Method of early hard switching detection and protection for inductive power transfer

• US 10,483,836 B2
• Filed: 07/31/2017
• Issued: 11/19/2019
• Est. Priority Date: 07/31/2017
• Status: Active Grant

• Current Assignee: Lear Corporation
• Original Assignee: Lear Corporation
• Inventors: Eggers, Kendall
• Primary Examiner(s): Barnie, Rexford N
• Assistant Examiner(s): Ly, Xuan
• Application Number:
  US15/663,989
• Publication Number:
  US 20190036441A1
• Time in Patent Office: 841 Days
• Field of Search: 307104
• CPC Class Codes: B60L 53/122 Circuits or methods for driving the primary coil, e.g. supplying electric power to the coil
• CPC Class Codes: B60L 53/124 Detection or removal of foreign bodies
• 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: H02J 50/12 of the resonant type
• CPC Class Codes: H02M 1/0058 by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826
• CPC Class Codes: H02M 1/083 for the ignition at the zero crossing of the voltage or the current
• CPC Class Codes: H02M 3/01 Resonant DC/DC converters
• CPC Class Codes: H02M 3/33507 with automatic control of the output voltage or current, e.g. flyback converters H02M3/33561, H02M3/33569 take precedence
• CPC Class Codes: H02M 3/33571 Half-bridge at primary side of an isolation transformer
• CPC Class Codes: H02M 3/33573 Full-bridge at primary side of an isolation transformer

Abstract

An inductive power transfer system includes a power converter and a controller. The power converter includes switches. The controller to switch the switches according to a schedule to cause the power converter to output a voltage and a current to a resonant network. The controller to compare a zero-current crossover point of the current and the schedule to determine whether the zero-current crossover point occurs prior to a scheduled time that one or more of the switches are be switched. The controller to disable the switches from switching when the zero-current crossover point occurs prior to the scheduled time such that the switches do not switch at the scheduled time thereby preventing hard switching of the switches from occurring.

Claims

1. A system for inductive power transfer, the system comprising:

a power converter including a plurality of switches;

a controller programmed with a schedule having scheduled times of when the switches are to be switched for the power converter to output a voltage and a current to a resonant network and the controller knowing the schedule in advance of when the switches are to be switched according to the schedule, the controller to switch the switches according to the schedule to cause the power converter to output the voltage and the current to the resonant network; and

the controller to compare a zero-current crossover point of the current and the schedule to determine whether the zero-current crossover point occurs prior to a scheduled time of the schedule that one or more of the switches are be switched and to disable the switches from switching, at least at the scheduled time, when the zero-current crossover point occurs prior to the scheduled time such that the switches do not switch at the scheduled time thereby preventing hard switching of the switches from occurring.

2. The system of claim 1 wherein:

the controller to confirm that soft switching of the one or more of the switches is occurring when the zero-current crossover point occurs after the scheduled time that the one or more of the switches are switched.

3. The system of claim 1 wherein:

the scheduled time includes a start time that the one or more of the switches are switched on and an end time that the one or more of the switches are switched off.

4. The system of claim 1 wherein:

the power converter includes a full-bridge circuit having four switches.

5. The system of claim 1 wherein:

the power converter includes a half-bridge circuit having two switches.

6. The system of claim 1 wherein:

the switches are transistor switches.

7. The system of claim 1 wherein:

the switches are MOSFET switches.

8. A method for inductive power transfer for use with a power converter including a plurality of switches, the method comprising:

programming a controller with a schedule having scheduled times of when the switches are to be switched for the power converter to output a voltage and a current to a resonant network such that the controller knows the schedule in advance of when the switches are to be switched according to the schedule;

switching, by the controller, the switches of the power converter according to the schedule;

comparing a zero-current crossover point of the current and the schedule and detecting that the zero-current crossover point occurs prior to a scheduled time of the schedule that one or more of the switches are be switched; and

disabling the switches from switching, at least at the scheduled time, in response to the zero-current crossover point occurring prior to the scheduled time such that the switches do not switch at the scheduled time thereby preventing hard switching of the switches from occurring.

9. The method of claim 8 further comprising:

confirming that soft switching of the one or more of the switches is occurring when the zero-current crossover point occurs after the scheduled time that the one or more of the switches are switched.

10. The method of claim 8 wherein:

the scheduled time includes a start time that the one or more of the switches are switched on and an end time that the one or more of the switches are switched off.