109 results about "Weak field" patented technology

A motor driving apparatus includes an inverter circuit for converting an output voltage of a power supply into a three-phase AC and outputting the same to the brushless motor, a rotor position estimation unit for estimating a rotor position of the brushless motor, and an inverter control unit for controlling the inverter circuit so that the brushless motor is driven by a current based on the estimated rotor position. The inverter control unit determines an advance angle of the current supplied to the brushless motor with respect to the estimated rotor position so as to minimize a deviation between a command rpm and an actual rpm. Therefore, it is possible to perform stable weak field control for the brushless motor, independently from the input voltage of the inverter circuit, without using predetermined control variables such as table values.

An inverter for a washer performing drive control of an electric motor imparting a rotational driving force required for washing, rinsing and dehydrating operations in a full automatic washer performing the washing, rinsing and dehydrating processes continuously. The inverter comprises a control means for operating the motor with a full field in the low speed rotational region of washing, rinsing and dehydrating operations, with weak field in the high speed rotational region of dehydrating operation, and performing vector control of the output of the motor in the case of full field operation, and voltage/phase control of the motor in the case of field weakening operation.

A motor includes: a stator (12) having coils; a rotor (11), which is disposed inside the stator and has a plurality of magnets; and a magnetic path switching part (18), which is provided in the rotor (11) and switches a magnetic path of the rotor (11) to select intense field control as a forward salient-pole structure or weak field control as an inverse salient-pole structure. The magnetic path switching part (18) is formed by use of a member having magnetic anisotropy, which is arranged on a magnetic path connecting magnets (13) of the same pole and a magnetic path connecting magnets (13) of different poles in the rotor (11). By changing the magnetic anisotropy of the member, the forward salient-pole structure and the inverse salient-pole structure are switched therebetween.

An implantable medical device detects a strong static magnetic field associated with an MRI imaging instrument and operates in a safekeeping operating mode. The device (10) includes an electronic circuit for the detection/stimulation of a cardiac activity (16), a weak field sensor (22) detecting the presence of a first magnetic field of a permanent magnet being located in proximity to the device, a strong field sensor (20) detecting the presence of a second magnetic field of an MRI imaging instrument during the course of an MRI examination. The electronic circuit is placed in a safekeeping operating mode protected from the magnetic field of an MRI imaging instrument when the weak field sensor detects the first magnetic field and the strong field sensor detects the second magnetic field. The strong field sensor is a sensor that is selectively activated on detection of a magnetic field by the weak field sensor.

The present invention relates to relay device and method for the data communication between locomotive and train tail part. Based on the design of the present invention, movable repeater in special radio data transmission frequency is set on the train and strict time sequence control is performed, so as to solve the problem of powerful coverage with weak field and to realize the normal data transmission between the head and the tail of train. The device of the present invention may be used also in double track and other sections with poor radio transmission condition, and the train tail wind pressure alarm equipment has its use range expanded.

The invention relates to a method for generating the atom bean used in atom chip and relative device, wherein, the device comprises a vacuum room, an atom source, a two-dimensional micro adjusting platform, a magnetic iron and inner and outer light paths. The inner and outer light paths comprise a main laser and a re-pump laser; the vacuum room is mounted with a 1/4 wave plate reflector group with a hole in center and a direct-guide group; the magnetic light well uses the optical pump laser and the re-pump laser to prepare the atom into optimized weak field scanning state. The invention has small volume and simple structure, while it can supply the optimized weak field scanning state to the atom chip with the atom beam whose longitudinal speed is lower and uniform, transverse speed is nearly zero and density is high. The invention can be used in the guide, wave-division, interference and the Bose-Einstein Coagulation (BEC).

A vehicle drive control apparatus including a motor, a battery, an inverter having a direct current supplied from the battery, wherein the inverter converts the direct current into an alternating current and supplies the alternating current to the motor and a controller that transmits a drive signal to the inverter so as to execute a weak field control, wherein a charging current supplied to the battery, at a time when execution of the weak field control is not allowed, is set to be smaller than an overcharging current indicating a maximum value of an electric current charged in the battery.

When driving a motor, a primary side DC voltage is boosted to a secondary voltage by a converter (30c) and the voltage is converted into a 3-phase AC by an inverter (19) for supply to the motor (10m). A regeneration power of the motor is supplied to primary DC power sources (18, 21) via an inverse route. A secondary side target voltage which defines the secondary voltage to be applied to the inverter is decided according one of the following three regions: a first region where the motor is driven in a modulation mode for PWM electrical connection to at least two phases and weak field control is not performed; a third region where weak field control is performed in the modulation mode for PWM electric communication to at least two phases with a voltage smaller than a maximum voltage (Vmax) of the converter; and a second region where weak field control is performed in a 1-pulse mode for rectangular-wave electrical communication of all the phases with a voltage smaller than the maximum voltage of the converter. A converter control device (30v) decides the secondary voltage to be the secondary side target voltage.

A safety circuit for providing protection against failures that impact safety of an inverter circuit driving a Permanent Magnet Synchronous Motor (PMSM) including high and low side switches connected in a bridge and driven by a gate driver circuit during operation of the PMSM in a field weakening mode, the gate driver circuit including stages for driving the high and low side switches, the safety circuit comprising a main power supply and a back-up power supply for supplying voltage to the gate driver circuit driving the switches of the bridge of the inverter circuit, wherein if the main power supply fails to deliver adequate power to the gate driver circuit, the back-up power supply provides power to the gate driver circuit to allow the gate driver circuit to turn ON the low side switches and turn OFF the high side switches.

The invention discloses a four-dimensional antenna array used for an OAM (Orbital Angular Momentum wireless communication mode. The four-dimensional antenna array in such form is a method which can generate multiple OAM modes at the same time. The basic structure of the four-dimensional ring antenna array comprises antenna units, high-speed RF switches, a power divider and an FPGA circuit board. The maximum innovation of the invention is that as consideration is given to the influence from the existence of an OAM mode weak field area to a mode transmission distance, the provided four-dimensional ring antenna array which is a method capable of generating multiple OAM modes at the same time has obvious advantages when adopting a -1-1 switching form rather than a 0-1 switching form, and as the optimal time sequence in the -1-1 switching form is provided, each switch is guaranteed to be conducted to a state 1 within a time period according to the sequence, and the time duration taken for conducting each switch to the state 1 is same. Aiming at the influence from the weak field area to the OAM mode transmission, a relationship among the size of a receiving area, a distance between the receiving area to the antennas and an accurate calculation mode is given to bring convenience to accurate reception of a needed mode.

The present invention discloses comprehensive railway train early warning system and its operation method. The present invention works in frequency channel dissimilar to that for train scheduling signal, and has no problems of co-channel interference, radio train scheduling signal cross-talk and weak field signal covering by strong region. The system of the present invention can be used in railway multiple track and other sections with poor radio transmission condition. In addition, the railway train early warning system can send various early warning information and alarm information in broadcast mode, and may receive warning information along the line to avoid running accident and raise safety.

The invention discloses a method, a device and a system for testing the coverage performance of a network. The method comprises the following steps of: acquiring an initial time division-synchronous code division multiple access (TD-SCDMA) origination received signal code power level value and TD-to-second-generation (2G) network voice service switching frequency; computing and generating a weak-field origination ratio according to the initial TD-SCDMA origination received signal code power level value; judging whether the weak-field origination ratio exceeds a preset weak-field origination threshold value or not, and computing and generating a TD-to-2G network voice service switching frequency ratio according to the TD-to-2G network voice service switching frequency if the weak-field origination ratio does not exceed the preset weak-field origination threshold value; and judging whether the TD-to-2G network voice service switching frequency ratio exceeds a preset switching frequency threshold value or not, and determining that the network coverage performance of a base station is low if the TD-to-2G network voice service switching frequency ratio exceeds the preset switching frequency threshold value. By the method, the device and the system provided by the embodiment of the invention for testing the coverage performance of the TD-SCDMA network, the coverage performance of a TD network can be comprehensively reflected without the influence of the switching frequency, and manpower and material resources can be saved.

The invention provides a high resolution proton nuclear magnetic reonance and imaging (NMR/MRI) in microtesla magnetic fields by using high critical temperature (high-T_c) superconducting quantum interference device (SQUID) magnetometer via a flux transformer. Both the SQUID and the input coupling coil are installed inside a superconducting vessel which shields environmental noise and set the SQUID in a stable operation condition. The present invention also offers the advantages of preserving the NMR signal even if the sample is far away from the SQUID detector.

The present invention provides a control apparatus of a electric power steering apparatus which can suppress a vibration and a noise of a motor caused by a torque ripple which is generated at a tie of applying a field-weakening control to the motor or on the basis of a motor circulating current. Accordingly, the control apparatus actually measures a relation between a basic correcting current and a rotor position which can suppress the torque ripple generated at a time of applying the field-weakening control or the torque ripple based on the motor circulating current, previously, and adds a correcting current which is regulated by taking into consideration a magnitude of a weak field current of a correcting current, a magnitude of an angular velocity of the rotor or an electrical angle of the circulating current with respect to the basic correcting current, to an original current command value.

A reduced power method of writing MRAM bits is disclosed. The reduced power method includes writing MRAM bits by applying a first magnetic field having a low magnitude, then determining if the bit has switched. If not, a second magnetic field having a higher magnitude is applied. Applying magnetic fields to an MRAM bit cell is accomplished by sending a current pulse through a strip line adjacent to the MRAM bit cell. The technique can be performed for every write to an MRAM bit. Alternatively, the weaker magnetic field can be applied during system test or system initialization, and if the weaker field fails to write the bit to a desired value, the failing result is stored and each subsequent write to the MRAM bit utilizes the stronger magnetic field.

The invention provides a control device and a control method of a synchronous motor. The device comprises a d-axis current calculation portion (12) which calculates d-axis current calculation value for controlling weak field magnet based on a maximum line-to-line voltage (Vmax) calculated by a maximum line-to-line voltage calculation portion and an electric angle speed (Omega e) of a PM motor (1), and a weak field magnet control switching portion (13) which outputs any one of the d-axis current calculation value for controlling weak field magnet and a d-axis current setting value for controlling maximum torque as a d-axis current instruction value (Id*)according to the maximum line-to-line voltage (Vmax) and the electric angle speed (Omega e) of a PM motor (1). The d-axis current calculation value is calculated by the d-axis current calculation portion (12) based on the maximum line-to-line voltage (Vmax) and the electric angle speed (Omega e) of the PM motor (1) as counter electromotive force factors (Ke) of the motor parameters of the PM motor (1).

The invention discloses a system for realizing a double mode vehicular terminal and a method thereof, which are combined with the characteristic of a cross-site coverage way. A mobile terminal of a locomotive platform adopts a double mode way, and is connected with a main layer network and a back layer network at the same time respectively, and selects a better signal transmission channel according to level, quality and other performances of a received signal so as to achieve the aims of sufficiently using wireless resources of the double-layer network and improving the transmission reliability, thereby solving the problem that a weak field on an overlap region between two adjacent base stations in the main layer easily causes communication interruption when cell switching is carried out in the main layer in the prior art.

It is possible to provide a motor control device which always operates with a maximum voltage and a high efficiency even when a DC bus-bar voltage of a power conversion circuit fluctuates, and a method for controlling the motor. The motor control device includes: a d-axis and q-axis current instruction calculation unit (1, 2); a d/q conversion unit (9); a current control unit (3); a modulation wave instruction calculation unit (5); and a PWM generation unit (6). The motor control device further includes: a modulation wave instruction limit unit (13) which limits a first modulation wave instruction and generates a second modulation wave instruction; a modulation ratio saturation degree calculation unit (14) which obtains a modulation ratio saturation degree from the first modulation wave instruction and the limit value from the modulation wave instruction limit unit; and a weak field control unit (4) which corrects the d-axis current instruction value in accordance with the modulation ratio saturation degree.

The present invention is intelligent base station signal relay amplifying and transmitting device and method. The intelligent base station signal relay amplifying and transmitting device has separated donor antenna and covering antenna contacting with the base station and terminals separately and connected via relay amplifying circuit and switching circuit. The separated design of receiving antenna and the transmitting antenna makes the covering antenna capable of being installed in different position for flexible covering mode, reasonable signal covering and covering complicated area. The separated antennas have reduced interference and this makes it possible to select ever high antenna gain and raise the signal utilization. In addition, the frequency with weakest field strength is used as the frequency for the regenerating time interval in the signal relay amplifying and transmitting device for the intelligent base station, further reducting the one frequency interference to the base station.

An electrically operated drive controller includes first and second electric current command value calculation means which calculate first and second electric current command values based on a target value of torque of an electrically operated machine. The controller also includes a voltage command value calculation processing means which calculates a voltage command value based on the first and second electric current command values and an adjusting value calculation processing means for calculating an adjusting value of the first electric current command value and for performing weak field control based on the voltage command value. The first electric current command value calculation processing means adjusts the first electric current command value based on the adjusting value. The second electric current command value calculation processing means adjusts the second electric current command value based on the adjusted first electric current command value.

An embodiment of the invention provides a polarization state tunable terahertz wave emitter. A metamaterial layer is arranged on a ferromagnetic nano-film layer, and a periodic cross-shaped hollow structure is etched on the metamaterial layer; the ferromagnetic nano-film layer is driven by a sample frame to rotate, and then the metamaterial layer is driven to rotate so as to modulate the polarization state of the terahertz wave. In the embodiment of the invention, the metamaterial layer for performing polarization state modulation is integrated in the terahertz wave emitter, so that the polarization state of the terahertz wave emitted by the terahertz emitter is controllable, and the polarization state of the terahertz wave does not need to be modulated by using other external elements. The narrow-band linear polarization terahertz wave emitter, a narrow-band elliptical polarization terahertz wave emitter and a narrow-band circular polarization terahertz wave emitter integrated on chips can be realized; and in addition, the emitter with controllable weak field terahertz polarization can be realized, and the emitter also can be used for a strong-field terahertz generator with regulable polarization.