High-frequency Injection Method Research Articles

Low-speed sensorless control of permanent magnet synchronous motors via the Cauchy–Gauss hybrid mutation particle swarm optimization algorithm

In the process of tracking the speed and rotor position of a permanent magnet synchronous motor, the conventional proportional–integral (PI) control method has difficulty satisfying the requirements of the control system. Therefore, an alternative based on particle swarm optimization is proposed in this article. To improve the optimization performance, a nonlinear differential decreasing inertia weight and an asynchronous time-varying learning factor are adopted. A Cauchy–Gauss hybrid mutation strategy is introduced to prevent the algorithm from falling easily into a local optimum. Then, the high-frequency injection method is used to estimate the rotor speed and position. Simulations and experiments show that the proposed Cauchy–Gauss hybrid mutation particle swarm optimization method has good dynamic performance and anti-interference capability and can satisfy the requirements of the system.

Vibration analysis and dynamic performance improvement of high-frequency injection method

This paper analyzes and compares the typical rotating high-frequency voltage injection (RTHF) method and the typical pulsating high-frequency voltage injection (PSHF) method in terms of torque ripple and vibration. Analysis and experiment results indicate that the PSHF performs better when it comes to torque pulsation and vibration. In addition, it is more suitable for rim motors which have strict restrictions on vibration. However, the estimated rotor position in PSHF has multiple convergence points. In addition, the filters used in PSHF can degrade the dynamic response of the PMSM sensorless field oriented control (SLFOC) system. An improved PSHF method compensated by Hall signals is proposed to accelerate the estimation process and improve the system stability in the presence of sudden load disturbances. The improved method is verified on an 11 kW rim motor experimental platform.

A New Method for Detecting Initial Position of IPMSM Rotor

Aiming at the speed sensorless control system of permanent magnet synchronous motor which embedded in rotor magnet steel, a new method for detecting the initial position of the rotor is proposed in this paper. This method is injecting a high-frequency rotating voltage to generate a high-frequency current in the stator windings that contains the spatial position information of the rotor. Compared with the traditional high-frequency injection method, this paper uses Discrete Fourier Transform (DFT) to demodulate high-frequency current. It avoids the signal phase delay caused by the use of a large number of filters when demodulating the traditional heterodyne method. At the same time, this method has nothing to do with the initial phase of the injected signal. Compared with the heterodyne method, the extracted rotor position angle is more accurate, and the structure is simple Number system. The validity and feasibility of the method are verified by simulation and experimental platform based on dSPACE.

Initial position detection for Selective Compliance Assembly Robot Arm manipulator joint based on an improved high-frequency injection method

Starting oscillation or slow response will occur if the initial position of the motor used in the Selective Compliance Assembly Robot Arm manipulator is not known. To obtain the initial position of the motor, an improved high-frequency injection method is proposed. First, a high-frequency rotating voltage signal is injected into the stationary coordinate system, and the initial position information is extracted by the heterodyne method. Second, an improved position tracking observer is proposed to estimate the rotor position. Taking the joint of a four-axis Selective Compliance Assembly Robot Arm as an object, a special position servo drive system is designed. The design principle, simulation analysis and experimental verification of the proposed method are presented, respectively. The results show that the initial position of the motor can be estimated by the proposed method, enabling high torque and fast start of the Selective Compliance Assembly Robot Arm manipulator.

Diagnosis and Remediation of Single-Turn Short Circuit in a Multiphase FSCW PM Machine Based on T-type Equivalent Circuit

Single-turn short circuit (STSC) refers to the most severe turn fault condition in which the number of shorted turns is only one. Since winding inductance is proportional to the square of number of turns, STSC suffers from significantly large circulating current inside the faulted turn. The objective of this article is to provide practical approaches that enable fault detection and postfault operation. A previously developed T-type equivalent circuit laid a solid foundation for the proposed methods. High-frequency injection and signal processing method are carried out for reliable online fault diagnosis, while postfault operation is based on shorting the remaining turns as well as instantaneous power balance theory. Experimental results confirm the effectiveness of the proposed methods.

A resilient adaptive sliding mode observer for sensorless AC salient pole machine drives based on an improved HF injection method

In high frequency (HF) injection methods, classical tracking algorithms are used to estimate the rotor position for sensorless alternating current (AC) salient pole machines. These algorithms were dependent on AC machine inductances which are characterized by their large variations. To overcome this dependency, a new approach based on using only the sign of the rotor position estimation error (instead of using rotor position estimation error) is proposed. This approach has also the advantage of removing the low-pass filter (LPF) used to separate the HF component from the rotor position information. Consequently, only the first order sliding mode observer can be employed to estimate the rotor position, as only the sign of the rotor position estimation error is known. To avoid the well known chattering phenomena of this observer, an adaptive step-by-step sliding mode observer is proposed as an alternative solution to estimate the rotor position of the machine. The stability study of the proposed observer is analyzed both in transient/steady state ranges and a procedure for gains tuning is then given. The performance of the proposed algorithm is tested on simulation and experimentally in the framework of a representative small-scale electric propulsion benchmark, used in automotive applications. Moreover, a comparison study is conducted with respect to some existing tracking algorithms in order to illustrate the well-founded of the designed algorithm.

Research on PMSM Low-speed Sensorless Control Strategy based on Rotating High Frequency Injection Method

In this paper, by studying the Permanent Magnet Synchronous Motor (PMSM) position sensorless control strategy, a method for error compensation of current responsed by high frequency error signal is proposed. Since the high-frequency carrier current contained in the stator current causes the erroneous adjustment of the current regulator, the control system contains a high-frequency error signal, which affects the motor rotor position and speed estimation accuracy. The high-frequency error voltage signal is extracted in the stationaryα − β coordinate system, and the high-frequency error response current in the stator current is estimated, and the estimation system is compensated. The PMSM position sensorless control system based on the rotating high frequency voltage injection method and the Matlab-Simulink system model of the error compensation are established. The results show that the speed and position estimation are more accurate after error compensation, and the steady-state error is smaller, which improves the smoothness of the motor at low speed.

A High Frequency Injection Technique With Modified Current Reconstruction for Low-Speed Sensorless Control of IPMSMs With a Single DC-Link Current Sensor

This paper proposes a high frequency injection technique applied for low-speed sensorless control of interior permanent magnet synchronous machines (IPMSM) with a single dc-link current sensor. The three-phase currents, which can be reconstructed by the measurement of a dc-link current sensor, always suffer from the immeasurable regions. The most challenging problem exists in the low modulation region, where no phase current can be measured by the dc-link current sensor, and it is rarely solved without PWM modifications. This paper proposes a six-direction square wave high frequency injection method to extend the voltage vector to the measurable region to achieve the three-phase current reconstruction and saliency-based sensorless control without modifying the space vectors of the pulse width modulation (PWM). In addition, the paper comes up with a modified reconstruction scheme to reduce the reconstruction error and improve the accuracy of the position estimation. This low-speed sensorless strategy using a single dc-link current sensor is implemented in dSpace platform and the performance is evaluated by experiments.

Combined Active Flux and High-Frequency Injection Methods for Sensorless Direct-Flux Vector Control of Synchronous Reluctance Machines

This paper proposes a sensorless control scheme for synchronous reluctance (SyR) motor drives based on the direct-flux vector control (DFVC) method. The control operates in stator-flux-oriented coordinates, using constant switching frequency. A hybrid position and speed observer is proposed, based on the combination of the active flux concept and high-frequency signal injection and demodulation. The two methods are fused together to form a unique position and speed estimate signals, with seamless transition between the two models based on reference speed. The proposed observer covers a wide speed range, from standstill operation at full load to flux weakening (FW). Furthermore, it is inherently immune from position estimation error caused by cross saturation, as proven mathematically and experimentally. The motor is operated according to the maximum torque per ampere (MTPA) law. Specific issues related to MTPA around zero torque are addressed in this paper. The proposed control technique extends the range of application of the DFVC to encoderless drives, and can be usefully adopted in those applications where both zero-speed and FW speed range operations are necessary, such as home appliances, or automotive and aerospace actuators and generators. A 2.2-kW SyR motor prototype was tested to verify the feasibility of the proposed method. Key tuning aspects are addressed in this paper.

A Novel Sensorless Initial Rotor Position Estimation Method for Permanent Magnet Synchronous Motors

<span style="color: black; font-family: 'Times New Roman','serif'; font-size: 9pt; mso-fareast-font-family: 新細明體; mso-fareast-theme-font: minor-fareast; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA; mso-bidi-font-style: italic;" lang="EN-US">This paper presents a high efficiency initial rotor position estimation method for Permanent Magnet Synchronous Motors (PMSM). The approach uses the viable inductance model to analyze the optimal motor injection sine wave frequency as the motor’s test signal. Unlike other high-frequency injection methods, this approach does not require trial and error experiments. The injection frequency is identified by programmable simulations using Matlab. Experimental evaluation of 3-phase PMSM showed that this injection frequency optimization method works successfully. The proposed method can find the optimal injection frequency without experimentation, and outperforms other test signals in terms of accuracy, vibration quantity and noise. This microprocessor-developed 3-phase PMSM control driver can be applied to electrical appliances, machine tools and automation.</span>

Adaptive controller with an improved high‐frequency injection technique for sensorless synchronous reluctance drive systems

This paper proposes an adaptive controller with an improved high-frequency injection method for sensorless synchronous reluctance drive systems. A mathematical model is presented to show that the use of a high-frequency injection method that takes into account the effects of unequal mutual-inductances and the influence of speed reduces the rotor position estimation error. The adaptive speed control algorithm offers improved transient performance in comparison to typical proportional–integral (PI) controllers that are employed in sensorless drive systems. To demonstrate the viability, the proposed adaptive controller and the modified high-frequency injection method are implemented using a TMS-320F-28335A digital signal processor to control a 500 W prototype synchronous reluctance motor drive. Experimental results are presented to show that the transient, load disturbance, and tracking responses of the proposed drive system are superior in comparison to a drive that uses a PI controller. Both experimental and theoretical analyses clearly indicate that the proposed high-frequency injection method with an adaptive speed-loop controller offers improved performance in adjustable speed synchronous reluctance drive systems.

Performance of a Sensorless Controlled Concentrated-Wound Interior Permanent-Magnet Synchronous Machine at Low and Zero Speed

This paper concerns the sensorless direct torque and flux control (DTFC) of a 14-pole/18-slot, fractional-slot concentrated winding interior permanent-magnet synchronous machine (IPMSM). The dynamic performance of the prototype machine at or near base speed was found to be comparable to a distributed wound IPMSM. However, the lowest operating speed of the machine under sensorless control scheme was only about 30% of the base speed. This paper demonstrates experimentally that this lack of performance can be overcome substantially by using the extended-flux linkage model and high-frequency (HF) injection methods. By using the extended-flux model, the lowest operable speed was reduced from 30% to 5% of the base speed. In order to operate the machine, at a standstill under sensorless control, the HF injection method was employed. Factors that affect the performance at zero speed were investigated systematically.

Position Self-Sensing Evaluation of Novel CW-IPMSMs With an HF Injection Method

This paper introduces two different novel designs of interior permanent-magnet synchronous machines with concentrated windings, which are attractive to a self-sensing control system. The new machines have some advantages: lower subharmonics of air-gap flux density and magnetomotive force and lower machine losses, including eddy current losses. The machines have been adapted for self-sensing applications by using a high-frequency (HF) injection method. The main machine parameters affecting the estimation accuracy are analyzed such as fundamental frequency saliencies, cross saturation, HF inductance, HF resistance, and harmonic distortion due to multisaliencies. The experimental results verify that the novel machines can reach very high performance with good self-sensing properties regarding the accuracy of the estimated position/speed of electric drives even without the multisaliency decoupling compensation method.

A New Approach for Estimation of Speed/Position of Two-Phase Induction Machine Using Virtual High Frequency Injection Method

This paper describes a new approach to estimate rotor angle of two-phase induction machine from measured terminal voltages and currents using virtual high frequency injection method for sensorless vector control. The proposed scheme is independent from load variation since the rotor angle is derived by using only the injected d, q axis voltage component. The difference between the classical high frequency injection method and the novel virtual one is in injection voltage to the mathematical model of the machine not to the stator of the machine. The mathematical principle of the proposed technique and its implementation are presented. Computer simulations and experimental results are also included for verification

Position Self-Sensing Evaluation of a FI-IPMSM Based on High-Frequency Signal Injection Methods

The flux-intensified interior permanent-magnet synchronous machine (IPMSM) (FI-IPMSM) lends itself to designing for good self-sensing properties. This paper begins by evaluating the self-sensing position estimation performance of a suitably designed FI-IPMSM machine using different high-frequency injection methods. This paper then uses an alternative square-wave injection method to estimate the FI-IPMSM rotor position. The experiment results show that the estimation accuracy and system robustness are improved. It is known that secondary saliencies and saliency offset caused by the saturation of the machine can degrade the estimation accuracy. This paper also includes modeling, measurement, and decoupling methods that mitigate these undesirable effects, which are also implemented using an experimental FI-IPMSM. Estimation accuracy and torque ripple caused by the injection current are examined for this FI-IPMSM. Comparisons of the methods are presented.

A New High-Frequency Injection Method for Sensorless Control of Doubly Fed Induction Machines

This paper introduces a new method to solve the sensorless control problem for a grid-connected doubly fed induction machine (DFIM). The proposed method is based on high-frequency signal injection and the fact that the rotor of a DFIM can be seen as the rotating secondary of an induction transformer. The commonly used sensorless technique based on stator-flux linkage, aside from being parameter sensitive, does not work during fault ride through (FRT) conditions. Nevertheless, the proposed method is parameter independent and remains fully functional during FRT conditions. Moreover, as opposed to other high-frequency injection methods, the proposed method does not require rotor saliency. The mathematical principle of the proposed technique and its implementation are presented. Computer simulations and initial experimental results are also included for verification.

Implementation of high-performance sensorless interior permanent-magnet synchronous motor control systems using a high-frequency injection technique

This study proposes a high-performance sensorless interior permanent-magnet synchronous motor control system using a high-frequency injection technique. A new estimation method that uses both the high-frequency d-axis current and q-axis current to estimate the rotor position is investigated. By using the proposed method, the hypothesis-synchronisation signal used in the conventional high-frequency injection method can be eliminated. A 1.25 kHz, 15 V, sinusoidal waveform voltage is injected into the d-axis synchronous frame of the motor and then the high-frequency d-axis and q-axis currents can be measured to determine the rotor position of the motor. In addition, a new compensation method is developed to reduce the estimation position error because of the mutual inductance and saturation effect of the motor. By using this new method, the estimated rotor-position error is within ±2 electrical degrees. A digital signal processor, TMS-320-F2812, is used as the estimating and control centre. The experimental results show that the proposed method can be applied in both a sensorless speed control system and a sensorless position control system. The sensorless speed control system has fast response, good load disturbance response and good tracking response.

Ship electric propulsion with a sensorless permanent magnet synchronous motor: A simulation study

New general ships powered by electric propulsion always operate at low motor speeds. Popular sensorless vector control methods, including open loop and closed loop methods, are not reliable in this application. This is because the magnitude of back-electromotive force voltage is very small in the low speed region, and the performance of these methods is therefore significantly degraded. To overcome this problem, a high-frequency injection method is introduced in the control of the ship electric propulsion system. The injected periodic signal creates a high-frequency revolving field to act as a carrier. Then the desired information about the position angle of the motor can be retrieved. A simulation model of a ship electric propulsion system is established in Matlab/Simulink. The test results show that the newly proposed control system works stably with various ship operating conditions and robustly against speed variations. Its estimated position error is less than 0.3 rad. Moreover, the proposed sensorless vector control approach has been compared with the closed-loop-based model reference adaptive system. The comparison has demonstrated that the dynamic characteristics of the proposed control system are superior to the latter.

Experimental Verification of Positive Correlation Characteristics by Generalized High-frequency Voltage Injection Method

Through experiments, this paper newly validates analytical correlation characteristics between rotor and major-axis phases of high-frequency current trajectory caused by injection of the generalized high-frequency ellipse voltage.

A Sensorless PM Synchronous Motor Drive for Electric Washers

This paper presents a complex solution for whole speed range sensorless control of interior permanent magnet synchronous motor drives. To cover an entire speed range of IPMSM without position transducer, different sensorless techniques must be employed. Design and implementation of sensorless techniques for different operating speeds are described in this paper. Presented application has been implemented including the high frequency (hf) injection method and extended back EMF state observer on a single chip solution of DSC56F8300 series without any additional supportive circuitry. The extended back EMF algorithm with angular speed and position observer is suitable for sensorless control drive. It is also transferable for other motor types, e.g. synchronous reluctance- or synchronous one with 'smooth' rotor. The presented sensorless control has been proved in electric washer drive with very good operating properties.