CN101714450B - Electrical design method of saturable reactor for direct current converter valve - Google Patents

Abstract

The invention provides an electrical design method of a saturable reactor for a direct current converter valve, in particular to an electrical design method of a saturable reactor with a simple winding structure, thereby filling the blank of the filed in our country. The main electrical performance indexes of the saturable reactor are provided, the contents of the electrical design mainly comprise six main parts, namely original selection of an iron core, primary winding design, iron core zoom analysis, iron core air gap design, saturation segment analysis and the like, and a calibration and modification part; the design route is as follows: calculating to determine the structure size of equipment according to core performance parameters, adopting other parameters to calibrate and modify until meeting requirements, and designing the next part; and the design flow is strict and detailed, thereby realizing programming and modularization of design work.

Description

A kind of electrical design method of saturable reactor for direct current converter valve

Technical field

The present invention relates to the electric power system devices field, relate in particular to a kind of electrical design method of saturable reactor for direct current converter valve.

Background technology

Saturable reactor is the critical component of protection thyristor converter valve in the ultra extra-high voltage direct-current transmission equipment.Its topmost function be restriction converter valve thyristor device when opening because the huge di/dt that the stray capacitance discharge causes; The situation limit that externally applies surge voltage is applied to the huge dv/dt on the thyristor device, simultaneously the tasks such as all pressures of auxiliary triode thyristor module and inter-module.

Saturable reactor electrical design target is the geometric parameter of and winding construction, core material parameter and winding unshakable in one's determination through choose reasonable etc., makes the reactor device satisfy the electric property requirement to saturable reactor that proposes based on relevant operating condition in the converter valve system.At present; The overall operation of domestic saturable reactor also rests on the imitated stage, the work in research and development field as yet not system carry out, the foreign scholar delivered the scientific paper of some iron core characteristics researchs; But the electrical design method of system does not also form, and does not see relevant open report.And the core technology of the research and development of saturable reactor and manufacturing is grasped in the large scale electrical power unit supplier hand that can carry out the converter valve equipment supply in the world few in number, and this part technical data holds in close confidence.

Summary of the invention

The objective of the invention is: a kind of saturable reactor for converter valve electrical design method is provided, realizes the standardization of design process, standardization.

The iron core that The present invention be directed in the simplex winding form proposes its electrical design method around the shell-type structure of coil.This inductance coil that comprises non-linear iron core that may be summarized to be simple in structure.Therefore the action of electrical design mainly comprises core design and coil design two large divisions.

A kind of DC converter valve of the present invention is used electrical design method of saturable reactor; May further comprise the steps: iron core primary election, design of Windings, iron core refinement analysis, iron core air gap design and a saturated piecewise analysis step; It is characterized in that the electric property parameter index according to saturable reactor, confirm the basic parameter or the device structure of reactor arrangement: fit, iron core and the coil material separately that comprises geometry form, structure building block, iron core and the coil of confirming reactor is selected and index such as physical dimension; And after obtaining a parameter, whether meet the demands,, then revise initial setting, calculate again and verification, till all parameters all meet the demands, carry out the design of next part then if do not meet the demands with regard to other parameters of verification; The electric property parameter index of said saturable reactor comprises:

(1) reactor maximum voltage time product, promptly magnetic linkage changes maximum Δ Ψ=∫ Udt;

(2) reactor allows the maximum current I that flows through _Max

(3) reactor bears voltage max U _Max

(4) reactor air core inductor L _Air

(5) reactor D.C. resistance R _Cu

(6) the main sense of reactor is with change in current curve Lm (i);

(7) reactor iron loss resistance is with change in current curve Re (i);

(8) stray capacitance Cf between the reactor end.

Specifically may further comprise the steps:

At first obtain the electric property parameter index of saturable reactor, as the initial conditions of whole design process;

The first step according to the weber number, is confirmed iron core equivalence linkage area, in conjunction with the coil turn of setting, confirms the required core area of each reactor;

Second step, a design of Windings, needs are confirmed external diameter, equivalent magnetic circuit length and winding single turn area of turn-to-turn distance, circle wheelbase and the circle span and the hollow tube of winding;

Then according to the area of a core area and a winding, and combine winding and assembly relation unshakable in one's determination, whether inspection need adjust area unshakable in one's determination, if do not need adjustment, then continues next step, and the first step is got back in adjustment so if desired, adjusts once more;

In the 3rd step, coiling iron core thickness is selected in refinement unshakable in one's determination, and physical dimension;

In the 4th step, the selection of air gap unshakable in one's determination is in conjunction with the core material of tentatively choosing;

The 5th step, saturated piecewise analysis unshakable in one's determination, on the BH curve basis of selected core material, calculating inductance and eddy current resistance change curve;

The inductance and the eddy current resistance change curve that calculate according to selected material then; Check in conjunction with the inductance of saturable reactor and the requirement of eddy current resistance change curve,, then need readjust the selection of core material if misfit; Got back to for the 3rd step and recomputate, readjust; If coincide, then electrical design work is accomplished.

Method of the present invention also comprises verification correction step:

After second step was finished, according to the area of a core area and a winding, whether inspection need adjust area unshakable in one's determination, if do not need adjustment, then continues next step, and the first step is got back in adjustment so if desired, adjusts once more;

After the 5th step was finished; The inductance and the eddy current resistance change curve that calculate according to selected material; Check in conjunction with the inductance of saturable reactor and the requirement of eddy current resistance change curve,, then need readjust the selection of core material if misfit; Got back to for the 3rd step and recomputate, readjust; If coincide, then electrical design work is accomplished.

Specifically may further comprise the steps:

(1) on the basis that the converter valve system electrical is analyzed, obtains the electric property parameter index that saturable reactor need satisfy, as the input parameter of whole implementation;

(2) according to the weber number of required saturable reactor, confirm iron core equivalence linkage area, in conjunction with the coil turn of setting, confirm the core area that each reactor is required;

Wherein:

is the weber number, in the design input, provides; N is a coil turn, considers structural lightly, generally selects 3～4 circles; B is a magnetic flux density unshakable in one's determination, is determined by the core material performance;

The design of (3) winding space layouts, the turn-to-turn of confirming winding height H grp and the width W grp behind d4, circle wheelbase d5, circle span d6, the D outer diameter ww of coil, the casting insulated material of winding;

After coil turn is selected, according to the maximum that saturable reactor bears voltage, can confirm the magnitude of voltage that single-turn circular coil bears, the dielectric strength of epoxy resin is by its material properties decision; The two is divided by, and considers certain nargin coefficient again, can confirm the turn-to-turn distance, the circle wheelbase; The circle span, wherein, saturable reactor bears voltage max; Epoxy numerical value dielectric strength, the nargin coefficient of each physical dimension is the design initial conditions;

The current density that maximum current that allows to flow through according to saturable reactor and coil method allow; Can confirm the equivalent cross-sectional area of a winding; And then the equivalent through-flow diameter Dwire of definite winding; A kind of structural shape of using always in the saturable reactor is to adopt the metal tubes of hollow as coil, and heat dissipation pipe's diameter Dwater in can confirming according to the heat radiation requirement accordings to the D outer diameter ww that following formula can be confirmed a winding:

$D_{\mathrm{ww}}=\sqrt{D_{\mathrm{wire}}^2+D_{\mathrm{water}}^2}---\left(2\right)$

Wherein, saturable reactor allows the maximum current that flows through, the current density of material, and interior heat dissipation pipe's diameter is initial conditions, on this basis, can further calculate height and thickness behind the casting insulated material of winding:

H _grp＝ND _ww+(N-1)d ₄+2d ₅ (3)

W _grp＝D _ww+2d ₆ (4)

Single turn area Sw, length L w and the width Rw of a winding are confirmed in the design of (4) winding single turn parameters;

Can calculate the single turn area Sw of a winding according to following formula:

$S_w=\frac{L_{\mathrm{air}}\·L_{\mathrm{eq}}}{{\mathrm{\μ}}_0\·N^2}---\left(5\right)$

Wherein, Lair is an air core inductor, and μ 0 is a magnetic permeability, is initial conditions, and Leq is the air core inductor equivalent magnetic circuit, and computing formula is following:

L _eq＝2(H _grp+W _grp) (6)

Can calculate the length and the width of single-turn winding according to following two formulas:

$\mathrm{\π}{R}_w^2-\frac{\mathrm{\π}{R}_{\mathrm{cu}}{D}_{\mathrm{wire}}^2}{4{\mathrm{\ρ}}_{\mathrm{cu}}N}{R}_w+S_w=0---\left(7\right)$

$L_w=\frac{\mathrm{\π}{R}_{\mathrm{cu}}{D}_{\mathrm{wire}}^2}{8{\mathrm{\ρ}}_{\mathrm{cu}}N}-\mathrm{\π}{R}_w---\left(8\right)$

In the formula, Rcu is a winding direct current substitutional resistance, and pcu is the resistivity of winding material, is input parameter;

If Sw＞S, then design meets the demands, and proceeds next step, otherwise carries out design of Windings again one time;

(5) theoretic throat Wfe unshakable in one's determination is confirmed in refinement unshakable in one's determination, actual (real) thickness C unshakable in one's determination, and width F, height G, single iron core cake length D, quantity Nfe unshakable in one's determination:

W _fe＝S/L _fe (9)

Wherein Lfe is a total length unshakable in one's determination, and its value requires less than Lw; According to F >=Wgrp, three constraintss of G >=Hgrp and C >=Wfe are selected the cake unshakable in one's determination of moulding, according to cake length D unshakable in one's determination, in conjunction with thickness d 7 between cake unshakable in one's determination, can confirm quantity Nfe unshakable in one's determination:

$N_{\mathrm{fe}}=\frac{L_{\mathrm{fe}}+d_7}{D+d_7}---\left(10\right)$

(6) air gap delta unshakable in one's determination is confirmed in the calculating of air gap unshakable in one's determination.：

At first calculate the relative permeability of saturable reactor:

${\mathrm{\μ}}_{\mathrm{er}}=\frac{L_m}{L_{\mathrm{air}}}\frac{S_w}{S}---\left(11\right)$

Equivalent inductance unshakable in one's determination when wherein Lm is a unsaturation unshakable in one's determination, secondly, calculate inner magnetic flux density unshakable in one's determination:

$B=\frac{{\mathrm{\μ}}_0{\mathrm{\μ}}_{\mathrm{er}}{\mathrm{NI}}_m{L}_m}{L_{\mathrm{eq}}}---\left(12\right)$

Wherein Im is a keen current unshakable in one's determination, in selected BH curve unshakable in one's determination, searches the working point of this moment and the magnetic field intensity Hfe of correspondence thereof, calculates the relativepermeability of this moment:

${\mathrm{\μ}}_r=\frac{B}{{\mathrm{\μ}}_{0}H}---\left(13\right)$

Can calculate air gap unshakable in one's determination according to following formula:

$\mathrm{\δ}=\frac{({\mathrm{\μ}}_r-{\mathrm{\μ}}_{\mathrm{er}})L_{\mathrm{eq}}}{({\mathrm{\μ}}_r-1){\mathrm{\μ}}_{\mathrm{er}}}---\left(14\right)$

(7) confirm the relation curve Lm (i) that main inductance changes with winding current i:

$L_m\left(i\right)=\frac{N^{2}k{A}_C{L}_{\mathrm{eq}}}{I_m}\frac{\mathrm{di}}{{\mathrm{dH}}_a}---\left(15\right)$

Wherein, AC and k represent cross-sectional area unshakable in one's determination and lamination coefficient respectively, by selected characteristic unshakable in one's determination decision; Ha is an average magnetic field intensity, is calculated as follows:

$H_a=\frac{\mathrm{Ni}}{L_{\mathrm{eq}}}---\left(16\right)$

(8) confirm the relation curve Re (i) that iron loss resistance changes with electric current:

$\mathrm{Re}\left(i\right)=\frac{4N^2{B}_s{\mathrm{\ρ}}_{\mathrm{fe}}k{A}_C}{p^2{L}_{\mathrm{eq}}{B}_{\mathrm{av}}\left(t\right)}---\left(17\right)$

Wherein, pfe is a resistivity unshakable in one's determination, and p is a coiling thickness unshakable in one's determination, and Bs is a saturation flux density unshakable in one's determination, is intrinsic property unshakable in one's determination; Bav (t) is different average flux density unshakable in one's determination constantly, according to circuital law, can be confirmed by correspondence winding current constantly, so just can set up the corresponding relation of Re and i;

(9) according to the selected core material and the material of air gap unshakable in one's determination; Calculate the inductance and the eddy current resistance change curve of saturable reactor; Requirement in conjunction with the inductance and the eddy current resistance change curve of saturable reactor? Check,, then need readjust the selection of core material if misfit; Get back to step (5), readjust; If coincide, then electrical design work is accomplished;

(10) the confirming of stray capacitance Cf between the saturable reactor end:

Stray capacitance can be estimated according to following formula by the structures shape of reactor:

$C_f=\mathrm{\ϵ}\frac{S_c}{d_c}---\left(18\right)$

Wherein, ε is a dielectric constant of air; Sc is the busbar area; Dc is the busbar spacing, if the estimation result requires at the same order of magnitude with the design input, it is qualified then to design; If gap is bigger, then returns step (4) and design again;

(11), accomplish the electrical design of saturable reactor with above-mentioned each geometric parameter, material parameter, the structural parameters output of unshakable in one's determination and winding.

Wherein, said stray capacitance adopts the Numerical Calculation of Electromagnetic Fields method to carry out modeling and calculating by the structures shape of reactor; At first, saturable reactor is carried out whole modeling, second step was carried out the numerical value mesh generation to model; The 3rd step applied the border incentive condition; The 4th step number value is found the solution, and is last, obtains stray capacitance through reprocessing.

Wherein, this method for designing can be used for the electrical design of simplex winding structure saturable reactor, also can be used for a Winding Design job to the saturable reactor double-winding structure, and the electrical design of double-winding structure is played booster action.

The invention has the beneficial effects as follows:

1, design cycle is rigorous full and accurate, has realized the sequencing and the modularization of design work;

2, the mentality of designing of the science of " confirm the device structure size according to the core capabilities calculation of parameter, other parameters are carried out the verification correction " has been adopted in design work.

Description of drawings

Below in conjunction with accompanying drawing the present invention is further specified.

Fig. 1 is the schematic flow sheet of electrical design method of saturable reactor for direct current converter valve of the present invention.

Fig. 2 is certain BH curve unshakable in one's determination.

Embodiment

The implementation of method for designing proposed by the invention is following, and is as shown in Figure 1.

At first obtain the requirement of the electric parameter of saturable reactor, as the input of whole implementation.

The first step according to the weber number, is confirmed iron core equivalence linkage area, in conjunction with the coil turn of setting, confirms the required core area of each reactor.

Second step, a design of Windings.External diameter, equivalent magnetic circuit length and a winding single turn area of needing turn-to-turn distance, circle wheelbase and the circle span and the hollow tube of definite winding.

Then according to the area of a core area and a winding, and combine winding and assembly relation unshakable in one's determination, whether inspection need adjust area unshakable in one's determination, if do not need adjustment, then continues next step.The first step is got back in adjustment so if desired, adjusts once more.

The 3rd step, refinement unshakable in one's determination.Select coiling iron core thickness, and physical dimension.

In the 4th step, the selection of air gap unshakable in one's determination is in conjunction with the core material of tentatively choosing.

The 5th step, saturated piecewise analysis unshakable in one's determination.On the BH curve basis of selected core material, calculating inductance and eddy current resistance change curve, as shown in Figure 2.

The inductance and the eddy current resistance change curve that calculate according to selected material then; Check in conjunction with the inductance of saturable reactor and the requirement of eddy current resistance change curve; If misfit, then need readjust the selection of core material and get back to for the 3rd step, readjust; If coincide, then electrical design work is accomplished.

Can electrical design work be accomplished in each geometric parameter, material parameter, the structural parameters output of unshakable in one's determination and winding.

Fig. 2 is certain BH curve unshakable in one's determination, and the BH curve is magnetic flux density B unshakable in one's determination and magnetic field intensity H variation relation curve, although different BH curve unshakable in one's determination is had nothing in common with each other; But the Changing Pattern of curve is close; That is, initial period is a linear change, along with the increase of magnetic field intensity; Progress into saturated section, B and H are non-linear relation.

Invention has been described according to specific exemplary embodiment here.It will be conspicuous under not departing from the scope of the present invention, carrying out suitable replacement to one skilled in the art or revise.Exemplary embodiment only is illustrative, rather than to the restriction of scope of the present invention, scope of the present invention is by appended claim definition.

Claims (5)

1. a DC converter valve is used electrical design method of saturable reactor; May further comprise the steps: iron core primary election, design of Windings, iron core refinement analysis, iron core air gap design and a saturated piecewise analysis step; It is characterized in that the electric property parameter index according to saturable reactor, confirm the basic parameter or the device structure of reactor arrangement: fit, iron core and the coil material separately that comprises geometry form, structure building block, iron core and the coil of confirming reactor is selected and the physical dimension index; And after obtaining a parameter, whether meet the demands,, then revise initial setting, calculate again and verification, till all parameters all meet the demands, carry out the design of next part then if do not meet the demands with regard to other parameters of verification; The electric property parameter index of said saturable reactor comprises:

(1) reactor maximum voltage time product, promptly magnetic linkage changes maximum Δ Ψ=∫ Udt;

(2) reactor allows the maximum current I that flows through _Max

(3) reactor bears voltage max U _Max

(4) reactor air core inductor L _Air

(5) reactor D.C. resistance R _Cu

(6) the main sense of reactor is with change in current curve L _m(i);

(7) reactor iron loss resistance is with change in current curve Re (i); With

(8) stray capacitance C between the reactor end _f

2. method for designing as claimed in claim 1 is characterized in that may further comprise the steps:

At first obtain the electric property parameter index of saturable reactor, as the initial conditions of whole design process;

The first step according to the weber number, is confirmed iron core equivalence linkage area, in conjunction with the coil turn of setting, confirms the required core area of each reactor;

Second step, a design of Windings, needs are confirmed external diameter, equivalent magnetic circuit length and winding single turn area of turn-to-turn distance, circle wheelbase and the circle span and the hollow tube of winding;

Then according to the area of a core area and a winding, and combine winding and assembly relation unshakable in one's determination, whether inspection need adjust area unshakable in one's determination, if do not need adjustment, then continues next step, and the first step is got back in adjustment so if desired, adjusts once more;

In the 3rd step, coiling iron core thickness is selected in refinement unshakable in one's determination, and physical dimension;

In the 4th step, the selection of air gap unshakable in one's determination is in conjunction with the core material of tentatively choosing;

The 5th step, saturated piecewise analysis unshakable in one's determination, on the BH curve basis of selected core material, calculating inductance and eddy current resistance change curve;

The inductance and the eddy current resistance change curve that calculate according to selected material then; Check in conjunction with the inductance of saturable reactor and the requirement of eddy current resistance change curve,, then need readjust the selection of core material if misfit; Got back to for the 3rd step and recomputate, readjust; If coincide, then electrical design work is accomplished.

3. method for designing as claimed in claim 2 specifically may further comprise the steps:

(1) on the basis that the converter valve system electrical is analyzed, obtains the electric property parameter index that saturable reactor need satisfy, as the input parameter of whole implementation;

(2) according to the weber number of required saturable reactor, confirm iron core equivalence linkage area, in conjunction with the coil turn of setting, confirm the core area that each reactor is required;

Wherein:

is the weber number, in the design input, provides; N is a coil turn, considers structural lightly, selects 3～4 circles; B is a magnetic flux density unshakable in one's determination, is determined by the core material performance;

The design of (3) winding space layouts, the turn-to-turn of confirming winding is apart from d ₄, circle wheelbase d ₅, circle span d ₆, coil D outer diameter _Ww, the height H behind the casting insulated material of winding _GrpAnd width W _Grp

After coil turn is selected, according to the maximum that saturable reactor bears voltage, can confirm the magnitude of voltage that single-turn circular coil bears, the dielectric strength of epoxy resin is by its material properties decision; The two is divided by, and considers certain nargin coefficient again, can confirm the turn-to-turn distance, the circle wheelbase; The circle span, wherein, saturable reactor bears voltage max; Epoxy resins insulation intensity, the nargin coefficient of each physical dimension is the design initial conditions;

The current density that maximum current that allows to flow through according to saturable reactor and coil method allow can be confirmed the equivalent cross-sectional area of a winding and then the equivalent through-flow diameter D of definite winding _Wire, a kind of structural shape commonly used is to adopt the metal tubes of hollow as coil in the saturable reactor, heat dissipation pipe's diameter D in requiring to confirm according to heat radiation _Water, according to the D outer diameter that following formula is confirmed a winding _Ww:

$D_{\mathrm{ww}}=\sqrt{D_{\mathrm{wire}}^2+D_{\mathrm{water}}^2}---\left(2\right)$

Wherein, saturable reactor allows the maximum current that flows through, the current density of material, and interior heat dissipation pipe's diameter is initial conditions, on this basis, can further calculate height and thickness behind the casting insulated material of winding:

H _grp＝ND _ww+(N-1)d ₄+2d ₅ (3)

W _grp＝D _ww+2d ₆ (4)

The single turn area S of a winding is confirmed in the design of (4) winding single turn parameters _w, length L _wWith width R _w

Can calculate the single turn area S of a winding according to following formula _w:

$S_w=\frac{L_{\mathrm{air}}\·L_{\mathrm{eq}}}{{\mathrm{\μ}}_0\·N^2}---\left(5\right)$

Wherein, L _AirBe air core inductor, μ ₀Be magnetic permeability, be initial conditions, L _EqBe the air core inductor equivalent magnetic circuit, computing formula is following:

L _eq＝2(H _grp+W _grp) (6)

Can calculate the length and the width of single-turn winding according to following two formulas:

$\mathrm{\π}{R}_w^2-\frac{\mathrm{\π}{R}_{\mathrm{cu}}{D}_{\mathrm{wire}}^2}{4{\mathrm{\ρ}}_{\mathrm{cu}}N}{R}_w+S_w=0---\left(7\right)$

$L_w=\frac{\mathrm{\π}{R}_{\mathrm{cu}}{D}_{\mathrm{wire}}^2}{8{\mathrm{\ρ}}_{\mathrm{cu}}N}-\mathrm{\π}{R}_w---\left(8\right)$

In the formula, R _CuBe winding direct current substitutional resistance, ρ _CuResistivity for winding material is input parameter;

If S _w＞S, then design meets the demands, and proceeds next step, otherwise carries out design of Windings again one time;

(5) theoretic throat W unshakable in one's determination is confirmed in refinement unshakable in one's determination _Fe, actual (real) thickness C unshakable in one's determination, width F, height G, single iron core cake length D, quantity N unshakable in one's determination _Fe:

W _fe＝S/L _fe (9)

L wherein _FeBe total length unshakable in one's determination, its value requires less than L _wAccording to F>=W _Grp, G>=H _GrpAnd C>=W _FeThree constraintss are selected the cake unshakable in one's determination of moulding, according to cake length D unshakable in one's determination, in conjunction with thickness d between cake unshakable in one's determination ₇, can confirm quantity N unshakable in one's determination _Fe:

$N_{\mathrm{fe}}=\frac{L_{\mathrm{fe}}+d_7}{D+d_7}---\left(10\right)$

(6) calculating of air gap unshakable in one's determination, confirm air gap delta unshakable in one's determination:

At first calculate the relative permeability of saturable reactor:

${\mathrm{\μ}}_{\mathrm{er}}=\frac{L_m}{L_{\mathrm{air}}}\frac{S_w}{S}---\left(11\right)$

L wherein _mEquivalent inductance unshakable in one's determination during for unsaturation unshakable in one's determination, secondly, calculate magnetic flux density unshakable in one's determination:

$B=\frac{{\mathrm{\μ}}_0{\mathrm{\μ}}_{\mathrm{er}}{\mathrm{NI}}_m{L}_m}{L_{\mathrm{eq}}}---\left(12\right)$

I wherein _mBe keen current unshakable in one's determination, in selected BH curve unshakable in one's determination, search the working point of this moment and the magnetic field intensity Hfe of correspondence thereof, calculate the relative permeability μ of this moment _r:

${\mathrm{\μ}}_r=\frac{B}{{\mathrm{\μ}}_{0}H}---\left(13\right)$

Can calculate air gap unshakable in one's determination according to following formula:

$\mathrm{\δ}=\frac{({\mathrm{\μ}}_r-{\mathrm{\μ}}_{\mathrm{er}})L_{\mathrm{eq}}}{({\mathrm{\μ}}_r-1){\mathrm{\μ}}_{\mathrm{er}}}---\left(14\right)$

(7) confirm the relation curve L that main inductance changes with winding current i _m(i):

$L_m\left(i\right)=\frac{N^{2}k{A}_C{L}_{\mathrm{eq}}}{I_m}\frac{\mathrm{di}}{{\mathrm{dH}}_a}---\left(15\right)$

Wherein, A _CRepresent cross-sectional area unshakable in one's determination and lamination coefficient respectively with k, by selected characteristic unshakable in one's determination decision; H _aBe average magnetic field intensity, be calculated as follows:

$H_a=\frac{\mathrm{Ni}}{L_{\mathrm{eq}}}---\left(16\right)$

(8) confirm the relation curve Re (i) that iron loss resistance changes with electric current:

$\mathrm{Re}\left(i\right)=\frac{4N^2{B}_s{\mathrm{\ρ}}_{\mathrm{fe}}k{A}_C}{p^2{L}_{\mathrm{eq}}{B}_{\mathrm{av}}\left(t\right)}---\left(17\right)$

Wherein, ρ _FeBe resistivity unshakable in one's determination, p is a coiling thickness unshakable in one's determination, B _sBe saturation flux density unshakable in one's determination, be intrinsic property unshakable in one's determination; B _Av(t) be different average flux density unshakable in one's determination constantly,, can confirm, so just can set up the corresponding relation of Re and i by correspondence winding current constantly according to circuital law;

(9) according to the selected core material and the material of air gap unshakable in one's determination; Calculate the inductance and the eddy current resistance change curve of saturable reactor; Check in conjunction with the inductance of saturable reactor and the requirement of eddy current resistance change curve,, then need readjust the selection of core material if misfit; Get back to step (5), readjust; If coincide, then electrical design work is accomplished;

(10) stray capacitance C between the saturable reactor end _fConfirm:

Stray capacitance can be estimated according to following formula by the structures shape of reactor:

$C_f=\mathrm{\ϵ}\frac{S_c}{d_c}---\left(18\right)$

Wherein, ε is a dielectric constant of air; S _cBe the busbar area; d _cBe the busbar spacing, if the estimation result requires at the same order of magnitude with the design input, it is qualified then to design; If gap is bigger, then returns step (4) and design again;

(11), accomplish the electrical design of saturable reactor with each geometric parameter, material parameter, the structural parameters output of unshakable in one's determination and winding.

4. method for designing as claimed in claim 3 is characterized in that the structures shape of said stray capacitance by reactor, adopts the Numerical Calculation of Electromagnetic Fields method to carry out modeling and calculating; At first, saturable reactor is carried out whole modeling, second step was carried out the numerical value mesh generation to model; The 3rd step applied the border incentive condition; The 4th step number value is found the solution, and is last, obtains stray capacitance through reprocessing.

5. method for designing as claimed in claim 1; It is characterized in that this method for designing is used for the electrical design of simplex winding structure saturable reactor; Or be used for a Winding Design job to the saturable reactor double-winding structure, the electrical design of double-winding structure is played booster action.

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