In-wheel motor system

Patent metadata

Field	Value
Publication number	US-2018111473-A2
Application number	US-201515123731-A
Country	US
Kind code	A2
Filing date	Feb 16, 2015
Priority date	Mar 7, 2014
Publication date	Apr 26, 2018
Grant date	—

Abstract

An in-wheel motor system can drive an in-wheel motor stably, and also allows power feeding from the road surface, even when transmission and reception coils are misaligned. An in-wheel motor system (1) includes a power transmitter (100) that utilizes a resonance phenomenon using a magnetic field. The power transmitter (100) transmits power (P) wirelessly from the vehicle body to an in-wheel motor (10) mounted in a wheel. The in-wheel motor system (1) may also include a communication interface (110) that communicates between the vehicle body and the wheel, and the communication interface (110) may transmit a control signal (CTL) for driving the in-wheel motor.

First claim

1 . An in-wheel motor system comprising:
a power transmitter that utilizes a resonance phenomenon using a magnetic field; wherein the power transmitter transmits power wirelessly from a vehicle body to an in-wheel motor mounted in a wheel.

2 . The in-wheel motor system of claim 1 , further comprising:
a communication interface configured to communicate between the vehicle body and the wheel; wherein the communication interface wirelessly transmits a control signal for driving the in-wheel motor.

3 . The in-wheel motor system of claim 2 , further comprising:
the in-wheel motor; a motor conversion unit configured to convert a first DC voltage into a motor AC voltage that drives the in-wheel motor during powering; a wheel side capacitor configured to smooth the first DC voltage during powering; and a wheel side conversion unit configured to convert a first AC voltage from a wheel side coil into the first DC voltage during powering; wherein the power transmitter comprises:
the wheel side coil, configured to receive wirelessly transmitted power at the wheel side during powering; and
a wheel side resonance capacitor inserted in series between the wheel side conversion unit and the wheel side coil.

4 . The in-wheel motor system of claim 3 , further comprising:
a wheel side controller configured to control, with a first control signal, switching of a switch provided in the wheel side conversion unit; wherein the wheel side controller generates the first control signal so as to control the first DC voltage to be constant.

5 . The in-wheel motor system of claim 4 , wherein the wheel side controller generates the first control signal so that a fundamental power factor of the first AC voltage and a current of the wheel side coil becomes 1.

6 . The in-wheel motor system of claim 4 , wherein with the first control signal, the wheel side controller adjusts a duration that the first AC voltage is zero.

7 . The in-wheel motor system of claim 4 , further comprising:
a wheel side current detector configured to detect a current of the wheel side conversion unit; wherein the wheel side controller detects a sign change in a current of the wheel side coil with the wheel side current detector and generates the first control signal in accordance with information on the detected sign change.

8 . The in-wheel motor system of claim 4 , further comprising:
a voltage detector configured to detect the first DC voltage; wherein the wheel side controller generates the first control signal in accordance with a difference between a value detected by the voltage detector and a target value of the first DC voltage.

9 . The in-wheel motor system of claim 8 , wherein the wheel side controller generates the first control signal in accordance with a number of revolutions and a torque command value of the in-wheel motor.

10 . The in-wheel motor system of claim 3 , further comprising:
a vehicle body side conversion unit configured to convert a second DC voltage from a battery into a second AC voltage and output the second AC voltage to a vehicle body side coil during powering; and the battery; wherein the power transmitter comprises:
the vehicle body side coil, configured to transmit power wirelessly from the vehicle body during powering; and
a vehicle body side resonance capacitor inserted in series between the vehicle body side conversion unit and the vehicle body side coil.

11 . The in-wheel motor system of claim 10 , further comprising:
a vehicle body side controller configured to control, with a second control signal, switching of a switch provided in the vehicle body side conversion unit in accordance with a control signal from the communication interface; wherein the vehicle body side controller generates the second control signal so as to control the first DC voltage to be constant.

12 . The in-wheel motor system of claim 11 , wherein the vehicle body side controller generates the second control signal in accordance with a number of revolutions and a torque command value of the in-wheel motor.

13 . The in-wheel motor system of claim 11 , further comprising:
a vehicle body side current detector configured to detect a current of the vehicle body side conversion unit; wherein the vehicle body side controller generates the second control signal in accordance with a difference between a value detected by the vehicle body side current detector and a target current value corresponding to a number of revolutions and a torque command value of the in-wheel motor.

14 . The in-wheel motor system of claim 10 , wherein during regeneration of the in-wheel motor, the wheel side conversion unit functions as an inverter, and the vehicle body side conversion unit functions as a converter.

Assignees

• Fujimoto Hiroshi
• Imura Takehiro
• Yamamoto Gaku
• Gunji Daisuke
• Sato Motoki
• Univ Tokyo
• Nsk Ltd
• Toyo Electric Mfg Co Ltd

Inventors

• Fujimoto Hiroshi
• Imura Takehiro
• Yamamoto Gaku
• Gunji Daisuke
• Sato Motoki

Classifications

• H02J2105/37

  exchanging power with electric vehicles [EV] or with hybrid electric vehicles [HEV] · CPC title

• H02P6/14

  Electronic commutators · CPC title

• H02P27/08

  with pulse width modulation · CPC title

• H02K7/14

  Structural association with mechanical loads, e.g. with hand-held machine tools or fans (with fan or impeller for cooling the machine H02K9/06) · CPC title

• B60K2007/0038

  the motor moving together with the wheel axle · CPC title