Synchronous Motor System Research Articles

Adaptive Capacitor Voltage-Based Model Predictive Control for Open-Winding PMSM System With a Floating Capacitor

In this article, an adaptive capacitor voltage-based model predictive control (ACV-MPC) strategy for the open-winding permanent magnet synchronous motor system with a floating capacitor (FC-OW-PMSM) is proposed. The control precision of the conventional model predictive control (CMPC) strategy is improved by adjusting the capacitor voltage without using high switching frequency methods. The position of voltage vectors (VVs) is uncertain under different capacitor voltages. To establish a unified motion process of the uncertain VVs, the VV trajectories are analyzed. Furthermore, a novel region division scheme is proposed to locate the candidate VV trajectory. To further determine the reference capacitor voltage and select the candidate VVs from the candidate VV trajectory, the proposed scheme is analyzed in each VV trajectory. Finally, a cost function with only one capacitor voltage constraint is carried out to select the optimal VV, and thus, the weighting factors and the complicated iterative process are both avoided. Experimental studies are carried out to verify the effectiveness of the proposed strategy.

Research on Permanent Magnet Synchronous Motor Sensorless Control System Based on Integral Backstepping Controller and Enhanced Linear Extended State Observer

The traditional sensorless control system of permanent magnet synchronous motor (PMSM) has the problems of low estimation accuracy and poor anti-interference ability. Moreover, the position estimation performance is subjected to position harmonic ripples caused by inverter nonlinearities and flux spatial harmonics. To optimize the dynamic performance of the PMSM sensorless control system, this paper proposes a sensorless control scheme that combines integral backstepping control with enhanced linear extended state observer (ELESO). The ELESO consists of two linear extended state observers (LESOs), which estimate the internal and external disturbances of the system, to improve the estimation accuracy of rotor position. Then, the integral backstepping controller processes the estimated rotor position and speed information to obtain d and q-axis voltages. The sensorless control scheme is implemented in the Matlab/Simulink and verified by experiments. The simulation and experiment show that the scheme can effectively suppress load interference and improve control accuracy.

Design of single neuron super-twisting sliding mode controller for permanent magnet synchronous servo motor

Aiming at the control system of permanent magnet synchronous servo motor which is easily affected by external disturbance and parameter uncertainty, a single neuron sliding mode combining single neuron adaptive algorithm and super-twisting sliding mode (STSM) control is proposed. The STSM control is used to overcome the chattering problem in the traditional sliding mode control, and the proportional control and the STSM control are combined to enhance the robustness of the control system. In order to improve the dynamic performance of the system and enhance the anti-disturbance ability of the system, the single neuron adaptive control adopted can adjust the relevant parameters of the designed sliding mode controller online. The simulation and experimental results show that the designed improved sliding mode controller can effectively suppress the chattering of the control system, realize the fast following and no overshoot of the control system, and enhance the robustness of the system.

Three-Level Inverter-PMSM Model Predictive Current Control Based on the Extended Control Set

In the neutral point clamped (NPC) three-level inverter-permanent magnet synchronous motor system, traditional model predictive current control (MPCC) uses the system predictive model to traverse the 27 basic voltage vectors, to achieve the d-q axis current component and neutral point voltage of the multi-objective optimal control. Finite control set model predictive control predicts the state change of the control target at future moments based on a finite number of switching states of the inverter. The control principle of this method is simple and easy to implement, but the control effectiveness of this control strategy is limited because only one basic vector can be selected as the optimum output per control period. In this paper, a model predictive current control strategy based on an extended control set (ECS-MPCC) is proposed, which can improve the control performance of the system by extending the control set to select multiple vectors in a single control period compared to the traditional strategy. In addition, to address the disadvantage of extending virtual space vectors leading to an increase in computation, this paper proposes a fast search method for optimal vector based on region reduction. The proposed method avoids the optimization process traversing all virtual space vectors, thus enabling a fast search for the optimal vector. The experimental results show that the proposed control strategy has good steady-state and dynamic performance.

A sensorless control system of permanent magnet synchronous motor for electric locomotive based on improved high-frequency rotating injection method

The mechanical sensor of electric locomotive is easy to lose, leading to position measurement error, which deteriorates the performance of permanent magnet synchronous motor (PMSM) drive system. Therefore, a limp-home mode based on high-frequency injection sensorless strategy is proposed. The signal processing of conventional high-frequency rotating injection needs several filters, and the delay has an impact on estimated position, which is phase-based demodulation. In this paper, an amplitude-based demodulation strategy is proposed, which needs only one low-pass filter, meanwhile the digital control delay can be canceled automatically. Accordingly, the position estimation precision and robustness can be enhanced with the aid of proposed method. The feasibility and effectiveness of theoretical analysis is verified on an 18-kW PMSM drive system experimental platform.

Sensorless Vector Control System of Synchronous Reluctance Motor Based on Hybrid Control in Full Speed Domain

Sensorless Vector Control System of Synchronous Reluctance Motor Based on Hybrid Control in Full Speed Domain

Adaptive Sliding Mode Control With Disturbance Observer for Speed Regulation System of Permanent Magnet Synchronous Motor

In order to improve the robustness and speed tracking performance of a permanent magnetic synchronous motor (PMSM) system, under the framework of PMSM vector control, a nonlinear speed control method based on improved sliding mode control (SMC) and disturbance observer is proposed in this paper. First, a novel fast reaching law is designed to make the system trajectory reach the sliding mode surface within a finite time and to alleviate the chattering phenomenon. Second, a nonlinear integral terminal sliding mode surface is proposed by introducing sign and fractional error integration, which achieves finite-time convergence of the speed tracking errors and integral errors without the singular problem. Then, based on the proposed reaching law and the proposed sliding mode surface, an adaptive sliding mode speed controller with disturbance observer which adaptively compensates the output of the improved sliding mode speed controller, is developed not only to guarantee the finite-time convergence performance of the state trajectories, but also to demonstrate stronger robustness, higher precision and lower chattering compared to conventional sliding mode controller. Finally, the simulation and experimental results confirm the validity of the proposed method for practical applications.

Fault-Tolerant Current Control of Six-Phase Permanent Magnet Motor With Multifrequency Quasi-Proportional-Resonant Control and Feedforward Compensation for Aerospace Drives

To improve the current tracking performance, this article proposes a new fault-tolerant current control for the six-phase fault-tolerant permanent magnet synchronous motor (FTPMSM) system with multifrequency quasi-proportional-resonant (QPR) control and back electromotive force (EMF) feedforward compensation, which can track the time-varying sinusoidal and nonsinusoidal reference currents in the stationary reference frame (SRF) under normal and fault conditions. First, the multifrequency QPR current controller with shunt topology is proposed to track the time-varying reference current in SRF, which can guarantee the current control performance regardless of the motor speed variation and the load torque change. Second, the optimized feedforward compensation method for the back EMF is proposed to further reduce the steady-state current tracking error, which takes the time delay of the digital implementation into consideration. Finally, the effectiveness of the proposed approach is verified on a 3 kW six-phase FTPMSM platform. The resulting six-phase FTPMSM system with the proposed current control has great current tracking performance, strong robustness to various external/internal disturbance, as well as low computational burden, which can guarantee the multiphase FTPMSM system performance in normal and fault conditions.

Active Damping Control Method for Different Dual-Parallel-SPMSM Systems with Single Inverter

This paper presents a stabilization method for different dual parallel surface permanent magnet synchronous motor (SPMSM) systems with a single inverter. When a single inverter drives two synchronous motors, disturbance can cause a torque difference between the two motors. This can cause the motor's electrical and mechanical resonance. Several damping control methods have been proposed to suppress such resonance. However, such methods consider that the parameters of the two motors are identical. When a single inverter controls two motors with different parameters, the damping control performance deteriorates. Besides, the motor's resonance sound and current ripple increase. To address these problems, this paper proposes a control method for dual-parallel-SPMSM drive systems with a single inverter.

Adaptive nonsingular terminal sliding mode controller for PMSM drive system using modified extended state observer.

In this study, a novel adaptive nonsingular terminal sliding mode (ANTSM) control frame combined with a modified extended state observer (MESO) is presented to enhance the anti-interference performance of the permanent magnet synchronous motor (PMSM) system. In the face of time-varying disturbances with unknown upper bounds, traditional nonsingular terminal sliding mode (NTSM) controllers typically utilize the large control gain to counteract the total disturbance, which will cause unsatisfactory control performances. To address this tough issue, an ANTSM control technique was constructed for the PMSM system by tuning the control gain automatically without overestimation. On this basis, the MESO was adopted to estimate the unknown total disturbance, whose estimation was offset to the ANTSM control input. By applying finite-time techniques, the estimation error will finite-time converge to zero. The proposed MESO has a more rapid estimation speed than the traditional extended state observer (ESO). Finally, the validity of the ANTSM + ESO composite control algorithm is confirmed by comprehensive experiments.

Extended state observer based current-constrained controller for a PMSM system in presence of disturbances: Design, analysis and experiments

Considering overcurrent and total disturbances, i.e. measurement noise, parameter uncertainties, external load torque disturbance etc., a composite current-constrained control method based on non-cascade single-loop speed regulation control structure is adopted for permanent magnet synchronous motor system (PMSMs). First, a tracking state space model is proposed to transfer the matched and mismatched disturbances into a uniform matched disturbance. Second, a third-order extended state observer (ESO) is developed to satisfactorily attenuate the effect of the total disturbances with their estimation values via feedforward compensation, since a tracking differentiator (TD) is designed to arrange the transition process for the reference input signal to balance the contradiction between overshoot and quick response. Third, a composite ESO-based current-constrained controller with a penalty mechanism of q-axis current, constructed by a special nonlinear gain, is designed to deal with the overcurrent of the PMSMs speed regulation. In addition, a finite time bounded stability theory is introduced to analyze the proposed closed-loop speed regulation system. A bench mark experimental set-up based on NI CompactRIO 9045 and LabVIEW for a PMSMs is designed to verify and compare the performances of the proposed composite controller against conventional PID controller. Finally, the simulation and experiment results demonstrate the effectiveness and superiority of the proposed controller.

Simulation Research on Ship-borne PMSM Speed Regulation Control System Based on Fuzzy PID Control

As the important actuator of ship-borne electromechanical equipment such as offshore cranes, the control system of Permanent-magnet synchronous motor (PMSM) is a complex system that features nonlinearity, time-varying parameters, and multi-variable coupling. Due to working in a swing environment, the ship-borne PMSM speed regulation control system is confronted with some problems, such as abrupt load change, external interference signals, motor parameters change, and given signals change frequently. To improve the control performance, this study designs the 2-dimensional Fuzzy PID controller and builds the control system simulation model with a double closed-loop structure in the MATLAB/Simulink. By comparing the control system under various simulation situations, the simulation findings demonstrate that the control system using the Fuzzy PID controller far outperforms the PID controller in terms of control indicators such as stability, tracking ability, and anti-disturbance ability, which can better adapt to working in swing environment.

Research and Realization of Servo Control System Based on Medical Centrifuge

The power of the medical centrifuge is provided by the permanent magnet synchronous motor, so the AC control system of the permanent magnet synchronous motor directly determines the overall performance of the centrifuge. In this paper, the permanent magnet synchronous motor is the controlled object, the DSP28335 is used as the main control chip, and combined with the vector control strategy, the permanent magnet synchronous motor AC servo control system is designed. Finally, according to the design scheme, the soft and hard design of the motor control system is completed, and the system test is carried out. The test results show that the designed servo control system has fast response, good tracking performance, and stable operation, and has a certain market application prospect.

Adaptive LuGre Friction Compensation for Servo System Based on Backstepping Control and Feedforward Control

Aims: The study aims to improve the position control accuracy of a class of permanent magnet synchronous motors under friction. Background: Permanent magnet synchronous motor and servo system are important parts of modern industry, in which the friction effect is a typical nonlinear factor. To overcome the nonlinear friction effect, it is necessary to design a compound feedforward algorithm to improve the motion control accuracy. Objective: The objective of the study is to design a compound adaptive friction feedforward controller to overcome the nonlinear friction effect in the servo system while ensuring tracking accuracy. Methods: A compound algorithm combining velocity-acceleration double feedforward and adaptive friction feedforward is proposed to ensure the control accuracy, and then the backstepping control is used to ensure strict convergence. Finally, the friction parameter observer is used to estimate the parameters, and the performance of the control system is simulated in the Simulink module Results: Compared to Pure Friction Feedforward Compensation (PFFC) and Adaptive Friction Compensation (AFC), Adaptive Backstepping Feedforward Friction Compensation (ABFFC) has a faster convergence speed, higher steady-state accuracy, and less friction nonlinear effect Conclusion: The servo system with adaptive backstepping and feedforward friction compensation improves the accuracy and convergence of control performance. Moreover, the adaptive permanent magnet synchronous motor control system can effectively overcome the nonlinear friction effect.

Characterization and Selection of Probability Density Function in a Discrete Random Switching Period SVPWM Strategy

Aiming at suppressing the switching frequency harmonics in the integrated permanent magnet synchronous motor (PMSM) systems, a discrete random switching period (DRSP) space vector pulse width modulation (SVPWM) technique is proposed in the present study. In the proposed DRSP-SVPWM technique, the switching period is randomized according to a predefined frequency sequence. Accordingly, the narrow-band harmonics of the switching frequency are extended to a wider range. Then, a mathematical correlation between the probability density function and the harmonic distribution is established. Moreover, the effects of discrete uniform and beta distributions on the harmonic spreading are studied. Based on the proposed DRSP-SVPWM technique, the mathematical expression of the harmonic power spectrum is derived, demonstrating the intrinsic dependency between the discrete random factor and the harmonic energy distribution. Finally, a series of simulations and experimental results are compared to evaluate the performance of the proposed technique. The present study is expected to provide a theoretical basis for the design and selection of discrete frequency sequences. Meanwhile, it provides a reference to investigate the random SVPWM and improve noise and electromagnetic interference in power converters.

Nonsmooth Observer-Based Sensorless Speed Control for Permanent Magnet Synchronous Motor

The sensorless speed regulation problem for a surface-mount permanent magnet synchronous motor system is studied in this article. First, a new nonsmooth observer scheme is proposed to estimate the rotor position, speed, and lumped disturbance of the system. Based on the estimated information, a composite speed controller is then designed, in which the nonsmooth control technique is employed in the feedback design, and the estimated value of disturbance is used in the feedforward compensation. By Lyapunov theory, rigorous analysis guarantees the stability of the closed-loop system and shows that the proposed method can enhance the disturbance rejection property of the system. Finally, simulation tests and experiment results are given to verify the effectiveness of the proposed method.

Finite-Time Convergence ESO-Based Nonsingular Fast Terminal Sliding Mode Control for PMSM with Unknown Parameters and Time-Varying Load

In this paper, an extended state observer (ESO)-based nonsingular fast terminal sliding mode (NFTSM) control method is proposed for the speed tracking system of permanent magnet synchronous motor (PMSM) in the present of unknown parameters and time-varying load. Firstly, three finite time convergence ESO (FTCESO) are employed to estimate the lumped disturbances in one speed loop and two current loops, respectively, and the estimates are fed forward to controllers for compensation. Secondly, a NFTSM controller is designed, which can drive the speed of PMSM track in desired speed in finite time. The stability of resulting closed-loop system is proved by using Lyapunov theory. Finally, the simulation and experimental results are compared with the existing methods, and the results show that the proposed method has better performance in tracking different kind of desired speed curves, and also performs better in reducing the chattering phenomenon.

Neural adaptive finite-time dynamic surface control for the PMSM system with time delays and asymmetric time-varying output constraint

This paper presents a neural adaptive finite-time dynamic surface control for the permanent magnet synchronous motor system with time delays and asymmetric time-varying output constraint. The core challenge is how to address the time delays and asymmetric output constraint when designing a finite-time control scheme. Given this, a proper Lyapunov–Krasovskii functional is introduced to address time delays, and a nonlinear transformation function is considered to convert the output-constrained problem into an unconstrained one. Then, a neural adaptive finite-time dynamic surface control approach is devised in the finite-time backstepping framework, which applies neural networks to estimate the unknown nonlinear functions and introduces first-order filters to solve the “explosion of complexity” problems. Furthermore, it is demonstrated that all the signals of the resulting system are finite-time stable and the tracking error converges to a neighborhood of origin in finite time without violating the output constraint. Finally, the simulation results show that the integration of squared error results, the integral of time and absolute error results as well as the integration of absolute value error results of the proposed scheme is smaller than the tested scheme by 0.3458 , 22.2977 , and 2.2513 , respectively, when the time delays are considered. It further elucidates the availability and superiority of the developed method.

A Composite Variable Structure PI Controller for Sensorless Speed Control Systems of IPMSM

In the speed control system of an Interior Permanent Magnet Synchronous Motor (IPMSM) without a speed sensor, PI controllers using only a fixed set of parameters cannot achieve accurate tracking of the estimated speed in a wide speed domain and also suffer from step response overshoot. This paper proposes a Compound Variable Structure PI (CVSPI) controller to improve the system control performance. It can choose whether to include an integral term according to the size of the system deviation to speed up the response. It also introduces a Model Reference Adaptive System (MRAS) speed observer in the controller to estimate the speed and adaptively adjust the size of the anti-integration saturation gain to improve the dynamic response following performance and immunity of the system. A feed-forward link is added for a given input differential to achieve an accurate answer to time-varying inputs. As the linear compensation matrix of the conventional MRAS is a unit matrix, the speed can only be accurately observed in a specific speed range. In this paper, a new linear compensation matrix is designed, and a new speed adaptive law is derived, allowing the improved MRAS to measure speed over a wide range accurately. Simulation results validate the excellent control performance of the CVSPI and the accuracy of the enhanced MRAS over a wide speed range.

Design of Model Predictive Control Weighting Factors for PMSM Using Gaussian Distribution-Based Particle Swarm Optimization

An improved particle swarm optimization (PSO) algorithm based on Gaussian distribution model is proposed to realize the autotuning of weighting factors for the cost function design in the model predictive control method. First, the design principle of the weighting factors in model predictive torque control for permanent magnet synchronous motor system is analyzed. Then, using the root mean square of the current error in the two-phase rotating coordinate system and the system switching frequency as references, the objective function of the particles in the PSO is designed by considering the main control goals of reducing the torque ripple, the current total harmonic distortion, and the switching frequency. The Gaussian individual optimal distribution model is used to update the particle position on the structure of the conventional PSO algorithm. The experimental results show that the proposed method can solve the problem of weighting factors design as it reduces the switching frequency of the system while achieving excellent steady-state performance.