Method of and apparatus for generating an adjustable reactance

• US 9,754,717 B2
• Filed: 05/10/2013
• Issued: 09/05/2017
• Est. Priority Date: 05/11/2012
• Status: Active Grant

• Current Assignee: InductEV Inc.
• Original Assignee: Momentum Dynamics Corporation
• Inventors: Long, Bruce Richard, Daga, Andrew William, Hackman, Daniel S.
• Primary Examiner(s): Barnie, Rexford
• Assistant Examiner(s): Mourad, Rasem
• Application Number:
  US13/891,917
• Publication Number:
  US 20130300209A1
• Time in Patent Office: 1,579 Days
• Field of Search: 307104
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
• 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 90/14 Plug-in electric vehicles

Abstract

A method for adjusting reactance includes an adjustable reactance generator including a comparator receiving an input sinusoidal waveform and outputting a square wave that retains the frequency and phase of the applied sinusoidal waveform. The reactance adjustment is generated using a power switching circuit that receives the square wave from the comparator as a control signal and outputs a square wave that retains the frequency and phase of the applied sinusoidal voltage waveform, an adjustable power supply that adjusts the amplitude of the square wave output by the power switching circuit, and an amplitude detector that controls the output level of the adjustable power supply. The power switching circuit output, when converted to a sinusoid, provides the effect of an adjustable reactance.

Claims

1. An adjustable reactance generator for a resonant inductive power transfer system, comprising:

a comparator receiving an input sinusoidal waveform and outputting a square wave that retains the frequency and phase of the input sinusoidal waveform;

a power switching circuit that receives said square wave as a control signal, said power switching circuit outputting a square wave that retains the frequency and phase of the input sinusoidal waveform;

an adjustable power supply that adjusts the amplitude of the square wave outputted by said power switching circuit;

an amplitude detector that controls the output level of the adjustable power supply based on an amplitude of the input sinusoidal waveform such that the frequency, phase and amplitude of the input sinusoidal waveform are replicated with the square wave outputted by the power switching circuit; and

means for converting the output of the power switching circuit into a sinusoid having an adjustable reactance and providing said converted output of said power switching circuit to a load of the resonant inductive power transfer system.

2. The adjustable reactance generator of claim 1, wherein the power switching circuit comprises a half-bridge circuit comprising two power switching devices.

3. The adjustable reactance generator of claim 1, wherein the power switching circuit comprises a full-bridge configuration, a flyback configuration, a resonant tank with single ended or push-pull drive configuration, or a single or double ended forward converter configuration.

4. The adjustable reactance generator of claim 1, wherein the adjustable power supply comprises a controlled voltage source or a controlled current source.

5. The adjustable reactance generator of claim 1, wherein the adjustable power supply comprises a switch mode power supply.

6. The adjustable reactance generator of claim 1, wherein the converting means comprises a Thevenin impedance and an LC resonant air core transfer transformer.

7. A method of adjusting the reactance of an adjustable reactance generator of a resonant inductive power transfer system, comprising:

generating from an input sinusoidal waveform a square wave that retains the frequency and phase of the input sinusoidal waveform;

applying said square wave as a control signal to a power switching circuit whereby said power switching circuit outputs a square wave that retains the frequency and phase of the input sinusoidal waveform;

adjusting the amplitude of the square wave outputted by said power switching circuit to a desired level based on an amplitude of the input sinusoidal waveform such that the frequency, phase and amplitude of the input sinusoidal waveform are replicated with the square wave outputted by the power switching circuit;

converting the amplitude adjusted square wave output to a sinusoidal signal having an adjustable reactance; and

providing said converted output to a load of the resonant inductive power transfer system.