Advanced Materials Research Vols. 588-589

Abstract: Permanent Magnet linear synchronous motor (PMLSM) exist the problem of normal force fluctuation, especially in the servo feeding system of high-precision CNC machine tools. The normal force fluctuation can cause the feeding table in vibration and produce resonance with other moving components of the servo feeding system. It is produced by normal electromagnetic force wave acting on iron cores of PMLSM. In this paper, the analytical expression of normal electromagnetic force wave of single-side PMLSM is deduced with the method of MMF (magnetomotive force) magnetic permeance. And based on this, analyze composition and classification of the force wave component; the further study of the influences to the force wave order and amplitude when the coefficients of the electric machine are changed is done. Then, base on a PMLSM with 6 poles and 36 slots, the results of analytic calculation are accordant with the FEM simulation ones. These results prove the analytical expression is correct and accurate.

Abstract: Due to ventilation structure of high power high-speed permanent magnet motor is complex and rotor cooling is difficult, the rotor cooling system was designed for a 1020kw 19000r/min high-speed permanent magnet motor and fluid field calculation model was established through the fluid flow CFD simulation software, and then the solving regional and boundary conditions of the 3D fluid field was determined. The numerical calculation and analysis was carried out and 3D fluid field distribution was get within the ventilation system. On the basis of the results of the flow field calculation, the coefficient of wall heat can be got more accurately, which provides a basis for the optimization and count of the MW-level high-speed motor temperature field.

Abstract: Brushless electric excitation synchronous machine is a new kind of AC machine. There are two sets of windings with different pole numbers on the stator. It eliminates the brushes and slip rings. The air gap magnetic density of brushless electric excitation synchronous machine is achieved based on Ansoft. And the influence of stator windings with different pole numbers on coupling capability is analyzed. All the results are investigated to provide the guide for the optimal design.

Abstract: For the problem of heavy load starting induction motors in operation efficiency and power factor are low, a kind of heavy load starting light load running induction motor with high-performance is presented. In order to study the feasibility of this motor, the state equation of the motor is established and the dynamic simulation program of the motor is compiled. Finally, the program is simulated using software and the simulation result is analyzed.

Abstract: The claw pole machine with outer permanent magnet rotor (CPMPM) is a special kind of the claw pole machine. The trapezoidal current drive as a new drive in this motor is a new attempt. On the basis of analyzing its structure, material, characteristics and operating mechanism have proposed a new conduction manner of the trapezoidal current drive；For this machine is not easy to place position sensor, a new function of rotor position-based approach has been put forward to estimate the rotor position in this paper. It has been show that this method can accurately and quickly estimate the rotor position by simulation .It has been prove that this method has good dynamic and static performance.

Abstract: The paper mainly introduces the idea of the design, system composition, and working principle of ‘Marine electrical propulsion simulator’. A fast start experiment is designed to obtain the data and curves from the small-scale simulator. A conclusion is drawn from the experiment that it is dangerous to set the propulsion motor at a high speed during the start period.

Abstract: Because of the structure of oilfield distribution network and the demand of oilfield digital management, this paper designs a scheme which can realize parallel transmission of multichannel upstream signals according to orthogonal coding. The weak interaction between signals is proved through the platform. Meanwhile, we test in the same 6kV line of oilfield power network scene, and realize parallel transmission of 6 upstream signals. Thus, it creates favorable conditions for the transmission of greater capacity of oil monitoring information through the power frequency communication technology.

Abstract: Power flow solution is one of the most important means of power system stability analysis. While parsing algorithm is the basis of power flow analysis. The idea of iteration is frequently used in power flow solution because of the characteristics of power system itself. Textbooks, however, use the gradual iterative thought without rigorous demonstration of the conditions for convergence. From the point of view of mathematical analysis, the article not only gives a proper way to determine the convergence or divergence of the power flow but also provide the exact solution of a simple power flow with an example to demonstrate the validity of the algorithm.

Abstract: The paper analyzed the composition of the aircraft synchronous generator system. The simulation model of the three-stage synchronous generator is established in the environmental of MATALB according to the motion equation of generator and coordinate transformation. Proposed a control algorithm based on the Sliding-mode Variable Structure Control (SVSC) theory after analyzed the conventional control algorithm of voltage regulator. Particularized the realized method of the SVSC algorithm is proposed. Simulation of both control algorithms were conducted under MATLAB. Simulation results indicated the validity of the SVSC algorithm and advantages against conventional control algorithm.

Abstract: This paper illustrates a novel electronic current transformer (ECT) with a power source at ground potential. Employ the insulation structure of the traditional transformer insulated by SF6, the sensing unit with an air-core coil for measurement and protection transmits the electrical signal to the signal processing unit at the ground potential. Then the optical power source could be abandoned and the reliability is effectively enhanced. Utilizing mathematical models, designations and emulations have been done to compute the influence of the ambient temperature. Tests have been done and the experimental results show that this ECT meets the requirement of the 0.2s class for measurement and 5PTE for protection in IEC60044-8 respectively.