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Permanent magnet motors are coming more and more popular in wind generation applications. In the high efficient wind power generation system, the accurate information about rotor position is very important. MRAS schemes offer simpler implementation and require less computational effort. Because the voltage model involves pure integrator in the classical model reference adaptive system (MRAS). This...
This paper deals with coupled electromagnetic-thermal-fluid analysis for temperature prediction of a power transformer. Electric power losses are calculated from finite element method (FEM), and are used as input source of thermal-fluid analysis based on computational fluid dynamics (CFD). In order to accurately investigate the temperature distribution in a power transformer, the thermal problem should...
The structure and the working principle of Magnetically Controlled Saturated Reactor (MCSR) were expounded, the 2-D finite element model of the 500kV DC help magnetic type of MCSR was established, the capability of single-phase MCSR was 40MW. The magnetic field distribution in the core was analyzed, currents in the working windings of the MCSR were calculated, the control characteristic curve was...
An ultra high voltage auto-transformer has been analyzed in this paper. The maximum voltage of this auto-transformer is 750 kilo voltage, and the capacity is 500 millions volt-ampere. This paper primary introduced the calculation and analysis for the main insulating structure of single-phase power auto-transformer. The whole electric field of transformer be calculated by the finite element analysis...
A contactless inductive energy transmission system (CIETS) transmits electric energy via a alternating magnetic field through an air-gap. In contrast to a non air-gap energy transmission system, the power capacities per frequency of the primary and secondary sides in a CIETS are different. Therefore, a new method is needed for designing a CIETS that has an asymmetric structure. In this paper, we propose...
An 18-pulse rectifier based on a step-up or step-down autotransformer in star-fork connection is presented. The voltage vector diagram of the autotransformer is given out and the connection of windings is also analyzed. By arrangement the secondly windings properly, the output voltage can be set in a wide range below or above the 3-phase uncontrolled rectifier with a low THD in the input current....
If grid-connection impact current is very large, the power grid and dual PWM converters will be damaged. It is necessary to analyze the grid-connection transient current. In this paper based on stator rotor differential equations under the two-phase rotating coordinate system, the grid-connection transient transition process as well as the principle of impact current generation was analyzed in detail,...
This paper proposes a direct power control (DPC) strategy for cascaded brushless doubly fed induction generator (CBDFIG), which eliminates the slip rings and brushes in conventional DFIG wind turbine systems and features quick dynamic response and excellent steady state performance. Prior methods for controlling CBDFIG are based on vector control (VC), which is complicated and requires much tuning...
Switched Reluctance Motors (SRMs) show great advantages of structural simplicity and high reliability in aerial starter/generator applications. This paper introduces the implementation of a high speed switched reluctance starter/generator system. First, the paper proposes a modeling method for switched reluctance starter/generator system, including switched reluctance machine and power circuit. The...
This paper focuses on the harmonic suppression function of the damper windings for air-gap magnetic field of line-start permanent magnet synchronous motors(LSPMSM) using finite element analysis (FEA). The Squirrel-cage bars damping function of LSPMSM not only reduces effectively the air-gap density harmonic components, but also enhances the starting performance of LSPMSM. The harmonic components of...
Aiming at realizing the performance of high torque, low speed and high reliability for the Permanent Magnet Synchronous Machine (PMSM), a superpower multi-unit PMSM was designed, which had five units and each unit including an independent three-phase star-connection windings and an independent driver device. When the multi-unit PMSM was running under normal conditions, its operation was very similar...
A transformerless converter which is suitable for multiphase drive system application is presented in this paper. This topology employs a cascaded H-bridge rectifier as the interface between the grid and multi inverters which drive the multiphase motor. Compared to the conventional structure, the new topology eliminates the input transformer and also has the advantages of using this topology are four...
Based on the analysis of the two existing typical linear motors for Stirling Cryocoolers, a novel structure linear motor is developed, which adopts assembled stator core and has the characteristics of high air gap flux density, small volume, light weight and simple installation. Firstly, the size estimation formula is established in this paper, and then the motor parameters are optimized with the...
In order to improve the coupling capability and operating performance of brushless doubly fed machine(BDFM), a novel hybrid rotor structure is designed in this paper, finite element analysis(FEA) indicates that this type of rotor has higher magnetic field coupling capability, more excellent no-load characteristic and better torque capability in comparison to traditional rotor structure. The conclusions...
The voltage variations are inevitable in most kind of dc sources used in multilevel inverters. Therefore, using the selective harmonics elimination (SHE) techniques to eliminate low order harmonics considering specific combination of constant voltage sources seem to be impractical or less usage. In this paper, by employment of fuzzy logic controller, a suitable control method for elimination the low...
The single-phase induction motor which used in household appliances has problems such as low efficiency and poor power factor. In order to solve issues, this paper proposes a three-phase variable frequency PMSM in household appliances which is supplied with the single-phase power. By comparing the performance of the three-phase variable frequency PMSM with the single-phase induction motor through...
This paper presents a predictive control scheme of DC-link voltage for back-to-back converters based on energy balance modeling. Since the variation of DC-link voltage is affected by the energy mismatch between rectifier and inverter, the energy distribution in a rectifier-inverter is analyzed. Moreover, in order to calculate the input and output energy in one control period accurately, the grid current...
The paper presents a digital servo system of the permanent magnet synchronous motor (PMSM) implemented in the satellite antenna position control. The novel control system based on DSP and CPLD modules is proposed to satisfy the requirements of the high performance servo system. The hardware and software control procedures are designed and developed. The objective of the whole digital system is to...
In this paper an indirect stator-quantities control (ISC) strategy for Brushless doubly-fed induction machine (BDFIM) is presented. The algorithm of calculating phase increment of control winding(CW) flux space vector in a sample period is obtained. The proposed ISC strategy is developed at the static two-axis model and can be used to control both the electromagnetic torque and CW flux in static reference...
Equivalent circuit model of induction motors was established and the formulas of power losses were given. Motor efficiency was optimized by Genetic Algorithm(GA) and Hybrid Genetic Algorithm(HGA). Power factor, breakdown torque ratio, locked-rotor torque ratio and locked-rotor current ratio were regarded as constraints and the optimal result is satisfying. Genetic Algorithm and Pattern Search Algorithm...
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