Over voltage protection for a wireless power transfer system
A wireless power transfer system is disclosed. The wireless power transfer system includes a first converting unit configured to convert a first DC voltage of an input power to an AC voltage. Further, the wireless power transfer system includes a contactless power transfer unit configured to transmit the input power having the AC voltage. Also, the wireless power transfer system includes a second converting unit configured to convert the AC voltage to a second DC voltage and transmit the input power having the second DC voltage to an electric load. Additionally, the wireless power transfer system includes a switching unit configured to decouple the electric load from the contactless power transfer unit if the second DC voltage across the electric load is greater than a first threshold value.
1 . An apparatus for receiving wireless power, comprising:
a secondary coil configured to wirelessly receive a wireless power from a primary coil of a contactless power transfer unit;
a converting unit configured to convert the wireless power from an AC voltage to an output power having an output DC voltage and provide the output power to an electric load;
at least one switch configured to decouple the electric load to protect one or more components of the apparatus from over voltage damage; and
a controller electrically coupled to the at least one switch, the controller configured to:
generate a control signal when the output DC voltage exceeds a first threshold value greater than a maximum voltage regulation value;
cause the at least one switch to decouple the electric load using a switching signal that is based, at least in part, on the control signal, and
communicate, to the contactless power transfer unit, the control signal as an indication of a decoupling of the electric load.
2 . The apparatus of claim 1 , wherein the control signal includes an indication to cause the contactless power transfer unit to deactivate power transmission.
3 . The apparatus of claim 1 , wherein the at least one switch short-circuits the secondary coil when the at least one switch is activated.
4 . The apparatus of claim 1 , wherein the maximum voltage regulation value is in a first range of 300V to 400V and the first threshold value is in a second range of 400V to 500V.
5 . The apparatus of claim 1 , further comprising:
a transceiver configured to communicate with a corresponding transceiver of the contactless power transfer unit, wherein the controller communicates the control signal via the transceiver.
6 . The apparatus of claim 5 , wherein the transceiver is further configured to receive a reset signal from the corresponding transceiver of the contactless power transfer unit, and wherein the reset signal causes the controller to control the at least on switch to enable supply of the output power via the converting unit to the electric load in response to processing the reset signal.
7 . The apparatus of claim 1 , wherein the controller is further configured to regulate the output DC voltage when the output DC voltage is above a voltage reference value and below the maximum voltage regulation value.
8 . The apparatus of claim 1 , further comprising:
a switching unit including the at least one switch;
wherein the controller is configured to:
control the switching unit to regulate the output DC voltage across the electric load when the output DC voltage is below the maximum voltage regulation value.
9 . The apparatus of claim 8 , wherein the controller is configured to determine a duty cycle to control a switch of the switching unit using a look-up table that indicates the duty cycle corresponding to different output DC voltages.
10 . A method performed by an apparatus of a wireless power transfer system, the method comprising:
receiving, via a secondary coil, wireless power from a primary coil of a contactless power transfer unit;
converting, by a converting unit, the wireless power from an AC voltage to an output power having an output DC voltage;
providing the output power to an electric load;
generating, by a controller, a control signal when the output DC voltage is at least a first threshold value greater than a maximum voltage regulation value;
causing, by the controller, a least one switch to decouple the electric load to protect one or more components of the apparatus from over voltage damage using a switching signal that is based, at least in part, on the control signal; and
communicating, to the contactless power transfer unit, the control signal as an indication of a decoupling of the electric load.
11 . The method of claim 10 , wherein the control signal includes an indication cause the contactless power transfer unit to deactivate power transmission.
12 . The method of claim 10 , wherein the communicating includes communicating the control signal via a first transceiver to a second transceiver of the contactless power transfer unit.
13 . The method of claim 12 , further comprising:
receiving, by the first transceiver, a reset signal from the second transceiver of the contactless power transfer unit, the reset signal for resetting the at least one switch; and
enabling supply of the output power via the converting unit to the electric load based on the reset signal.
14 . The method of claim 10 , further comprising regulating, by the controller, the output DC voltage when the output DC voltage is above a voltage reference value and below the maximum voltage regulation value.
15 . The method of claim 14 , wherein the regulating the output DC voltage comprises:
determining a duty cycle to control the least one switch; and
controlling the least one switch based, at least in part, on the duty cycle.
16 . The method of claim 15 , wherein the determining the duty cycle includes referring to a look-up table that indicates the duty cycle corresponding to different output DC voltages.
17 . The method of claim 12 , further comprising:
communicating a voltage signal to the contactless power transfer unit, the voltage signal representative of the output DC voltage across the electric load, wherein the voltage signal is communicated to cause the contactless power transfer unit to adjust a switching frequency of a transmitter-side converting unit of the contactless power transfer unit based on the voltage signal.
18 . The apparatus of claim 1 , wherein the controller is further configured to:
communicate a voltage signal to the contactless power transfer unit, the voltage signal representative of the output DC voltage across the electric load, wherein the voltage signal is communicated to cause the contactless power transfer unit to adjust a switching frequency of a transmitter-side converting unit of the contactless power transfer unit based on the voltage signal.