91 results about "Field orientation" patented technology

A control system for a rotor motor, which includes a sensorless sensing module, the sensorless sensing module includes a salient polarity-based estimator module that generates a first rotor position signal based on the salient polarity and a second rotor position signal that generates a second rotor position signal based on a counter electromotive force Back electromotive force (emf) estimator module for rotor position signal. For rotor speeds below the first rotor speed, the selector selects the first rotor position signal, and for rotor speeds above the first rotor speed, selects the second rotor position signal. The rotor position sensor detects the position of the rotor and generates a third rotor position signal. The fault detection module detects a fault in the rotor position sensor, outputs a third rotor position signal when no fault is detected, and outputs one of the first and second rotor position signals when a fault is detected. An indirect field oriented control (IFOC) system controls the motor based on a selected one of the first, second and third rotor position signals.

The invention provides a wireless power transmission system and method. The wireless power transmission system includes an emission module, a reception module, a control module and a power supply module, wherein the emission module is used for receiving driving voltage to generate driving current so as to generate an alternating magnetic field, and is coupled with the reception module to perform wireless power transmission; the reception module is used for coupling with the emission module to perform wireless power transmission, and sending the feedback information to the control module; the control module is used for acquiring the amplitude and phase controlling the driving current according to the feedback information, and enabling the power supply module to work according to the acquired amplitude and phase; and the power supply module is used for receiving the amplitude and phase and adjusting the amplitude and phase so as to supply driving voltage for the emission module and generate the required driving current. The invention provides a wireless power transmission system and method, based on a three dimensional coil wave beam shaping technology. The wireless power transmission system and method can control the magnitude and direction of the magnetic induction intensity in the three dimensional space by means of control of the current amplitude flowing into the coil and the phase, enable the magnetic field to direct at the specific position, can continuously feed back information, and can reduce the system stable state error to achieve the aim of field orientation.

The invention relates to the field of a frequency conversion air conditioner, and more specifically relates to an AC-AC frequency conversion air-conditioning control method and a controller. The method comprises: obtaining a compressor target rotation speed, and detecting the three-phase voltage value of three-phase AC power; according to the three-phase voltage value, extracting the phase and the phase sequence of three-phase voltage; and according to the phase and the phase sequence of the three-phase voltage and the compressor target rotation speed, determining a q-axis current target value, the q-axis current target value participating in an FOC field orientation vector control algorithm, wherein the determined q-axis current target value is associated with a three-phase power source so as to adjust the output power of a compressor driver to enable the output power perform same-phase change with three-phase AC voltage. According to the invention, at the time when a power factor is improved, the capacitivity of an energy storage capacitor can be substantially reduced, an active PFC circuit can be avoided, and the transformation efficiency of the controller is improved.

The invention belongs to the field of cotton genetic breeding, and relates to a precocity short-fruit-spur upland cotton new-germplasm breeding method. The method includes the steps that hybridization and backcrossing are carried out with simian 2 as a female parent and gossypium klotzschianum as a male parent to obtain F1 plants and BC1F1 plants capable of normally growing; multi-generation backcrossing is carried out through simian 2 continuously, then backcross descendants are separated through selfing, zero type fruit spur families and first type fruit spur families good in prematurity and yielding ability are selected in separated groups, and precocity cotton new germplasm with the growth period of about 105 days, the zero-type or first-type fruit spurs, the compact plant type, concentrated boll opening, the good boll-setting performance, the high ginning outturn and the good fiber quality is bred through continuous multi-generation selfing and field orientation optimization in cooperation with an indoor plant laboratory test. The precocity source comes from the gossypium klotzschianum, and the hereditary basis of precocity breeding is expanded; precocity genes in the gossypium klotzschianum can be used by breeding and are of great significance in science and production.

A hair cutting device and method for facilitating and enhancing the ability to cut hair. The hair cutting device comprises a first elongated guide member that includes a first surface. The first surface includes a gravity field orientation sensor, to sense angular orientation. The first elongated guide member also includes a first end and a second end. The hair cutting device also includes a second elongated guide member that includes a first end configured to selectably couple to the first end of the first elongated guide member. The second elongated guide member further includes a second end configured to pivotly couple to the second end of the first elongated guide member. The second elongated guide member includes a plate member selectably coupleable between the first and second elongated guide members. The gravity field orientation sensor is rotatably coupled to an exterior surface of the first elongated guide member, and rotates 360 degrees.

A method and system for vector control field orientation correction of asynchronous motor. The method comprises the following steps: obtaining three-phase stator currents ia, ib and ic of an asynchronous motor and an angular velocity omega r of the motor; D-axis current isd and q-axis current isq are obtained by 3s / 2r transformation of current ia, ib and ic, and output voltage amplitude Us is calculated by voltage equation of asynchronous motor; Calculate slip angular velocity increment coefficient Kslip and slip angular velocity omega slip of asynchronous motor; Calculate d-axis control voltage of asynchronous motor shown in the description q-axis control voltage shown in the description and dq axis combined voltage shown in the descrition and according to shown in the description and shown in the description. The SVPWM space vector pulse width modulation (SVPWM-SVPWM) is processed to control the operation of the motor. The invention relates to vector control magnetic field orientation correction of asynchronous motor based on voltage observation, By calculating d, q-axis control voltage shown in the description, Thus, the operation of the motor is controlled, the problem of inaccurate orientation of the magnetic field caused by the difficulty of real-time and accurate acquisition of the rotor parameters of the motor is solved, and at the same time, the d-axis and q-axis voltage observation is taken into account, so that the accurate magnetic field positioning can be realized in the full speed range.

The invention provides a power calculation based slip estimation system. The power calculation based slip estimation system comprises a current sampling unit, a current conversion unit, a current regulation unit and a slip calculation unit, wherein the current sampling unit is used for sampling three-phase current of an asynchronous motor, the current conversion unit is used for obtaining feedback current D-axis component and Q-axis component, the current regulation unit is used for obtaining D-axis stator voltage and Q-axis stator voltage, and the slip calculation unit is used for obtaining slip according to the D-axis stator voltage, the Q-axis stator voltage, the feedback current D-axis component, the Q-axis component and a rotor time constant. The invention further provides a corresponding method. The system and the method have the advantages that the slip is estimated according to the ratio of active power to reactive power to enable rotor field orientation error caused by the rotor time constant Tr during speed regulation to become smaller, so that rotor field orientation effect of the asynchronous motor is improved effectively, and torque control precision is improved.

The invention relates to a rare earth permanent magnet material technology, and specifically introduces a rare earth permanent magnet with high magnetic performance and high resistivity and a preparation method thereof. 100 parts, 0.1-5 parts of titanate coupling agent, 1-10 parts of bisphenol A epoxy resin, and 0.2-2 parts of bisphenol F epoxy resin are uniformly mixed at 20-200 ℃ temperature field and magnetic field strength: The cured product is formed under the orientation field of 0.5-3T; the preparation process includes coupling the surface of the magnetic powder with the coupling agent, then mixing with the resin, drying and grinding, and forming under the temperature field and the orientation field. Compared with the high-end bonded NdFeB magnet, the magnetic performance of the permanent magnet of the present invention maintains a relatively high level, and the magnetic performance is not significantly decreased, and the magnet resistivity is increased by more than 10 times; there is no obvious temperature rise under a high-frequency alternating field for 1 hour.

The invention discloses a control method of a permanent magnetism direct drive wind generator system under a harmonic wave power grid voltage; the control method relates to the control of a grid sideconverter and a machine side converter of the permanent magnetism direct drive wind generator system; the control object of the grid side converter is set to inhibit the system total output of activeand reactive power 6-frequency multiplication pulsation component; the machine side converter employs a vector control strategy, and sends a permanent magnetism direct drive wind generator system stator average active power order, and a difference between the stator average reactive power and a corresponding feedback quantity to a machine side converter current reference value calculating module,thus obtaining a current reference value; rotor field orientation is employed to send the obtained machine side converter current reference value to a machine side converter current inner ring controllink, thus obtaining a machine side converter control voltage component. The control method can improve the output electric energy quality of the permanent magnetism direct drive wind generator system, thus reducing the DC bus voltage fluctuations, improving the service life, and reducing the operation cost.