Active rectification in wireless power systems
AssigneeWiTricity Corporation
InventorsMilisav Danilovic, Conor Rochford
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Abstract
Disclosed herein are methods and systems for controlling an active rectifier of a wireless power receiver. The exemplary methods can include determining a reference value of a current into the rectifier, the reference value being based on a load requirement; determining a required value change in a present input current into the rectifier based on the reference value; transmitting, to a wireless power transmitter, a signal representative of the required value change in the present input current; determining a new value of the present input current after transmitting the signal; and, when the new value is within a predetermined range of the required value change, driving at least one transistor in the rectifier with a PWM signal based on the new value.
Claims26
A method for controlling an active rectifier of a wireless power receiver that comprises a first transistor, a second transistor, a first snubber capacitor coupled in parallel to the first transistor, and a second snubber capacitor coupled in parallel to the second transistor, the method comprising:
- determining a reference value of a current into the rectifier, the reference value being based on a load requirement;
- determining a required value change in a present input current into the rectifier based on the reference value;
- transmitting, to a wireless power transmitter, a signal representative of the required value change in the present input current;
- determining a new value of the present input current after transmitting the signal;
- and
- when the new value is within a predetermined range of the required value change:
- detecting phase information associated with the new value of the present input current, wherein detecting the phase information associated with the new value comprises:
- detecting zero crossing information associated with the new value of the present input current;
- and
- providing the zero crossing information to a phase-locked loop module, the module comprising a XOR logic gate or a charge pump;
- generating a PWM signal based on the detected phase information;
- and
- driving at least one of the first transistor or second transistor with the generated PWM signal, wherein the method further comprises:
- setting a ramp signal associated with the second transistor to zero;
- after detecting a first zero crossing information, discharging the first snubber capacitor thereby reducing an input voltage of the active rectifier to zero and turning on a body diode of the first transistor;
- turning off the second transistor, thereby charging the second snubber capacitor to a load voltage of the wireless power receiver;
- turning on the first transistor;
- setting a ramp signal associated with the first transistor to zero;
- after detecting a second zero crossing information, discharging the second snubber capacitor thereby reducing the input voltage of the active rectifier to zero and turning on a body diode of the second transistor;
- turning off the first transistor, thereby charging the first snubber capacitor to the load voltage;
- and
- turning on the second transistor.
A controller for controlling an active rectifier of a wireless power receiver that comprises a first transistor, a second transistor, a first snubber capacitor coupled in parallel to the first transistor, and a second snubber capacitor coupled in parallel to the second transistor, wherein the controller is coupled to the rectifier and is configured to perform the steps comprising:
- determining a reference value of a current into the rectifier, the reference value being based on a load requirement;
- determining a required value change in a present input current into the rectifier based on the reference value;
- transmitting, to a wireless power transmitter, a signal representative of the required value change in the present input current;
- determining a new value of the present input current after transmitting the signal;
- and
- when the new value is within a predetermined range of the required value change:
- detecting phase information associated with the new value of the present input current, wherein detecting the phase information associated with the new value comprises:
- detecting zero crossing information associated with the new value of the present input current;
- and
- providing the zero crossing information to a phase-locked loop module, the module comprising (i) a XOR logic gate or (ii) a charge pump;
- generating a PWM signal based on the detected phase information;
- and
- driving at least one of the first and second transistors with the generated PWM signal, wherein the method further comprises:
- setting a ramp signal associated with the second transistor to zero;
- after detecting a first zero crossing information, discharging the first snubber capacitor thereby reducing an input voltage of the active rectifier to zero and turning on a body diode of the first transistor;
- turning off the second transistor, thereby charging the second snubber capacitor to a load voltage of the wireless power receiver;
- turning on the first transistor;
- setting a ramp signal associated with the first transistor to zero;
- after detecting a second zero crossing information, discharging the second snubber capacitor thereby reducing the input voltage of the active rectifier to zero and turning on a body diode of the second transistor;
- turning off the first transistor, thereby charging the first snubber capacitor to the load voltage;
- and
- turning on the second transistor.
Dependencies are inferred from the claim text.