Bingnan Li

Second-Order Sliding-Mode Observer With Online Parameter Identification for Sensorless Induction Motor Drives

Parameter identification plays an important role in speed estimation schemes. This paper presents a speed estimation scheme based on second-order sliding-mode supertwisting algorithm (STA) and model reference adaptive system (MRAS) estimation theory, in which both variations of stator resistance and rotor resistance are deliberately treated. A stator current observer is designed based on the STA, which is utilized to take the place of the reference voltage model of the standard MRAS algorithm. The observer is insensitive to the variation of rotor resistance and perturbation when the states arrive at the sliding mode. Derivatives of rotor flux are obtained and designed as the state of MRAS, thus eliminating the integration. Furthermore, in order to improve the near-zero speed operation, a parallel adaptive identification of stator resistance is designed relying on derivatives of rotor flux and stator current. Compared with the first-order sliding-mode speed estimator, the proposed scheme makes full use of the auxiliary sliding-mode surface, thus alleviating the chattering behavior without increasing the complexity. The robustness and effectiveness of the proposed scheme have been validated experimentally.

Analysis and Control of Multiphase Permanent-Magnet Bearingless Motor With a Single Set of Half-Coiled Winding

In this paper, a multiphase bearingless motor (MBLM) with a single set of half-coiled winding is proposed, with advantages such as simpler construction and capability of fault-tolerant operation, comparing with the traditional BLM with dual groups of three-phase windings. The magnetomotive force distribution of the half-coiled winding is analyzed. Then, the winding configuration of a five-phase permanent-magnet bearingless motor is introduced, and the inductance of the MBLM is deduced by the modified winding function approach and verified by finite-element analysis. Furthermore, the control system is proposed based on the derived voltage model, torque model, and suspension force model, considering rotor eccentricity. Finally, static and dynamic experiments are provided on a prototype motor to verify the validity of the analysis.

Fault-Tolerant Control of Five-Phase Induction Motor Under Single-Phase Open

This paper deals with fault-tolerant control of five-phase induction motor (IM) drives under single-phase open. By exploiting a decoupled model for five-phase IM under fault, the indirect field-oriented control ensures that electromagnetic torque oscillations are reduced by particular magnitude ratio currents. The control techniques are developed by the third harmonic current injection, in order to improve electromagnetic torque density. Furthermore, Proportional Resonant (PR) regulator is adopted to realize excellent current tracking performance in the phase frame, compared with Proportional Integral (PI) and hysteresis regulators. The analysis and experimental results confirm the validity of fault-tolerant control under single-phase open.

Analysis and control of seven-phase permanent-magnet bearingless motor with single set of half-coiled winding

In this paper, a seven-phase inset-type permanent magnetic bearingless motor is proposed with characters as the treble frequency suspension force compensation and elimination of the affection of the third plane to the suspension plane. The winding configuration and harmonic distribution are presented. Then, the analysis formulations of inductance and suspension force of the proposed motor are presented and verified by Finite Element Analysis (FEA). Furthermore, the control system is proposed based on the derived voltage model, torque model and suspension force model with the rotor eccentricity being considered. Finally, the Simulink simulation is provided on a prototype motor to verify the validity of the analysis.

Research of sensorless control for multiphase induction motor based on high frequency injection signal technique

This paper introduces multiphase induction motor drives system under sensorless conditions, which is simulated and analyzed by utilizing its multiple control freedoms in the mode of high frequency signal injection. In this method, because nine phase induction motor have four orthogonal d-q planes compared to traditional three phase induction motor, so high harmonic plane can be used for other applications, for example, extracting rotor position based on high frequency injection signal technique. In the multiphase induction motor, inductance value is smaller in the high harmonic plane contrast to fundamental plane, in other words, it can get larger current signal amplitude under the same voltage amplitude, reducing the difficulty of the position signal extraction. changing rotor slot numbers will affect the air-gap length distribution, and it can be concluded that there is a saliency in the d7-q7 plane through modulation of rotor slots. The module is simulated in the environment of simulink and ansoft.

Improved Sliding-Mode Observer for sensorless control of five-phase induction motor

This paper proposes an improved Sliding-Mode Observer (SMO) for the sensorless control of a five-phase induction motor, which substitutes a sigmod function for the sign function. The conventional SMO is robust against parameter variations and disturbances, however, it has serious chattering problem in the steady state. The proposed method is utilized to reduce the chattering, and the rotor flux is also obtained from SMO for direct field oriented control. The convergence of the improved SMO is analyzed, and sufficient conditions are given to prove the stability. Simulation and experimental results are verified the effectiveness of the proposed method.

Analysis of Half-coiled Short-pitch Windings with Different Phase Belt for Multiphase Bearingless Motor

The analysis and comparation of the half-coiled short-pitch windings with different phase belt are presented in the paper. The half-coiled short-pitch windings can supply the odd and even harmonics simultaneously, which can be applied in multiphase bearingless motor (MBLM). The space harmonic distribution of the half-coiled short-pitch windings with two kinds of phase belt is studied wi th respect to different coil pitch, and the suitable coil pitch can be selected from the analysis results to reduce the additional radial force and torque pulse. The two kinds of half-coiled short-pitch windings are applied to the five- and six-phase bearingless motor, and the comparation from the Finite Element Method (FEM) results shows that the winding with 2π/m phase belt is fit for the five phase bearingless motor and the winding with π/m phase belt is suitable for the six phase bearingless motor. Finally, a five phase surface-mounted permanent magnet (PM) bearingless motor is built and the experimental results are presented to verify the validity and feasibility of the analysis. The results presented in this paper will give useful guidelines for design optimization of the MBLM.

Sensorless Vector Control of Five-phase Induction Motor under Open-phases Fault

Abstract—This article deals with proposed solutions for five-phase induction motor drives, specifically aimed to sensorless vector control under an open-phases fault. Exploiting the modified transformation matrices for dual planes, the motor model in the synchronous frame is established under open phases. Torque ripple is reduced by particular magnitude ratio currents. Furthermore, the third harmonic current is used to improve iron utilization and torque density. The proposed sliding-mode observer method for wide-range speed estimation combined with online resistance identification is investigated, especially for low-speed operation. Experimental tests are performed to validate the effectiveness of the proposed method.

Analysis and simulation of a 7-phase PM bearingless motor

A multiphase bearingless motor with single set of winding has simpler construction, higher power ratings with lower voltage limited devices and better fault tolerance. Additionally, comparing with the traditional surface-mounted PM rotor configuration, there are more advantages for the interior PM rotor configuration, such as, larger suspension force with the increased inductance of suspension winding, avoiding the falling-off of PM during the high speed revolving. Taking a 7-phase interior PM bearingless motor (IPMBLM) for example, the derived general analytical model of inductance matrices is proposed and FEA simulation results validated the proposed model. Additionally, the SIMULINK simulation results certify the feasibility of the IPMBLM.