Hu Sun

Sensorless Control of Permanent Magnet Synchronous Motor with Stator Flux Estimation

As the mechanical sensor of PMSM easily break out, attentions are paid to the PMSM sensorless control method. In this paper, a modified stator flux methods based on the active flux is proposed, which can estimate the rotor position and speed of the motor after accurate stator flux estimation using active flux. This method is of simple calculation and less dependence on motor parameters, and it suits for both SPMSM and IPMSM. The simulation results and experimental results show the method can estimate both the rotor position and speed in either abrupt load torque or variable speed condition.

Characteristics of Linear Induction Motor Considering Material of Reaction Plate Change

In this paper, a method of calculating the parameters of equivalent circuit model of linear induction motor(LIM) is proposed based on numerical analysis and finite element method(FEM). The method is proved accurately through the traditional removed and locked tests. Material change of reaction plate’s effect on how equivalent circuit’s parameters change and the influence on thrust and vertical force are analyzed through this method. The co-simulation of Maxwell and SIMULINK is analyzed. A control algorithm to compensate the effect of material change is presented. The compensation is based on equivalent circuit parameters variation and indirect vector control. Simulation results have shown the algorithm had good performances.

Analysis of electrical characteristics of the four-quadrant converter in high speed train considering pantograph-catenary arcing

Pantograph–catenary disconnection occurs quite frequently in high-speed situations. Pantograph arcing has a significant impact on the contact surfaces and power quality. This article focuses on the effect on the electrical characteristics of the four-quadrant converter of pantograph arcing. An arc model which combines Cassie’s arc model with Mayr’s arc model is built. This article mainly researches the influence of the pantograph arcing on the four-quadrant converter in different durations. Pantograph arcing leads to voltage pulse in voltage, as well as the harmonics in the current of the alternating current side. At the same time, the direct current voltage decreases when the arc occurs. Therefore, it can ultimately decrease the output torque and increase the torque pulsation of the motor.

Medium-frequency oscillation analysis in high-speed railway system considering power supply system with LCL model

Single-phase four quadrant converter is an important part of high-speed train traction drive system. High-speed train and power supply system coupling form the high-speed rail system. Focusing on the medium-frequency oscillation phenomenon between the AC power supply system and high-speed trains, this paper considers digital control delay effects in 4Q converter modeling and analysis. It presents a mathematical model for a single-phase 4Q converter, coupling with the power supply system impedance, and it uses Hopf bifurcation theory of nonlinear systems, small disturbance method and the root-locus method to study on AC power railway system stability, especially on the system stability with different circuit parameters and control parameters. The numerical simulation results and the experiments on the small scale prototype hardware platform have verified the theoretical analysis.

A novel flux-weakening control strategy for permanent magnet synchronous motor

Flux-weakening control of permanent magnet synchronous motor (PMSM) based on single current regulator has high dynamic performance. But the fixed given q-axis voltage decreases the motor’s efficiency and load capability. This paper presents a new control strategy with variable q-axis voltage, which can adjust q-axis voltage fully using the motor DC voltage to make motor working at the optimal operating points. It makes the motor efficiency and improves load capability. This method is easy to achieve and does not depend on motor parameters. The results of simulation verify the method in this paper.

Torque and flux control for induction motor with L/sub 2/ disturbance attenuation

A robust torque and flux control strategy for induction motor is proposed with L/sub 2/ disturbance attenuation. The L/sub 2/ gain from the disturbance to the penalty signal denotes the robustness of the control system to some extent. The appropriate control method can reduce the L/sub 2/ gain to a given level. The controller design proceeds along two stages. The first stage is to choose the desired flux and current state, which match the control objective. In the second step, the tracking error system is considered and the control law is designed to force the L/sub 2/ gain in a given region. The robustness is verified by simulation results with uncertain rotor and stator resistance.