Abstract: A downhole power generation includes a power generation module for providing power to a load. A turbine is driven by flow of a downhole fluid to rotate. A generator is coupled with the turbine for converting rotational energy from the turbine to electrical energy, and an AC-DC rectifier is coupled with the generator for converting an alternating voltage from the generator to a direct voltage. A power conversion circuit couples the AC-DC rectifier with the load. The power conversion circuit is configured for providing a first power to the load when the load is in a working mode and providing a second power to the load when the load is in a non-working mode. The second power is less than the first power. A downhole power generation method is also disclosed.

Abstract: A power conversion system includes one or more power conversion devices coupled to a grid connection. Each of the power conversion devices includes a power converter for converting a first multiphase current provided by the grid connection into a second current; a grid side filter coupled between the grid connection and an input of the power converter; a load side filter coupled to an output of the power converter; neutral points of the grid side filter and the load side filter connected together to form a first node; wherein the first node is not directly grounded.

Abstract: A downhole power generation system is disclosed, which includes a turbine generator system. The turbine generator system includes a turbine, a generator coupled with the turbine and having an AC-DC rectifier, and an optimized power control unit. The turbine is driven by flow of a downhole fluid to rotate. The generator converts rotational energy from the turbine to electrical energy and outputting a direct current voltage. The turbine generator system is coupled to a load via the optimized power control unit. The optimized power control unit controls to regulate an output voltage of the generator and provides a regulated output voltage to the load so that the turbine generator system has an optimized power output. An optimized power control method for a downhole power generation system is also disclosed.

Abstract: A downhole power generation system is disclosed, which includes a turbine generator system. The turbine generator system includes a turbine, a generator coupled with the turbine and having an AC-DC rectifier, and an optimized power control unit. The turbine is driven by flow of a downhole fluid to rotate. The generator converts rotational energy from the turbine to electrical energy and outputting a direct current voltage. The turbine generator system is coupled to a load via the optimized power control unit. The optimized power control unit controls to regulate an output voltage of the generator and provides a regulated output voltage to the load so that the turbine generator system has an optimized power output. An optimized power control method for a downhole power generation system is also disclosed.

Abstract: Embodiments of the present application provide a video control method, a video conference terminal and a multi-point control unit (MCU). The method comprises: performing human facial recognition on a video code stream and determining a motion quantity of the video code stream; sorting identifiers P and motion quantities R respectively corresponding to a plurality of video code streams; and selecting video code streams corresponding to video conference terminals ranked top M for synthesis and output and/or selecting a video conference terminal corresponding to a video code stream ranked first as a broadcast source.

Abstract: A drive system includes a current sensor configured to generate a first current signal representative of a current flowing in one or more electrical devices electrically coupled together through a power supply bus, a power output bus, and a common ground. The drive system also includes a voltage sensor configured to generate a first voltage signal representative of a voltage with respect to the common ground in the one or more electrical devices. The drive system further includes a ground fault detection controller configured to determine a ground fault in the one or more electrical devices based on a change in at least one of the first current signal and the first voltage signal.

Abstract: A downhole power generation system is disclosed, which includes a power generation module for providing power to a load, comprising a turbine driven by flow of a downhole fluid to rotate, a generator coupled with the turbine for converting rotational energy from the turbine to electrical energy, and an AC-DC rectifier coupled with the generator for converting an alternating current voltage from the generator to a direct current voltage, and a power conversion circuit coupling the AC-DC rectifier with the load. The power conversion circuit is configured for providing a first power to the load when the load is in a working mode and providing a second power to the load when the load is in a non-working mode. The second power is less than the first power. A downhole power generation method is also disclosed.

Abstract: A power conversion system includes one or more power conversion devices coupled to a grid connection. Each of the power conversion devices includes a power converter for converting a first multiphase current provided by the grid connection into a second current; a grid side filter coupled between the grid connection and an input of the power converter; a load side filter coupled to an output of the power converter; neutral points of the grid side filter and the load side filter connected together to form a first node; wherein the first node is not directly grounded.

Abstract: A drive system includes a current sensor configured to generate a first current signal representative of a current flowing in one or more electrical devices electrically coupled together through a power supply bus, a power output bus, and a common ground. The drive system also includes a voltage sensor configured to generate a first voltage signal representative of a voltage with respect to the common ground in the one or more electrical devices. The drive system further includes a ground fault detection controller configured to determine a ground fault in the one or more electrical devices based on a change in at least one of the first current signal and the first voltage signal.