Torque Characteristic Curve Research Articles

Research on Matching Characteristics of Wind Turbine and Generator for Small H-shaped Vertical Axis Wind Turbine

Based on the small H-shaped vertical axis wind wheel model (NACA0016),a CFD wind wheel model was constructed. Based on the principle of movinggrid, the grid division of the CFD wind wheel model is completed by usingGAMBIT software, and the boundary conditions such as the inlet boundaryand the outlet boundary are set reasonably. Then, the turbulence model andthe couple algorithm are used to carry out transient simulation calculations,and finally the aerodynamic parameter curves of the two-dimensional CFDwind wheel model are obtained. Based on this, the matching characteristicsof the wind turbine and generator of the small H-shaped vertical axis windturbine are studied. The research results show as follows: when the incomingwind speeds change in range of (2 m/s, 12 m/s), and the power character-istic curve and torque characteristic curve of the generator wind wheel arerespectively overlap the best power curve and best torque of the generator,the matching characteristics of the small H-shaped vertical axis wind turbinerotor and generator are optimal, which provides reference for carrying outrelated research.

Inertial Dynamometer for Shell Eco-marathon Engine: Validation

This paper aims to validate the construction of an inertia dynamometer. These types of dynamometers allow easy characterization of internal combustion engines. To validate the dynamometer, tests were carried out with the same engine (Honda GX 160) installed in the UBIAN car and kart, which after calculating the inertia and measuring engine acceleration in each test performed, allows to create the torque characteristic curve from the engine.
 Keywords: Inertia, Dynamometer, Torque, Flywheel, UBIAN

Research on Novel Direct Instantaneous Torque Control Strategy for Switched Reluctance Motor

In order to solve the frequent problem of breaking shaft in the starter/generator system of switched reluctance motor, a novel Direct Instantaneous Torque Control (DITC) is proposed to control the torque ripple in this paper. Instead of the hysteresis controller in traditional DITC, the PWM is introduced to modulate the torque deviation; the optimal switching signal is selected according to the PWM modulation signal and the sector where the rotor position is located. Based on the torque characteristic curves, the torque ripple during commutation period is analyzed and the compensation methods are proposed. Simulation results prove that the compensated PWM-DITC can suppress the torque ripple of switched reluctance motor effectively.

Performance Analysis and Optimization of Liquid-Cooled and Flywheel-Type Eddy Current Retarder

Aiming at the heat fade of the continuous braking and low power density of traditional eddy current retarder (ECR) for heavy vehicles, a new liquid-cooled and flywheel-type eddy current retarder is proposed. The new ECR can keep a low working temperature because of the cooling type. It is assembled between the engine and the clutch, which can effectively improve the braking power density. The transient electromagnetic field of the ECR is solved by the finite-element method, and the braking torque characteristic curve is obtained. The thermal-fluid coupling field is analyzed using the computational fluid dynamics method. Finally, the structure parameters optimization of the rotor tooth is carried out. The braking torque increases by 14.8% and the weight of rotor tooth decreases by 9.5% after optimization. The test results show that the heat fade ratio of the new ECR braking torque is only 8.6%, but that of the traditional ECR is 46.7%.

Experimental Investigation on Unstable Vibration Characteristics of Plates and Drag Torque in Open Multiplate Wet Clutch at High Circumferential Speed

The drag torque caused by the viscous shear in open multiplate wet clutches has been studied in most available literature whose focus is placed on low circumferential speed. However, the drag torque increases drastically in the high circumferential speed range. The underlying physical principles and the influencing factors of the drag torque at high speed are still indeterminate. The present study aims to experimentally investigate the characteristics of the wobbling vibrations of plates and to characterize the effects of average clearance, flow rate of lubricant, shifting condition, and the number of friction interfaces on the drag torque at high circumferential speed. The result of the experiment reveals that the friction plate (FP) starts to wobble periodically at low circumferential speed, though the effect is insignificant. The dominant frequency of plate wobbling movements increases with the input speed. When wobbling vibrations of plates become unstable, the wobble gradually becomes nonlinear. The experiments confirm that the mechanical contacts between plates during the unstable wobbling vibration result in the drag torque rise at high circumferential speed. At high speed, the supplying flow rate of the lubricant influences the drag torque values. The rotation of separator plates (SPs) brings forward the torque rise and makes the drag torque rise smoother. By reducing the number of interfaces, the drag torque rise is delayed and the magnitude becomes smaller. Finally, a four-stage drag torque characteristic curve is illustrated to show the dominant factors of drag torque at different stages.

Electromagnetic properties of cylinder permanent magnet eddy current coupling

This paper focuses on the electromagnetic properties of new cylinder type twelve-pole permanent magnet eddy current coupling. By combining conventional equivalent magnetic charge method and superposition principle, the analytical calculation model of air gap magnetic field distribution for the cyli nder type permanent magnet eddy current coupling is established; by considering the skin effect, the analytical model of eddy current density is set; the analytical model of electromagnetic-transfer torque is given with the demagnetization effect taken into consideration. Based on the established analytical calculation model, the variation law of air-gap magnetic induction intensity, eddy current density distribution and magnetic torque characteristic curve are analyzed and plotted in detail. At the same time, finite element simulations of the air gap magnetic field, eddy current density and electromagnetic-transfer torque are carried out based on multi-physics, and the results are compared with analytical calculations. Moreover, the paper analyzed the thickness of magnet conductive plate impacts on eddy current and explored relations between torque and coupling distance under different pole pairs. Finally, in order to verify the simulations, the prototype test of torque transfer characteristics is carried out. This paper compares the experimental results with the theoretical analysis and simulation results, and finds out the error is within the allowable range.

The Experimental Study on "Soft Start" of Mine Permanent Magnet Coupling

The "soft start" problem was studied for magnetic coupling in coal mine by experimental method. At first, the starting condition of magnetic coupling was analysed. Aaccording to the load characteristics of conveyor. Secondly, the torque characteristic curve, speed characteristic curve and current starting curve were plotted using the experimental data. From three kinds of characteristic curve we have conclusion that the output torque and output speed is much less than the input torque and input speed, the starting current value with the load was less than the starting current value when directly connected. That means magnetic coupling with the soft start characteristic.

Study on powertrain system for CNG-electric hybrid city bus

In order to obtain better economy and power performances of compressed natural gas (CNG) and electric hybrid city bus, the powertrain system is designed and studied in this paper. Based on manufacturing technology, operation cost and dynamic property, economy is regarded as the main optimization goal for CNG-electric hybrid city bus, which determines the structure of powertrain system of CNG-electric hybrid city bus. Vehicle control strategy is established by working conditions. Some key component parameters are matched and designed. Work model of motor/generator is established, and torque characteristic curve of motor/generator is obtained. Full vehicle model of CNG-electric hybrid city bus is established by ADVISOR software. Comparison with tradition natural gas city bus, the maximum gradability rises by 69.8%, the maximum gradability of 20 km/h is 25.4%, the maximum speed rises by 8.6%, and the acceleration performance of 0∼50 km/h rises by 21.9%. The fuel consumption reduces by 23.3% in the BC-CTC cycle working condition, and the fuel consumption reduces by 25.1% in the ECE+EUDC cycle working condition. So, the performances of power and economy have been obviously improved, compared with traditional CNG city bus, which indicates that this method can be used to study the powertrain system of CNG-electric hybrid city bus.

Research on Torque Ratio Based on the Steering Wheel Torque Characteristic for Steer-by-Wire System

Steer-by-wire system can improve the performance of vehicle handling stability. Removing the mechanical linkages between the front wheels and the steering wheel leads to a key technique of force feedback for steer-by-wire system. In view of the characteristic of variable torque transmission ratio for steer-by-wire system, this paper proposes a method for designing torque ratio based on the steering wheel torque characteristic for steer-by-wire system. It converts the torque ratio design into equivalent assist torque design by analyzing their relationship. It achieves the torque ratio design at different conditions based on the negative equivalent assist torque characteristic curve. Simulations and vehicle experiments are conducted by the proposed method, and the results show that the design goal has been achieved and the steering wheel torque characteristic obtained is very similar to that of the reference car.

The Research for the Energy Saving Effect of Permanent Magnetic Drive Technology in Pumping Systems

The purpose of this article is to analyze the energy savings of drive technology for permanent magnet in pumping systems applications. Studied the system structure and working principle of permanent magnetic actuator, according to the production parameters of pumping system collected before and after installation, drew the superimposed slip torque characteristic curve for the motor, analyzed the movement of rod load and the crank shaft, and to study the changes for rod power and active power of pumping system. did data comparison and analysis, showed that the magnet actuator improves the dynamic performance of pumping system, decrease the fluctuations of load and torque and reduced installed power of drag motor, theoretical analysis matched experimental results, confirmed the drive technology for permanent magnet in pumping system applications have a good energy saving effect.

Comparison of Scalar and Vector Control Strategies of Induction Motors

Currently the use of three-phase induction machines is widespread in industrial applications due to several methods available to control the speed and torque of the motor. Many applications require that the same torque be available at all revolutions up to the nominal value. In this paper two control methods are compared: scalar control and vector control. Scalar control is a relatively simple method. The purpose of the technique is to control the magnitude of the chosen control quantities. At the induction motor the technique is used as Volts/Hertz constant control. Vector control is a more complex control technique, the evolution of which was inevitable, too, since scalar control cannot be applied for controlling systems with dynamic behaviour. The vector control technique works with vector quantities, controlling the desired values by using space phasors which contain all the three phase quantities in one phasor. It is also known as field-oriented control because in the course of implementation the identification of the field flux of the motor is required. This paper reports on the changing possibilities of the revolution – torque characteristic curve, and demonstrates the results of the two control methods with simulations. The simulations and the applied equivalent circuit parameters are based on real measurements done with no load, with direct current and with locked-rotor.

Analysis Model and Inherent Characteristics of Torsional Vibration of the Dual Mass Flywheel-circumferential Short Spring Introduced Friction

Friction is for the first time introduced into the analysis and calculation of the relation between torque and torsional angel of the dual-mass flywheel-circumferential short spring, and the mechanical model of torque characteristic curve basically agreeing with the test result is obtained. Based on the established dynamic model of the engine-dual mass flywheel torsional damper-transmission system, the influences of various parameters on the system inherent frequency is analyzed. The concept of using friction to increase torque and overload protection is introduced into the design of dual mass flywheel, thereby providing design ideas for the development of high-performance dual-mass flywheel products and revealing the good intrinsic nature of the vibration damper of dual-mass flywheel with friction introduced. It is concluded that the analysis model is more authentic and helpful to improving the damping performance of product by taking into account the characteristic of friction, also the resonance speed can be completely isolated beyond the working speed of engine by adjusting the stiffness k1 of the dual-mass flywheel, the moment of inertia J1 of the primary flywheel and the moment of inertia J2 of the secondary flywheel inertia. Increasing the parameter J1 while reducing the parameter J2 is helpful for avoiding the resonance.

Evaluation of apparent viscosity of liquid-containing porous particles by the intrusion method using a conical rotor

The apparent viscosity of a wet powder consisting of porous silica particles and a viscous liquid was evaluated by means of a newly developed powder rheometer in which a rotating conical rotor with grooves on the surface intrudes semi-statically into the powder bed. Using this rheometer, the relationship between the shear torque and the depth of intrusion, i.e., the torque characteristic curve, was measured under various conditions. The shear force acting on a contact point between the particles was estimated from the torque characteristic curve. Above the critical liquid amount in which the pores of the particles were filled with the liquid, the shear force increased with an increase in the thickness of the liquid film formed on the particle surface regardless of the pore volume. From the change of shear force with the physical properties of the liquid, it was clear that the shear force is closely related to the liquid bridge force acting on the contact points between the particles. The apparent viscosity coefficient of the wet powder was determined from the shear rate dependence of the shear force. At the relatively high liquid amounts corresponding to funicular and capillary states, the apparent viscosity coefficient increased sharply with the thickness of the liquid film since the viscosity of the liquid strongly affected the shear flow of the wet powder. Subtle changes of the apparent viscosity due to the liquid amount and the physical properties of the liquid can be sensitively detected by using the rotary-intrusion method.

Preliminary study on axial-type BSCCO superconducting motor

A small axial-type BSCCO high- T c superconducting motor cooled with liquid nitrogen has been fabricated and tested in terms of speed, torque and speed–torque characteristic curves. BSCCO bulky disk is used to be 120 mm in diameter and 8 mm thick, and two-pole concentrated armature winding is fed with the PWM inverter. The BSCCO machine could substantially operate as hysteresis motor. In the experimental motor, M– H characteristic curves at different local points of the BSCCO disk were not same, air-gap magnetic flux density was not completely sinusoidal, and viscosity losses existed due to liquid nitrogen, so that the motor could not rotate at synchronous speed. Performances have been evaluated and an equivalent circuit of the BSCCO-2223 bulk motor has been estimated from test results.