Huang Shoudao

A study of the control strategy on rotor field orientation for brushless doubly-fed machine

The brushless doubly-fed machine (BDFM) has gained renewed attention in variable-speed drive applications in recent years for its features of simple structure, favorable characteristics and economical operation. In this paper, the implementation of a field orientation control strategy of a BDFM for adjustable speed drives is presented. With the help of a synchronous reference frame dq model, a rotor flux orientation scheme is employed to achieve decoupled control of torque. A 30 kw BDFM prototype system with 80196KC single ship based controller and bidirectional power converter is built to verify the theoretical analysis. Computer simulation and laboratory experimental results are shown in favorable agreement.

Fuzzy-based power factor control for brushless doubly-fed machines

Other work has illustrated the potential benefits of brushless doubly-fed machines (BDFMs) in adjustable speed drive applications. But its dynamic performance is far from being satisfactory. The paper proposes a fuzzy control strategy for the power factor based on the model of BDFMs in the dq0 frame. Simulation shows that a BDFMs power factor can be controlled efficiently by adjusting the voltage or current amplitude of its control winding with the fuzzy controller.

Direct torque control for PMSM based on model reference adaptive system

The direct torque control based on two PI regulator of the torque and flux and the two decoupling components of motor space voltage vector, torque and flux, was used in surface mounted permanent magnet synchronous motor. While the stator flux estimation method based on rotor position and stator current was applied. Besides, the speed identification based on model reference adaptive system (MRAS) with the flux model as an adjustable model replaced the speed sensor to estimate the rotor position. All of aboved constitute the space voltage vector direct torque control system of permanent magnet synchronous motor on the base of model reference adaptive system. Simulation and experiments demonstrate that the proposed method can estimate the stator flux and speed reliablly and validly. And the dynamic and stable characters of the whole control system is very good.

Research of interior permanent magnet brushless DC motor for electric vehicles

Permanent magnet brushless motors for electric vehicles are presently given an increasing attention. With this trend, this paper deals with an interior permanent magnet (IPM) brushless DC motor (BLDCM), which is supposed to apply in a two-seater pure electric car. Firstly, the performance indicators of the motor were determined according to the power requirements of the car at different driving speed, and a 10kW IPM-BLDCM was designed preliminarily. Then, choosing air gap length, permanent magnet thickness and the number of stator winding turns as variables, parametric analysis was made to research the influence of structural parameters on system efficiency and the torque-current ratio. After an optimization design, a prototype was fabricated and tested. The test results show that the optimized prototype can meet the need of the driving system both in constant torque region and constant power region.

Research on grid synchronization of grid-side converter in direct drive wind power generation system

In grid-side converter control in direct drive wind power generation system, grid voltage oriented vector control strategy is used. The fast and precise detection of the amplitude and phase of the fundamental frequency voltage components is a crucial issue in the design of grid synchronization of grid-side converter. Because the dynamic performance of the phase-locked loop based on the single synchronous reference frame PLL is dissatisfactory when the grid voltage is unbalanced and distorted, the paper proposes an enhanced PLL system combining positive sequence computation unit and phase-locked method. Using this method can realize fast and precise detection of the amplitude and phase of the fundamental frequency voltage positive sequence component in the presence of voltage unbalance and distortion. Simulation results verify the effectiveness of the proposed scheme.

Study of neural network application on direct torque control of induction machine

This paper presented a BP neural network resistance estimation scheme for direct torque control (DTC) of an induction machine. The neural estimator observes the stator current to detect the changes in the stator resistance. Simulation models are constructed using MATLAB/SIMULINK to analyse the application of the neural network on the DTC, which is trained to follow the relationship between the stator current and stator resistance. Improved performance such as dynamics characteristic can be tested through the simulation.

Design and research on variable-frequency speed-regulating electric power dynamometer motor

This paper covers the design of variable-frequency speed-regulating (VFSR) electric power dynamometer system which is a new topic in 1980s. It discusses the effect of a variable frequency power supply on a dynamometer motor (DM), which is one of the key components of the dynamometer system, and supplied by a variable frequency power source. Also, the design characters of this kind of motor are introduced, and a CY250-4 110 kW DM is designed based on CAD. Finally, the validity and correctness of the design program are testified to by the test data.

Characteristic analysis of the cryogenic permanent magnet synchronous motor for the submerged LNG pump

This paper introduces a submerged LNG (liquefied natural gas) pump cryogenic permanent magnet synchronous motor (PMSM). A 22kW/6000rpm prototype is designed for low temperature operation at −161°C. The influence of temperature on magnetic and electric parameters of materials is analyzed, and a coupled simulation model of electromagnetic-fluid-thermal-stress field is established. On this basis, the motor characteristics such as the loss, back EMF and torque are obtained. The accuracy of the simulation model is verified by the prototype test at −196°C liquid nitrogen. Simulation and test results show that the performance of the cryogenic PMSM is better than that of the traditional motor.

Research on energy management for the swing system of hybrid excavator

The traditional hydraulic excavator has some questions, so as energy waste, Environmental pollution. In this paper, The control strategy of Oil-electric hybrid excavator presented swing mechanism brake energy recovery system is investigated. Permanent magnet synchronous motor feedback system moving process was analyzed. The control strategy is verified, the results show that the scheme can effectively recover braking energy excavator and high energy conversion efficiency.

Research on optimal design of permanent magnet synchronous motors based on field-circuit coupled method

This paper deals with the optimal design of permanent magnet synchronous motors (PMSMs). Firstly, the general rules and principles of motor optimization are summarized, and a field-circuit coupled optimal design method is presented based on combined selection of variable parameters, objective functions and constraint conditions. Then, choosing multiple structural dimensions as variables, parametric analysis is made to research the influence of structural design parameters on performance of the PMSM. On this basis, an optimal design for a two-pole line-start PMSM is made, which can successfully reduce the dosage of permanent magnet and improve the performance-price ratio.