Review of Field Weakening Control Strategies of Permanent Magnet Synchronous Motors

Due to high power density,high efficiency,and accurate control performance,permanent magnet synchronous motors(PMSMs)have been widely adopted in equipment manufacturing and energy transformation fields.To expand the speed range under finite DC-bus voltage,extensive research on field weakening(FW)control strategies has been conducted.This paper summarizes the major FW control strategies of PMSMs,which are categorized into calculation-based methods,voltage closed-loop control methods,and model predictive control related methods.The existing strategies are analyzed and compared according to performance,robustness,and execution difficulty,which can facilitate the implementation of FW control.

A Novel Flux-weakening Control Method with Quadrature Voltage Constrain for Electrolytic Capacitorless PMSM Drives

In electrolytic capacitorless permanent magnet synchronous motor(PMSM) drives, the DC-link voltage will fluctuate in a wide range due to the use of slim film capacitor. When the flux-weakening current is lower than-ψf/Ld during the high speed operation, the flux-weakening control loop will transform to a positive feedback mode, which means the reduction of flux-weakening current will lead to the acceleration of the voltage saturation, thus the whole system will be unstable. In order to solve this issue, this paper proposes a novel flux-weakening method for electrolytic capacitorless motor drives to maintain a negative feedback characteristic of the control loop during high speed operation. Based on the analysis of the instability mechanism in flux-weakening region, a quadrature voltage constrain mechanism is constructed to stabilize the system.Meanwhile, the parameters of the controller are theoretically designed for easier industrial application. The proposed algorithm is implemented on a 1.5 kW electrolytic capacitorless PMSM drive to verify the effectiveness of the flux-weakening performance.

A Review of Sensorless Control Methods for AC Motor Drives

In recent years,the application of sensorless AC motor drives is expanding in areas ranging from industrial applications to household electrical appliances.As is well known,the advantages of sensorless motor drives include lower cost,increased reliability,reduced hardware complexity,better noise immunity,and less maintenance requirements.With the development of modern industrial automation,more advanced sensorless control strategies are needed to meet the requirements of applications.For sensorless motor drives at low-and zero-speed operation,inverter nonlinearities and motor parameter variation have significant impact on the stability of control system.Meanwhile,high observer’s bandwidth is required in high-speed region.This paper introduces the state of art of recent progress in sensorless AC motor drives.In addition,this paper presents the sensorless control strategies we investigated for practical industrial and household applications.Both advanced sensorless drives of induction motor(IM)and permanent magnet synchronous motor(PMSM)are presented in this paper.

Message from Editors

IN recent years,4th Industrial Revolution and Industry 4.0 have swept the world and deeply influenced the development of global industry market.This movement arises wide attention to electric motor drive system which is playing an increasing important role in energy consumption transformation and environment protection.Amid this tremendous change in industry field,the concept of high-efficient,energy-saving and intelligent motor system has been proposed.On one hand,motor system with advantages such as low vibration,low noise,weak magnetic interference,renewable utilization capacity,high-efficiency and high-reliability could promote the progress of major industries such as mining,renewable energy and cutting-edged equipment manufacturing.On the other hand,the realization of intelligent and automated operations of motor drive system would help boosting the automation of industrial production.

Message from Editors

WITH the depletion of the traditional fossil energy and the increasingly serious problem of global warming,the development and utilization of new energy has gradually become the focus of attention.One of the urgent problems is how to convert new energy into stable and efficient electricity.Therefore,the research on converters have been focused on,including topology structure and control method.In addition,as one of the carriers of electric energy application,the motor system can be optimized in a variety of ways to obtain the maximum utilization of electric energy,such as the improvement of the mechanical structure of the motor and the optimization of the control.

Self-Adaptive Stepsize Affine Projection Based Parameter Estimation of IPMSM Using Square-Wave Current Injection

Affine projection algorithm(APA)has been used to estimate the parameters of interior permanent magnet synchronous motor(IPMSM).However,there is not a strict guideline of choosing the stepsize of this algorithm to make sure that the results of parameter estimation are convergent.In order to solve such problem,self-adaptive stepsize affine projection algorithm for parameter estimation of IPMSM is proposed in this paper.Compared with traditional affine projection algorithm,this method can obtain the stepsize automatically based on the operation condition,which can ensure the convergence and celerity of the process of parameter estimation.Then,on the basis of self-adaptive stepsize affine projection algorithm,a novel parameter estimation method based on square-wave current injection is proposed.By this method,the error of estimated parameter caused by stator resistance,linkage magnetic flux and dead-time voltage can be reduced effectively.Finally,the proposed parameter estimation method is verified by experiments on a 2.2-kW IPMSM drive platform.

Message from Editors

SWITCHED reluctance motor(SRM)is a doubly salient electric machine that relies on reluctance torque to rotate rather than electromagnetic torque,as implied on the name.The term switch comes from the fact that the motor depends heavily on power switches for its operation.This was the reason that slowed the development of SRM since micro and power electronics were not so advanced.

Review of Inductance Identification Methods Considering Inverter Nonlinearity for PMSM

Permanent magnet synchronous motors(PMSMs)are widely used in high-power-density and flexible control methods.Generally,the inductance changes significantly in real-time machine operations because of magnetic saturation and coupling effects.Therefore,the identification of inductance is crucial for PMSM control.Existing inductance identification methods are primarily based on the voltage source inverter(VSI),making inverter nonlinearity one of the main error sources in inductance identification.To improve the accuracy of inductance identification,it is necessary to compensate for the inverter nonlinearity effect.In this study,an overview of the PMSM inductance identification and the related inverter nonlinearity self-learning methods are presented.

Review of Parameter Identification and Sensorless Control Methods for Synchronous Reluctance Machines

Synchronous reluctance machines(SynRMs)have drawn increasing attention in recent years owing to their advantages such as low cost,simple structure,ease of manufacture,and high robustness.The main obstacle to the promotion of SynRMs is severe parameter nonlinearity,which deteriorates drive performance.Sensorless control methods for SynRMs are critical technologies that can broaden the industrial applications of SynRMs.Various methods of parameter identification and sensorless control strategies are reviewed and discussed,including self-commissioning,which is analyzed in detail.Furthermore,sensorless control strategies that can improve the industrial application of SynRMs are described.Finally,future research trends concerning SynRMs are analyzed and discussed.

Saliency-Based Position Sensorless Control Methods for PMSM Drives-a Review

Permanent magnet synchronous motor(PMSM)drives are finding expanded use for industrial and domestic drive applications.With the distinguished characteristics such as reduced cost and increased reliability and robustness,position sensorless(self-sensing)control techniques have been good candidates for reliable and costless PMSM drives.The saliency-tracking based techniques further bring the expansion of applications with the extended controllable sensorless operating speed range.This paper presents a review on state of the art techniques for position sensorless drives using the saliency-tracking based methods.The signal injection methods and the future scope of research including the dynamic bandwidth improvement and the acoustic noise reduction are discussed.