Patent ID: 8080967
Filing Date: 2011-12-20
Classification: B60L,H02K,Y02T

Abstract:
1. A brushless electric machine, comprising: a first drive member having Q permanent magnets where Q is an integer; a second drive member having a plurality of electromagnetic coils, and capable of movement relative to the first drive member; a third drive member disposed to an opposite side from the first drive member with the second drive member therebetween, and having a fixed relative positional relationship with the first drive member; a magnetic sensor, disposed on the second drive member, for detecting relative position of the first and second drive members; and a control circuit for controlling operation of the brushless electric machine, based on an output signal of the magnetic sensor; wherein the third drive member has at locations facing the permanent magnets of the first drive member a plurality of magnetic field strengthening members for strengthening the magnetic field at the location of the second drive member in conjunction with the permanent magnets; wherein the plurality of electromagnetic coils have three coil groups for three phases, each coil group including N electromagnetic coils, where N is an integer equal to or greater than 1; the control circuit drives the three coil groups with a phase difference of 2π/3 such that the three coil groups simultaneously generate a driving force; and the number Q of permanent magnets is equal to the number N of electromagnetic coils of each coil group.