Torque Pulsations Research Articles

Multi-Objective Optimization Strategy for Commercial Vehicle Permanent Magnet Water Pump Motor Based on Improved Sparrow Algorithm

In order to achieve multi-objective optimization for a permanent magnet water pump motor in heavy commercial vehicles, we propose a strategy based on response-surface methodology and the improved sparrow algorithm (CGE-SSA). Firstly, the output capacity of the pump during actual operation was tested with an experimental bench to determine the design parameters of the motor, and then its modeling was completed using Ansys Maxwell 2022r2 software. Secondly, the response-surface model was established by taking the parameters of permanent magnet width, rib width, and slot width as optimization parameters and the output torque (Ta), torque ripple (Tr), and back electromotive force (EMF) amplitude as optimization objectives. Meanwhile, three methods—namely, circular sinusoidal chaotic mapping, improved golden sinusoidal strategy, and adaptive weight coefficients—were used to improve the convergence speed and accuracy of the sparrow search algorithm (SSA). Finally, the multi-objective optimization of the permanent magnet synchronous motor was completed using the improved sparrow algorithm. A comparative analysis of the motor’s output before and after optimization showed that the torque pulsation and reverse electromotive force of the motor were significantly improved after optimization.

Electromagnetic performance analysis of a novel radial compound differential field-modulated magnetic gears

Purpose The purpose of this study is to propose a new magnetic gearing device and the proposed transmission model can be applied in the field of wind power and wave energy generation gearboxes. Design/methodology/approach A novel radial differential field-modulated two-stage magnetic gear is introduced, using a unique radial differential linkage to integrate two single-stage magnetic gears. This design incorporates a magnetic isolation ring to enhance transmission efficiency by minimizing magnetic interference and preventing power circulation. The two-stage modulating ring rotor operates synchronously via a connecting bridge, ensuring system stability and efficiency. This configuration not only boosts the gear ratio but also maintains a compact structure, improving power density and efficiency. Leveraging the magnetic field modulation and differential transmission, a finite element model of this gear is developed and its electromagnetic performance is analyzed. Findings The torque density of the new radial differential field-modulated two-stage magnetic gear has increased by 44.97% compared to the traditional tandem two-stage magnetic gear. It achieves a high transmission ratio of 64 and maintains comparable power density, indicating strong torque transfer capabilities suitable for low-speed, high-torque applications. During steady-state operation, the torque pulsation difference between the two stages is minimal, ensuring stable working torque. Social implications This research not only propels the forefront of magnetic gear technology through heightened efficiency and streamlined design but also bears profound societal significance in fostering sustainable energy paradigms. By facilitating superior energy conversion efficiencies in wind turbines and wave energy converters, it plays a pivotal role in mitigating carbon emissions and accelerating the global pivot towards cleaner, renewable energy landscapes. Originality/value A magnetic gear transmission device is proposed, which can achieve high power density and large transmission ratio at the same time, and this study provides a useful reference for the design optimization of new high-performance multistage magnetic gears.

Model Predictive Control of Aero-Mechanical Actuators with Consideration of Gear Backlash and Friction Compensation

To address the issues of low positional accuracy and significant torque pulsation caused by gear backlash and nonlinear friction in the mechanical transmission mechanism of aeronautical flap electromechanical actuators, we propose a model predictive control method for flap electromechanical actuator considering gear backlash and friction compensation. Firstly, we model the gear backlash in the electromechanical actuator’s mechanical transmission mechanism and design a corresponding torque current compensation method using a simplified dead zone model. Secondly, the LuGre compensation friction model is introduced, and a friction torque current compensation method is developed to address the nonlinear friction torque generated during system operation. Finally, the proposed current compensation strategies are employed to mitigate the adverse effects of gear backlash and nonlinear friction on system control performance. The simulation results demonstrate that the proposed method enhances position tracking accuracy, reduces torque pulsation, and significantly improves the overall control performance of the system.

An Improved Collaborative Control Scheme to Resist Grid Voltage Unbalance for BDFG-Based Wind Turbine

This article presents an improved collaborative control to resist grid voltage unbalance for brushless doubly fed generator (BDFG)-based wind turbine (BDFGWT). The mathematical model of grid-connected BDFG including machine side converter (MSC) and grid side converter (GSC) in the αβ reference frame during unbalanced grid voltage condition is established. On this base, the improved collaborative control between MSC and GSC is presented. Under the control, the control objective of the whole BDFGWT system, including canceling the pulsations of electromagnetic torque and the unbalance of BDFGWT’s total currents, pulsations of BDFGWT’s total powers are capable of being realized; therefore, the control capability of BDFGWT to resist unbalanced grid voltage is greatly improved. Moreover, improved single-loop current controllers adopting PR regulators are proposed for both MSC and GSC where the sequence extractions for both MSC and GSC currents are not needed any more, and hence the proposed control is much simpler. In addition, the transient characteristics are also improved. Moreover, in order to achieve the decoupling control of current and average power, current controller also adopts the feedforward control approach. Case studies for a two MW BDFGWT system are implemented, and the results verify that the presented control is capable of effectively improving the control capability for BDFGWT to resist grid voltage unbalance and exhibit good stable and dynamic control performances.

Numerical Study on Valve Closing Criteria during Pump-turbine Start-up on Pump Mode

Abstract Vibrations of exhaust pipes have been observed in some hydropower stations during the exhaust process of pump-turbine start-up on pump mode due to water ingress into the pipes. It may have a safety risk for the pump-turbine start-up process when exhaust pipes are operating under the compressed air-water two phase flow. Since the numerical simulation researches about pump start-up process have been rarely reported and the development of flow field in exhaust pipe is lack of quantitative cognition, it calls for an urgent need to supplement related works. In this paper, the transient full-channel two-phase numerical simulation research on the pump mode return water exhaust process of a pumped power station is carried out by Reynolds-Averaged Navier-Stokes approach. This work put emphasis on the characteristics of cone water level, runner torque and air speed in exhaust pipes after the compressed air released from the runner chamber. Then development laws and relationship with the exhaust valve closing timing are analysed and concluded. Results show that the cone water level, runner torque and air speed pulsation signal of exhaust pipes can be used as exhaust valve closing criteria, and the third criterion has the largest time margin.

Research on the induced vibration force characteristics of lateral propulsion propeller

Abstract This article conducts unsteady numerical calculations on lateral thrusters under arrival conditions, revealing the induced unsteady force characteristics under the interference between lateral thrusters and pod packages. The calculation results show that the lateral force and torque of the lateral propeller point towards the bow of the ship, and the main characteristic frequencies of pressure pulsation are blade frequency and its harmonics; The thrust and torque pulsation of the side thrusters on the bow side of the ship have maximum values; The bottom of the lateral thrust channel exhibits stronger pressure pulsation compared to other positions. The calculation results of this article determine the position and characterization form of the excitation force of the lateral thruster, providing a basis for the design of low-noise lateral thrusters.

Simultaneous Suppression of Torque Pulsation and Electromagnetic Vibration of a Spoke-Type PM Motor by Space-Time Flux Density Harmonics Optimization

Simultaneous Suppression of Torque Pulsation and Electromagnetic Vibration of a Spoke-Type PM Motor by Space-Time Flux Density Harmonics Optimization

FRT capability improvement of a wind power system using support vector regression and deep neural network models

ABSTRACT The increasing energy demand and environmental conditions have led many countries to favor renewable energy,such as wind and solar,over conventional power plants. As per the Central Electricity Authority (CEA), India’s wind power capacity has grown substantially, reaching 45,154 MW in 2023, from 22,465 MW in 2013. However, integrating wind generators to an existing power system network can reduce transient stability during faults. To prevent wind turbine disconnection during faults, Indian grid code authorities mandate Fault Ride Through (FRT) or Low Voltage Ride Through (LVRT) capability for wind turbines. This paper proposes Dynamic Voltage Restorer (DVR) for enhancing the FRT capability of a constant speed wind turbine. Analysis and simulation are done on a fixed speed wind turbine employing Squirrel Cage Induction Generator (SCIG) under balanced and unbalanced voltage sags. Performance of DVR with two Artificial Intelligence-based controllers, Support Vector Machines(SVM) Regression Model Based Supervised Machine Learning algorithm, and Deep Neural Network (DNN) controller, is analysed and compared. The SVM Regression algorithm, achieves 100% voltage sag compensation under unbalanced voltage sags, reduces torque pulsations to 25% and maintains rotor speed at rated values, enabling the turbine to remain connected to the grid. Additionally it reduces Total Harmonic Distortion to 2%.

Computational investigations of Ka-226T helicopter coaxial rotor aerodynamics in the vortex ring state

The vortex ring states are observed when the rotor is flowed at positive angles of attack. For the main rotor, these conditions are realized during a steep descent of the helicopter at low speeds. The rotor vortex ring states are affected by significant phenomena related to the behavior of its aerodynamics, including negative phenomena. The latter is, firstly, referred to decrease in rotor thrust, increase in the required power, pulsations of thrust and torque, unsteady flapping blade motion, etc. In terms of helicopter piloting, it means a sharp loss of altitude, increase in the control force, a high level of vibration, defocusing attenuation of rotor spinning cone, as well as controllability deterioration. All these factors determine the relevance of research on these modes and the importance of solving a problem of defining their boundaries. Recently, due to the rapid development of computer technologies and computational models, it has become practical to perform numerical research of the rotor aerodynamics in vortex ring states. The paper presents the study results of Ka-226T helicopter coaxial rotor aerodynamics in steep descent modes in the field of vortex ring states. The angles of rotor attack αВ = 90...30° and the range of vertical descent velocities Vу = 0...26 m/s are considered. The original nonlinear bladed vortex model of the rotor developed at the Moscow Aviation Institute (MAI) was used. The total and distributed aerodynamic rotor characteristics were calculated. The shapes of the vortex wake and the rotor flow patterns were analyzed. The boundaries of the vortex ring states in velocity coordinates “Vx − Vу” were constructed according to various criteria reflecting the known features of these states. The results obtained significantly complement the existing experience of experimental and numerical research in this field.

Effect of number of blades on performance and wake recovery for a vertical axis helical hydrokinetic turbine

Hydrokinetic turbine provides a viable option for tapping energy from free-flowing water, making it an attractive contributor to the renewable power landscape. This study investigates the effects of blade number and solidity on the performance and wake recovery of a small-scale vertical axis helical hydrokinetic turbine under different tip speed ratios and inflow velocities. Computational fluid dynamics simulations are employed, followed by experimental validation, to analyze power, self-start, torque pulsations, velocity deficit and flow field characteristics. The highest power coefficient is found to be 0.24 for a 4-bladed rotor with 0.3 solidity at a tip speed ratio of 1.0 and inflow velocity of 1.0 m/s. The performance of the studied rotors decreases as inflow velocity increases due to high turbulence experienced, resulting in flow separation. The self-start characteristics are shown to improve with solidity, while torque pulsations are greatly diminished with the increase in number of blades. The wake analysis results show that the velocity deficit and turbulence intensity increase significantly as the number of blades increases. Moreover, the time-averaged streamwise velocity values are observed to reach almost 95 % at a downstream distance of 19–25 times the rotor diameter for investigated rotors.

Pulsations of the Electromagnetic Torque of Synchronous Motors Excited by Permanent Magnets of Slotless Design

Pulsations of the Electromagnetic Torque of Synchronous Motors Excited by Permanent Magnets of Slotless Design

Direct torque motor control technology based on NPC three-level SVPWM

This paper introduces a direct torque control technology based on NPC three-level SVPWM. It uses the Matlab platform to build a simulation model. It verifies the ideal waveform of the torque, magnetic chain, and current of the NPC-SVPWM direct torque control system under high speed and low speed with no load and load. This technique improves the waveform of the stator current and stator magnetic chain and solves the problem of the switching frequency not being fixed. Through this technique, it not only retains the robustness of the direct torque technique to the parameter change, but also effectively reduces the torque pulsation.

A Proportional-Integral-Resonant Current Control Strategy for a Wind-Driven Brushless Doubly Fed Generator during Network Unbalance

This article proposes a proportional-integral-resonant (PIR) current control strategy for a wind-driven brushless doubly fed generator (WDBDFG) during network unbalance. Firstly, four control objectives of WDBDFG, including eliminating unbalanced currents of power winding (PW), pulsations of control winding (CW) currents, torque, and PW power, are discussed and different from current controls in which the references to PW currents were computed; the CW current references are derived here. Then, an improved CW current controller using a PIR controller is proposed to achieve different control objectives. In contrast with current controls, CW currents are not involved with sequence extraction in the proposed control and can be totally regulated only in a positive synchronous reference frame. Hence, the system control structure is greatly simplified, and dynamic characteristics are improved. Furthermore, in order to obtain completely decoupled control of current and average power, feedforward control, considering all the couplings and perturbances, is also applied in CW current loops. Simulation results for a 2 MW grid-connected WDBDFG show that the proposed control is capable of achieving four control objectives, including canceling CW current distortion, PW current unbalance, pulsations of PW active power or pulsations of reactive power, and machine torque. Its dynamic process is much more smoothly and quickly than that of current controls, and therefore the proposed control has better dynamic control characteristics during network unbalance.

Torque System Modeling and Electromagnetic Coupling Characteristics Analysis of a Midpoint Injection Type Bearingless Permanent Synchronous Magnet Motor

Taking the Midpoint Injection type Bearingless Permanent Magnet Synchronous Motor (MPI-BL-PMSM) as an object, to solve its problems of large torque pulsation and insufficient suspension force when adopting Midpoint Suspension Current Unilateral Injection (MPSC-UI), a Midpoint Suspension Current Bilateral Injection (MPSC-BI) solution is proposed. Based on the half-winding structure of MPI-BL-PMSM, and from the electromechanical energy conversion principle, the torque model for MPSC-BI solution is established. On this basis, the torque model for MPSC-UI method was derived. The correctness of the established torque mathematical models based on half-winding structure was verified through the finite element method (FEM), and the “dual-frequency” electromagnetic coupling characteristics of suspension current on electromagnetic torque were compared and analyzed from the perspectives of theoretical model and FEM simulation. The results indicate that the MPSC-BI method can effectively suppress or avoid the torque pulsation coupled by suspension current and can obtain about 1-time increase of controllable suspension force; the advantages of MPSC-BI solution in dynamic torque decoupling characteristics are demonstrated, while the only downside is that the coupling effect of torque current on radial suspension force is slightly greater than that of the MPSC-UI method.

Suppression of Torque Ripple in Switched Reluctance Motors Which is Based on Synchronization Technology

The double salient pole structure of Switched Reluctance Motor (SRM) makes its electromagnetic field exist nonlinear saturation characteristics, resulting in its large torque pulsation in operation, so it is difficult to achieve speed regulation smoothly by traditional control methods. In view of this problem, a sliding mode control strategy which is based on synchronous transmission technology was proposed.Firstly, the basic structure of switched reluctance motor was analyzed, and the mathematical model of mechanical motion of switched reluctance motor was established. Secondly, an improved sliding mode controller which is based on synchronous signal transmission technology was designed by analyzing the reason of large torque ripple of switched reluctance motor, and the stability of the system was proved. Finally, simulation is used to verify the effectiveness of the control strategy.Compared with the traditional PID (Proportional Integral Differential) control algorithm, this control technology not only suppresses the SRM torque ripple effectively , but also makes the sliding mode controller output the precise target electromagnetic torque quickly by increasing the control variables. The results of research indicate that this design can not only restrain the torque ripple effectively, but also adjust the convergence speed and overshoot of the controller by adjusting the design parameters.

Design and optimization of high-speed permanent magnet synchronous motors

In this paper, a 30 kW and 60, 000 r/min high-speed permanent magnet synchronous motor (HSPMSM) was studied. We use the knowledge of motor design to determine the structural dimensions and materials of each part of the machine to create the electromagnetic design of the motor. The FEM model of the motor was created by finite element software, and the no-load and load characteristics for the motor were modeled and analyzed, which verifies the reasonableness of the design of the motor. A genetic algorithm was applied to carry out multi-objective optimization of the motor to obtain the optimized design solution, and the performance of the high-speed motor before and after the optimized design was compared. The simulation results indicate that the rated torque of the motor has been increased through the optimization, while the torque pulsation and the groove torque of the motor have been decreased, which effectively enhances the magnetic characteristic of the designed machine.

Research on a Torque Ripple Suppression Method of Fuzzy Active Disturbance Rejection Control for a Permanent Magnet Synchronous Motor

In order to meet the necessities of steady and protected operation of a permanent magnet synchronous motor (PMSM) in electromechanical pressure gadget aviation beneath complicated working conditions, a three-phase four-arm inverter fuzzy self-disturbance suppression management (Fuzzy-ADRC) approach for PMSM is proposed to suppress the motor torque pulsation beneath complicated working conditions. Firstly, the defects of the common inverter are analyzed, the three-phase four-bridge inverter is changed via the standard three-phase three-bridge inverter, and the present-day harmonic suppression’s overall performance of the three-phase four-bridge inverter is modeled, analyzed, and verified. Secondly, the ADRC and fuzzy management approach is analyzed, the Kalman filter is delivered into the motor pace loop management to enhance the overall performance of ADRC, and then the fuzzy manipulate and ADRC are blended to similarly enhance the torque ripple suppression’s overall performance of the everlasting magnet synchronous motor. Finally, the proposed three-phase four-arm inverter and fuzzy-ADRC approach are combined, and contrasted with the normal three-phase three-arm inverter and ADRC method. The simulation consequences exhibit that the proposed manipulation technique can efficiently suppress the torque ripple of everlasting magnet synchronous motor and has robust reliability.

Control and Analysis of a Hybrid-Rotor Bearingless Switched Reluctance Motor with One-Phase Full-Period Suspension

In the traditional control scheme of a 12/8-pole bearingless switched reluctance motor (BSRM), radial force and torque are usually controlled as a compromise due to the conflict between their effective output areas. Additionally, each phase requires individual power circuits and is excited in turn to produce a continuous levitation force, resulting in high power device requirements and high controller costs. This paper discusses a 12/8-pole single-winding hybrid-rotor bearingless switched reluctance motor (HBSRM) with a hybrid rotor consisting of cylindrical and salient-pole lamination segments. The asymmetric rotor of the HBSRM slightly increases the complexity of its structure and magnetic circuit, but makes it possible to generate the desired radial force at any rotor angular position. A control scheme for the HBSRM is developed to utilize the independent excitation of the four windings in one phase to generate the desired levitation force at any rotor angular position, and it requires only half the number of power circuits used in the conventional control scheme of a 12/8-pole single-winding BSRM. Different from the average torque chosen to be controlled in traditional methods, this scheme directly regulates the instantaneous total torque produced by all excited phases together and presents a current algorithm to optimize the torque contribution of each phase so as to reduce torque pulsation, and the improved performance of this bearingless motor is finally validated by simulation analysis.

RASP methods for achieving low torque pulsation in spoke-type PM motors

RASP methods for achieving low torque pulsation in spoke-type PM motors

Reduction of torque pulsation in ultralight helicopter transmission

Usually, 1–2 seats helicopters use piston engines. One of their disadvantages is a significant torque pulsation on the engine shaft. The main reason for such fluctuations is the change in parameters during the engine’s operating cycle. The purpose of the investigation was to define the pulsation on the helicopter rotor shaft. An additional elastic clutch was used on a single-seat ultralight helicopter Rotorschmiede VA-115 of German firm RS Helikopter GmbH for pulsation dampening. Several flights were performed to assess the pulsation on the shafts. The results of the tests showed that the torque pulsation on the shaft in all modes does not exceed 30 %. This is 10 times less than the pulsation value of 300% specified by the airworthiness standards for this helicopter class.