Synchronous Speed Research Articles

The synchronization, stability and stochastic resonance of stochastic global coupled system

In this paper, we aim at a global coupled system influenced by a multiplicative dichotomous noise and an additive Gaussian white noise. Since the analysis of the synchronization and stability is important to a coupled system, and there is little general method to analyze them. We provide methods to derive the synchronization and stability of particles in the system. Guaranteed by the synchronization and stability, we obtain the analytic expression of each particle’s average displacement. To verify our results, we use stochastic Taylor expansion to derive numerical iterative expressions of the displacements of particles. As for numerical simulations, we find that the numerical solutions match the analytical solutions, and we display the synchronization speed of particles, the stable region of noise intensity, resonance areas and the output amplitude gain with respect to various parameters of the system. We find that the phenomenon of stochastic resonance occurs if and only if the parameters are situated in the resonance area.

Numerical Analysis of Francis Turbine being operated in variable speed from sediment erosion perspective

Sediment erosion in hydro turbines is one of the most daunting reasons incurring huge losses to power plant owners located in the Hindu Kush Himalayan region. Repetitive repair and maintenance of runners of Francis turbines installed in such power plants have been one of the major contributor to these losses. There is no measure of how much these power plant owners have lost due to reduction in efficiency brought about by the eroded surfaces of runners. Amidst several optimizations performed in changing the runner design, this study has been conducted to study the applicability of the pre-existing designs being operated in variable speed conditions, irrespective of its practical difficulties. Numerical simulations have been performed to determine the sediment erosion of the runners at different operating conditions. In addition to the guide vane angles, and the amount of sediment injected into the system; which is parametrized as a function of the guide vane angles; rotational speed of the runner has also been varied. Complete efficiency hill diagram and sediment erosion hill diagram have been developed to analyse the efficiency and sediment erosion at several operating conditions. Finally a comparison of the variations in efficiency and sediment erosion upon operating the turbine in synchronous speed and variable speed modes have been shown. Basically, the efficiency of the turbine and sediment erosion on blade surface can be increased and decreased respectively, at off design conditions by operating the turbine in variable speed.

Modelling and Analysis of Salient-Pole Rotor Interior Permanent Magnet Synchronous Motor for Oil and Gas Pump Applications

This paper presents the design and dynamic simulation of a line-start, three-phase Interior Permanent Magnet Synchronous Motor (IPMSM) intended for pump applications in the oil and gas industry. The problem addressed in this paper pertains to the replacement of an existing induction motor (IM) in an oil and gas pump station with a more efficient and controllable solution, the IPMSM since IMs are known to be less efficient and IPMSM is easier to control. The chosen motor type employs a traditional salient-pole rotor with cage windings, known for its line-start capability, making it a feasible choice for constant-speed and pump applications. The dynamic simulation of the proposed IPMSM is carried out using MATLAB/Simulink, focusing on fundamental harmonic analysis in direct-phase variables. The results demonstrate rapid startup to synchronous speed with minor deviations effectively dampened by the rotor's damper windings. Torque characteristics exhibit some pulsations caused by magneto-motive force (MMF) harmonics; a phenomenon captured by Finite Element Analysis (FEA). The performance results show that the proposed IPMSM with a salient-pole rotor is viable and a promising replacement for induction motors in oil and gas pump stations.

Performing Wind System with Rectifier with Near Sinusoidal Input Current

The RNSIC-1 (rectifier with near sinusoidal input currents converter), is the foundation of a wind generator system that is presented. The three inductances that make up a traditional RNSIC–1 converter are eliminated in the proposed arrangement, and the SCIG generator's leakage inductances fill their place. This is what makes it new. The wind system's role in the load currents is discussed. Lower power losses, smaller harmonic input currents, fewer EMI issues, excellent dependability, and cheaper costs are characteristics of the new wind system. This new wind system could be used for partial variable speed wind turbines (usually 70% to 100% synchronous speed) and lower hydro connector squirrel cage induction generators (SCIG).

Research on coupling control of multiple permanent magnet synchronous motors based on NAISMC and SMDO.

The synchronous control system of multi-permanent magnet motor has the characteristics of many parameter variables and mutual coupling. The use of sliding mode control to optimize the parameters in the multi-permanent magnet motor system not only ensures the stability of the system operation, but also improves the control accuracy of the system, which is of great importance in practical applications. Based on this background, the study combines the new adaptive integral sliding mode control (NAISMC) with the improved sliding-mode disturbance observer (SMDO) and uses it for the multi-permanent magnet synchronous motor (MPMSM). In NAISMC, the controller updates and adjusts the parameters of the controller using an adaptive algorithm according to the state of the system and the error signals, which further improves the stability and robustness of the system. SMDO utilizes the principle of the sliding-mode observer to estimate the disturbance of the system, and eliminates the effect of the disturbance on the system by introducing a compensation term. The sliding mode observer calculates the disturbance estimate by comparing the difference between the actual and the estimated outputs. The disturbance estimate is finally used to generate the corresponding compensation signal to eliminate or minimize the effect of the disturbance on the system. NAISMC is combined with SMDO and used in the deviation coupling control of MPMSM. The study established a simulation experiment environment in MATLAB, set the simulation time to 0.4s, and the rated speed of the motor to 1000r/min. The improved sliding mode control scheme is tested, and the results show that the motor output speed, tracking error and electromagnetic torque variation under the improved sliding mode control scheme are smaller than those under the traditional sliding mode control scheme. Under the same simulation conditions, the multi-motor speed synchronization error under the improved sliding mode control scheme is around 0r/min, and its error value is close to 0, so the control effect is higher. In conclusion, the optimization scheme proposed in this study can effectively improve the stability and control accuracy of the multi-motor system.

Fast Kalman filter synchronization algorithm for cooperative synchronization in time sensitive networks

Clock synchronization is crucial in time-sensitive networks (TSN) to ensure the normal operation of devices. However, traditional synchronization techniques face challenges such as the accumulation of synchronization errors over multiple hops and slow synchronization speed, which hinder the development of large-scale and multi-hop TSN. In this paper, we propose a cooperative synchronization scheme based on two-way timestamp exchange to reduce error accumulation and enable synchronization information exchange between any node in the network and the reference node. Moreover, we develop a fast Kalman filter (FKF) algorithm to estimate clock offset and clock skew. To reduce time complexity, we replace the calculation of gain matrices with extremely high dimension with a small matrix based on the randomization matrix approximation in the updating phase of the Kalman Filter. Simulation results show that the proposed method significantly reduces synchronization complexity without sacrificing clock synchronization accuracy, making it highly promising for future TSN deployments.

Rotating blade vibration parameter identification based on genetic algorithm

In this paper, aiming at the identification of blade vibration parameters such as constant speed synchronization, constant speed asynchronous, and variable speed synchronization, the simulation platform Simulink is used to model the blade vibration system, and the blade tip timing vibration measurement system model is constructed. A method of blade vibration parameter identification based on genetic algorithm is proposed, and numerical simulation and experimental verification are carried out. The results show that the parameter identification of blade vibration by genetic algorithm has high accuracy and strong anti-noise interference ability. The influence of key parameters on the identification of blade vibration parameters is studied. For the constant speed synchronous and constant speed asynchronous vibration of the blade, the angle between the sensors should not be an integral multiple of 2π as far as possible, and the larger DR (Distribution Range) value should be guaranteed. The higher the frequency doubling of blade vibration, the more sensors are needed. For the variable speed synchronous vibration of the blade, the frequency doubling is greater than the influence of the sensor layout on the parameter identification results, but the number of sensors is too small, which will seriously affect the identification accuracy of the frequency doubling. Aiming at the blade vibration test, a blade vibration tester is designed. The blade variable speed synchronous vibration test is carried out by using the strain gauge method and the tip timing method. The measurement results of the strain gauge method are basically consistent with the measurement results based on the genetic algorithm and the tip timing.

Learning-based sliding mode synchronization for fractional-order Hindmarsh-Rose neuronal models with deterministic learning.

In recent years, extensive research has been conducted on the synchronous behavior of neural networks. It is found that the synchronization ability of neurons is related to the performance of signal reception and transmission between neurons, which in turn affects the function of the organism. However, most of the existing synchronization methods are faced with two difficulties, one is the structural parameter dependency, which limits the promotion and application of synchronous methods in practical problems. The other is the limited adaptability, that is, even when faced with the same control tasks, for most of the existing control methods, the control parameters still need to be retrained. To this end, the present study investigates the synchronization problem of the fractional-order HindmarshRose (FOHR) neuronal models in unknown dynamic environment. Inspired by the human experience of knowledge acquiring, memorizing, and application, a learning-based sliding mode control algorithm is proposed by using the deterministic learning (DL) mechanism. Firstly, the unknown dynamics of the FOHR system under unknown dynamic environment is locally accurately identified and stored in the form of constant weight neural networks through deterministic learning without dependency of the system parameters. Then, based on the identified and stored system dynamics, the model-based and relearning-based sliding mode controller are designed for similar as well as new synchronization tasks, respectively. The synchronization process can be started quickly by recalling the empirical dynamics of neurons. Therefore, fast synchronization effect is achieved by reducing the online computing time. In addition, because of the convergence of the identification and synchronization process, the control experience can be constantly replenished and stored for reutilization, so as to improve the synchronization speed and accuracy continuously. The thought of this article will also bring inspiration to the related research in other fields.

An Integrated Control Approach for Shifting Process of Single-Axis Parallel Hybrid Electric Vehicle with a Multi-Speed AMT Gearbox

When a single-axis parallel hybrid electric vehicle (HEV) equipped with a multi-speed AMT gearbox is in its shifting process, the superposition of dynamic characteristics of multiple power sources and the intervention and withdrawal of AMT transmissions can easily cause significant vehicle longitudinal jerk. To achieve rapid and smooth output changes during the shifting process, this paper proposes an integrated multi-stage robust shifting control method for a single-axis parallel hybrid electric vehicles with a multi-speed AMT gearbox. First, models of key driveline components are constructed, and the shifting process is divided into five stages to provide a clear description of the control problem. Subsequently, we reproduce an integrated multistage robust control method to achieve favorable switching performance and control robustness under external disturbances. We propose a data-driven model predictive control strategy based on additional constraints in the torque unloading and recovery phases. Simultaneously, we present a joint control algorithm that integrates the optimal control and disturbance suppression in the speed synchronization phase. In addition, we develop a sliding mode auto-disturbance rejection control algorithm to achieve accurate position tracking of the shift actuator in the pickup and engage phases. Finally, simulations and bench tests are carried out to verify the effectiveness of the robust control method under different driving conditions. The results demonstrate that the proposed control method can not only coordinate the torque across different power sources and clutch while minimizing vehicle longitudinal jerk, shift time, and friction work, but also provides apparent robustness to model uncertainties and external disturbance. Therefore, the proposed method may offer a theoretical reference for the actual vehicle controller during shifting.

Phase Compensation Factor-Based Low Frequency Crossing for Sensorless Induction Motor Drives With Changing Loads

This article deals with speed observation methods for sensorless induction motor drives (SIMD). The speed observability of SIMD near zero stator frequency is a well-known concern. Using adaptive magnetizing current, existing methods are capable of crossing the zero-stator-frequency line, but still limited to constant load conditions. To solve these problems, this paper presents a phase compensation factor-based low frequency crossing method with changing loads (PCF-LFCCL) to realize low frequency crossing process with decreased overcurrent and speed spikes. Firstly, the influence of load variations is studied finely, the LFCCL method is proposed with adaptive magnetizing current. Secondly, the torque output capacity analysis is given and illustrated. On this basis, the synchronous speed limit can be adopted properly. Thirdly, a generalized current model is developed for SIMD. The model reveals the phase delay phenomenon between magnetizing current reference and actual torque current, which can lead to speed spikes and overcurrent. To address this issue, a phase compensation factor (PCF) based method is developed by reconstructing compensation values to correct the torque current. Finally, comparative experiments are presented to validate the PCF-LFCCL method, including stator resistance error test for parameter robustness.

Time and energy costs for synchronization of multi-layer networks

In this paper, the finite-time and fixed-time synchronization problems of multi-layer networks are studied. In order to achieve the synchronization, two novel switching controllers are proposed and the effectiveness is verified by the Lyapunov stability theory. Moreover, the upper bound of time and energy costs are estimated. Specifically, the results show that increasing the synchronization speed will inevitably increase the consumption of control energy, which means there is a trade-off between time and energy costs. Therefore, an index function is given to quantify the time and energy costs, and it is found that adjusting the parameters can minimize the total cost. Finally, the theoretical results are verified by some numerical simulations.

基于 Arduino 的小型蔬菜播种机远程控制系统设计与性能试验

Facilities greenhouses are relatively narrow and airtight, and the machine operation turns frequently. The existing vegetable seeders is supported by manual hand, and the straightness of operation is poor, Turning around is time-consuming and laborious. This paper designs a remote control system of small vegetable seeder based on Arduino microcontroller, the Arduino single-chip microcomputer remote control technology, multi-motor synchronous drive technology, differential-electric push rod combined with lifting and steering control and other methods are adopted, Through remote control, the forward, speed regulation, lifting of the whole machine and field line change and steering of the seeder during vegetable sowing are realized. The differential steering model and brushless motor speed control model are established, and the android human-computer interaction APP is designed to realize the remote precise control of vegetable seeder. The performance test of the accuracy of the control system was carried out with the accuracy and steering accuracy of the seeder. The results showed that : under the condition of medium speed and medium and low speed operation, the seeding level of vegetable seeder is the most stable and reliable, the speed deviation rate of the seeder is 1.59 %, after starting the drive motor for 2s, the actual speed is close to the target speed, differential steering is relatively accurate, the qualified rate of steering is more than 89.8 %, the synchronous speed error of the lifting mechanism tends to be stable.This study can provide reference for the development of intelligent equipment for facility agriculture.

Generalized Data-Driven Model-Free Predictive Control for Electrical Drive Systems

The performance of model predictive control has a strong correlation to the precision of the physical parameters of the plant, and these parameters are hard to determine since they are continuously changing during the operation process. To fully eliminate the influence of the physical parameters and enhance robustness, a model-free predictive control is proposed in this article to suit the electrical drive systems. The plant model is designed as several discrete-time transfer functions used to decouple the input and output signals and to describe their relationships, and the coefficients of these functions are online designed based on the recursive least square algorithm. An observer is designed to obtain accurately sampled current components considering the delays. The proposed method is applied to a permanent magnet synchronous motor speed control system as the stator current controller, and the simulation and experimental results show the advantages of the improved dynamics, stator current quality, and robustness compared with the conventional model-free predictive current control strategy.

Active disturbance rejection control with fractional-order model-aided extended state observer

Increasing the observer bandwidth of the extended state observer (ESO) can significantly enhance the disturbance rejection performance of the active disturbance rejection control (ADRC). However, a large observer bandwidth can also amplify the noise and degrade the control quality. This study proposes a novel fractional-order ADRC (FOADRC) approach. A fractional-order model-aided extended state observer (FOMESO) is designed by leveraging available plant information. Under a given observer bandwidth, the disturbance estimation performance of FOMESO is improved, while noise sensitivity is not aggravated. Additionally, FOMESO transforms a typical second-order plant into a fractional-order double-integrator model, reducing the phase lag to below 180∘. Consequently, the derivative component, which is sensitive to noise, is unnecessary in the feedback controller. Simulation and comprehensive comparisons demonstrate that the proposed FOADRC scheme outperforms the traditional ADRC in tracking, noise sensitivity, disturbance rejection, and stability. Furthermore, the proposed FOADRC approach is robust to plant parameter variations. The proposed method is validated through experiments on a permanent magnet synchronous motor speed servo system, confirming its superiority and effectiveness.

Rotor Winding Design and Standalone Operation Research of High Natural Synchronous Speed Brushless Doubly-Fed Generator Based on Differential Modulation

Differential Modulation Brushless Doubly-fed Machine (DMBDFM) can achieve smaller equivalent pole-pair number, which broaden the operating range and application of Brushless Doubly-fed Machine (BDFM). However, the existing basic theory of BDFM can not be directly applied to DMBDFM, and the design method of the modulated rotor with different combination of pole-pair numbers (PPN) is not complete. Therefore, in order to achieve the highest natural synchronous speed(<i>n</i>_s) of BDFM at power system frequency, the rotor winding of 3&#x002F;2 pole pairs is designed in this paper. Then the test prototype is developed with the designed rotor scheme and the relevant parameters are given. The validity of the rotor design scheme is verified by finite element simulation and test results.

Design and Analysis of a Pneumatic Automatic Compensation System for Miss-Seeding Based on Speed Synchronization

In order to solve the problems of poor seed filling performance and the low compensation accuracy of large- and medium-sized missed seeding compensation devices under medium- to high-speed conditions, a pneumatic missed seeding automatic compensation system based on speed synchronization was designed. The key structure and parameters in terms of the seed metering plate and seed feeding arm were determined by theoretical analysis. A universal compensation control system for single-seed missed seeding and continuous missed seeding was designed. With regards to exploring the working performance, some relevant bench tests were carried out, with Zhengdan-958 corn seeds and Zhonghuang-37 soybean seeds serving as the test objects. First of all, a single-factor test was conducted to determine the optimal level ranges of the factors that influence seed filling performance, such as suction hole diameter, seed stirring bar thickness, and negative pressure. The test indicators were qualified seed filling rate, multiple seed filling rate, and missed seed filling rate. Next, the Box–Behnken design test was executed to explore to the influence law of each test indicator on corn seed filling performance. Then, the parameter optimization module was applied to achieve the best combination of operating parameters for the test factors. The optimal combination of parameters was a suction hole diameter of 5.3 mm, seed stirring bar thickness of 2.9 mm, and negative pressure of 4.1 kPa. Based on the optimal combination, a verification test of corn seed filling performance was performed, and the corresponding evaluation indexes were a qualified seed filling rate of 95.46%, multiple seed filling rate of 2.47%, and missed seed filling rate of 2.07%. Lastly, a seed feeding performance verification test was employed with the seeding speed as the impact factor to verify the compensation accuracy of single-seed missed seeding and continuous missed seeding compensation. The results of the verification test indicate that, for corn seeds, when the seeding speed falls within the range of 8 to 12 km/h, the effective single-seed feeding rate exceeds 88%, the average single-seed feeding time is less than 0.18 s, the qualified seed feeding rate is higher than 90%, the multiple seed feeding rate is lower than 3%, and the missed seed feeding rate is below 7%. For soybean seeds, the effective single-seed feeding rate is higher than 85%, the average single-seed feeding time is less than 0.17 s, the qualified seed feeding rate exceeds 86%, the multiple seed feeding rate is less than 4%, and the missed seed feeding rate is below 10%. This system meets the agronomic requirements for the automatic compensation of missed seeding with respect to large- and medium-sized precision seeders, which could help to improve the operational performance of seeding machines.

Speed Synchronization Control of Dual-SRM Drive With ISMC-Based Cross-Coupling Control Strategy

To improve the speed synchronization performance of dual switched reluctance motor (SRM) drive with traditional sliding mode control (TSMC), the improved sliding mode control (ISMC) based cross-coupling control strategy is proposed. Firstly, the overall control structure of the dual-SRM drive is represented. Secondly, the state variable is introduced to reduce the torque fluctuation and adjustment time of the dynamic process of each SRM drive in the system based on the traditional sliding surface and sliding mode reaching law. The adaptive law is introduced into the sliding mode controller to avoid the load torque observation. Thirdly, the ISMC-based cross-coupling control method for the speed synchronization of the dual-SRM drive is designed. The novel sliding surface is proposed considering the speed synchronization deviation. The novel sliding mode reaching law is represented by introducing the state variables. Then the ISMC-based cross-coupling control method is realized for speed synchronization. The stability is proved by Lyapunov function. Simulations and experiments are implemented to verify the effectiveness of the proposed method.

Equivalent simulation test method for internal ballistics of fuze reserve chemical power source with adjustable combined overload and rotational speed

To solve the problem that the test environment is not equivalent to the actual use environment in the step-by-step test method of fuze reserve chemical power supply, this paper proposes a fuze reserve chemical power source with an adjustable combination of overload and rotational speed by building a test platform to realize the synchronization of overload and rotational speed. In this method, compressed air and a rotary table were used to generate the flight power and rotational speed of the test tool, and then the overload and centrifugal force were controlled and loaded by the tool launcher and damping generator, and finally, the non-destructive recovery of the test tool was realized by the slow release mechanism. The test results showed that using the synchronous realization and controllable combination of overload and rotation, the internal ballistic equivalent simulation method could generate 3 000g ~ 30 000g overload, and the rotational speed of 0 ~ 18 000rpm could be synchronously controlled. The test results of the fuze power supply showed that the combination of overload and rotational speed could be controlled by this method. Under the same conditions, the overload repeatability reaches 95.5%, the rotational speed stability reaches 99.7%, and the equivalence with the medium and large-caliber inner ballistic environment is 91%. Therefore, through the test, the basic equivalent simulation of the ballistic environment in the fuze power supply has been realized.

Investigations of Spoilers to Mitigate Columnar Vortices in Propeller Turbines at Speed-No-Load Based On Steady and Unsteady Flow Simulations

Abstract With the introduction of an ever-larger share of renewable but intermittent energy sources on electrical grids, hydraulic turbines are more often used as network stabilizers. In such a role, they are generally operated in off-design operations like speed-no-load (SNL). No energy is extracted from the flow at SNL operation, but the runner rotates at the synchronous speed linked to the electrical grid. The flow inside the runner of low-head turbines operating at SNL is often dominated by a columnar vortex array that may induce damaging pressure fluctuations. This paper presents the study of a control device to mitigate those vortices. At SNL, the small guide vane opening leads to a high swirl in the runner generating secondary flows such as columnar vortices and backflows. The proposed concept is to move SNL operation toward a higher guide vane opening and hence lower swirl, preventing the formation of a columnar vortex array. Lowering the input swirl of SNL is accomplished by opening up the guide vanes while using a control device to limit the discharge. The control device, like a spoiler on an aircraft wing, is introduced on the guide vanes to generate added head losses, significantly decreasing the discharge. This paper compares the hydrodynamics of the flow in a propeller turbine with different spoiler geometries. The study is based on both RANS and URANS flow simulations. It highlights how such devices can successfully mitigate columnar vortices and their associated pressure fluctuations on runner blades.

3상 유도기의 전동 운전과 발전 운전 모드에서의 무효전력 특성 분석

Induction machines can be operated as motors or generators near synchronous speed and it must be continuously receive the reactive power which is required for magnetization from the power supply side to maintain the rotating magnetic field regardless of the operation modes. If an induction machine with the same output capacity is operated as a motor or generator, the magnitude of the active power in each operation mode is different each other because the input and output are opposite to each other. When the active power changes, the reactive power also fluctuates, but the reactive power is slightly higher when operated as generator than when operated as motor. This is the reason why the power factor is slightly lower when the induction machine is operated as a generator than when it is operated as a motor. In this study, the magnitude of reactive power were calculated at each operation modes and analyzed how the ratio of reactive power changes when operated as a motor and as a generator for each capacity of the induction machine. The results are expected to be used as design reference data for selecting the optimal capacity of capacitors to improve the power factor in motor and generator operation of induction machines in the future.