137 results about "Magnetic inductance" patented technology

A system and method capable of performing multiple types of non-invasive tomographic techniques. The system is capable, via electronic control, of detecting and imaging materials within a volume using electrical capacitance, displacement phase current, magnetic inductance, and magnetic pressure sensing. The system is also able to control the amplitude, phase, and frequency of individual electrode excitation to increase imaging resolution and phase detection. This allows many dimensions of non-invasive data to be captured without the need for multiple instruments or moving parts, at a high data capture rate.

The invention provides method to make a soft-magnetic inductance iron core by Fe-Si-Al alloy powder, including the steps: smelting Fe-Si-Al alloy - roughly crushing the cast ingot - heat treating - finely crushing into powder - annealing - grain mixing - passivating - adding insulating, binder, and mould-release agent - die forming - heat treating -coating surface. Its character: the binder is an epoxy one; the tempering after die forming is preserving the heat of the formed alloy powder at least 30 min on the condition of 600-800 deg.C nitrogen gas, argon gas or vacuum.

The invention provides a control method for an inductance parameter of a high-frequency transformer body. The control method comprises excitation inductance control and leakage inductance control of a high-frequency transformer; the rated voltage and the work frequency of the high-frequency transformer are known under the condition that the magnetic core structure and dimension are determined; the excitation inductance control method comprises the following steps: selecting a magnetic core material according to different magnetic core material magnetization characteristics and different saturation flux densities; controlling the work flux density to be Bm; and controlling an air-gap length to be lg under the condition of an open air gap of the magnetic core; and the leakage inductance control method comprises the following steps: controlling the number of turns of single-layer windings in primary and secondary windings; controlling the interlayer thickness of the primary winding, the interlayer thickness of the secondary winding and the thickness between the primary winding and the secondary winding; and changing the arrangement mode of the primary winding and the secondary winding in a separating manner, a sandwich manner and a complete coordinated transposition manner. The control method provided by the invention is used for controlling the inductance parameter, so that resonance on conversion topologies at two sides of the high-frequency transformer is achieved; and the voltage quality is improved.

The invention provides an absolute magnetic-electric rotary encoder with low cost, high accuracy and multiple circles, belonging to one of a shaft angle sensor and a displacement sensor. A main shaft supports against a main fixed bottom plate through a bearing, the front end of a pinion shaft is fixed on the main shaft through a screw, and the pinion shaft drives a circle recording component to complete a circle counting function; a bump part at the tail end of the pinion shaft is tightly assembled and fixed with an Nd-Fe-B magnet and angle position information in a single circle is obtained through a magnetic-electric induction chip fixed on a comprehensive circuit board; the comprehensive circuit board comprehensively processes the obtained number of circles and the angle position information of the single circle simultaneously to form continuous position information; the circle recording component and the comprehensive circuit board are fixed on the main fixed bottom plate through the screw and a gasket; all the elements are installed in a shell, and the whole encoder adopts an elastic installation way. With the novel magnetic-electric device with high integrity and the self-designed comprehensive circuit board, the invention simplifies installation structure, thereby being very compact and effectively reducing product axial size; and the invention adopts the magnetic-electric way, thereby greatly reducing the cost in the premise of ensuring measurement accuracy in comparison with the photoelectric way and being capable of adapting to the severe operation environment, therefore, the invention can be widely applied to the industry field, the automobile field, even the consumption field where accurate multiple-circle position measurement is required.

A position detection system that does not require calibration measurement to be performed in advance and reduces the work required for detecting a position and so on is provided. The provided position detection system includes a device having a magnetic inductance coil; a drive coil that has a position-calculating frequency near a resonant frequency of the magnetic inductance coil and generates an alternating magnetic field which acts on the magnetic inductance coil; a plurality of magnetic-field sensors that is disposed outside the operating range of the device and detects an induced magnetic field generated by the magnetic inductance coil; amplitude-component detection section for detecting amplitude components whose phase is substantially orthogonal to the alternating magnetic field from the outputs of the magnetic sensors acquired by the plurality of magnetic sensors; and position analyzing section for calculating at least one of a position and an orientation of the device on the basis of the amplitude components.

The invention comprises a high frequency inductor filter apparatus coupled with an inverter yielding high frequency harmonics and / or non-sixty Hertz output. For example, an inductor / converter apparatus is provided that uses a silicon carbide transistor to output power having a carrier frequency, modulated by a fundamental frequency, and a set of harmonic frequencies. A filter, comprising an inductor having a distributed gap core material and optional magnet wires, receives power output from the inverter / converter and processes the power by passing the fundamental frequency while reducing amplitude of the harmonic frequencies.

Provided is a three-mode rectification topological structure based on a LLC resonant converter. The primary side of a transformer comprises a full-bridge structure composed of four MOSFETs and the LLCresonant converter. The converter includes a resonant inductor, a resonant capacitor and a transformer magnetizing inductor. Without high-frequency driving, switching between a half-bridge, a full-bridge, a load and a transformer disconnection (no-load) mode is realized at the input and output sides while a light load and a heavy load are switched. Since high-frequency driving is not used, voltage ripples are reduced, and a bus voltage is controlled within the full load range. A current dead zone controller is used to achieve the purpose of current sharing. The secondary side of the transformer adopts a three-mode adjustable device. The secondary side of the transformer adopts a PWM controller to switch the heavy-load mode (full-bridge), light-load mode (half-bridge) and no-load mode, anda full-bridge rectification structure is adopted in the heavy-load mode. A half-bridge rectification structure is adopted in the light-load mode, thus achieving smooth transition from the heavy-loadmode to the light-load mode, minimizing of the output voltage ripples and synchronous switching in one-shot. In addition, the efficiency of synchronous rectification conversion is greatly raised.

The invention provides a measuring method for the stray capacitance of a large-capacity high-frequency transformer. The method includes the steps that 1, a frequency-variable excitation signal is exerted on the high-frequency transformer through a signal generator, and an oscilloscope collects a voltage signal and a current signal of a primary-side winding of the high-frequency transformer; 2, the natural resonant frequency of the high-frequency transformer is acquired according to Lissajous figures, displayed by the oscilloscope, of the voltage signal and the current signal; 3, the magnetic inductance Lm of the primary-side winding of the high-frequency transformer and the leakage inductance Ls of a secondary-side winding of the high-frequency transformer are calculated; 4, the stray capacitance of the high-frequency transformer is calculated. Compared with the prior art, no precision equipment such as an impedance analyzer and a network analyzer is needed, the stray capacitance of the large-capacity high-frequency transformer can be conveniently and effectively extracted through simple voltage and current measurement, and research on the stray parameter effect of the large-capacity high-frequency transformer and improvement on the broadband frequency characteristics of the large-capacity high-frequency transformer are facilitated.

The present invention is to provide a power converter, which includes a half-bridge circuit parallel-connected to an input voltage and having two series-connected power switches, an LLC resonant circuit formed by a resonant inductor, magnetic inductance of a primary winding and a resonant capacitor, a current-circulating circuit parallel-connected to the half-bridge circuit and having two series-connected rectifiers, and a full-wave rectification circuit connected to a secondary winding for generating an output voltage across an output capacitor. The LLC resonant circuit is parallel-connected to one of the power switches, and the line between the two rectifiers is cross-connected to the line between the resonant inductor and the primary winding. Thus, since the current-circulating circuit is able to guide current through the resonant inductor into circulation in switching moment of the power switches, parasitic capacitance of the primary winding is prevented from being overcharged by the current through the resonant inductor accordingly.

A method for identifying a traction induction motor parameter of a high-speed train is disclosed. The method comprises the steps of: running two magnetic flux linkage observers synchronously and calibrating main model parameters such as a magnetic inductance and a rotor time constant set in a controller respectively in high-speed and low-speed running regions of the traction induction motor by utilizing respective advantages of a voltage type observer and a current type observer to enable the traction induction motor to be in a full-speed running range and enable the observation effects of the two magnetic flux linkage observers to be optimal. The method for identifying the traction induction motor parameter of the high-speed train can overcome the negative influence such as temperature rise of the motor and the excitation characteristic change, and realizes high-performance traction control.

The invention discloses a high-magnetic-inductance high-frequency iron-based nanocrystalline soft magnetic alloy and a preparation method thereof. The molecular formula of the iron-based nanocrystalline soft magnetic alloy is FeaSibBcPdNbeVfMogCuh, the a, the b, the c, the d, the e, the f, the g and the h in the molecular formula correspondingly represent the atomic percentage contents of all thecorresponding alloy elements, and satisfy the following conditions that the a is greater than or equal to 75.5 and less than or equal to 77.5, the b is greater than or equal to 8.5 and less than or equal to 13.5, the c is greater than or equal to 7 and less than or equal to 10, the d is greater than or equal to 0.2 and less than or equal to 1, the e is greater than or equal to 1.0 and less than orequal to 1.7, the f is greater than or equal to 0.05 and less than or equal to 0.4, the g is greater than or equal to 0.1 and less than or equal to 1.5, the h is greater than or equal to 0.8 and lessthan or equal to 1.2, and the sum of the a, the b, the c, the d, the e, the f, the g and the h is 100. The high-magnetic-inductance high-frequency iron-based nanocrystalline soft magnetic alloy material has the advantages of excellent comprehensive soft magnetic performance, low cost, high thermal stability and the like, particularly, the high-frequency performance is good, the magnetic conductivity under the condition of 10 kHz can reach 28000 or above, a good application prospect is achieved, and the high-magnetic-inductance high-frequency iron-based nanocrystalline soft magnetic alloy material can be applied to the technical fields of high-frequency transformers, common mode chokes, wireless charging and the like.

The invention discloses an optima design method of an LLC resonant converter. The method comprises the following steps: determining transformer ratio of transformation according to a design index of an LLC resonant converter; determining the primary side turns, the secondary side turns, a winding structure and a magnetic core shape of the transformer according to the ratio of transformation of thetransformer, and initially designing a transformer; measuring a parasitic capacitance of the transformer; deducing the relation formula of switch-on loss and dead time to obtain the optimal dead timewhen the switch-on loss is minimum; determining the optimal magnetic inductance according to the optimal dead time; selecting the inductance ratio and quality factor capable of satisfying a gain condition; and obtaining a resonance inductance value and a resonance capacitance value according to the optimal magnetic inductance, the inductance ratio and the resonance frequency; and changing the airgap of the transformer to enable the magnetic inductance to be equal to the optimal magnetic inductance. Through the method disclosed by the invention, the problem that the traditional LLC resonant converter design method depends too much on the experience and is inaccurate is solved, the design result is more accurate, and can be popularized to various application occasions.

The invention discloses a preparation method of cold-rolled non-oriented silicon steel. The method comprises the following steps that 1) smelting and continuous casting are conducted into plate blanks, wherein the plate blanks comprise the following components of, by weight, less than or equal to 0.0030% of C, 2.90%-3.50% of Si, 0.15%-0.30% of Mn, 0.80%-1.5% of Als, less than or equal to 0.008% ofP, less than or equal to 0.0020% of S, less than or equal to 0.0025% of N, less than or equal to 0.0020% of Ti, less than or equal to 0.0020% of Nb and less than or equal to 0.0020% of V; 2) the castblank is heated; 3) hot rolling is conducted; 4) coiling is conducted; 5) normalizing is conducted; 6) cold rolling is conduted; and 7) annealing is conducted, wherein the temperature rising speed vmeets the condition that 20+2.15 * (WSi + WAls) is less than or equal to v, and v is less than or equal to 80-3.85 * (WSi + WAls). According to the preparation method, the high-grade cold-rolled non-oriented silicon steel can be obtained, and the steel has the iron loss P1.5 / 50 less than or equal to 2.40W / kg, the magnetic inductance B50 larger than or equal to 1.68T, and the thickness of 0.50mm.

The invention discloses an auxiliary resonant converter pole inverter with a phase-associated magnetization current bidirectional reset function. The advantage of zero-voltage switching-on of a main switch tube is realized, and the switching loss of the main switch is reduced. In addition, an auxiliary switch in an auxiliary loop realizes zero-voltage switching-on through energy storage in an excitation inductor, and the withstand voltage value of the auxiliary switch is far less than that of the main switch. Magnetization current reset is reliably realized in each switching period, so that the size of a transformer is effectively reduced. The coupling of the secondary winding of the transformer solves the overvoltage problem of auxiliary converter diodes Dc1 and Dc2. Zero-voltage switching-on of the main switch and the auxiliary switch can be realized. Efficiency and power density are effectively improved, and cost and EMI are reduced.

The invention discloses a primary inductance correction circuit applied to a flyback switching power supply. The primary inductance correction circuit mainly solves the problem that the primary magnetic inductance of a conventional transformer is deviated to influence output power. The primary inductance correction circuit comprises a clamper, a sampling control and current-voltage converter, a voltage stabilizer / isolator, a voltage-current converter, an equilibrium point controller and an oscillator. In the power tube conduction time of the flyback switching power supply, the sampling and current-voltage converter samples current flowing out of a control end, performs I-V conversion, voltage stabilization / isolation and V-I conversion on discontinuously sampled current, and outputs offset current. The clamper clamps the voltage at the control end to zero. The equilibrium point controller makes the offset current be zero when a primary magnetic inductance value is normal. The offset current is injected into the oscillator to change the frequency of the oscillator and further change switching frequency to correct an output power change caused by inductance tolerance. The primary inductance correction circuit has a simple structure, low power consumption and stable and accurate offset current.

The invention discloses a combined type brushless direct-current permanent magnet magnetic flow switching motor. The combined type brushless direct-current permanent magnet magnetic flow switching motor comprises a first motor and a second motor, wherein each of the first motor and the second motor comprises a stator and a rotor; stator teeth of the first motor and stator teeth of the second motor are arranged in pairs one by one; the excitation directions of two stator excitation sources on each pair of the stator teeth are the same or opposite; each pair of the stator teeth share one stator winding; the tooth quantity of the rotor of the second motor is three times as much as that of the tooth quantity of the rotor of the first motor; a deviation angle is formed between a first rotor tooth of the first motor and a first rotor tooth of the second motor. According to the combined type brushless direct-current permanent magnet magnetic flow switching motor, the weak magnetic inductance value of the motors is increased and the weak magnetic current is reduced; the constant power region operation capability of the motors is improved. With the adoption of a combined mode and an axial length determination method, the motor has no-load square wave counter potential, large weak magnetic inductance and a wide rotary speed operation range, and is suitable for a brushless direct-current operation mode and can realize a speed sensorless technology in a full-speed variable load range.

The invention discloses a universal motor controller based on parameter self-learning. The universal motor controller comprises a master control module, a power supply module, a motor control module, a motor parameter identification module and a power drive module connected with the motor parameter identification module and the motor control module, wherein the power supply module, the motor control module and the motor parameter identification module are in signal connection with the master control module. The universal induction motor controller can conduct automatic identification on motor parameters required for rotor field directional vector control, wherein the motor parameters include stator resistance Rs, magnetic inductance Lm, the orthogonal encoder line number Qn and rotor excitation time constant Tr; then, the motor parameters are automatically configured to a motor control module of an induction motor; in this way, the shortcomings that in the prior art, motor parameter identification operation is complex, technical requirements are high, and the application range of the controller is small are overcome, and the advantage that the controller is capable of automatically identifying the motor parameters and high in universality is realized.

The invention discloses a high-frequency center tap planar transformer in a half-bridge LLC resonant converter. Eight layers of structures are adopted, primary side windings are located in the first layer, the third layer, the sixth layer and the eighth layer, two secondary side windings are located at the second layer, the seventh layer, the fourth layer and the fifth layer respectively, primaryside additional windings comprise two rectangular additional windings, the windings at the first layer, the third layer, the fifth layer and the seventh layer are in series connection to constitute anadditional winding, the windings at the second layer, the fourth layer, the sixth layer and the eighth layer are in series connection to constitute another additional winding, two adjacent layers ofadditional windings cross with each other and are wound completely right oppositely, so that equivalent inductance Lr' and equivalent capacitance Cr' between the two additional windings replace independent resonant inductance Lr and resonant inductance Cr in a resonant network, magnetic inductance Lm is provided by a center tap planar transformer, and needed magnetic inductance values are obtainedby grinding gaps of a magnetic core; the primary side windings or the secondary side windings are located in the corresponding rectangular additional windings of the layer respectively.

The invention discloses an auxiliary resonant converter pole inverter with minimized phase-associated ZVT magnetizing current. The auxiliary resonant converter pole inverter comprises a main circuit and an auxiliary circuit, a phase-shifted full-bridge network charges an auxiliary resonance electrode inductor through an isolation transformer to realize ZVS of a main switch, and ZVS of an auxiliaryswitch is realized through energy storage in the excitation inductor. The commutation charging phase and the reset phase are locked and inversely associated, so that magnetization current bidirectional reset is realized, and the volume of the magnetic core is reduced. The improved time sequence modulation effectively reduces the follow current loss of the magnetizing current and the turn-off lossof the auxiliary switch. A phase correlation method is used for keeping the existing technology, the advantage of zero-voltage switching of a main switch tube is achieved, the switching loss of the main switch is reduced, in addition, zero-voltage switching of the auxiliary switch in an auxiliary loop is achieved through energy storage in the excitation inductor, and the withstand voltage value of the auxiliary switch is far smaller than that of the main switch. Magnetizing current reset is reliably realized in each switching period, and the problem of overvoltage of auxiliary converter diodes Dc1 and Dc2 is solved through coupling of a secondary winding of the transformer.

The invention relates to the field of manufacturing of magnetic elements, in particular to a power electronic high frequency power magnetic element. The invention provides a separable transformer with a magnetic core in a nested structure, the separable transformer comprises a high-permeability magnetic core, a skeleton sheathed on a magnetic core column, a coil wound on the skeleton and an air gap between the magnetic core, the separable transformer is characterized in that widths of magnetic cores which are respectively wound a primary coil and a secondary coil, are different, the magnetic cores which are wound the primary coil and the secondary coil of a transformer adopt nested assembly structure, and a major air gap is arranged between magnetic cores. The separable transformer provided by the invention can be used as a separable transformer of a non-contact charger, corresponding area between a primary magnetic core and a secondary magnetic core of the transformer can be effectively increased, and the separable transformer provided by the invention has the advantages of high coupling coefficient, low leakage inductance, high magnetizing inductance, uniform magnetic circuit ina magnetic core, high mechanical strength and convenience in production.

The present invention provides a current detector, wherein a first current detection circuit and a second current detection circuit are configured to a group in a preset space. The first current detection circuit and the second current detection circuit respectively comprise the following components: an annular core; a coil which winds a preset position of the core; and a magnetic inductance component which is configured in a preset position relationship with the coil in a clearance formed by the core, wherein, the coil and the clearance in the first current detection circuit and the second current detection circuit are respectively configured that the orientation of the magnetic induction component in the second current detection circuit has an angle (theta=90 DEG) relatively to the position on the core, which is coiled by the coil in the first current detection circuit, and the position with the clearance.

The invention discloses a device and method for obtaining the electric energy through a current transformer made of composite magnetic core materials. The device for obtaining the electric energy comprises the designed current transformer and an electric power obtaining circuit of the current transformer, wherein the device for obtaining the electric energy has good characteristics when a high-voltage or middle-voltage or low-voltage cable is in a small-current state and in a large-current state. When the current of an electric transmission line is small, an exciting electrical inductor of the current transformer is in resonance with an externally-arranged capacitor and the output power is improved; when the current of the electric transmission line is large, a small part of magnetic core materials of the current transformer are in a magnetism saturation condition, the function of voltage stabilization output is achieved, the overall loss of the device is prohibited, and heat-emission of a transformer body is greatly reduced. A periphery circuit of the device for obtaining the electric energy is quite simple, the electric supply stability is high, and the wide application value and the wide market prospect are achieved.

The invention discloses a power taking device based on a non-closed current transformer. The power taking device comprises the current transformer, a rectifying unit and a control unit. A diode rectifying filter unit of a traditional power taking device is replaced by an active rectifying filter unit completely formed by switching tubes. When a current of a transmission line is small, even if the power taking device is matched with a current transformer with a non-closed magnetic circuit and small magnetic inductance in use, enough output voltage and power also can be obtained and supplied to a load, so that the volume and manufacturing cost of the current transformer are reduced. When the current of the transmission line is large, the power taking device can avoid obtaining overlarge output voltage and power. The invention further discloses a control method of the power taking device. By means of the control method of the power taking device, when parameters of the transmission line, the power taking device, the load and the like change, direct current output voltage obtained by the power taking device is kept constant, so that power supplying stability of the power taking device is improved.

The invention discloses a method for measuring and calculating a transformer pi model saturation excitation curve, which comprises the steps of: using two independent voltage sources which are simultaneously arranged on one side of a transformer as excitation, wherein the two voltage sources are a direct current voltage source and an alternating current voltage source; when the transformer works in an unsaturated area, obtaining a psi-i characteristic curve of flux and current by adopting trapezoidal integral on voltage, wherein the distribution of a core loss resistance and a magnetization curve during unsaturation is accomplished by equally sharing the loss and a magnetization current, so as to describe the characteristics of excitation inductances L<m1>, L<m2> in the unsaturated area; calculating saturation inductances L<m1_s> and L<m2_s> of excitation branches so as to obtain excitation curve data of the whole saturation section; and converting the L<m1_s> and the L<m2_s> into a flux linkage psi, and distributing a saturation current to two excitation branches of an improved pi model. Through adoption of the method, a saturated excitation curve measurement experiment conditionis easy to achieve, and at the same time, the description of a measurement result and a transformer behavior can be accurate.

The invention discloses a hot-rolled edge quality control method for low-temperature and high-magnetic-inductance oriented silicon steel. The control method comprises the steps of in the process of heating the low-temperature and high-magnetic-inductance oriented silicon steel by a heating furnace high-temperature section, controlling an air-fuel ratio of an upper secondary heating section to an upper soaking section of the low-temperature and high-magnetic-inductance oriented silicon steel to be less than or equal to a first preset value, and controlling an air-fuel ratio of a lower secondaryheating section to a lower soaking section of the low-temperature high-magnetic-inductance oriented silicon steel to be less than or equal to a second preset value, wherein the first preset value isgreater than the second preset value; reducing the temperature of the heating furnace high-temperature section by 10-20 DEGC; and performing three pass of rough rolling on the low-temperature and high-magnetic-inductance oriented silicon steel by a first vertical roll and a second vertical roll, wherein the rolling speed in each pass in rough rolling is controlled at 2.6-4.8 m / s, and the best slope matching speed and backward slip coefficient between the vertical rollers E2 and R2 in each pass. The hot-rolled edge quality control method solves the technical problem of high occurrence rate of 'cake brittleness' defect at the edge of the strip.

This invention relates to magnetic inductance tomography, and in particular, to coils of a sensor / driver cail array for use in a magnetic inductance tomography apparatus, in which driver / sensor coils are used to measure the induced flux in a conductive, dielectric and permittivity body, such as the human body. The sensor / driver coil array comprises at least one layer of thin coils whose centres are arranged on a regular grid, with adjacent coils overlapped by a suitable distance to cancel inductive neighbour coupling between them.

The invention belongs to the technical field of metallurgy, and particularly relates to a preparation method of thin-strip continuous casting low-magnetic anisotropy non-oriented silicon steel. The non-oriented silicon steel comprises, by mass, less than or equal to 0.004% of C, 1.4-2.0% of Si, 0.05-0.2% of Mn, 0.1-0.4% of Al, less than or equal to 0.005% of S, less than or equal to 0.005% of N, less than or equal to 0.05% of Sn, less than or equal to 0.01% of P, less than or equal to 0.008% of Nb, V and Ti and the balance iron. The preparation method comprises the steps of smelting molten steel and carrying out thin-strip continuous casting to obtain a cast strip with the thickness of 1.5-2.5 mm; carrying out online hot rolling after the cast strip is separated from a roller with total rolling reduction of hot rolling of 50-65%, and then carrying out curling; carrying out cold rolling on the cast strip subjected to hot rolling after pickling with rolling reduction of 45-60%; and carrying out annealing on a cold rolling plate for 4-8 minutes at the temperature of 800-1000 DEG C, then cooling the cold rolling plate to the room temperature at the speed of 50 DEG C / s, and next carrying out coating treatment to obtain the thin-strip continuous casting low-magnetic anisotropy non-oriented silicon steel with the circumferential average magnetic inductance value of larger than or equal to 1.70T and anisotropy less than 5%.