Sensorless Control Technique Research Articles

A Hardware-in-the-Loop Realization of Speed Sensorless Control of PMa-SynRM With Steady-State and Transient Performances Enhancement

This paper presents the design and implementation of a novel low-cost speed sensorless control technique for a permanent magnet assisted synchronous reluctance motor (PMa-SynRM). A robust adaptive speed (RAS) observer is designed for estimating the rotor speed and position, respectively. The RAS observer estimates the PMa-SynRM speed and position from the back electromotive force space-vector determination without voltage sensors by using the reference voltages issued from the current controllers instead of the actual ones. The novelty of the proposed RAS estimation technique is the adaptation of the feedback error of the actual values. Thus, the proposed observer structure promises a higher degree of robustness against PMa-SynRM parameter changes in the sensitivity analysis presented in this paper. The dynamic model and experimental realizations of the proposed control technique are introduced. A 6-kW PMa-SynRM drive test setup is constructed including a dSPACE 1104 board as the control heart of the proposed system. The hardware-in-the-loop Typhoon HIL 402 device is used to experimentally emulate the PMa-SynRM and the inverter connected to a dSPACE MicroLabBox. The proposed RAS observer robustness is evaluated using a HIL model and experimental results under different conditions. A comparative experimental analysis between the proposed RAS and Luenberger observers has been performed.

Sensorless Control of BLDC Motor using Flux Linkage Based Algorithm

The performance of Conventional sensorless back-emf detection techniques for BLDC Motor is poor at low speeds, since at zero and low speeds the magnitude of back-emf is very less. This causes failure of zero crossing instant detection. This paper presents a new Sensorless Control Technique for BLDC motor drive to estimate the rotor position accurately even at zero and low speeds. A new algorithm has been developed to estimate the rotor position based on the prediction of stator flux linkages. The main advantage of the proposed technique is that the flux linkages are independent of the speed. For starting of the motor an open loop starting method was adopted. By implementing this technique the Meta heuristic digital signal control systems like PWM/ADC, PLL are avoided in order to make motor control easy and economical. To verify the accuracy of the proposed technique it is compared with existing hall sensors controlled BLDC drive operation. The validity of proposed scheme is verified through Simulation.

Review of sensorless control techniques for PMSM drives

AbstractPermanent magnet synchronous motor (PMSM) drive systems have been increasingly applied in all kinds of high‐power AC drives because of their inherent advantages of good performance, rapid dynamic response, as well as high reliability and efficiency. Precise control of the system traditionally depends on the shaft encoder, but the presence of the encoder could result in increased cost and volume, reduced reliability, etc. Therefore, the development of sensorless control techniques is important to avoid the above issues by the elimination of the sensor. Based on the running process of the motor, sensorless control techniques can be classified into four categories: initial position detection methods (IPDMs), low‐speed control strategies, mid‐high‐speed control strategies, and full‐speed control strategies. The fundamental principles, their advantages and disadvantages, the control precision, and the application range of these strategies on surface and interior permanent magnet synchronous motors (SPMSMs, IPMSMs) are described in detail in this paper. Finally, the development trend of PMSM sensorless control technologies is discussed. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Robust Normalized Mixed-Norm Adaptive Control Scheme for PQ Improvement at PCC of a Remotely Located Wind–Solar PV-BES Microgrid

The energy poverty in rural areas is due to the intermittent power supply from the existing utility. The proposed remotely located wind–solar photovoltaic array and battery energy storage (BES) supported microgrid, intends to overcome the uncertainty of the renewable power generation by compensating power quality (PQ) disturbances at the point of common coupling (PCC). Robust normalized mixed norm (RNMN) adaptive algorithm filters the load current component to remove the harmonics pertaining due to nonlinear load currents and improves the voltage profile at PCC. It allows the connection of sensitive loads without affecting their life and applicability at PCC. RNMN algorithm provides enhanced convergence rate as well as it reduces the steady-state error effectively. BES controlled by a bidirectional dc–dc converter ensures power supply to the critical loads during scarce generation by renewables resources. Proportional resonant controller provides superior performance over conventional proportional integral controller while dealing with the sinusoidal signals. Rejection of dc offset with effective harmonics elimination is provided by the improved second-order generalized integrator phase-locked loop. The speed regulation of the synchronous generator driven by a wind turbine is achieved by a sensorless field-oriented control technique. The maximum power point of each renewable resource is attained by individual implementation of perturb and observe scheme. The power sustainability is provided to the limited reach microgrid while overcoming the issues of load curtailment and PQ. Test results obtained on a developed prototype demonstrate the applicability of the control algorithms promising solution in controlling the intermittency and fluctuations related complex issues faced by the remotely located microgrid.

A Modulation Technique for Sensorless Control of Switched Reluctance Motor

The switched reluctance motor (SRM) uniquely bears several merits with respect to other motor configurations. Especially, the construction of the rotor is simple in the sense that it neither contains copper not contains permanent magnets. Because of this construction, likelihood of rotor’s failure is less than the other motor configurations. This makes this motor more suitable for harsh environments. On the flip side, this motor cannot directly operate with AC or DC power source and needs electronic commutation. For commutation, the information on instantaneous orientation of the rotor is essential. Since inclusion of appropriate sensor adds to the cost and complexity of the system, sensor-less commutation of SRM gained interest among the researchers and has been studied extensively in literature. The techniques for sensorless control of SRM can be broadly classified into Active phase and Idle phase techniques. Idle phase techniques are generally believed to be not suitable for high speed operation beause of tail current in a phase, i.e., because of inductive nature of the phase, it takes time for flow of current to stop. This paper proposes a novel idle phase technique that is conducive for high speed operation of switched reluctance motor.

Development and testing of an efficient and cost-effective underwater propulsion system

Underwater vehicle propulsion performed by exploiting electrical motor is in general the most flexible solution and it is growing in popularity because of its high efficiency both at high and at low advance speed, quick and simple deployment, low costs, and encumbrance. In the present work, permanent magnet synchronous motors for underwater propulsion are proposed. In particular, advanced sensorless control techniques of permanent magnet synchronous motors permit reduced costs, high reliability, and performances. When dealing with small autonomous underwater vehicle propulsion, such devices are hard to find in the market. Hence, the authors focused the research in the development of a system able to perform a reliable rotational speed and torque sensorless estimation. The design and implementation of a complete solution for underwater propulsion are presented as well as a novel rotor polarity identification technique exploiting a high-frequency injection control. Pool tests for the identification of the performances and of the dynamic parameters of the propulsion system are presented. Finally, the possibility of operating a sensorless estimation of the thrust and torque exerted by the propeller and pool test measurements are presented. These features could be exploited to improve navigation accuracy and involves obvious benefits in terms of cost reduction and reliability of the system.

Sensorless Control for Permanent Magnet Synchronous Motor in Rail Transit Application Using Segmented Synchronous Modulation

This paper proposes a position sensorless control technique for permanent magnet synchronous motor (PMSM) used in rail transit application, where a segmented synchronous modulation (SSM) is usually applied. The arbitrary signal injection-based sensorless control is adopted to estimate rotor position. In a switching period, an oversampling technique is used to obtain the average current slope that contains the rotor position information during the active voltage-vector operation. In SSM, the hysteresis zone is set near the carrier ratio (CR) switching critical point to eliminate the influence of the repeated oscillation on the current measurement accuracy. Furthermore, a load disturbance compensation method is designed so that the failure of hysteresis zone is avoided. Through the analysis of power spectral density (PSD) of phase current, the optimization of harmonic energy distribution with hysteresis zone is also verified. The experimental results show that the proposed method can improve the position estimation precision during the fast CR transition, which can be effectively applied in SSM.

A Modified Sensorless Control Scheme for Interior Permanent Magnet Synchronous Motor Over Zero to Rated Speed Range Using Current Derivative Measurements

This paper proposes a modified sensorless control technique for an interior permanent magnet synchronous motor over its full-speed range based on current derivative measurements and fundamental pulsewidth modulation excitation (FPE). The proposed method employs measurement of the current derivative at only one active-voltage vector at low speeds, and at one active-voltage vector and one zero-voltage vector at medium and high speeds during each pulsewidth modulation (PWM) cycle, in contrast to two active- and two zero-voltage vectors in the conventional FPE method. The theoretical analysis is developed based on the three-phase model of the machine. The rotor position and speed are estimated at PWM frequency. In addition, the selection voltage vectors for current derivative measurement as well as the pulse stretching scheme for extending and compensating the selected voltage vectors is proposed in order to improve the accuracy of the current derivative measurement and to minimize the current distortion. The experimental results show that the proposed method results in a considerable improvement of the estimation accuracy at low speeds, a significant reduction of current distortion compared to the conventional FPE method and a full-speed range operation from no load to full load.

A Comprehensive Review of Field-Oriented Control in Sensorless Control Techniques for Electric Vehicle

This paper is written to give a complete comprehensive analysis on sensorless Field-Oriented Control (FOC) in electric vehicle motor application. Sensorless control has opened a wide discussion in terms of its low cost and less complexity for crucial applications such as in electric vehicle, where rotor speed can be estimated by measuring the quantities of stator voltage and current at the terminal of the motor. Therefore, this paper provides a comprehensive review of the control methods for sensorless motor in order to increase motor efficiency. This review is based on vector control, which is the main focus in this paper, and on how it can be used more effectively in a wide speed range. Several tabulated tables are presented in order to give a fair comparison in determining the advantages of sensorless application of FOC in the estimation method for flux and speed controls. These tables show the effectiveness of each vector control in order to achieve the FOC. Lastly, the authors estimate the error, torque ripple and efficiency of the motor in order to allow readers to choose a suitable sensorless control for an effective method to increase the efficiency of an electric vehicle.

Robust Position Sensorless Technique for a PMBLDC Motor

The main objective of this paper is to present a new mechanical sensorless control technique of a permanent magnet brushless dc (PMBLDC) motor, which relies on the speed independent H functions. Two major challenges in the sensorless operation of PMBLDC motor drive are the starting the motor and driving it from a low speed to the rated speed. A speed independent H function is used to decide the commutation instant. Due to speed independence, the commutation instant is predicted even at low speed. The H function depends only on line voltages, which makes the overall system simple and cost effective. The proposed technique does not require any analog filter circuit or any phase compensation circuit. To eliminate the commutation ripple from the line voltages, digital low-pass filters and digital phase compensators are used. This makes the system compact, simple, and cost effective. This cost-effective solution proves perfect for low-cost appliances such as fan, air-conditioner, refrigerator, vacuum cleaner, and other home appliances. The proposed algorithm is implemented on a low-cost DSP (TMS320F28377S) to justify the effectiveness of the proposed sensorless technique for wide speed variation.

Analysis and experimental investigation into a finite time current observer based adaptive backstepping control of buck converters

In this paper, the issue of output voltage regulation in buck type dc-dc converters is addressed using a current sensorless control technique. The proposed strategy integrates a finite time current observer with an adaptive backstepping control scheme to yield a cost-effective and robust control mechanism. The overall controller stability in the sense of Lyapunov is proved. Applicability of the proposed control is verified experimentally on a buck converter in the laboratory. The control scheme is implemented on dSPACE DS1103 platform based on DSP TM320F240 processor. To examine the efficacy of the proposed method, the buck converter is subjected to a wide change in input voltage, load resistance and reference voltage. For comparison purpose, a conventional adaptive backstepping control scheme is evaluated under identical conditions of experimental study to examine the merit of the proposed control. The results obtained reveal that the proposed control is prompt in rejecting perturbations and achieves a smooth, reliable and satisfactory output voltage regulation with faithful and time bound estimation of inductor current. Thereby, this investigation demonstrates the validity of the proposed control in maintaining a stringent output voltage regulation in buck converters.

Design and Implementation of Sensorless Voltage Control of Front-End Rectifier for Power Quality Improvement in Telecom System

In this paper, a three-phase three-switch three-level boost (Vienna) type pulse-width modulation rectifier is proposed as an active front-end power factor correction (PFC) rectifier for power quality improvement in telecom load. A sensorless voltage control technique is proposed and it does not rely on any input voltage information results in reliable and robust operation. A brief description on the principle of operation and the most advantageous modulation method of the proposed system are discussed. The feasible switching states are identified for the proposed active front-end converter resulting in reduced switching stress and dc ripples. A triangular carrier based control logic is applied and the input current reaches sinusoidal shape without the need of sensing the input voltage. The detailed analysis of front-end PFC converter is carried out by equivalent circuit analysis. Also, the complete loss and efficiency calculation of the converter is explicitly carried out with the help of hardware design guidelines. The performance of the proposed system and its capability of operating satisfactorily in the event of failure of one phase of the mains is verified through MATLAB Simulation, and the results obtained are presented. The experimental setup rated for 9 kW is developed in the laboratory to validate the simulation results. From the simulation and hardware results, it is observed and recorded that the power quality parameters are improved and are well within the IEEE and IEC standards.

Sensorless Direct Torque Control of Surface-Mounted Permanent Magnet Synchronous Motors with Nonlinear Kalman Filtering

The demand for sensorless control of surface-mounted permanent magnet synchronous motor drives has grown rapidly. Among various sensorless control techniques developed, Matsui’s current model-based approach and the extended Kalman filter approach have gained much attention. However, the performance of these control methods can be severely worsened or may even become unstable under strong disturbances or sensing failures. This paper presents a comparative study of the extended Kalman filter, the resilient extended Kalman filter, and the unscented Kalman filter-based sensorless direct torque and flux control approaches for the surface-mounted permanent magnet synchronous motor drives. Computer simulation studies and hardware implementation results have shown the efficiency and superior performance of the resilient extended Kalman filter and the unscented Kalman filter over the traditional extended Kalman filter for sensorless direct torque control applications.

High-Frequency Voltage Injection Sensorless Control Technique for IPMSMs Fed by a Three-Phase Four-Switch Inverter With a Single Current Sensor

This paper proposes a sensorless control strategy using sine-wave high-frequency (HF) voltage injection for interior permanent magnet synchronous motors (IPMSMs) fed by a three-phase four-switch (TPFS) inverter, with a single current sensor. Three-phase currents are reconstructed by a single current sensor with modification of the inverter topology. The principle of the phase current reconstruction strategy in TPFS inverter is analyzed and the topology of the proposed drive system is illustrated. Then, the normal areas and the dead zones for current reconstruction are investigated in detail, and the vector synthesis method is also explained. Furthermore, the zero vector synthesis strategy and the pulse width modulation (PWM) generation method are also presented, where two current sampling points are applied in each PWM cycle for phase current reconstruction. Finally, an HF voltage injection based sensorless control strategy in the proposed drive system is realized by voltage projection on the proposed k – l axis coordinate system. The reconstructed phase currents track the actual ones accurately, and the estimation error of the rotor position by using the reconstructed phase currents is within ±0.1 rad. The effectiveness of the proposed scheme is verified by simulation and experimental results on a 5-kW IPMSM prototype.

Effective model predictive instantaneous power control for a sensorless induction motor drive

This paper presents an effective sensorless model predictive instantaneous power control (MP IPC) technique for an induction motor (IM) drive. The proposed control method is considered as an alternative control approach for classic field-oriented control (FOC) and direct torque control (DTC) techniques, with merits of simple implementation and avoiding the usage of PI current controllers and pulse width modulation (PWM) for voltage control purposes. An effective sensorless approach for the purpose of speed and rotor position estimations is proposed, which utilises the predictive feature of the proposed MP IPC technique. Matlab simulation is firstly used to validate the effectiveness of the proposed control topology, and then a dSpace1104 prototyping control board is used to implement the approach experimentally. Obtained results confirm the feasibility of proposed control technique in achieving decoupled control of instantaneous active and reactive powers flow through the IM drive, which consequently accompanied with decoupled control of torque and flux.

Configurations and control of traction motors for electric vehicles: A review

In recent decades, worldwide global warming and reduction in petroleum resources have accelerated researcher’s attention to produce alternative sustainable and environmentally clean transportation systems. Electrification of vehicular technology is capable of curbing the environmental pollution problem in an efficient and effective way, due to high efficiency electric motors, development and advancement in the field of power electronic devices, digital signal processing and advanced control techniques. This article presents a comprehensive review on different configurations/ architecture of electric vehicles(EVs) and hybrid electric vehicles(HEVs), traction motors for electric propulsion system and high performance speed sensorless control of traction drive. The basic architecture key components of hybrid vehicle and different power train configurations with respect to applications and limitations are discussed. The integral part of electric propulsion system, traction motor classes for desired operational characteristics and limitations are summarized from a system perspective with the latest improvements. High performance traction motor control techniques are discussed with respect to automotive applications. Finally, speed sensorless control techniques research trends as well as an extensive review on rotor speed estimation techniques for robust and efficient sensorless traction drive control are highlighted. This article provides state of the art key global trends and tradeoff of various technologies with future trends and potential areas of research.

Sliding Mode and Neural Network Control of Sensorless PMSM Controlled System for Power Consumption and Performance Improvement

This paper deals with the design of sliding mode control and neural network compensation for a sensorless permanent magnet synchronous motor (PMSM) controlled system that is able to improve both power consumption and speed response performance. The position sensor of PMSM is unreliable in harsh environments. Therefore, the sensorless control technique is widely proposed in industry. A sliding mode observer can estimate the rotor angle and has the robustness to load disturbance and parameter variations. However, the sliding mode observer is not conducive to standstill and low speed conditions because the amplitude of the back EMF is almost zero. As a result, this paper combines an iterative sliding mode observer (ISMO) and neural networks (NNs) as an angle compensator to improve the above problems. A dsPIC30F6010A-based PMSM sensorless drive system is implemented to validate the proposed algorithm. The simulation and experimental results prove its effectiveness.

Development of a Stator-Magnetless Linear Synchronous Motor for Sensorless Control

Sensorless control techniques that do not use a linear scale are desired for applications that require a long-stroke linear synchronous motor (LSM). This paper discusses the development of a stator-magnetless LSM (i.e., no magnet is mounted on the stator of the LSM) for sensorless control that includes a high-speed position estimation algorithm based on the magnetic hysteresis phenomenon. This paper presents a new structure of a flux-switching LSM that achieves a high saliency ratio using a cutout that results in magnetic saturation in the armature core. The effect of the sub-tooth on reducing the cogging thrust is also discussed. Furthermore, the analytical and experimental characteristics of inductance, thrust, cogging thrust, and sensorless drive control are discussed based on a prototype.

Saliency-based position sensorless control methods for PMSM drives - A review

Permanent magnet synchronous motor (PMSM) drives are finding expanded use for industrial and domestic drive applications. With the distinguished characteristics such as reduced cost and increased reliability and robustness, position sensorless (self-sensing) control techniques have been good candidates for reliable and costless PMSM drives. The saliency-tracking based techniques further bring the expansion of applications with the extended controllable sensorless operating speed range. This paper presents a review on state of the art techniques for position sensorless drives using the saliency-tracking based methods. The signal injection methods and the future scope of research including the dynamic bandwidth improvement and the acoustic noise reduction are discussed.

Sensorless control of switched reluctance drive with small DC-link capacitor for high-speed blowers

This paper presents a design concept of a sensorless control for high-speed SRM drives with small DC-link capacitor. In a cost-sensitive application, the expensive large DC-link capacitor should be replaced with a smaller DC-link capacitor for cost reduction. Using a small DC-link capacitor, the DC-link voltage extremely fluctuates during operation. The fluctuating DC-link voltage deteriorates the control stability and performance of the sensorless control. In the literature, the previous work has shown that the workable speed range of the existing sensorless control concept for high speed has been degraded to a smaller range when operating with fluctuating DC-link voltage. The proposed design concept deals with the challenge of improving the control stability of the sensorless control to operate in a wider operating speed range up to 75% (8000–35,000 rpm) under the fluctuating DC-link voltage. The control scheme is developed based on two basis sensorless control techniques, inactive phase method and current gradient method for covering the entire speed range. The proposed solutions work based on the appropriate selection of the detected signals according to the state of DC-link voltage. At the end, the functionality of the proposed technique is validated by experimental results.