Some Permanent Magnet Synchronous Motor (PMSM) Sensorless Control Methods based on Operation Speed Area

This paper compares some sensorless Permanent Magnet Synchronous Motor (PMSM) controls for driving an electric vehicle in terms of operating speed. Sensorless control is a type of control method in which sensors, such as speed and position sensors, are not used to measure controlled variables.  The controlled variable value is estimated from the stator current measurement. Sensorless control performance is not as good as a sensor-based system. This paper aims are to recommend a control method for the PMSM sensorless controls that would be used to drive an electric vehicle. The methods that we will discuss are divided into four categories based on the operation speed area.  They are a startup, low speed, high speed, and low and high-speed areas. The low and high-speed area will be divided into with and without switching.  If PMSM more work at high speed, the most speed area that is used, we prefer to choose the method that works at high speed, that is, the modification or combination of two or more conventional methods

Sensorless Control with Switching Frequency Square Wave Voltage Injection for SPMSM with Low Rotor Magnetic Anisotropy

High-frequency signal injection sensorless algorithms are widely studied and used for rotor angle estimation in PMSM at low speed or standstill. One of the main drawbacks of such methods is the acoustic noise connected to the voltage injection. In order to minimize this problem, it is advisable to increase the frequency of the injected signal. Thus, many studies focus on square-wave injection at the switching frequency, which is the maximum theoretical frequency. Since these methods exploit the rotor magnetic anisotropy, it is relatively easy to use them in interior PMSMs, where the rotor anisotropy is high. On the contrary, it is hard to exploit them in surface PMSMs, which have an almost symmetric rotor, although a low rotor magnetic anisotropy is still present. In this paper, a sensorless algorithm with switching frequency squarewave injection is developed for surface PMSMs. To increase the signal-to-noise ratio, current oversampling is exploited. The benefits of such a technique are demonstrated with experimental results on a 2 Nm SPMSM

Speed Sensorless Control of SPMSM Drives for EVs with a Binary Search Algorithm-Based Phase-Locked Loop

© 1967-2012 IEEE. This article presents a new method to extract accurate rotor position for the speed sensorless control of surface-mounted permanent-magnet synchronous motors (SPMSMs), based on the back electromotive force (EMF) information. The concept of finite control set-model predictive control is employed, and its cost function is related to the back EMF. An optimal voltage vector is selected from several given voltage vectors by comparing their fitness values. Moreover, the position space is divided into four sectors, and the fitness of each sector boundary is calculated and compared. The rotor position is first located in the sector surrounded by two boundaries that minimize the cost function. Then the selected sector is split into two parts, and the binary search algorithm is applied to reduce the sector area to improve the accuracy of position estimation. To overcome the drawback of the back EMF-based sensorless scheme, an I-f startup method is employed to accelerate the motor to the desired speed. An experiment has been carried out to compare the performance of the proposed method and the conventional phase-locked loop (PLL) in terms of steady-state and transient conditions

Dynamic Performance Analysis of a Five-Phase PMSM Drive Using Model Reference Adaptive System and Enhanced Sliding Mode Observer

This paper aims to evaluate the dynamic performance of a five-phase PMSM drive using two different observers: sliding mode (SMO) and model reference adaptive system (MRAS). The design of the vector control for the drive is firstly introduced in details to visualize the proper selection of speed and current controllers’ gains, then the construction of the two observers are presented. The stability check for the two observers are also presented and analyzed, and finally the evaluation results are presented to visualize the features of each sensorless technique and identify the advantages and shortages as well. The obtained results reveal that the de-signed SMO exhibits better performance and enhanced robustness compared with the MRAS under different operating conditions. This fact is approved through the obtained results considering a mismatch in the values of stator resistance and stator inductance as well. Large deviation in the values of estimated speed and rotor position are observed under MRAS, and this is also accompanied with high speed and torque oscillations

Motor control in aerospace, optimizing availability and acoustics

The objective of this research project was to investigate motor control methods applied to Permanent Magnet Synchronous Motors (PMSMs) for aerospace applications. In specific this research attempted to address two key issues that are critical in aerospace. Firstly the increase in system availability in case of a resolver failure by means of applying sensorless motor control methods. Secondly the reduction of acoustic noise generated from a motor drive. Reliability, availability and acoustics are key areas in a number of industries especially aerospace. With regards to the reliability and availability objective, a hybrid model/saliency based sensorless method was investigated that can take over motor control in case of a resolver failure. With regards to the objective on acoustics, the research attempted firstly to address the problem of acoustic noise from High Frequency Injection (HFI). A variant of the Pseudo Random High Frequency Injection (PRHFI) algorithm was thus developed aiming to reduce the perception of acoustic noise. While investigating HFI sensorless methods and observing their acoustic effects, the most novel contribution of this research was conceived. The concept of Active Noise Cancellation/Control (ANC) by means of High Frequency Injection (HFI) was thus created, implemented and presented in this thesis. The proposed availability and acoustic improvement algorithms were first simulated in Matlab/Modelsim and then tested on the Helicopter Electro-Mechanical Actuation System (HEMAS). The above hardware platform is a PMSM based drive used to control the swash-plate onboard a helicopter. The reliability enhancement sensorless observer was demonstrated successfully during testing and was shown to track the motor’s speed and angle. The acoustic suppression algorithms (Pseudo Random High Frequency Injection and High Frequency Injection Active Noise Cancellation) were also demonstrated successfully on the hardware platform by means of audio capturing using microphones and analysis within Matlab

Motor control in aerospace, optimizing availability and acoustics

The objective of this research project was to investigate motor control methods applied to Permanent Magnet Synchronous Motors (PMSMs) for aerospace applications. In specific this research attempted to address two key issues that are critical in aerospace. Firstly the increase in system availability in case of a resolver failure by means of applying sensorless motor control methods. Secondly the reduction of acoustic noise generated from a motor drive. Reliability, availability and acoustics are key areas in a number of industries especially aerospace. With regards to the reliability and availability objective, a hybrid model/saliency based sensorless method was investigated that can take over motor control in case of a resolver failure. With regards to the objective on acoustics, the research attempted firstly to address the problem of acoustic noise from High Frequency Injection (HFI). A variant of the Pseudo Random High Frequency Injection (PRHFI) algorithm was thus developed aiming to reduce the perception of acoustic noise. While investigating HFI sensorless methods and observing their acoustic effects, the most novel contribution of this research was conceived. The concept of Active Noise Cancellation/Control (ANC) by means of High Frequency Injection (HFI) was thus created, implemented and presented in this thesis. The proposed availability and acoustic improvement algorithms were first simulated in Matlab/Modelsim and then tested on the Helicopter Electro-Mechanical Actuation System (HEMAS). The above hardware platform is a PMSM based drive used to control the swash-plate onboard a helicopter. The reliability enhancement sensorless observer was demonstrated successfully during testing and was shown to track the motor’s speed and angle. The acoustic suppression algorithms (Pseudo Random High Frequency Injection and High Frequency Injection Active Noise Cancellation) were also demonstrated successfully on the hardware platform by means of audio capturing using microphones and analysis within Matlab

Modelling and practical set-up to investigate the performance of permanent magnet synchronous motor through rotor position estimation at zero and low speeds

This thesis provides a study for the rotor position estimation in SM-PMSMs, particularly at zero and low speeds. The method for zero rotor speed is based on injection of three high frequency voltage pulses in the motor stator windings. Then, the voltage responses at the motor terminals are exploited to extract the rotor position. Two approaches, modelling and practical implementations, are presented. The obtained results have showed a verification of a high-resolution position estimation (a position estimation of 1 degree angle), a simplicity and cost effective implementation and a no need for current sensors is required to achieve the estimation process. It should be noticed that the implementation of rotor position estimation at zero speed is only attended when the rotor is at standstill or very low speed. Therefore, the motor driver is not expected to be active at this condition. Thereby, the zero speed estimation does not provide a robust torque control. In future, this should be taking into consideration to overcome this drawback and to make the estimator more reliable. At low speed running, the primary goal is to start spinning the under test motors, and then the rotor position estimation is achieved. The motor spinning is based on adopting a virtual injected signal to generate the voltage components, Vα and Vβ, of the space vector pulse width modulation technique. Then, generating the eight space vectors is conducted through storing the standard patterns of the six space vector sectors in a memory structure together with the timing sequences of each sector. The presented strategy of motor running includes a proposed motor speed control scheme, which is based on controlling the frequency of the power signal, at the inverter output, through controlling the timing period of execution the power delivery program. The thesis presents a proposed method to achieve the estimation goal depends on tracking the magnetic saliency on one motor line voltage. Thereby, the rotor position estimation The introduced proposed method, for rotor position estimation at zero speed, verifies the following contributions: - Presents a simple and cost effective zero speed rotor position estimator for the motor under test. - The aimed resolution in this thesis is an angle 1 degree. IV - Adopting solely the measuring of motor terminal voltages. Eliminating the detection of the rotor magnet polarity as a necessary technique for completing the position estimation. At low speed running, the following contributions are verified: - Rather than a real frequency signal, a virtual injected signal is adopted to generate the voltage components, Vα and Vβ of the space vector pulse width modulation technique. - The proposed method for generating the eight space vectors is based on storing the standard patterns of the six sectors in a memory structure together with the timing sequence. - The strategy of motor speed control is based on controlling the period of execution the power delivery program. - The strategy of low speed rotor position employs one motor line voltage from which the low speed estimation is achieved