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Collaborative control of microgrid clusters is challenging due to their nested control structures and the integration of heterogeneous microgrids. Besides, the wide coverage also causes some remote and sensitive industrial loads to face degraded voltage levels in the cluster system. To tackle these challenges, this work develops a novel distributed control strategy for islanded microgrid clusters. The strategy introduces tracking differentiator technology to unify different inner dynamics in heterogeneous microgrids, making them able to be coordinated in the same distributed network. Additionally, to accurately maintain the voltage level of sensitive and remote loads during distributed coordination, a containment control scheme that designs the leaders based on the running bus states of selected loads is developed. This scheme can flexibly and accurately converge the bus states of selected loads and controlled microgrids into a predefined containment range. Furthermore, to prevent instability caused by extended buffer time, a prediction-based mechanism is proposed to compensate for asynchronous delays. Finally, the effectiveness of our strategy is validated through several simulation cases and an RTLAB-based experiment.

In island microgrids, to tap the voltage control potential of different DGs, this paper presents a unified distributed cooperative voltage control approach for grid-following (GFL) and grid-forming (GFM) DGs. The proposed approach consists of a unified modeling method and a novel range-consensus-based distributed control algorithm. The modeling method employs power coupling and extended state observer (ESO) to unify different inner dynamics and control structures of DGs, making the voltage regulation of different DGs can be addressed by designing the same distributed controller. The proposed distributed algorithm introduces deviation-based states to converge the voltages to an expected range instead of a consensus state, making the algorithm is more in line with the voltage control standard of the grid code than the common state consensus ones. Besides, the local feedback designed in the algorithm improves the anti-interference ability of the system. The Lyapunov technique verifies the stability of the proposed method. Finally, the effectiveness of the proposed scheme is validated by several simulation results and a hardware-in-the-loop (HIL) test.

In island microgrids, the increasing integration of inverter-interfaced distributed generators (DGs) degrades the dynamic performance of the control system. The operation voltage and frequency may appear unacceptable overshoots and fluctuations under disturbances. To achieve rapid convergence while efficiently suppressing overshoot, this paper develops a distributed control method for island microgrids with expected dynamic performance. In addition to the typical distributed consensus design, an auxiliary dynamic reshaping function is introduced into the algorithm to increase the control degree of freedom of the operation dynamics. Thus, the proposed method can realize independent and flexible configurations of the damping ratio and natural frequency of the control system, and obtain the expected state convergence and overshoot suppression performance according to the actual requirements of microgrids. Besides, different delays between DGs are also considered. Instead of simply adopting the conventional global fixed delay time, we preserve the difference of delays to the greatest extent. Such processing can effectively reduce the conservatism of control and improve the response rate. A nonlinear programming problem is also established for DGs to calculate the allowable delays under the specific performance. Finally, several case studies and an RT-Lab experiment evaluate the effectiveness of the method.

The brake-by-wire (BBW) system is an essential part of the intelligent electric vehicle, which is determination of the braking safety and recovery efficiency. To design a safe and efficient booster motor, the design of booster motor for BBW system is discussed in this paper. Through comparative analysis, experimental simulation and assessment argument, the scheme of designing a booster motor for brake-by-wire system is completely described. First, the mainstream structure of the BBW system and the main challenges it faces in the assisted motor are discussed. Second, comparing the motors of different types and structures, the motor body and control system scheme suitable for the characteristics of the booster motor system are determined. Then, through the simulation analysis of the ansoft and matlab, the optimization scheme of the motor and performance improvement are proposed. Further, through the actual design of a set of the booster motor system, the safe and efficient motor designing are verified, and the problems involving functional safety are discussed. Finally, focus on the problem while simulation and experiment, some important countermeasures to improve current technology and prospect of in-depth study are pointed out.