Iterative sliding mode observer for sensorless control of five-phase permanent magnet synchronous motor

Abstract

Abstract. Due to the star connection of the windings, the impact of the third harmonic which does not exist in three-phase permanent magnet synchronous motor (PMSM) cannot be ignored in five-phase PMSM. So the conventional sensorless control methods for three-phase PMSM cannot be applied for five-phase PMSM directly. To achieve the sensorless control for five-phase PMSM, an iterative sliding mode observer (ISMO) is proposed with the consideration of the third harmonic impact. First, a sliding mode observer (SMO) is designed based on the fivephase PMSM model with the third harmonic to reduce the chattering and obtain the equivalent signal of the back electromotive force (EMF). Then, an adaptive back EMF observer is built to estimate the motor speed and rotor position, which eliminates the low-pass filter and phase compensation module and improves the estimation accuracy. Meanwhile, by iteratively using the SMO in one current sampling period to adjust the sliding mode gains, the sliding mode chattering and estimation errors of motor speed and rotor position are further reduced. Besides, the stability of the SMO and the adaptive back EMF observer are demonstrated in detail by Lyapunov stability criteria. Experiment results verify the effectiveness of the proposed observer for sensorless control of five-phase PMSM.Key words: five-phase PMSM, sensorless control, iterative sliding mode observer (ISMO), Lyapunov criteria, speed and position estimation. system to decoupled equations in rotating coordinate system and controlling the five-phase PMSM as DC motor [10]. For the electric drive system of five-phase PMSM, the conventional control strategy usually needs the information of rotor position and speed for closed-loop control by position sensor such as an optical encoder fixed on the motor shaft [11]. Unfortunately, the position sensor, which is sensitive to the vibration and temperature, restricts the application of five-phase PMSM in electric drive system operated in harsh environmental conditions, and reduces the reliability of the whole electric drive system [12,13].Nowadays, with the development of digital signal processor [14-16], the sensorless control technology has gained more attention in drive control system of three-phase PMSM. The sensorless control techniques are generally divided into two categories which are the high-frequency signal injection method by utilizing the salient effect of PMSM [17][18][19] and the observer estimation method based on all kinds of observers [20][21][22]. Unfortunately, the high-frequency signal injection method depends on the saliency of the motor. So the application of this method is usually limited to interior PMSM. Besides, the high-frequency injection signal will bring high-frequency noise and cause the performance degradation in electric drive system. And the observer estimation methods such as model reference adaptive method [23,24] and Kalman filtering method [25,26] are dependent on an accurate model of the PMSM to a certain extent. However, for the good robustness, ...

Sensorless Field-Oriented Control for Open-End Winding Five-Phase Induction Motor With Parameters Estimation

“…This error is close to zero during the steady state operation and with very small increase at the instants of load torque change. In fact, the estimation error is significantly decreased compared to the results presented in [3], [29] and [39]. Thus, the proposed MRAS-SM observer offers precise estimation and high dynamics response.…”

“…It is found that the rotational speed and the estimated one follow the reference speed even at lower speeds. The estimation error is reduced from 6% to 0.2% compared to the work presented in [17]- [20], [26], [29], [39], [43], [44] and [45] as shown in Fig. 20.…”

“…The dynamic model of the FPIM can be expressed in the stationary 11 frame, in terms of the stator current and stator flux as follows: The expressions of the electromagnetic torque of the FPIM can be written as: The SM observer helps to increase the MRAS robustness in the event of parameters variation and internal system noises. However, this observer suffers from the chattering phenomenon due to the use of the signum function [18], [29]- [31]. To eliminate the effect of such an undesirable phenomenon, the classical signum function is replaced in this paper by the next function:…”

A novel Sensorless Control Strategy Based on Sliding Mode Observer for Non-Sinusoidal Seven-phase PMSM

“…In the literature we can find several methods which propose the sensorless control of permanent magnet synchronous machines (PMSM) [2]. These methods are based mostly on the observers, such as Model Reference Adaptive System (MRAS) [3], Extended Kalman Filter (EKF) [4], Luenberger Observer (LO) [5] and Sliding Mode Observer (SMO) [6]. Among these methods, SMO will be chosen to achieve the sensorless control of the seven-phase PMSM due to its simple implementation compared to EKF, which requires an important computation time especially in the case of multiphase machines.…”

“…Among these methods, SMO will be chosen to achieve the sensorless control of the seven-phase PMSM due to its simple implementation compared to EKF, which requires an important computation time especially in the case of multiphase machines. Furthermore, in terms of robustness, the SMO presents a robust structure against the variations of machine parameters and noise compared to the MRAS and LO [6].…”