33results about How to "Adjust voltage" patented technology

The invention discloses a driving circuit and a driving method of a permanent magnet synchronous motor. By sampling the voltage and current information of one phase of the permanent magnet synchronous motor, the back EMF information of the corresponding phase is estimated, and then the back EMF information will be characterized The angle difference between the first voltage signal of the information and the current sampling signal representing the current information is calculated to obtain an angle difference signal, and the angle difference signal is used to adjust the amplitude of the first horseshoe-shaped modulation wave to control the rotation of the rotor The phase of the current coincides with that of the first horseshoe-shaped modulation wave, so that the torque produced per ampere of current is maximized. The invention obtains the counter electromotive force information through estimation, does not need complex coordinate transformation, and has simple algorithm and easy realization. In addition, the present invention changes the phase difference between the back electromotive force of the motor and the phase current by adjusting the current of the motor, so as to realize maximum torque control, and the efficiency of the motor is high.

The invention relates to a pavement construction method which comprises the following steps: (1) paying off and leveling; (2) arranging a base layer and flattening the base layer; (3) arranging a heat insulating layer on the base layer; (4) laying electrical heating material on the heat insulating layer; (5) paving a concrete bottom layer on the heat insulating layer; (6) spraying an epoxy asphalt waterproof adhesive layer on the concrete bottom layer; and (7) paving a concrete top layer on the waterproof adhesive layer.

The invention discloses a method for constructing road surfaces.The method includes steps of (1), carrying out paying off and leveling; (2), arranging basement layers and leveling the basement layers; (3), arranging heat-insulation layers on the basement layers; (4), laying electric heating materials on the heat-insulation layers; (5), paving concrete bottom layers on the heat-insulation layers; (6), spraying epoxy asphalt waterproof bonding layers on the concrete bottom layers; (7), paving concrete top layers on the waterproof bonding layers.The electric heating materials are numbered when laid and are divided into first arrays and second arrays; the heights of the electric heating materials of the second arrays are lower than those of the electric heating materials of the first arrays when the electric heating materials are laid.

The embodiment of the invention discloses a liquid crystal lens and a display device provided with the liquid crystal lens and belongs to the field of a display technology. The liquid crystal lens solves the technical problem that an existing liquid crystal lens can not be moved anywhere. The liquid crystal lens comprises a first substrate, a second substrate and a liquid crystal layer arranged between the first substrate and the second substrate. A first electrode is arranged on the first substrate, and a second electrode is arranged on the second substrate. The first electrode and the second electrode are both transparent planar electrodes. The electrical conductivity of the first electrode in the longitudinal direction is higher than that of the first electrode in the horizontal direction. The liquid crystal lens can be applied to the display devices such as LCD televisions, LCDs, digital photo frames, mobile phones and tablet personal computers.

The invention discloses a 35 kV direct-hanging SVG system and a PLC logic control method thereof. The control system uses a method of configuration monitoring + PLC+ controller. The configuration monitoring is mainly responsible for issuing various control parameters, whole machine protection set values, and displaying operation states and faults. The PLC is mainly responsible for whole machine operation flow. The main controller uses DSP adding FPGA architecture. The 35 kV direct-hanging SVG does not need a step-down transformer, and is directly hung on a 35 kV power grid. The system can adapt to hundred-trillion-level fast dynamic compensation of a power grid, adjusts voltage of a long-distance transmission line, reduces power transmission loss, improves transmission capacity, and improves transient voltage maintenance level. The system can be widely used in wind power stations, photovoltaic power stations, etc.

The invention provides an electric power generating system and a control method thereof, and the system and method provided by the invention are used for solving the defect that the existing electric power generating system which centers on a synchronous motor has less possibility of maintaining constant frequency output when a prime motor operates in a speed change mode. According to the invention, the frequency of an alternating current excitation power supply which is output by a first frequency conversion device is controlled to be always equal to the slip frequency of a first motor according to the preset frequency of three-phase alternating current which is output according to the rotation speed of a first motor rotor and a first motor stator winding so as to adapt to the variations of the rotation speed of the first motor, thus the variations of the rotation speed of the first motor are matched with the optimal rotation speed of the prime motor, the speed change constant frequency output of the electric power generating system is realized, simultaneously the efficiency of the electric power generating system is improved, and the static state and transient state stability of the electric power generating system are improved obviously.

The invention discloses an ultrashort pulse laser induced plasma assisted electric spark compound processing device and an ultrashort pulse laser induced plasma assisted electric spark compound processing method under action of a magnetic field and belongs to the field of laser processing and electric spark compound processing of special processing. The device compounds a laser induced plasma processing unit, an electric spark processing unit and a compound magnetic field unit together organically. The laser induced plasma processing unit comprises an ultrashort pulse laser, a laser power supply, a water cooler and a light path conversion assembly. The compound magnetic field comprises a direct current excitation power supply and an annular electromagnet. The electric spark processing unitcomprises a five-degree-of-freedom precision platform for controlling a workpiece to move expectedly. The device and the method provided by the invention sole the problem that it is hard to process alow conductivity material and achieve cross-dimension processing and the processed surface is not enough high in quality in the electric spark processing technology, and have a very wide applicationprospect.

The invention provides a liquid crystal display panel, which mainly includes a thin film transistor array substrate, a color filter substrate, a frame glue and a liquid crystal layer. Among them, the thin film transistor array substrate includes a substrate, multiple pixel structures, multiple scanning lines, multiple data lines and a light-shielding pattern. The scanning lines and data lines are arranged on the substrate to control the operation of the pixel structure. The light-shielding pattern is arranged on the edge of the panel, straddles the scanning wiring and the data wiring, and is electrically insulated from the scanning wiring and the data wiring. The sealant is arranged between the thin film transistor array substrate and the color filter substrate, and corresponds to the light-shielding pattern. The liquid crystal layer is arranged between the color filter substrate, the thin film transistor array substrate and the frame glue.