Extended state observer-based vector control for PMSM drive system with single phase current sensor

© 2017 IEEE. A novel extended state observer (ESO)-based vector control (VC) strategy is developed for permanent magnet synchronous motor (PMSM) drive systems with only one phase current sensor. Generally, to achieve high precision control, two phase current sensors are indispensable for successful operation of the feedback control. In response to a phase current sensor fault, by use of technique of ESO, a new observer for estimating both the remaining two phase currents and time-varying stator resistance is put forward. To improve the performance and decrease system high frequency vibration, a nonlinear exponential function is used to replace the switch function in conventional ESO. The resultant ESO-based VC strategy for PMSM drive system with single phase current sensor has strong robustness and satisfactory control performance. Numerical simulation validates the feasibility and effectiveness of the proposed scheme

Fault Diagnosis in Medium Voltage Drive Based on Combination of Wavelet transform and Support Vector Machine

Nowadays, Medium Voltage Drive (MVD) has been widely applied in the field of high-powered motor speed-regulation. These types of converter use a lot of insulated gate bipolar translators (IGBTs). So it is very important to find an effective way to diagnose IGBT open-circuit faults. This study describes a method of diagnosis for IGBT open-circuit faults in MVD whose topology is cell series of multi-level. This method combines wavelet transform (WT) and support vector machine (SVM). The wavelet transform is used to extract fault features and SVM is used to classify the fault states of a single power unit. Then, the trained SVM classifier is used to scan all power units of MVD sequentially. Results of simulation on the platform of MATLAB/Simulink show that this method has a good diagnosis capability. It can diagnose the IGBT open-circuit faults of the whole inverter system, and diagnosis accuracy is up to 96%. So, this method has a good application prospect

Current sensorless model predictive torque control based on adaptive backstepping observer for PMSM drives

A novel adaptive backstepping observer is proposed and model predictive torque control (MPTC) strategy is considered for three-phase permanent magnet synchronous motor (PMSM) drives without any current sensor. Generally, instantaneous stator currents are required for successful operation of MPTC. If the stator current sensors fail, the most common technique for reconstructing stator currents mainly focuses on using information from a single current sensor in the DC-link of an inverter. Nevertheless, the existence of immeasurable regions in the output voltage hexagon results in that the three-phase currents will not be reliably detected since one or more of the active state vectors are not applied long enough to insure accurate measurements. In addition, the technique may suffer from the very noisy of DC-link current feedback. To avoid these drawbacks, making use of the technique of adaptive backstepping, a novel observer is proposed. The designed observer can be capable of concurrent estimation of stator currents and resistance under the assumption that rotor speed and inverter output voltage as well as DC-link voltage are available for measurement. Stability and convergence of the observer are analytically verified based on Lyapunov stability theory. In order to reduce the torque & flux ripples and improve drives control performance, MPTC strategy is employed. The proposed algorithm is less complicated and its implement is relatively easy. It can ensure that the whole drives system achieves satisfactory torque & speed control and strong robustness. Extensive simulation validates the feasibility and effectiveness of the proposed scheme

Independent current control of dual parallel SRM drive using a public current sensor

Switched reluctance motors (SRMs) have been considered a potential candidate for automotive applications due to its rare-earth-free feature and wide speed range. Conventionally, a current sensor is installed in each phase for the current regulation control, which will considerably add the cost and volume to multimotor drives. This paper proposes an independent current control technique for dual parallel SRM drives using only one current sensor. In order to identify the individual motor currents from the public current, a pulse injection scheme is developed accordingly. Two pulses are individually injected into the lower transistors of the dual converter in the excitation regions and the fixed current sampling points triggered by the injected pulse are presented for motor current identification. The independent current control for the dual SRM can be directly implemented by the public current sensing, although the motor parameters are different. The developed system requires only one current sensor without additional hardware or reduced system performance. The simulation and experimental results on parallel 750 W and 150 W three-phase 12/8 SRM drives are presented to confirm the effectiveness of the proposed method. With this scheme, the dual-motor drive can be more compact and cost effective for traction drive applications

GFTSM-based Model Predictive Torque Control for PMSM Drive System With Single Phase Current Sensor

Copyright © 2017 Acta Automatica Sinica. All rights reserved. A global fast terminal sliding mode (GFTSM)-based model predictive torque control (MPTC) strategy is developed for permanent magnet synchronous motor (PMSM) drive system with only one phase current sensor. Generally two phase-current sensors are indispensable for MPTC. In response to only one phase current sensor available and the change of stator resistance, a novel adaptive observer for estimating the remaining two phase currents and time-varying stator resistance is proposed to perform MPTC. Moreover, in view of the variation of system parameters and external disturbance, a new GFTSM-based speed regulator is synthesized to enhance the drive system robustness. In this paper, the GFTSM, based on sliding mode theory, employs the fast terminal sliding mode in both the reaching stage and the sliding stage. The resultant GFTSM-based MPTC PMSM drive system with single phase current sensor has excellent dynamical performance which is very close to the GFTSM-based MPTC PMSM drive system with two-phase current sensors. On the other hand, compared with proportional-integral (PI)-based and sliding mode (SM)-based MPTC PMSM drive systems, it possesses better dynamical response and stronger robustness as well as smaller total harmonic distortion (THD) index of three-phase stator currents in the presence of variation of load torque. The simulation results validate the feasibility and efiectiveness of the proposed scheme