Jinqi Ren

Loss model establishment and efficiency optimization control of single sided linear induction motor

Single sided linear induction motor (SLIM) has good direct drive ability though its efficiency is poor compared with the rotary counterpart. The motor model including iron loss under synchronous coordination is established and the variable loss function is derived in the paper. In the proposed equivalent circuit model of SLIM, to consider the influence of primary leakage inductance on loss calculation, the iron loss resistance is paralleled with primary magnetizing branch instead of mutual magnetizing branch. The efficiency optimized control (EOC) algorithm based upon the motor loss model is presented. The operation efficiency of motor is improved by using the EOC scheme and the pulsation of magnetization and thrust is not significant. The loss model is validated via calculation comparison, and the experimental results show that the control scheme presented in the paper can improve the motor efficiency when the SLIM is working under light load condition, and the EOC scheme does not deteriorate the dynamic behavior of motor operation.

A novel dead time compensation method of single-phase PWM rectifier

Because Single-phase PWM rectifier usually runs unity power factor condition; the phase between grids input voltage and current are the same. In this paper, a novel dead time compensation method of single-phase PWM rectifier is proposed by the observation of grid input voltage based on resonant controller phase-looked loop. The new method avoids the noise of the current detection, so that zero-crossing detection is more accurate, and does not cause the phase delay. Comparative analysis with traditional dead time compensation method based on the current. The simulation and experiment results show that the grid input current total harmonic distortion with grid input voltage observation are lower and compensation effect is better.

Implementation of full order flux observer in direct field orientation control of high power traction

In high power traction system, direct rotor field oriented control (DFOC) is widely used due to its high dynamic response and robustness in the estimation of the motors rotor flux. The close loop full order flux observer is a good combination of traditional current model and voltage model flux estimators and suited for wide speed range application with no necessary of transition between the two types of estimators. The selection of observers gain is one determining factor of the property of the observer. In this paper, a new gain design method is proposed and validated by simulations.

Close-loop induction motor rotor flux field-oriented control in single wave voltage feeding

Voltage-source converter (VSC) is has been applied widely in feeding the induction motor(IM). In high power wide speed-range AC drive, such as High Speed Railway Train traction converters, the IM usually are fed by Single Wave (SW) voltage in high speed reign, due to the switching loss and making full use of the voltage that DC link can provide. The amplitude of stator voltage vector is restricted constant in the mode, which brings new problems to the conventional field oriented control (FOC) for IM. This paper discusses the strategy for IM Rotor Flux FOC under single wave voltage feed. The proposed scheme provides quick torque response in the single wave mode under direct rotor FOC. Simulation and experimental results are shown to validate the effectiveness of the control.

Analysis and spectral characteristics of a PWM rectifier with frequency jitter and random pulse width modulation techniques

The acoustic noise spectrum in power electronic system is closely related to the spectrum of the voltage waveform and can be reduced by avoiding the concentration of harmonic energy in distinct tones. Frequency jitter and randomized pulse width modulation are two methods to reduce mechanical vibration and acoustic noise in power electronic. These two techniques can make the harmonic spectrum of inverter output voltage be continuously distributed without affecting the fundamental frequency component. In this paper, Frequency jitter and randomized PWM rectifier and its practical design procedure are presented.

Performance study for linear induction motor considering winding function method and control scheme

This paper adopts winding function method in linear induction motor performance study and presents a new equivalent circuit. It can predict stable and transient performances considering end effects, half filled slots, saturated iron and skin effect. Furthermore, the model is able to analyze different working states considering various control schemes, such as scalar control, vector control, direct torque control and etc.The results indicate that winding function method is rational to describe motor performance connecting with control schemes, which is useful to motor design and control prediction.