Operating frequency based power level altering in extended range wireless power transmitters

A base station for wireless power transfer at an operating frequency selected from an operating frequency range of about 87 kilohertz (kHz) to about 205 kHz, the base station comprising:

• a control and communications unit configured to provide power control signals and control a power level of a power signal for transmission to a power receiver, wherein the control and communications unit includes a pulse width modulation (PWM) signal generator for determining and selecting the operating frequency from the operating frequency range;
• a power supply external to a power transmitter, wherein the power supply is operable to configure a DC power based on the power control signals, wherein the power supply comprises:
• a voltage regulator, and
• a power supply controller configured to:
• receive the power control signals,
• generate voltage regulation instructions for altering a DC voltage of the DC power based on the power control signals, wherein the voltage regulation instructions comprises one or more instructions to select a base DC voltage for assignment as the DC voltage of the DC power, and wherein the DC power has a base DC voltage for the DC voltage that is selected from one or more preset DC power voltage levels comprising a first base voltage level that is electrically associated with a first base power level and a second base voltage level that is electrically associated with a second base power level, and
• provide the voltage regulation instructions to the voltage regulator to control the DC voltage of the DC power;
• an inverter circuit configured to receive the DC power from the power supply external to the power transmitter and convert the DC power to a power signal;
• a coil structure configured to transmit the power signal to the power receiver, the coil structure comprising at least one layer of wound Litz wire, wherein the coil structure has at least a top face;
• and
• a shielding structure comprising a ferrite core and defining a cavity, the cavity configured such that the ferrite core substantially surrounds all but the top face of the coil structure,
• wherein a frequency shift is determined such that an alternating current (AC) output power level for the power signal is greater than the first base power level and less than the second base power level.

A system for wireless power transfer at an operating frequency selected from an operating frequency range, the operating frequency range being about 87 kilohertz (kHz) to about 205 kHz, the system comprising:

• a power transmitter including
• a control and communications unit configured to provide power control signals to control a power level of a power signal for transmission to a power receiver, wherein the control and communications unit includes a pulse width modulation (PWM) signal generator for determining and selecting the operating frequency from the operating frequency range,
• an inverter circuit configured to receive a direct current (DC) power and convert the DC power to a power signal,
• a coil structure configured to transmit the power signal to the power receiver, the coil structure comprising at least one layer of wound Litz wire, wherein the coil structure has at least a top face, and
• a shielding structure comprising a ferrite core and defining a cavity, the cavity configured such that the ferrite core substantially surrounds all but the top face of the coil structure;
• and
• a power supply that is external to the power transmitter and operable to configure the DC power based on the power control signals, wherein the power supply comprises:
• a voltage regulator to configure the DC power to have a base DC voltage for the DC voltage, and
• a power supply controller configured to:
• receive the power control signals,
• generate voltage regulation instructions for altering the DC power based on the power control signals, wherein the voltage regulation instructions comprises one or more instructions to select the base DC voltage for assignment as the DC voltage of the DC power, wherein the base DC voltage is selected from one or more preset DC power voltage levels comprising a first base voltage level that is electrically associated with a first base power level and a second base voltage level that is electrically associated with a second base power level, and
• provide the voltage regulation instructions to the voltage regulator to configure the DC voltage of the DC power, and
• wherein a frequency shift is determined such that an alternating current (AC) output power level for the power signal is greater than the first base power level and less than the second base power level.