New reaching law control for permanent magnet synchronous motor with extended disturbance observer

In order to improve the anti-disturbance performance of permanent magnet synchronous motor (PMSM) servo system, a sliding-mode control strategy using a new reaching law (NRL) is proposed. The NRL incorporates power term and switching gain term of the system state variables into the conventional exponential reaching law (CERL), which can effectively suppress the sliding-mode chattering and increase the convergence rate of system state reaching sliding-mode surface. Based on this new reaching law, a sliding-mode speed controller (SMSC) of PMSM is designed. At the same time, to solve the chattering problem caused by the large sliding-mode switching gain, an anti-disturbance sliding-mode speed controller method with an extended sliding-mode disturbance observer (ESMDO), called SMSC+ESMDO method, is developed. The sliding-mode disturbance observer is designed to accurately estimate the motor speed and external load disturbances, and the disturbance estimator is used as a feed-forward to compensate the sliding-mode speed controller (SMSC) to improve the system robustness and reduce the system chattering. Simulation and experimental results show that the proposed compound sliding-mode control strategy can effectively improve the dynamic performance and robustness of the system compared with the PI controller

Multirate input based quasi-sliding mode control for permanent magnet synchronous motor

Permanent magnet synchronous motor field oriented control system often uses dual-loop (speed and current) cascade structure, and the dynamics speeds of the two loops mismatch. The motor’s mechanical and electrical subsystems have the typical multirate characteristics. Based on the multirate control theory, this paper proposes multirate input quasi-sliding mode algorithm for the speed control loop. Under the situation of the output data loss, the proposed algorithm builds the extended input vector with the output prediction information. Due to the extended input vector, the proposed algorithm reduces the system steady state chatterring, and then improves the performance of the whole system. Simulation and experimental results demonstrate the effectiveness of the proposed algorithm

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

Design of second order sliding mode observer based equivalent Back-EMF for rotor position estimation of PMSM

This study introduces a scheme to estimate rotor position by the use of an Equal electromotive force (EMF) model of a synchronous machine. This use could be substituted by a sliding-mode observer (SMO) according to an equal EMF for superior reference speed tracking. There is an algorithm of the second order sliding-mode-control (SO-SMC) in controlling speed of permanent magnet synchronous motor (PMSM). This is by the use of the proportional plus-integral PI control sliding plane. The current work discusses the PMSM, which follows field-oriented appears. In addition, there are SO-SMC laws and PI sliding plans. This paper shows that the proposed high-speed PMSM sensorless speed control is valid by MATLAB simulations

Self organizing fuzzy sliding mode controller for the position control of a permanent magnet synchronous motor drive

AbstractIn this paper, a self organizing fuzzy sliding mode controller (SOFSMC) which emulates the fuzzy controller with gain auto-tuning is proposed for a permanent magnet synchronous motor (PMSM) drive. The proposed controller is used for the position control of the PMSM drive. The performance and robustness of the control system is tested for nonlinear motor load torque disturbance and parameter variations. It has a novel gain self organizing strategy in response to the transient or tracking responses requirement. To illustrate the performance of the proposed controller, the simulation studies are presented separately for the SOFSMC and the fuzzy controller with gain auto-tuning. The results are compared with each other and discussed in detail. Simulation results showing the effectiveness of the proposed control system are confirmed under the different position changes

Improved Deadbeat Predictive Current Control of Permanent Magnet Synchronous Motor Using a Novel Stator Current and Disturbance Observer

Thanks to the merits of superior dynamic response capability and current tracking performance, the deadbeat predictive current control (DPCC) has become a research hotspot for the permanent magnet synchronous motor (PMSM) drive system. However, DPCC is a model parameter sensitive control method. If there is a motor parameter mismatch, the performance of the DPCC drive system in terms of expected voltage vector, current harmonics, and torque ripple would be influenced. In this paper, firstly, a novel power sliding mode reaching law is proposed, which shortens the convergence time of the system state no matter what the initial state is. Then, an improved non-homogeneous disturbance observer (NHDO) with the proposed power sliding mode reaching law is established, which guarantees d-q axis current errors converge to zero when the PMSM drive system suffers uncertain disturbances, such as motor parameter mismatch. Finally, an improved DPCC using the novel stator current and disturbance observer, which includes the proposed power sliding mode reaching law and NHDO, is established. Hence the accuracy of the predicted current increases significantly, and voltage vectors can be immediately compensated once disturbances occur. Both simulation and platform experiments verify that the improved DPCC can maintain the current tracking performance with lower current ripples than the traditional DPCC when the major motor parameters mismatch. The proposed novel stator current and disturbance observer may also enhance the PMSM's drive performance under other control strategies

Anti-disturbance sliding mode based deadbeat direct torque control for PMSM speed regulation system

Deadbeat direct torque control (DBDTC) calculates the voltage vector based on the motor mathematical model and tracks the torque and flux reference within only one sampling cycle. However, in the traditional DBDTC, the reference torque is generated by a speed PI controller, which presents a low dynamic and poor precision, particularly under external disturbances. To sort out this issue, this paper proposes an improved DBDTC control method basing on the sliding mode strategy. First, an anti-disturbance sliding mode controller (ASMC) is presented which is superior in offering a fast and accurate reference torque for DBDTC. Along the way, an extended sliding mode disturbance observer is introduced which estimates total disturbances and compensates the sliding mode controller. To reduce the chattering of sliding mode control, a novel reaching law is proposed. This novel reaching law introduces system state variable in the exponential terms of power reaching law, and meanwhile including an adaptive exponential reaching action. By this means, it increases system convergence rate to the sliding mode surface while suppressing sliding mode chattering. Finally, both simulation and experimental results show that the proposed control method has better performance in terms of torque ripple reduction, speed dynamic response

A Composite Sliding Mode Control for SPMSM Drives Based on a New Hybrid Reaching Law with Disturbance Compensation

This article presents a composite sliding mode control (CSMC) method for speed control of surface-mounted permanent magnet synchronous motors (SPMSMs). The proposed CSMC consists of a new sliding mode control (SMC) based on a novel hybrid reaching law (HRL) and an extended sliding mode disturbance observer (ESMDO). The new HRL is composed of two parts: A terminal reaching part and an exponential plus proportional reaching part. It can effectively suppress the chattering and reduce the reaching time compared with the conventional constant plus proportional rate reaching law (CPRL). The ESMDO is designed based on CPRL. It can estimate the extra chattering produced by the drive system's lumped disturbance and compensate for the controller's output. Based on the proposed new SMC and ESMDO, an antidisturbance sliding mode speed controller is designed to improve the performance of SPMSM drive systems. The performance of the proposed method has been validated experimentally and compared with the CPRL-based SMC methods under different conditions