# US 11,444,495 B2 · Precision power level control for extended range wireless power transfer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,444,495 B2 - Document ID: US11444495B2 - Status: Granted - Kind: B2 - Application number: 16/863,698 - Filed: 2020-04-30 - Published: 2021-11-04 - Granted: 2022-09-13 - Earliest claimed: 2020-04-30 - Assignees: NuCurrent, Inc. - Applicants: NuCurrent, Inc. - Inventors: Jason Green; Andrew Kovacs; Mark Melone; Md Nazmul Alam - Web page: https://patentgrep.com/patent/US11444495B2 ## CPC - H02J 50/80: involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices - H01F 27/24: Magnetic cores - H01F 27/36: Electric or magnetic shields or screens (movable for varying inductance H01F21/10) - H01F 38/14: Inductive couplings - H02J 50/12: of the resonant type - H02J 50/70: involving the reduction of electric, magnetic or electromagnetic leakage fields - H02J 50/60: responsive to the presence of foreign objects, e.g. detection of living beings - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES ## Abstract A power transmitter for wireless power transfer includes a control and communications unit configured to provide power control signals to a power supply external to the power transmitter for controlling a power level of a power signal configured for transmission to a power receiver, the power supply configured to configure a direct current (DC) power based on the power control signals. The power transmitter further includes an inverter circuit configured to receive the DC power from the power supply external to the power transmitter and convert the input power to a power signal. The power transmitter further includes a coil formed of wound Litz wire and including at least one layer, the coil defining, at least, a top face and shielding 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. ## Claims ### Claim 1 A power transmitter for wireless power transfer at an operating frequency selected from a range of about 87 kilohertz (kHz) to about 205 kHz, the power transmitter comprising: a control and communications unit configured to: provide power control signals to a power supply external to the power transmitter, for controlling a power level of an alternating current (AC) power signal configured for transmission to a power receiver, the AC power signal having an initial root mean square voltage, the power supply configured to configure a direct current (DC) power based on the power control signals and including 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, and provide the voltage regulation instructions to the voltage regulator to control the DC voltage of the DC power, wherein the voltage regulation instructions include voltage step up instructions or voltage step down instructions for the voltage regulator, the voltage step up instructions and voltage step down instructions having a step level, the step level being a change in voltage at which the voltage regulator is configured to step up or step down the DC voltage of the DC power for the purposes of configuring the initial root mean square voltage of the AC power signal, and generate a pulse width modulation signal for configuring an AC frequency for the AC power signal, at the operating frequency, the pulse width modulation signal modified by a duty cycle alteration, the duty cycle alteration configured to decrease the initial root mean square voltage of the AC power signal to a shifted root mean square voltage, the shifted root mean square voltage being less than the initial root mean square voltage; an inverter circuit configured to receive DC power from the power supply external to the power transmitter and convert the DC power to the AC power signal based on the pulse width modulation signal; and a coil configured to transmit the AC power signal to the power receiver, the coil formed of wound Litz wire and including at least one layer. ### Claim 2 (depends on 1) The power transmitter of claim 1, wherein the control and communications unit is further configured to receive power request signals from the power receiver, and determine the power control signals based on the power request signals. ### Claim 3 (depends on 1) The power transmitter of claim 1, wherein the power supply is configured to: configure an input DC power to generate the DC power supplied based on the power control signals, and provide the DC power to the inverter circuit. ### Claim 4 (depends on 1) The power transmitter of claim 1, wherein the step level is in a range of about 10 millivolts (mV) to about 500 mV. ### Claim 5 (depends on 1) The power transmitter of claim 1, wherein the step level is about 200 mV. ### Claim 6 (depends on 1) The power transmitter of claim 1, wherein the duty cycle alteration is further configured to alter an amount of power transmitted to the power receiver over a period of time. ### Claim 7 A power transmitter for wireless power transfer at an operating frequency selected from a range of about 87 kilohertz (kHz) to about 205 kHz, the power transmitter comprising: a control and communications unit configured to: provide power control signals to a power supply external to the power transmitter for controlling a power level of an alternating current (AC) power signal configured for transmission to a power receiver, the AC power signal having an initial root mean square voltage, the power supply configured to configure a direct current (DC) power based on the power control signals and including a voltage regulator and a power supply controller configured to receive the power control signals, and generate voltage regulation instructions for altering a DC voltage of the DC power, based on the power control signals, and provide the voltage regulation instructions to the voltage regulator to control the DC voltage of the DC power, wherein the voltage regulation instructions include voltage step up instructions or voltage step down instructions for the voltage regulator, the voltage step up instructions and voltage step down instructions having a step level, the step level being a change in voltage at which the voltage regulator is configured to step up or step down the DC voltage of the DC power for the purposes of configuring the initial root mean square voltage of the AC power signal, and generate a pulse width modulation signal for configuring an AC frequency for the AC power signal, at the operating frequency, the pulse width modulation signal modified by a duty cycle alteration, the duty cycle alteration configured to decrease the initial root mean square voltage of the AC power signal to a shifted root mean square voltage, the shifted root mean square voltage being less than the initial root mean square voltage; an inverter circuit configured to receive DC power from the power supply external to the power transmitter and convert the DC power to the AC power signal based on the pulse width modulation signal; a coil configured to transmit the AC power signal to the power receiver, the coil formed of wound Litz wire and including at least one layer, the coil defining, at least, a top face; and a shielding 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. ### Claim 8 (depends on 7) The power transmitter of claim 7, wherein the shielding is an E-Core type shielding and the cavity is configured in an E-shape configuration. ### Claim 9 (depends on 7) The power transmitter of claim 7, wherein a shielding outer edge of the shielding extends about 4.5 millimeters (mm) to about 6.5 mm outward from a coil outer edge of the coil. ### Claim 10 (depends on 7) The power transmitter of claim 7, wherein the coil has an outer diameter length in a range of about 40 mm to about 50 mm. ### Claim 11 (depends on 7) The power transmitter of claim 7, wherein the coil has an inner diameter length in a range of about 15 mm to about 25 mm. ### Claim 12 (depends on 7) The power transmitter of claim 7, wherein the at least one layer comprises a first layer and a second layer. ### Claim 13 (depends on 12) The power transmitter of claim 12, wherein the first layer includes a first number of turns in a range of about 4 turns to about 5 turns, and wherein the second layer includes a second number of turns in a range of about 4 turns to about 5 turns. ### Claim 14 A system for wireless power transfer at an operating frequency selected from a range of about 87 kilohertz (kHz) to about 205 kHz, the system comprising: a power supply that is external to a power transmitter; and the power transmitter including: a control and communications unit configured to: provide power control signals for controlling a power level of an alternating current (AC) power signal configured for transmission to a power receiver, the AC power signal having an initial root mean square voltage, and generate a pulse width modulation signal for configuring an AC frequency for the AC power signal, at the operating frequency, the pulse width modulation signal modified by a duty cycle alteration, the duty cycle alteration configured to decrease the initial root mean square voltage of the AC power signal to a shifted root mean square voltage, the shifted root mean square voltage being less than the initial root mean square voltage, an inverter circuit configured to receive a direct current (DC) power from the power supply external to the power transmitter and convert the DC power to the AC power signal based on the pulse width modulation signal, a coil configured to transmit the AC power signal to the power receiver, the coil formed of wound Litz wire and including at least one layer, the coil defining, at least, a top face, and a shielding 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, and wherein the power supply external to the power transmitter is configured to configure the DC power based on the power control signals, the power supply including: a voltage regulator, 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, the voltage regulation instructions including voltage step up instructions or voltage step down instructions for the voltage regulator, the voltage step up instructions and voltage step down instructions having a step level, the step level being a change in voltage at which the voltage regulator is configured to step up or step down a DC voltage of the DC power, and provide the voltage regulation instructions to the voltage regulator to control a DC voltage of the DC power. ### Claim 15 (depends on 14) The system of claim 14, wherein the step level is in a range of about 10 millivolts (mV) to about 500 mV. ### Claim 16 (depends on 14) The system of claim 14, wherein the step level is about 200 mV.