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The advantages of fast charging speed and high efficiency of DC charging piles make the connection and cutting of electric vehicle (EV) loads relatively frequent. However, as a DC system, DC charging pile has the characteristics of low inertia and weak damping. In order to reduce the impact of EV load connection and cutting on the DC side voltage disturbance, a DC charging pile control method based on improved virtual inertia (VI) control is proposed. This paper firstly introduces VI control by analogy with virtual synchronous machines (VSM) technology. Secondly, the VI control is improved by using command filter backstepping integral sliding mode (CFBISM) control, in which the integral sliding mode (ISM) control is used to optimize the VI control to enhance the robustness of the system, and the command filter backstepping control is used to reconfigure the key parameters to avoid the computational inflation of the controller, while the ISM control is used to improve the current inner loop to further enhance the control effect. The stability of the proposed control strategy is then demonstrated by the Lyapunov stability criterion. Finally, through comparative simulation, it is verified that the DC-side voltage fluctuation can be limited within 2 V, the dynamic response speed is improved by about 0.1 s, and the perturbation of the key parameters in the steady state is limited to about 1 V, thus the superiority of the fast response speed and good robustness of the control proposed in this paper are verified by simulation.

Aiming at the voltage fluctuation problem caused by indirectness and uncertainty in new energy power generation system, the backstepping control strategy is firstly applied in electric spring (ES) system, and an ES backstepping control strategy with command filtering is proposed. According to the mathematical model of ES, the controller is designed by backstepping method and command filter is added to solve the computational inflation problem in ES backstepping control. Meanwhile, the error compensation signal is designed, and the stability of the system is verified by the Lyapunov stability theory. The effect of ES on critical load (CL) voltage stabilization is simulated when the grid-side voltage of the new energy power generation system fluctuates, and the sensitivity analysis of different system parameters to the control strategy is discussed in this paper. Compared with traditional proportional integral (PI) control, the dynamic response speed of CL voltage is improved by 0.07 s, while the CL voltage distortion rate is reduced by 31%. In parameter sensitivity analysis, the maximum deviation rate of CL voltage is 0.318%. Meanwhile, the maximum voltage amplitude fluctuation range that it can withstand is increased by 52.9 V. It is verified that the control strategy proposed in this paper has the advantages of fast response, low harmonic content and strong anti-interference ability.

In response to the poor disturbance rejection performance and issues of parameter perturbation and control precision in traditional control strategies for interior permanent magnet synchronous motors (IPMSM), a fuzzy sliding mode control strategy based on the super-twisting disturbance observer was proposed. This strategy enables wide-speed-range operation of IPMSM, and further improves rotational speed tracking precision and the system's disturbance rejection capabilities. Firstly,the speed control range was broadened by combining maximum torque per ampere ratio with the gradient descent method for weak magnetic control. Secondly, the super-twisting algorithm (STA) was utilized to design a disturbance observer, thus enhancing the system's ability to resist disturbances. In addition, to address the derivative explosion problem in Backstepping control, a second-order sliding mode differentiator was used to approximate the virtual control rate. The fuzzy logic system was adopted to approximate the nonlinear part in the model of IPMSM, reducing the impact of motor parameter perturbation on control performance. Finally, the stability of the proposed control strategy was confirmed by applying Lyapunov theory. Through simulation on the Matlab/Simulink platform, it was verified that under the control strategy proposed,IPMSM demonstrate superior wide-speed-range dynamic performance and robustness. [ABSTRACT FROM AUTHOR]

Summary: In this article, the state of charge (SoC) balancing problem of large‐scale electric vehicles (EVs) connected to the utility grid is addressed by designing a novel no circulating current cooperative adaptive SoC balancing control. First, considering different capacities and initial SoCs, an adaptive power distribution algorithm based on distributed dynamic consistency algorithm is blue developed to achieve the SoC balancing of large‐scale EVs connected to the utility grid. Then, considering the shortage of battery life caused by the circulating current during the long‐term charging and discharging process, an adaptive balance rate factor is designed to effectively avoid the generation of the circulating current. Then, an adaptive cooperative fuzzy terminal sliding mode controller is proposed for grid‐connected EVs to improve power tracking accuracy and enhance robustness. Considering the parameters' uncertainties and unmodeled parts of grid‐connected EVs, parameter adaptive estimation and fuzzy algorithm are used to approximate the unmodeled part. In addition, the boundedness of the adaptive estimation is guaranteed by using the projection operator. Finally, the validity and reliability of the designed control strategy are verified by simulations. [ABSTRACT FROM AUTHOR]