Abstract: A method and a system for determining a direct current (DC) loop impedance are provided. The method includes: establishing an impedance model for a DC loop of a high-voltage direct current (HVDC) system; scanning parameters in the HVDC system based on the impedance model, to obtain a feasible region of each of the parameters; substituting, for each of the parameters, the parameter in the feasible region into a DC loop impedance equation, to obtain an impedance corresponding to the parameter, the DC loop impedance equation being obtained by transforming the impedance model; and comparing, for each of the parameters, the impedance corresponding to the parameter with a target impedance value, and determining the impedance that meets the target impedance value and the parameter corresponding to the impedance as an optimal impedance and an optimal parameter of the DC loop.

Abstract: A high-efficiency solar multi-layer evaporative seawater desalination device includes a transparent housing. In the device, wedge-shaped recesses are formed on an outer wall of the transparent housing; during seawater desalination, seawater is injected into evaporation trays and sunlight is irradiated on the evaporation trays through the transparent housing; the transparent housing is made of a transparent plastic material, such that sunlight can directly enter the transparent housing and increase a temperature therein to speed up the evaporation; the wedge-shaped recesses are on a shady surface; during desalination, seawater in the evaporation trays absorbs heat and evaporates to form water vapor, such that there is a given temperature difference between the water vapor and the outside; and a lower part of the wedge-shaped recess can serve as a condensation surface, the water vapor condenses on the transparent housing or at the wedge-shaped recess.

Abstract: The invention discloses a method for MGP new energy grid-connected control, wherein, the synchronous motor is connected to a synchronous generator; the new energy module drives the synchronous motor to rotate through a frequency converter; the frequency converter controls the power transmission; and the synchronous motor drives the synchronous generator for grid connection. The present invention has the beneficial effects that: the control method and system provided by the invention can improve the stability and reliability of the grid.

Abstract: The invention discloses a power feedback control system and method of MGP system, including detecting the actual active power delivered by the generator to the grid through the measurement and calculation module; making a difference between the measured active power and the given active power; calculating the frequency regulation amount through the PI regulation module according to the difference, and taking it as feedback; calculating the frequency reference value of the converter in the control system; and fine tuning the frequency of the converter through the PI regulation module; regulating the phase difference through frequency modulation; realizing the goal of controlling the power output, so that when predicting the output power of new energy before MGP is connected to the grid based on power feedback control, the output of the control system will not be delayed and the defects that affect the stability and reliability of the control system will not appear, to ensure the successful introduction of new

Abstract: The invention discloses a method for MGP new energy grid-connected control, wherein, the synchronous motor is connected to a synchronous generator; the new energy module drives the synchronous motor to rotate through a frequency converter; the frequency converter controls the power transmission; and the synchronous motor drives the synchronous generator for grid connection. The present invention has the beneficial effects that: the control method and system provided by the invention can improve the stability and reliability of the grid.

Abstract: Non-fault disturbance-based method and system for measuring short-circuit capacity of a power grid on site including: connecting or disconnecting a reactive compensation device to or from a power grid point of common coupling, to generate a disturbance on a power grid; obtaining total active power and total reactive power of a load of the point of common coupling before the disturbance; determining a vector difference between a voltage of the power grid point of common coupling before the disturbance and a voltage of the power grid point of common coupling after the disturbance; obtaining a voltage effective value of the power grid point of common coupling before the disturbance; obtaining a capacity of the reactive compensation device; and determining a short-circuit capacity of the point of common coupling according to total active power, total reactive power, vector difference between voltages, voltage effective value, and capacity of the reactive compensation device.

Abstract: Non-fault disturbance-based method and system for measuring short-circuit capacity of a power grid on site including: connecting or disconnecting a reactive compensation device to or from a power grid point of common coupling, to generate a disturbance on a power grid; obtaining total active power and total reactive power of a load of the point of common coupling before the disturbance; determining a vector difference between a voltage of the power grid point of common coupling before the disturbance and a voltage of the power grid point of common coupling after the disturbance; obtaining a voltage effective value of the power grid point of common coupling before the disturbance; obtaining a capacity of the reactive compensation device; and determining a short-circuit capacity of the point of common coupling according to total active power, total reactive power, vector difference between voltages, voltage effective value, and capacity of the reactive compensation device.

Abstract: An audio receiver's output clock is synchronized based on a number of input and output audio samples measured over a predetermined sample period. In one embodiment, a sample difference may be determined by subtracting the measured number of input audio samples from the measured number of output audio samples. This sample difference may then be compared to a predetermined threshold. In one embodiment, if the absolute value of the sample difference is less than the predetermined threshold, no adjustment to the output clock may be needed. When the absolute value of the sample difference is greater than the predetermined threshold, the output clock rate may be adjusted either upwards or downwards.

Abstract: An audio receiver's output clock is synchronized based on a number of input and output audio samples measured over a predetermined sample period. In one embodiment, a sample difference may be determined by subtracting the measured number of input audio samples from the measured number of output audio samples. This sample difference may then be compared to a predetermined threshold. In one embodiment, if the absolute value of the sample difference is less than the predetermined threshold, no adjustment to the output clock may be needed. When the absolute value of the sample difference is greater than the predetermined threshold, the output clock rate may be adjusted either upwards or downwards.