theoretical and electromagnetic field analysis in iron bridges
are not given. [10] compares the field weakening performance
between segmented IPMSM and IPMSM with flux barriers
(IPMSMFB). Results show that IPMSMFB have advantages of
high power density and wide CPSR, by increasing the ratio
of q-axis inductance and d-axis inductance, which results in
larger reluctance torque. But segmented IPMSM improve field
weakening capability by further reduce the portion of PM flux
going through the air gap, with the help of iron bridges, as
stated in [7]. Hence, they are essentially two different structures
for better field weakening performance. [11] presents a new
rotor design for higher flux weakening capability by optimizing
the position and size of iron bridges. [12] proposes a effective
design methodology using synthetic d-q flux linkage to improve
both current control and torque performance. Although
prototype machines with high CPSR have been reported in
great deal of literatures, but very few of them study the flux
density variation in iron bridges and air gap with demagnetizing
current, as well as the influence of design parameters, such as
number of segments and the width of iron bridges.