Position Sensorless Control Research Articles

An Extended Sliding Mode Observer for Speed, Position and Torque Sensorless Control for PMSM Drive Based Stator Resistance Estimator

This paper presents a robust sixth-order Discrete-time Extended Sliding Mode Observer (DESMO) for sensorless control of PMSM in order to estimate the currents, speed, rotor position, load torque and stator resistance. The satisfying simulation results on Simulink/Matlab environment for a 1.6 kW PMSM demonstrate the good performance and stability of the proposed ESMO algorithm against parameter variation, modeling uncertainty, measurement and system noises.

Half step position sensorless control of a Linear Switched Reluctance Motor based on back EMF

This paper presents a position sensorless closed loop control of a switched reluctance linear motor. The aim of the proposed control is to damp the position of the studied motor. Indeed, the position oscillations can harm some applications requiring high position precision. Moreover, they can induce the linear switched reluctance motor to an erratic working. The proposed control solution is based on back Electromotive Forces which give information about the oscillatory behaviour of the studied motor and avoid the use of a cumbersome and expensive position linear sensor. The determination of the designed control law parameters was based on the singular perturbation theory. The efficiency of the proposed control solution was proven by simulations and experimental tests.

拡張誘起電圧と搬送波に同期した電圧重畳に基づくIPMSMの位置センサレス制御

This paper presents a new position sensorless control system for an interior permanent magnet synchronous motor (IPMSM). The proposed method is based on the extended electromotive force (EMF) and voltage injection synchronized with a pulse-width modulation (PWM) carrier. The proposed method does not need to switch the estimation method by speed in order to estimate the magnetic pole position by extended EMF, even at low speeds. Further, the amplitude of the superimposing voltage is changed according to the extended EMF; the applied voltage is not saturated in the high-load and high-speed regions. The effectiveness of the proposed sensorless control system was verified experimentally.

直接トルク制御を用いた高速モータドライブシステムの離散化誤差補償方法

SUMMARY In this paper, a discretization error compensation method in a motor drive system by using direct torque control (DTC) is proposed. Similar to a conventional current control system, DTC allows an efficient drive and a wide range drive. Furthermore, it has the advantage that its control system can be simple and theoretically it can realize sensorless position control. Therefore, a reference flux vector calculator (RFVC) DTC is studied as a system for the ultra-high-speed drive control of permanent magnet synchronous motors (PMSMs). In high-speed drive, we revealed that a discretization error in the DTC generates an error in the instruction magnetic flux and stator magnetic flux. In addition, we revealed that current detection timing generates an error in the estimated torque and real torque. Then, we propose a compensation method to cancel the flux and torque error focusing on the phase of the stator magnetic flux and experimentally verifying its effectiveness.

Walsh series modeling and estimation in sensorless position control of electrical drives

High-performance electrical drives can be achieved by usingeld-oriented controllers, which make torque and ux naturally decoupled. A conventional vector-controlle d drive has the disadvantage of either requiring ux and speed sensors or being affected by rotor resistance, which varies along with the motor performance. The presented paper focuses on developing a high-performance sensorless rotor ux-oriented controller of an induction machine independent of the rotor resistance variation. This method applies spectral theory of Walsh functions, which are one of the most helpful members of piecewise constant basis functions in solving dynamic models. Inherent characteristics of Walsh functions and application of an operational matrix will make the system handy and robust against inverter switching effects.

Position-Sensorless Control of <inline-formula> <tex-math notation="LaTeX">$\text{DC} + \text{AC}$</tex-math></inline-formula> Stator Fed Doubly Salient Electromagnetic Motor Covered Full Speed Range

The position-sensorless control methods of dc+ac stator fed doubly salient electromagnetic motor (DSFDSEM) covered full speed range are presented in this paper. To implement these methods, the following procedures are done. First, the series self-inductance area difference method, in consideration of cogging torque produced by field current, is adopted for identifying the initial position. Second, the current pulse injection technique in the commutation point is proposed to detect the commutation moment at low speed. Finally, the terminal voltages are considered as vectors with a fixed phase difference, and the composed vector is rotated with varying rotor positions; the commutation point can be obtained by coordinate transformation of three terminal voltages at high speed. The filter with a low cutoff frequency is not required in this method. Moreover, the smooth-switch technology between startup and high-speed operations is researched to prevent the out-of-step fault. The sensorless control of a DSFDSEM from startup at standstill to high-speed operation can be easily implemented by the aforementioned methods. No additional hardware or complex computation is required. A 12/8 DSFDSEM prototype is built and tested to verify the feasibility of the proposed sensorless schemes.

Position Sensorless Control of BLDC Motors Based on Global Fast Terminal Sliding Mode Observer

The brushless DC motor (BLDCM) has many advantages. As a result, it is widely used in electric vehicle (EV) drive systems. To improve the reliability of the motor control system, a position sensorless control strategy based on a sliding mode observer (SMO) is proposed. The global fast terminal sliding mode observer (GFTSMO) is proposed to enhance the control performance of the SMO control system. The advantages of the linear sliding mode and the nonsingular terminal sliding mode (NTSM) are combined in the control strategy. The convergence speed of the system state is enhanced. The motor commutation point is obtained with the observation of the back EMF, and the instantaneous torque value of the motor is calculated. Therefore, the position sensorless control of the BLDCM is realized. Experimental results show that the proposed control strategy can improve the convergence speed, dynamic characteristics and robustness of the system.

SENSORLESS POSITION CONTROL OF DC MOTOR USING MODEL PREDICTIVE CONTROLLER

Sensors like rotary encoders are widely used in measuring the speed and position of DC motor in applications. Due to expensiveness, calibration complexities of these type of encoders, sensorless methods for measurements were used alternatively. This paper presents sensorless position control of a wheeled DC motor using system identified model. This approach overcome some conventional sensorless techniques that uses some approximations. The model is developed using black box identification scheme, based on the identified model, a model predictive controller was designed to track a desired horizontal position of the wheel. Practical experiment shows the concept gives a very good estimation of the position and speed and can be used in control application.

Hybrid Active-Flux and Arbitrary Injection Position Sensorless Control of Reluctance Synchronous Machines

A new hybrid position sensorless control method for reluctance synchronous machine drives is presented in this paper. The active-flux (AF) and arbitrary injection position estimation techniques are combined for the first time in this hybrid controller. The controller switches between estimation techniques depending on speed and load. A hysteresis region is implemented with phase-locked loop synchronization for dynamic and stable changeovers between estimators. Implementation of the AF method at high loads allows for extended sensorless torque capabilities at high speed.

Position sensorless surface‐mounted permanent‐magnet synchronous generator and its application to power DC microgrid

This study presents a position sensorless surface-mounted permanent-magnet synchronous generator (SPMSG) and its application in powering DC microgrid. The derated characteristics of a PMSG with different AC–DC converters under brushless DC generator (BDCG) mode and the conventional switch-mode rectifier (SMR) mode are first comparatively assessed. Then a PMSG followed by three-phase three-switch Vienna SMR is established. Good operation performance is achieved via the proposed robust current and voltage control schemes. Second, a position sensorless control scheme based on observed extended back electromotive force (EMF) for the SPMSG followed by Vienna SMR is developed. The generation characteristics are enhanced by the developed starting and back-EMF angle tuning schemes. Third, a single-phase three-wire load inverter with the proposed novel robust waveform tracking control scheme is developed to yield good AC 220 V/110 V output voltage waveforms under unknown and non-linear loads. Some experimental results are provided to demonstrate the operation performances of the established SPMSG system in conventional generator with fixed output voltage and wind generator. More specifically, the BDCG mode and the SMR mode for operating a PMSG are experimentally evaluated.

Minimum Current Start-Up Method by Combined Use of Two Position-Sensorless Controls

A start-up method for reducing the start-up current of a permanent-magnet synchronous motor (PMSM) is proposed. Minimum current start-up is achieved by combining two position-sensorless control methods that require no harmonic injection. Position-sensorless control for low-speed regions utilizes induced voltage caused by the magnetic saturation of a PMSM with a conventional block commutation drive. During acceleration of the rotor, the position-sensorless control is switched to the second method, which is based on back electromotive force with a sinusoidal commutation drive. Since unconsidered switching may result in start-up failure when the proposed start-up method is used in applications with periodic load properties, a method to determine the correct timing to change the position-sensorless control in consideration of load variation is also proposed. The proposed methods are validated in start-up tests using a reciprocating compressor with a large periodic load torque.

Piston position estimation for an electro-pneumatic actuator at standstill

In this paper, a first strategy to reconstruct the piston position of a pneumatic cylinder supplied by two servovalves is proposed using only the chambers pressure measurements. This work focuses on the position observation at standstill. Starting from a classical model of this actuator, a transformation of the inputs is used. This way, for the first time, a link is established between electro-pneumatic actuators and Permanent Magnet Synchronous Motors (PMSM). This allows to apply PMSM zero speed observation strategies to electro-pneumatic actuators. Thus, following an observability analysis, a signal injection based methodology is used to ensure the observability of the electro-pneumatic system. A non-linear position observer is synthesized and a Lyapunov function is provided to ensure the global stability. Experimental results confirm the proposed strategy efficiency. The proposed technique constitutes a first step toward sensorless position control of electro-pneumatic actuators.

Position Sensorless Control of a Reluctance Synchronous Wind Generator Drive with an LC Inverter Filter

—A control structure for an inverter-fed high speed reluctance synchronous generator wind energy conversion system is proposed and investigated in this article. The novel combination of an LC inverter output filter and a hybrid position sensorless control method is used to ensure robustness and reliability of the system. The proposed LC inverter filter and position sensorless control method also allows the inverter unit to be stationed in the tower base instead of in the nacelle. With the LC filter, sinusoidal machine terminal voltages and reduced electromagnetic interference (EMI) from the tower supple cables are ensured. A new estimation method is developed to minimize current and voltages sensors in the drive system with the LC filter, whereby the machine’s stator quantities are estimated, requiring only parameter knowledge of the LC filter. The proposed hybrid position sensorless control algorithm uses the estimated stator quantities to estimate the rotor position. A high-frequency injection position sensorless control method is used at low speeds. The frequency of the high-frequency injection voltage is chosen close to the resonance frequency of the filter and machine model to amplify the high-frequency current response. Excellent dynamic performance of the proposed control drive system is obtained from a 9.6-kW laboratory reluctance synchronous generator drive system.

Sensorless control of hybrid magnetic bearings

A method of sensorless rotor position control in noncontact bearings by output parameters of the electromechanical energy converter is proposed. The physical essence of the method is as follows. As the displacement of an electromechanical energy converter rotor along the axes x and y varies, the conductivity of the air gap and, accordingly, of the magnetic conductivity of the air gap changes; i.e., in the case of the rotor displacement, additional harmonic components of the magnetic induction occur that create additional harmonic components of the electromotive force. The estimation of these harmonic components makes it possible to determine the displacement of the rotor without the use of rotor position sensors. The mathematical apparatus and the sensorless rotor position control algorithm based on this apparatus have been developed for practical implementation of the proposed method.

Rotor Position Sensorless Control of BLDC Motor based on Back Emf Detection Method

In this paper an improved back emf detection method is proposed. The motor neutral voltage is elemenated and the phase back emf zero crossing point can be directly extracted by detecting voltage difference between the phase terminal and the midpoint of the dc link. Here filtering circuit is not needed and the BLDC motor is provided with PWM control of 100% duty ratio which is presented in this paper. To perform the inverter commutation, there is a need of six commutation signals which is obtained by sensing only one of the three phase terminals that reduces the cost of the sensing circuit. The reduction of the imbalance in the six commutation signals which are caused by the asymmetrical behavior of the three phase windings in BLDC motor had been reduced in a varied speed range. It simplifies the starting procedure and achieve the motor performance over a wide speed range. This proposed method is analyzed through the simulation results using MATLAB Simulink. DOI: http://dx.doi.org/10.11591/telkomnika.v14i2.7423

Distributed containment control and state observer design for multi-agent robotic system

Aiming at the distributed containment control problem for multi-agent robotic system with stationary leaders, a position-sensorless control strategy is proposed based on binocular visual servo and feedback dissipative Hamilton theory. Firstly, the topological relationship among the robots is built by using directed graph, which makes each follower determine its neighbour robots. Secondly, a binocular visual servo model is established, so as to describe the dynamic information of the tracking target point for each follower through the neighbour robots' image information. Thirdly, the distributed containment controllers are designed based on the pre-feedback control strategy and feedback dissipative Hamilton theory; furthermore, in the case that each follower is not equipped with internal position sensor, the full-order state observers are developed by using the 'expansion + feedback' method, and then realise the position-sensorless control. Finally, a simulation is carried out on multiple two degrees-of-freedom (DOF) robots, and results show the validity of the proposed control strategy.

Audible Noise Reduction Method in IPMSM Position Sensorless Control Based on High-Frequency Current Injection

Methods for sensorless control involving the injection of a high-frequency signal in the low-speed range of the Interior Permanent Magnet Synchronous Motor (IPMSM) have been proposed. However, audible noise is a concern in these methods. We propose a method to reduce the audible noise due to a high-frequency current by minimizing the injection signal amplitude suitable for IPMSM driving states.

Adaptive Signal Injection Method Combined with EEMF-based Position Sensorless Control of IPMSM Drives

Adaptive Signal Injection Method Combined with EEMF-based Position Sensorless Control of IPMSM Drives

Variable-Gear EV Reluctance Synchronous Motor Drives—An Evaluation of Rotor Structures for Position-Sensorless Control

The reluctance synchronous motor (RSM) is identified to be well suited for the variable-gear (VG) electric vehicle (EV) drive. It is shown in this paper, however, that the RSM drive's position-sensorless capability is limited at zero or very small current magnitudes due to a limited saliency magnitude. In this paper, a novel epoxy-resin-casted rotor with no iron ribs is proposed to increase the saliency of the RSM at zero reference current. This rotor RSM is simulated in finite-element (FE) analysis, built, evaluated, and compared with conventional flux barrier rotor RSMs. The effect of rotor skewing on the position-sensorless control (PSC) capability of the RSM is also evaluated by means of FE analysis and measurements. Other performance aspects are also considered in this paper. It is concluded that, overall, the skewed epoxy-resin-casted rotor RSM drive has no PSC problems in the entire load and speed regions and is well suited for VG EV drives.

Analysis of the Sensorless PMSM Control Technique in the Full Speed Section

A novel position sensorless control strategy integrated with full section and high precision for a permanent magnet synchronous motor (PMSM) applied to wind power pitch was proposed in the paper. Based on high frequency signal, where three-phase triangular carrier spwm is injected and the state current response is detected to accurately estimate the rotor position in the still and low speed, which doesn’t rely on the non-ideal features. Based on BEF PMSM mathematic model, the phase locked loop technique is used to accurately detect the rotor position in the middle and high speed. the Finally, experiment on a 10 KW pith system demonstrates that the proposed method is effective and is capable of achieving more accurate control in the full speed section.