Wireless in-wheel motor drive and method for optimizing the same
AssigneeCity University of Hong Kong
InventorsXin Chen, Chi Kong Tse
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Abstract
The present invention provides a wireless soft-switching in-wheel motor drive system and a method for realizing the same. The method comprises pre-misaligning the primary winding and the secondary winding of a magnetic coupler of the in-wheel motor drive system for an angular offset such that an input impedance of the resonant compensation network of the in-wheel motor drive system has a short-circuit boundary frequency less than an open-circuit boundary frequency throughout a target misalignment tolerance between the primary winding and the secondary winding. The present invention can ensure soft switching of the in-wheel motor drive system, save system volume, minimize power losses, and achieve high efficiency.
Claims11
A wireless soft-switching in-wheel motor drive system, comprising:
- a vehicle-body side including a vehicle-body-side series resonant capacitor CP;
- a wheel side including a wheel-side series resonant capacitor Cr and a wheel-side parallel resonant capacitor CS;
- and
- a magnetic coupler configured for transferring power from the vehicle-body side to the wheel side under a switching frequency, including:
- a primary winding electrically connected in series to the vehicle-body-side series resonant capacitor CP;
- and
- a secondary winding electrically connected in series to the wheel-side series resonant capacitor Cr and in parallel to the wheel-side parallel resonant capacitor CS;
- wherein:
- a resonant compensation network is formed of the vehicle-body-side series resonant capacitor CP, the wheel-side series resonant capacitor Cr, the wheel-side parallel resonant capacitor CS, a self-inductance Lp of the primary winding, a self-inductance LS of the secondary winding and a mutual inductances M between the primary winding and the secondary winding;
- the primary winding and the secondary winding are pre-misaligned with an angular offset such that an input impedance of the resonant compensation network has a short-circuit boundary frequency ωsc3 less than an open-circuit boundary frequency ωop2 throughout a target misalignment tolerance between the primary winding and the secondary winding;
- and
- the switching frequency is selected between the short-circuit boundary frequency and the open-circuit boundary frequency;
- and
- the self-inductances and mutual inductances of the primary winding and the secondary winding are adjusted with virtual parameters such that a difference between the short-circuit boundary frequency ωsc3 and the open-circuit boundary frequency ωop2 is greater than a target soft switching frequency band throughout the target misalignment tolerance and target operational load conditions.
A method for realizing soft switching and optimizing efficiency of a wireless in-wheel motor drive system comprising a vehicle-body side, a wheel side and a magnetic coupler configured for transferring power from the vehicle-body side to the wheel side under a switching frequency;
- the method comprising:
- forming a resonant compensation network by:
- electrically connecting a primary winding of the magnetic coupler n series to a vehicle-body-side series resonant capacitor CP;
- and
- electrically connecting a secondary winding in series to a wheel-side series resonant capacitor Cr and in parallel to a wheel-side parallel resonant capacitor CS;
- pre-misaligning the primary winding and the secondary winding of the magnetic coupler for an angular offset such that an input impedance of the resonant compensation network has a short-circuit boundary frequency ωsc3 less than an open-circuit boundary frequency ωop2 throughout a target misalignment tolerance between the primary winding and the secondary winding;
- selecting the switching frequency to be between the short-circuit boundary frequency and the open-circuit boundary frequency;
- and
- adjusting self-inductances and mutual inductances of the primary winding and the secondary winding with virtual parameters such that a difference between the short-circuit boundary frequency ωsc3 and the open-circuit boundary frequency ωop2 is greater than a target soft switching frequency band throughout the target misalignment tolerance and target operational load conditions.
Dependencies are inferred from the claim text.