38results about How to "There is no detection blind zone" patented technology

The invention discloses a microgrid non-destructive island detection method based on harmonic current injection and harmonic impedance measurement. The method comprises the steps of utilizing an FFT algorithm to real-timely measure a harmonic voltage, a harmonic current and a system frequency at a PCC, comparing the harmonic voltage and the system frequency with a preset voltage threshold value and a preset frequency threshold value in real time, and if the harmonic voltage and the system frequency exceed the threshold values, judging as an island state directly; otherwise, utilizing the harmonic voltage and the harmonic current to calculate an equivalent harmonic impedance amplitude and a phase angle, calculating a ratio of the harmonic impedance amplitude to the last harmonic impedance amplitude, judging whether the ratio of the harmonic impedance amplitude is greater than a proportionality coefficient or not, if so, judging whether the impedance phase angle is less than zero or not,and if not, judging as an island. According to the method, the amplitude change and phase change of the harmonic impedance are used as the island detection criteria, so that the island detection accuracy is improved, the island detection can be realized without needing to force the voltage and frequency to exceed the threshold values, and the island detection method is non-destructive.

The invention discloses an evaluation method for a coal mine impact danger pressure relief effect. According to the method, the inversion calculation of the wave velocity of a vibration wave can be carried out through the processing and analysis of a vibration wave signal, and the vibration wave velocity is in direct proportion to the stress level of a coal and rock mass, so that before a pressurerelief measure is carried out on the coal and rock mass, the wave velocity of an area to be subjected to pressure relief is subjected to inversion calculation, then a corresponding pressure relief measure is carried out, and then the wave velocity of the area after pressure relief is subjected to inversion calculation. The pressure relief effect can be evaluated by calculating the wave velocity change coefficient and the change range before and after pressure relief, a pressure relief effect evaluation index D is established, and pressure relief is considered to be valid when the D value is larger than 0.5; when the D value is within the range of 0.25-0.50, the pressure relief effect is weak, and pressure relief needs to be reinforced; and when the D value is smaller than 0.25, the pressure relief is invalid, and the pressure needs to be relieved again. The pressure relief effect of the whole impact dangerous area can be evaluated, no detection blind area exists, and the detection precision is high, so that the pressure relief effect of the whole impact dangerous area can be accurately evaluated.

The invention discloses a gene marker for detecting esophageal cancer and a use thereof and a detection method. The gene marker comprises one or more of genes of a phospholipid inositol phosphatase CXdomain containing protein 3, a sulfatase 1, a F-Box and leucine-rich repeat protein 7, a Tolloid-like protein 1, a RNA binding template single-stranded function protein 3, an ADAMTS-like protein 1, phosphodiesterase 10A, a LIM-domain ligase 2, a gamma-aminobutyric acid type A receptor protein in the gamma 3 subfamily and a sequence similar 155 family protein A. The gene marker is used for detecting esophageal cancer. The gene marker is suitable for a more extensive source of DNA samples, the detection is safe and non-invasive, the asymptomatic people have high acceptance to detection, the accuracy is high, the gene marker has high sensitivity and specificity to the early esophageal cancer, the operation is convenient, the user experience is good and the dynamic monitoring of the recurrence and metastasis of esophageal cancer is easy.

The invention discloses a precision seed sowing device work performance on-line detection device based on an electrostatic sensor and the precision seed sowing device work performance on-line detection device belongs to the technical field of agriculture automated machine detection. According to the on-line detection device, N annular metal electrodes which make up a sensor probe are inserted into the inner wall of a seed sowing tube of a precision seed sowing device and are arranged in such a way that the annular metal electrodes are parallel to the vertical direction in which seeds move, and therefore an annular metal electrode array is formed; the annular metal electrode array is connected with a signal conditioning module via a shielding wire cable, and the signal conditioning module is connected with a display module via a signal analyzing module. The signal analyzing module receives output signals of the signal conditioning module, measuring signals are subjected to wave filtering and amplifying operation, the signals are analyzed, and analysis results are display in real time via the display module. The detection device can realize non-contact type on-line detection, seed falling processes can be prevented from interference, an annular sensor is free from blind areas for detection, the detection device is convenient to install and low in price, and the detection device is applicable to precision seed sowing device work performance on-line detection in the technical field of agriculture automated machine detection.

The invention relates to the field of protection and control of micro-grids of electric power systems and particularly relates to a micro-grid island fast detection method. The method is sued for an inverter-based distributed generation (IBDG) with a PQ (power quest) decoupling control strategy; a corresponding reactive power control strategy is adopted in the method on the basis of measuring a voltage effective value UPCC and the load reactive power of a common coupling point PCC in real time through comparing the voltage effective value UPCC with the voltage effective value under a normal condition; when island determination is performed, firstly, a voltage threshold value and a frequency threshold value are predetermined, the voltage effective value UPCC is compared with the voltage threshold value, if the voltage effective value UPCC exceeds the threshold value, the PCC is directly determined be in an island state and the island detection is finished, and if the voltage effective value UPCC does not exceed the threshold value, the voltage frequency f of the PCC is compared with the frequency threshold value, the PCC is determined to be in the island state if the voltage frequency f of the PCC exceeds the threshold value. With the adoption of the detection method, the micro-grid island detection can be realized fast, and the effectiveness of the island detection can be ensured even under the existence of a plurality of inverter-based distributed generations.

The invention discloses a DC (direct-current) microgrid island detection method based on MPPT trapezoidal voltage disturbance. The method comprises the following steps: starting an MPPT strategy; setting a starting signal threshold value of disturbance; measuring an output current value when PVA operates at the maximum power, calculating the same environment coefficients of PVA with different capacities under the same illumination intensity and temperature in real time, and when the environment coefficients are greater than a set disturbance starting signal threshold value, controlling to carry out periodic trapezoidal disturbance on a PVA port voltage reference value; when it is detected that the PCC voltage value Upcc exceeds a threshold value set through a passive method, judging that an island exists, and otherwise, judging whether the change rule of the Upcc is consistent with the change rule of the calculated value Upccp of the PCC voltage under trapezoidal disturbance or not; and if so, determining that the island exists, otherwise, determining that the island is a pseudo-island. Active and passive modes are combined to carry out direct-current island detection and are matched with each other, so that no detection blind area exists.

The invention relates to a wind farm anti-islanding identification method and system based on a harmonic impedance matrix. By collecting the voltage and current of the grid-connected point of the wind farm, analyzing the magnitude of each harmonic impedance, calculating the harmonic impedance matrix modulus, and judging wind power Whether there is an island in the wind farm, so as to realize the island protection of the wind farm. Islanding is identified by using the change of circuit impedance at the grid-connected point before and after the grid is disconnected. Under grid-connected conditions, the system impedance is equivalent to the parallel connection of wind farm impedance and grid impedance. Since the main grid is close to an ideal voltage source, the system impedance is very small. After the island occurs, the main grid circuit is disconnected, and the system impedance is equal to the power station system impedance, and its value is generally much greater than the impedance when connected to the grid, so that the island state can be identified.

An embodiment of the present invention provides a passive UAV positioning method and server, the method includes: receiving spectrum information sent by at least 4 radio detectors; the spectrum information is sent by the radio detector based on the received UAV The communication signal is obtained by time-frequency conversion; based on the spectrum information, determine the time difference between the two radio detectors receiving the same communication signal sent by the UAV; The time difference of the same communication signal sent by the UAV is determined to determine the three-dimensional position information of the UAV. In this way, the detection and positioning of passive drones can be realized, without electromagnetic pollution to the environment, high positioning accuracy, no detection blind spots, and high environmental adaptability, which can be used in complex electromagnetic environments in cities.

The invention discloses a creeper tread quality test device, comprising an operation platform, a positioning device, a tension test device, a pressure test device, a traction device and a control device. The positioning device, the tension test device, the pressure test device and the traction device are sequentially arranged on the operation platform in line. The control device is arranged at one side of the operation platform and is connected with the pressure test device, the tension test device, and the traction device by a hydraulic pipeline and an electric pipeline. The invention can test creeper treads block by block, realizes production line style test process, improves test speed, and can simulate the actual stress condition of the creeper treads, thus the test result is precise and comprehensive without detection dead zone.

The invention provides a quick intelligent anti-island system and a quick intelligent anti-island method with power grid fault self-recovering capability. The method comprises the steps of a first step, establishing the main circuit of a distributed power generating grid-connected system; a second step, injecting phase angle fluctuation in the control circuit of the grid-connected system by an active phase deviation module; and a third step, based on the voltage signal of a common connecting point in the grid-connected system and a power grid frequency signal which is obtained by a phase-locked loop, realizing island detection and power grid fault self-recovering, wherein the common connecting point is the accessing position of a grid-connected filter and a local load into the power grid. The quick intelligent anti-island system and the quick intelligent anti-island method can quickly detect the island, and adding of additional hardware such as sensor is not required in the distributed power generating grid-connected system in which the phase-locked ring is used for realizing power grid synchronization. On the extreme condition that the system local load is a parallel RLC load which matches the power of the distributed power generating system, operation state of the island can be quickly and accurately detected. Furthermore no detection blind area exists and system operation efficiency can be effectively improved.

The invention discloses a DC micro-grid island detection method based on MPPT trapezoidal voltage disturbance. The steps are to start the MPPT strategy, set the start signal threshold of the disturbance, measure the output current value of the PVA at the maximum power operation, and calculate the same environmental coefficient of PVA with different capacities under the same light intensity and temperature in real time. When the environmental coefficient is greater than the set When the startup signal threshold of the disturbance is reached, the control performs periodic trapezoidal disturbance on the PVA port voltage reference value; the PCC voltage value U is detected pcc When it exceeds the threshold set by the passive method, it is judged as an isolated island, otherwise it is judged as U pcc The variation law of and the calculated value U of PCC voltage under trapezoidal disturbance pccp Whether the change rules of the islands are consistent; if they are consistent, it is an isolated island, otherwise it is a pseudo-isolated island. In the present invention, the active type and the passive type are combined to detect DC islands, and cooperate with each other, so there is no detection blind area.

The invention discloses a precision seed sowing device work performance on-line detection device based on an electrostatic sensor and the precision seed sowing device work performance on-line detection device belongs to the technical field of agriculture automated machine detection. According to the on-line detection device, N annular metal electrodes which make up a sensor probe are inserted into the inner wall of a seed sowing tube of a precision seed sowing device and are arranged in such a way that the annular metal electrodes are parallel to the vertical direction in which seeds move, and therefore an annular metal electrode array is formed; the annular metal electrode array is connected with a signal conditioning module via a shielding wire cable, and the signal conditioning module is connected with a display module via a signal analyzing module. The signal analyzing module receives output signals of the signal conditioning module, measuring signals are subjected to wave filtering and amplifying operation, the signals are analyzed, and analysis results are display in real time via the display module. The detection device can realize non-contact type on-line detection, seed falling processes can be prevented from interference, an annular sensor is free from blind areas for detection, the detection device is convenient to install and low in price, and the detection device is applicable to precision seed sowing device work performance on-line detection in the technical field of agriculture automated machine detection.

The embodiment of the present application provides a sweeping machine and an obstacle avoidance method for the sweeping machine. The sweeping machine includes a sweeping machine body, a pole plate and a control device; the pole plate is arranged on the side wall of the sweeper body, and the pole plate generates an electromagnetic field when it is in operation The control device is electrically connected to the pole plate, and is used to obtain the capacitance of the pole plate according to the change of the electromagnetic field of the pole plate, and determine whether there is an obstacle in the environment area corresponding to the pole plate according to the capacitance of the pole plate. The sweeping machine of the embodiment of the present application uses the pole plate that generates an electromagnetic field to detect obstacles, so it is not affected by the surrounding environment and light factors, and can also avoid the interference of signals sent by other sensors, which improves the accuracy of obstacle detection Spend. And because the pole plate is arranged on the side wall of the sweeper body, the electromagnetic field generated by the pole plate will not be interfered by the sweeper itself, and can be completely used to detect obstacles, thereby ensuring that there is no detection blind spot in the detection process, and improving the sweeper. reliability.

The invention relates to a gene marker for detecting liver cancer and its application for hepatitis B patients. The present invention also relates to a method for detecting liver cancer using the gene marker.