Synchronous Speed Research Articles

Multi-Motor Cooperative Control Strategy for Speed Synchronous Control of Construction Platform

Barrel-type structures are ubiquitous in industry and life. A novel construction platform of barrel-type structures is introduced, and it involves a multi-motor system. The synchronous control of multiple motors has great importance. To guarantee the high precision, high stability, and fast response for the collaborative control of multiple motors, this paper proposes a multi-motor cooperative control strategy. Firstly, a speed synchronization control structure between multiple permanent magnet synchronous motors (PMSM) is designed by way of the mean coupling control structure. Then, the conventional PID controller is improved by machine learning. Moreover, a radial basis function neural (RBF) network is introduced to the conventional PID algorithm for system identification processing, and the gradient descent algorithm is used for parameter updating. An improved variable speed integral term is introduced into the integral term of the conventional PID algorithm to eliminate the error as soon as possible. Finally, it is verified via numerical simulation experiments that show the multi-motor cooperative control strategy has high anti-interference ability and robustness.

A fast data-driven topology identification method for dynamic state estimation applications

This paper proposes a fast topology identification method to avoid estimation errors caused by network topology changes. The algorithm applies a deep neural network to determine the switching state of the branches that are relevant for the execution of a dynamic state estimator. The proposed technique only requires data from the phasor measurement units (PMUs) that are used by the dynamic state estimator. The proposed methodology is demonstrated working in conjunction with a frequency divider-based synchronous machine rotor speed estimator. A centralized and a decentralized approach are proposed using a modified version of the New England test system and the Institute of Electrical and Electronics Engineers (IEEE) 118-bus test system, respectively. The numerical results in both test systems show that the method demonstrate the reliability and the low computational burden of the proposed algorithm. The method achieves a satisfactory speed, the decentralized approach simplifies the training process and the algorithm proves to be robust in the face of wrong input data.

Output-Feedback Multi-Loop Positioning Technique via Dual Motor Synchronization Approach for Elevator System Applications

This paper devises an output-feedback multi-loop positioning technique adopting the speed observer and multi-motor synchronizer, targeting the dual (master and slave) motor elevator system applications, providing the three contributions. First, the order-reduction observer continuously extracts the speed information from the motor position measurement, independent of the system model information. Second, the order-reduction stabilizer accomplishes the speed synchronization tasks for both the master and slave motors. Third, the resultant feedback system guarantees to exponentially recover the desired first-order transfer function from the reference to the actual motor position despite the model-plant mismatches. The prototype elevator system adopting the dual motor experimentally validates the practical advantages of the proposed technique.

Sensorless Control of Variable-Speed SCIG Wind Energy Conversion Systems Based on Rotor Flux Estimation Using ROGI-FLL

In this article, a novel sensorless control method for variable-speed squirrel-cage induction generator (SCIG) wind power systems with simple rotor flux estimation is proposed. The rotor flux linkages are estimated using a reduced-order generalized integrator (ROGI)-frequency-locked loop (FLL), which regards the rotor back electromotive forces (EMFs) found from the generator model as its inputs. Based on these rotor flux linkages, the rotor flux angle can be estimated through direct trigonometric relations. Then, to avoid the speed estimation error caused by the FLL under stator frequency variations, the synchronous speed is estimated from the aforementioned rotor flux angle via the derivative. Owing to the excellent harmonic rejection capability of the ROGI, the proposed rotor flux estimation is robust against measured high-frequency ripple components. The analysis of ROGI response in the presence of dc offset in the rotor back EMFs is provided as well, and it shows that the proposed method is not faced with the saturation under those conditions. Performance comparisons between the proposed method and the existing dual second-order generalized integrator (SOGI)-FLL-based method have been conducted via both simulations and experiments, thereby verifying the feasibility of the proposed method.

MPC-Based Coordinated Control of Gear Shifting Process for a Power-split Hybrid Electric Bus with a Clutchless AMT

Two-speed clutchless automated manual transmission (AMT) has been widely implemented in electric vehicles for its simple structure and low cost. In contrast, due to the complex response characteristics of powertrain, utilizing clutchless AMT in a hybrid power system comes with complex coordination control problems. In order to address these issues, a power-split hybrid electric bus with two-speed clutchless AMT is studied in this paper, and a coordinated control method based on model predictive control (MPC) is used in gear shifting control strategy (GSCS) to improve gear shifting quality and reduce system jerk. First, the dynamic model of power sources and other main powertrain components including a single planetary gear set and AMT are established on the basis of data-driven and mechanism modeling methods. Second, the GSCS is put forward using the segmented control idea, and the shifting process is divided into five phases, including (I) unloading of drive motor, (II) shifting to neutral gear, (III) active speed synchronization by drive motor, (IV) engaging to new gear, and (V) resuming the drive motor’s power, among which the phases I and V have evident impact on the system jerk. Then, the MPC-based control method is adopted for these phases, and the fast compensation of driving torque is realized by combining the prediction model and quadratic programming method. The simulation results show that the proposed GSCS can effectively reduce shift jerk and improve driving comfort. This research proposes a coordinated control strategy of two-speed clutchless AMT, which can effectively improve the smoothness of gear shifting and provides a reference for the application of two speed clutchless AMT in power-split hybrid powertrains.

Intermittent pinning synchronization between two hyperbolic coupled networks with time-varying delays

This paper is devoted to synchronization between two hyperbolic coupled networks (HCNs) with time-varying delays via aperiodically intermittent pinning control (AIPC). Based on the Lyapunov function with a piecewise continuous function, sufficient criteria of HCNs with internal delays only and with hybrid delays are obtained, separately. And it is found that the convergence speed of synchronization of HCNs with hybrid delays is slower than that with internal delays only. Furthermore, two simulation results are presented to verify the theoretical results.

Concept and Implementation of Embedded Magnetic Encoder in Flux-Switching Permanent-Magnet Machines

Rotor angle is essential in permanent-magnet (PM) brushless machines. Recently, an embedded magnetic encoder (EME) scheme, consisted of linear Hall sensors installing inside of the PM machines, has been proposed to sense the flux density and consequently provides rotor position. Compared with traditional optical encoder and resolver, the linear Hall sensor prevails over in both space and cost. The aforementioned scheme is employed successfully in rotor-PM machines, where a PM-excited field rotates at the synchronous speed. In this article, the feasibility of EME in stator-PM flux-switching machine is validated, where PMs are located in stator, resulting in a stationary PM field. The stator slots are selected as installation position of linear Hall sensors to avoid changing the existing structure of machines. The variation of linear Hall signal is due to the changing reluctance of rotor rather than rotating PMs. Then, a decoding algorithm is designed based on an add-up operation, a complex coefficient filter, and a synchronous reference frame phase-locked loop. Finally, experiments on a prototype machine are conducted to validate the effectiveness of EME scheme under both speed-varying and load-varying conditions.

Design and Implementation Six-Steps Inverter Using Fuzzy Sugeno in Permanent Magnet Synchronous Machines

Controlling the speed of the permanent magnet synchronous machines plays an essential role in the industrial process and keeps the permanent magnet synchronous machines running quickly and efficiently. Even if the load changes, the rate speed of the permanent magnet synchronous machines should be adjusted to a constant speed. An excellent permanent magnet synchronous machines speed control system must respond quickly and accurately. However, in practice, rarely find a permanent magnet synchronous machines controlled to achieve a certain speed. This research presents an analysis of fuzzy logic control using seven membership functions for speed control of permanent magnet synchronous machines. Rotor speed control is performed on the rotor voltage by changing the duty cycle value. This voltage change affects the torque of the engine. Adjust the speed by changing the input voltage of the permanent magnet synchronous machines with the six-steps inverter. In the open-loop test (without control), the system cannot reach the desired setting and will only run after input from the throttle. In a closed loop (using fuzzy logic control), the system can achieve the desired setting in 90 seconds even if the setpoint is changed and can move to the setpoint.

Non-singular terminal extended sliding mode control of permanent magnet synchronous motor based on variable exponential reaching law

A non-singular terminal extended sliding mode control method based on variable exponential reaching law is presented because the permanent magnet synchronous motor speed control system is subject to parameter disturbance, external disturbance, and end effect. In order to accomplish global rapid convergence and get rid of singularity, a non-singular terminal extended sliding mode surface is first created. After the system reaches the sliding mode surface, a new extended state variable is constructed in accordance with the first-order angular velocity model, and a new better exponential reaching law is utilized to eliminate chattering. Finally, a disturbance observer is designed to detect the disturbance during motor operation in real-time and add it to the speed control loop as a compensation. The simulation findings demonstrate that, in comparison to the conventional sliding mode control strategy, the suggested variable-parameter non-singular terminal sliding mode control strategy lowers the effect of disturbance on the motor’s real operation and has the benefits of rapid convergence speed, good resilience, minimal speed overshoot, and high control precision.

Discrimination of Oceanic Whitecaps Derived by Sea Surface Wind Using Sentinel‐2 MSI Images

AbstractOceanic whitecaps, as a manifestation of the wind‐wave breaking process and the medium of air‐sea exchange, play an important role in sea surface research. The observational data of oceanic whitecap coverage are generally in situ photographs or videos. The use of spaceborne optical sensors to capture oceanic whitecaps could provide more spatial distribution and dynamic marine environment information. In this study, more than 100 Sentinel‐2 Multi‐Spectral Instrument (MSI) images and corresponding synchronous buoy wind speed data were collected to investigate oceanic whitecaps. A curvature image processing method was employed to successfully identify oceanic whitecaps in MSI images and the whitecap coverage was estimated based on the whitecap recognition results. We established a power‐law model of MSI‐estimated whitecap coverage (W) and whitecap number density with buoy‐measured wind speed at a height of 10 m above the sea surface (U10). In addition, the differences between the MSI‐derived model and in situ measurement‐derived models which are mainly caused by the scale effect of optical remote sensing, are discussed. The whitecap‐wind model demonstrates that MSI images can improve the quantification of sea surface wind speed with high spatial resolution. MSI images were used to estimate regional high‐spatial resolution (4 km) wind speeds, and the merged results (0.25°) were verified with the hourly wind products of the fifth generation European ECMWF (Centre for Medium‐Range Weather Forecasts) atmospheric reanalysis (ERA5). Moreover, the influence of sunglint on whitecap recognition and whitecap coverage was also analyzed. The reflectance of whitecap‐affected pixels in MSI images increased obviously with wind speed compared with background seawater in weak sunglint reflection area. These results indicated that the parameters of oceanic whitecaps derived from high‐spatial resolution optical images can be used to estimate wind speed and provide a new approach for monitoring marine dynamic environments in the future.

EEG-based analysis of various sensory stimulation effects to reduce visually induced motion sickness in virtual reality

The use of virtual reality (VR) is frequently accompanied by motion sickness, and approaches for preventing it are not yet well established. We explored the effects of synchronized presentations of sound and motion on visually induced motion sickness (VIMS) in order to reduce VIMS. A total of 25 participants bicycle riding for 5 min with or without sound and motion synchronization presented on a head-mounted display. As a result, the VIMS scores measured by the fast motion sickness scale and simulator sickness questionnaire were significantly lower in the participants who experienced the riding scene with sound and motion than those who experienced the riding scene with sound only, motion only, or neither. Furthermore, analysis of the EEG signal showed that the higher the VIMS, the significant increase in alpha and theta waves in the parietal and occipital lobes. Therefore, we demonstrate that the simultaneous presentation of sound and motion, closely associated with synchronous and visual flow speed, is effective in reducing VIMS while experiencing simulated bicycle riding in a VR environment.

50 마력 유도기의 전동기 운전 및 발전기 운전시의 특성 분석

The induction machine can be operated with a motor or a generator before and after the synchronous speed. The induction machine uses the same equivalent circuit diagram for both the motor and the generator. Therefore, the value obtained through the factory test can be applied as a parameter of the same equivalent circuit diagram. The output of the induction motor corresponds to 100% operation of the load connected to the shaft at the rated rotation speed, but the output of the induction generator corresponds to the active power obtained through the stator by mechanical input to the shaft. Therefore, even with the same equivalent circuit, the efficiency may be different because the electric power is different when operating with a motor or a generator. BRIn this study, we analyzed the efficiency with input power by voltage and current and mechanical output by angular speed and torque when driving a motor with a 50㏋ induction machine, and also the efficiency of stator electrical output for mechanical input during generator operation also analyzed.

Deployment and performance measurement of renewable energy based permanent magnet synchronous generator system

Permanent magnet synchronous generator (PMSG) is one of the promising solutions for large power generation systems due to its many advantages. The off-grid and micro/pico-hydro power stations are located near to the loads and equipped with constant speed/power turbine sources. In this paper, an attempt is made to design, develop, and deploy a three-phase PMSG generating system for the small scale off-grid dedicated load applications. In this experimental study, a constant speed source, which is an emulation of a micro/pico-hydro turbine is used as the prime mover to the generator. The prime mover is mechanically coupled to the rotor of the generator and which is controlled by an AC driver to make the PMSG run at synchronous speed for all the time of the experiment to generate the required voltage and frequency. The performance of the three-phase PMSG is measured and analyzed so that the proposed system obeys the good power quality for the pre-defined various maximum loading conditions.

A variable wind harvesting based induction generator using variable voltage and variable frequency converter for renewable energy applications

ABSTRACT This paper proposes the design and development of a power electronic converter intended for induction generator (IG) to harvest the power generated from variable wind in a wind energy conversion system (WECS). The squirrel cage induction generator (SCIG) is anticipated for fairly fixed speed operation, while its speed should be super-synchronous with respect to the synchronous speeds corresponding to the frequency of the receiving alternating current bus bar. In the existing WECS, SCIG requires a minimum wind velocity below which generation is not possible. The novelty of the proposed method is that the range of wind velocities can be selected over which generation is possible. To achieve this, the proposed system makes use of a variable voltage and variable frequency converter (VVVFC). Depending upon the wind velocity, the frequency of the VVVFC is adjusted such that the speed of the turbine and hence the IG are virtually maintained at super synchronous speeds with respect to the frequency of the AC side of the VVVFC. In addition, the perturb and observe-based maximum power point tracking (MPPT) scheme is also implemented. The proposed methodology also includes a series compensated buck–boost converter (SCBBC) inserted between the battery and the direct current link of the final inverter that feeds an RL load. Simulation in the MATLAB Simulink environment is carried out, and an experimental prototype has also been developed to validate the proposed method. Based on the results, it is found that the proposed variable speed system with the integration of VVVFC, SCBBC, and MPPT harvests is 78% greater than the conventional fixed speed system.

A multi-motor speed synchronization control enhanced by artificial bee colony algorithm

Relative coupling control (RCC) structure is widely used for multi-motor speed synchronization control. To improve the performance of multi-motor synchronous control, artificial bee colony (ABC) algorithm is developed and applied for enhancing RCC structure. The RCC structure optimized by the ABC algorithm is called the RCC-ABC structure. In the RCC-ABC structure, the ABC algorithm optimizes both the fixed compensation factor in the speed compensator and the parameters of the PID controller acting as a tracking controller. Simulation experiments based on a four-motor system are conducted to validate the efficiency of the RCC-ABC structure. Simulation results show that the RCC-ABC structure has better synchronization and tracking performance compared to the RCC structure.

Dynamic Event-Triggered Terminal Sliding Mode Control Under Binary Encoding: Analysis and Experimental Validation

This paper designs a novel nonsingular terminal sliding mode control (TSMC) scheme for a class of nonlinear systems under binary encoding transmission. To further ease the communication overheads between the plant and the controller, a dynamic event-triggered mechanism is also introduced to the TSMC design. Sufficient conditions are proposed, respectively, for guaranteeing the reachability to a practical sliding mode and the ultimate boundedness of the closed-loop system, in which the effects from the binary encoding and the dynamic event-triggered protocol are quantified clearly. The Zeno phenomena for the developed dynamic event-triggered mechanism is excluded via an explicit analysis. Finally, the feasibility and effectiveness of the proposed scheme are demonstrated by a numerical example and a real experiment on permanent magnet synchronous motor speed regulation system.

Observer‐based sliding mode control for permanent magnet synchronous motor speed regulation system with a novel reaching law

Observer‐based sliding mode control for permanent magnet synchronous motor speed regulation system with a novel reaching law

Novel Steel-Bar Starting Cage Line-Start Permanent Magnet Machine With Spoke-Type Insulation Layers

A line-start permanent magnet (LSPM) machine can be regarded as the integration of an induction motor and a permanent magnet synchronous motor (PMSM), so it has both self-starting capability as the induction motor and high efficiency as PMSM. As the cage winding on the rotor of LSPM only works at the starting process, it competes with permanent magnets for the space of a rotor. To solve this paradox, a steel-bar starting cage-based LSPM machine is proposed and analyzed in this article. Steel has larger resistivity than aluminum and copper, which can increase the starting torque and reduce the impact current of cage winding at the starting stage. Due to high permeability of steel, magnetic flux can also flow through steel-bar cage winding at synchronous speed. A steel-bar starting cage and a traditional aluminum starting cage winding are compared based on a four-pole LSPM machine using finite-element analysis (FEA) in this article. It is verified that although the self-starting capability of steel-bar cage winding is reduced due to the leakage flux, the performance at synchronous speed such as torque density and torque ripple is improved.

PMSM sliding mode control based on novel reaching law and extended state observer

To improve the dynamic quality and control performance of the permanent magnet synchronous motor speed control system, a novel sliding mode control method with improved reaching law for PMSM was proposed, which has a shorter reaching time and small system chattering. An extended state observer (ESO) based on the hyperbolic tangent function for the sliding mode controller is designed to realize the real-time tracking of the mechanical angular velocity and load disturbance of the motor, which can weaken the influence of the internal parameter perturbation and external load disturbance. The performance of the novel sliding mode controller for PMSM was simulated based on MATLAB/Simulink. An experimental platform based on dSPACE is built. The simulation and experimental results show that this novel PMSM controller can effectively suppress the system chattering and improve the dynamic performance and robustness of the system.

Distributed cooperative cruise control for high‐speed trains with multi‐objective optimization

This paper proposes a novel cooperative cruise control strategy to jointly optimize the energy consumption and ride comfort for multiple high-speed trains. The cooperative control strategy is constructed by combining the consensus algorithm and potential function to achieve the synchronization of train speed and keep a safe tracking interval. A multi-objective optimal function of multiple high-speed trains is constituted of cruise following error, energy consumption and ride comfort. The non-dominated quick sorting algorithm (NSGA-II) is used to find the global Pareto-optimal solutions to obtain the optimal cooperative control gains, which achieve the optimal trade-offs between energy consumption and riding comfort for high-speed trains. The asymptotic stability of the proposed control strategy is proved strictly. The simulation results verify that the proposed control strategy can effectively reduce energy consumption and improve the riding comfort simultaneously when compared with existing methods.