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SVPWM Overmodulation Region II Control Method Based on the Chaos Ant Colony Algorithm
Zhang Siyan,Wang Xudong,Gao Junshan,Wu Xiaogang,Liu Jinfeng 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.4
The control method of space vector pulse width modulation (SVPWM) overmodulation region II has the disadvantages of a complicated process and large harmonic content. To solve these problems, this paper proposes an SVPWM overmodulation region II control method based on the chaos ant colony algorithm. Since the multiple control of the rotation angle ( θ ) in the SVPWM algorithm will bring about diff erent implementation eff ects, this paper uses the chaotic ant colony algorithm to optimize the control process of θ in overmodulation region II and summarizes the θ equations in each sector to achieve the goal of suppressing the total harmonic distortion ( THD ) in the output voltage vector. Simulation and experimental results demonstrate that this method makes the amplitude of the output voltage vector relatively continuous, thereby avoiding the harmonic content caused by the voltage jump of the traditional algorithm in overmodulation region II.
Adaptive Fault-tolerant Control for Trajectory Tracking and Rectification of Directional Drilling
Chi Zhang,Wei Zou,Ningbo Cheng,Junshan Gao 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.1
Motivated by the increasing demands on complex borehole trajectories in oil and gas directional drilling, an adaptive fault-tolerant control (AFTC) method for drilling trajectory tracking and rectification of rotary steerable system (RSS) is proposed by adopting actor-critic reinforcement learning (RL) and integral sliding mode control (ISMC) in the presence of system uncertainties and fault signals. Considering a discrete delay differential equation (DDE) with distance delays, uncertainties and fault signals, first we design an online learning framework via actor-critic RL and radial basis function neural network (RBFNN) in order to make drill bit can track pre-designed trajectory accurately and smoothly. Then in order to handle the fault signals problem, we utilize ISMC to eliminate it as weak as possible and rectify drilling trajectory which may derivate original direction caused by it. The system stability and convergence have been analyzed to ensure uniformly ultimately boundedness of tracking errors and fault-tolerant control signals. The proposed method would have wide application potentials in realizing the trajectory tracking and rectification with automatic operations of directional drilling. The effectiveness and accuracy of it are validated by simulation results with ramp and sine input signals.