Sensorless Synchronous Reluctance Motor Research Articles

Dead-Time Compensation Using ADALINE for Reduced-Order Observer-Based Sensorless SynRM Drives

The inverter dead time effect is non-negligible for the control performance of sensorless synchronous reluctance motor (SynRM) drives at low speeds. In this paper, a reduced-order observer-based sensorless control method for SynRM drives combined with the adaptive linear neurons (ADALINE)-based dead-time compensation is proposed. The reduced-order observer-based sensorless control method is presented, for which is parameter tuning is easy. On this basis, the dead-time compensation strategy using ADALINE filters is proposed to reduce the voltage harmonics effect on the estimation performance of the reduced-order observer. With ADALINE filters, the sixth current harmonic can be successfully filtered out by compensating the voltage directly or fitting the current to compensate the voltage. In this way, the low-speed estimation performance of the reduced-order observer is improved. The effectiveness of the proposed method is verified on a 3 kW SynRM experimental platform.

Variable-Angle Random High-Frequency Voltage Injection Strategy with Cross-Saturation Effect Compensation for Sensorless Synchronous Reluctance Motor Drives

There are usually noise problems when the position sensorless control of a synchronous reluctance motor (SynRM) is carried out by high-frequency (HF) signal injection method. Due to the special structure, the cross-saturation effect of the SynRM is particularly serious, resulting in reduced position observation accuracy. In this paper, a variable-angle random HF voltage injection strategy with cross-saturation effect compensation is proposed for position sensorless SynRM drives. Random number generation based on the chaotic mapping method is used to generate random HF voltage signals with different frequencies for injection; the current power spectral density (PSD) distribution is extended and the HF noise can be reduced. A control strategy based on variable-angle square-wave injection is proposed to suppress the cross-saturation effect. By measuring the position error curves of different loads off-line and polynomial fitting the curves, the position error is achieved by combining with the corresponding signal demodulation algorithm. The proposed method does not require additional hardware resources and can maintain high control accuracy and robustness. Finally, the effectiveness of the proposed sensorless control strategy is verified on a 3 kW SynRM experimental platform.

Comparison Between UKF and EKF in Sensorless Synchronous Reluctance Motor Drives

Comparison Between UKF and EKF in Sensorless Synchronous Reluctance Motor Drives

Improved Current Regulators for Sensorless Synchronous Reluctance Motor

Improved Current Regulators for Sensorless Synchronous Reluctance Motor

Rotor Position Error Compensation in Sensorless Synchronous Reluctance Motor Drives

A new approach to compensate rotor position errors caused by parameter mismatching in model-based sensorless synchronous reluctance (SynchRel) motor drives is presented in this article. According to the proposed approach, the error in estimating the rotor position is detected by injecting some low-frequency current signals and adjusting the estimated rotor angular position through a gradient descent algorithm until minimizing the ripple generated on the estimated rotational speed. A rotor position correction can be fully online accomplished coping with saturation and cross saturation effects, as well as with unmodeled phenomena and unpredictable variations of the stator resistance with the temperature. The correction procedure can be accelerated by starting from an approximated correction table, which can be offline built using the same technique. The proposed approach neither needs additional current or voltage sensors nor motor design modifications, thus providing an inexpensive mean to improve the control performance and robustness. Although originally conceived to deal with back EMF-based sensorless control techniques, the correction procedure can be extended to other model-based sensorless SynchRel motor drives.

Hybrid Pseudorandom Signal Injection for Position Sensorless SynRM Drives With Acoustic Noise Reduction

The extra acoustic noise caused by the high-frequency (HF) signal injection imposes restrictions on its extensive applications for sensorless synchronous reluctance motor (SynRM) drives. To attenuate the undesired acoustic noise further, a hybrid pseudorandom (PR) signal injection scheme is proposed in this article. The hybrid PR signal injection is implemented by injecting square wave signals chosen in a random manner from a set of signals having either different frequencies or phases from each other. The optimal assembly of hybrid PR signals is designed via current power spectral density (PSD) analysis, aiming at reducing acoustic noise as much as possible. In this way, the proposed scheme achieves success in a massive acoustic noise reduction by means of completely eliminating the discrete harmonics of the current PSD and distributing the current PSD to a wider range. Besides, the low-pass filters used to separate the fundamental frequency component from injected HF components of currents could be eliminated because no discrete harmonics at injected frequencies exist with the proposed hybrid PR signal injection. The validity and superiority of the proposed sensorless control scheme are verified on a 3-kW position sensorless SynRM drive platform.

Sensorless Synchronous Reluctance Motor Drives: A Projection Vector Approach for Stator Resistance Immunity and Parameter Adaptation

This article presents a general projection vector framework for the analysis of flux and position observers applied to sensorless control of synchronous reluctance (SyR) machines, with emphasis to parametric errors sensitivity. The stator resistance immunity property of Adaptive Projection vector for Position error estimation (APP) technique is demonstrated in maximum torque per ampere (MTPA) conditions. Out of MTPA, additional resistance adaption is devised for accurate estimation of stator flux and torque. Alternatively, inductance adaptation might be preferred to resistance's, when dealing with inaccurate motor flux-maps. Inductance adaptation is shown to decrease the steady-state position error. All the proposed APP observers with adaptation techniques are subjected to stability analysis. The merit and the feasibility of the proposed scheme are experimentally demonstrated on a 1.1-kW SyR machine test bench.

Torque Ripples Minimization of Sensorless SynRM Drives for Low-Speed Operation Using Bi-HFSI Scheme

Torque smoothness is a strict requirement for synchronous reluctance motor (SynRM) industrial applications. The speed fluctuations induced by the high-frequency and low-frequency torque ripples deteriorate the drive performance. To suppress high-frequency torque ripples chronically omitted by conventional high-frequency signals injection methods at low-speed operation, this article proposes a bi-axes high-frequency signals injection (Bi-HFSI) scheme. A novel signal injection method is adopted, and the torque power spectrum can be broadened with discrete peaks effectively suppressed. In addition, aiming at decreasing low-frequency torque ripples, the Fourier iterative learning control algorithm that is effective in suppressing periodic disturbance is applied. It is combined with the Bi-HFSI scheme which mainly limits torque ripples at low frequencies including 1st, 2nd, and 6th harmonics. Theoretical analysis is presented, and the proposed method is verified by experiments on a 3-kW SynRM drive platform.

Simulation and Implementation of Predictive Speed Controller and Position Observer for Sensorless Synchronous Reluctance Motors

A position observer and a predictive controller for sensorless synchronous-reluctance-motor (SynRM) drive systems are investigated in this paper. The rotor position observer, based on motor parameters, and stator currents and voltages, was designed and implemented to compute the rotor position. A pole-assignment technique was used to provide similar converging rates of the position observer, even when operated at different speeds. Furthermore, a predictive controller was designed to enhance performance. A digital-signal processor (DSP), TMS-320F-28335, was used as a computation tool. Several simulated results are provided and compared with the measured results. The measured results showed that the implemented predictive controller sensorless SynRM drive system could be adjusted from 30 to 1800 rpm with satisfactory performance, including quicker and better tracking responses, and a lower speed drop than that of a proportional-integral (PI) controller.

Design and implementation of a passivity-based controller for sensorless synchronous reluctance motor drive systems

This study proposes a passivity-based controller for sensorless synchronous reluctance motor drive systems. By using the proposed controller, the drive systems can achieve fast transient responses, good load disturbance responses and good tracking responses. The parameters of the controller can be derived according to the required specification of the drive systems. In addition, a new sensorless technique based on an extended flux estimator is proposed as well. The estimator provides good performance in transient and steady-state conditions. The details are discussed. A digital signal processor TMS-320F-28335 is used to execute the rotor position/speed estimation, the passivity-based control algorithm, the d–q to a–b–c coordinate transformation, and the pulse width modulation switching strategy. As a result, the hardware is very simple. Experimental results show that the proposed system can perform in a wide adjustable speed range from 1 to 2000 r/min and a precise position control with satisfactory performance.

Adaptive controller design for a synchronous reluctance motor drive system with direct torque control

The design and implementation of adaptive controllers for a sensorless synchronous reluctance drive system with direct torque control is proposed. Two adaptive control algorithms, which include adaptive backstepping control and model-reference adaptive control, are proposed to improve the performance of a sensorless direct torque control synchronous reluctance motor drive system. A digital signal processor, TMS320-C30, is used to execute the rotor position estimating technique and the adaptive control algorithms. The system shows good transient responses, good load disturbance responses and good tracking responses. Several experimental results validate the theoretical analysis. The advanced controller design for a sensorless synchronous reluctance motor drive with direct torque control is proposed.

Position Control of a Sensorless Synchronous Reluctance Motor

This paper presents a novel position control for a sensorless synchronous reluctance drive system. By measuring the three-phase currents of the motor, a rotor position estimator is achieved. Then, a velocity estimator is derived from the estimated rotor position by using a state estimating technique. The estimated velocity tracks the real velocity well. Next, a robust position controller is designed to improve the transient and load disturbance responses. By using the proposed estimating techniques and control algorithm, a high-performance sensorless synchronous reluctance drive is obtained. A digital signal processor, TMS-320-C30, is used to execute the estimating and control algorithms. No hardware circuit or external signal is added as compared with the traditional drive system with an encoder or resolver. To evaluate the performance of the position control system, a moving table is connected with the drive system. The drive system can precisely control the moving table. Experimental results show that the proposed system has good performance. Several experimental results validate the theoretical analysis.