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DC circuit breaker is the key equipment to deal with the interruption of short-circuit current. Compared with the mechanical switch, the solid circuit breaker and the hybrid circuit breaker using the semiconductor device to interrupt the short-circuit current exhibit superiorities in response duration and arc-less characteristics. Massive power devices controlled by corresponding gate drivers which make the semiconductors-based DC circuit breaker bulky and costly are required to withstand the high DC-bus voltage. In this paper, the master-slave concept-based modular circuit breaker is proposed to simplify the gate driver topology. Only one single gate driver is required to control highly compact modular sub-modules consisted of power devices, passive components, and diodes. Moreover, the proposed topology can be easily implemented with high flexibility and low cost. Specifically, the gate control function and voltage equalization for series-connected devices can be realized reliably. The master-slave concept and operation principle of the proposed topology are elaborated and the effectiveness has been demonstrated by both simulation and experimental test.

Series-cascaded Microgrids (MGs) are gaining increasing popularity because of their control flexibility and ability to synthesise high voltage levels from low power rated modules. Several control schemes have been reported for autonomous power sharing in series cascaded microgrids that incorporate dispatchable Distributed Generators (DGs) only. In contrast, this paper develops a series cascaded microgrid formed by dispatchable and non dispatchable DGs. Achieving power balance as well as voltage and frequency regulation in this microgrid configuration is a challenging task. This work proposes a decentralised master slave control scheme that regulates voltage and frequency and maintains power balance. The proposed scheme ensures maximum utilisation of non dispatchables, incorporates autonomous power curtailment under light load conditions, and offers system reliability comparable to the traditional parallel structure. The proposed microgrid configuration and control scheme are thoroughly validated via simulations and experiments under various operating scenarios.

Rate control is the most used operation method for master-slave hydraulic manipulators. However, the trajectory from the master controlled by the operator cannot completely meet the dynamic limitations and flow restriction of the hydraulic manipulator. Continuous large errors and oscillation will occur due to flow restrictions and high-order dynamics beyond the dynamic boundaries. That significantly limits the velocity tracking performance of a hydraulic manipulator. This paper proposes a flow-limited rate control scheme for the master-slave hydraulic manipulators. The variable velocity mapping is developed, adjusting the velocities to meet the pump and valves flow limits. An adaptive robust rate controller of hydraulic manipulators is designed. An adaptive boundary estimator is introduced to estimate the hydraulic manipulator acceleration boundaries, and a variable structure controller is used to plan the velocities to meet dynamic limits. The proposed control scheme was tested on a hydraulic manipulator. The results showed that the control scheme reduced velocity error and avoided the manipulator vibration, so the performance is improved for the hydraulic manipulator.

Voltage fluctuation suppression and reactive power proportional sharing in islanded microgrids (MGs) are often difficult to maintain simultaneously. Hence, a dynamical reconfigurable master–slave control architecture is proposed herein. When a load fluctuates, the leader will be dynamically selected through specific features (such as the output power, output voltage, and power capacity); subsequently, the leader sends his information to all other distributed generators (DGs) as a unified signal in the MG. Meanwhile, the other DGs adjust their local output based on the unified reference to achieve accurate power sharing in each DG. Moreover, system voltage recovery can be realized simultaneously since each DG contains closed-loop voltage control. In addition, for the automatic selection of the leader, a dynamically selected method based on a weight-voting-based differential delay method is proposed herein; the method realizes the unicity and automatic selection of the leader during communication failure. Additionally, the stability of the proposed method is proven mathematically. The results show that the proposed method is stable for any communication period and DG quantity. Furthermore, the communication delay and communication failure are derived mathematically. The results show that the proposed method demonstrates robustness against communication delay. Finally, experimental results verify the effectiveness of the proposed method under communication delays, failures, and power failures.

This study designs a high-precision bilateral teleoperation control for a dissimilar master-slave system. The proposed nonlinear control design takes advantage of a novel subsystem-dynamics-based control method that allows designing of individual (decentralized) model-based controllers for the manipulators locally at the subsystem level. Very importantly, a dynamic model of the human operator is incorporated into the control of the master manipulator. The individual controllers for the dissimilar master and slave manipulators are connected in a specific communication channel for the bilateral teleoperation to function. Stability of the overall control design is rigorously guaranteed with arbitrary time delays. Novel features of this study include the completely force-sensor-less design for the teleoperation system with a solution for a uniquely introduced computational algebraic loop, a method of estimating the exogenous operating force of an operator, and the use of a commercial haptic manipulator. Most importantly, we conduct experiments on a dissimilar system in 2 degrees of freedom (DOF). As an illustration of the performance of the proposed system, a force scaling factor of up to 800 and position scaling factor of up to 4 was used in the experiments. The experimental results show an exceptional tracking performance, verifying the real-world performance of the proposed concept., 31 pages, 9 figures

All-optical universal JK flip-flop (FF) is designed and demonstrated using ripple ring resonator (RRR). Four InGaAsP-InP optical microring resonators (OMRRs) are used to design the proposed JK FF test bed. Master-slave configuration for the same is also presented to overcome race-around condition. The system performance is analysed over different quality metrics. Two-bit synchronous up-counter is discussed as an application of presented JK FF. The test bed is compact and feasible to integrate as a photonic chip. Different sequential logic circuits can be designed with the help of presented low dimension, high speed all-optical RRR based JK FF.