64 results about "Nonlinear inductance" patented technology

The invention discloses a single-phase three-winding autotransformer model taking nonlinear influences of excitation impedance into consideration, which belongs to the technical field of transformers. The single-phase three-winding auto-transformer model comprises a basic electric circuit and magnetic circuit equation of a single-phase three-winding step-down autotransformer, an equivalent circuit of a single-phase three-winding autotransformer, an equivalent circuit of a single-phase three-winding step-up autotransformer, an expression of an excitation impedance zm and an expression of the single-phase three-winding autotransformer model taking account of the nonlinear influences of the excitation impedance. The autotransformer model not only takes account of the magnetic coupling between a high-voltage winding and a medium-voltage winding but also takes account of the electrical relationship, and the result of a harmonic characteristic simulation performed by the single-phase three-winding autotransformer model is more actual than that of the harmonic characteristic simulation performed by a common three-winding transformer instead of the three-winding autotransformer. The excitation impedance not only comprises generally non-ignorable nonlinear inductance reflecting iron core saturation characteristics, but also takes account of the nonlinear resistance reflecting iron losses, and the harmonic characteristic of a transformer can be analyzed more accurately by using the excitation impedance.

The invention discloses a bidirectional DC-DC converter and a control method thereof. The converter is mainly applied to an aerospace power system, a shipboard power supply, a DC motor driving system, a storage battery system, a DC uninterruptible power system and a compound energy storage system of a vehicle. The method of the invention is applied to the bidirectional DC-DC converter which comprises an input side full bridge circuit and an output side full bridge circuit. The method comprises the steps that when the primary side current of a transformer is equal to the critical current of a nonlinear inductor, the inductance of the nonlinear inductor changes suddenly, the slope of the primary side current change of the transformer is increased, the primary side current of the transformer is raised, the reset time is reduced, and the slope of the primary side current change is increased; through internal shift comparison, the voltage of a primary side of the transformer is zero, and the cycle energy of the bidirectional DC-DC converter is zero. The efficiency of the bidirectional DC-DC converter is greatly improved, and the structure and control of the converter are simple and easy to realize.

The invention discloses a position-sensor-free control method suitable for four-quadrant operation of a switch reluctance motor, and belongs to a switch reluctance motor control method. The position-sensor-free control method comprises the following steps of constructing a simplified inductance model according to a fourier series expression of inductance of the switch reluctance motor; fitting a function relation in which an inductance model parameter is changed along with phase current by measuring inductances at three special positions of the switch reluctance motor at different phase currents on line, and constructing a non-linear inductance model of the switch reluctance motor; deriving an analysis formula for estimating a position of a rotor of the switch reluctance motor through phase inductance according to the non-linear inductance model; and when the motor runs, detecting the phase current and phase voltage in real time, estimating an excitation phase magnetic chain according to a voltage equation to obtain excitation phase inductance, calculating the current position of the rotor according to the estimation analysis formula by using the derived position of the rotor, and realizing sensor-free running control over the switch reluctance motor according to the estimated position of the rotor. The algorithm is simple, small in calculated amount, favorable for real-time implementation of a micro controller and higher in position estimation precision.

The invention discloses a multiple outputs direct current-direct current converter which can improve across adjustment performance, thereinto nonlinear inductance element which is used as drain inductance of output coupling inductance is set on output path of at least one secondary circuit of first winding which is coupled to the transformer. The change of inductance value of the nonlinear inductance element is revered with the current of the nonlinear inductance element. When load on an output end of the direct current-direct current converter is changed, the output path with bigger load current can generate smaller drain inductance and the output path with smaller load current can generate bigger drain inductance, so current in output end of the direct current-direct current converter can be balanced.

A transmon qubit comprising a plate capacitor comprising a first plate (202) and a second plate (203) wherein the first plate is disposed opposite to at least a part of the second plate, wherein the first plate and the second plate are connected via a nonlinear inductance element (304), and a capacitance (205) formed between the first plate and the second plate, wherein the first plate and the second plate are configured to form a vacuum gap capacitor.

An inverter output current passes from an inverter phase output, through a non-linear inverter side inductor, and into a line that connects through a grid side inductor to a grid phase. An inductance of the inverter side non-linear inductor is estimated, a current passing through the grid side inductor is estimated, and a current through the inverter side inductor is measured. An inverter feeding the inverter output is controlled using a weighted average of the estimated current through the grid side inductor and the inverter side inductor current measurement, applying a weighting using the estimated inductance.

A control method for constant torque of a switched reluctance motor is disclosed, belonging to the field of motor test. The inventive aims at solving the problem that torque pulsation is large when a conventional speed and current double closed-loop control manner is used to control the torque of the switched reluctance motor. The inventive method comprises the steps that: in order to ensure that the switched reluctance motor outputs constantly in accordance with the set torque, a reference current is given at first, a transient inductance corresponding to the reference current is then obtained by inquiring an universe nonlinear inductance curve family data sheet of the switched reluctance motor, an inductance slope corresponding to the transient inductance is further obtained, an output phase winding current is calculated in accordance with the formula i=square root (2T/K<L>), and whether the difference value between the phase winding current and the reference current is in a permissible error range is judged, if not, the phase winding current, which is calculated, is assigned to the reference current and is recalculated in accordance with the method, multiple circulations are implemented until the condition is satisfied, and the output phase winding current is loaded at two ends of the phase winding of the switched reluctance motor to realize control of the constant torque of the switched reluctance motor.

A global nonlinear inductance test method of a switched reluctance motor belongs to the motor test field, aiming at solving the problem of big error of the inductance of the switched reluctance motors measured by traditional LCR meters. In the method, the position of a rotor of the switched reluctance motor is changed and fixed by a stepping motor; step voltage is loaded on a phase winding of the switched reluctance motor; a computer collects the current value of the phase winding via a current sensor; the collecting cycle is controlled by the computer programs; instantaneous inductance corresponding to the current values of different phase windings is computed when the position of the rotor is a certain fixed angle; the stepping motor is controlled to rotate according to the stepping angle; the relation between the current of the inductance is measured by above method under the condition of different positions of the rotor and finally the global nonlinear inductance information is obtained. The method is used for measuring the global nonlinear inductance of the switched reluctance motors.

The invention discloses an active valley-filled alternating-current and direct-current converter improving power factor efficiency. The active valley-filled alternating-current and direct-current converter is composed of a diode rectifier bridge (1), a non-linear LC network (2) and a subsequent switch power converter (3). The non-linear LC network (2) is powered by the output of the diode rectifier bridge (1), and the subsequent switch power converter (3) is powered by the output of the non-linear LC network (2). The non-linear LC network (2) is composed of an inductor L, an energy storage capacitor C, a resonance capacitor Cr and a switching network. The switching network is formed by connecting a bilateral switch K and a diode D in parallel. A charging circuit of the energy storage capacitor C is composed of the diode rectifier bridge (1), the inductor L, the diode D, the resonance capacitor Cr and the energy storage capacitor C. A discharging circuit of the energy storage capacitor C provides energy for the subsequent switch power converter (3) through the energy storage capacitor C and the bilateral switch K.

The invention discloses a transformer electromagnetic transient simulation modeling method based on PSCAD/EMTDC (power system computer aided design/ electromagnetic transients including DC) software. The method comprises the following steps of (1) creating a variable inductance element control model in a Graphic window of PSCAD/EMTDC; (2) creating a user parameter input interface in a Parameters window; (3) respectively compiling data preprocessing codes, hysteresis main loop cluster fitting codes and hysteresis sub loop cluster fitting codes in Computer and DSDYN segments of a Script window, and outputting an inductance value for controlling the variable inductance element; (4) building a nonlinear inductance element test model for describing hysteresis characteristics of ferromagnetic materials in a main window, building a model with the same system parameters in ATP-EMTP (alternative transients program-electromagnetic transients program) software, and performing simulation and result comparison; (5) connecting a nonlinear inductance element to the high-voltage side of a UMEC (unified magnetic equivalent circuit) transformer model in parallel in the main window, forming a transformer electromagnetic transient simulation model considering the hysteresis characteristics, and performing simulation result comparison in a manner like that in the step 4. The transformer electromagnetic transient simulation modeling method overcomes the defect that a transformer only considers saturation characteristics but does not consider the hysteresis characteristics in the PSCAD/EMTDC.

The invention provides a distinguishing method of PT ferromagnetic resonance, which comprises the following steps of: 1, converting a distribution network system containing PT into a simple single-phase serial-parallel connection circuit structure; 2, establishing a mathematical model of nonlinear inductances of a capacitor, a resistor and the PT in the equivalent circuit of the step 1; establishing a time-varying vector based state equation of the nonlinear inductances of the capacitor, the resistor and the PT in the equivalent circuit; 4, converting the state equation in the step 3 into a vector relation between the nonlinear inductances of the capacitor, the resistor and the PT and a magnetic flow; 5, solving the relation among the PT, the total voltage at two ends of the capacitor and the magnetic flow according to the time-varying vector based state equation, and converting vector relation into relation between effective values; 6, defining an energy function and calculating stability margin and disturbance quantity of the distribution network system; and 7, distinguishing the PT ferromagnetic resonance. The PT ferromagnetic resonance is distinguished by comparing the stability margin with the disturbance quantity, which has guidance for operators.

The invention relates to a method for estimate that rotor position of switched reluctance motor. Based on the inductance characteristics of the saturated main magnetic circuit, A rotor position estimation strategy with saturated nonlinear inductance interval avoiding detection coil is proposed, Considering the problem of phase shift caused by analog filtering in the process of indirect acquisitionof inductance information of detection coil, a phase shift compensation algorithm is designed according to the phase shift theory to eliminate the position estimation error and further improve the position estimation accuracy. Through the above design, the detection coil technology can meet the requirements of dynamic operation under various load conditions, and can also achieve accurate positioning of the static initial position, to achieve frequent non-reverse starting of the motor. Therefore, it is helpful for its application in aerospace starter generators, electric vehicle drive motors and other applications where the reliability requirements are extremely high and the operating conditions are relatively harsh.

The invention discloses a dual-magnetic-gap magnetic path system and loudspeaker with the same. The dual-magnetic-gap magnetic path system comprises T iron, an annular magnet, a first annular washer, an annular support member and a second annular washer. The annular magnet and the annular support member are arranged on a circular base plate of the T iron, and the first annular washer is arranged on the annular magnet; the second annular washer is arranged on the annular support member; and the first annular washer and the second annular washer form a first magnetic gap, the second annular washer and the side wall of a column core form a second magnetic gap, the first magnetic gap is used for suspending a first voice coil, and the second magnetic gap is used for suspending a second voice coil. According to the invention, the mutual induction electromotive force of the voice coils can be reduced, high-frequency replay distortion is improved, through introduction of the annular support member, change of nonlinear inductance of the coils can be reduced, and harmonic distortion is reduced.

The invention discloses a nonlinear inductor loss measuring method based on direct current bias, which is mainly used for solving the problem of low speed in solving the loss of a nonlinear inductance core in the prior art. The nonlinear inductor loss measuring method is realized by the following steps of: firstly, measuring the size of a measured inductor to obtain a physical parameter of the inductor; establishing an inductance model in finite element software, and carrying out grid division on the inductance model; applying voltage drive on the inductance model to ensure that a current value in the inductance model is equal to a set bias current; after the current in the inductance model reaches the bias current, applying a periodic signal to the inductance model to ensure that a current waveform in the inductance model is consistent with the actual current; and calculating the loss density of a magnetic core according to a Stienmetz equation, and finally summing to obtain the loss of the whole inductor magnetic core. The nonlinear inductor loss measuring method has the advantages of high measurement speed and high precision and can be used for circuit design.

The invention belongs to the technical field of inductance test and specifically relates to a switched reluctance motor global non-linear inductance test device and test method. Provided is the switched reluctance motor global non-linear inductance test device and test method which can combine motor saturation characteristics and inductance nonlinearity to accurately measure motor saturation and inductance, thereby reducing motor performance evaluation errors. The test device comprises a test platform (1), a tested switched reluctance motor (2), a DC voltage source (3), a computer (4), a current sensor (5), a voltage sensor (6), a stepping motor (7), a stepping motor controller (8) and a linkage mechanism (9), wherein the test platform (1) is provided with the tested switched reluctance motor (2), the DC voltage source (3), the stepping motor (7) and the stepping motor controller (8).

The invention relates to a photovoltaic inverter inductance compensation control method. A transfer function is adjusted correspondingly through change of hardware nonlinear inductance and current to achieve nonlinear characteristic inductance compensation control. The current nonlinear inductance is adopted, inductance cost is reduced, size is compressed, system noise and power consumption are reduced, grid connection stability and reliability of a photovoltaic inverter are improved, and system power generation efficiency is improved. The method solves the problem of difficulty of the nonlinear characteristic inductance in an inverter control strategy, and the technical scheme can be applied to power electronic topological circuits of wind power inverters, uninterruptible power supplies (UPS) and the like.

The invention relates to the field of component simulation modeling for power electronics and power systems, in particular to a modeling method of a broadband circuit model of a silicon steel sheet iron core. According to the method, after reasonable subdivision is conducted on each layer of silicon steel sheets, the iron core is equalized into a trapezoidal circuit on the basis of an equivalent circuit method, the circuit can be connected with an external circuit according to certain rules, and therefore a whole system is analyzed and calculated; according to the penetration depth of electromagnetic waves in the iron core under normal working conditions, each silicon steel sheet in the iron core is divided into three layers to determine the order of the iron core circuit model, the equivalent eddy current resistance Rek and nonlinear inductance Ldk of each layer of the layered silicon steel sheets are calculated, a passive two-port transmission network is defined and used for converting the physical quantity of the external circuit side of the iron core to that of the equivalent network side of a single silicon steel sheet, and finally the multi-iron-core model connected with theexternal circuit is established. According to the modeling method of the broadband circuit model of the silicon steel sheet iron core, the equivalent circuit method is adopted, the non-uniformity of the magnetic field distribution inside the iron core is taken into account, the equivalent model of the iron core is established, and therefore complex electromagnetic field calculation can be converted into simple circuit calculation.

The invention discloses a novel power cable short circuit current limiter, which comprises a metal oxide varistor, an iron core, a winding coil, a fast switch and a fast switch controller, wherein the fast switch and the fast switch controller, the iron core and the winding coil, and the metal oxide varistor are in parallel connection; in the case of failure, the iron core and the winding coil are serially connected to the system to generate nonlinear inductance to limit short circuit current; the fast switch is serially connected to the system circuit and on or off of the fast switch is controlled by the fast switch controller; and the metal oxide varistor provides overvoltage support when the fast switch is on and off. The novel power cable short circuit current limiter has the significant effects that a DC bias circuit does not need to be additionally arranged to enable the iron core to achieve saturation, the system has zero loss in a normal working state, only one iron core is needed for single-phase protection for the system, and three iron cores are only needed for three-phase protection. The novel power cable short circuit current limiter has the advantages of simple structure, convenient operation, reliable working and the like.

A multi-output DC-DC converter that can optimize its cross-regulation performance is proposed, in which a nonlinear inductive element functioning as a leakage inductance of an output coupled inductor is placed on the output channel of at least one secondary circuit coupled to a secondary winding of a transformer. The inductance of the nonlinear inductive element is varied in inverse proportion with the variation of the current flowing through the nonlinear inductive element. When the load on an output end of the DC-DC converter is changed, the output channel having a higher load current is configured to produce a lower leakage inductance and the output channel having a lower load current is configured to produce a higher leakage inductance, and thereby balance the output currents flowing through the output channels of the DC-DC converter.

The invention discloses a novel short circuit current limiter. The novel short circuit current limiter comprises a metal oxide pressure-sensitive resistor, an iron core, a winding coiling, a snap switch and a snap switch controller; the snap switch, the snap switch controller, the iron core, the winding coil and the metal oxide pressure-sensitive resistor are connected in parallel; in case of fault, the iron core and the winding coil are arranged into the system in series to generate nonlinear inductance to limit short circuit current; the snap switch is connected in series into a system line and controlled by the snap switch controller to be on or off; the metal oxide pressure-sensitive resistor provides overvoltage support when turning on and turning off the snap switch. The novel short circuit current limiter has the obvious effects that a DC biasing circuit added for enabling saturation of the iron core is avoided; the zero loss of the system under the normal state is reached; one iron core is needed in the single-phase protection of the system, and three-phase protection needs only three iron cores. The novel short circuit current limiter has the advantages of being simple in structure, convenient to operate, and reliable to work.

The invention provides a nonlinear inductance modeling method for three-phase electrically excited doubly salient motors. The nonlinear inductance modeling method is based on influence laws of armature currents and excitation currents of the three-phase electrically excited doubly salient motors on inductance parameters. The nonlinear inductance modeling method includes acquiring transverse axis translation of two curves by the aid of influence relation curves of the armature currents on the inductance parameters under two excitation current conditions; acquiring the influence relation curvesof the armature currents on the inductance parameters in total excitation current ranges in correspondence to excitation current difference values of the two curves. The nonlinear inductance modelingmethod has the advantages that influence of armature reaction and excitation magnetic field variation are taken into account, and the nonlinear inductance modeling method for the three-phase electrically excited doubly salient motors is accurate, simple and convenient.

The invention relates to a fuzzy single-cycle control method with a nonlinear inductor PFC circuit. Single-cycle control is widely used in PFC circuit design because single-cycle control has the characteristic of given tracking in each switching cycle. The inductance in a single-cycle algorithm is calculated as a fixed value, and the inductance of an inductor changes with the change of current. The single-cycle control effect fails to meet desired requirements, and a new control policy is needed. In view of the nonlinear inductor, the invention proposes the fuzzy single-cycle control algorithm. The problem of system performance deterioration caused by changes in the inductance in original single-cycle control is effectively solved. The digital control structure of the bidirectional switching PFC is simplified. The control effect of the system is improved.

A switchable buck-converter with zero voltage switching capability includes a non-linear inductor having an inductance as a function of a load current to allow for a constant switching frequency operation of the switchable buck-converter.