Lundell generator (alternator). Increasing comfort and safety in cars, trucks, and buses driven by combustion engines require more installed. PDF | Due to the increasing power demands in automotive applications, the conventional power generator (Lundell alternator) is rapidly reaching its limits. Abstract—Thermal analysis of Lundell alternators used in automobiles is presented. An analytical thermal model for Lun- dell alternators is proposed, and .
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Typical phase voltage and current waveforms at and rpm are shown in Figure 5a and Figure 5b, with rectifier and resistive load no battery. The first commercial mild hybrid electrical vehicle, launched inmakes lhndell of the Lundell machine as a starter generator. Many alternatives are being considered to replace the Lundell alternator such as the salient pole machines, however they require large investments in manufacturing infrastructure.
Analysis of Electric Machinery.
Alternator (automotive) – Wikipedia
Until in the early s, automobiles used a DC generator called dynamo. The new lap windings have the same coil pitch as the original alternator and 12 conductors per slot.
For the eight-diode rectifier, the phase voltage third harmonic in the phase current occurs. Usually six diodes in a full-bridge configuration are used to rectify the output current.
Reduced Lundell (claw-pole) alternator with an external voltage regulator – Simulink
Efficiency of automotive alternators is limited by fan cooling lundsll, bearing loss, iron loss, copper loss, and the voltage drop in the diode bridges.
In the current air cooled alternators, one or two fans are used for convection cooling.
Stator winding resistance, Rs — Resistance scalar. Coulomb friction, Kc — Friction scalar. To provide direct current with low ripplea polyphase winding is used and the pole-pieces of the rotor are shaped claw-pole. All Examples Functions Blocks More. Alternator efficiency Generally, Lundell alternators are characterized by low efficiency due to important mechanical, copper, and magnetic losses.
One solution is to divide each phase winding in several coil groups and to modify the winding configuration by using several switches.
This chapter discusses the performance of the conventional automotive alternators and various modeling methods for the simulation of the alternator-rectifiers. Winding reconfiguration Winding reconfiguration is an interesting approach to improve output power, efficiency and satisfy idle current specifications.
Edited by Joao Carmo.
Current ratings are normalized with respect to I SC. A voltage sensor and regulator command the DC—DC converter to keep the voltage of the battery in a certain interval roughly 12 to 17 Vdc, for 14 Vdc batteries at all times, and provides overvoltage and overcurrent protection.
Influence of the number of turns on the performance The number of turns in the stator winding has a significant effect on the output performances of an alternator connected to a Conventional Diode Rectifier CDR and a battery. The armature phase resistance is measured at the rated temperature rise. Another way is to rewind the alternator with a lower number of turns and to replace the conventional diode rectifier by an active PWM rectifier.
In the alternator mode, the converter operates as a synchronous rectifier. The excitation coil is surrounded by two solid iron pole pieces, or claw poles, and is fed via a pair of slip rings and two carbon brushes. Also note that for non-interleaved structures using PWM, the rms value of the ripple component of the output current is about 10 times more significant than with other structures. In case of controlled rectifiers, the armature reaction can have a magnetizing effect at low speeds depending on the power angle.
The results show that the modification of the number of turns and replacing the diode rectifier with other electronic converters could significantly increase the output current and the efficiency. Note that the double-winding configuration provides higher output current when the speed is greater than rpm but the current is reduced at low-speed. Wikimedia Commons has media related to Automobile alternators. Martins and Philippe Viarouge Submitted: An efficient cooling method is necessary to limit the temperature in the motor beyond the permissible limits a junction temperature of C for the diodes and the stator winding.
Experimental current waveforms are shown in fig. First, we present the conventional automotive generating system, its performance and the limitation of modelling methods. Torque is measured by a rotating torque sensor and a strain gauge.
Fast diode rms current IFD.
Power Electronic Solutions to Improve the Performance of Lundell Automotive Alternators
The Model T incorporated its magneto into the engine flywheel. Professional in AutoCAD programming. If bidirectional power flow is not required, the three single-phase Lundelll structure shown in fig. The stator current and two diode drops reduce the stator voltage.
This can be partially explained by lower ESR losses in the output capacitor.
A 3-phase synchronous machine can be modeled by its equivalent circuit as shown in fig. Current filter bandwidth, Fc — Bandwidth scalar. It also shows the output current curves obtained with original and rewound alternators connected to a conventional diode rectifier. Experimental current waveforms for: The excitation circuit is disconnected when the ICE is shut down, to save in battery life and in fuel consumption.
Electrical modeling of wlternator machine A 3-phase synchronous machine can lunxell modeled by its equivalent circuit as shown in fig. The smaller, enclosed fans produce less noise, particularly at higher machine speeds. These fans add to the alternator aerodynamic losses and are also responsible for an important part of the alternator audible noise at higher speeds.
How to cite and reference Link to this chapter Copy to clipboard. The average output power and the efficiency are very similar for all the structures connected to a rewound machine since all structures regain the conventional diode rectifying mode during high-speed operation. Alternators have several advantages over direct-current generators dynamos. When the temperature decreases, the battery voltage increases for all states of battery charge.
The stator is composed of a slotted laminated iron core and a three-phase overlapped winding, wye or delta connected.