Wireless power supply system and power transmission device

• US 9,845,019 B2
• Filed: 02/25/2014
• Issued: 12/19/2017
• Est. Priority Date: 02/25/2014
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Okamoto, Tomofumi
• Primary Examiner(s): Barnie, Rexford
• Assistant Examiner(s): Shiao, David
• Application Number:
  US15/118,947
• Publication Number:
  US 20160355095A1
• Time in Patent Office: 1,393 Days
• CPC Class Codes: B60L 2210/10 DC to DC converters
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: B60L 53/12 Inductive energy transfer
• CPC Class Codes: B60L 53/126 Methods for pairing a vehicle and a charging station, e.g. establishing a one-to-one relation between a wireless power transmitter and a wireless power receiver
• CPC Class Codes: B60L 53/305 Communication interfaces
• CPC Class Codes: B60L 53/65 involving identification of vehicles or their battery types
• CPC Class Codes: H02J 2310/48 for electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H02J 7/00304 Overcurrent protection
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles
• CPC Class Codes: Y02T 90/16 Information or communication technologies improving the operation of electric vehicles
• CPC Class Codes: Y02T 90/167 : Systems integrating technologies related to power network operation and communication or information technologies for supporting the interoperability of electric or hybrid vehicles, i.e. smartgrids as interface for battery charging of electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: Y04S 30/14 : Details associated with the interoperability, e.g. vehicle recognition, authentication, identification or billing

Abstract

A wireless power supply system includes a power transmission device having a power transmission coil and a power receiving device having a power receiving coil. The power receiving device calculates a first efficiency based on a transmission power command value and the electric power supplied to the battery. The power transmission device calculates a second efficiency based on a phase difference between a voltage and a current supplied to the power transmission coil. The power transmission device controls electric power supplied to the power transmission coil according to the transmission power command value, and regulate the electric power supplied to the power transmission coil when the first efficiency falls to a predetermined first threshold efficiency or less or when the second efficiency falls to a predetermined second threshold efficiency or less.

Claims

1. A wireless power supply system comprising a power transmission device provided on a ground side and having a power transmission coil, and a power receiving device provided in a vehicle and having a power receiving coil, the power transmission coil transmitting electric power to the power receiving coil via a wireless connection, so as to supply the electric power to an electrical load installed in the power receiving device, the power receiving device including:

a first efficiency calculator configured to calculate a first efficiency based on a transmission power command value and the electric power supplied to the electrical load; and

a switching controller configured to stop supplying the electric power received by the power receiving coil to the electrical load when the first efficiency falls to a predetermined first threshold efficiency or less,

the power transmission device including;

a second efficiency calculator configured to calculate a second efficiency based on a phase difference between a voltage and a current supplied to the power transmission coil; and

power controller configured to control electric power supplied to the power transmission coil according to the transmission power command value, and regulate the electric power supplied to the power transmission coil when the second efficiency falls to a predetermined second threshold efficiency or less when electric power supplied to the electrical load is stopped by the switching controller.

2. The wireless power supply system according to claim 1, wherein the power controller corrects the transmission power command value based on the first efficiency when the power controller obtains the first efficiency, and corrects the transmission power command value based on the second efficiency when the second efficiency calculator calculates the second efficiency.

3. The wireless power supply system according to claim 2, wherein:

the power transmission device includes a power transmission-side communication unit that communicates with the power receiving device, and the power receiving device includes a power receiving-side communication unit that communicates with the power transmission device;

the first efficiency calculator is provided in the power receiving device, and calculates the first efficiency based on a voltage and a current supplied to the electrical load;

the power receiving-side communication unit transmits the first efficiency to the power transmission-side communication unit in a second cycle; and

the second efficiency calculator calculates the second efficiency in a first cycle shorter than the second cycle.