I have been working on a project where so called Lundell alternator plays a crucial role. I haven't got any experience with this device sofar so I have decided to study some literature regarding this device at first. In the Power electronics handbook 3rd edition I have found on page 655 following equation describing alternator output power $P_o = \frac{3\cdot V_o\cdot\sqrt{V_s^2-(4V_o^2/\pi^2)}}{\pi\omega L_s}$, where $V_o$ is the battery voltage, $V_s=k\omega i_f$ is the back-emf voltage magnitude, $\omega$ is the electrical frequency and $L_s$ is the armature leakage inductance.
I have plotted a graph of the function $P_o=P_o(V_o)$ with following parameters $L_s=135\,\mu H$, $k=9\cdot 10^{-3}\, V/(A\cdot rad\cdot s^{-1})$, $i_f=3.6\, A$, $n_m=3000\,min^{-1}$ (mechanical speed of the combustion engine), $p=3$ (number of alternator pole pairs).
From the graph it seems that the alternator power function has "interesting" behavior only for unrealizable (at least in standard vehicle with 12 V lead-acid battery) voltages. Does anybody have any suggestion what could be the main idea behind this function? Thanks for any suggestions.
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