Robust Sensorless Control Research Articles

Adaptive Robust Sensorless Control for PMSM Based on Improved Back EMF Observer and Extended State Observer

Adaptive Robust Sensorless Control for PMSM Based on Improved Back EMF Observer and Extended State Observer

Robust Sensorless Control of Synchronous Reluctance Motor Based on PDSH-KF Considering Dynamic Magnetic Saturation Effect

Robust Sensorless Control of Synchronous Reluctance Motor Based on PDSH-KF Considering Dynamic Magnetic Saturation Effect

Multiparameter Estimation-Based Sensorless Adaptive Direct Voltage MTPA Control for IPMSM Using Fuzzy Logic MRAS

This paper introduces a parameter-estimation-based sensorless adaptive direct voltage maximum torque per ampere (MTPA) control strategy for interior permanent magnet synchronous machines (IPMSMs). In direct voltage control, the motor’s electrical parameters, speed, and rotor position are of great significance. Thus, any mismatch in these parameters or failure to acquire accurate speed or position information leads to a significant deviation in the MTPA trajectory, causing high current consumption and hence affecting the performance of the entire control system. In view of this problem, a fuzzy logic control-based cascaded model reference adaptive system (FLC-MRAS) is introduced to mitigate the effect of parameter variation on the tracking of the MTPA trajectory and to provide precise information about the rotor speed and position. The cascaded scheme consists of two parallel FLC-MRAS for speed and multiparameter estimation. The first MRAS is utilized to estimate motor speed and rotor position to achieve robust sensorless control. However, the speed estimator is highly dependent on time-varying motor parameters. Therefore, the second MRAS is designed to identify the quadratic inductance and permanent magnet flux and continuously update both the speed estimator and control scheme with the identified values to ensure accurate speed estimation and real-time MTPA trajectory tracking. Unlike conventional MRAS, which uses linear proportional-integral controllers (PI-MRAS), an FLC is adopted to replace the PI controllers, ensuring high estimation accuracy and enhancing the robustness of the control system against sudden changes in working conditions. The effectiveness of the proposed scheme is evaluated under different speed and torque conditions. Furthermore, a comparison against the conventional PI-MRAS is extensively investigated to highlight the superiority of the proposed scheme. The evaluation results and our quantitative assessment show the ability of the designed strategy to achieve high estimation accuracy, less oscillation, and a faster convergence rate under different working conditions. The quantitative assessment reveals that the FLC-MRAS can improve the estimation accuracy of speed, permanent magnet flux, and quadratic inductance by 19%, 55.8% and 44.55%, respectively.

Experimental implementation of low-cost and robust sensorless control based on SOGI-FLL estimator for electric vehicles

Sensorless control techniques of electric motor dedicated to electric vehicles (EVs) offer low-cost and high operating performance. In this paper, a low-cost and robust speed-sensorless control scheme based on a second-order generalized integrator-frequency-locked loop method (SOGI-FLL) is proposed with only one current sensor. The SOGI-FLL is introduced to estimate accurately the motor angular speed from a measured current signal. While the scalar control technique, based on a single loop speed regulation, is used to determine the <em>‎</em>control signals. According to the proposed control scheme, the overall system will be very effective in terms of low-cost control and easy practical implementation, which have a great impact on electric vehicle applications. dSPACE micro labox platform is used to implement the proposed control scheme to drive an induction motor. The obtained results confirm the effectiveness and high performance of the proposed control to properly estimate the angular speed and drive the induction motor.

Sensorless passivity based control of doubly-fed induction generators in variable-speed wind turbine systems based on high gain observer

The current study presents a robust sensorless control using passivity based control (PBC) combined with high gain observer (HGO). The proposed controller is applied to control the generated doubly-fed induction generator (DFIG) active and reactive power installed on a variable speed wind energy conversion system. The control objective is used to regulate independently the DFIG stator active and reactive power, which are decoupled by using the field oriented control technique. Additionally, this process leads to reduce the cost of control scheme by eliminating the speed sensor. Firstly, the DFIG is modeled under the port controlled Hamiltonian (PCH) model, as well as the method of simultaneous injection damping. Then, the DFIG is further modeled by assignment passivity based on the simultaneous injection damping and assignment (SIDA-PBC) control of the obtained model under such conditions and a comparison with the fuzzy sliding mode controller is carried out. Furthermore, the HGO is selected in order to estimate the rotor position and the speed from the measurement of the DFIG currents and voltages, and compared with fuzzy sliding mode observer. For testing the proposed control scheme performance, a 1.5 MW DFIG system is developed and simulated using MATLAB/Simulink. The obtained results demonstrate the effectiveness of the proposed control scheme in the presence of various DFIG parameters variation. Additionally, the control objective is achieved without speed sensor.

A Hybrid H∞-MRAS Observer of Wind Turbines Conversion Systems based on DFIG

This study proposes the robust sensor-less advanced frequency control (robust H∞ control) of the system of wind turbine based on a doubly fed induction generator (DFIG), the power exchange between the machine stator and the network is achieved by applying the rotor of DFIG via a bidirectional converter. The purpose of the control is to regulate the stator active and reactive power produced by the DFIG using a robust H∞ controller. The Model reference and adaptive system (MRAS-Observer) uses the error between the actual and estimated values ​​(voltage/current) to construct the observed mechanical parameters (speed and position) value, this technique uses two separate models: the first is the reference model, the second is the adjustable mode. The error between these models is used by the adaptive mechanism. The adjustment mechanism is mostly a PI controller, to improve the performance and robustness of the classical MRAS observer, we replace the classical PI controller with a robust H∞ controller. The results simulations confirm the robustness of the sensorless robust H∞ control using the H∞-MRAS observer compared to conventional MRAS, which improves the quality and quantity of generated power.

Advanced sliding mode speed observer with compensated stray‐load and iron losses for a stand‐alone wind turbine‐driven induction generator

AbstractModel‐based speed estimation schemes in sensorless field‐oriented control (FOC) of induction machines (IMs) are designed on the basis of a corresponding mathematical model. Thus, a reliable and robust sensorless controller requires using a more detailed IM model. The omission of nonlinear phenomena in real‐time application, such as magnetic saturation, iron losses, and stray‐load losses, certainly leads to inaccuracy in the estimated speed due to the existence of the mentioned phenomena in the IM. In this context, we address here the problem of neglecting the stray‐load and iron losses in a model‐based speed observer, synthesized by means of sliding mode theory, and we evaluate the impact of this omission on the execution of the utilized FOC and maximum power point tracking (MPPT) algorithm applied for a stand‐alone wind energy conversion system (WECS). The performance of the proposed sliding mode speed observer (SMSO), derived from the IM model including the above mentioned nonlinear phenomena, is experimentally evaluated over wide ranges of wind speed and IM magnetizing flux. It is also compared with the model reference adaptive system (MRAS) speed estimator, which is derived from the same IM model, as well as to the simplified SMSO, designed based on the IM model without stray‐load and iron losses. The obtained results show that the proposed SMSO has greater robustness with respect to abrupt variations of the rotor flux in comparison with the MRAS speed estimator, whereas it ensures significantly more stable operation and lower speed estimation error in comparison with the simplified SMSO.

High performance of sensorless sliding mode control of doubly fed induction motor associated with two multilevel inverters fed by VFDPC_SVM rectifier

A robust sensorless control based on the sliding-mode observer applied to a doubly fed induction motor associated with two three-level NPC-type voltage inverters fed by PWM rectifier with constant switching frequency and without line voltage sensors, is presented in this paper. Also, we present an improved direct power control with virtual flux (VFDPC_SVM) for the control of three phase rectifier. Simulation results of this proposed system were analyzed using MATLAB environment.

Robust Sensorless Control Against Thermally Degraded Speed Performance in an IM Drive Based Electric Vehicle

This article investigates and proposes an efficient control design to address the degradation in the mechanical speed of a traction machine drive (TMD) in an electric vehicle (EV) caused by thermal effects during its operation. Variations in the operating as well as ambient temperature cause unexpected uncertainties in TMD parameters such as stator and rotor resistances, which results in significant degradation in EV's speed performance capability. To mitigate this problem, an output feedback robust linear parameter varying (LPV) controller-observer set is designed using H <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_{\infty }$</tex-math></inline-formula> control theory that enhances the EV's speed performance in field-oriented control (FOC) frame. The internal stability of the closed-loop control and the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$L_{2}$</tex-math></inline-formula> gain bound are ensured by linear matrix inequalities. The performance of the proposed control technique is compared with that of conventional FOC, sliding mode control (SMC) and higher order sliding mode control (HOSMC) to validate its efficacy and advantages. The robustness of the proposed control technique is tested for an EV operation against the Worldwide Harmonised Light Vehicles Test Procedure (WLTP) Class 3 driving cycle. The nonlinear MATLAB simulation results guarantee the effectiveness of the proposed controller-observer set. These results are verified experimentally on an induction machine drive setup.

Extended Sliding Mode Disturbance Observer-Based Sensorless Control of IPMSM for Medium and High-Speed Range Considering Railway Application

The sliding mode observer (SMO)-based approach known for its robustness towards parameter variation (external disturbance) has been used for the sensorless motor drive system. Delay compensation is commonly added to overcome the phased delay resulted from the introduction of the low-pass filter for chattering suppression. In this paper, a new extended sliding mode disturbance observer (ESMDO)-based sensorless control of interior permanent magnet synchronous motor for the medium and high-speed range is presented. The effect of parameter variation and coordinate transformation is considered as a lumped disturbance, and ESMDO is designed to compensate for the imminent impact of such scenarios. A Lyapunov stability theory is adopted to guarantee the stability of the proposed ESMDO-based sensorless control method. The ESMDO has an inbuilt low-pass filter and does not introduce a phased delay. A very large load change/reference speed variation may result in system instability or require higher controller gains that lead to system chattering. Hence, a PI-based compensation is incorporated to achieve a smooth and robust sensorless control algorithm considering the d-axis disturbance. Finally, extensive simulation and hardware-in-the-loop (HIL) test using the TMS320F28335 control unit in a real-time environment are conducted to verify the effectiveness of the proposed sensorless control method.

A Simple and Robust Sensorless Control Based on Stator Current Vector for PMSG Wind Power Systems

This paper proposes a novel sensorless control based on the stator current vector for permanent-magnet synchronous generators in variable-speed wind energy conversion systems. In the proposed method, the rotor angle and speed are estimated indirectly from the stator currents, where only the stator inductance is required regardless of the stator resistance. In addition, the proposed method uses one current control loop to regulate the stator current magnitude, rather than two current control loops. To eliminate the current measurement noise, the second-order generalized integrator (SOGI) with a frequency-locked loop (FLL) is utilized, which can improve the estimation performance. The proposed sensorless control method with the SOGI-FLL is simple and easy to implement while achieving a fast and accurate estimation performance of the rotor angle and speed. The feasibility of the proposed method has been verified by simulation and experimental results.

An improved robust MPPT control for variable speed wind turbine without mechanical sensor: Exprimental evaluation

This paper presents a robust sensorless control scheme of permanent magnet synchronous generators (PMSG) wind turbine with two full-scale controllable three phase converter connected to the grid. The main aim is to drive wind turbine at an optimal rotor speed in order to perform maximum power point tracking (MPPT) control of the wind generation system. The proposed strategy combine a nonlinear backstepping control of the PMSG which is based on both feedback laws and Lyapunov theory, and a non-linear sliding mode observer(SMO) to estimate the PMSG rotor position and to perform a sensorless control. The PMSG wind turbine is integrated to the grid through a three phase inverter which is controlled with classical proportional integral (PI) to control the active and reactive power. The proposed method was successfully tested with both simulation and experimental setup using MATLAB and a dSPACE 1104 platform. The obtained simulation and experimental results show clearly the accuracy and the effectiveness of the proposed method.

Experimental design of a new fast sensorless control of DFIG in complex domain

In this study, a new robust sensorless control of doubly-fed induction generator (DFIG) in the complex domain has been investigated. The proposed sensorless control is based on the extended complex Kalman filter (ECKF) and proportional–integral complex controller. The design of this sensorless control in the complex domain allowed a threefold objective: a decrease in the system's dimension by half, an optimisation in the implementation of the control strategy and a decrease of the CPU computational time. In fact, to obtain the latter, the dimension of the DFIG model involved in this control has been halved, which leads to a reduction in the control's schema. Moreover, all the matrices involved in the ECKF have smaller dimensions than those of the real extended Kalman filter and no matrix inversion is needed because the output of the system is a scalar variable. The proposed sensorless control has been tested experimentally for several operating points, namely: nominal operation, operation under asymmetrical voltage dip and parameter variations. Moreover, the observability of the complex state model has been analysed and the required conditions for the local weak observability have been defined. The experimental results confirm the theoretical study and show a good reliability and a high rotor speed estimation accuracy.

An extended observer-based robust nonlinear speed sensorless controller for a PMSM

ABSTRACTThis work focuses on the problem of observer-based robust speed sensorless control of a 3-phase permanent magnet synchronous motor (PMSM). Nonlinear design techniques are employed for designing robust speed controller and observer that are able to withstand the effects of modelling uncertainties and load variations. A new cascaded observer scheme is proposed comprising a continuous sliding mode observer (SMO) and an extended high-gain observer (EHGO). The proposed cascaded observer reduces chattering, exhibits reasonable insensitivity to modelling inaccuracies and is capable of withstanding errors due to the finite boundary layer of continuous SMO. For the robust speed control, an integral sliding mode controller is designed that yields fast and accurate speed tracking performance even in the presence of bounded uncertainties and external disturbances. The complete scheme has been evaluated using simulations and experiments.

Multirate output feedback-based robust sensorless control of doubly-fed induction motor

A robust sensorless control of doubly-fed induction motor (DFIM) is proposed in this paper. The stator of the DFIM is connected to the grid and the rotor is fed via controlled voltage source. Since the speed or flux measurement is not used, the sensorless control is achieved by using multirate output feedback (MROF)-based output feedback technique. The robustness towards parametric variations and matched disturbances is achieved by using MROF-based sliding mode control (SMC). The linear equations of doubly-fed induction motor are utilised for application of MROF and the state reference commands are computed from torque and speed reference commands separately. The proposed MROF-SMC controller is shown to be tracking given torque and speed commands.

Multirate output feedback-based robust sensorless control of doubly-fed induction motor

Multirate output feedback-based robust sensorless control of doubly-fed induction motor

A Robust Sensorless Control of PMSM Based on Sliding Mode Observer and Model Reference Adaptive System

&lt;p&gt;This paper is intended to study and compare the operation of two methods for estimating the position/ speed of the permanent magnet synchronous motor (PMSM) under sliding mode control. The first method is a model reference adaptive system (MRAS). The second method based on sliding mode observer (SMO). The stability condition of Sliding Mode Observer was verified using the Lyapunov method to make sure that the observer is stable in converging to the sliding mode plane. In this paper the performances of the proposed two algorithms are analyzed using SIMULINK/MATLAB. The simulations results are presented to verify the proposed sensorless control algorithms and can resolve the problem of load disturbance effects by simulations which verify that the two closed-loop control system is robust with respect to torque disturbance rejection.&lt;/p&gt;

A unified observer for robust sensorless control of DC–DC converters

Due to the large variety of converters' configurations, many different sensorless controllers are available in the literature, each one suited for a particular converter. The need for different configurations, especially on the same power supply, make it clear the advantage of having a shared control algorithm. This paper presents a unified nonlinear robust current observer for buck, boost and buck–boost converters in synchronous and asynchronous configurations. The unified observer speeds up the design, tuning and the implementation, and requires a memory cheaper code, easier to certify. Simulation and experimental results are presented to validate the approach in different scenarios.

Robust hybrid sensorless control of variable speed wind turbine with permanent magnet synchronous generator

Robust hybrid sensorless control of variable speed wind turbine with permanent magnet synchronous generator

Experimental sensorless control for IPMSM by using integral backstepping strategy and adaptive high gain observer

In this paper a robust sensorless control for an Interior Permanent Magnet Synchronous Motor (IPMSM) is designed. The proposed control strategy uses a backstepping controller, whose robustness is improved by using integral actions added at each step of the original algorithm, and by a Maximum-Torque-Per-Ampere strategy (MTPA) to improve its energy efficient operation. Furthermore, to implement this controller in the framework of the mechanical sensorless control from the only measurements of the currents and voltages, an adaptive interconnected high gain observer is developed for estimating the rotor speed, the position and the load torque. Moreover, sufficient conditions are given to ensure the practical stability of the Observer-Controller system even if bounded uncertainties occur. Finally, the performance and the effectiveness of the designed method are tested experimentally throw a significant benchmark including different speed references and with significant robustness tests. A comparative evaluation of the computational effort of our scheme with respect to classical motor control is given.