CN103337998B - A kind of vertical force control method of flux-reversal permanent-magnetism linear motor - Google Patents

Abstract

The invention discloses a kind of vertical force control method of flux-reversal permanent-magnetism linear motor.The method comprises vertical force optimal algorithm and controls switch, described vertical force optimal algorithm is: obtain optimum d, q shaft current by setting up auxiliary function, minimum copper loss and vertical force is obtained when keeping thrust constant when steady operation, thus lifting motor operating efficiency and performance; Described control switch is: movement segment adopts d shaft current to be the control model of zero, and steady-state process adopts vertical force optimal control pattern, and the method response is fast, easy.

Description

A kind of vertical force control method of flux-reversal permanent-magnetism linear motor

Technical field

The present invention relates to a kind of vertical force control method, particularly a kind of vertical force control method of flux-reversal permanent-magnetism linear motor.

Background technology

Along with the development in China city, traffic problems have become a bottleneck of urban development.Linear Motor Rail Transit System system is because of advantages such as climbing capacity are strong, circuit applicability is strong, project cost is low and noise is low, and the application in urban track traffic also more and more comes into one's own.Linear electric motors are divided into induction type and magneto.China, Guangzhou Underground No. four lines have employed Linear-motor Vehicle at home first, and what its traction electric machine adopted is induction linear electric motor, but this motor has the shortcomings such as reactive power loss is large, power factor is low; Permanent magnetic linear synchronous motor is higher than induction linear electric motor energy index, efficiency is high, power factor is high, only need from electrical network, draw active power externally to do work, but shortcoming be no matter by winding or permanent magnet along track laying, all greatly will increase project cost, safeguard comparatively difficulty.

A kind of novel electric machine structure that flux-reversal permanent-magnetism linear motor is complied with motor development trend just and proposed, it is organically combined induction linear electric motor and permanent-magnetism linear motor, the novel permanent magnetic linear electric motors of the two-fold advantage of both.There are some researches show, motor vertical force is the key factor affecting efficiency, and numerical value is generally the 2-8 of horizontal thrust doubly, greatly increases resistance when motor runs, and reduces operating efficiency.The operating efficiency how improving flux-reversal permanent-magnetism linear motor further becomes key issue urgently to be resolved hurrily in research.

Summary of the invention

For problems of the prior art, the object of the present invention is to provide a kind of when steady operation keep thrust constant obtain minimum copper loss and vertical force, thus lifting motor operating efficiency and performance, response is fast, the vertical force control method of easy flux-reversal permanent-magnetism linear motor.

In order to achieve the above object, the present invention by the following technical solutions: a kind of vertical force control method of flux-reversal permanent-magnetism linear motor, step comprises:

1) adopt electromagnetic force in linear electric motors Z-direction and vertical force are obtained to the method for maxwell's electromagnetic force tensor surface integration, then push away by finite element simulation or pressure sensor actual measurement the vertical force drawing flux-reversal permanent-magnetism linear motor Ψ _d, Ψ _qbe respectively motor straight, quadrature axis magnetic linkage, Λ is the magnetic leakage factor of motor, and g is the air gap of motor, performs step 2 afterwards);

2) the frictional force F caused by vertical force is determined _f=BF _v, B is rolling resistance of wheel coefficient, performs step 3 afterwards);

3) according to set additional electromagnetic thrust with additional copper loss and the frictional force F that vertical force causes _fset up auxiliary function formula $h(i_d,i_q,\mathrm{\λ})=P_{\mathrm{cu}}+F_f+\mathrm{\λ}[F_{\mathrm{em}}-\frac{3\mathrm{\π}}{\mathrm{\τ}}({\mathrm{\ψ}}_d{i}_q-{\mathrm{\ψ}}_q{i}_d)],$ τ is motor secondary pole span, R _sfor the resistance of armature winding, λ is Lagrange multiplier, d shaft current i _d, q shaft current i _q, perform step 4 afterwards);

4) by auxiliary function respectively to d shaft current i _d, q shaft current i _qask partial derivative with Lagrange multiplier λ and make it be zero, drawing optimum d shaft current $i_d=\frac{-b}{4a}-\frac{1}{2}\sqrt{\frac{b^2}{4a^2}-\frac{2c}{3a}+\mathrm{\σ}}-\frac{1}{2}\sqrt{\frac{b^2}{2a^2}-\frac{4c}{3a}-\mathrm{\σ}-\frac{\frac{-b^3}{a^3}+\frac{4\mathrm{bc}}{a^2}-\frac{8d}{a}}{4\sqrt{\frac{b^2}{4a^2}-\frac{2c}{3a}}+\mathrm{\σ}}},$ Optimum q shaft current $i_q=\frac{F_{\mathrm{em}}^2\mathrm{\τ}}{3\mathrm{\π}({\mathrm{\ψ}}_d-l_q{i}_d)}$ Its $\mathrm{\σ}=\frac{\sqrt[3]{2}{\mathrm{\σ}}_1}{3a^3\sqrt{{\mathrm{\σ}}_2+\sqrt{-4{\mathrm{\σ}}_1^3+{\mathrm{\σ}}_2^2}}}+\frac{\sqrt[3]{{\mathrm{\σ}}_2+\sqrt{-4{\mathrm{\σ}}_1^3+{\mathrm{\σ}}_2^2}}}{3\sqrt[3]{2a}},$ σ ₁＝c ²-3bd+12ae，σ ₂＝2c ³-9bcd+27ad ²+27eb ²-72ace， $a=\frac{27{\mathrm{\π}}^2}{{\mathrm{\τ}}^3}{(l_d-l_q)}^3(3R_s+\frac{3B{l}_d}{2\mathrm{\Λg}})b=\frac{81{\mathrm{\π}}^3}{{\mathrm{\τ}}^3}{\mathrm{\ψ}}_m{(l_q-l_d)}^2(3R_s+\frac{7B{l}_d-l_{q}B}{4\mathrm{\Λg}})$ $c=\frac{243{\mathrm{\π}}^3}{{\mathrm{\τ}}^3}{\mathrm{\ψ}}_m^2(l_q-l_d)(\frac{B{l}_q-3B{l}_d}{4\mathrm{\Λg}}-R_s),d=\frac{81{\mathrm{\π}}^3}{{\mathrm{\τ}}^3}{\mathrm{\ψ}}_m^2(R_s+\frac{5B{l}_d-3B{l}_q}{4\mathrm{\Λg}}),$ $e=\frac{27{\mathrm{\π}}^2{\mathrm{\ψ}}_m^{3}B}{4\mathrm{\Λg}{\mathrm{\τ}}^2}+\frac{9\mathrm{\π}}{\mathrm{\τ}}{F}_{\mathrm{em}}^2(l_q-l_d)(R_s+\frac{B{l}_q}{2\mathrm{\Λg}}),$ L _dfor d axle inductance, l _qfor q axle inductance, perform step 5 afterwards);

5) switch i is controlled according to additional _d=a (e) i ₁+ { 1-a (e) } i ₂carry out the switching of control model, a (e) is switching factor, if v _s-v=e velocity measuring, its v _sfor given speed, v is motor feedback speed, and p switches point value for presetting.As | e|>p, for starting, stop and speed governing movement segment time, then a (e)=1, i ₁=i _d=0, namely use i _dthe Hysteresis Current vector control system of=0 controls motor, does not control the vertical force of motor; Otherwise, during for stable state fortune condition, a (e)=0, i ₂=i _d, namely control motor by optimum d shaft current, perform step 6 afterwards);

6) described optimum d, q shaft current is injected to Hysteresis Current vector control system, by vertical force controller at the constant lower vertical force to flux-reversal permanent-magnetism linear motor of maintenance thrust $F_v=\frac{3}{4\mathrm{\Λg}}[{\mathrm{\ψ}}_d{i}_d+{\mathrm{\ψ}}_q{i}_q]$ Change, this method terminates.

Adopt technique scheme, the present invention has following beneficial effect:

1. the present invention is on widely used Hysteresis Current vector control drive system basis, proposes a kind of vertical force method for optimally controlling and is applied in flux-reversal permanent-magnetism linear motor, control reliably simple and direct.

2. the present invention is from control strategy, without the need to transforming motor body, only need revise relevant control strategy, can reduce vertical force, reach the optimal control under steady state condition.

3., when motor dynamics step operation, adopt d shaft current to be the control method of zero, simple and reliable, the advantages such as thrust is large.

4. when motor steady-state process operates, adopt optimum d, q shaft current to be controlled, reach under maintenance thrust is constant, obtain minimum copper loss and vertical force, thus the object of lifting motor operating efficiency.

Accompanying drawing explanation

Fig. 1 is the vertical force control method flow chart of a kind of flux-reversal permanent-magnetism linear motor of the present invention.

Fig. 2 is three-phase flux-reversal permanent-magnetism linear motor structural representation.

Fig. 3 is the vertical force controlling party block diagram of flux-reversal permanent-magnetism linear motor.

Fig. 4 is the speed schematic diagram that flux-reversal permanent-magnetism linear motor runs.

Fig. 5 is d, q shaft current schematic diagram that flux-reversal permanent-magnetism linear motor runs.

Three-phase current schematic diagram when Fig. 6 is the operation of flux-reversal permanent-magnetism linear motor.

Vertical force schematic diagram when Fig. 7 is the operation of flux-reversal permanent-magnetism linear motor.

Thrust schematic diagram when Fig. 8 is the operation of flux-reversal permanent-magnetism linear motor.

Embodiment

According to specification drawings and specific embodiments, the present invention is further explained below.

As shown in Figure 1, a kind of vertical force control method of flux-reversal permanent-magnetism linear motor, step comprises:

1) adopt electromagnetic force in linear electric motors Z-direction and vertical force are obtained to the method for maxwell's electromagnetic force tensor surface integration $F_{\mathrm{zi}}=\frac{L_i{\mathrm{\μ}}_0}{4}\underset{0}{\overset{D}{\∫}}\mathrm{Re}[H_z{H}_z^{*}-H_x{H}_x^{*}]\mathrm{dx}=\frac{L_{i}D{\mathrm{\μ}}_0}{4}\frac{1-{\left(R_{m}S\right)}^2}{{\left(\sinh \mathrm{\βg}\right)}^2+{\left(R_m\mathrm{Sg}\cosh \mathrm{\βg}\right)}^2}{K}_s^2$ μ ₀for permeability of vacuum, R _mfor Reynolds number, g is the air gap of motor, K _sprimary surface equivalent current ripple density peaks, τ is motor secondary pole span, then push away by finite element simulation or pressure sensor actual measurement the vertical force drawing flux-reversal permanent-magnetism linear motor Ψ _d, Ψ _qbe respectively motor straight, quadrature axis magnetic linkage, Λ is the magnetic leakage factor of motor, performs step 2 afterwards);

2) the frictional force F caused by vertical force is determined _f=BF _v, B is rolling resistance of wheel coefficient, performs step 3 afterwards);

3) according to set additional electromagnetic thrust with additional copper loss and the frictional force F that vertical force causes _fset up auxiliary function formula $h(i_d,i_q,\mathrm{\λ})=P_{\mathrm{cu}}+F_f+\mathrm{\λ}[F_{\mathrm{em}}-\frac{3\mathrm{\π}}{\mathrm{\τ}}({\mathrm{\ψ}}_d{i}_q-{\mathrm{\ψ}}_q{i}_d)],$ τ is motor secondary pole span, R _sfor the resistance of armature winding, λ is Lagrange multiplier, d shaft current i _d, q shaft current i _q, perform step 4 afterwards);

4) by auxiliary function respectively to d shaft current i _d, q shaft current i _qask partial derivative with Lagrange multiplier λ and make it be zero, $\left\{\begin{array}{c}\frac{\∂h}{\∂i_d}=(3R_s+\frac{3B}{2\mathrm{\Λg}}{L}_d)i_d+\frac{3\mathrm{\π\λ}}{\mathrm{\τ}}(L_q-L_d)i_q+\frac{3B}{4\mathrm{\Λg}}{\mathrm{\ψ}}_m=0\\ \frac{\∂h}{\∂i_q}=(3R_s+\frac{3B}{2\mathrm{\Λg}}{L}_q)i_q+\frac{3\mathrm{\π\λ}}{\mathrm{\τ}}(L_q-L_d)i_d-\frac{3\mathrm{\π\λ}}{\mathrm{\τ}}{\mathrm{\ψ}}_m=0\\ \frac{\∂h}{\∂\mathrm{\λ}}=F_{\mathrm{em}}-\frac{3\mathrm{\π}}{\mathrm{\τ}}{\mathrm{\ψ}}_d{i}_q+\frac{3\mathrm{\π}}{\mathrm{\τ}}{L}_q{i}_d{i}_q=0\end{array}\right.,$ Draw optimum d shaft current $i_d=\frac{-b}{4a}-\frac{1}{2}\sqrt{\frac{b^2}{4a^2}-\frac{2c}{3a}+\mathrm{\σ}}-\frac{1}{2}\sqrt{\frac{b^2}{2a^2}-\frac{4c}{3a}-\mathrm{\σ}-\frac{\frac{-b^3}{a^3}+\frac{4\mathrm{bc}}{a^2}-\frac{8d}{a}}{4\sqrt{\frac{b^2}{4a^2}-\frac{2c}{3a}}+\mathrm{\σ}}},$ Optimum q shaft current $i_q=\frac{F_{\mathrm{em}}^2\mathrm{\τ}}{3\mathrm{\π}({\mathrm{\ψ}}_d-l_q{i}_d)}$ Its $\mathrm{\σ}=\frac{\sqrt[3]{2}{\mathrm{\σ}}_1}{3a^3\sqrt{{\mathrm{\σ}}_2+\sqrt{-4{\mathrm{\σ}}_1^3+{\mathrm{\σ}}_2^2}}}+\frac{\sqrt[3]{{\mathrm{\σ}}_2+\sqrt{-4{\mathrm{\σ}}_1^3+{\mathrm{\σ}}_2^2}}}{3\sqrt[3]{2a}},$ σ ₁＝c ²-3bd+12ae，σ ₂＝2c ³-9bcd+27ad ²+27eb ²-72ace， $a=\frac{27{\mathrm{\π}}^2}{{\mathrm{\τ}}^3}{(l_d-l_q)}^3(3R_s+\frac{3B{l}_d}{2\mathrm{\Λg}})b=\frac{81{\mathrm{\π}}^3}{{\mathrm{\τ}}^3}{\mathrm{\ψ}}_m{(l_q-l_d)}^2(3R_s+\frac{7B{l}_d-l_{q}B}{4\mathrm{\Λg}})$ $c=\frac{243{\mathrm{\π}}^3}{{\mathrm{\τ}}^3}{\mathrm{\ψ}}_m^2(l_q-l_d)(\frac{B{l}_q-3B{l}_d}{4\mathrm{\Λg}}-R_s),d=\frac{81{\mathrm{\π}}^3}{{\mathrm{\τ}}^3}{\mathrm{\ψ}}_m^2(R_s+\frac{5B{l}_d-3B{l}_q}{4\mathrm{\Λg}}),$ $e=\frac{27{\mathrm{\π}}^2{\mathrm{\ψ}}_m^{3}B}{4\mathrm{\Λg}{\mathrm{\τ}}^2}+\frac{9\mathrm{\π}}{\mathrm{\τ}}{F}_{\mathrm{em}}^2(l_q-l_d)(R_s+\frac{B{l}_q}{2\mathrm{\Λg}}),$ L _dfor d axle inductance, l _qfor q axle inductance, perform step 5 afterwards);

5) switch i is controlled according to additional _d=a (e) i ₁+ { 1-a (e) } i ₂carry out the switching of control model, a (e) is switching factor, if v _s-v=e velocity measuring, its v _sfor given speed, v is motor feedback speed, and p switches point value for presetting.As | e|>p, for starting, stop and speed governing movement segment time, then a (e)=1, i ₁=i _d=0, namely use i _dthe Hysteresis Current vector control system of=0 controls motor, does not control the vertical force of motor; Otherwise, during for stable state fortune condition, a (e)=0, i ₂=i _d, namely control motor by optimum d shaft current, perform step 6 afterwards);

6) described optimum d, q shaft current is injected to Hysteresis Current vector control system, by vertical force controller at the constant lower vertical force to flux-reversal permanent-magnetism linear motor of maintenance thrust $F_v=\frac{3}{4\mathrm{\Λg}}[{\mathrm{\ψ}}_d{i}_d+{\mathrm{\ψ}}_q{i}_q]$ Change, this method terminates.

Inject at Hysteresis Current vector control system minimum copper loss and the vertical force that described optimum d, q shaft current can obtain flux-reversal permanent-magnetism linear motor to during motor stable state by above, thus lifting motor operating efficiency.

As shown in Figure 3, on the flux-reversal permanent-magnetism linear motor drive system basis of Hysteresis Current vector control, in conjunction with above-mentioned vertical force method for optimally controlling, can obtain the corresponding flux-reversal permanent-magnetism linear motor vertical force control system as Fig. 2, this control system comprises PI speed regulator 1, vertical force controller module 2, control switch 3,2r/3s conversion (rotor rotates static three phase inversion of two-phase/stator) module 4, Hysteresis Current PWM module 5, power conversion circuit 6, flux-reversal permanent-magnetism linear motor motor 7, motor speed and position detecting module 8.According to speed v and the v of actual measurement motor _sfor given speed, obtain speed difference e; This speed difference, by PI speed regulator 1, obtains required electromagnetic push value F _em; Then by vertical force controller module 2, correspondence and F can be drawn respectively _emoptimum vertical force control under ac-dc axis current reference value i _d(i2), i _qand i _d(i1) i under the control of=0 _q; Detect motor by control switch 3 again and whether reach steady operation, export the ac-dc axis electric current under condition of meeting the tendency mutually; Do 2r/3s conversion through module 4, obtain the three-phase windings current i A under stator rest frame, iB, iC; Carry out stagnant chain rate comparatively with three-phase windings real-time current value of feedback ia, ib, ic through Hysteresis Current PWM module 5, obtain power electronic device IGBT conducting cut-off signals Sa, Sb, Sc in power conversion circuit 6, thus provide three-phase current to motor; Real-time Feedback speed v and the mover shift position X of motor is calculated, for closed-loop control and the corresponding calculating of speed ring by motor speed and position detecting module 8.

Fig. 4 to Fig. 8 is motor properties value, adopts id=0 to control, adopt optimum d, q Current Control after 0.07s before 0.07s.Visible when motor steady operation and under keeping thrust 260N (Fig. 8), when 0.07s, d, q electric current (Fig. 5) changes accordingly, three-phase current (Fig. 6) also reduces thereupon, namely copper loss is reduced, vertical force (Fig. 7) is down to 510N by 633N simultaneously, reduces 19.4%.The control strategy that simulation results show the present invention proposes significantly reduces the vertical force of flux-reversal permanent-magnetism linear motor, and the thrust fan-out capability simultaneously maintaining again motor is constant, improves operating efficiency.

Claims (1)

1. a vertical force control method for flux-reversal permanent-magnetism linear motor, is characterized in that step comprises:

1) adopt electromagnetic force in linear electric motors Z-direction and vertical force are obtained to the method for maxwell's electromagnetic force tensor surface integration, then push away by finite element simulation or pressure sensor actual measurement the vertical force drawing flux-reversal permanent-magnetism linear motor Ψ _d, Ψ _qbe respectively motor straight, quadrature axis magnetic linkage, Λ is the magnetic leakage factor of motor, and g is the air gap of motor, performs step 2 afterwards);

2) the frictional force F caused by vertical force is determined _f=BF _v, B is rolling resistance of wheel coefficient, performs step 3 afterwards);

3) according to set additional electromagnetic thrust with additional copper loss and the frictional force F that vertical force causes _fset up auxiliary function formula $h(i_d,i_q,\mathrm{\λ})=P_{cu}+F_f+\mathrm{\λ}\[F_{em}-\frac{3\mathrm{\π}}{\mathrm{\τ}}({\mathrm{\ψ}}_d{i}_q-{\mathrm{\ψ}}_q{i}_d)\],$ τ is motor secondary pole span, R _sfor the resistance of armature winding, λ is Lagrange multiplier, d shaft current i _d, q shaft current i _q, perform step 4 afterwards);

4) by auxiliary function respectively to d shaft current i _d, q shaft current i _qask partial derivative with Lagrange multiplier λ and make it be zero, drawing optimum d shaft current

$i_d=\frac{-b}{4a}-\frac{1}{2}\sqrt{\frac{b^2}{4a^2}-\frac{2c}{3a}+\mathrm{\σ}}-\frac{1}{2}\sqrt{\frac{b^2}{2a^2}-\frac{4c}{3a}-\mathrm{\σ}-\frac{\frac{-b^3}{a^3}+\frac{4bc}{a^2}-\frac{8d}{a}}{4\sqrt{\frac{b^2}{4a^2}-\frac{2c}{3a}}+\mathrm{\σ}}},$ Optimum q shaft current $i_q=\frac{F_{em}^2\mathrm{\τ}}{3\mathrm{\π}({\mathrm{\ψ}}_d-l_q{i}_d)}$ Its

$\mathrm{\σ}=\frac{\sqrt[3]{2}{\mathrm{\σ}}_1}{3a\sqrt[3]{{\mathrm{\σ}}_2+\sqrt{-4{\mathrm{\σ}}_1^3+{\mathrm{\σ}}_2^2}}}+\frac{\sqrt[3]{{\mathrm{\σ}}_2+\sqrt{-4{\mathrm{\σ}}_1^3+{\mathrm{\σ}}_2^2}}}{3\sqrt[3]{2}a},$ σ ₁＝c ²-3bd+12ae ₀，σ ₂＝2c ³-9bcd+27ad ²+27eb ²-72ace ₀，

$a=\frac{27{\mathrm{\π}}^3}{{\mathrm{\τ}}^3}{(l_d-l_q)}^3(3R_s+\frac{3{\mathrm{Bl}}_d}{2\mathrm{\Λ}g})b=\frac{81{\mathrm{\π}}^3}{{\mathrm{\τ}}^3}{\mathrm{\ψ}}_m{(l_q-l_d)}^2(3R_s+\frac{7{\mathrm{Bl}}_d-l_{q}B}{4\mathrm{\Λ}g})$ $c=\frac{243{\mathrm{\π}}^3}{{\mathrm{\τ}}^3}{\mathrm{\ψ}}_m^2(l_q-l_d)(\frac{{\mathrm{Bl}}_q-3{\mathrm{Bl}}_d}{4\mathrm{\Λ}g}-R_s),d=\frac{81{\mathrm{\π}}^3}{{\mathrm{\τ}}^3}{\mathrm{\ψ}}_m^2(R_s+\frac{5{\mathrm{Bl}}_d-3{\mathrm{Bl}}_q}{4\mathrm{\Λ}g}),$ $e_0=\frac{27{\mathrm{\π}}^2{\mathrm{\ψ}}_m^{3}B}{4{\mathrm{\Λg\τ}}^2}+\frac{9\mathrm{\π}}{\mathrm{\τ}}{F}_{em}^2(l_q-l_d)(R_s+\frac{{\mathrm{Bl}}_q}{2\mathrm{\Λ}g}),$ L _dfor d axle inductance, l _qfor q axle inductance, perform step 5 afterwards);

5) switch i is controlled according to additional _d=a (e) i ₁+ { 1-a (e) } i ₂carry out the switching of control model, a (e) is switching factor, if v _s-v=e velocity measuring, its v _sfor given speed, v is motor feedback speed, and p switches point value for presetting; As | e|>p, for starting, stop and speed governing movement segment time, then a (e)=1, i ₁=i _d=0, namely use i _dthe Hysteresis Current vector control system of=0 controls motor, does not control the vertical force of motor; Otherwise, during for stable state fortune condition, a (e)=0, i ₂=i _d, namely control motor by optimum d shaft current, perform step 6 afterwards);

6) described optimum d, q shaft current is injected to Hysteresis Current vector control system, by vertical force controller at the constant lower vertical force to flux-reversal permanent-magnetism linear motor of maintenance thrust change, this method terminates.