Robust Speed Control With Disturbance Rejection for Surface-mounted Permanent Magnet Synchronous Motor

The Permanent Magnet Synchronous Motor (PMSM) are emerging as one of the most important categories of AC machine drives. Therefore, different control methods are used for speed control of PMSM. In this paper, sliding mode and Extended state observer (ESO) are used to improve the speed control of the PMSM drive system. A sliding mode controller is employed in the outer speed control loop for tracking the speed of PMSM. Load torque disturbance is estimated using ESO. Performance evaluation of the sliding mode controller with ESO is compared with the conventional speed controller using PI. Better speed tracking accuracy is obtained for sliding mode controller than conventional PI controller

In recent years, there has been a significant focus on synchronous reluctance motors (SynRM) owing to their impressive efficiency and absence of magnetic material. Although the SynRM shows great potential for use in electric vehicles, its widespread adoption is limited by unmodeled dynamics and external disturbances. Moreover, the uncertainty factor significantly restricts SynRM's peak efficiency and superior control performance, leading to an unjustifiable current loop reference command. To address these issues, this work presents various new research contributions which focus on the robust control of SynRM to optimize performance through the novel reaching law-based sliding mode control. Initially, a novel advanced sliding mode control reaching law (ASMCRL) with adaptive gain is proposed, to enhance the acceleration of the system state reaching the sliding surface. After that, an extended state observer (ESO) is designed to estimate and compensate for the overall disturbances of the system. Finally, the ASMCRL and ESO are integrated to design two nonlinear controllers namely, the disturbance-rejection sliding mode controller (DRSMC) and the disturbance-rejection sliding mode speed regulator (DRSMSR) for SynRM. The proposed DRSMSR eliminates the steady-state error and eradicates inherent chattering in DRSMC. Moreover, this yields a system trajectory that converges to a predetermined proximity of the sliding surface, irrespective of any lumped disturbances. The steady-state error of DRSMSR is less as compared to DRSMC. Furthermore, the speed response of this technique is 22.62% faster as compared to the state-of-the-art finite-time adaptive terminal sliding mode control. Additionally, the asymptotic stability of the proposed system is validated using Lyapunov's theorem. Thus the experimental results demonstrate the effectiveness and robustness of the proposed approach.

In order to achieve speed control of high-speed permanent magnet synchronous motor with high precision, the sliding mode control (SMC) is usually adopted. However, the inherent chattering phenomenon affects the speed control performance. In order to solve this problem, a composite speed regulator is proposed in this paper, which is made up of two parts: the adaptive full-order SMC and extended state observer (ESO). Switching gain adaption law is proposed for minimizing chattering as much as possible while ensuring the robustness of sliding mode control. The total disturbance is estimated by the ESO and through feedforward, thus improving the system anti-disturbance ability. Finally, the effectiveness of the proposed speed regulator has been validated in the test bench.

This paper presents a comprehensive study on a novel voltage injection based offline parameter identification method for surface mounted permanent magnet synchronous motors (SPMSMs). It gives solutions to obtain stator resistance, d- and q-axes inductances, and permanent magnet (PM) flux linkage that are totally independent of current and speed controllers, and it is able to track variations in q-axis inductance caused by magnetic saturation. With the proposed voltage amplitude selection strategies, a closed-loop-like current and speed control is achieved throughout the identification process. It provides a marked difference compared with the existing methods that are based on open-loop voltage injection and renders a more simplified and industry-friendly solution compared with methods that rely on controllers. Inverter nonlinearity effect compensation is not required because its voltage error is removed by enabling the motor to function at a designed routine. The proposed method is validated through two SPMSMs with different power rates. It shows that the required parameters can be accurately identified and the proportional-integral current controller auto-tuning is achieved only with very limited motor data such as rated current and number of pole pairs.

In speed control systems, which is desirable is that the speed of a controlled object should track the reference speed as fast as possible and at the same time should provide good robustness to load variations. As far as conventional PI controllers are concerned, once their parameters are tuned for solely one operating condition, they remain constant during the whole operational cycle and therefore, a poor controller performance may arise unexpectedly when the operating condition is changed. To overcome this problem, a PI controller incorporated by fuzzy logic controller (FLC) is introduced in this paper for the speed control of a permanent magnet synchronous motor (PMSM). In the proposed control schema, the parameters of the PI controller are determined online based on the error signal and its time derivative by means of a PD-type FLC, which has separate two rule bases, the former of which is responsible for P gain and the latter is for I gain. According to the computer simulations performed under the same conditions, the obtained results based on the proposed method are more promising than those obtained by the conventional PI controller with fixed parameters.

This paper is concerned with robust vector control of a permanent magnet synchronous motor (PM-SM) using a fix- point DSP based computing architecture. Speed control systems are analyzed for different operation conditions. A hardware architecture was developed based on a TMS320C5x fixed-point processor, a PWM control unit realized in FPGA technology, an interfacing unit to the incremental encoder and A/D converters for the stator-phase current inputs, a high speed TDM-type serial bus and an emulating and debugging driver. The software was written in both, DSP-assembler language for acquisition and communication programs and in C language for the control algorithm computation. The computing system solution based on a minimal hardware configuration offers a flexible solution for different control strategies applied to a large scale of driving systems. The designing procedure of the speed controllers can be very difficult, if a complex mathematical model of the plant is used. But robust controllers keep the dynamic and stability performance of the controlled system even if structured or unstructured uncertainties appear. That's why, robust speed controllers can be designed by using simplified models of the PM-SM machines, and has to be used in a complex structure based on the field-oriented control (FOC) principle (2). Thus, the requirements of a digital control application are: a flexible control structure, reduced hardware configuration and a good dynamic behavior of the controlled process. The designing procedure of the optimal H∞ controller and the robust control of the driving system will be accomplished by simulated and experimental results. Based on the results obtained, advantages and disadvantages of the proposed control structures will be discussed.

Disturbances and uncertainties are the main concerns in control systems. To obtain this information in real time, the extended state observer is proposed as the core of the active disturbance rejection control. However, the estimation errors of extended state observer cannot converge to zero in the presents of unknown but bounded disturbances, which will bring unexpected tracking errors to the closed-loop system. By taking advantage of the linear extended state observer and the super-twisting algorithm, the super-twisting extended state observer is proposed to deal with the non-diminishing second-order derivable disturbances in this paper. The asymptotic convergence of the super-twisting extended state observer and the controller are proved by the Lyapunov method. Moreover, the effectiveness and robustness of the super-twisting extended state observer are verified by simulation analysis. Simulation results show that the proposed super-twisting extended state observer maintains the minimized estimation error with less settling time compared the with linear extended state observer. The tracking performance of the controller with the proposed observer is greatly improved.

This paper proposes an online gain tuning algorithm for a robust sliding mode speed controller of surface-mounted permanent magnet synchronous motor (SPMSM) drives. The proposed controller is constructed by a fuzzy neural network control (FNNC) term and a sliding mode control (SMC) term. Based on a fuzzy neural network, the first term is designed to approximate the nonlinear factors while the second term is used to stabilize the system dynamics by employing an online tuning rule. Therefore, unlike conventional speed controllers, the proposed control scheme does not require any knowledge of the system parameters. As a result, it is very robust to system parameter variations. The stability evaluation of the proposed control system is fully described based on the Lyapunov theory and related lemmas. For comparison purposes, a conventional sliding mode control (SMC) scheme is also tested under the same conditions as the proposed control method. It can be seen from the experimental results that the proposed SMC scheme exhibits better control performance (i.e., faster and more robust dynamic behavior, and a smaller steady-state error) than the conventional SMC method.

Active disturbance rejection control is implemented in a LC-filtered surface-mounted permanent magnet synchronous motor (SPMSM) drive system to enhance current control dynamics. However, the combined effects of computation one-beat delay and the pulse-width modulation zero-order hold (ZOH) effect significantly degrade system stability and dynamic performance. To address these limitations, an improved predictive extended state observer (ESO) with an accurate ZOH discretization method is proposed to ensure fast and robust dynamic performance. The predictive ESO predicts one beat to compensate for the delay effect, while the ZOH discretization yields a more precise discrete dynamic model of the system. These combined improvements substantially enhance the system’s phase and gain margins, leading to superior dynamic performance. Furthermore, a discrete-domain transfer function of the control system is analytically derived, with the control parameters systematically designed using frequency-domain analysis to guarantee robust performance. Experimental validation on a LC-filtered SPMSM drive system demonstrates remarkable enhancement in current control dynamics while maintaining sufficient robustness.

<p>As a part of last-mile transportation, electric three-wheelers, popularly known as trikes, are considered as an important aspect of the future of the auto industry. The appropriate choice of electric traction motor drive is imperative to the design of an electric motor power train. In this paper, six main types of sinusoidal-fed electric motor power trains—Ferrite-Assisted Synchronous Reluctance Motor (FASRM), Synchronous Reluctance Motor (SyncRelM), Ferrite-based Spoke motor, Ferrite-based Surface-Mounted Permanent Magnet Synchronous Motor (SMPMSM), Wound-Field Synchronous Motor (WFSM), and Induction Motor (IM)—are compared for their performance in electric trike applications. The permanent magnet machines presented here utilize ferrite magnets, in line with the recent trend of not using rare-earth magnets. The comprehensive comparative analysis establishes that SyncRelM, FASRM, and Spoke motors are superior in terms of overall electromagnetic, thermal, and vibration performance. This paper also focuses on an optimal design of the FASRM due to its high torque density, lower torque ripple, and minimal use of ferrite magnets. A Design of Experiments (DoE)-based statistical analysis tool is used to identify the key parameters needed for robust motor performance in the optimization step. Furthermore, an Extreme Learning Machine (ELM)-based interpolation technique is employed for estimating the performance parameters during each step of the optimization routine. A 1.2 kW FASR motor prototype is developed and tested. A comparison of Finite-Element-Analysis-based modeling results is presented along with Indian drive-cycle results for the FASRM for trike application.</p>

This paper presents the fuzzy logic-based speed control of an interior permanent magnet synchronous motor (IPMSM) drive. The fundamentals of fuzzy logic algorithms related to motor control applications are illustrated. A new fuzzy speed controller for the IPMSM drive is designed. The efficacy of the proposed fuzzy logic controller (FLC) based IPMSM drive is verified by simulation as well as experimental results at different dynamic operating conditions. The fuzzy logic controller is found to be robust for application in the IPMSM drive. The complete vector control scheme incorporating the FLC is implemented in real-time using a digital signal processor (DSP) controller board DS 1102 in a laboratory 1 hp interior permanent magnet synchronous motor.

This paper presents a more robust model predictive direct speed control based on the third-order extended state observer (RMPDSC-TESO) method for surface-mounted permanent magnet synchronous motor (SPMSM) servo systems to attain a superior disturbance rejection performance and simplify parameter adjustment. First, by taking advantage of the fast current response to reconstruct the load disturbance, the disturbances in the motion and voltage equations are transformed into a unified equivalent current disturbance, thereby constructing a second-order speed ultra-local model. Subsequently, a TESO that only requires consideration of a single control parameter is adopted to estimate the speed control model's lumped disturbance, improving the system's robustness. Moreover, the deadbeat method is adopted to obtain the optimal voltage control solution. Then, by conducting derivations on the root locus and disturbance sensitive characteristics, the system's stability, anti-interference performance, and the influence of the input gain on the system's dynamic performance are demonstrated. Finally, experimental verification was carried out on a SPMSM test platform based on a DSP F28379D chip, and the results confirm the effectiveness of this control strategy in terms of dynamic performance and unmodeled disturbance suppression.

In this paper, a rotor flux observer with adaptive interfering signal elimination for sensorless control of surface-mounted permanent magnet synchronous motor (SPMSM) is proposed. As we all known, the rotor flux of SPMSM can be obtained by integrator or closed-loop observer. But the interfering signals, i.e. ramp signal, dc offset and harmonics, always exist in obtained rotor flux due to unknown initial value, integral calculation, current detection errors and inverter nonlinearity. These interfering signals will greatly degrade the sensorless control performance. So an extended master-slave adaptive notch filter (EMS-ANF) with frequency adaptation is proposed to eliminate these interfering signals and extract the accurate fundamental wave of rotor flux. The theoretical analysis indicates that the EMS-ANF can eliminate the dc offset and specific harmonics in input, and avoid the ramp signal caused by integration. Then, based on EMS-ANF, a complete sensorless control scheme for SPMSM is designed. The experimental results under different conditions demonstrate the effectiveness and the superiority of the proposed method.

In order to enhance the dynamic performance and anti-disturbance ability of speed control for a permanent magnet synchronous motor (PMSM), a sliding mode control method based on a PID sliding surface and an improved terminal sliding mode reaching law (ITSMRL) is proposed. Firstly, an ITSMRL is proposed to increase the reaching speed and reduce chattering; moreover, it has been verified that the reaching law (RL) can achieve a sliding mode surface in finite time. Then, based on the dynamic model of PMSMs with uncertainties, an extended state observer (ESO) is used to estimate the lumped disturbance, and it is proven that the estimated error is bounded. Finally, on the basis of the observed feedforward disturbance, to enhance the disturbance rejection ability of PMSMs, a controller that combines the PID sliding mode surface and the ITSMRL is proposed. Moreover, the stability of the closed-loop system is proven. The composite method has the characteristics of a fast reaching speed, small chattering and strong robustness, and is verified by experiments.

Direct torque control (DTC) is one of the most prominent control techniques used by permanent magnet synchronous motor (PMSM) drives in industry applications. Nevertheless, the presence of hysteresis controllers and inaccurate voltage switching table in traditional DTC results in higher torque and flux ripple. This study proposes an enhanced DTC functioned Surface‐mounted PMSM (S‐PMSM) drive with mitigation of torque and flux ripple. The operation relies on generating the reference voltage vector (VV) in a stationary reference frame, which supports control of torque and flux without hysteresis controllers. The reference VV generation is simple and does not affect control robustness. The position of reference VV in a sector is used to build the voltage vector (VV) switching table. As a result, the application of nearest discrete VV to reference VV produces optimal torque and flux control. Moreover, redundant switching combinations of null VV are effectively used for possible minimization of switching frequency of two‐level voltage source inverter (VSI) supplied S‐PMSM drive. Therefore, proposed DTC gains improved S‐PMSM drive response along with switching frequency reduction. In dSPACE‐RTI 1104 platform, experimental response of S‐PMSM drive under various operating conditions have been depicted to highlight the proficiency of proposed DTC in comparison with existing DTC.