Figure 1 - uploaded by Noureddine Takorabet
Content may be subject to copyright.
Global circuit representation of a 4 wound field poles and 4 brushes DC motor; relevant parameters of the armature winding.
Source publication
This paper deals with the modeling of the brushed DC motor used as a reinforced starter for a micro-hybrid automotive application. The aim of such a system, also called "stop-start", is to stop a combustion engine when the vehicle pulls to a stop, and to restart it when the driver accelerates. A reinforced starter is able to ensure this new functio...
Contexts in source publication
Context 1
... role of the brushes is to supply armature sections with alternating current so that the field created by the armature is orthogonal to the field created by the coils in order to maximize the magnetic coupling. The general circuit is represented Figure 1. The positions of brushes on the commutator determine the electrical behavior of armature sections. ...
Context 2
... automotive starter applications, brushes shown on Figure 6 are made with two layers of electric resistivity ρ 1 and ρ 2 in order to increase contact resistance at the end of the commutation and thus reduce arc occurring. Figure 4. Equivalent electrical circuit of the armature represented in Figure 1 for the specific position of the brushes on the commutator represented on Figure 2 (the anodic brushes are in contact with the segments number 8-9-18-19 when the cathodic ones are in contact with the segments 3-4-5-13-14). In the following, we propose a measurement method to characterize the electrical contact resistance which is a function of the position θ. ...
Context 3
... voltage drop at the sliding contact is also integrated in our numerical approach by considering a highly resistive thin layer at the contact (ρ 4 ρ 3 ) as showed in Figure 9. The ρ 4 resistivity is chosen to correlate our model with measurements as shown on Figure 10. ...
Context 4
... test bench presented in the previous section allows to determine the equivalent resistance for a given geometry. Figure 10 shows the results of the measurement (blue) and those provided by finite element model (red). ...
Context 5
... main program uses the results of the previous iteration to determine the state of the circuit at the current time and provide the appropriate values of contact resistances and arc voltage. The principle of the algorithm is described in Figure 11. ...
Context 6
... step must be connected to the size of an element in the air gap in order to limit numerical instabilities (in particular for the calculation of electromagnetic torque) due to mesh noise. The mesh description of the entire machine is shown in Figure 12 and in Figure 13 for the air gap. Mesh in the stator must be particularly refined to take into account eddy currents in the solid iron pole shoes. ...
Context 7
... step must be connected to the size of an element in the air gap in order to limit numerical instabilities (in particular for the calculation of electromagnetic torque) due to mesh noise. The mesh description of the entire machine is shown in Figure 12 and in Figure 13 for the air gap. Mesh in the stator must be particularly refined to take into account eddy currents in the solid iron pole shoes. ...
Context 8
... measurements of armature current during rotation in brushed DC motors are often made [8,10]. In most cases, it concerns high voltage/low current motor so that two slip rings with brushes are used to exit one coil current while the armature is rotating as illustrated on Figure 15. Current can thus be measured thanks to a Hall effect sensor. ...
Context 9
... the others coils of the armature are also designed (with a smaller inner copper diameter) to have an armature winding electrically balanced (same resistance per section). The developed armature also enables the measurement of the potential of the two segments (called V 1 and V 2 ) located at the bottom of the considered coil as shown on Figure 15. Finally, the device allows the knowledge of all of the internal waveforms (coil current and voltage, Brush-segment voltage drop) characterizing the commutation phenomena. ...
Context 10
... prototype, shown on Figure 16, is driven at constant speed with an external motor and supplied by a 12 V voltage source. The brushes and the armature used on the device have been run in before the measurements in order to have a good shape of the brushes and a good commutator film quality. ...
Context 11
... of the previous model can be compared to measurements thanks to the specific test bench. We are going to compare coil current waveforms (Figure 17) and Brush-segment voltage drop waveforms (Figure 18) for one operating point (6000 rpm) and a negative brush shift angle (−5 mechanical degrees) during one mechanical revolution. ...
Context 12
... of the previous model can be compared to measurements thanks to the specific test bench. We are going to compare coil current waveforms (Figure 17) and Brush-segment voltage drop waveforms (Figure 18) for one operating point (6000 rpm) and a negative brush shift angle (−5 mechanical degrees) during one mechanical revolution. ...
Context 13
... first observe that both waveforms are relatively close to measurements especially in terms of amplitude. However, we can notice that the calculated current waveform (Figure 17) does not fit to the measured one during the commutation process. The model predicts a reverse phenomenon of the current appearing approximately at the middle of the commutation which has not been observed at all in practice. ...
Context 14
... model predicts a reverse phenomenon of the current appearing approximately at the middle of the commutation which has not been observed at all in practice. This reverse phenomenon corresponds to when the current that flows in the contact (Figure 19) is negative. It means that the purely resistive model used does not fit here because the brush to segment current is not constant at all during the commutation process as assuming previously. ...
Citations
... In the case of brushed DC machines, the most common way to implement the commutator system consists in including the latter in the electric circuit. 8 Indeed, with an electronic point of view, the commutator can be easily modeled as a group of switches creating a slot signal. ...
Nowadays, research on electromagnetic devices increasingly focuses on multiphysics three‐dimensional complex systems. However, this kind of simulations require huge computational resources and consequently very high CPU time. Ristagno et al. proposed a level‐set based method allowing meshing step savings in any iterative processes (as movement modeling or optimization processes). The level‐set method lies in implicit description of moving fronts as described in the study by Osher et al. (1988). Inspired by Räisänen et al., all physical parameters (material properties, supply or armature movement) are implemented by projection of mathematical functions. In this paper, the authors proposes to study and design a new kind of mechanical commutator for DC machines thanks to this coupled method. Indeed, there is a renewed interest in DC machines because they can be suitable for small mobilities. To be noted, small mobility concerns all kind of vehicles (2 wheels–4 wheels–autonomous vehicles such as drones) that have speeds below 50 km/h. However, specifications for traction applications are difficult to achieve for such a rustic machine and requires some modifications. That is why, inspired by usual synchronous machine, the commutator has been redesigned to obtain expected theoretically signal waveform. Furthermore, numerical coupled simulations have been used to design both machine and supply simultaneously. This work has led to the manufacture of a proof of concept and preliminary results are very promising.
... The recent study in [6][7] illustrates the critical issues like degradation of brushes, reduction condition of contact resistance uncertainty in view of magnitude of current, ambient temperature and rotating speed. In the study [8] a method has been proposed for efficiently computing a brushed DC motor circuit model which accommodates the brush-segment contact resistance. In the recent research [9][10] the speed estimation in view of armature resistance variation with respect to thermal effect has been discussed. ...
In view of recent advancement in consumer and industrial devices, sensorless estimation has been accepted and applied widely. Speed measurement of brushed permanent magnet direct current (PMDC) motor is an integral part of controlling velocity servomechanism. The model-based observer design is simply achieved by following pole placement technique; however, in the parameter varying environment, the issue of robust performance has to be accounted for. The LMI technique-based observer is supposed to accommodate parameter variation but with relatively complex configuration. In this paper, a thorough performance comparison between rotor speed observer designs of armature controlled DC motor using pole placement technique with that of the LMI technique has been accomplished. The results generated through MATLAB simulation were interesting in the perspective of speed and current observation error.
... Zespół ten prowadzi badania nad możliwością wykorzystania zjawiska Halla do opracowania metody, pozwala- jącej na ocenę eksploatacyjnego zużycia rozrusznika w środkach transportu. Zagadnieniami tymi zajmowali się naukowcy w Indiach [150][151][152][153] oraz naukowcy z Francji [5,[135][136][137]. Badania związane z analizą pola magnetycznego prowadzone są przez Politechnikę Warszawską [191,192] oraz naukowców z Węgier [17, 84-86, 132, 207] i Chin [103,111,227]. ...
This book gathers selected research papers presented at the International Conference on Recent Trends in Machine Learning, IOT, Smart Cities & Applications (ICMISC 2020), held on 29–30 March 2020 at CMR Institute of Technology, Hyderabad, Telangana, India. Discussing current trends in machine learning, Internet of things, and smart cities applications, with a focus on multi-disciplinary research in the area of artificial intelligence and cyber-physical systems, this book is a valuable resource for scientists, research scholars and PG students wanting formulate their research ideas and find the future directions in these areas. Further, it serves as a reference work anyone wishing to understand the latest technologies used by practicing engineers around the globe.
A typical approach for “sensorless” angle or speed measurement of DC machines is to evaluate periodic oscillations in the electrical motor signals – mainly the current signal – which is also known as ripple counting. This method is very susceptible to counting errors due to different waveforms caused by various influences. In this paper the steady-state current waveforms of a small DC machine are investigated to identify the causes leading to incorrect counting results. The focus is on production tolerances and changes over the service life of the motor. This is done both by experimental and simulative investigations and analysis of the signals in the time and frequency domain. For the simulative investigation much attention is paid to a suitable modeling for this particular task and parameter variations are performed to separate the influences on the current signal. The goal is a better understanding of the different waveforms and their causes as a basis for the development of future error-free counting algorithms.
In the new generation of “Stop & Start” starters, a DC series motor with high power density is used. In this application, non-symmetrical machines are used due to the single wave winding in brushed motors. The saturation of the iron core in this application reaches a really high level. Moreover, armature reaction in DC machine with a large stator pole spans makes this phenomenon even more enhanced. All these criteria lead to model the whole machine in highly saturated conditions which is time consuming. In this paper, a fast reluctance network (RN) model for an equivalent machine is proposed. It takes into account the armature reaction in high saturation conditions. It also allows a good accuracy and permits us to show the relevance of taking into account this phenomenon in torque calculation. This model is validated by a finite element (FE) method in many operating points, and by a statistical approach. It shows high robustness and low computation time. Finally, an optimization procedure using this reluctance network model and FE is presented in order to show the accuracy of the RN compared to FE model.
This paper provides a review of several original improvements of 6-ferrite 12-V brushed DC starters, based on unconventional uses of Halbach arrays. Electromagnetic behaviors are firstly analyzed, especially when specific to this saturated high-current automotive application; hence the armature magnetic reaction and its link to commutation. After explaining which properties of Halbach arrays can be exploited, each novel design is detailed. Prototypes have been built and tested, so all three variants of motors are validated, whatever the type of material implemented, sintered or bonded magnets, even combined with an ironless armature instead of the usual slotted and laminated one. The proposals appear more expensive, but occur to be a great help to applications, showing enhancements in dynamic performance and brush durability, as two mandatory key features for modern starting systems.
