121 results about "Stray loss" patented technology

The invention relates to an optimization design method for a high-efficiency synchronous motor of a new energy automobile. The method includes the steps that an iron loss computation model is established for the permanent magnet synchronous motor, and magnetic density changes are researched, so that magnetic hysteresis losses and no-load iron losses corresponding to different sub-harmonic magnetic fields are obtained; theoretical analysis and finite element solving are performed on load stray losses of the permanent magnet synchronous motor of the automobile in the aspects of a stator, a rotor and a permanent magnet, and permanent magnet eddy-current losses are restrained; a water cooling system of the motor is analyzed, influences on the high-efficiency range and weak magnetic performance by parameter matching are analyzed, the rotor structure form, polar trough matching and no-load counter electromotive force of the motor sample are designed, and the motor sample is tested. Through analyzing the magnetic field features, the magnetic hysteresis losses and eddy-current losses, the degree and distribution of rotor losses and the permanent magnetic eddy-current losses are accurately computed under matching between different rotor structures and polar troughs, and therefore effective measures for restraining the rotor losses and permanent magnetic eddy-current losses are found.

The invention discloses a low-uncertainty stray loss test system of a motor, which is characterized by comprising a rectifying unit, a test power supply, a simulating constant torque load and a torque / rotating speed sensor, wherein the rectifying unit respectively connects direct current obtained by bridge-rectifying alternating current commercial power to the test power supply and the simulating constant torque load; the test power supply is sequentially connected with an electrical parameter measuring control, output control and test motor after modulating the direct current into frequency converting static alternating current power supply; the simulating constant torque load is connected with a load motor after modulating the direct current into a controllable power supply of a constant torque load; and the torque / rotating speed sensor is respectively connected with a data measurement and test motor and the load motor. Compared with the prior art, the invention has the advantages of simple test system, convenient operation, high test precision and good stability, can meet an efficiency test of an efficient and superefficient motor of 0.37-375kW, has an uncertainty value lower than 0.4 percent and lays a certain foundation for China to be dedicated to research and development of the high-efficiency motor.

The present invention relates to an oil-immersed transformer overtemperature warning method under a harmonic condition. The method comprises a step of determining any harmonic current distribution and the transformer winding eddy current loss, transformer stray loss and transformer total load loss actual values of a same total current effective value, a step of determining the relation among a transformer load loss, a harmonic distortion rate and a load rate, a step of determining the relation among a transformer hottest point temperature rise, the harmonic distortion rate and the load rate, and a step of determining the threshold of a corresponding alert level. According to the method, through transforming the basic formula of the transformer harmonic loss, the relation among the harmonic loss, a harmonic current distortion rate and the load rate is obtained, thus according to the relation model between transformer temperature rise and loss, the temperature rise condition of a transformer after a certain time is derived, and the early warning of the transformer temperature rise is realized.

The invention discloses a minium loss and direct torque control method for a hybrid excitation synchronous motor; the method comprises the steps of acquiring current and voltage signals from a motor main circuit, processing the signals in a controller, calculating stator flux linkage amplitude, azimuth, electromagnetic torque, and increment of angle of attack subsequently, judging motor operation intervals according to speed, calculating stator Alpha axis voltage and Beta axis voltage according to stator flux linkage reference values under the different operation intervals, and driving a main power converter, namely an excitation power converter. The minium loss and direct torque control method for the hybrid excitation synchronous motor provides reduced motor copper loss, iron loss, stray loss, and mechanical loss, motor loading capacity and torque quick response capacity are improved, the speed adjusting range of the motor is widened, energy utilization efficiency is improved, and electricity is saved.

The invention provides a calculation method of transformer harmonic loss based on a frequency conversion property. The calculation method is characterized by comprising a direct-current resistance loss of a transformer winding under a non-linear loading condition and other stray losses of the transformer winding under the non-linear loading condition, calculating an eddy-current loss correction factor of the transformer winding, modeling the transformer by the transformer harmonic loss based on the frequency conversion property and the like, and calculating and analyzing the harmonic loss. The method provided by the invention has the advantage of accuracy of loss calculation of the transformer under the non-linear loading condition; compared with the traditional harmonic calculation method, on the basis of analyzing the frequency conversion property of a winding model, the harmonic loss is corrected by considering an overlapping calculation of an equivalent non-linear parameter of each subharmonic lower winding and the harmonic loss; therefore, the calculation method has the advantages of stronger adaptability and higher actual application value.

The invention discloses a magnetic integration type integrated filter inductance transformer which is characterized in that the transformer adopts two sets of triphase shell-type iron core structures or two sets of single-phase shell-type iron core structures; an alternating current network side winding and a load winding are only wound on a main iron core post, and filtering windings are simultaneously wound on the main iron core post and an auxiliary iron core post; the main iron core structure is the same as the traditional shell-type transformer, and the iron core magnetic circuit is closed; the auxiliary iron core adopts a magnetic circuit structure with an air gap; the number of sets of filtering windings is configured according to the filtering requirement of a system, and each set of windings are externally connected with a corresponding filtering capacitor to jointly constitute a specific subharmonic filtering branch. According to the invention, a filter reactor and the transformer are integrated, and the filtering windings can realize effective harmonic suppression through externally connecting the filter capacitor, thus one-time cost of investment is greatly reduced; and at the same time, the auxiliary iron core structure provides a circulation path for leakage magnetic flux between the primary and secondary windings, restricts the circulation direction of the leakage magnetic flux, and is beneficial to reducing the stray loss of the transformer, thus improving the operating efficiency of the transformer.

The invention discloses a luminescent device and a lens thereof. The lens comprises a incident surface and a refraction exit surface; the lens is in a slice shape; the subface of the lens is an incident surface; multi-circle ring-shape saw teeth are arranged on the top surface of the lens; these saw teeth are arranged along the direction from the center of the lens toward the inner and outer brims, and the inner lateral-faces and outer lateral-faces of the saw teeth form a refraction exit surface. A total reflection plane can also be arranged on the lateral face of the lens. The luminescent device comprises a light-source and the lens arranged in front of the light source. The invention can reduce the thickness of the lens to the largest extent, as a result, the light loss inside the lens is reduced, and the light emitting efficiency is improved. The very small thickness can realize a relatively small light-beam angle. Besides meeting the requirements of optically designed light-distribution curve, the utility model also has the advantages of very small thickness, high emitting efficiency and little stray loss; and the utility model can facilitate the design of lighting products.

The invention relates to a method and a device for measuring component stray loss based on leakage magnetic flux compensation, belonging to the technical field of electromagnetic measurement. The technical scheme is as follows: a power analyzer is connected at the side of an excitation coil in series; a voltage signal on the excitation coil is collected by the power analyzer; the loss of the excitation coil is measured; in the event of measuring the loss of the coil, a measured structure is removed and only the excitation coil and a compensation coil are connected in a measurement circuit; inthe event of measuring the total losses of the coil and the structure, the compensation coil is removed away from a measured region, and only the total losses of the excitation coil and the measured structure are measured. The method disclosed by the invention has the advantages that: the problem that the loss of the coil and the loss of the structure are hardly separated is resolved; the compensation coil is put on a movable bracket and is moved through a wheel assembly, thus the position of the compensation coil is conveniently adjusted in the measurement process; furthermore, all the structures, except the measured structure, are made of non-ferromagnetic materials, so the influence of ferromagnetic materials excluding test piece on the measurement result is eliminated.

Embodiments of the invention provide a preheating system and method of a permanent magnet synchronous motor, and a compressor, and belong to the preheating field of the permanent magnet motor. The permanent magnet synchronous motor comprises a permanent magnet and a winding coil; the preheating system of the permanent magnet synchronous motor comprises a direct current power supply, an inverter and a space vector pulse width modulation controller, wherein the direct current power supply is used for supplying power for the preheating system of the permanent magnet synchronous motor; the inverter is connected to the winding coil; the input end of the space vector pulse width modulation controller is connected to the direct current power supply, and the output end of the space vector pulse width modulation controller is connected to the inverter and used for outputting a pulse width modulation signal to the inverter, wherein the inverter is used for outputting a high-frequency three-phase alternating current voltage to the winding coil based on the pulse width modulation signal so as to preheat the winding coil and the permanent magnet under the effect of the high-frequency three-phase alternating current voltage. Therefore, in the preheating process, copper loss as well as rich and substantial stray loss are generated, so that the motor can be preheated uniformly, efficiently and rapidly.

The invention discloses a high efficiency and wide-range speed control method for a stator permanent magnet type memory motor. The method comprises the steps that the area where the motor rotating speed is located is judged through an area judging module, and different current distribution modes are adopted in different areas according to a division control strategy. In the low-speed area, a minimum value of which input power is in an AlNiCo permanent magnet flux linkage changing interval is looked up through a step-size adaptive search algorithm to achieve efficiency optimizing control of the motor, not only is the problem that a large error is generated when calculation is conducted by adopting a motor loss formula method avoided, but also inverter losses, stray losses and the like which are difficult to calculate through mathematical modeling are included in efficiency optimizing control, a difference from actual losses of a control system is decreased, and the efficiency optimizing control precision is improved. In the high-speed area, by means of the flux weakening method that a flux weakening flux linage needed in flux weakening control is obtained through a voltage difference method and a formula method, the stator permanent magnet type memory motor can achieve the high stability margin and dynamic property in a wide speed range.

The invention relates to a single-layer short isometric winding of a 48-slot 4-pole three-phase asynchronous motor, belongs to the field of the structural design of motors, and aims at providing the single-layer short isometric winding which is capable of improving motor efficiency and saving wires, and is convenient to wind and simple in embedding the wires. All the pitches, shapes and sizes of coils in the single-layer short isometric winding of the 48-slot 4-pole three-phase asynchronous motor are the same. The pitches of the coils are 9, and the wires are embedded on the single-layer short isometric winding in an overlapping method, and the single-layer short isometric winding is connected in a salient pole connection method and is suitable for manufacturing and maintenance of the three-phase asynchronous motor provided with a stator which is provided with 48 slots and 4 poles. According to the single-layer short isometric winding of the 48-slot 4-pole three-phase asynchronous motor, the length of the end portion of the winding is shortened through changing of the pitches of the coils so as to shorten the total length of the coils and reduce stator resistance, and consequently copper consumption of the stator is reduced. Meanwhile, fifth subharmonics and seventh subharmonics severely affected in a magnetic field of the motor are significantly reduced, the phenomena of magnetic leakage are reduced, and consequently stray losses are lessened. Moreover, efficiency and performance of the motor are effectively improved, and compared with an existing single-layer winding, the wires are saved by about 15% and production efficiency is improved by 30%.

The invention relates to a test method of a motor under a high-temperature and low-pressure environment and belongs to the technical field of motor characteristic testing under the high-temperature and low-pressure environment. The test method includes the following steps that: a measured motor and a standby motor are arranged in a low-pressure experimental box; the measured motor works in a motor state, and the standby motor works in a generator state; the stator current of the measured motor is gradually decreased to 0.5-times rated current from 1.5-times rated current; the stray loss of the measured motor working in the motor state is P; the measured motor works in a generator state, and the standby motor works in a motor state; the stator current of the standby motor is gradually decreased to 0.5-times rated current from 1.5-times rated current; the stray loss of the measured motor working in the generator state is P<Gs>; and the average value P<->s of the stray loss of the load of the measured motor can be obtained based on the above measured parameters and calculation results. With the test method of the invention adopted, the parameters of the motor can be detected under the high-temperature and low-pressure environment. According to the test method, and the motor can be tested under the high-temperature and low-pressure environment through adopting a double-motor back-to-back test method, and the loss values of various parameters of the motor can be calculated accurately.

The invention relates to a dynamometer-based method for measuring and analyzing the efficiency of the electric motor of an electric bicycle. The method comprises the following steps: a, a measuring device is connected with the electric bicycle; b, the output voltage of a DC stabilized power supply equals to the rated voltage of the electric motor, a rolling handle is adjusted, and the maximum open state is maintained; c, after the output voltage of the DC stabilized power supply reaches 1.25 times the rated voltage, the corresponding output voltage is gradually reduced until the undervoltage protection starts, and a measurement result is recorded; d, a power loss curve graph is drawn; the output voltage of the DC stabilized power supply equals to the rated voltage of the electric motor until the electric motor reaches the rated output power; e, the DC resistance of the electric motor is measured to obtain copper loss; f, the power loss of the controller of the electric motor is obtained according to the input power, the output power, electric copper loss, electromechanical loss, armature iron loss and stray losses of the electric motor; g, and the efficiency of the electric motor is obtained. The method is simple, economical and practical, and has the advantages of high measuring accuracy and good applicability.

The invention relates to a manufacturing process for a superhigh-efficiency brazed motor rotor, which belongs to the technical field of motor manufacturing and is applied to standard cage three-phase and single-phase asynchronous motors. The efficiency of the motor is improved, energy is saved and the efficiency is improved. The rotor of the embodiment of the invention adopts a core with parallelgrooves, and adopts rectangular copper bars. One end of each conducting bar is L-shaped, the conducting bar forms a Z shape after being inserted into the grooves, and the two ends of the conducting bar are welded to form end rings, thereby forming the whole high-efficiency brazed motor rotor. In the manufacturing process, equipment and tools are simple, and the rotor can be produced only by ordinary enterprise equipment without expensive die casting machines, die casting moulds and high-temperature copper melting electric furnaces. The manufacturing process is simple and convenient, and a barinsertion process and argon tungsten-arc welding are adopted. Insulating layers are arranged between the conducting bars in the grooves and groove walls so as to reduce stray loss produced by the medium and high frequency lateral current of the rotor and achieve favorability for reducing temperature and improving the efficiency. The efficiency of the motor can reach superhigh efficiency which is the highest of international GB18613-2006 'minimum allowable values of energy efficiency and the energy efficiency grades for mall and medium three-phase asynchronous motors'.

The invention discloses a self-starting permanent magnet synchronous motor rotor adopting a conductive sleeve. The self-starting permanent magnet synchronous motor rotor comprises an iron core, a permanent magnet, a shaft and the conductive sleeve, wherein the conductive sleeve is wrapped at the outer side of the iron core of the rotor to form a rotor starting winding; and the conductive sleeve is made of a non-magnetic good conductor material. Compared with the prior art, the self-starting permanent magnet synchronous motor rotor has the beneficial effects: 1, the equivalent air gap length of a motor is increased by means of the conductive sleeve, and the influence of magnetomotive force of stator current demagnetization on the permanent magnet is weakened; 2, the resistance of the conductive sleeve is lower and the equivalent winding of the rotor is enhanced; 3, the air gap length of the motor is increased by means of the conductive sleeve, and internal eddy-current loss and stray loss of the motor are favorably reduced; 4, the mechanical strength of the rotor can be enhanced by means of the conductive sleeve, a magnetic isolation bridge inside the rotor can be made to be narrower, and high enough utilization rate of the permanent magnet is ensured; and 5, the torque pulsation caused by slotting on the surface of the rotor during steady-state running is reduced, and vibration and noise of the motor are restricted.

The invention relates to a method for ordering power by heat of a heat supply unit based on turbine energy balance. The method comprises the following steps that according to turbine energy balance, a mathematic model of the heating steam extraction flow and industrial steam extraction flow of the heat supply unit relative to active power is obtained; according to the mathematic model, the relational expression of the minimum load to the maximum load of the unit is determined; stray losses such as valve steam leakage, heat transfer and radiation losses existing in the steam turbine flow process are considered, parameters of the relational expression of the minimum load to the maximum load are recognized and corrected by means of the least square method to obtain a precise mathematic model; data obtained from a unit DCS is transmitted to a system master station, the minimum load value and the maximum load value of the unit are obtained and transmitted to a power grid dispatching control center; integration is performed on the relational expression of the minimum load to the maximum load, an expression of the minimum electric quantity and the maximum electric quantity relative to the heat supply amount relation is obtained, according to the heat supply amount of various power plant reported units, the minimum and maximum electric generation capacities are determined, and the basis is provided for formulating an electric quantity plan.

The invention belongs to the technical field of radio frequency micro electro mechanical systems, and particularly provides a piezoelectric film bulk acoustic resonator with high frequency and high coupling coefficient, which is used for overcoming the defect of small coupling coefficient of the existing resonator unit. The sensor specifically comprises a silicon-based substrate, a bottom mass loading film, a piezoelectric film and an interdigital transducer, the bottom mass loading film, the piezoelectric film and the interdigital transducer are sequentially stacked on the silicon-based substrate, top grid-shaped mass blocks are arranged between adjacent electrode finger strips of the interdigital transducer, the long edges of the top grid-shaped mass blocks are parallel to the electrodefinger strips, and the short edges of the top grid-shaped mass blocks are flush with suspended ends of the electrode finger strips. According to the invention, the coupling coefficient and Q value ofthe resonator are effectively improved through the mass loading structure, stray loss is reduced, and the resonator is suitable for being made into a broadband filter; meanwhile, due to the adoption of a loading mass block structure, the heat dissipation performance of the resonance body is improved; in addition, the length of the top-layer mass block can be matched with that of the electrode finger strip, and the electrode finger strip adopts a length-gradient and pseudo-electrode-like structure, so that the transverse mode of the resonator is effectively suppressed.

The invention relates to a method for precisely measuring stray loss of structural components of transformers. The stray loss is measured and is calculated in a simulation manner by the aid of TEAM P21 reference models instead of the actual power transformers. The method particular includes subtracting coil loss values in load calculated values from load measured values to obtain loss values of the structural components (copper plates). The method has the advantages that the problem of excessively high deviation between loss values of copper plates and actual values due to the fact that no-load loss is subtracted from load loss of models during experimental measurement at present to obtain the loss values of the copper plates can be solved; error values can be effectively reduced by the aid of the method.

The invention relates to a 330kV-level three-phase three-winding high-impedance power auto-transformer with the function of on-load voltage regulation and belongs to the technical field of transformers. According to the technical scheme, a low-voltage winding (3), a common winding (4), a series winding (5) and a regulating winding (6) are sequentially and concentrically sleeved outside a three-phase five-pole core (2), and the low-voltage winding is serially connected with an electric reactor. An on-load tap changer is disposed at the end of a transformer oil tank. The electric reactor serially connected with the low-voltage winding is in a three-phase three-pole structure. Rectangular magnetic shields formed by stacked steel strips are disposed at upper and lower ends of a reactor winding (7), and the reactor winding is compressed with tie bolts made of low magnetism steel. The reactor winding is integrally connected with a core of the transformer through a clamp. The 330kV-level three-phase three-winding high-impedance power auto-transformer with the function of on-load voltage regulation has the advantages that short-circuit impedance voltage between high and low tension windings as well as between medium and low tension windings are achieved in such manner that the low-voltage winding is serially connected with the electric reactor, the transformer is small in size, light in weight, low in loss and the like, stray loss is reduced, and local overheating is avoided.

The invention discloses a method for measuring equivalent rotation copper consumption of a squirrel cage-type asynchronous motor. The method comprises the steps of blocking a squirrel cage-type asynchronous motor rotor, applying a three-phase symmetric voltage of a stator winding slip frequency so that a locked-rotor current is same as a stator current under a load state, and recording an input power, a stator voltage and a stator current. The rotor copper consumption of a locked-rotor test is equal to the input power subtracted from stator copper consumption, iron consumption and stray loss,and the result is equivalent rotor copper consumption corresponding to the same rotor frequency and the rotor current of the motor under the load state. According to the method for measuring the equivalent rotation copper consumption of the squirrel cage-type asynchronous motor, the rotor copper consumption of the squirrel cage-type asynchronous motor under the load running working condition is measured by an equivalent idea.

The invention relates to a method of determining magnetic conductive member stray loss, and belongs to a power transformer electromagnetic measurement technology field. According to the technical scheme of the invention, a simulation calculation way is adopted to correct a magnetic conductive member loss measurement result of an electromagnetic device. The magnetic conductive member loss is measured by adopting a conventional load-zero load way, and then the simulation calculation way is adopted to acquire a loss difference between a load working condition and a zero load working condition of an excitation coil, and at last, the loss difference is introduced in the magnetic conductive member loss measurement result, and therefore final loss data is acquired. The method is advantageous in that by adopting the simulation calculation way, a loss difference between two working conditions of a non-magnetic conductive material copper wire is calculated accurately, and the loss difference is introduced in the measurement result to correct the magnetic conductive member loss acquired by the experimental measurement, and therefore the accurate and reasonable loss data is acquired.

The invention relates to a test method of a motor under a normal-temperature and high-pressure environment and belongs to the technical field of motor characteristic testing under the normal-temperature and high-pressure environment. The test method includes the following steps that: a measured motor and a standby motor are arranged in a high-pressure sealed barrel; the measured motor works in a motor state, and the standby motor works in a generator state; the stator current of the measured motor is gradually decreased to 0.5-times rated current from 1.5-times rated current; the stray loss of the measured motor working in the motor state is P; the measured motor works in a generator state, and the standby motor works in a motor state; the stator current of the standby motor is gradually decreased to 0.5-times rated current from 1.5-times rated current; the stray loss of the measured motor working in the generator state is P<Gs>; the average value P<->s of the stray loss of the load of the measured motor can be obtained based on the above measured parameters and calculation results. With the test method of the invention adopted, the parameters of the motor can be detected under the high-pressure environment. According to the test method, and stress acts on the whole motor, and therefore, the direction of the stress borne by the motor is more diverse, and thus, the test method has a very bright application prospect.

The invention discloses a motor rotor magnetic field sine method, a rotor structure, a motor and a compressor. According to the method, a plurality of magnetic line channels are arranged in the region between a permanent magnet of a motor rotor and the outer circle of an iron core, and the circumferential size of each magnetic force line channel is set, so that the magnetic fields of outer circles of the rotors of the magnetic force line channels can be distributed close to sine. The magnetic force line channels are arranged in the region between the outer circle of the iron core of a motor rotor and a permanent magnet, and the widths of the magnetic force line channels are set according to the sine function, so that the waveform of gap flux density inside the motor of the motor rotor structure can be optimized into a relatively ideal sine curve, and the gap flux density has less low-order harmonic quantity, so that stray loss, electromagnetic noise, vibration and other adverse influences caused by low-order harmonic quantity can be effectively reduced, and the comprehensive operation index of the motor can be promoted. Furthermore, the performance of a compressor and noise and vibration indexes can be improved.

The invention discloses a method for driving a high power high speed DC brushless motor controller. The method comprises the following steps of: driving a motor by adopting a pulse width modulation method, and sampling the position information of a motor rotor by adopting a Hall sensor in a pulse width modulation interval; detecting the regularity of the position information detected by the Hall sensor, detecting the rotating speed change rate of the motor, and ignoring a detection result if the position information of the Hall sensor is detected to exceed a set range; computing the rotating speed of a rotating model by utilizing periodic information obtained by the Hall sensor, and performing phase synchronization on the rotating model by utilizing separated position information obtainedby the Hall sensor to simulate the continuous position information of the motor. In the method, a sine wave driving scheme is adopted; the method has the advantages of low switching loss, low electromagnetic radiation, high efficiency, high bus voltage utilization rate and the like; and the rotating model has high stability, thereby achieving the high stability, low noise, low stray loss and highefficiency of the motor.

A mild harmonic energy-saving transformer is provided, which relates to a power transformer based on the phase shift principle and adapted to inhibit harmonic waves and reduce energy consumption. The primary winding of the transformer is adapted to the D connection and the secondary winding is adapted to the Z connection with double outputs, that is, the secondary winding is divided into a first group of winding (A1) and a second group of winding (A2). The first group of winding (A1) comprises a first phase winding (a1), a second phase winding (b1) and a third phase winding (c1). The second group of winding (A2) comprises a fourth phase winding (a2), a fifth phase winding (b2) and a sixth phase winding (c2). The mild harmonic energy-saving transformer can inhibit the third harmonic and eliminate the fifth, seventh, seventeenth and nineteenth times harmonics; weaken the harmonic current and the harmonic current-induced coupled magnetic flux of the first and the secondary windings and the current circulation of the first side winding; reduce the stray loss of the transformer; and significantly improve the influence of the secondary harmonic on the primary power network.

The invention relates to a test method for a motor under a high-temperature and high-pressure environment and belongs to the technical field of motor characteristic testing under the high-temperature and high-pressure environment. The test method includes the following steps that: a measured motor and an accompanying motor are arranged in a high-pressure and high-temperature sealed barrel; the measured motor works in a motor state, and the accompanying motor works in a generator state; the stator current of the measured motor is gradually decreased to 0.5-times rated current from 1.5-times rated current; the stray loss of the measured motor working in the motor state is P; the measured motor works in a generator state, and the accompanying motor works in a motor state; the stator current of the accompanying motor is gradually decreased to 0.5-times rated current from 1.5-times rated current; the stray loss of the measured motor working in the generator state is P<Gs>; the average value P<->s of the stray loss of the load of the measured motor can be obtained based on the above measured parameters and calculation results. With the test method of the invention adopted, the parameters of the motor can be detected under the high-temperature and high-pressure environment. According to the test method, required parameters are measured through utilizing a motor which has the same specification as the measured motor.

The invention discloses a permanent magnet motor rotor structure. The structure comprises a rotor iron core, an outer edge of the rotor iron core is formed by connecting 2p same curved surfaces alonga peripheral direction of a rotor iron core; the curved surfaces are formed by orderly connecting multiple sections of arc parts or multiple sections of arc parts and multiple sections of line segments along the peripheral direction of the rotor iron core in a symmetric way, wherein p is positive integer greater than or equal to 1; the structure has the advantage that more adjusting variables canbe utilized to precisely optimize the waveform of the air-gap magnetic flux density, so that the waveform of the air-gap magnetic flux density approaches to sine wave, the cogging torque and ripple wave torque can be greatly weakened, the electromagnetic vibration noise of the permanent magnetic motor is reduced, and the stray loss of the permanent magnetic motor can be reduced, and the torque density and the running efficiency of the permanent magnetic motor are improved.

The invention discloses a power transformer hot spot temperature rise calculating method. The method comprises the following steps of using a finite element method to carry out magnetic field analysis, thus obtaining stray losses of each structural member of a power transformer; calculating a convective heat transfer coefficient of each structural member of the power transformer by adopting a heatflow coupling analysis method; according to the method, the hot spot temperature rise value of each structural member is determined through magneto-thermal coupling analysis on each structural member, for each structural member, the boundary condition during magneto-thermal coupling analysis is determined by utilizing the convective heat transfer coefficient of the structural member, and the stray loss of the structural member is used as a heat source during magneto-thermal coupling analysis. By applying the scheme of the invention, the calculation precision of the hot-spot temperature rise of the power transformer is improved. The invention further discloses a power transformer hot spot temperature rise calculating system, a power transformer hot spot temperature rise calculating deviceand a storage medium, wherein corresponding technical effects are achieved.

The invention discloses a high-impedance transformer coil winding device and method which are used for winding coils of a secondary iron core and a main iron core of a high-impedance transformer. The device comprises two clamping plates which are oppositely arranged in parallel, two first stop blocks which are oppositely arranged between the two clamping plates in parallel and a second stop block which is parallel to the first stop block and is arranged between the two clamping plates; the clamping plates serve as a support framework of the coil winding device and are used for limiting the displacement of core columns of the secondary iron core and the main iron core in the width direction of laminations; a space used for fixing the core column of the main iron core is formed between the first stop blocks and used for limiting the displacement of the core column of the main iron core in the thickness direction of the laminations; a space used for fixing the core column of the secondary iron core is formed between one first stop block and the second stop block and used for limiting the displacement of the core column of the secondary iron core in the thickness direction of the laminations. According to the high-impedance transformer coil winding device and method, it can be guaranteed that the offset of the core column of the secondary iron core does not occur when the high-impedance transformer coil is wound, and therefore the technical problems of waveform distortion, transformer stray losses and noise increasing which are caused by the offset of the core column of the secondary iron core are solved.

The invention discloses a rotor sheet for a motor. The rotor sheet comprises a rotor sheet body which is provided with rotor sheet grooves evenly distributed in the circumferential direction of the rotor sheet body, and the rotor sheet grooves are closed grooves. Due to the fact that the rotor sheet grooves are closed grooves, the overall strength of a die is high, the service life of the die is prolonged, and manufacturing cost of the sheet is low. Due to the fact that the rotor sheet grooves are closed grooves, a cast aluminum die middle sleeve is not needed, die cost is lowered, production efficiency is improved, product quality is guaranteed, in lathing of cast aluminum rotors, residual scraps can not be caused, stray losses of the motor is lowered, and motor efficiency is high.