Advanced Materials Research Vols. 516-517

Abstract: For Brushless Doubly-fed Machine(BDFM), the main feature of field is that there are two kinds of magnetic fields differing in pole number in the machine’s iron circuit and the two fields have the same order of magnitude. Hence, it is difficult to calculate the machine’s performance accurately using conventional analytic method. In this paper, the author constructed one finite-element model of BDFM, and analyzed the machine’s performance using transient solver. The author also compared the finite-element method with experiment and conventional analytic method. Because taking into account the saturation, the results of finite-element method are closer to the measurements than that of conventional analytic method. The validity of model is verified.

Abstract: Heavy handling robot can transport goods automatically from the origin to the destination along the guide wire. During the operating process, light sensors are firstly employed to detect the robot’s relative position of guide wire, the test data can be brought in microprocessor S3C44B0X to be saved, analyzed, and processed, and then, according to the results of the information processing and the pre-set control algorithm, the system gives off the corresponding instruction and guides the robot along a pre-drawn line running smoothly to achieve the purpose of carrying the goods automatically. Heavy handling robot can be widely applied as an intelligent vehicle to workshop, factory, dock and other places.

Abstract: A dual-frequency microstrip patch antenna is proposed based on rectangular microstrip patch, with appropriating feed location selection of 50Ω coaxial line, two frequency are respectively applied to 0.8GHz and 0.9GHz. Size of antenna is designed based on the simulation software of HFSS from ANSOFT company, reducing antenna return loss by adjusting size and completing matching between patch and coaxial line, results are analyzed. Simulation results show the design and implementation of microstrip patch antenna have certain reference value with small return loss on 0.8GHz and 0.9GHz.

Abstract: This article developped a Calibration PC software for Motorcycle Electronically Controlled Engine System based on LabVIEW ,This software can accurately control the calibration parameters of engine working process,including injection pulse width and ignition timing.It is flexible, intuitive and convenient to motorcycle electronic control system’s calibration processing with the software of host computer monitoring by using LabVIEW.

Abstract: Brushless Doubly-fed Machine (BDFM) is a new type of the induction machine, which has wide application in the fields of variable-speed generator and drive systems. The key factor affecting its performance is the rotor structure. In this paper, taking wound-rotor BDFM for instance, firstly, according to the relationship between the equivalent circuit parameters of the BDFM, the core equivalent circuit model of the BDFM has been derived. Secondly, based on the core equivalent circuit model and the constraints of electromagnetic load, the power distribution between the power and control windings and the constraint condition of maximum output of active power has been obtained. Thirdly, according to the simplified model of the equivalent circuit, the copper loss and the relationship between the output power and efficiency of the machine have been investigated. Finally, the anlysis results are verified by the experimental data.

Abstract: The paper attempts to present some effective methods to reduce cogging torque for low-speed and direct-drive(LSDD) permanent magnet motor.

Abstract: As a new generator cooling technology, the evaporative cooling technology has the advantages of high-security, energy-saving and high efficiency. To solve the more serious problem of the large quantity of heat generated by stator collecting ring in huge hydro-generator, a new cooling system, the self-circulation inner evaporative cooling system of stator collecting ring, was proposed in this paper. To analyze and discuss the feasibility and operation characteristics of this new cooling system, an experiment platform of self-circulation evaporative cooling system of stator collecting ring was established with extremely asymmetric parallel flow branches. The experimental results show that under different heat loss work conditions, the experimental cooling system can operate normally. Under the rated work condition, the system can meet the cooling demands of actual generator and the wall temperature distribution of stator collecting rings is comparatively even. The feasibility of this new cooling system is confirmed. The conclusions in this paper provide the basis for the further research of this new cooling system.

Abstract: The forced circulation evaporative cooling system of stator in turbo-generator is a new cooling system under study, with the advantages of high-security, high efficiency and energy-saving. In this paper, an experiment table of this new cooling system with single hollow conductor was established. The flow characteristics of coolant in hollow conductor were analyzed and discussed by theoretical simulating and experimental researching. The results show that with the volume flow of coolant increasing, the variation tendencies of total flow resistance in hollow conductor and Xe are not monotonic and the prediction precision of total flow resistance in hollow conductor is satisfying with maximum relative error less than 10%. The length of subcooled flow boiling region in hollow conductor is relative long and can not be ignored. The conclusions in this paper can provide the theoretical and experimental basis for the further study of this new cooling system.

Abstract: The self-circulation inner evaporative cooling system of stator collector ring is a new cooling system for stator collector ring in hydro-generator, with the advantages of high-security, energy-saving and high efficiency. In this paper, the temperature distribution of stator collector rings in the new cooling system under different work conditions, were analyzed theoretically by simulating. The chosen correlations of flow resistance and heat transfer were introduced. Comparing with the experimental data, the simulation results show that the prediction precision of the temperature distribution of stator collector ring is satisfying with maximum relative error less than 9.13%. The simulation method in this paper is reliable and can be utilized in the applied engineering field.

Abstract: The mathematic model that based on decoupling vector space for six-phase permanent magnet synchronous motor (PMSM) is established. The six-phase PMSM is designed with two sets of Y-connected windings phase shifted by 30 electrical degrees. In the model, the variables of the motor are mapped to the α-β subspace associated with the electromechanical energy conversion and z1-z2 o1-o2 subspace that has nothing to do with the energy conversion subspace in the model. The model implies that different current harmonics have different effects on electromechanical energy conversion. The vector control scheme for six-phase PMSM is presented, in which the currents in the subspace α-β and z1-z2 are controlled in closed loop. A space vector pulse width modulation (SVPWM) algorithm of six-phase voltage-source inverter based on adjacent four largest voltage vectors is discussed. The voltage in α-β and z1-z2 can be modulated simultaneously. Through the simulation and experiment analysis, the vector control method and PWM technique for six-phase PMSM are proved to be feasible and effective.