Sliding Mode Observer Method Research Articles

Design and real-time implementation of a sliding mode observer utilizing voltage signal injection and PLL for sensorless control of IPMSMs

In this study, a sliding mode observer (SMO) based on high-frequency (HF) voltage signal injection and a phase-locked loop (PLL) is proposed for estimating the extended electromotive force (EEMF), rotor position, and rotor velocity of an interior permanent magnet synchronous machine (IPMSM). This approach addresses real-time estimation challenges associated with standard SMO and PLL at very low speeds and standstill. A reliable and accurate sensorless speed control system for IPMSM is then developed and implemented in real time using the proposed SMO and PLL, covering a wide range of speeds, including low-speed and standstill conditions. The SMO effectively estimates the EEMF, while the PLL extracts the rotor velocity and position based on these estimates. Compared to conventional SMO and PLL methods, real-time results from an 8-pole, 0.4 kW IPMSM demonstrate the superior efficiency of the proposed system.

Sensorless Control of Surface-Mount Permanent-Magnet Synchronous Motors Based on an Adaptive Super-Twisting Sliding Mode Observer

The Sliding Mode Observer (SMO) is widely used for the sensorless control of Permanent-Magnet Synchronous Motors (PMSMs) due to its simple structure and strong parameter robustness. However, traditional SMOs have a limited speed range and suffer from chattering issues, which affect the accuracy of rotor position estimation. To address these problems, this paper proposes an Adaptive Super-Twisting SMO (AST-SMO) method. First, a fast super-twisting function is designed to resolve the step problem that occurs at the zero-crossing of the traditional sign function. Next, an adaptive-tracking high-order Sliding Mode Observer is constructed to extend the speed range of the SMO. The stability of the system is proven using the Lyapunov theorem. Finally, a sensorless control system for PMSMs is implemented and validated in MATLAB/SIMULINK. The results indicate that, compared to the traditional SMO, the AST-SMO reduces the back EMF THD from 20.03% to 14.2%. Additionally, the rotor estimation error across all speed ranges is less than 0.01. Therefore, AST-SMO offers a higher tracking accuracy, a wider speed range, and effectively suppresses sliding mode chattering and harmonic interference.

Research on three-level PWM Rectifier without grid voltage sensor

Traditional three-level PWM rectification technology usually uses voltage sensors to sample the grid voltage, and then obtains the angle information of the voltage vector through a phase-locked loop, thereby achieving the d/q axis control function of voltage and current. However, the use of voltage sensors not only increases system costs, but also increases system volume and debugging difficulty. In addition, when the voltage sensor is damaged, it can cause system shutdown and affect system reliability. After analyzing the three-level control method of PWM rectifiers, a sensorless control strategy for grid voltage based on sliding mode observer method is proposed. By using the sliding mode observer method to estimate the amplitude and phase of the power grid voltage at the voltage and current values of each PWM cycle, a phase-locked loop is used to determine the position of its voltage vector. The simulation results all demonstrate that the proposed method can accurately and effectively estimate the voltage vector angle of the power grid, and ensure that the output of the rectification system meets the standard voltage waveform.

Multi-dimensional vector control for six-phase interior permanent magnet synchronous motor sensorless drive system

In order to realize high-performance control of six-phase interior permanent magnet synchronous motor (IPMSM), a multi-dimensional sensorless vector control scheme is discussed in this paper. Firstly, a new adaptive sliding mode observer (SMO) is designed to estimate the speed and rotor position information online, avoiding the phase delay caused by the traditional SMO method using the low-pass filter, and the detailed design method of observer parameters is given. In addition, the designed multi-dimensional vector control strategy fully exploits the advantages of multi-degree of freedom control for multi-phase motor drive system, considers the influence of x-y harmonic subspace, and sets the reference value of the current loop in harmonic subspace to zero to solve the stator current unbalance problem. Finally, the simulation model of the proposed control algorithm is built based on Matlab/Simulink simulation software, and the simulation results verify that the employed control technology has good control quality.

Wide-Speed-Range Sensorless Control of IPMSM

A wide-speed-range sensorless control for an IPMSM is deeply studied in this paper, which combines the high-frequency injection (HFI) method and sliding-mode observer (SMO) method. At low-speed range, a rotating high-frequency voltage signal is injected into the IPMSM; the rotor position can be estimated by the HFI method based on the saliency of the IPMSM. At high-speed range, an SMO method based on the extended back electromotive force (EMF) of the IPMSM is utilized to estimate the rotor position. Furthermore, to blend the positions estimated by these two methods, a speed-dependent weight function is designed. The steady-state and dynamic performance of the wide-speed sensorless control are investigated by experiments. In high-speed range, the position estimation errors of the SMO method at different operation points are smaller than 6 el.deg.; in low-speed range, the position estimation errors of the HFI method at different operation points are smaller than 15 el.deg.; and during the transition process, the IPMSM can switch smoothly between the HFI-based and SMO-based sensorless control methods.

On sliding mode observers for non-infinitely observable descriptor systems

This paper presents a sliding mode observer (SMO) design method to estimate the states and unknown inputs (UIs) in a class of non-infinitely observable (NIO) descriptor systems that contain UIs in both the state and output equations. Existing works on SMO design for NIO systems did not consider UIs in the output equation. In order to overcome the difficulty caused by UIs in output channels and the NIO condition, we reformulated the original system and introduced new UIs to replace the original UIs to obtain an equivalent infinitely observable descriptor system whose output does not contain any UI. Based on the developed equivalent system, a new SMO method is proposed to estimate both the states and the UIs. Subsequently, the necessary and sufficient conditions for the existence of the SMO are derived in terms of the original system matrices, which thus makes the conditions easy to be examined. Finally, an example is used to verify the effectiveness of the proposed method.

Sensorless Control of Permanent Magnet Synchronous Motor in Full Speed Range

Aiming at resolving the limitation of the speed regulation range of sensorless control technology, a new composite sensorless control strategy is proposed to realize a control method for a permanent magnet synchronous motor (PMSM) in full speed range. In the medium- and high-speed range, the improved new sliding mode observer method is used to estimate the motor speed and rotor position information. In the zero and low speed range, in order to avoid the defects of the sliding mode method, the rotating high-frequency voltage signal injection method is used. When switching between low, medium, and high speed, the fuzzy control algorithm is adopted to achieve smooth transitions. The simulation experiment results show that the hybrid mode combining the sliding mode observer and rotating high-frequency voltage injection methods, can effectively reduce the jitter in the algorithm switching process, and realize the smooth control of a PMSM in full speed range.

Sensorless DPCC of PMLSM Using SOGI-PLL-Based High-Order SMO With Cogging Force Feedforward Compensation

In order to reduce the adverse effect of the large thrust ripple of permanent magnet linear synchronous motor (PMLSM) on mover position estimation accuracy and solve the sliding mode chattering problem of the traditional sensorless algorithm based on sliding mode observer (SMO), this article proposes a systematic method to solve above issues. First, the high-order SMO method is used to suppress harmonic generation from the source of sliding mode chattering. Second, an adaptive filter based on a second-order generalized integrator (SOGI) is constructed to filter out the harmonics. Then, the normalized quadrature phase-locked loop (PLL) method is used to realize the closed-loop extraction of position information. Finally, the deadbeat predictive current control (DPCC) with the current feedforward compensation strategy is proposed to further improve the dynamic performance and mover position estimation accuracy. The simulation model and experimental platform are built. The simulation analyses and test results show that the proposed method has a better performance than conventional techniques.

Adaptive Fuzzy Fault-Tolerant Control against Time-Varying Faults via a New Sliding Mode Observer Method

In this study, the problem of observer-based adaptive sliding mode control is discussed for nonlinear systems with sensor and actuator faults. The time-varying actuator degradation factor and external disturbance are considered in the system simultaneously. In this study, the original system is described as a new normal system by combining the state vector, sensor faults, and external disturbance into a new state vector. For the augmented system, a new sliding mode observer is designed, where a discontinuous term is introduced such that the effects of sensor and actuator faults and external disturbance will be eliminated. In addition, based on a tricky design of the observer, the time-varying actuator degradation factor term is developed in the error system. On the basis of the state estimation, an integral-type adaptive fuzzy sliding mode controller is constructed to ensure the stability of the closed-loop system. Finally, the effectiveness of the proposed control methods can be illustrated with a numerical example.

Study on six‐phase PMSM control strategy based on improved position sensorless detection technology

The six-phase motor control system has low torque ripple, low harmonic content, and high reliability; therefore, it is suitable for electric vehicles, aerospace and other applications requiring high power output and reliability. This study presents a superior sensorless control system for a six-phase permanent magnet synchronous motor (PMSM). The mathematical model of PMSM in stationary coordinate system is presented; its sliding mode observer (SMO) of back electromotive force (BEMF) acquires the motor speed and position information. As torque ripple and harmonic components affect the BEMF estimated value through the traditional SMO, the function of the frequency-variable tracker of the stator current (FVTSC) is used instead of the traditional switching function. By improving the SMO method, the BEMF is estimated independently, and its precision is maintained under startup or variable-speed states. To improve performance of the system, the auto disturbance rejection controller (ADRC) is used to suppress load disturbance and speed overshoot. To reduce model parameters, an ADRC with sliding mode algorithm is proposed, simplifying the structure and simultaneously solving the parameter tuning problem. Finally, comparing the ADRC with FVTSC SMO and the traditional PI controller shows that the new ADRC effectively improves the dynamic and static performance of the PMSM.

Research on an Improved Sliding Mode Sensorless Six-Phase PMSM Control Strategy Based on ESO

The six-phase motor control system has low torque ripple, low harmonic content, and high reliability; therefore, it is suitable for electric vehicles, aerospace, and other applications requiring high power output and reliability. This study presents a superior sensorless control system for a six-phase permanent magnet synchronous motor (PMSM). The mathematical model of a PMSM in a stationary coordinate system is presented. The information of motor speed and position is obtained by using a sliding mode observer (SMO). As torque ripple and harmonic components affect the back electromotive force (BEMF) estimated value through the traditional SMO, the function of the frequency-variable tracker of the stator current (FVTSC) is used instead of the traditional switching function. By improving the SMO method, the BEMF is estimated independently, and its precision is maintained under startup or variable-speed states. In order to improve the estimation accuracy and resistance ability of the observer, the rotor position error was taken as the disturbance term, and the third-order extended state observer (ESO) was constructed to estimate the rotational speed and rotor position through the motor mechanical motion equation. Finally, the effectiveness of the method is verified by simulation and experiment results. The proposed control strategy can effectively improve the dynamic and static performance of PMSM.

Fault-Tolerant Quantized Sliding Mode Observers Design for a Class of Takagi-Sugeno Fuzzy System With Unmeasurable Premise Variable

This article addresses the state and fault estimation problems for a class of quantized Takagi–Sugeno (T-S) fuzzy systems with sensor and actuator faults. Two types of observer design methods are developed for two different network transmission environments. In the first case, the signal quantization effect is only considered on the channel between sensor and controller, and a sliding mode observer is designed, which can reconstruct the actuator faults. In the second case, the quantization effects are considered in both the sensor-controller side and the controller-actuator side, which is more difficult to be dealt with compared to the first case, and the sliding mode observer method cannot be effective now since the discontinuous term is difficult to be designed. A descriptor reduced-order observer is presented to solve this problem, where the jumping behavior that resulted from the signal quantization is considered in the observer, which is novel and effective to compensate the quantization effects. Finally, simulation examples of rigid-body satellite attitude control T-S fuzzy system are presented to verify the effectiveness of the proposed observer design approaches.

Research on Model Predictive Control Based on Sensorless Permanent Magnet Synchronous Motor

For permanent magnet synchronous motor (PMSM) speed control system, aiming at the problems of slow dynamic response and large dependence on system model parameters of traditional PI control of PMSM, the model predictive current control strategy is adopted to design the predictive model. Aiming at the problems of poor reliability and high cost of traditional permanent magnet synchronous motor with mechanical sensor, the speed sensorless control technology is introduced to design the control structure, and the rotor position and speed are estimated by sliding mode observer method. Through simulation verification, the results show that the combination of the above two control methods can obviously improve the performance of the traditional permanent magnet synchronous motor control system, and has strong robustness under the conditions of motor parameters and load changes.

Full-Order Sliding Mode Observer Based on Synchronous Frequency Tracking Filter for High-Speed Interior PMSM Sensorless Drives

In the research of the high-speed sensorless control strategy of an interior permanent-magnet synchronous motor (IPMSM), considering the harmonic influence of inverter nonlinearity on traditional sliding mode observer method, a full-order sliding mode observer (SMO) method based on synchronous frequency tracking filtering is proposed. This method avoids the phase delay defects caused by the use of filters in traditional second-order SMO. Then, the observed extended electromotive force (EMF) signal is filtered using a synchronous frequency tracking (SFT) function. It tracks the changing stator current and filters out harmonics that are not part of the tracking signal to achieve static tracking of the stator current. Then, the rotor speed can be estimated by a Luenberger-based observer. Experimental results verify the effectiveness and feasibility of the proposed method.

Research on Sensorless Control of Permanent Magnet Synchronous Motor

For the information of the rotor position of the permanent magnet synchronous motor position sensorless control system, the calculation method of different rotor positions of the motor under high speed and low speed is proposed. In the low speed state, the rotor information cannot be extracted because the back electromotive force on the stator is too small. The rotor position information can be obtained by the high-frequency voltage injection method. When the motor is in the medium-high speed operation state, the sliding mode observer method is introduced, and the rotor position information of the motor can be estimated. Finally, the rotor speed estimated by the sliding mode observer is obtained by simulation. The accuracy of the rotor position.

Reduced-Order Sliding-Mode-Observer-Based Fault Estimation for Markov Jump Systems

This paper is concerned with the fault and state estimation problem for Markovian jump systems (MJSs) with simultaneous actuator and sensor faults. To deal with the design issues, we propose a novel descriptor reduced-order sliding mode observer (SMO), based on which the estimation of the actuator faults, sensor faults, and the states can be obtained simultaneously. Compared with the traditional SMO design issues in MJSs, we reconstruct the actuator faults directly without employing the equivalent output error injection method. Thus, the reachability analysis of the sliding surface is not necessary. The superiority of this kind of the SMO method is that the sliding surface switching problem is avoided. Finally, the effectiveness (as suggested by the theoretical results) of the approach described is tested on a mobile manipulator by simulation studies.

Actuator and Sensor Fault Estimation for Time-Delay Markov Jump Systems With Application to Wheeled Mobile Manipulators

In this paper, fault and state estimation issue for wheeled mobile manipulators with time delay, using a novel sliding mode observer (SMO) approach has been discussed. It is well-known that the traditional SMO method, i.e., the equivalent output error injection technique cannot be simply employed to Markov jump systems (MJSs) to estimate actuator faults. In this paper, we propose a novel SMO to reconstruct the actuator and sensor faults for MJSs with time delay. First, we decouple the actuator faults from the first subsystem by utilizing coordinate transformation technique. Then, construct an augmented plant for the new system and propose a novel reduced-order SMO. By the proposed novel SMO, the state and fault can be reconstructed simultaneously. Finally, an illustrative wheeled mobile manipulator example is given to show the effectiveness of the proposed approach.

An improved synchronous reference frame filter for sliding mode observer position sensorless method of open‐winding pm generator system

AbstractIn view of the relatively low estimation accuracy in the low‐pass filter (LPF)‐based sliding mode observer (SMO) method, synchronous reference frame filter (SRFF)‐based SMO (without input LPF) method, and SRFF‐based SMO (with input LPF) method, an improved SRFF‐based SMO position sensorless method of the open‐winding permanent magnet generator (OWPMG) system is presented. This improved SRFF consists of a programmable eighth‐order low‐pass filter (8th‐PLPF), a traditional SRFF, and two phase‐locked loops (PLL1 and PLL2). Based on the synchronous angular frequency obtained by PLL2, the 8th‐PLPF together with the traditional SRFF can not only effectively filter out the harmonics in the output of the SMO but also achieve the fundamental back‐EMF without magnitude and phase angle errors. Then, based on the obtained accurate back‐EMF, the estimated rotor position angle can be obtained without phase shift. The OWPMG system using the improved method can work well in both steady‐state and dynamic conditions, which is verified by experimental results. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Satellites Autonomous Navigation With an Extended State and Disturbance Sliding Mode Observer Method

This paper considers the satellites autonomous navigation problem with an extended sliding mode observer method. First, on consideration that the relative dynamic equation of chaser and target spacecrafts refers to a nonlinear time-varying system, a transformation is performed on the original relative dynamic equation to obtain a linear time-invariant system with a nonlinear part. Second, an augmentation strategy is made on the new system to obtain a descriptor system. A new extended sliding mode observer is then designed for the descriptor system which can generate the simultaneous estimation of state and output measurement noise. Based on the observer estimates, the equivalent output error injection approach is used to estimate the space disturbance moment. Finally, an example is presented to demonstrate the effectiveness of the developed satellites autonomous navigation observer method.

Stabilization computation for a kind of uncertain switched systems using non-fragile sliding mode observer method

A non-fragile sliding mode control problem will be investigated in this article. The problem focuses on a kind of uncertain switched singular time-delay systems in which the state is not available. First, according to the designed non-fragile observer, we will construct an integral-type sliding surface, in which the estimated unmeasured state is used. Second, we synthesize a sliding mode controller. The reachability of the specified sliding surface could be proved by this sliding mode controller in a finite time. Moreover, linear matrix inequality conditions will be developed to check the exponential admissibility of the sliding mode dynamics. After that, the gain matrices designed will be given along with it. Finally, some numerical result will be provided, and the result can be used to prove the effectiveness of the method.