scholarly journals Sensorless Pedalling Torque Estimation Based on Motor Load Torque Observation for Electrically Assisted Bicycles

Actuators ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 88
Author(s):  
Riccardo Mandriota ◽  
Stefano Fabbri ◽  
Matthias Nienhaus ◽  
Emanuele Grasso
Keyword(s):  
External Disturbance ◽  
State Observer ◽  
Position Estimation ◽  
Load Torque ◽  
Estimation Errors ◽  
Position Information ◽  
Longitudinal Dynamics ◽  
Rotor Position ◽  
Electrically Assisted ◽  
Motor Load

The need for reducing the cost of and space in Electrically Assisted Bicycles (EABs) has led the research to the development of solutions able to sense the applied pedalling torque and to provide a suitable electrical assistance avoiding the installation of torque sensors. Among these approaches, this paper proposes a novel method for the estimation of the pedalling torque starting from an estimation of the motor load torque given by a Load Torque Observer (LTO) and evaluating the environmental disturbances that act on the vehicle longitudinal dynamics. Moreover, this work shows the robustness of this approach to rotor position estimation errors introduced when sensorless techniques are used to control the motor. Therefore, this method allows removing also position sensors leading to an additional cost and space reduction. After a mathematical description of the vehicle longitudinal dynamics, this work proposes a state observer capable of estimating the applied pedalling torque. The theory is validated by means of experimental results performed on a bicycle under different conditions and exploiting the Direct Flux Control (DFC) sensorless technique to obtain the rotor position information. Afterwards, the identification of the system parameters together with the tuning of the control system and of the LTO required for the validation of the proposed theory are thoroughly described. Finally, the capabilities of the state observer of estimating an applied pedalling torque and of recognizing the application of external disturbance torques to the motor is verified.

scholarly journals Rotor Position Estimation Approaches for Sensorless Control of Permanent Magnet Traction Motor in Electric Vehicles: A Review

2021 ◽  
Vol 12 (1) ◽  
pp. 9
Author(s):  
Yong Li ◽  
Hao Wu ◽  
Xing Xu ◽  
Xiaodong Sun ◽  
Jindong Zhao
Keyword(s):  
Permanent Magnet ◽  
Sensorless Control ◽  
Position Estimation ◽  
Control Technology ◽  
Permanent Magnet Motor ◽  
Traction Motor ◽  
Position Information ◽  
Rotor Position ◽  
Control Techniques ◽  
Speed Range

Permanent magnet traction motor has the advantages of high efficiency, high power density, high torque density and quick dynamic response, which has been widely used in the traction field of electric vehicle. The high-performance control of permanent magnet traction motor depends on accurate rotor position information, which is usually obtained by using mechanical position sensors such as hall sensor, encoder and rotary transformer. However, the traditional mechanical sensor has the disadvantages of high cost, large volume and poor anti-interference ability, which limits the application of permanent magnet motor. The sensorless control technology is an effective way to solve the above-mentioned problem. Firstly, the sensorless control techniques of permanent magnet motor are classified. The sensorless control techniques of permanent magnet motor for rotor initial position, zero-low speed range, medium-high speed range and full speed range are deeply described and compared. Finally, the development trend of sensorless control technology of permanent magnet traction motor is prospected.

scholarly journals Sensorless PMSM Drive Inductance Estimation Based on a Data-Driven Approach

Electronics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 791
Author(s):  
Gwangmin Park ◽  
Gyeongil Kim ◽  
Bon-Gwan Gu
Keyword(s):  
Estimation Error ◽  
Position Estimation ◽  
Estimation Accuracy ◽  
Speed Estimation ◽  
Load Torque ◽  
Periodic Load ◽  
Rotor Position ◽  
Speed Error ◽  
Rotor Position Estimation ◽  
Sensorless Drive

In the permanent magnet synchronous motor (PMSM) sensorless drive method, motor inductance is a decisive parameter for rotor position estimation. Due to core magnetic saturation, the motor current easily invokes inductance variation and degrades rotor position estimation accuracy. For a constant load torque, saturated inductance and inductance error in the sensorless drive method are constant. Inductance error results in constant rotor position estimation error and minor degradations, such as less optimal torque current, but no speed estimation error. For a periodic load torque, the inductance parameter error periodically fluctuates and, as a result, the position estimation error and speed error also periodically fluctuate. Periodic speed error makes speed regulation and load torque compensation especially difficult. This paper presents an inductance parameter estimator based on polynomial neural network (PNN) machine learning for PMSM sensorless drive with a period load torque compensator. By applying an inductance estimator, we also proposed a magnetic saturation compensation method to minimize periodic speed fluctuation. Simulation and experiments were conducted to validate the proposed method by confirming improved position and speed estimation accuracy and reduced system vibration against periodic load torque.

scholarly journals Sensorless rotor position estimation of PMSM for low and high rotor speed

2021 ◽  
Vol 9 (2) ◽  
Author(s):  
Ahmed G. Abo-Khalil ◽  
◽  
Keyword(s):  
Sensorless Control ◽  
Estimation Error ◽  
Permanent Magnet Synchronous Motor ◽  
Position Estimation ◽  
Control Technique ◽  
Rotor Speed ◽  
Position Information ◽  
Rotor Position ◽  
Current Controller ◽  
Rotor Position Estimation

In this paper, a sensorless permanent magnet synchronous motor (PMSM) drive was presented based on calculating the back EMF using the reference stator voltages, which are the output of the d-axis current controller, which includes information about the rotor position. Sensorless control estimates the position information necessary for vector control of the motor without using position sensor or encoder. This can provide effects such as increased system reliability and cost and volume reduction. The back EMFs are calculated in a new coordinate based on the estimated speed to minimize the rotor speed estimation error. The estimated rotor position and rotor speed may fail to track the real rotor position and real rotor speed in extremely low speed since the position error can be amplified from the current controller output voltage, and this may cause the instability problems of tracking controller. So, a compensator has been added to the detector to overcome this disadvantage. In order to verify the validity of the proposed sensorless control technique, an experiment was performed on the PMSM, and the results showed fast-dynamic response, low ripples in motor’s currents, and good performance in tracking speed and power references.

Observer Based Speed Control of PMSM Servo Systems

2011 ◽  
Vol 121-126 ◽  
pp. 3376-3380
Author(s):  
R.N. Huang ◽  
Cheng Song ◽  
Yun Jiang Lou
Keyword(s):  
Kalman Filter ◽  
State Observer ◽  
Detection Accuracy ◽  
Electromagnetic Torque ◽  
Load Torque ◽  
Servo Systems ◽  
Position Information ◽  
Simulation Results ◽  
Instantaneous Speed ◽  
Order State

A speed observer which is consisted of the full order state observer and Kalman filter was designed to estimate instantaneous speed in this paper. It utilized full order state observer to obtain load torque and position information, and combining with electromagnetic torque as the input of Kalman filter. Simulation results show that this method can improve the speed detection accuracy of the PMSM servo system.

Novel Compensation Method to Reduce Rotor Position Estimation Error and Torque Reduction in Signal Injection Based PMSM Drives

2017 ◽  
Vol 8 (2) ◽  
pp. 548
Author(s):  
Ravikumar Setty Allampalli ◽  
PurnaPrajna R Mangsuli ◽  
Kishore Chatterjee
Keyword(s):  
Estimation Error ◽  
Position Estimation ◽  
Estimation Accuracy ◽  
Stator Winding ◽  
High Frequency Signal ◽  
Position Information ◽  
Rotor Position ◽  
Injection Techniques ◽  
Signal Injection ◽  
Rotor Position Estimation

High frequency signal injection techniques are widely used to extract rotor position information from low speed to stand still. Accuracy of estimated rotor position is decreased when stator winding resistance is neglected. Position estimation error also results in output Torque reduction. Parasitic resistance of stator winding causes significant position estimation error <br /> and Torque reduction, if not compensated. Signal injection techniques developed in the literature does not provide detailed analysis and compensation methods to improve rotor position estimation of PMS Motors, where stator winding resistance cannot be neglected. This work analyzes the stator winding resistance effect on position estimation accuracy and proposes novel compensation technique to reduce the position estimation error and torque reduction introduced by stator winding resistance. Prototype hardware of a self-sensing PMSM drive is developed. The effectiveness of the proposed method is verified with the MATLAB/Simulink simulations and experimental results on a prototype self-sensing PMSM drive.

scholarly journals ANALYSIS AND SIMULATION STUDIES FOR THE ESTIMATION OF ROTOR POSITION IN SENSORLESS BLDC

2014 ◽  
pp. 208-212
Author(s):  
NEETHI S. PILLAI ◽  
SALITHA K ◽  
CHIKKU ABRAHAM
Keyword(s):  
Dc Motor ◽  
Position Estimation ◽  
Brushless Dc Motor ◽  
Stable Operation ◽  
Simple Method ◽  
Position Information ◽  
Rotor Position ◽  
Brushless Dc ◽  
Simple Detection ◽  
Rotor Position Estimation

Initial rotor position information is essential for brushless dc motor in order to ensure its stable operation. A simple method for determining the initial rotor position of a sensor less brushless dc motor at standstill is discussed in the paper. The principle behind the rotor position estimation is based on simple detection and comparison of phase voltages and dc link current responses thus relating it with stator inductances. The advantage of this method of estimation of rotor position is that it requires only three voltage pulse injection, and a resolution of 30o is achieved. Moreover no other parameters of the machine are required. The effectiveness of the method is validated by simulation results in Matlab Simulink platform.

Research and Develop on Static Frequency Converter of Pumped Storage Power Plant

2012 ◽  
Vol 608-609 ◽  
pp. 1120-1126 ◽  
Author(s):  
De Shun Wang ◽  
Bo Yang ◽  
Lian Tao Ji
Keyword(s):  
Power Plant ◽  
Control Strategy ◽  
Large Scale ◽  
Frequency Converter ◽  
Position Estimation ◽  
Position Sensor ◽  
Storage Unit ◽  
Rotor Position ◽  
Start Up ◽  
Pumped Storage

A static frequency converter start-up control strategy for pumped-storage power unit is presented. And rotor position detecting without position sensor is realized according to voltage and magnetism equations of ideal synchronous motor mathematics model. The mechanism and implementation method of initial rotor position determination and rotor position estimation under low frequency without position sensor are expounded and validated by simulations. Based on the mentioned control strategy, first set of a static frequency converter start-up device in China for large-scale pumped-storage unit is developed, which is applied to start-up control test in the 90 MW generator/motor of Panjiakou Pumped-storage Power Plant. Test results show that rotor position detecting, pulse commutation, natural commutation, and unit synchronous procedure control of static start-up are all proved. The outcomes have been applied in running equipment, which proves the feasibility of mentioned method.

scholarly journals Performance Analysis of a Full Order Sensorless Control Adaptive Observer for Doubly-Fed Induction Generator in Grid Connected Operation

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1254
Author(s):  
Gianluca Brando ◽  
Adolfo Dannier ◽  
Ivan Spina
Keyword(s):  
Sensorless Control ◽  
Estimation Error ◽  
Position Estimation ◽  
Adaptive Observer ◽  
Induction Generator ◽  
Doubly Fed Induction Generator ◽  
Rotor Position ◽  
Stator Flux ◽  
Doubly Fed ◽  
Rotor Position Estimation

This paper focuses on the performance analysis of a sensorless control for a Doubly Fed Induction Generator (DFIG) in grid-connected operation for turbine-based wind generation systems. With reference to a conventional stator flux based Field Oriented Control (FOC), a full-order adaptive observer is implemented and a criterion to calculate the observer gain matrix is provided. The observer provides the estimated stator flux and an estimation of the rotor position is also obtained through the measurements of stator and rotor phase currents. Due to parameter inaccuracy, the rotor position estimation is affected by an error. As a novelty of the discussed approach, the rotor position estimation error is considered as an additional machine parameter, and an error tracking procedure is envisioned in order to track the DFIG rotor position with better accuracy. In particular, an adaptive law based on the Lyapunov theory is implemented for the tracking of the rotor position estimation error, and a current injection strategy is developed in order to ensure the necessary tracking sensitivity around zero rotor voltages. The roughly evaluated rotor position can be corrected by means of the tracked rotor position estimation error, so that the corrected rotor position is sent to the FOC for the necessary rotating coordinate transformation. An extensive experimental analysis is carried out on an 11 kW, 4 poles, 400 V/50 Hz induction machine testifying the quality of the sensorless control.

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