Networked switched systems (NSSs) have unique advantages, but the unreliability of networks, such as suffering from attacks, will reduce system performance. Besides, the required control energy to stabilize systems is not considered in existing switching signal design methods, which is worthy of improvement. In this paper, an energy function‐based resilient triggered switching law (EFB‐RTSL) is proposed for NSSs under dual‐ended denial‐of‐service (DoS) attacks and asynchronous switching. For the data communication under DoS attacks, a resilient switch‐triggering mechanism is designed that aims at reducing the unnecessary data transmission and the risk of switching signal being attacked. For the discontinuity of switching signal induced by DoS attacks, a combined structure of attacks‐triggered decision switch and buffer is constructed. Moreover, an integrated model is built to characterize the dual‐ended DoS attacks, and the maximum tolerance is given. The coupling between DoS attacking, synchronous, and asynchronous switching is clarified, which provides convenient conditions for stability analysis. Subsequently, the gains of subcontrollers are computed by a dynamic iterative algorithm. By utilizing the average dwell time and Lyapunov–Krasovskii functional technique, sufficient criteria are derived to ensure the stability of triggered NSSs when suffering from dual‐ended DoS attacks. At last, the effectiveness of proposed method is verified by a numerical simulation.
This paper introduces a new rotor design for the easy insertion and removal of rotor windings. The shape of the rotor is optimized based on a surrogate method in order to achieve low power loss under the maximum power output. The synchronous machine with the new rotor is evaluated in 2-D finite element software and validated by experiments. This rotor shows great potential for reducing the maintenance and repair costs of synchronous machines, making it particularly suited for low-cost mass production markets including gen-sets, steam turbines, wind power generators, and hybrid electric vehicles.
Wind energy conversion systems have become a key technology to harvest wind energy worldwide. In permanent magnet synchronous generator-based wind turbine systems, the rotor position is needed for variable speed control and it uses an encoder or a speed sensor. However, these sensors lead to some obstacles, such as additional weight and cost, increased noise, complexity and reliability issues. For these reasons, the development of new sensorless control methods has become critically important for wind turbine generators. This paper aims to develop a new sensorless and adaptive control method for a surface-mounted permanent magnet synchronous generator. The proposed method includes a new model reference adaptive system, which is used to estimate the rotor position and speed as an observer. Adaptive control is implemented in the pulse-width modulated current source converter. In the conventional model reference adaptive system, the proportional-integral controller is used in the adaptation mechanism. Moreover, the proportional-integral controller is generally tuned by the trial and error method, which is tedious and inaccurate. In contrast, the proposed method is based on model predictive control which eliminates the use of speed and position sensors and also improves the performance of model reference adaptive control systems. In this paper, the proposed predictive controller is modelled in MATLAB/SIMULINK and validated experimentally on a 6-kW wind turbine generator. Test results prove the effectiveness of the control strategy in terms of energy efficiency and dynamical adaptation to the wind turbine operational conditions. The experimental results also show that the control method has good dynamic response to parameter variations and external disturbances. Therefore, the developed technique will help increase the uptake of permanent magnet synchronous generators and model predictive control methods in the wind power industry.
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