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This motor adopted a salient pole type surface permanent magnet rotor, which enables it both to produce reluctance torque and to minimize the use of magnets. The inductance value is set at the limit value enabling output at the maximum rotor speed, which suppresses field-weakening current. The utilization of the magnets enables continuous operation at the maximum rotor speed by suppressing eddy current loss by means of magnet surface insulation and magnet segmentation. Strength reliability at high rotor speeds has been assured by applying the Weibull-theory as a method of evaluating the strength of magnets.

The Intelligent Power Unit (IPU) of the Integrated Motor Assist (IMA) system was developed with the dual objectives of increased output and reduced size. To realize miniaturization and to reduce energy losses, fine patterning of IGBT chips in the inverter was conducted, transfer mold power modules were used, and film capacitors were integrated in the unit. Parts integration by digital control was performed in the 12V DC-DC converter. The internal resistance was reduced and the output increased of the IMA battery by changing the construction of the current collector and increasing the length of the electrodes. The battery box was made of a new design enabling easy assembly. The cooling system construction of the box was modified, and the pitch between the modules was reduced, enabling the battery box to be made more compact.