A controller including a memory having computer-readable instructions stored therein; and a processor configured to execute the computer-readable instructions to: estimate a synthesized grid voltage vector angle at a terminal of an alternating current (AC) grid based on at least an adjusted angle, to generate Pulse Width Modulation (PWM) signals to control power switches of the AFE inverter based on at least the synthesized grid voltage vector angle, and to control the AFE inverter to exchange power between the AC grid and a load based on the PWM signals.

A controller including a memory having computer-readable instructions stored therein; and a processor configured to execute the computer-readable instructions to: estimate a synthesized grid voltage vector angle at a terminal of an alternating current (AC) grid based on at least an adjusted angle, to generate Pulse Width Modulation (PWM) signals to control power switches of the AFE inverter based on at least the synthesized grid voltage vector angle, and to control the AFE inverter to exchange power between the AC grid and a load based on the PWM signals.

An electronic device and phase detector are provided. The phase detector includes a first input terminal, a second input terminal, a first input buffer, and a second input buffer. The first input buffer is electrically connected to the first input terminal. The second input buffer is electrically connected to the second input terminal.

Embodiments provide a device that includes a first circuit having a first input to receive a first sine wave signal and a second input to receive a second sine wave signal in quadrature with respect to each other and a current mode logic gate having a first input coupled to a first output of the first circuit and a second input coupled to a second output of the first circuit. The first circuit configured to deliver a first square wave signal and a second square wave signal. The current mode logic gate is configured to deliver a third square wave signal at a first level and a fourth square wave signal at a second level when the first and second square wave signals are simultaneously at their first levels and the first square wave signal is ahead of the second square wave signal.

A digital measurement system includes an oscillator, a mixer, and a controller coupled to each other. The oscillator provides a reference signal having a second frequency. The mixer generates a down-converted signal based on the output signal and the reference signal. The controller then determines a characteristic of the output signal (e.g., frequency or phase) based on the down-converted signal. An analog measurement system includes a filter having a center frequency, a rectifier, and a controller. The filter filters the output signal and the rectifier rectifies the filtered signal. The controller samples the rectified signal and determines a characteristic of the output signal based on the level of the rectified signal. The reference signal controller may adjust a characteristic of the output signal based on the determined frequency and/or phase of the output signal.

A digital measurement system includes an oscillator, a mixer, and a controller coupled to each other. The oscillator provides a reference signal having a second frequency. The mixer generates a down-converted signal based on the output signal and the reference signal. The controller then determines a characteristic of the output signal (e.g., frequency or phase) based on the down-converted signal. An analog measurement system includes a filter having a center frequency, a rectifier, and a controller. The filter filters the output signal and the rectifier rectifies the filtered signal. The controller samples the rectified signal and determines a characteristic of the output signal based on the level of the rectified signal. The reference signal controller may adjust a characteristic of the output signal based on the determined frequency and/or phase of the output signal.

The method determines an input phase differential () between two input signals. A phase detector is provided that has pairs of transistors and a first impedance (R1) connected to a first branch carrying a first signal (Iout_left) and a second impedance (R2) connected to a second branch carrying a second signal (Iout_right). The first signal (Iout_left) in the first branch is set as a first sum of a common mode output signal (Icm) and a differential mode output signal (Idm). The second signal (Iout_right) in the second branch is set as a second sum of the common mode output signal (Icm) minus the differential mode output signal (Idm). A relationship between the first impedance (R1) and the second impedance (R2) is adjusted until a differential mode output voltage (Vdm) of the phase detector is zero. The input phase differential () is determined when the differential mode output voltage (Vdm) is zero.

The method determines an input phase differential () between two input signals. A phase detector is provided that has pairs of transistors and a first impedance (R1) connected to a first branch carrying a first signal (Iout_left) and a second impedance (R2) connected to a second branch carrying a second signal (Iout_right). The first signal (Iout_left) in the first branch is set as a first sum of a common mode output signal (Icm) and a differential mode output signal (Idm). The second signal (Iout_right) in the second branch is set as a second sum of the common mode output signal (Icm) minus the differential mode output signal (Idm). A relationship between the first impedance (R1) and the second impedance (R2) is adjusted until a differential mode output voltage (Vdm) of the phase detector is zero. The input phase differential () is determined when the differential mode output voltage (Vdm) is zero.

This present inversion provides a digital closed-loop fiber optical current sensor. The modulation signal of the optical wave phase modulator of the fiber optical current sensor system is modulation square wave, signal processing system extracts any harmonic wave of the photoelectric converter output modulation square waves, and extracts the measured current information from it. The preamplifier of signal processing system is transimpedance amplifier TIA, the bandwidth is extracted 1/650 instantaneous amplitude square wave directly from the modulation square wave (existing), thus the thermal noise of the preamplifier output and shot noise level is reduced to the existing technology of below 1/650; the current-voltage gain of transimpedance amplifier TIA does not depend on the feedback network resistance, thus it can have high current-voltage conversion gain and use low resistance in the feedback network TIA at the same time. So it can reduce resistance thermal noise to negligible that is accounted for a large proportion of TIA output noise.

A digital measurement system includes an oscillator, a mixer, and a controller coupled to each other. The oscillator provides a reference signal having a second frequency. The mixer generates a down-converted signal based on the output signal and the reference signal. The controller then determines a characteristic of the output signal (e.g., frequency or phase) based on the down-converted signal. An analog measurement system includes a filter having a center frequency, a rectifier, and a controller. The filter filters the output signal and the rectifier rectifies the filtered signal. The controller samples the rectified signal and determines a characteristic of the output signal based on the level of the rectified signal. The reference signal controller may adjust a characteristic of the output signal based on the determined frequency and/or phase of the output signal.