A circuit assembly for monitoring a sinusoidal alternating voltage signal having a comparing element receiving at an input the signal with period T and generating a first output signal at an output based upon the signal exceeding a threshold; a zero crossing detector receives at its input the signal and generates a output signal at its output; a timing element connected to zero crossing detector generates a clock signal dependent on the second output signal; and a flip-flop. The comparing element output is connected to a state-controlled input of the flip-flop and the timing element output is connected to an edge-controlled input of the flip-flop. The flip-flop generates a state signal at its output. The timing element specifies a state change of the clock signal at an instant that differs from the instant at T/4 after a zero crossing of the signal.

A circuit assembly for monitoring a sinusoidal alternating voltage signal having a comparing element receiving at an input the signal with period T and generating a first output signal at an output based upon the signal exceeding a threshold; a zero crossing detector receives at its input the signal and generates a output signal at its output; a timing element connected to zero crossing detector generates a clock signal dependent on the second output signal; and a flip-flop. The comparing element output is connected to a state-controlled input of the flip-flop and the timing element output is connected to an edge-controlled input of the flip-flop. The flip-flop generates a state signal at its output. The timing element specifies a state change of the clock signal at an instant that differs from the instant at T/4 after a zero crossing of the signal.

The present disclosure pertains to systems and methods for measuring electrical parameters in an electric power system. In one embodiment, a system may include a line-mounted wireless current sensor comprising a current monitoring subsystem to generate a current measurement of an alternating current flow through an electrical conductor. The line-mounted wireless current sensor may harvest power from the electrical conductor. A processing subsystem may generate a message comprising the current measurement, and the message may be transmitted at a synchronization point using a wireless communication subsystem. An intelligent electronic device (IED) may receive the message. The IED may further generate a voltage and generate a phasor based on the current measurement and the voltage measurement. A control action subsystem may implement a control action (e.g., selectively connecting or disconnecting a capacitor bank) based on the phasor.

Provided are a failure diagnosis method and apparatus for open circuit failure of a power tube of a three-phase rectifier based on a current signal, relating to a failure diagnosis technique for power electronic equipment and capable of quickly and accurately diagnosing on an open circuit failure of the power tube of the three-phase rectifier without adding a hardware component. The failure diagnosis method only requires a sampled current existing in the control system of the rectifier and some intermediate computing signals and is therefore simple and requires little computing resource. A distorted current after the open circuit failure occurs in the power tube of the rectifier and a positive/negative half cycle where the current is present when the failure occurs serve as diagnostic variables. By analyzing the sampled current, a quick diagnosis on the power tube having the open circuit failure is provided. Thus, the invention is highly applicable.

Provided are a failure diagnosis method and apparatus for open circuit failure of a power tube of a three-phase rectifier based on a current signal, relating to a failure diagnosis technique for power electronic equipment and capable of quickly and accurately diagnosing on an open circuit failure of the power tube of the three-phase rectifier without adding a hardware component. The failure diagnosis method only requires a sampled current existing in the control system of the rectifier and some intermediate computing signals and is therefore simple and requires little computing resource. A distorted current after the open circuit failure occurs in the power tube of the rectifier and a positive/negative half cycle where the current is present when the failure occurs serve as diagnostic variables. By analyzing the sampled current, a quick diagnosis on the power tube having the open circuit failure is provided. Thus, the invention is highly applicable.

A power converter can include a magnetic energy storage element, a main switch, a synchronous rectifier switch, and an energy recovery circuit. The energy recovery circuit can include a resonant circuit and an auxiliary switch configured to operate in conjunction with the main and synchronous rectifier switches to store energy in the resonant circuit and deliver energy therefrom to reduce switching losses associated with the main and synchronous rectifier switches. The converter can be a buck, boost, buck-boost, or other converter type. The auxiliary switch may be operated according to a two-pulse control mode or using a conventional buck converter controller with additional delay elements. The resonant circuit inductance may be a discrete inductor or a parasitic inductance, such as a PCB trace, which may be designed to provide a desired inductance value selected to efficiently provide sufficient energy to achieve reduced switching losses of the main and auxiliary switches.

A power converter can include a magnetic energy storage element, a main switch, a synchronous rectifier switch, and an energy recovery circuit. The energy recovery circuit can include a resonant circuit and an auxiliary switch configured to operate in conjunction with the main and synchronous rectifier switches to store energy in the resonant circuit and deliver energy therefrom to reduce switching losses associated with the main and synchronous rectifier switches. The converter can be a buck, boost, buck-boost, or other converter type. The auxiliary switch may be operated according to a two-pulse control mode or using a conventional buck converter controller with additional delay elements. The resonant circuit inductance may be a discrete inductor or a parasitic inductance, such as a PCB trace, which may be designed to provide a desired inductance value selected to efficiently provide sufficient energy to achieve reduced switching losses of the main and auxiliary switches.

This application relates to methods and apparatus for powering microcontrollers (104), in particular for powering microcontrollers of a personal care product, such as a shaver product (107). The microcontroller is arranged such that a first output port (206-1) of a plurality of output ports of the microcontroller receives, in use, an AC waveform. Each output port has an associated high-side switch (207) electrically connected between the output port and a high-side DC voltage rail and an associated low-side switch (208) electrically connected between the output port and a low-side DC voltage rail. A processing module (202) of the microcontroller is configured to monitor a phase of the AC waveform and to control switching of the associated high-side and low-side switches of the first output port based on the phase of the AC waveform so as to provide a rectified voltage between the high-side DC voltage rail and the low-side voltage rail for powering the processing module. The processing module (202) also controls switching of the associated switches of at least a further output port to output a control signal for controlling at least one aspect of operation of a host device. The processing module is further configured to maintain the associated high-side switch of the first output port in a turned-off state when a monitored voltage of the AC waveform at the first output port is between zero and a monitored voltage at the high-side DC voltage rail, and to maintain the associated high-side switch of the first output port in a turned-on state when the monitored voltage of the AC waveform at the first output port is greater than the monitored voltage at the high-side DC voltage rail.

This application relates to methods and apparatus for powering microcontrollers (104), in particular for powering microcontrollers of a personal care product, such as a shaver product (107). The microcontroller is arranged such that a first output port (206-1) of a plurality of output ports of the microcontroller receives, in use, an AC waveform. Each output port has an associated high-side switch (207) electrically connected between the output port and a high-side DC voltage rail and an associated low-side switch (208) electrically connected between the output port and a low-side DC voltage rail. A processing module (202) of the microcontroller is configured to monitor a phase of the AC waveform and to control switching of the associated high-side and low-side switches of the first output port based on the phase of the AC waveform so as to provide a rectified voltage between the high-side DC voltage rail and the low-side voltage rail for powering the processing module. The processing module (202) also controls switching of the associated switches of at least a further output port to output a control signal for controlling at least one aspect of operation of a host device. The processing module is further configured to maintain the associated high-side switch of the first output port in a turned-off state when a monitored voltage of the AC waveform at the first output port is between zero and a monitored voltage at the high-side DC voltage rail, and to maintain the associated high-side switch of the first output port in a turned-on state when the monitored voltage of the AC waveform at the first output port is greater than the monitored voltage at the high-side DC voltage rail.

A PFC circuit uses a single multifunctional node to detect an inductor current when a power switch is turned ON and a zero-current moment when the power switch is turned OFF. The power switch has a drain connected to an inductor, a source connected to a current-sense resistor, and a gate controlled by a PFC controller with the multifunctional node. A signal-integration circuit is electrically coupled between the drain and the source, to provide a multifunctional signal at the multifunctional node. The PFC controller comprises a first comparator and a zero-current detector. The first comparator compares the multifunctional signal with a first reference signal when the PFC controller turns ON the power switch, to provide over-current protection. The zero-current detector decides, in response to the multifunctional signal when the PFC controller turns OFF the power switch, a zero-current moment when an inductor current flowing through the inductor is about zero.