Quasi bipolar topology for brushless motors

Abstract

A circuit 100 for a five phase DC brushless motor includes a first coil A and a first primary switch S1 for controlling current through the first coil; a second coil B and a second primary switch S3 for controlling current through the second coil; a third coil C and a third primary switch S5 for controlling current through the third coil; a fourth coil D and a fourth primary switch S7 for controlling current through the fourth coil; a fifth coil E and a fifth primary switch S9 for controlling current through the fifth coil. The first coil A is arranged to have a polarity of back EMF opposite of that of the third coil C; the second coil B is arranged to have a polarity of back EMF opposite of that of the fourth coil D; the third coil C is arranged to have a polarity of back EMF opposite of that of the fifth coil E, the fourth coil D is arranged to have a polarity of back EMF opposite of that of the first coil A; and the fifth coil E is arranged to have a polarity of back EMF opposite of that of the second coil B. The circuit further includes a first freewheeling current conducting switch S2 and a diode A between the first coil and the third coil; a second freewheeling current conducting switch S4 and a diode between the second coil and the fourth coil; a third freewheeling current conducing switch S6 and a diode between the third coil and the fifth coil; a fourth freewheeling current conducting switch S8 and a diode between the fourth coil and the first coil, and a fifth freewheeling current conducting switch S10 and diode between the fifth coil and the second coil.

Dependencies are inferred from the claim text.