278results about How to "Avoid demagnetization" patented technology

There is provided a controller for a motor capable of changing the phase difference between two rotors that can prevent demagnetization of permanent magnets or the rotors. The motor has two rotors each having a permanent magnet and phase difference changing driving means for changing the phase difference between the rotors. The controller has a demagnetization determining means for determining whether or not demagnetization of the permanent magnets of the rotors occurs during operation of the motor, and rotor phase difference controlling means for controlling the phase difference changing driving means to change the phase difference between the rotors from a current phase difference to a phase difference that results in a higher strength of a composite field of the permanent magnets if the result of determination by the demagnetization determining means is positive.

The invention discloses a radial-axial three-degree-of-freedom alternating current-direct current hybrid magnetic bearing used for non-contact suspension bearing. An axial control coil is arranged between a radial stator core and an axial stator core; an axial air gap is formed between the axial stator core and the end face of a rotor in the axial direction; three same stator core magnetic poles uniformly distributed in the circumferential direction extend from the wall of an inner cavity of the radial stator core to the axle center; same radial control coils are wound on the three stator core magnetic poles, and radial air gaps are formed between the stator core magnetic poles and the outer wall of the rotor in the radial direction; same axially magnetized annular permanent magnets are arranged between two axial sides of the radial stator core and the axial stator core; and S poles of the permanent magnets face the radial stator core, and N poles of the permanent magnets face the axial stator core. The radial-axial three-degree-of-freedom alternating current-direct current hybrid magnetic bearing integrates axial and radial functions, is only driven by a three-phase alternating current power inverter, is provided with two axially magnetized annular permanent magnets, controls the magnetic flux not to pass magnetic poles where the permanent magnets are positioned, and has the advantages of low power consumption, small volume, light weight and high bearing capacity.

A rotor for an electric rotating machine includes d-axis through holes located on respective d-axes, hollow shafts formed in both axial sides of a rotating shaft not inserted into a rotor core, presser plates mounted on both axial ends of the rotor core, cooling grooves formed in faces of the presser plates in contact with the rotor core, a plurality of presser plate refrigerant outlet holes in the presser plates, the presser plate refrigerant outlet holes of one of the presser plates having diameters different from diameters of the presser plate refrigerant outlet holes of one of the other presser plates, and a refrigerant channel formed so that a refrigerant supplied into one of the hollow shafts of the rotating shaft flows through the refrigerant channel and further through the hollow shaft wall hole of said one hollow shaft and the radial grooves of the respective presser plates.

A rotor is deployed such that the rotor becomes coaxially rotatable with a stator. A shaft is fixed onto the axis of a rotor iron-core. 1-pole constituting magnet slots are deployed into V-character pattern along an outer circumference portion of the rotor iron-core. Permanent magnets are embedded into the magnet slots. For the 1 pole, the 2 pieces of same-polarity permanent magnets are embedded into the V-character pattern. The configuration of each embedded permanent magnet is designed as follows: From the thickness of the permanent-magnet edge portion on the inner-diameter side of the rotor iron-core, which becomes the center of the V-character pattern, the thickness of the permanent magnet gradually increases toward the outer-diameter side of the rotor iron-core, which become the right and left edge portions of the V-character pattern. Simultaneously, curved lines are provided on both edge portions of the permanent magnet.

The invention relates to an electrical machine of the transversal-flux type. The machine comprises a stator and a movable element. The stator has a plurality of stator elements with magnetic flux conductors and an electric winding extending in a closed winding path through each magnetic flux conductor. The movable element comprises a number of permanent-magnet members and is movable in relation to the stator along a movement path. The winding path comprises a first current-carrying section extending along the movement path. Each magnetic flux conductor forms, together with one of the permanent-magnet members, a closed magnetic flux circuit around said current-carrying section. Each permanent-magnet member comprises a primary magnet with a magnetic direction across the movement path. Adjacently located permanent-magnet members are separated from each other by an intermediate member comprising at least one secondary magnet that has a magnetic direction essentially across the magnetic direction of the primary magnet.

A multi-gap type rotary electric machine is provided, where the machine is provided a shaft supported rotatably by a baring secured to a housing. An annular rotor is secured to the shaft and configured to rotate together with the shaft. Double stators are secured to the housing and configured to have gaps between the stators and the rotor. Relationships of:3.5<P13 / P6  (1) andP7 / P6>1  (2)are met, where P6 denotes a circumferential width of each of outer salient poles, P7 denotes a circumferential width of each of inner salient poles, and P13 denotes a circumferential width of each of the outer magnets.

There is provided a controller for a motor capable of changing the phase difference between two rotors that can prevent demagnetization of permanent magnets or the rotors. The motor has two rotors each having a permanent magnet and phase difference changing driving means for changing the phase difference between the rotors. The controller has a demagnetization determining means for determining whether or not demagnetization of the permanent magnets of the rotors occurs during operation of the motor, and rotor phase difference controlling means for controlling the phase difference changing driving means to change the phase difference between the rotors from a current phase difference to a phase difference that results in a higher strength of a composite field of the permanent magnets if the result of determination by the demagnetization determining means is positive.

The invention discloses a double-stator hybrid excitation motor with a T-type core inner stator. A center rotor is coaxially arranged in the middle of an outer stator and an inner stator. 12 T-type teeth are uniformly distributed along the circumferential direction of the inner stator yoke of the inner stator. The T-type teeth are sleeved with excitation windings. The top of each T-type tooth is near the center rotor. An inner stator slot is formed between every two adjacent T-type teeth. An arc permanent magnet is embedded fixedly between the tops of every two T-type teeth. The permanent magnets are magnetized along the tangential direction, and every two adjacent permanent magnets are magnetized in opposite directions. The inner and outer diameters of the permanent magnets are equal to the inner and outer diameters of the tops of the T-type teeth. The excitation windings are wound on the vertical parts of the T-type teeth of the inner stator, and thus, an electric excitation magnetic field connected in parallel with a permanent magnetic field is formed. The electric excitation magnetic field does not demagnetize the permanent magnets. When direct currents in different directions are fed to the excitation winding, the electric excitation magnetic field and the permanent magnetic field interact with each other to strengthen or weaken the magnetism.

The invention provides a rotor for a rotary electric machine to reduce occurrence of a magnetic flux short circuit of a permanent magnet and improve torque of the rotary rotor. A side barrier (60) is provided at a portion adjacent to a circumferential end face (32d) of the permanent magnet (32) and includes a projection barrier portion (62) projecting radially outwardly from an extension line (32bL) extending from an outer peripheral surface (32b) of the permanent magnet (32). A first air gap section (70) is provided at an area which is spaced apart from the projection barrier portion (62) and the magnet insertion hole (40) and faces a peripheral edge (62b) of a circumferentially central side of the projection barrier portion (62) with respect to the projection barrier portion and a circumferential end of the outer peripheral surface (32b) of the permanent magnet (32).

The invention relates to an electrical machine of the transversal-flux type. The machine comprises a stator and a movable element. The stator has a plurality of stator elements with magnetic flux conductors and an electric winding extending in a closed winding path through each magnetic flux conductor. The movable element comprises a number of permanent-magnet members and is movable in relation to the stator along a movement path. The winding path comprises a first current-carrying section extending along the movement path. Each magnetic flux conductor forms, together with one of the permanent-magnet members, a closed magnetic flux circuit around said current-carrying section. Each permanent-magnet member comprises a primary magnet with a magnetic direction across the movement path. Adjacently located permanent-magnet members are separated from each other by an intermediate member comprising at least one secondary magnet that has a magnetic direction essentially across the magnetic direction of the primary magnet.

A rotor is deployed such that the rotor becomes coaxially rotatable with a stator. A shaft is fixed onto the axis of a rotor iron-core. 1-pole constituting magnet slots are deployed into V-character pattern along an outer circumference portion of the rotor iron-core. Permanent magnets are embedded into the magnet slots. For the 1 pole, the 2 pieces of same-polarity permanent magnets are embedded into the V-character pattern. The configuration of each embedded permanent magnet is designed as follows: From the thickness of the permanent-magnet edge portion on the inner-diameter side of the rotor iron-core, which becomes the center of the V-character pattern, the thickness of the permanent magnet gradually increases toward the outer-diameter side of the rotor iron-core, which become the right and left edge portions of the V-character pattern. Simultaneously, curved lines are provided on both edge portions of the permanent magnet.

A 3D weark magnetic field detector is composed of three groups of magnetoelectric resistor chips with magnetic tunnel junction, which are arranged in 3D cross mode to make the magnetic sensing directios of chips perpendicular to each other. The said chip consists of substrate, two conducting films for generating bias magnetic field and reset function respectively, and induction part composed of magnetic tunnel junction, electric signal output electrode and its leading wire. Its advantages include high sensitivity and the reset and anti-damagnetizing functions.

A hybrid magnetic field controllable axial flux motor comprises two amorphous alloy stators and a rotor arrange between that two stators; The stator core of stator is divided into three parts along the radial direction, which are stator core in permanent magnet region, stator core in magnetic isolation region and stator core in electric excitation region. The armature winding of the permanent magnet region is arranged on the stator core of the permanent magnet region; The armature winding of the electric excitation region is arranged on the stator core of the electric excitation region; A permanent magnet and a ferromagnetic pole are embedded on the rotor bracket of the rotor part, respectively corresponding to the stator iron core of the electric excitation region and the stator iron coreof the permanent magnet region in the axial direction. The utility model has the advantages of simple manufacture, low loss, high power density and wide range of weak magnetic field expansion speed.

The invention discloses a high temperature resistance type solidified shell thickness electromagnetic ultrasonic frequency sweep detection method and apparatus. Internal and external sides of a continuous casting blank are correspondingly provided with an electromagnetic ultrasonic generator and an electromagnetic ultrasonic receiver. Under the effect of high power burst radio-frequency signals, the exciting coil of the electromagnetic ultrasonic generator inducts eddy current on the surface of a continuous casting blank skin layer; the eddy current furthermore generates alternating Lorentz force and ultrasonic waves under the effect of a DC bias magnetic field, wherein the ultrasonic waves penetrate the continuous casting blank and are received by the electromagnetic ultrasonic receiver. A frequency sweep circuit is in cooperation with filters of different cut-off frequencies in order to detect amplitudes and phases of transmitted waves of different sweep frequencies; through phases of two different sweep frequencies, the transition time of the electromagnetic ultrasonic waves in the continuous casting blank can be obtained, and then the thickness of a solidified shell can be calculated. The method and apparatus can effectively avoid the influence of surface high temperature radiation and water mist environment in a continuous casting production site, and meet the requirements of measuring different surface temperatures and different casting steels of casting blanks.

The invention discloses a smart power module and a variable frequency drive. The smart power module includes an upper bridge arm drive circuit and a lower bridge arm drive circuit connected with an inverter bridge separately; an overcurrent protection mode selecting circuit used for receiving and outputting overcurrent protection mode signals; an overcurrent protection time delay circuit used for receiving and outputting overcurrent protection time delay signals; an overcurrent protection circuit used for outputting overcurrent detection signals after detecting that current flowing to a load connected with the smart power module is greater than a preset current value; an inverter bridge control logic circuit used for controlling the engagement and disengagement of the upper bridge arm drive circuit and / or the lower bridge arm drive circuit according to the overcurrent protection mode signals, the overcurrent protection time delay signals and the overcurrent detection signals. According to the invention, damage of the variable frequency drive caused by that current flowing through a compressor is greater than a preset value due to factors such as pressure and the like is avoided.

The invention discloses a stator and rotor temperature field measurement system of a starting and generating integrated motor used for a hybrid vehicle. Patch-typed stator temperature sensors are arranged in different winding coil clearances of an ISG motor stator; signal output leads of the patch-typed stator temperature sensors are connected with an A / D converter by which the patch-typed stator temperature sensors are connected with a computer; patch-typed rotor temperature sensors are arranged in magnetic steel sheets of the ISG motor rotor, with signal output wires connected with signal output contacts of the external edge of the motor rotor; the signal is input into the A / D converter by a measurement probe and is then transmitted into the computer. The temperature increment curve of the stator winding and rotor magnetic steel sheets can be output by an ISG motor temperature field test when the ISG motor outputs fixed power; meanwhile, the temperature distribution of the ISG motor can be measured under the output states of various rotation speeds and various powers.

The magnetic suspension damper includes a movable rod, an outer barrel, fixed cover with central hole on the outer barrel, upper magnet with central hole in the upper mouth of the outer barrel, lower magnet in the bottom of the outer barrel, and suspended magnet between the upper and the lower magnets. All the magnets have magnetic poles set in phase, and the movable rod is made to pass through the central hole in the fixed cover and that in the upper magnet and to connect with the suspended magnet. The suspended magnet is provided with friction-reducing roller sheet for contact with inside wall of the outer barrel. The said structure makes the magnets produce mutual expelling force and the suspended magnet be affected by magnetic resistance. The present invention has high damping effect.

A brushless motor (80) for an electric power steering device (1) that assists a steering operation includes: a stator (30) having a plurality of winding sets (801,802) for a plurality of systems respectively; and a rotator (40) having a ferrite magnet (43). In the motor, a maximum current flowing without any demagnetization at high temperature is large. Hence, the torque of the motor is easily ensured at high temperature. In particular, when a failure occurs in one system, it is easy to ensure the torque of the normal system even at high temperature.

The invention relates to a composite excitation amorphous alloy axial reluctance motor, wherein the stator core is a ring-shaped modular amorphous alloy stator core composed of 6*n modules, n is a positive integer, and each module is composed of a permanent magnet on the circumferential side of a stator yoke part, a stator tooth part and a stator yoke part, and the polarities of adjacent permanentmagnets are opposite; The stator core has 6*n stator teeth on its side surface, 6*n open slots, 6*n permanent magnet poles, a rotor on the stator teeth side, 5*n ferromagnetic poles on the rotor yokepart close to the stator side, and windings wound on the stator teeth part; The stator and the rotor are located in the casing, the stator is fixed on the casing, and the rotor is fixed on the rotating shaft of the motor through the rotor bracket. The composite excitation amorphous alloy axial reluctance motor has the advantages of simple manufacture, low loss, high power density and wide range of weak magnetic field expansion speed.

The invention provides a magnetic field element. It is an object to prevent demagnetization of magnets. A magnetic field element 1a includes magnetic field portions 2 and a coupling portion 3 and is rotatable on a rotation axis 92 along a given direction 91. Each magnetic field portion 2 includes a magnet 11 and magnetic plates 21 and 22. The magnet 11 includes first and second pole faces 11a and 11b having different polarities from each other in the given direction 91. The magnetic-material plates 21 and 22 are provided on the first and second pole faces 11a and 11b, respectively. The magnetic field portions 2 are annularly arranged along a circumferential direction 93 around the rotation axis 92 and spaced in the circumferential direction 93 from one another. The coupling portion 3 is made of a non-magnetic material and couples the magnetic field portions 2 to one another.

The invention discloses a bilaterally-excited tangential magnetic steel hybrid excited brushless motor, which comprises a stator, a rotor, tangential magnetic steel, magnetic bridges, an armature winding and an excitation winding. The armature winding and the excitation winding are both AC windings and are wound around both sides of a stator slot in the stator respectively, wherein the number of pole pairs of the armature winding is equal to the number of pole pairs of the excitation winding, and is equal to the number of pole pairs of the rotor. The tangential magnetic steel is uniformly embedded in the rotor in the circumferential direction, and the magnetization directions of every two adjacent pieces of tangential magnetic steel are opposite to each other. The magnetic bridges are disposed at the top, the bottom or the middle of each piece of tangential magnetic steel. The brushless motor, by controlling the alternating current of the excitation winding in the stator, generates anexcitation magnetic field synchronously rotating with the rotor so as to realize brushless AC excitation, and adjusts the magnetic field by controlling the magnitude and direction of the excitation component in the excitation winding current, thereby improving the output capacity of the motor and also improving motor space and a material utilization rate.

An AC motor drive control device is mounted on a hybrid vehicle (200). The drive control device includes an inverter (14) which drives an AC motor (M1); and a control device (30) which controls the inverter (14) by switching its mode between a first mode and a second mode which can suppress a higher harmonic component of the output current of the inverter more than in the first mode. The control device (30) controls the inverter (14) in the first mode if the magnet temperature of a permanent magnet is lower than a first threshold temperature and controls the inverter (14) in the second mode if the magnet temperature is above the first threshold temperature.

An aspect of the present invention relates to magnetic recording powder, which comprises hexagonal ferrite magnetic particles, the hexagonal ferrite magnetic particle comprising 0.5 to 5.0 atomic percent of an Fe substitution element in the form of just a divalent element per 100 atomic percent of a content of Fe and having an activation volume ranging from 1,200 to 1,800 nm3.

An inductance element having a permanent magnet bias magnet and a bypass magnetic core comprises a coil, a magnetic core provided with at least one air gap inside the coil, partial bypass soft magnets which are form into the air gap together and a permanent magnet which is in series connection on lateral side of the air gap. According to the inductance element, the coil wraps the magnetic core; at least one air gap is formed in the magnetic core; magnetic core portions, which are close to the air gap, are in series connection with partial bypass soft magnet portions which are provided with the air gap; the permanent magnet is in series connection with an air gap opening, so that the coil magnetic branched circuit, the air gap magnetic branched circuit and the permanent magnet magnetic branched circuit are formed; the permanent magnet for the inductance element performs reverse pre-magnetic-biasing on the coil magnetic branch circuit and the output magnetic energy product of the permanent magnet is adjusted according to the size of the air gap; the direct current component of the coil current and magnetic flux density superposed through synclastic pre-magnetic-biasing of the permanent magnet are reduced, the disadvantages that in a traditional permanent magnet bias magnetic inductance element, magnetic flux density of a synthetic pre-magnetic-biasing branch is increased and inductance value is decreased, the inductance value and power density of the inductance element under certain direct current bias current are improved due to the fact that the length of partial bypass soft magnets is one fifth of the length of a main magnetic circuit.

The invention provides a fault protection device, a frequency converter and a motor driving system. The fault protection device comprises a sampling circuit, a comparison circuit and a control module,wherein the sampling circuit is used for sampling a bus voltage of the frequency converter; the input end of the comparison circuit is connected with the output end of the sampling circuit, and the comparison circuit generates a corresponding fault signal according to the abnormal bus voltage; the control module is connected with the comparison circuit, and the control module is used for controlling the frequency converter to stop outputting a PWM driving signal according to the fault signal. An abnormal bus voltage is detected through a hardware comparison circuit; and the control module istriggered to control the frequency converter to stop outputting the PWM driving signal, so that the problem that effective protection cannot be achieved due to time delay when the bus voltage is detected through software can be solved, the response speed is greatly increased, and the safety and reliability of the frequency converter in various extreme occasions are ensured.

A rotor for a rotary electric machine includes a rotor core made of magnetic material, and being in the form of a disk, and a plurality of magnet sets each including a pair of permanent magnets whose polarities are identical to each other. The magnet sets are arranged circumferentially in the rotor core so that the polarities of the magnet sets change alternately. The rotor core includes nonmagnetic portions each formed between adjacent two of the magnet sets.

Embodiments of the invention prevent demagnetization or degaussing of recorded magnetizations, even if a stray field is applied. In one embodiment, an output of a read head including a magneto-resistive effect element is inputted to a stray field detector through a DC amplifier and a DC filter. The stray field detector monitors dc components of the output from the read head, and escapes a head from above a magnetic recording medium.