High-order moment stabilization for Markov jump systems with attenuation rate

The doubly fed differential linear active disturbance rejection control (DLADRC) in the speed loop control of permanent magnet synchronous motor (PMSM) produces observation time lag due to the bandwidth impact, which leads to the problem of slower dynamic response and poorer disturbance rejection performance of the system. To solve this problem, a speed controller of PMSM based on series lead correction DLADRC (SLC‐DLADRC) is investigated in this paper. Firstly, the speed loop of PMSM is modeled and the traditional LADRC is reconstructed to obtain DLADRC to improve the control performance of the system. Based on DLADRC, a phase lead correction unit is introduced, and a feedback differential extended state observer based on series lead correction (SLC‐DLESO) is investigated for observing the total disturbance of the system to further improve the system's anti‐disturbance performance. Then, the estimation error analysis of the studied SLC‐DLESO is performed and its stability performance is proved. The stability analysis of the SLC‐DLADRC control strategy is conducted using the Nyquist stability criterion. Finally, MATLAB/Simulink simulation and DSPACE semi‐physical platform are used to verify the effectiveness of the control strategy. Theoretical analyses and experimental results show that, without changing the bandwidth, SLC‐DLADRC not only improves the observation time lag problem but also extends the estimation range of the total disturbance. In the speed loop control of PMSM, the control strategy provides better dynamic response performance and anti‐disturbance under various operating conditions compared to the conventional LADRC and DLADRC.

Dynamic transport characteristics and performance response of commercial-size polymer electrolyte membrane fuel cell stack: An experimental study

Dynamic response characteristics of solenoid valves directly determined their performances. Among numerous parameters, the influence of magnetic isolation ring (MIR) on solenoid valve performance is crucial. Previous optimization studies have not conducted a systematic exploration and analysis of MIR. In this paper, a model of an AC solenoid valve considering the position of the MIR is proposed, and the model’s accuracy was verified by simulation and experiments. The electromagnetic force, response time, and magnetic field distribution at different positions of the MIR were analyzed, and the effect of the position of MIR on dynamic response characteristics of the solenoid valve was clarified. The results show that the MIR affects the dynamic response characteristics of the solenoid valve by changing the magnetic circuit. With the positive translation of the position of the MIR along the Z-axis, the electromagnetic force first increases and then decreases, and the response time first decreases and then increases. The position range of MIR with excellent dynamic response performance was obtained from the comprehensive consideration of response time and electromagnetic force. Finally, the optimization design for the dynamic response performance of the solenoid valves is realized.

To improve the dynamic response and disturbance rejection performance of a permanent magnet synchronous motor (PMSM) speed control system, this paper designs a speed control strategy of PMSM based on super-twisting sliding mode corrected differential linear active disturbance rejection (STSM-CDLADRC). First, the speed loop model of a permanent magnet synchronous motor based on traditional LADRC is established. Second, the observer of LADRC is reconstructed according to the principle of error control, and the differential linear extended state observer (DLESO) is obtained. Then, to solve the observation hysteresis problem existing in the DLESO, the phase lead correction unit is introduced, and a corrected DLESO is designed (CDLESO); on this basis, the feedback rate in LADRC is also improved by using the super-twisting sliding mode control algorithm to design the super-twisting sliding mode linear state error feedback rate (STSM-LSEF), which improves the dynamic response performance of the system. Finally, the effectiveness and feasibility of the designed control strategy are verified by MATLAB/Simulink simulation and an experimental platform, and the results show that in the speed control system of the PMSM, the strategy effectively improves the dynamic response performance and anti-disturbance performance of the system.

Buck-buck/Boost power factor correction (PFC) converter is a great choice to compensate the inherent dead zones in the input current of buck PFC converter. However, whether the converter operates with traditional constant on-time control in critical conduction mode (CRM) or with conventional constant duty-cycle control in discontinuous conduction mode (DCM), the power factor (PF) is low, especially at low input voltage. Therefore, fixed on-time ratio control (FOTRC) and fixed duty-cycle ratio control (FDCRC) are proposed for CRM/DCM buck-buck/boost PFC converter to achieve high PF, respectively. Both control methods maximize PF over wide input voltage range by adjusting on-time or duty-cycle of buck/boost mode and buck mode. Compared with the traditional controls, the proposed control methods also have advantage of increasing efficiency. Furthermore, for improving dynamic response performance, smooth and rapid dynamic response control (SRDRC) is put forward, which can reduce the regulation time and output voltage overshoot/undershoot when the load or input voltage changes abruptly. In addition, the implementation circuits combining FOTRC/FDCRC and SRDRC are designed. Two prototypes have been built and tested in the lab to demonstrate the validity of the theoretical analysis.

This paper analyzes the working principle of the single-phase inverter, studies the problems of slow dynamic response and weak anti-interference ability of the existing PI controller scheme inverter, and designs a linear active disturbance rejection controller. Under this control method, the dynamic response performance and anti-interference ability of the inverter have been significantly improved compared with the PI controller. In this paper, the bandwidth method is used to simplify the design of ADRC and the parameters are set. The control effect is verified by bus jump and load jump. The simulation is carried out in Simulink, and the experimental platform is built to verify the scheme. The simulation and experimental results verify the effectiveness of the LADRC controller, as well as stronger dynamic response performance and anti-interference ability compared with the PI controller.

In order to improve the convergence rate and disturbance reject ability of magnetic levitation system, this paper proposes an observer-based adaptive non-singular terminal sliding mode controller. Firstly, the dynamical model of magnetic levitation ball system is deduced, Then on the basis of the sliding mode control (SMC), an adaptive non-singular terminal sliding mode control(ANTSMC) is constructed. The ANTSMC can speed up the convergence speed and reduce chattering. In order to enhance the anti-interference ability, state estimation are cooperated into ANTSMC by using state observer. The simulation results confirmed the closed-loop magnetic levitation system performance both in dynamic response and disturbance attenuation, corresponding quantitative comparison could also show the advantages of proposed control scheme.

In this article, a deadbeat predictive current control (DPCC) method based on gain factor self-tuning technology is proposed, which can effectively improve the dynamic response performance and robustness of the control system. Since the performance of DPCC is highly dependent on parameter accuracy, this article establishes a closed-loop transfer function model of the DPCC method and analyzes in detail the impact of parameter mismatch on the current dynamic response performance. Then, the current error caused by parameter mismatch is suppressed by designing the gain factor, on this basis, a parameter self-tuning algorithm based on gradient descent optimization method is constructed. Compared with traditional parameter identification algorithms, the proposed method has the advantages of strong versatility and greatly reduces computational burden. Finally, the accuracy of the tuning results of the proposed method is proved by experimental results, which effectively suppresses the influence of parameter mismatch and improves the current response performance.

To improve the dynamic and steady-state control performance of permanent magnet synchronous motors under the three-vector model predictive current control method, this study proposes a switching current predictive control method based on the exponential moving average algorithm, which evaluates the magnitude of the change of the q-axis current slope in real time to discriminate the motor’s operating conditions and selects the optimal control method for different operating conditions. Meanwhile, the traditional three-vector model predictive current control method is improved by introducing a comparison mechanism for the q-axis current slope to select the second effective voltage vector, avoiding the secondary optimization calculation of the value function and reducing the computational complexity of the traditional method. By comparing the proposed method with the traditional three-vector model predictive current control method, the experimental results prove that the proposed method improves the system’s dynamic response and steady-state performance.

To overcome the shortcomings of the conventional continuous control set model predictive current control (CCS-MPCC), such as large overshoot and poor robustness, an extended surface-mounted permanent magnet synchronous motor (SPMSM) model-based multistep error tracking CCS-MPCC (MSET-CCSMPCC) is proposed in this article. First, a traditional CCS-MPCC is derived based on the conventional SPMSM model and its robustness is analyzed by considering the parameter mismatches. Second, an extended SPMSM model is given by incorporating the lumped disturbances into one disturbance part. Third, a sliding mode differentiator improved fast terminal sliding mode disturbance observer is designed to track the disturbances. Fourth, by compensating the extended SPMSM model for the estimated d- and q-axes disturbances, an extended SPMSM model-based CCS-MPCC (EXM-CCSMPCC) is designed. However, the EXM-CCSMPCC has serious step response overshoot. Fifth, an extended SPMSM model-based single step error tracking CCS-MPCC is presented, whose dynamic response and steady-state performances deteriorate when the overshoot is reduced. Finally, an MSET-CCSMPCC is proposed to reduce the overshoot and improve the robustness while maintaining excellent dynamic and steady-state performances. Experiments are implemented on a field-programmable gate array based hardware system to verify the excellent performances of the proposed method.

In order to improve the dynamic response and disturbance rejection performance of electric machines, a deadbeat predictive speed control (DPSC) scheme for a permanent magnet synchronous motor (PMSM) is proposed. To begin with, a DPSC controller was proposed with the purpose of achieving precise control for the next control cycle, and the control parameters were determined based on the optimal parameter design method. For better application, performance comparisons were made with a conventional PI control, and the mismatch effects of inertia and torque were analyzed. In order to improve the disturbance rejection performance of the system, an extended sliding mode observer (ESMO) was constructed to compensate for disturbances. Experimental verification with a conventional PI control indicates that the proposed DPSC control can reduce the speed response time from 0.675 s to 0.650 s. When the electric machine operates stably and is applied to a torque disturbance of 0.4 Nm, the speed fluctuation and settling time can be reduced from 9 rpm and 1.7 s to 6 rpm and 0.5 s, respectively. This proposed method effectively enhances the speed control performance of PMSM and can be applied to high-performance electric machine applications.

Control comparison of conventional and thermally coupled ternary extractive distillation processes with recycle splitting using a mixed entrainer as separating agent

Super-twisting sliding mode control (STM) offers advantages such as fast response and low demand on motor model accuracy, and is attractive for the permanent magnet synchronous motor (PMSM) servo systems. However, the inherent chattering issue and limited disturbance rejection capability degrade its servo control performance. To overcome these limitations, this paper proposes an improved STM approach using a variable reaching law super-twisting sliding mode (VRSTM) strategy, integrating a high-order disturbance observer (HODOB) to estimate all perturbations including motor parameter mismatch, to achieve a high-precision speed control for the servo systems. Compared to the conventional reaching law, the proposed VRSTM accelerates convergence during trajectory deviations from the sliding surface while decelerating near the surface, hence achieving a better dynamic response performance and chattering mitigation. Furthermore, by implementing the HODOB, the perturbations including motor parametric variations are estimated to enhance the disturbance rejection capability of the proposed VRSTM approach. Theoretical analysis confirms the validity of the proposed method in improving the dynamic performance, suppressing chattering phenomena, and enhancing disturbance rejection capabilities for PMSM servo drives. Simulation and experimental results confirm the effectiveness and robustness of the proposed method.

This paper presents the finite-time control problem for permanent magnet synchronous motor (PMSM) speed servo system using different kinds of finite-time control methods. Integral terminal sliding mode controller and continuous finite-time controller are designed respectively for the speed loop and d-axis current loop. The proof of finite-time stability for PMSM speed servo system is also given. Compared with the corresponding control method of asymptotical stability, the controller based on the finite-time control can make the output of system track the desired speed reference signal in finite time and obtain a better dynamic response and anti-disturbance performance. Meanwhile, considering the large chattering phenomenon caused by high switching gains, a composite integral terminal sliding mode control method based on disturbance observer is proposed to reduce chattering. Through feed-forward compensation based on disturbance estimation, the composite integral terminal sliding mode controller may take a smaller value for the switching gain without sacrificing disturbance rejection performance. TMS320F2808 DSP experimental results are provided to show the superiority of the proposed methods.

Hybrid wind-wave systems combine a floating offshore wind turbine (FOWT) with wave energy converter (WEC) units, boosting overall power production and reducing operating expenses, thereby decreasing the Levelised Cost of Energy. Amongst the various WEC concepts to advance to the stage of full-scale prototype development, the Oscillating Water Column (OWC) stands out as one of the most promising. The primary objective of this study is to support the development of a floating, hybrid OWC – wind energy module, intended for deployment in the Fiji Islands. The research integrates the University of Maine’s VolturnUS-S Semi-Submersible FOWT with three cylindrical OWCs embedded within its platform. Experimental investigations evaluated the power performance of the OWCs and the dynamic response of the combined system under various regular wave conditions. Different OWC orifice plate configurations were also tested to assess the impact of power take-off (PTO) damping on platform stability and power generation efficiency.Results indicate that incorporating OWC WEC units significantly improves platform stability compared to the stand-alone VolturnUS-S platform. Additionally, a spatial variation in power generation was observed across the three OWCs, with the aft chamber producing more power than the port and starboard chambers. These findings highlight the substantial development potential of the combined OWC – wind concept, due to its increased power output and improved platform stability. The outcomes of this study are expected to inform the design, construction, and operation of practical hybrid wind – wave energy systems.