Abstract: A method for calculating the steady-state fault current of a modular multilevel converter (MMC) comprises calculating the dc-side critical resistance values RA/B, RB/C and RC/D of the MMC based on the bridge arm inductance coefficient k and the ac-side reactance Xac of the MMC; Then, determining the operating modes of the MMC based on RA/B, RB/C and RC/D, and calculating the steady-state dc fault current and the conduction overlap angle respectively under various operating modes without considering the ac-side resistance based on the parameters k, Us, Rdc and the dc-side critical resistance values RA/B, RB/C and RC/D; After that the steady-state AC fault current amplitude and phase angle for each operating mode without considering the AC side resistance are calculated based on the DC current and conduction overlap angle for each operating mode, respectively. Finally, the steady-state AC fault current amplitude and phase angle are calculated for various operating modes considering the AC side resistance.

Abstract: An embedded GPU-based wideband parallel channelized receiving method includes: constructing an OpenCL platform; decimating a wideband signal read in the OpenCL platform at an interval indicated by the number of channels; assigning data in each row to one of multiple work groups for processing; filtering data on each of channels based on a coefficient of a polyphase filter on a branch; multiplying the filtered data by a factor; and performing an FFT on the formed two-dimensional matrix by columns to obtain data outputted from each of the channels.

Abstract: The present invention relates to the field of digital signal processing, and in particular to a Costas sequence time-frequency joint synchronization method based on all-phase spectrum correction. The method improves the defects existing in a discrete frequency spectrum correction algorithm using short-time Fourier transform and sliding correlation. The improvement mainly comprises: the present disclosure provides a solution based on iterative optimization: when an actual frequency offset is an integral multiple of the spectral resolution, a large error can occur, frequency offset correction and time delay correction are carried out on a signal by using an estimated value having a large estimated error, then estimation is carried out again, and the frequency offset of the signal is not a special value by means of an iteration mode.

Abstract: The present invention relates to the field of digital signal processing, and in particular to a Costas sequence time-frequency joint synchronization method based on all-phase spectrum correction. The method improves the defects existing in a discrete frequency spectrum correction algorithm using short-time Fourier transform and sliding correlation. The improvement mainly comprises: the present disclosure provides a solution based on iterative optimization: when an actual frequency offset is an integral multiple of the spectral resolution, a large error can occur, frequency offset correction and time delay correction are carried out on a signal by using an estimated value having a large estimated error, then estimation is carried out again, and the frequency offset of the signal is not a special value by means of an iteration mode.

Abstract: A method for calculating the steady-state fault current of a modular multilevel converter (MMC) comprises calculating the dc-side critical resistance values RA/B, RB/C and RC/D of the MMC based on the bridge arm inductance coefficient k and the ac-side reactance Xac of the MMC; Then, determining the operating modes of the MMC based on RA/B, RB/C and RC/D, and calculating the steady-state dc fault current and the conduction overlap angle respectively under various operating modes without considering the ac-side resistance based on the parameters k, Us, Rdc and the dc-side critical resistance values RA/B, RB/C and RC/D; After that the steady-state AC fault current amplitude and phase angle for each operating mode without considering the AC side resistance are calculated based on the DC current and conduction overlap angle for each operating mode, respectively. Finally, the steady-state AC fault current amplitude and phase angle are calculated for various operating modes considering the AC side resistance.

Abstract: It discloses a ring-connected bridge-type multi-port hybrid DC circuit breaker. When the number of ports is n, n is an integer greater than or equal to 2, the ring-connected bridge-type multi-port hybrid DC circuit breaker includes: an upper DC bus bar, a lower DC bus bar, n thyristor arms, n diode arms, a main breaker branch, and n bypass branches; each thyristor arm connects in series with a diode arm, forming a series circuit; a bypass branch is connected between every two adjacent series circuits, a port is provided at the connection point of the thyristor arm and the diode arm in each series circuit, and the port is used to connect the protected components or the DC lines.

Abstract: It discloses a ring-connected bridge-type multi-port hybrid DC circuit breaker. When the number of ports is n, n is an integer greater than or equal to 2, the ring-connected bridge-type multi-port hybrid DC circuit breaker includes: an upper DC bus bar, a lower DC bus bar, n thyristor arms, n diode arms, a main breaker branch, and n bypass branches; each thyristor arm connects in series with a diode arm, forming a series circuit; a bypass branch is connected between every two adjacent series circuits, a port is provided at the connection point of the thyristor arm and the diode arm in each series circuit, and the port is used to connect the protected components or the DC lines.

Abstract: The present invention discloses a BiSbTeSe-based thermoelectric material, whose general formula is BimSbnTexSeyMz; wherein, m=0.4-0.6, n=1.4-1.6, x=2.7-2.9, y=0.075-0.3, z=0.02-0.15, M is one or more elements of S, Si, P, Ge, Sn, Ce, Li, I, Br, Al, Cu, Ag, Yb, Tm, La, Gd and Dy. The BiSbTeSe-based thermoelectric material is prepared through powder mixing, alloy smelting and other steps. The BiSbTeSe-based thermoelectric material in the present invention has the advantages of low thermal conductivity and good thermoelectric properties, which expands the application area of thermoelectric material.