Wireless power transmission/reception apparatus and method

A wireless power transmission/reception apparatus, comprising:

• a wireless power transmission unit configured to:
• receive externally input power,
• generate a wireless power signal to be transmitted in a wireless manner,
• transmit the generated wireless power signal using magnetic resonance,
• receive a reflected wireless power signal,
• determine whether a load device is present, and
• transmit a further wireless power signal when it is determined that the load device is present in such a way that variations in impedance and output power depending on a variation in a distance to the load device are tracked, and the further wireless power signal, which has been matched to an optimal impedance and which has been amplified to a maximum level of output power, is transmitted in a wireless manner to allow power to be supplied to the load device;
• and
• a wireless power reception unit connected to the load device, and configured to receive the wireless power signal from the wireless power transmission unit using magnetic resonance, to provide the wireless power signal to the load device connected to the wireless power reception unit, and to reflect the reflected wireless power signal, which was not consumed, towards the wireless power transmission unit,
• wherein the wireless power transmission unit comprises:
• a frequency oscillator configured to receive the externally input power and generating a wireless power signal desired to be transmitted;
• a power amplifier configured to amplify the wireless power signal generated by the frequency oscillator and output an amplified wireless power signal;
• a first resonant antenna configured to transmit the wireless power signal using magnetic resonance, and receive the reflected wireless power signal that is reflected from the wireless power reception unit using magnetic resonance;
• an impedance matching unit disposed between the power amplifier and the first resonant antenna and configured to vary impedance to an optimal impedance so as to provide impedance matching between the power amplifier and the first resonant antenna;
• a directional power coupler disposed between the power amplifier and the impedance matching unit or between the impedance matching unit and the first resonant antenna, and configured to have directionality such that the wireless power signal, which is inputted from the power amplifier or the impedance matching unit through a first port, is outputted to the first resonant antenna through a second port, and such that the reflected wireless power signal, which is inputted from the first resonant antenna through the second port, is output through a third port;
• an output power detector configured to detect output power from the wireless power signal which is outputted from the second port of the directional power coupler, and output detected output power;
• a reflected power detector configured to detect reflected power from the reflected wireless power signal which is outputted from the third port of the directional power coupler, and output the detected reflected power;
• a variable voltage regulator configured to vary an input voltage and transfer a boosted output voltage to the power amplifier such that a wireless power signal to be amplified by the power amplifier has a maximum level of output power depending on an output power-to-reflected power ratio;
• and
• a transmission controller configured to:
• detect whether the load device is present depending on the output power-to-reflected power ratio calculated using the output power and the reflected power which have been inputted, control the impedance matching unit so that when the load device is present, impedance attributable to the variation in the distance to the load device varies depending on the output power-to-reflected power ratio, thereby realizing matching to an optimal impedance, and
• control the variable voltage regulator so that when the load device is present, the output power attributable to the variation in the distance to the load device varies depending on the output power-to-reflected power ratio, thereby allowing maximum output power to be tracked, and
• perform control such that the wireless power signal which has been matched to the optimal impedance and has been amplified to the maximum output power is transmitted through the first resonant antenna,
• wherein the transmission controller comprises:
• a comparison module configured to compare the output power-to-reflected power ratio, calculated using the output power and the reflected power which have been inputted, with a preset value, thus determining whether a load device is present;
• an impedance tracking module configured to control the impedance matching unit such that when it is determined that the load device is present, impedance attributable to the variation in the distance to the load device varies depending on the output power-to-reflected power ratio, thereby tracking optimal impedance;
• and
• a power tracking module configured to control the variable voltage regulator such that when it is determined that the load device is present, output power attributable to the variation in the distance to the load device varies depending on the output power-to-reflected power ratio, thereby tracking maximum output power,
• wherein the impedance tracking module comprises:
• a first voltage division circuit provided with a plurality of series-connected resistors which have different values and are disposed between a reflected voltage detected from the reflected power and a ground, and configured to divide the reflected voltage into a plurality of reflected voltages using the plurality of resistors;
• a first comparison circuit provided with a plurality of comparators, each individually receiving a corresponding one of the plurality of reflected voltages outputted from the first voltage division circuit and an output voltage detected from the output power, and determining whether the reflected voltage is at level lower than or higher than the output voltage via comparison of voltages, the plurality of reflected voltages being converted into levels by the comparators;
• and
• a first output terminal selection circuit configured to allow any one high-level reflected voltage of the plurality of reflected voltages, converted into the levels by the first comparison circuit, to be outputted through one selected from among the plurality of output terminals,
• wherein the impedance tracking module tracks an optimal impedance in response to a first control signal which includes information about the output terminal selected by the first output terminal selection circuit, thus controlling the impedance matching unit.