i-Motor Activities

i-Motor Features

  • Constant High Operating Efficiency (At both high and low RPM; without disengaging the motor to change speed)
  • Low Speed – High Torque and High Speed – Low Torque in the same motor
  • Upper Speed Threshold Expanded
  • Regenerative Braking and Regenerative Energy Recovery Systems Simplified
  • Can be used in existing motor designs
  • Reduced cost due to integrated design (all-in-on motor/ constant voltage generator)

i-Motor Features by Type

TypeControl MethodCharacteristics
Type1Mechanical Displacement-Controlling magnetic flux volume without synchronizing with the rotor position.
-Continuous control is possible.
-Can be operated even in insufficient power environment.
Type2Excitation Current
and/or
Magnetization Modification
-Changes in magnetization are possible without synchronizing with the rotor position.
-Easy control of regenerative braking by combined use of excitation current.
-Rotational speed range ensured by power boost.
Type3Excitation Current
and/or
Magnetization Modification
-Magnetization changes by synchronizing to the rotor position.
-Ensures safety of control magnet excitation as compared to SHBE-4.
-Easy control of regenerative braking by combined use of excitation current.
Type4Magnetization Modification-Magnetization changes by synchronizing to the rotor position.
-Can limit to usage environment.
Type52nd Armature Displacement-Control back EMF by displacement of the Second Armature
Can be used in environments with Inadequate power supply.

Intellectual property

i-Motor Corporation have the exclusive license of all patents concerning i-Motor from the patentee and is developing the business.

Patent List(Excerpt)

  • JP4150765/Approved (US 7,567,006/Approved)
  • JP4150779/Approved (US 7,999,432/Approved)
  • JP4403252/Approved (US 8,207,645/Approved)
  • JP4403253/Approved (US 8,242,653/Approved)
  • JP4649625/Approved (US 8,373,325/Approved)
  • JP5265799/Approved (PCT/JP 2013/71888 /Pending)

i-Motor Overview

Structure and problem of existing motor

The motor of "Magnet field magnetic" is main for existing HEV, PHEV and EV.

Thus, the existing motor has problem that "field control range" and "energy efficiency" are limited because the rotor's field magnet is constant.

The solution of i-Motor

i-Motor’s patented technology allows for efficient operation at high and low speeds due to unrestricted control of the motor’s field and back EMF. For example in i-Motor Type5, Control the back EMF by displacement of the second armature, by using armature reaction.

i-Motor Type 5
i-Motor Type 5 prototype

By displacement of the second armature, the efficient operation at high and low speeds is achieved.

The application to EV/ HEV

Energy loss in electric vehicles should be limited to various points of friction, the key to this is improving total energy efficiency including during regenerative braking.
Currently, magnet field motors are mainstream, however, their field control range and energy efficiency are limited; especially when it comes to regenerative braking (braking power control and energy recovery efficiency).


This invention uses variable permanent magnets for field control:

  • Can be added to existing motor structures.
  • Field strengthening and weakening control that is independent of drive current.


This Leads to the Following Features:

  • High Energy Efficiency (Including Regeneration)
  • Optimal Control at all Speeds
  • Low Eddy Current Loss
  • Low speed/High Torque
  • Optimal Control of Torque/Current Variations
  • Expanded High Speed Threshold


The Following Features are Specific to EV/HEV:

  • An all-in-one Field Control Motor/ Voltage Control Generator structure.
  • At no load (when coasting) flux leakage from the rotor is nearly zero so drag on the motor (eddy current loss) is limited.


Applications include:

  • Variable motors and generators for EV / HEV, Trains, Wind Power Generation, Air Conditioners, etc.