7 results about "Ac field" patented technology

The application discloses an extra-high voltage converter station of an overlapping architecture, comprising a valve hall, a converter unit, a pole line unit, a starting loop, an AC field, a bridge resistance unit, a limiting resistance unit, a metal return line unit and a grounding pole outgoing line unit; the valve hall comprises a valve tower and a converter valve, the converter unit and the pole line unit are distributed on both sides of the valve hall to form a first layer architecture; the first layer architecture further comprises the metal return line unit, and the metal return line unit is arranged in the middle of the valve hall; the starting loop, the AC field, the bridge resistance unit, the limiting resistance unit and the grounding pole outgoing line unit form a second layer architecture; the starting loop and the AC field are arranged above the converter unit, and the starting loop is connected with the AC field; the bridge resistance unit, the limiting resistance unit and the grounding pole outgoing line unit are arranged above the pole line unit; the first layer architecture and the second layer architecture are connected through a support type platform. The application splits each region of the converter station, optimizes the space overlapping structure, improves the site utilization rate and saves the occupied area.

Method for producing an at least partially amorphous metal, the method comprising the following steps: Heating a metal to a molten state; and Cooling the molten metal below its melting point, whereby the molten metal is subjected to an electric current during cooling, which is at least one of the following: electromagnetically induced in the molten metal by applying a magnetic AC field to the molten metal; and directly applied to the molten metal by at least one electrode that contacts the molten metal after the metal has reached its molten state; where cooling the molten metal includes reducing the temperature of the molten metal to ambient temperature.

The application provides a seawater motion magnetic field characteristic measuring device, which comprises a composite structure pipeline, an excitation system and a measuring system; the composite structure pipeline is used for improving the motion speed of seawater; the excitation system adopts square Helmholtz coils which are arranged on the upper and lower sides of the composite structure pipeline respectively and generate a uniform magnetic field between the coils, and the magnetic field direction is perpendicular to the cuboid pipeline; the measuring system adopts a ring-shaped magnetic core induction coil, the resonant frequency of the ring-shaped magnetic core induction coil is tuned to the fundamental wave frequency of a PWM square wave signal through parallel matching capacitors, the in-band output response is improved, and the out-of-band interference is suppressed; a preamplifier, an analog switch and a low-pass filter jointly constitute a phase-locked amplification circuit, the analog switch is controlled by a PWM signal, and the seawater motion magnetic field signal under the action of an alternating field is extracted from the interference environment.

The invention relates to the technical field of black-start auxiliary excitation, in particular to a black-start auxiliary excitation circuit and a wire connecting device. The system comprises an excitation silicon controlled rectifier bridge, an alternating current magnetic field circuit breaker and a direct current magnetic field circuit breaker which are electrically connected with the excitation silicon controlled rectifier bridge, an excitation transformer electrically connected with the alternating current magnetic field circuit breaker, and a generator and an alternating current branch which are electrically connected with the excitation transformer, the device comprises an AC power switch electrically connected with the excitation silicon controlled rectifier bridge, an excitation transformer electrically connected with the AC power switch, a first diode rectifier bridge electrically connected with the excitation transformer, and an auxiliary excitation control switch electrically connected with the first diode rectifier bridge. According to the black-start auxiliary excitation circuit, the problem that a conventional direct-current power supply cannot be adopted for auxiliary excitation in the excitation black-start process of a large generator set is solved, and the installation and maintenance efficiency of the black-start auxiliary excitation circuit is improved.

Aspects of the present disclosure generally relate to a magnetic recording device comprising a magnetic recording head. The magnetic recording head comprises a main pole, the main pole comprising a contact recessed from a media facing surface (MFS) and a contact terminal coupled to the contact, a trailing shield disposed adjacent to the main pole, a spin torque oscillator (STO) device disposed between the main pole and the trailing shield, a leading shield disposed adjacent to the main pole, the contact being disposed over the leading shield, a first alternating current (AC) source coupled to the main pole and the contact terminal, and a second AC source coupled to the trailing shield and the main pole. The first AC source is configured to generate an AC field, and the AC field is configured to generate spin waves near the contact to transfer energy to the STO device.

The invention discloses a multi-physics field calculation method for an offshore flexible direct current conversion platform and a related device, and relates to the technical field of high-voltage direct current transmission. The converter platform is divided into a valve hall, an alternating-current field hall, a direct-current field hall and a GIS equipment room according to functions, three-level calculation levels of equipment, a cabin and a platform are set, equipment-level, cabin-level and platform-level multi-physical field simulation is carried out in sequence, the simulation result of the previous level serves as the excitation condition of the next level, step-by-step geometric simplified modeling is combined, and the simulation result of the next level serves as the excitation condition of the next level. And cross-scale electricity-magnetism-heat-force multi-physics field coupling analysis is realized. The problems that in the prior art, due to the fact that the model scale is too large, full-platform simulation is not feasible, and key coupling variables are difficult to identify are solved, the simulation efficiency and precision are remarkably improved, and multi-physics field equilibrium optimization design in a compact space is supported.

The invention discloses a method and device for judging the state of a high-voltage direct-current power transmission system and a medium, and the method and device have the following beneficial effects: in the process of judging the operation state of alternating-current field equipment in the step S1, the circuit quantity of a line is compared with a preset current threshold value; the operation state of the line is further judged according to the comparison result, and whether the line forms an actual energy circulation loop or not is monitored, namely, whether the line forms the actual energy circulation loop or not can be judged by adding the auxiliary judgment condition that whether the line is in the operation state or not; therefore, misjudgment of the last circuit breaker and the last circuit by the control system in the empty charging state is well avoided.