A surge suppression circuit (100) and a microwave oven. The surge suppression circuit (100) comprises: a rectifying part (10), a filtering part (20) and a protecting element (30). The rectifying part (10) comprises a rectifying input side and a rectifying output side, the rectifying input side being connected to a voltage input end. The filtering part (20) is connected to the rectifying output side. The protecting element (30) is provided on the rectifying output side and is connected to the filtering part (20), the protecting element (30) is used for suppressing the overvoltage of the rectifying output side in a surge process, thereby improving the reliability of the rectifying part (10) and the whole microwave oven circuit.

An overvoltage recovery circuit (ORC), a controller for an HVAC system and an HVAC system are disclosed herein. In one embodiment, the ORC includes: (1) a first supply voltage terminal connected to a first voltage supply, (2) a second supply voltage terminal connected to a second voltage supply, (3) interruption circuitry including a switch and a trip terminal connected to the second supply voltage terminal and (4) detection circuitry connected to the first supply voltage terminal and the switch of the interruption circuitry, the detection circuitry configured to operate the switch in response to an overvoltage condition at the first supply voltage terminal.

The invention relates to an electric circuit arrangement for the input protection circuit of a switching power supply, having a surge protection circuit, which is contacted with a supply voltage on an input side and to which a current-compensated choke is connected as a suppression component, said current-compensated choke being connected to a rectifier circuit comprising an energy storage means on an output side.

Via modifications to the circuit technology, such as using two varistors as surge protections, and by using suitable switching elements, such as silicon diodes as rectifier elements and ceramic capacitors as an energy storage means, the input protection circuit is designed such that the requirements, which an expanded input voltage range demands of a surge circuit, are fulfilled.

Furthermore, the invention relates to a switching power supply having an electric circuit arrangement according to the invention for the input protection circuit.

An overvoltage protection circuit is provided which is connected between a rectifier circuit and a load including an input capacitor element connected to both ends of the load. The overvoltage protection circuit includes a semiconductor switch connected between the rectifier circuit and the load, and a control circuit controls the semiconductor switch. When the rectified voltage exceeds a predetermined value, the control circuit turns off the semiconductor switch, and detects a voltage potential difference between both ends of the semiconductor switch, and then, for an interval when the voltage potential difference is zero or a predetermined minute value, the control circuit generates a control voltage for turning on the semiconductor switch, and outputs the control voltage to a control terminal of the semiconductor switch. The overvoltage protection circuit includes a current change circuit that gradually changes a current flowing through the semiconductor switch.

An overvoltage recovery circuit (ORC), a controller for an HVAC system and an HVAC system are disclosed herein. In one embodiment, the ORC includes: (1) a first supply voltage terminal connected to a first voltage supply, (2) a second supply voltage terminal connected to a second voltage supply, (3) interruption circuitry including a switch and a trip terminal connected to the second supply voltage terminal and (4) detection circuitry connected to the first supply voltage terminal and the switch of the interruption circuitry, the detection circuitry configured to operate the switch in response to an overvoltage condition at the first supply voltage terminal.

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.

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.

An overvoltage protection circuit is for a power supply including a power converter, the overvoltage protection circuit having a comparator. The overvoltage protection circuit uses the comparator for comparing the power supply voltage with the reference voltage, and for producing a power supply shutdown signal on the shutdown output terminal when the power supply voltage exceeds the maximal power supply voltage, and for latching said power supply shutdown signal on the shutdown output terminal even if the power supply voltage subsequently drops to a level below the maximal power supply voltage. The overvoltage protection circuit has a reset circuit coupled to the first input of the comparator. The reset circuit is configured for pulling the signal level on the first input below said reference value such that the power supply shutdown signal is reset when a reset signal is given to the reset circuit.

An example method may include generating an alternating current (AC) output at a power source within a borehole in a subterranean formation. An electrical component may receive a direct current (DC) output from a converter circuit coupled to the power source and the electrical component. One or more measurements corresponding to the power source, the converter circuit, the electrical component, or a protection circuit coupled to the converter circuit may be received. Blocking devices within the protection circuit may be selectively caused to block current flow in the converter circuit based, at least in part, on the one or more received measurements.

When switching operations of converter cells are stopped due to temporary voltage reduction in an AC system, a voltage determination unit performs determination regarding a voltage of each DC capacitor after a predetermined period has passed, and a charge control unit transmits a charging gate signal, via a gate control unit, to select a converter cell at a voltage level at which a self-feeding circuit of the converter cell is operable. Thus, a DC capacitor of a converter cell whose voltage is lower than the voltage level at which a self-feeding circuit is operable is charged, thereby enabling switching operations of all the converter cells.