Wireless power transmitter

摘要

An example wireless power transmitter is configured for wirelessly transmitting a signal to a power receiving apparatus including a first resonance circuit and a load circuit. The first resonance circuit includes a power receiving coil and a first capacitor. The example wireless power transmitter includes a power supply that has a variable oscillation frequency and generates a signal having the oscillation frequency; a second resonance circuit that transmits the signal to the power receiving apparatus; a measuring unit that measures a signal reflection coefficient, the signal reflection coefficient being determined based on magnitude of the signal and magnitude of a signal reflected on the second resonance circuit to the power supply; and a controller that detects a value of the oscillation frequency making the signal reflection coefficient smaller than or equal to a threshold value, and calculates an electromagnetic coupling coefficient between the power transmission coil and the power receiving coil based on the detected value.

主权项

1. A wireless power transmitter for wirelessly transmitting a signal to a power receiving apparatus having a first resonance circuit and a load circuit, wherein the first resonance circuit includes a power receiving coil and a first capacitor, the wireless power transmitter comprising:
a power supply that has a variable oscillation frequency and generates signals; a second resonance circuit that transmits the signals to the power receiving apparatus; a measuring unit that measures signal reflection coefficients associated with respective ones of the generated signals; and a controller that controls one or both of the oscillation frequency and a parameter of the second resonance circuit based on a calculated electromagnetic coupling coefficient between the power transmission coil and the power receiving coil, the electromagnetic coupling coefficient being calculated, before transmitting signals for powering the load circuit, by at least controlling the power supply to generate signals each having a respective oscillation frequency; controlling the measuring unit to measure signal reflection coefficients, each signal reflection coefficient being determined based on magnitude of one of the signals and magnitude of a corresponding signal reflected on the second resonance circuit to the power supply; detecting a value of the oscillation frequency making the signal reflection coefficient smaller than or equal to a threshold value; and calculating the electromagnetic coupling coefficient based on the detected value.