High Frequency Signal Injection Method Research Articles

Study on QEMF Model and Adaptive Full-Order Observer Design for Universal Sensorless Control of IPMSMs

Quadratic extended electromotive force (QEMF) model enabled the use of traditional high-speed adaptive estimation methods combined to high-frequency signal injection (HFSI) for full-range sensorless position control of interior permanent magnet synchronous motors (IPMSMs). However, the first QEMF model presented in literature only works with HFSI in the q-axis, due to the QEMF being a function of the q-axis current derivative. The q-axis HFSI is known to produce undesired torque ripple. Furthermore, q-axis signal injection can be insufficient for low-speed position estimation in IPMSMs with low salience. A recent study demonstrated that the QEMF concept can be modeled as a function of the d-axis current derivative. In this paper, the influence of d-axis HFSI on QEMF is investigated and compared to the q-axis HFSI method. Furthermore, the electromotive force based observers are usually designed for medium to high-speed operation. Here, the adaptive full-order observer is adapted in order to achieve universal sensorless control through QEMF based d-axis HFSI. The state observer and adaptive law are designed by a cascade methodology, which guarantees accurate EEMF estimation and robustness throughout the entire operating speed range. Experimental results are presented in order to validate the proposed method and analysis under full-range sensorless control.

Speed Estimation of Induction Motor at Low and Zero Speed using High Frequency Signal Injection for Rotor Slot Harmonics Detection

Rotor position estimation based on high frequency signal injection method represents the interesting way to provide the high performances of the AC drives sensorless controlled at low or near zero speed range. So, this method requires the existence of saliencies inside the IM particularly the presence of the slots where their design constitutes the main advantageous to exploit its effect for rotor speed monitoring. First, the present paper exposes a model of the induction machine including slotting effects which it can be exploited in order to extract the harmonic saliency created by rotor slotting. Second, the high frequency signal injection method is used in order to allow tracking the characteristic harmonic saliency due to rotor slotting from which the rotor position and speed may be estimated. A High frequency voltage signal injection creates a high frequency current modulated by the saliencies presented inside the machine. To extract information about rotor position, the resulting stator current treads to heterodyning process to eliminate the disturbance components and subsequently the rotor position may be extracted by a closed-loop observer. Simulation results are shown in order to verify the validity of the proposal and to confirm the effectiveness of estimation method at zero frequency.

Displacement sensorless control of a bearingless induction motor based on modified high-frequency signal injection

ABSTRACT To enhance the rotor radial displacement identification accuracy of a bearingless induction motor (BIM) in displacement sensorless control, a displacement sensorless control strategy based on modified high-frequency signal injection is proposed. Firstly, a BIM flux linkage equation is analyzed, and by integrating the principle of the conventional high-frequency signal injection method, a self-detection model for the BIM rotor radial displacement is established. Secondly, a cascade notch filter and a low-pass filter are used in the signal demodulation process of the modified high-frequency signal injection. This strategy enables the DC component relevant to rotor displacement to be extracted from the high-frequency current，and obtains the rotor radial displacement equations. Finally, compared with the conventional high-frequency signal injection control, the proposed BIM displacement sensorless control system based on the modified high-frequency signal injection has higher displacement identification accuracy under different operation conditions, such as no-load, sudden load, and radial displacement mutation, as shown in simulation and experimental results. Overall, the motor performs well in terms of speed and suspension.

An Amplitude-Adaption High-Frequency Signal Injection Method for SynRMs at Zero-Low Speed

An Amplitude-Adaption High-Frequency Signal Injection Method for SynRMs at Zero-Low Speed

Improved Parameter Identification of SPMSM Using High-Frequency Signal Injection Methods at Standstill

Improved Parameter Identification of SPMSM Using High-Frequency Signal Injection Methods at Standstill

Enhanced Linear ADRC Strategy for Sensorless Control of IPMSM Considering Cross-Coupling Factors

Estimation of rotor coordinate system by high-frequency (HF) signal injection is an effective sensorless control strategy, which can solve the decoupling problem of position information of interior permanent magnet synchronous motor (IPMSM) in the low-speed range. However, the inductance cross-coupling phenomenon caused by magnetic saturation will lead to a decline in the accuracy of rotor angle extraction, resulting in a serious deterioration of the sensorless control performance. To solve this problem, an HF signal injection method considering <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d-q</i> axis coupling inductance is proposed to estimate HF inductance and the rotor angle. The estimated HF inductor combined with the current loop enhanced linear active disturbance rejection control (ELADRC) is used in the current loop control to estimate the disturbance and improve the current regulation quality of the current control system. Furthermore, the stability and the tracking performance of the enhanced LADRC are analyzed theoretically. Finally, the stability of a closed-loop IPMSM drives system based on ELADRC considering HF inductance is analyzed. The experimental results of a salient pole IPMSMs driver verify the effectiveness and practicability of the scheme.

Speed Regulation and Optimization of Sensorless System of Permanent Magnet Synchronous Motor

Aiming at the problems of speed overshoot, slow convergence and poor anti-interference in the control of permanent-magnet synchronous motors (PMSMs) without a position sensor, a pulse vibration high-frequency signal injection method for a permanent-magnet synchronous motor with an improved sliding mode control was designed. Firstly, the improved approach rate function is combined with the improved non-singular fast terminal sliding mode surface to design the non-singular fast terminal sliding mode controller (NFTSMC), which is used in the speed loop to improve the speed convergence ability and reduce its overshoot. Secondly, in order to eliminate the influence of the band-pass filter on the system bandwidth in the traditional high-frequency injection method, a pulse vibration high-frequency signal injection method that injects high-frequency voltage signals and synchronous current signals into the d^ axis of the estimated two-phase rotation coordinate system d^q^ and the αβ axis of the two-phase stationary coordinate system αβ was designed to estimate the motor position and speed to achieve sensorless control. Finally, the above control strategy was compared with the speed loop PI and the traditional sliding mode controller (SMC) of the speed loop, respectively. The simulation and experimental results show that whether it is a no-load variable speed or fixed speed loading, the above control strategy can effectively reduce the speed overshoot, accelerate the speed convergence and improve the load capacity of the system.

Implementation of a new flux rotor based on model reference adaptive system for sensorless direct torque control modified for induction motor

Introduction. In order to realize an efficient speed control of induction motor, speed sensors, such as encoder, resolver or tachometer may be utilized. However, some problems appear such as, need of shaft extension, which decreases the mechanical robustness of the drive, reduce the reliability, and increase in cost. Purpose. In order to eliminate of speed sensors without losing. Several solutions to solve this problem have been suggested. Based on the motor fundamental excitation model, high frequency signal injection methods. The necessity of external hardware for signal injection and the adverse influence of injecting signal on the motor performance do not constitute an advantage for this technique. Fundamental model-based strategies method using instantaneous values of stator voltages and currents to estimate the rotor speed has been investigate. Several other methods have been proposed, such as model reference adaptive system, sliding mode observers, Luenberger observer and Kalman filter. The novelty of the proposed work consists in presenting a model reference adaptive system based speed estimator for sensorless direct torque control modified for induction motor drive. The model reference adaptive system is formed with flux rotor and the estimated stator current vector. Methods. The reference model utilizes measured current vector. On the other hand, the adjustable model uses the estimated stator current vector. The current is estimated through the solution of machine state equations. Practical value. The merits of the proposed estimator are demonstrated experimentally through a test-rig realized via the dSPACE DS1104 card in various operating conditions. The experimental results show the efficiency of the proposed speed estimation technique. Experimental results show the effectiveness of the proposed speed estimation method at nominal speed regions and speed reversal, and good results with respect to measurement speed estimation errors obtained.

Hybrid Active Flux Observer to Suppress Position Estimation Error for Sensorless IPMSM Drives

Harmonics and drifts are found in the position estimation errors of high-frequency signal injection (HFI) methods. To suppress the position estimation error, a hybrid active flux observer with disturbance rejection for both HFI method and model-based method is proposed. It fuses the position information from traditional HFI method and model-based method as the input of a disturbance observer, the estimated disturbance output can compensate measurement error for the two methods. Then a reduced-order natural speed observer is connected in a cascaded form to reject motor mechanical disturbance by estimating the load torque. Besides, a stator resistance identification algorithm is proposed, which is proved stable near zero frequency under persistent excitation condition. A tuning guideline for the whole algorithm is elaborated based on a rigorous stability analysis. Effective experiments and simulations verify the feasibility of the proposed scheme on a 0.75-kW interior permanent magnet synchronous motor drive platform.

Special‐angle‐based signal injection sensorless control of IPMSM for suppressing multiple zero‐crossings of phase current

Pulsating high-frequency signal injection has the problem of multiple zero-crossings when the phase current crosses zero-point, which deteriorates the distortion of high-frequency current caused by the zero-current-clamping effect. Thus, the accuracy of position observation is affected. To suppress multiple zero-crossings, improved sinusoidal and square-wave signal injection schemes are proposed. First, the relationship between the injection angle of the high-frequency signal and the phase of the high-frequency response current amplitude function is analysed. Based on the relationship, a special injection angle is calculated. By injecting the pulsating signal in the obtained special angle, the phase of the high-frequency current is shifted. The amplitude of the high-frequency response current is minimum when the fundamental frequency current crosses zero, thus reducing zero-crossing points of phase current. Furthermore, the error signal extraction scheme applicable to arbitrary angle injection is designed to observe rotor position. The proposed high-frequency signal injection method minimises the zero-crossings of the phase current at any value of the torque angle. Both of the novel sinusoidal pulsating injection sensorless control scheme and square-wave injection sensorless control scheme are confirmed by experiments on a 2.2-kW interior permanent magnet synchronous motor (IPMSM) drive platform.

Finite Position Control of Interior Permanent Magnet Synchronous Motors at Low Speed

This article presents a new scheme to extract the rotor position angle of interior permanent magnet synchronous motors using a high-frequency signal injection method with an iterative strategy. An iterative strategy based on the binary principle is proposed to reduce the computational burden using discrete rotor position angles. These discrete rotor position angles are obtained from the angle space, which is divided into several separate sectors and employed to calculate the defined cost function that generates the optimal rotor position angle. With the number of iterations increasing, the accuracy of the iterative search strategy will increase geometrically. Finally, a series of experimental tests have been carried out to compare the performances of the proposed and the conventional low-speed sensorless methods. Experimental results have verified the effectiveness of the proposed low-speed sensorless scheme.

High Frequency Signal Injection Sensorless Control of Finite-Control-Set Model Predictive Control With Deadbeat Solution

Due to lack of the pulsewidth modulation module, it is difficult to implement conventional high frequency signal injection (HFSI) sensorless control method on finite-control-set model predictive control. Hence, this article proposes a simple method by using the deadbeat solution, in which the current tracking error in the cost function is transformed to the voltage reference tracking error. Correspondingly, an HF voltage reference is added to the cost function and the injection can be achieved without modifications of existing HFSI methods. Moreover, the influence of parameter mismatch on the proposed position estimation method is analyzed. The proposed method shows robustness to parameter mismatches. The effectiveness of the proposed method is verified by experiments with a conventional pulsating signal injection method.

Sensorless Control of PMSM in Low Speed Region Using HF Pulse Signal Injection Method

Abstract The sensorless control of the permanent magnet synchronous motor (PMSM) has attracted wide attention due to its economic and safety benefits. A fast and high-precision rotor-position estimation is necessary for the implementation of sensorless control. In low-speed region, high frequency (HF) signal injection methods are mostly adopted. They suffer to bandwidth deterioration as some digital filters must be included in the current feedback loop or the speed observation signal processing. The HF signal injection method based on the injection of voltage pulses is presented in this paper together with its implementation in MATLAB/Simulink. The method is based on the injection of voltage pulses where injection itself is separated from the motor control algorithm. The simulation results show that the proposed method has good dynamic performance for the sensorless control of PMSM.

Speed Sensorless Control Based on Initial Rotor Position Detection for EESM

Electrically excited synchronous motor (EESM) is widely used in many large equipment drives because of its strong overload capacity, high efficiency, and adjustable power factor. The research and development of a high-performance EESM control system can realize the high combination of energy-saving speed regulation and green environmental protection and has a high social effect and economic value. In this paper, the signal injection method is used to obtain the initial rotor position information of EESM. Sliding Fourier transform is used to improve the initial position angle detection method based on the rotor signal injection method, and the improved method is compared with the traditional voltage integration method. Rotor high-frequency signal injection method was used to detect the rotor position information of the motor during operation, and the influence of the damping winding on the rotor signal injection method was analyzed. On the premise that the damping winding had no influence on the method, a method of obtaining the rotor position information of EESM without a speed sensor was designed. Finally, the speed sensorless regulation system using the initial rotor position detection method is simulated, which verifies the accuracy of the proposed speed sensorless control scheme.

Position sensorless control system of SPMSM based on high frequency signal injection method with passive controller

Position sensorless control system of SPMSM based on high frequency signal injection method with passive controller

Position sensorless control system of SPMSM based on high frequency signal injection method with passive controller

Position sensorless control system of SPMSM based on high frequency signal injection method with passive controller

Model Predictive Current Control With Online Parameter Estimation for Synchronous Reluctance Machine Controlled by High-Frequency Signal Injection Position-Sensorless

Accurate machine parameters and rotor position information are essential in vector-controlled motor drive systems. However, machine parameter variations by various factors such as the current and the temperature degrade the performance of vector control. Also, a position sensor such as an encoder and a resolver increases the drive system cost. This paper proposes model predictive current control (MPCC) with the online parameter estimation for synchronous reluctance machines controlled by a high-frequency signal injection position-sensorless method. This approach removes the need for accurate knowledge about the system and eliminates the need for the position sensor. The proposed method adopts a recursive least-square (RLS) to estimate the electrical machine parameters in real-time. The estimated parameters are used for the deadbeat continuous control set (CCS) MPCC and the position-sensorless control. The high-frequency signal injection method is modified to be suitable for the proposed CCS-MPCC method, ensuring stable operation in the low-speed regions. Simulation and experimental results are provided to verify the performance of the proposed control method.

Investigation of Signal Injection Methods for Fault Detection of PMSM Drives

Inter-turn short-circuit fault (ISF) is a typical incipient fault of the PMSM, which could be detected by high frequency (HF) signal injection method with high resolution. However, the performance comparisons and key parameter selections for various signal injection methods remain untouched. In this paper, different HF injection signals, including rotating high frequency voltage (RHFV), pulsating high frequency voltage (PHFV) and rotating high frequency current (RHFC), are put forward and compared by extracting the HF fault features in zero-sequence voltage space. Since the RHFV injection method has the advantages of high resolution and simple control structure, the fault features under the RHFV signal injection with different parameters are studied. In order to obtain ISF detection resolution as high as possible, the frequency of the RHFV signal is suggested to be near half the PWM frequency of the PMSM inverter. Simulations and experiments are carried out and the results verify the effectiveness of the theoretical analysis.

Low-Speed Sensorless Control for the Interior Permanent Magnet Synchronous Motors with Sliding Discrete Fourier Transform

An efficient estimation of the rotor position has always been a premise of the reliable operation for the interior permanent magnet synchronous motors (IPMSM), especially for low-speed conditions because of the small back electromotive force (EMF) and low signal-to-noise ratio (SNR). The commonly used observation method, e.g., sliding mode observer (SMO), is suitable for these surface mounted motors and has no great adaptability to the saliency. In this paper, a novel rotor position (including the real-time position and initial position) estimation method was proposed based on the traditional high-frequency signal injection method. Firstly, high-frequency signals were injected to induce the high-frequency current components which contain the rotor position information. Then, the sliding discrete Fourier transform (SDFT) algorithm was used to extract the amplitudes of the induced current components which could be used to get the real-time and initial rotor positions by a proportional integral (PI) regulator and a polarity identification. Lastly, with the established experiments’ platform, the estimation tests of the rotor position at a low speed have been completed to make verification of the effectiveness of the approach studied in this paper.

Research on sensorless control system of low speed and high power PMSM based on improved high frequency signal injection

With more and more applications of high-power PMSM in low-speed applications, the accuracy of the control system has also become more demanding. It is difficult to detect the position and control the speed of the motor according to the counter EMF because its amplitude is small. This paper adopts an improved high frequency signal injection method and the filtering method of single synchronous shafting filter and PLL, a set of high-power sensorless AC speed regulating system is designed based on the NPC three-level back-to-back converter with IGBTs which improves the robustness and control accuracy of low-speed high-power PMSM. The experimental and simulation results show that the control system meets the design requirements of engineering application.