Control With Optimal Energy Regeneration in Robot Manipulators Driven by Brushless DC Motors

2018 ◽  
Author(s):  
Amin Ghorbanpour ◽  
Hanz Richter
Keyword(s):  
Motion Control ◽  
Pulse Width Modulation ◽  
Inverse Dynamics ◽  
Robot Manipulators ◽  
Optimization Approach ◽  
Brushless Dc Motors ◽  
Energy Regeneration ◽  
Brushless Dc ◽  
Optimal Current ◽  
Regenerative Energy

In this work, simultaneous energy regeneration and motion control for robot manipulators with brushless motors is considered. The robot has a number of semi-active joints connected to ultracapacitors, while the remaining joints are fully-active, powered from constant-voltage power supplies. A three-phase inverter is used to apply voltage to each motor, and the space vector pulse width modulation technique is used to generate voltage commands for the inverter. A PI controller is used to generate voltage commands for the inverter based on reference currents. A method is developed to obtain actual torque based on the desired torque generated by a virtual controller, which can be any suitable robot motion control algorithm, for instance inverse dynamics. A novel optimization approach is used to generate reference currents that maximize the amount of regenerative energy stored in the ultracapacitor and motor inductance subject to the torque demanded by the virtual controller. An explicit solution is found for the optimal current references and it is shown that the well-known choice of a zero direct current component in the direct-quadrature frame is sub-optimal relative to our energy optimization objective. A simulation using a 2-link planar manipulator with one active and one semi-active joint is used to illustrate the results.

scholarly journals Torque Ripple Reduction in Brushless DC Motor by Using SPWM and SVPWM Techniques

2018 ◽  
Vol 7 (4.24) ◽  
pp. 71
Author(s):  
Ch.N. Narasimha Rao ◽  
G. Durga Sukumar ◽  
R. Vinod Kumar
Keyword(s):  
Pulse Width Modulation ◽  
Control Method ◽  
Fuzzy Controller ◽  
Torque Ripple ◽  
Bldc Motor ◽  
Space Vector Pwm ◽  
Space Vector ◽  
Brushless Dc Motors ◽  
Frequency Space ◽  
Brushless Dc

Brushless DC motors have the large applications because of its easiest control system and the highest efficiency. Industrial BLDC motor drives suffers from the ripples in the torque, due to which motor has more noise, vibrations and less efficient. To reduce the ripple, the Space Vector PWM (SVPWM) and Sinusoidal PWM are implemented in BLDC drive. The Pulse Width Modulation (PWM) controls the converter output voltage and frequency. Space Vector PWM (SVPWM)and Sinusoidal PWM are the best techniques used in industries because its easy design. Space Vector PWM control method is implemented and it overcomes the disadvantages in PWM such as losses in switching of the converter, output harmonic content& provides better DC-bus voltages. The torque ripples are also reduced in SVPWM method compared to SPWM method. In this paper BLDC motor with a fuzzy controller is presented and the comparison in performance of SVPWM &SPWM methods presented. The SVPWM makes the drive has less ripple in torque& noiseless operation. The Matlab/Simulink models of SVPWM and SPWM method with fuzzy controlled BLDC motor also presented.

Torque Ripple Suppression of Brushless DC Motors with Non-Ideal Back EMF for EPS Applications

2011 ◽  
Vol 201-203 ◽  
pp. 1198-1205 ◽  
Author(s):  
Xue Feng Zhang ◽  
Xue Wu Ji ◽  
Feng Gao
Keyword(s):  
High Performance ◽  
Pulse Width Modulation ◽  
Control Method ◽  
Torque Ripple ◽  
Brushless Dc Motors ◽  
Brushless Dc ◽  
Power Steering ◽  
Dc Motors ◽  
Commutation Torque Ripple ◽  
Type Motor

The torque ripple of brushless dc (BLDC) motors at low rotation speeds is prominent, while in the majority of working time of the automotive electric power steering (EPS) system, the steering rate is low and the assistant motor runs at low rotation speeds. Therefore, to develop a high-performance EPS system with a BLDC motor, the problem of torque ripple at low rotation speeds must be solved. Otherwise, the steering feel will not be smooth. This paper proposed an algorithm based on BLDC motors’ essential torque formula combined with the back-EMF (Electromotive Force) waveform coefficient to modify the target current to suppress the torque pulsation effectively. Meanwhile, the commutation process of this type motor is very short. Therefore, the torque coefficient can be regarded as constant during the commutation intervals. A direct pulse-width modulation (PWM) control method considering phase resistances is analyzed with a unipolar PWM scheme to reduce the commutation torque ripple further. Finally, simulations and experiments are conducted to verify the effectiveness of this method.

Recent Challenges and Advances in the Sensorless Commutation of Brushless DC Motors

2020 ◽  
Vol 13 ◽  
Author(s):  
Umesh Kumar Soni ◽  
Ramesh Kumar Tripathi
Keyword(s):  
Initial Position ◽  
Position Estimation ◽  
Current Response ◽  
Flux Linkage ◽  
Brushless Dc Motors ◽  
Position Sensing ◽  
Brushless Dc ◽  
Dc Motors ◽  
Reverse Torque ◽  
Position Detection

Background: Brushless DC motors are highly efficient motors due to its high torque to weight ratio, compact design, high speed operating capability and higher power density. Conventional Hall sensor based rotor position sensing is affected by the heating, vibration, interference and noise. Objective: The innovative, cost effective and easily implementable sensorless techniques are essential in order to achieve high efficiency, reduced current and reduced torque pulsations. Further, a delay free, high load fast startup is also important issue. Methods: In this paper an extensive review of various techniques based on the detection of freewheeling diode current, phase back EMF zero crossoing point detection, back EMF integration method and third harmonic back EMF was done. The study and effect of various PWM strategies on back EMF detection was studied. Later on the sensorless schemes based on flux linkage estimation and flux linkage increment were introduced. The load torque observers, unknown input observers, sliding mode observers, L∞-induced observers, H ∞ - deconvolution filter for back EMF estimation were also reviewed. As the brushless DC motors have no back EMF at starting and for back EMF based commutation a minimum speed is required for sufficient back EMF. Therefore various strategies of open and close-loop reduced current startup have been studied to achieve effective commutation without reverse torque. Initial position detection (IPD) schemes, which are mostly based on saliency and current response to inductance variation, is effective where reverse torque is strictly prohibited. A detailed review of these initial position detection techniques (IPD) has also been presented. Results: The detailed mathematical and graphical analysis has been presented here in order to understand the working of the state-of-art sensorless techniques. Conclusion: The back EMF detection using direct and indirect methods of terminal voltage filtering have the problem of delay and attenuation, PWM noise, freewheeling diode spikes and disturbance in detected back EMFs is a drawback. The parameter detuning, underestimation and overestimation, offset problem, system noise and observer gain variation etc. limit the applicability of observer based technique. Therefore, a more robust and precise position estimation scheme is essential.

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