Mathematical Models Of Torque Research Articles

Investigation of design methodology for doubly-fed bearingless flux reversal motor

This article integrates the technology of bearingless motors with the basic theory of magnetic flux reverse motors, proposes a doubly fed bearingless magnetic flux reverse motor, and conducts research on its structural design, operating mechanism, electromagnetic performance analysis, mathematical model, control method, digital control system, and other aspects. The basic structure of a new type of doubly fed bearingless magnetic flux reverse motor is designed, and the principle of radial suspension force generation is studied. The performance related to torque and radial suspension force is analyzed. A mathematical model of torque and radial suspension force is established, including magnetic field distribution, no-load permanent magnet flux, and no-load back electromotive force. A doubly fed bearingless magnetic flux reverse motor system is designed and constructed, and inductance experiments are conducted.

Control Method of Redundant Winding BLDC for Deep Lunar Soil Drilling

The deep lunar soil loading process is complicated and volatile; it is difficult to achieve stable and reliable drilling sampling. In order to realize the rotary drive control of low-speed high torque start-up and high-speed cutting dumping of the spiral drilling tool, the redundant double backup winding BLDC motor is used as the driving source of the spiral drilling tool, the mathematical model of torque and speed of the double winding BLDC motor is established, and a dual winding BLDC motor is designed. The drive circuit topology scheme of synchronous operation of winding is simulated and analyzed, and the control performance experiment is carried out combined with the prototype. The test results show that the topological structure of the driving circuit can meet the driving control requirements of lunar soil and lunar rock drilling sampling process, and improve the safety and reliability of the drilling sampling process.

Characteristic Analysis of a New Double Stator Bearingless Switched Reluctance Motor

In order to improve the performance of bearingless switched reluctance motor (BSRM), this paper proposes a new double stator bearingless switched reluctance motors (DSBSRM). The new DSBSRM adopts an inner and outer double stator structure, the inner and outer stators are separated by magnetic isolation frame to solve the coupling problem between torque control and suspending force control. In suspending control system, the new DSBSRM adopts the working mode of hybrid excitation, permanent magnets are used to provide a bias magnetic field, electromagnetic is used to adjust the magnitude of hybrid magnetic field, thus it has larger suspending force under the same current. Further, the torque mathematical model and the suspending force mathematical model are established, and the difference caused by rotor eccentricity in air gap reluctance and in magnetic flux leakage are considered for more accurateness in the suspending force mathematical model. The 2D simulation model of the new DSBSRM is established by using finite element simulation software, and the mathematical models of torque and suspending force are verified, then the magnetic field characteristics of the new DSBSRM is analyzed, the important parameters influence of the magnetic field characteristics is analyzed. Finally, the new DSBSRM is compared with the 16-phase BSRM, the simulation results show that the torque output of the new DSBSRM is about 100% larger than that of the 16-phase BSRM, the increase percentage of suspending force varies with the change of current, but the output of suspending force is always larger than that of the 16-phase BSRM. Therefore, with the improvement of output performance, it can better cope with various workplaces.

Design and Analysis of a Novel Bearingless Segmented Switched Reluctance Motor

A novel bearingless segmented switched reluctance motor (BSSRM) is proposed in this paper to solve the coupling problem of the traditional bearingless switched reluctance motor (BSRM). Different from traditional BSRMs, the proposed BSSRM adopts the double stator and segmented rotor structure, thereby making the motor operate in short flux paths and the magnetic flux path isolated between torque and suspension system. On the basis of introducing the structure and working principle of the BSSRM, the mathematical model of torque and suspension force is deduced. The 2D finite element simulation model is established by the Ansoft software. The influence of structural parameters on torque and suspension system is analyzed, and its electromagnetic characteristic and decoupling characteristic are analyzed. Compared with the double stator bearingless switched reluctance motor (DSBSRM), the BSSRM not only improves the torque and suspension output but also weakens the coupling between torque and suspension system. Finally, the simulation results verify the effectiveness of the BSSRM.

Optimization Design of Bearingless Synchronous Reluctance Motor

In order to overcome common drawbacks of the low torque density and power factor for conventional bearingless synchronous reluctance motors (BSynRMs), a novel BSynRM rotor structure with ferrite magnets is designed in this paper. First, the basic structure and operation principle of the BSynRM are introduced, and the mathematical models of torque and suspension forces are deduced. Second, based on the finite element analysis method, the parameters of flux barriers layer, rotor rib width, and permanent magnets are optimized to increase the salient pole ratio and the difference between d and q axes inductance. Third, the performance of torque, suspension forces, and power factor for the optimized motor is compared with that of the traditional BSynRM. The research results show that the torque density and power factor increase about 54.4% and 56.3% respectively at optimal angle, whereas the average suspension force decreases about 15.7% owing to magnetic saturation. The optimized motor is validated to have good suspension and speed regulation performance.

Analysis of Winding Forms for Bearingless Flux-Switching PM Motor with U-core Stator Laminations

Due to low-cost and magnet-free rotor structure, bearingless flux-switching permanent magnet motors (BFSPMs) are more applicable to high-temperature and/or disposable applications. A BFSPM with U-core stator laminations is investigated in this paper. First, the operational principle is analyzed in accordance with the influence of winding connection manners on torque and radial forces, and then the basic winding arrangement for torque windings and radial force windings is determined. The mathematical models of torque and radial forces are derived based on the basic winding arrangement. Followed by that, a method to select winding terminal connection manners is proposed by taking into account control scheme and power inverter topologies. A promising terminal connection is found from three possible candidates and a detailed current model for torque and radial force control are given for the promising winding forms. Finally, relevant electromagnetic properties of the motor are verified and analyzed by finite element analysis.

Experimental comparison between reaction wheel attitude controller strategies

Systems for satellite attitude control are usually designed based on modern control techniques, which assume that the plant, sensors and actuators have linear behavior. A reaction wheel is an actuator that produces a torque as a function of electric current applied to a brushless DC motor. Ideally the output torque should be proportional to the current, but Coulomb and static frictions in the bearing introduce non linearities in the output torque, as function of the angular velocity of the wheel, especially at low speeds, near zero. These non linearities become more relevant specially in reaction wheels that are designed to rotate in both directions, causing the controller error to increase significantly at sense of speed reversals (zero crossings). This article presents results of a control orientation of an air bearing table by means of a reaction wheel. To check the controller action during a zero crossing, a small fan was attached to the table, producing a torque whose magnitude can be altered by adjusting the direction of the airflow. The control loop uses a fiber optic gyroscope (FOG) as angular velocity sensor. A PID digital controller drives the wheel based on the angular position of the table with respect to a given reference. In order to have a controller with a linear output torque, a mathematical model of torque was developed as function of the input current and wheel speed, from which it was constructed an algorithm of the inverse function, so that the non linearities were partially compensated (dynamic compensation). The results indicated that dynamic compensation can effectively reduce the maximum pointing error during zero crossing, while keeping constant other parameters such as response and settlement time.