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The precise control of centrifugal hydrogen compressor (CHC) driven by high-speed permanent magnet synchronous motor (PMSM) is the key to the stable and efficient operation of hydrogen fuel cell (HFC). In this paper, an adaptive current deviation decoupling control (CDDC) strategy based on variable step size affine projection algorithm (VSS-APAs) is proposed to solve the high-speed PMSM control problem caused by current cross-coupling and parameter perturbation under complex operating conditions. Firstly, the step size is dynamically adjusted by VSS-APA through a normalized gradient descent to respond to system fluctuations, achieving rapid parameter identification during dynamic changes and accurate tracking in steady states. Secondly, stator inductance, magnetic flux linkage, stator resistance, and disturbance torque are identified in two-time-scale based on the characteristics of parameter changes, overcoming the rank deficiency in motor mathematical equations. Finally, utilizing online-identified motor parameters, the gains of the CDDC are adjusted, and compensation is applied for back electromotive force (BEMF) and disturbance torque, thereby ensuring the control accuracy of the motor under parameter perturbations and system disturbances. Experimental results demonstrate that the proposed method enhances the responsiveness and accuracy of the control strategy through efficient parameters identification. Consequently, it guarantees high-efficiency and stable performance of the CHC across different working conditions, markedly advancing the overall functionality and dependability of hydrogen energy system. • An adaptive current decoupling control scheme for high-speed permanent magnet synchronous motor is proposed. • A two-time-scale VSS-APAs for online identification of motor parameters is designed. • The effectiveness of this method is verified by experiments. [ABSTRACT FROM AUTHOR]

The three-level neutral-point-clamped (NPC) active power filter (APF) is suitable for harmonic compensation in high voltage and large capacity applications. And, the harmonic compensation effect of APF depends on its dynamic performance and control. This paper propose a repeat proportional integral (PI) decoupling control strategy with linear active disturbance rejection (LADRC) to address the issues of detection in complex harmonic current and power supply current distortion when the nonlinear load varies. To simplify the design of LADRC, this paper adopts inverter current feedback control. Firstly, repeat control is introduced to optimize the traditional PI controller, which improves the compensation accuracy while ensuring the dynamic response capability of the control system. Then, to address the serious coupling of the system model in the d-q coordinate system, a reduced order linear active disturbance rejection (LADRC) control is introduced. The PI and linear extended state observer (LESO) control method is adopted in the outer voltage loop to maintain stable DC voltage and improve the ability to suppress voltage overshoot during grid connection. The effectiveness of this control method has been verified through MATLAB/Simlink. The results show that, compared with the repeat PI method, the control method based on repeat PI–LADRC can achieve better decoupling control, improve robustness and anti-interference ability, enhance the performance of the original system, and can significantly improve the harmonic suppression capability of the APF. [ABSTRACT FROM AUTHOR]

With the ongoing development of electronic power technologies, harmonic pollution in the power grid has become a topic of great concern. This study takes a substation as its background. The safe and steady operation of the station's equipment was impacted by a 10 kV bus's harmonic current, which was significantly higher than the required amount. We propose a sliding-mode current decoupling control strategy based on an internal model to address the problems of complex harmonic current detection and distortion in the power supply current when there are nonlinear load changes in hybrid active power filters. By establishing a mathematical model for a HAPF, our proposed strategy can be used for inner current loops with the goal of stability, decoupling control between the d- and q-axes, fast-tracking harmonic reference currents, and optimizing the controller by enhancing the system's anti-jamming performance to ensure that the system operates stably when line parameter ingressions or step changes in the load demand occur. The outer voltage loop uses the fractional-order sliding-mode control method to keep the capacitor voltage smooth and to dynamically adjust when the load changes suddenly. Finally, this filter is compared with a filter controlled by a PI in MATLAB/Simulink, and the feasibility and effectiveness of the proposed control strategy are verified based on a diode-embedded three-level parallel-type HAPF platform. The simulation and experimental results show that our sliding-mode current decoupling control strategy based on the internal mode is characterized by simplicity, stability, and fast responses. [ABSTRACT FROM AUTHOR]

The LCL-type grid-connected inverter (GCI) is a critical device for realizing energy transmission between distributed generation and the power grid. The current control of the GCI typically requires multiple sensors to enable active damping and grid-side current control, which increases the system cost. A full-state observation system based on state reconfiguration with quasi resonant-extended state observer was proposed, in which just a signal inverter-side inductor current sensor was required to realize real-time observation of the desired state variables. Meanwhile, the constraint of high observer bandwidth required for conventional extended state observer to track sinusoidal signals was solved by adding a quasi resonant link to the observation channel of each state variable of extended state observer. Moreover, the active disturbance rejection control current controller was designed in the dq frame, which simplified the complicated decoupling process of conventional methods by treating the coupling as part of the total disturbance. The software numerical simulation illustrates that the control strategy show excellent observation results and current tracking performance.

Copyright of Power Generation Technology is the property of Power Generation Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Six‐phase permanent magnet linear synchronous motor (PMLSM) for electromagnetic launch (EML) system presents the characteristics of a high order, nonlinearity, multivariable, strong coupling, and nonperiodic transient operation in the synchronous rotating coordinate system, posing a great challenge to the dynamic response ability of the current loop. Existing research on current decoupling control (CDC) mainly focuses on cross decoupling within a three‐phase system, even though there are neither decoupling methods for multiphase systems nor effective evaluation criteria for the decoupling and dynamic response performances. From this perspective, this paper first presents an equivalent reduced‐order complex‐matrix dynamic mathematical model of six‐phase PMLSM and analyze its transient coupling characteristics during the process of EML. Then, the CDC methods of six‐phase PMLSM based on direct compensation and matrix diagonalization principles are realized, respectively, to accomplish the cross decoupling and back electromotive force decoupling within and between different three‐phase windings. Finally, an all‐round method is proposed, for the first time, to evaluate the decoupling performances and dynamic response performances of different CDC strategies for six‐phase PMLSM. Significant superiority of deviation decoupling regulator in decoupling performance and robustness are verified based on high‐speed EML experimental platform of six‐phase PMLSM.

Copyright of Control Theory & Applications / Kongzhi Lilun Yu Yinyong is the property of Editorial Department of Control Theory & Applications and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

For better performance, different current control schemes are used in LCL-type grid-connected converters. However, these schemes are mostly used in three-phase grid-connected converters and multiple current sensors are needed. To address these issues, a current decoupling control scheme for single-phase grid-connected converters in rotating reference frame is proposed in the paper. Because an extended state observer is adopted in the control scheme, only one current sensor is needed and the complicated coupling relationships between the d axis components and q axis components can be eliminated completely. Moreover, to improve the dynamic and steady-state performance of converters, a state feedback closed-loop system structure and nonlinear controllers are adopted. The current decoupling control scheme is validated in an LCL-type single-phase grid-connected converter. The experimental results show that a fast-dynamic response under load change and voltage sag can be achieved besides preferable static performances with the proposed control scheme.

In the permanent magnet direct-drive wind power grid-connected system, in order to solve the coupling problem between d -axis and q -axis currents and to improve the disturbance rejection performance of direct current (DC) bus voltage under grid faults, a new dual closed-loop structure based on linear active disturbance rejection control (LADRC) is proposed. This new dual closed-loop control includes current inner loop decoupling control and DC bus voltage outer loop control with first-order LADRC. As the LADRC has the advantages of decoupling and disturbances rejection, it is applied to the control of wind power grid-connected inverter. Through analysis, it is demonstrated that the current decoupling control is simpler than proportional integral (PI) control algorithm, the dynamic response speed is faster, and the DC bus voltage control has better anti-disturbance. Finally, a 1.5 MW direct-drive permanent magnet wind power system was established through digital simulation, and the control effects of the two control modes under different working conditions are compared. The simulation results verify that the proposed dual closed-loop control based on first-order LADRC is superior to PI double closed-loop control in terms of decoupling performance and disturbance rejection performance under grid faults.

With the rapid development of renewable energy generation, single-phase grid-connected inverters have been widely applied in modern power systems. Since the power output of the renewable sources is continuously changing, independent active/reactive power control and a rapid current tracking performance is supposed to be achieved in a single-phase grid-connected inverter. However, the poor orthogonal-axis-constructing strategy and the ineffective decoupling in some widely-used controllers have severely weakened the dynamic performance of the single-phase inverter. To deal with the challenges above, this study proposes a comprehensive control strategy for current control in a single-phase grid-connected inverter. In the proposed control strategy, a virtual closed-loop is constructed to improve the dynamic performance and realize independent power control under a synchronous frame. Then, complex vector theory is used to model the virtual closed-loop based single-phase inverter, and a novel digital controller is designed based on zero-pole cancellation and minimum beat control to completely decouple the active/reactive components and achieve a supreme current tracking performance. Experimental results are shown to validate the feasibility of the proposed current controller. [ABSTRACT FROM AUTHOR]

In the permanent magnet direct-drive wind power grid-connected system, in order to solve the coupling problem between d -axis and q -axis currents and to improve the disturbance rejection performance of direct current (DC) bus voltage under grid faults, a new dual closed-loop structure based on linear active disturbance rejection control (LADRC) is proposed. This new dual closed-loop control includes current inner loop decoupling control and DC bus voltage outer loop control with first-order LADRC. As the LADRC has the advantages of decoupling and disturbances rejection, it is applied to the control of wind power grid-connected inverter. Through analysis, it is demonstrated that the current decoupling control is simpler than proportional integral (PI) control algorithm, the dynamic response speed is faster, and the DC bus voltage control has better anti-disturbance. Finally, a 1.5 MW direct-drive permanent magnet wind power system was established through digital simulation, and the control effects of the two control modes under different working conditions are compared. The simulation results verify that the proposed dual closed-loop control based on first-order LADRC is superior to PI double closed-loop control in terms of decoupling performance and disturbance rejection performance under grid faults. [ABSTRACT FROM AUTHOR]