Abstract: Disclosed is a system for segmented simultaneous water injection and oil recovery through double pipes in horizontal section, comprising several packers, several oil-extracting mechanisms and several water-injection mechanisms, wherein each of the packers, each of the oil-extracting mechanisms, and each of the water-injection mechanisms has an injection channel and a production channel, when several packers, several oil-extracting mechanisms and several water-injection mechanisms are combined, each of the injection channels is connected in turn, and each of the production channels is also connected in turn, the oil-extracting mechanism can extract oil through the production channel, the water-injection mechanism can inject water through the injection channel. The beneficial effects of this disclosure include: the oil in the oil production section can be produced while the water injection section is injected with water.

Abstract: The present disclosure provides a gene combination for expressing and producing terrequinone A in Escherichia coli and use thereof. The gene combination includes a tdiAS gene, a tdiBS gene, a tdiCS gene, a tdiDS gene, a tdiES gene, an sfpS gene, an ScCKS gene, and an AtIPKS gene with nucleotide sequences set forth in SEQ ID NOS:1 to 8. In the present disclosure, a recombinant engineered strain capable of producing terrequinone A having anti-cancer activity is obtained by separately constructing recombinant plasmids pC02 and pU03 through the eight genes and transforming the two recombinant plasmids into E. coli. The content of terrequinone A in a fermentation broth thereof is 106.3 mg/L, which has potential application value in the biopharmaceutical field.

Abstract: The present disclosure provides a multi-level converter with triangle topology and control method thereof, related to the technical field of multi-level converters. In the converter, n DC capacitors connected in series form a vertical edge of a triangle and are as a DC bus, n switching tubes connected in series form a bevel edge of the triangle, switching tubes each connected between a neutral point of the DC bus corresponding to each layer and a point for connecting the switching tube on the bevel edge form a horizontal edge. Each time the layer is expanded by one, the number of levels increases by one. When a voltage across each capacitor is E, an AC output terminal Xn may output a total of n+1 levels.

Abstract: The present disclosure provides a multi-level converter with triangle topology and control method thereof, related to the technical field of multi-level converters. In the converter, n DC capacitors connected in series form a vertical edge of a triangle and are as a DC bus, n switching tubes connected in series form a bevel edge of the triangle, switching tubes each connected between a neutral point of the DC bus corresponding to each layer and a point for connecting the switching tube on the bevel edge form a horizontal edge. Each time the layer is expanded by one, the number of levels increases by one. When a voltage across each capacitor is E, an AC output terminal Xn may output a total of n+1 levels.

Abstract: The present disclosure provides a single carrier based multilevel modulation method, a single carrier based multilevel modulation device, and a storage medium. In each control period, a modulated wave value corresponding to each of n switch pairs is obtained according to a reference voltage to obtain n modulated wave values, a triangular carrier having an amplitude of n is generated and compared with each of the n modulated wave values to obtain control signals for each of the n switch pairs, and for each phase, the control signals are input to the corresponding switch pairs of the phase bridge.

Abstract: The present disclosure provides a single carrier based multilevel modulation method, a single carrier based multilevel modulation device, and a storage medium. In each control period, a modulated wave value corresponding to each of n switch pairs is obtained according to a reference voltage to obtain n modulated wave values, a triangular carrier having an amplitude of n is generated and compared with each of the n modulated wave values to obtain control signals for each of the n switch pairs, and for each phase, the control signals are input to the corresponding switch pairs of the phase bridge.

Abstract: A method and a device for voltage balancing of DC bus capacitors of an NPC four-level inverter are disclosed. The method includes: determining an optimal zero-sequence voltage, determining an actual reference voltage of each phase based on the optimal zero-sequence voltage; comparing respectively three preset carrier signals with the actual reference voltage of each phase to obtain three first control signals; determining three duty-cycle adjustment values based on a voltage of the intermediate bus capacitor; adjusting correspondingly the three first control signals based the three duty-cycle adjustment values to obtain three second control signals; inputting correspondingly the three second control signals to three first switches of an upper bridge corresponding to each phase; and inputting correspondingly complementary signals of the three second control signals to three second switches of a lower bridge corresponding to each phase.

Abstract: A method and a device for voltage balancing of DC bus capacitors of an NPC four-level inverter are disclosed. The method includes: determining an optimal zero-sequence voltage, determining an actual reference voltage of each phase based on the optimal zero-sequence voltage; comparing respectively three preset carrier signals with the actual reference voltage of each phase to obtain three first control signals; determining three duty-cycle adjustment values based on a voltage of the intermediate bus capacitor; adjusting correspondingly the three first control signals based the three duty-cycle adjustment values to obtain three second control signals; inputting correspondingly the three second control signals to three first switches of an upper bridge corresponding to each phase; and inputting correspondingly complementary signals of the three second control signals to three second switches of a lower bridge corresponding to each phase.