids is provided. For making the multi-agent systems achieve output consensus, the non-periodic and periodic dynamic event-triggered control schemes are provided, respectively, which are classified according to the style of receiving information. By using a series of analysis, it can be proved that these two control schemes not only can make systems achieve output consensus, but also can avoid the Zeno-behavior successfully. Moreover, the periodic dynamic event-triggered control scheme does not need the continuous information transfer. Finally, a numerical example is provided to support our conclusions.

Springback has an important influence on the forming quality of thin-walled stainless bellows hydroforming. By developing a FE model, the stress distribution is investigated and springback characteristics of two specification bellows are addressed. The results show that: (1) For tube Φ26×0.5, the maximum circumferential tensile/compressive stresses decrease by 32% and 29.1% after springback, respectively. The maximum longitudinal tensile/compressive stresses decrease by 51.8% and 39.6%, respectively. (2) Three indices are proposed to describe the bellow profile change after springback, namely, radial displacement of crown point; axial displacement of inner point; maximum convolution width. (3) For tube Φ26×0.1, after springback, the inward shrinkage of crown point increases by 0.7%, the bellow axial elongation is 0.76mm, the maximum convolution width increases by 30.3%.

In order to solve the problem that the dynamic decoupling performance of the traditional decoupling method is reduced due to the parameter disturbance of permanent magnet synchronous motor (PMSM), a composite decoupling control method based on extended state observer (ESO) is proposed in this paper. In this method, voltage drop across stator resistance, cross coupling terms, internal uncertains and external load torque are taken as disturbances. The disturbance is observed in real time by using the extended state observer and compensated to the output end of the current controller, so as to realize the current decoupling control of the system and achieve the purpose of precise control of the current loop. The results of theoretical analysis show and simulation show that the composite decoupling control strategy based on extended state observer has better dynamic decoupling effect.

In order to solve the problem that the traditional uncertainty and disturbance estimator (UDE) control needs to increase the filter order to keep good performance when facing rapid disturbance changes, thus lead to cost increase in implementing the system, a speed control strategy of permanent magnet synchronous motor (PMSM) driver based on reduced order observer compensation is proposed. The designed control strategy is robust to the system with internal parameter variation and external torque disturbance. Through the compensation of load torque, the pressure of UDE controller is relieved, and then the tracking error of high-frequency component in load torque is eliminated, and the control performance of the system is improved more effectively. This paper proves the superiority of the new compound controller through comparison of simulation. results