A DC power supply may use an input supply surge protection circuit that may be robust against positive and negative power surges. DC power may be provided through a first unidirectional circuit component such as a diode or selectively controlled MOSFET coupled in parallel with a transient voltage suppressor or Zener diode. The first unidirectional circuit component may have a first voltage rating and the transient voltage suppressor or Zener diode may have a second voltage rating lower than the first voltage rating. This may allow current to flow backward over the transient voltage suppressor or Zener diode to protect the first unidirectional circuit component from exposure to voltage beyond the first voltage rating in a power surge.

A protection circuit including an auxiliary winding, a rectifier unit, the filter unit, a voltage divider unit and a controller is provided. The auxiliary winding is configured to induce an AC voltage. The rectifier unit is coupled to the auxiliary winding and configured to rectify the AC voltage into a DC voltage. The filter unit is coupled to the rectifier unit and configured to filter the DC voltage into a DC filter voltage. The voltage divider unit is coupled to the rectifier unit and the filter unit to transmit the DC filter voltage. The controller is coupled to the voltage divider unit and configured to detect a partial voltage of the DC filter voltage and detect whether to activate a protection mechanism according to the partial voltage.

A power supply with lightning protection includes a surge voltage suppression apparatus, an electromagnetic interference control circuit, a surge current bypass apparatus, an active bridge rectifier circuit, a power factor correction circuit, and a DC-to-DC conversion circuit. The surge voltage suppression apparatus is used to increase a tolerance of a surge voltage for the power supply. The electromagnetic interference control circuit is coupled to the surge voltage suppression apparatus. The surge current bypass apparatus is used to increase a tolerance of a surge current for the power supply. The active bridge rectifier circuit is used to rectify an input voltage. The power factor correction circuit is used to adjust the rectified input voltage to provide an adjusted input voltage on a bulk capacitor. The DC-to-DC conversion circuit is used to convert the adjusted input voltage into a DC output voltage.

A device includes a rectifier connected to a receiver coil, a first overvoltage protection apparatus connected between inputs of the rectifier and ground, and a second overvoltage protection apparatus connected between an output of the rectifier and ground, wherein in an overvoltage event, the first overvoltage protection apparatus and the second overvoltage protection apparatus are controlled based upon a comparison between a switching frequency of the device and a predetermine frequency threshold.

In one embodiment, an apparatus includes a surge voltage blocker circuit to couple between a distribution grid network and a grid-side power converter of a power conversion system. The surge voltage blocker circuit may include a plurality of series-coupled AC switch circuits, each including: a bidirectional switch formed of a first power transistor and a second power transistor; and a transient voltage suppression device coupled in parallel with the bidirectional switch.

One general aspect includes methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for fault protection of a bidirectional wireless power transfer system. The method includes the actions of detecting, by control circuitry of a wireless power transfer device, a fault for the bidirectional wireless power transfer system. Identifying an operating personality of the wireless power transfer device and a hardware configuration of the wireless power transfer device. Identifying, in response to detecting the fault and based on the operating personality and the hardware configuration, protection operations for protecting the wireless power transfer device from the fault. Controlling operations of the wireless power transfer device according to the protection operations. Other implementations of this aspect include corresponding systems, circuitry, controllers, apparatus, and computer programs, configured to perform the actions of the methods, encoded on computer storage devices.

An isolated switched-mode power converter converts power from an input source into power for an output load. Power switches within a primary-side power stage control the amount of power input to the power converter and, ultimately, provided to the output load. A digital controller on the secondary side of the power converter generates signals to control the power switches. This controller also senses a rectified voltage on the secondary side of the power converter and uses this sensed voltage to detect fault conditions of the primary side. For example, the sensed rectified voltage is used to detect undervoltage or overvoltage conditions of the input power source of the power converter, or faulty power switches within the primary-side power stage.

The problem to be solved is to provide a system and a method to protect the regulator rectifiers from the reverse voltage condition and the short circuit condition, and the problem is solved in the present invention by a system and a method that use a protection device including a control unit that receives an input from the circuit based on the reverse voltage condition and the short circuit condition, and based on the existence of at least one of the condition or a combination thereof, the control unit switches a switching unit from an ON state to an OFF state, thereby breaking the circuit between the regulator rectifier device and the load section, thus protecting the regulator rectifier device.

Methods, systems, and devices for protecting a wireless power transfer system. One aspect features a sensor network for a wireless power transfer system. The sensor network includes a differential voltage sensing circuit and a current sensing circuit. The differential voltage sensing circuit is arranged within a wireless power transfer system to measure a rate of change of a voltage difference between portions of an impedance matching network and generate a first signal representing the rate of change of the voltage difference. The current sensing circuit is coupled to the differential voltage sensing circuit and configured to calculate, based on the first signal, a current through a resonator coil coupled to the wireless power transfer system.

A power supply includes a power converter, a protection circuit, and a control circuit. The protection circuit includes an input for receiving an input voltage, an output for providing an output voltage to the power converter, a first switching device coupled in a current path between the input and the output, and a second switching device coupled across the first switching device. The control circuit is configured to sense the input voltage and the output voltage, in response to the output voltage exceeding a first defined threshold, turn off the first switching device and turn on the second switching device to supply power to the power converter, and in response to the input voltage exceeding a second defined threshold, turn off the second switching device to disconnect the power source from the power converter. Other example power supplies and protection circuits are also disclosed.