CN102299678B - Vector control device for alternating current motor - Google Patents

Abstract

The invention provides a vector control device for an alternating current motor. By the device, automatically calculated optimal damping operation amount can be obtained, and a damping control part of the device is set without gain, so that the adjustment operation of a control system is simplified. The device comprises a vector control part (30) for performing vector control on the alternating current motor (6) according to a current instruction or torque instruction, and a damping control part (40) for calculating the damping operation amount which inhibits the change of voltage Efc of a capacitor, wherein the damping control part (40) calculates the change proportion of the voltage Efc of the capacitor, operates the current instruction or torque instruction of the vector control part (30) through the damping operation amount corresponding to the change proportion, and controls an inverter (4), so that for the change of the voltage Efc of the capacitor, current flowing through the inverter (4) changes in a change inhibiting direction.

Description

The vector control apparatus of alternating current motor

The application is that denomination of invention is that " vector control apparatus of alternating current motor ", international filing date are the divisional application that August 29, application number in 2006 are the application for a patent for invention of 200680055710.8 (international application no is PCT/JP2006/316961).

Technical field

The present invention relates to alternating current motor to carry out the vector control apparatus of the alternating current motor of vector control.

Background technology

The technology that uses inverter to carry out vector control to alternating current motor is widely used in industrial circle.This technology is just widely used in electric railway from the past, but known in the time that galvanic electric railway is used said system, absorbing the reactor of use by the high order harmonic component of DC side that is configured in inverter and the LC filter circuit that capacitor forms can produce electric oscillation, the both end voltage (condenser voltage) of capacitor can be vibrated, the control meeting of motor is unstable, discloses to some extent at non-patent literature 1, non-patent literature 2 for suppressing this unsettled damping control method.

Non-patent literature 1: Kimura is clear waits people's work " about the investigation of the stabilisation of the control system for electric vehicle of induction motor drive ", the electric paper will D of association, No. 3,110 volume, put down into 2 years, 291st～300 pages

Non-patent literature 2: people's works " investigation of the magnetic flux of the control system without IM velocity transducer while driving about rolling stock " such as nearly rattan Gui one youth, electric association semiconductor power study on the transformation is understood data, SPC03-100,2003 years, 69th～74 pages

Non-patent literature 1, non-patent literature 2 are all the voltage that adopts additional detected capacitor, utilize band pass filter (hereinafter referred to as BPF) to extract oscillating component, adjust phase place, the damping control part of the formation that the damping operational ton that obtains of gain and difference frequency instruction (non-patent literature 1) or torque instruction (non-patent literature 2) be added, the structure of the electric oscillation of inhibition LC filter circuit will be multiplied by.

In addition, non-patent literature 1 is the example at the motor control system of use difference frequency control, and non-patent literature 2 is the examples at the motor control system of use vector control.

Summary of the invention

The control system that above-mentioned damping control part is in the past formed by BPF and gain forms.About the setting of BPF, only need to set its constant, make there is no phase delay and detect the resonance frequency component of reactor and capacitor, but about the setting of gain, if it is too many lower than optimum value to gain, the effect that suppresses electric oscillation is good not, Ruo Taigao, gain can continue to produce the high-frequency electrical vibration higher than above-mentioned resonance frequency, so must be set as its middle optimum value.

But as shown in non-patent literature 1, it is extremely narrow that the electric oscillation that can effectively suppress LC filter circuit realizes the optimum gain scope of stabilisation, be not easy to adjust.In non-patent literature 1, attempted, with frequency-domain analysis control system, calculating best gain setting, but it calculates process more complicated, and still need the operation in control system by the gain setting calculating.In addition, as shown in non-patent literature 1, owing to using the constant of motor in the formula that calculates process, so if the kind of the motor being connected with inverter changes, must again calculate the gain corresponding with it and set.The gain setting of damping control part like this, in the past expends time very much.

The present invention does for addressing the above problem, and its objective is the vector control apparatus that a kind of alternating current motor is provided, and this device can be simplified the adjustment operation of the control system of the electric oscillation for suppressing LC filter circuit.

The present invention has at direct current source the LC filter circuit being formed by reactor and capacitor, by the both end voltage of above-mentioned capacitor (condenser voltage) being converted to the inverter of the alternating voltage of optional frequency, alternating current motor is carried out to the vector control apparatus of the alternating current motor of vector control

Comprise: according to current-order or torque instruction, above-mentioned alternating current motor is carried out to the vector control portion of vector control; And calculate the damping control part of damping operational ton of the variation that suppresses above-mentioned condenser voltage, above-mentioned damping control part calculates the variation ratio of above-mentioned condenser voltage, according to operating above-mentioned current-order or the above-mentioned torque instruction of above-mentioned vector control portion with the corresponding above-mentioned damping operational ton of this variation ratio, control above-mentioned inverter, make the variation for above-mentioned condenser voltage, the electric current that flows through above-mentioned inverter changes to the direction that suppresses this variation.

According to the vector control apparatus of alternating current motor involved in the present invention, can simplify the adjustment operation that suppresses the control system that the electric oscillation of LC filter circuit uses.

Brief description of the drawings

Fig. 1 is the block diagram that represents the structure of the vector control apparatus of the alternating current motor of embodiment of the present invention 1.

Fig. 2 is illustrated in the key diagram that is connected with the circuit of the inverter that is controlled as permanent power on the LC filter being connected with DC power supply.

Fig. 3 is the block diagram of the system transter of presentation graphs 2.

Fig. 4 is illustrated in the key diagram that is connected with the circuit of the load being made up of resistance on the LC filter being connected with DC power supply.

Fig. 5 is the block diagram of the system transter of presentation graphs 4.

Fig. 6 is the key diagram of the relation of the signal of the each portion of damping control part of explanation embodiment of the present invention 1.

Fig. 7 represents the action simulation result of the vector control apparatus of the alternating current motor of embodiment of the present invention 1.

Label declaration

1: DC power supply

2: reactor

3: capacitor

4: inverter

5a～5c: current detector

6: alternating current motor

7: speed detector

8:q shaft current instruction generating unit

9:d shaft current instruction generating unit

10,11: subtracter

12:q shaft current controller

13:d shaft current controller

14: the non-interference calculating part of voltage

17,18: adder

19: difference frequency instruction generating unit

20: adder

21: integrator

22:dq axle-three-phase coordinate converter

23: three-phase-dq axial coordinate converter

24: multiplier

30: vector control portion

40: damping control part

41: high pass filter

42: low pass filter

43: low pass filter

44: adder

45: divider

46: subtracter

47: switch

48: square calculator

49: amplitude limiter (limiter)

50: vector control apparatus

60: resistance

Embodiment

Execution mode 1

Fig. 1 is the block diagram that represents the structure of the vector control apparatus of the alternating current motor of embodiment of the present invention 1.

As shown in Figure 1, main circuit has DC power supply 1 and flows out to mains side in order to suppress higher harmonic current, the LC filter circuit being formed by reactor 2 and capacitor 3; Have and utilize the inverter 4 of the alternating voltage that is converted to optional frequency that the both end voltage of above-mentioned capacitor 3 (condenser voltage) Efc is converted to interchange, alternating current motor 6 is carried out to the vector control apparatus 50 of vector control.

Vector control apparatus 50 is made up of vector control portion 30 and damping control part 40, input from detect alternating current motor 6 rotary speed speed detector 7 signal ω r, from signal Iu, Iv, Iw, the voltage Efc of capacitor 3 of current detector 5a～5c that detects motor current.

In addition, as long as 2 phases are set because current detector is minimum, residue 1 just can calculate mutually as calculated, so also can form like this.

In addition, speed detector 7 is not set, calculates the rotary speed of alternating current motor 6 the Speedless sensor vector control mode calculating and obtain practical application yet, do not need in this case speed detector 7.

And, as alternating current motor 6, describe with the structure example that uses induction motor below, but the damping control part 40 that the present invention discloses is also useful in the time using synchronous motor as alternating current motor 6.

Next the structure of vector control portion 30 is described.

Vector control portion 30 as d axle, to carry out the control of alternating current motor in the dq axle rotating coordinate system defining as q axle with the orthogonal axle of above-mentioned d axle, carries out so-called vector control at the axle using consistent with the secondary magnetic flux axle of alternating current motor 6.

Input torque elementary instruction Tm0*, the secondary magnetic flux instruction Φ 2*, the U phase current Iu being detected by current detector 5a～5c, V phase current Iv, the W phase current Iw that are generated by upper control part (not shown) to vector control portion 30, control the torque Tm that alternating current motor 6 produces, make it consistent with the torque instruction Tm* (generation method illustrates below) being generated by torque elementary instruction Tm0*.

Next the structure of each functional block of vector control portion 30 inside is described.

In q shaft current instruction generating unit 8, d shaft current instruction generating unit 9, torque instruction Tm*, the secondary magnetic flux instruction Φ 2* being multiplied each other by the torque elementary instruction Tm0* that the control part from outside (not shown) is inputted and damping operational ton DAMPCN (aftermentioned), the circuit constant of alternating current motor 6, calculate d axle (excitation component) current-order Id*, q axle (torque component) current-order Iq* according to following formula (1) and (2).

Wherein, in formula (1) and (2), L2 is the secondary self-induction of motor, is expressed by L2=M+l2.M is that mutual inductance, l2 are that secondary leakage inductance, s are differential operators, and PP is the number of pole-pairs of alternating current motor 6, and R2 is the secondary resistance of alternating current motor 6.

Iq*＝(Tm*/(Φ2*·PP))·(L2/M) ......(1)

Id*＝Φ2*/M+L2/(M·R2)·sΦ2* ......(2)

In slip angular frequency instruction generating unit 19, by the circuit constant of d shaft current instruction Id*, q shaft current instruction Iq* and alternating current motor 6, calculate the slip angular frequency instruction ω s* that offers alternating current motor 6 according to following formula (3).

ωs*＝(Iq*/Id*)·(R2/L2) ......(3)

Be the result that anglec of rotation frequencies omega r is added through adder 20 by the slip angular frequency instruction ω s* calculating by this formula (3), the output that is arranged on the speed detector 7 of the axle head of alternating current motor 6, the inverter angular frequency of exporting as inverter 4, using inverter angular frequency through the result of integrator 21 integrations the phase angle θ as coordinate transform, input to dq axle-three-phase coordinate converter 22, three-phase-dq axial coordinate converter 23.

In three-phase-dq axial coordinate converter 23, U phase current Iu, V phase current Iv, the W phase current Iw that current detector 5a～5c is detected is transformed to d shaft current Id and the q shaft current Iq on the dq coordinate being calculated by following formula (4).

[several 1]

$\left(\begin{array}{c}\mathrm{Iq}\\ \mathrm{Id}\end{array}\right)=\sqrt{\frac{2}{3}}\left(\begin{array}{ccc}\cos \mathrm{\θ}& \cos (\mathrm{\θ}-\frac{2}{3}\mathrm{\π})& \cos (\mathrm{\θ}+\frac{2}{3}\mathrm{\π})\\ \sin \mathrm{\θ}& \sin (\mathrm{\θ}-\frac{2}{3}\mathrm{\π})& \sin (\mathrm{\θ}+\frac{2}{3}\mathrm{\π})\end{array}\right)\·\left(\begin{array}{c}\mathrm{Iu}\\ \mathrm{Iv}\\ \mathrm{Iw}\end{array}\right)......\left(4\right)$

Subtracter 10 calculates the poor of q shaft current instruction Iq* and q shaft current Iq, result is inputed to the q shaft current controller 12 of next stage.Q shaft current controller 12 carries out proportional plus integral control to the value of input, output q shaft voltage offset qe.

Subtracter 11 calculates the poor of d shaft current instruction Id* and d shaft current Id, result is inputed to the d shaft current controller 13 of next stage.D shaft current controller 13 carries out proportional integral amplification to the value of input, output d shaft voltage offset de.

Q shaft current error qe, d shaft current error de are expressed by following formula (5), (6).

In addition, in following formula, s is differential operator, and K1 is proportional gain, and K2 is storage gain.

qe＝(K1+K2/s)·(Iq*-Iq)......(5)

de＝(K1+K2/s)·(Id*-Id)......(6)

In the non-interference calculating part 14 of voltage, by the circuit constant of d shaft current instruction Id*, q shaft current instruction Iq*, alternating current motor 6, calculate d axle feed-forward voltage Ed*, q axle feed-forward voltage Eq* according to following formula (7), (8).

Wherein, in formula (7) and formula (8), σ is by σ=1-M ²/ (L1L2) the leakage inductance coefficient of definition.In addition, L1 is a self-induction of motor, utilizes L1=M+l1 to calculate.L2 is secondary self-induction, utilizes L2=M+l2 to calculate.(l1 is a leakage inductance, and l2 is secondary leakage inductance)

Ed*＝-ω·L1·σ·Iq*+(M/L2)·sΦ2*......(7)

Eq*＝ω·L1·σ·Id*+(ω·M·Φ2*)/L2......(8)

In adder 17,18, using the result of q shaft voltage offset qe and q axle feed-forward voltage Eq* addition as q shaft voltage instruction Vq*, using the result of d shaft voltage offset de and d axle feed-forward voltage Ed* addition as d shaft voltage instruction Vd*, input to respectively dq axle-three-phase coordinate converter 22.

Q shaft voltage instruction Vq*, d shaft voltage instruction Vd* are expressed by following formula (9), (10).

Vq*＝Eq*+qe......(9)

Vd*＝Ed*+de......(10)

Finally, utilize dq axle-three-phase coordinate converter 22, generated voltage instruction Vu*, Vv*, the Vw* of three-phase by q shaft voltage instruction Vq* and d shaft voltage instruction Vd*, control inverter 2.

By like this, vector control portion 6 implements to be attached with the vector control of Current Feedback Control, so that the electric current of actual alternating current motor 6, q shaft current Iq, d shaft current Id Id* is consistent with the q shaft current instruction Iq*, the instruction of d shaft current that are calculated by torque instruction Tm* and secondary magnetic flux instruction Φ 2*, alternating current motor 6 is exported the torque Tm consistent with torque instruction Tm* to be rotated.

In addition, because this control action is substantially identical with known vector control, therefore detailed action specification is omitted.

Next illustrate that main portion of the present invention is the structure of damping control part 40.

Illustrating before the damping control part 40 shown in Fig. 1, simple declaration produces the reason of electric oscillation and suppresses principle as the electric oscillation of the LC filter circuit of the basis of the structure of the damping control part shown in embodiment of the present invention 1 at LC filter circuit.

Fig. 2 is illustrated in the figure that connects the circuit of the inverter 4 that is controlled as permanent power on the LC filter being connected with DC power supply 1.Fig. 2 is the performance of the system shown in reduced graph 1.

As shown in Figure 2, in DC power supply 1, connect the LC filter circuit being formed by reactor 2, capacitor 3, on capacitor 3, connect and drive the inverter 4 of controlling alternating current motor 6.Reactor 2 is made up of inductance composition L and resistance components R.The electrostatic capacitance of capacitor 3 is C.

In addition, there is variation even if inverter 4 has the condenser voltage of being controlled as Efc, also can make the output of alternating current motor 6 maintain necessarily, have and be controlled as the structure for the variation of condenser voltage Efc with the characteristic that keeps permanent power.Even if be namely controlled as Efc variation, the input power Pinv of inverter 4 also can not change.

In the system of the Fig. 2 forming like this, from DC power supply 1 unilateral observation to inverter 4 there is negative resistance property.

If negative resistance property refers to condenser voltage Efc rising, the input current Idc of inverter reduces; If condenser voltage Efc increases, the characteristic that the input current Idc of inverter reduces is contrary with the relation property of change in voltage with the curent change of common resistance (positive resistance).In addition, as general knowledge, known common resistance (positive resistance) electric current in the time that voltage rises increases, and when voltage reduces, electric current reduces.

As mentioned above, the direct current portion of the system shown in Fig. 2 demonstrates negative resistance property, and condenser voltage Efc rises, and the input current Idc of inverter reduces, so become the action that promotes that condenser voltage Efc increases; Otherwise condenser voltage Efc reduces, the input current Idc of inverter increases, so become the action that promotes that condenser voltage Efc reduces.Therefore, the variation of limiting capacitance device voltage Efc is invalid, and the electric oscillation of LC filter circuit continues to increase, near the condenser voltage Efc persistent oscillation resonance frequency of LC filter.It is more than qualitative explanation.

Next, obtain the system transter of Fig. 2, it is evaluated, so that phenomenon described above is quantitatively illustrated.

First, obtain the transfer function from direct voltage Es to condenser voltage Efc by the system of Fig. 2.

As mentioned above, inverter 4 is controlled makes it and is output as necessarily.Now, the relational expression of the input power Pinv of inverter and condenser voltage Efc, input current of inverter Idc is following formula (11).

[several 2]

EfcIdc=Pinv (=certain) ... (11)

Above-mentioned relation is nonlinear, therefore needs to carry out linearisation.If the operating point of establishing is now Efc0, Idc0, following formula (12) is set up in its vicinity.

[several 3]

$\mathrm{Idc}=-\frac{\mathrm{Pinv}\·(\mathrm{Efc}-\mathrm{Efc}0)}{{\mathrm{Efc}0}^2}+\mathrm{Idc}0......\left(12\right)$

From the system transter block diagram shown in Fig. 2 and the known Fig. 2 of formula (12) as shown in Figure 3.

Transfer function block diagram as shown in Figure 3 draws, the closed loop transfer function, G (s) from direct voltage Es to condenser voltage Efc is shown in following formula (13).

[several 4]

$G\left(s\right)=\frac{\frac{1}{C\·L}}{s^2+(\frac{R}{L}-\frac{\mathrm{Pinv}}{C\·{\mathrm{Efc}0}^2})\·s-\frac{1}{C\·L}(\frac{R\·\mathrm{Pinv}}{{\mathrm{Efc}0}^2}-1)}......\left(13\right)$

In order to make this transfer function G (s) stable, all limits of G (s) need to be for negative., the denominator of G (s), all solutions of the characteristic equation shown in following formula (14) need to be for negative.

[several 5]

$s^2+(\frac{R}{L}-\frac{\mathrm{Pinv}}{C\·{\mathrm{Efc}0}^2})\·s-\frac{1}{C\·L}(\frac{R\·\mathrm{Pinv}}{{\mathrm{Efc}0}^2}-1)=0......\left(14\right)$

If establishing the solution of above formula is α, β, owing to both needing for negative, so as making the stable condition of G (s), can derive following formula (15), (16).Can obtain following formula (15), (16) according to the relation of solution and coefficient.

[several 6]

$\mathrm{\&alpha;}+\mathrm{\&beta;}=-(\frac{R}{L}-\frac{\mathrm{Pinv}}{C\&CenterDot;{\mathrm{Efc}0}^2})<0......\left(15\right)$

$\mathrm{\&alpha;}\&CenterDot;\mathrm{\&beta;}=-\frac{1}{C\&CenterDot;L}(\frac{R\&CenterDot;\mathrm{Pinv}}{{\mathrm{Efc}0}^2}-1)>0......\left(16\right)$

Formula (16) does not comprise Useful Information, therefore can ignore herein.Formula (15) is rewritten as to following formula (17).

[several 7]

$R>\frac{L}{C}\&CenterDot;\frac{\mathrm{Pinv}}{{\mathrm{Efc}0}^2}......\left(17\right)$

From formula (17), L is less, and C is larger, and Pinv is less, and EfcO is larger, makes the required R of system stabilityization less.

As an example, be the condition substitution formula (17) of L=12mH, c=6600 μ F, Pinv=1000KW, Efc0=1500v by motor vehicle driving with the prevailing value of inverter system, the value that can make the R of system stability is R > 0.8 (Ω).

But the resistive component conventionally existing in DC side is the small value of tens m Ω left and right, is difficult to meet formula (17), it is unstable that system becomes, and LC filter circuit can produce vibration.

That is to say, in the circuit shown in Fig. 2, only otherwise additionally meet the resistance of formula (17) or cannot realize stable in control, condenser voltage Efc will oscillation and divergence.

In fact, additional resistance can cause device maximization, loss to increase, and controls the above method of stabilisation so need to realize, and its concrete prior art is for example shown in non-patent literature 1, non-patent literature 2.

Below with above described in similarly quantitatively illustrate that load is the situation of resistance (common positive resistance) load.

Fig. 4 is the figure that is illustrated in the circuit of the load that on the LC filter being connected with DC power supply 1, connection is made up of resistance 60.With the circuit comparison shown in Fig. 2, it is the circuit that inverter 4 and alternating current motor 6 are replaced by resistance 60.The resistance value of in addition, establishing resistance 60 is R0.

System transter block diagram shown in Fig. 4 as shown in Figure 5.

According to Fig. 5, be shown in following formula (18) from the voltage Es of DC power supply 1 to the closed loop transfer function, Gp (s) of condenser voltage Efc.

[several 8]

$\mathrm{Gp}\left(s\right)=\frac{\frac{1}{L\&CenterDot;C}}{s^2+(\frac{1}{C\&CenterDot;R0}+\frac{R}{L})\&CenterDot;s+\frac{1}{C\&CenterDot;L}\&CenterDot;(\frac{R}{R0}+1)}......\left(18\right)$

The characteristic equation of closed loop transfer function, Gp (s) shown in formula (18) is shown in following formula (19).

[several 9]

$s^2+(\frac{1}{C\&CenterDot;R0}+\frac{R}{L})\&CenterDot;s+\frac{1}{C\&CenterDot;L}\&CenterDot;(\frac{R}{R0}+1)=0......\left(19\right)$

Due to R > 0, all solutions of the characteristic equation shown in formula (19) all meet for negative condition.Putting known load from this is all-the-time stable while being made up of resistance 60.

As described above, on the known LC filter being connected with DC power supply 1, the circuit of contact resistance 60 is all-the-time stable.The present invention is conceived to this principle, it is characterized in that control inverter 4, the characteristic equivalence shown in while making its oscillating component for condenser voltage Efc and contact resistance 60.

The following describes shown in Fig. 4 the characteristic of the circuit of contact resistance 60 in the output of LC filter.

In the circuit of Fig. 4, if under the condition of condenser voltage Efc to resistance 60 inflow current Idc, the power P R on resistance 60 is shown in following formula (20).

PR＝Efc·Idc......(20)

Condenser voltage Efc variation, while becoming originally n times, the electric current I dc flowing through at resistance 60 becomes n doubly too, and therefore now the power P Rn on resistance 60 is shown in following formula (21).

PRn＝n·Efc·n·Idc＝n ²·Efc·Idc＝n ²·PR......(21)

Be power P Rn on known resistance 60 and square being directly proportional of the variation ratio of condenser voltage Efc.

From this point, by control inverter 4, the relation of formula (21) is set up, can make inverter 4 move as thering is positive resistance characteristic for the variation of condenser voltage Efc.

But the output of alternating current motor 6 can be expressed by the speed FM of alternating current motor 6 × output torque Tm, while ignoring loss, this value equates with the input power pinv of inverter 4, so following formula (22) is set up.

Pinv＝FM·Tm......(22)

For inverter 4 is moved as having positive resistance characteristic for the variation of condenser voltage Efc, power P invn when condenser voltage Efc is increased to n times is the same with formula (21), as long as meet the relation of following formula (23).

Pinvn＝n ²·Pinv＝n ²·FM·Tm......(23)

Herein, the speed FM of alternating current motor 6 is and the value of the speed respective change of motor vehicle.On the other hand, the resonance frequency of the LC filter circuit that damping control part 40 is processed is 10Hz～20Hz, is scaled the cycle, and the time is 50ms～100ms.From above, can be considered very short time with respect to the velocity variations of motor vehicle the cycle of oscillation of LC filter circuit, therefore, on the basis of structure of considering damping control part 40, can suppose that the speed FM of alternating current motor 6 is for certain.

So in the time that condenser voltage Efc is increased to n times, the torque Tm that makes alternating current motor 6 if control is n ²doubly, can make square variation pro rata of the variation ratio of inverter input power Pinv and condenser voltage Efc.

Adopt by the variation ratio of condenser voltage Efc square value and the torque instruction Tm* formation that multiplies each other.

By like this, for the variation part of condenser voltage Efc, inverter 4 has positive resistance characteristic, and the electric oscillation that can suppress LC filter circuit makes its stabilisation.

Next the concrete structure of method described above is described with reference to Fig. 1 and Fig. 6.

Fig. 6 is the figure of the relation of the signal of damping control part 40 inside of explanation embodiment of the present invention 1.

To the voltage Efc of damping control part 40 input capacitors 3, branch into two systems.

On the other hand, utilize high pass filter (hereinafter referred to as HPF) 41, the unwanted high fdrequency component of low pass filter (hereinafter referred to as LPF) 43 filtering, unwanted low frequency component, calculate near the oscillating component Efca of resonance frequency that only extracts LC filter circuit.For example, as shown in Fig. 6 (a), condenser voltage Efc centered by 1500V in the time of the range oscillation of 1650V～1350V, Efca become as Fig. 6 (b) scope of be shown in+150V～-150V and the oscillating component same-phase of condenser voltage Efc the signal that changes.

On the other hand, utilize LPF42 only to extract DC component, as DC component Efcd.

HPF41, LPF42, LPF43 are the filters being made up of time lag of first order key element, because its structure is known, so explanation is omitted.Can certainly be filter more than secondary, but this can cause the structure complicated of filter.

The effect of HPF41, LPF43 is described herein.

The reason that needs LPF43 is to be included in condenser voltage Efc in order to remove, and brings the high fdrequency component of disturbance to control system.But, the lower limit of wishing the high fdrequency component of removing is hundreds of Hz, the approaching object as damping control, the resonance frequency band (being generally 10～20Hz left and right) of LC filter, if therefore only use LPF43 to remove high fdrequency component, the resonance frequency component that is included in the LC filter in oscillating component Efca can be affected, phase delay can be produced, thus unsatisfactory.

Therefore, append HPF41 by series connection, constitute filter with LPF43, can guarantee with independent use LPF43 time, same high fdrequency component is removed characteristic, improves the phase delay of the resonance frequency component that is included in the LC filter in oscillating component Efca simultaneously.In addition, about the characteristic of HPF41, LPF43, comparatively it is desirable to make gain is that 1 frequency is consistent with the frequency of oscillation (10Hz～20Hz) of LC filter.

On the oscillating component Efca calculating as mentioned above, add DC component Efcd by adder 44, set it as the condenser voltage Efcad (Fig. 6 (c)) after filter.

In addition, by with divider 45 by the condenser voltage Efcad after filter divided by DC component Efcd, calculate the variation ratio Efcfp of condenser voltage Efc.

Then,, in the time of alternating current motor 6 electronic running, Efcfp former state is inputed to square calculator 48.

In addition, in the time of alternating current motor 6 regeneration operating, utilize switch 47 to select with subtracters 46, from the 2 regeneration operating reverse signal Efcfn that deduct the variation ratio Efcfp of condenser voltage Efc, to input to square calculator 48.This is due to when alternating current motor 6 regeneration operating, and the direction of power is contrary during with alternating current motor 6 electronic running, if condenser voltage Efc increases, and need to be in the operation of the direction that regenerating power is reduced; If condenser voltage Efc reduces, need to be in the operation of the direction that regenerating power is increased, regeneration operating is by the signal of the phasing back of the variation ratio Efcfp of condenser voltage Efc (Fig. 6 (d)) with reverse signal Efcfn.

Square calculator 48 square inputs to amplitude limiter 49 by the variation ratio Efcfp of condenser voltage Efc or regeneration operating with reverse signal Efcfn.

In amplitude limiter 49, after as required the upper limit, lower limit being arbitrary value, export as damping operational ton DAMPCN (Fig. 6 (e)) to vector control portion 30.In amplitude limiter 49, for example, be set as wishing that restriction follows damping control, the situation of the transition variation of the torque Tm of alternating current motor 6.

Finally, in vector control portion 30, damping operational ton DAMPCN and torque elementary instruction Tm0* being multiplied each other, is that torque instruction Tm* implements vector control according to its result.

Utilize the torque instruction Tm* generating like this to carry out vector control, with this, inverter 4 is moved, make inverter 4 be shown as positive resistance characteristic for the variation of condenser voltage Efc, the vibration of suppression capacitor voltage Efc, can realize the steady running of alternating current motor 6.

Fig. 7 is the action simulation result figure that represents the vector control apparatus of the alternating current motor of embodiment of the present invention 1.

Fig. 7 is illustrated in the structure shown in Fig. 1, and torque elementary instruction Tm0* is set as to about 500Nm, and when alternating current motor 6 is turned round, the voltage Es that makes DC power supply 1 is the waveform when changing taking cycle 500ms as one-level between 1000V at 800V.

As shown in Figure 7, do not implementing in the situation of damping control of the present invention (waveform on the right side of Fig. 7), in the time that every grade of the voltage Es of DC power supply 1 changes, condenser voltage Efc produces larger vibration, but implementing in the situation of damping control of the present invention (waveform in the left side of Fig. 7), although have the one-level of the voltage Es of direct current 1 to change known, condenser voltage Efc produces vibration hardly.

Can confirm the effectively vibration of suppression capacitor voltage Efc of damping control of the present invention according to Fig. 7.

As shown above, according to embodiment of the present invention 1, automatically calculate best damping operational ton DAMPCN, can form the damping control part of the setting that does not need gain itself.And, owing to not using the constant of alternating current motor 6 in the time calculating damping operational ton DAMPCN, so even if the type change of alternating current motor 6 does not need to adjust control system yet.

In the above description, to use induction motor to be illustrated as the situation of alternating current motor 6 as example, but for the vector control portion in the situation of this motor of use or other alternating current motors, also can use the structure of damping control part described above and the computational methods of damping operational ton.

In addition, in the structure shown in execution mode 1, damping operational ton DAMPCN and torque elementary instruction Tm0* multiply each other, but multiply each other and also can obtain same effect with q shaft current instruction Iq*.

In the present embodiment, according to the variation ratio n of condenser voltage, DANPCN=n in the time of electronic running ²calculate damping operational ton DAMPCN, in the time of regeneration, use DAMPCN=(2-n) ²calculate damping operational ton DAMPCN.Also can establish the fluctuation component of condenser voltage and the ratio of DC component is Δ n (=n-1), and according to the gain K that is greater than 0.5, in the time of electronic running, with DAMPCN=, (1+K* Δ n) ²calculate, in the time of regeneration, calculate with DAMPCN=1.

If ignore above items, for the variation of condenser voltage, the fluctuation component Δ Idc=DAMPCN/n of electric current that flows through power conversion device is as described below for 2 times of Δ n.When electronic running, (1+K Δ n) for Δ Idc= ²/ (1+ Δ is ≈ 1+ (2K-1) Δ n n).Therefore,, if K > 0.5, the electric current that flows through inverter when condenser voltage increases in the time of electronic running increases; The electric current that flows through inverter when condenser voltage reduces reduces.Can control inverter, make the variation for condenser voltage, the electric current that flows through inverter changes to the direction that suppresses variation, and the electric oscillation of LC filter circuit just can be stablized.

In addition, K is larger, and the effect of damping is larger, but the variation of torque can increase in the time that condenser voltage sharply changes.

In when regeneration, the sense of current that flows through inverter is contrary during with electronic running, even if inverter carries out permanent power action, also can not demonstrate negative resistance property.Therefore,, even in the time not carrying out damping operation (DAMPCN=1), it is unstable that the electric oscillation of LC filter circuit can not become yet.If (1-K Δ n) to make DAMPCN= ²deng, can make the electric oscillation of LC filter circuit decay sooner.Gain K when regeneration can be also value different during from electronic running.

The calculating formula of damping operational ton DAMPCN can not be 2 formulas of Δ n, can be also that the more than formula formula of 1 formula or 3 times or denominator and molecule have polynomial fraction of Δ n etc.In the linear approximation formula for small variations, if the coefficient of Δ n is greater than 1 in calculating formula when electronic running, in calculating formula when regeneration operating, the coefficient of Δ n is less than 0, can use any calculating formula.

In addition, the structure shown in above-mentioned execution mode 1 is an example of content of the present invention, and technical combinations that also can be known with other not departing from the scope of main points of the present invention, certainly can be omitted, change a part etc. and form.

And, the invention is not restricted to the vector control apparatus of the alternating current motor that electric railway uses, can certainly be applied in the various association areas such as automobile, elevator, electric power system.

Claims (3)

1. the vector control apparatus of an alternating current motor, there is the LC filter circuit being formed by reactor and capacitor at direct current source, by by the both end voltage of described capacitor, the inverter that is the condenser voltage alternating voltage that is converted to optional frequency carries out vector control to alternating current motor, this vector control apparatus is characterised in that, comprising:

According to current-order or torque instruction, described alternating current motor is carried out the vector control portion of vector control; And

Calculate the damping operational ton of the variation that suppresses described condenser voltage, described damping operational ton based on calculating operates described current-order or the described torque instruction of described vector control portion, control described inverter, make the variation for described condenser voltage, flow through the electric current of described inverter to the damping control part of the direction variation of the described variation of inhibition

The signal that described damping control part generates the square value of the variation ratio based on described condenser voltage is as damping operational ton.

2. the vector control apparatus of alternating current motor as claimed in claim 1, is characterized in that,

In the time of the electronic running of described alternating current motor, generate described damping operational ton, so that flowing through the electric current of described inverter while increasing, proper described condenser voltage increases, the electric current that flows through described inverter in the time that described condenser voltage reduces reduces.

3. the vector control apparatus of alternating current motor as claimed in claim 1 or 2, is characterized in that,

In the time of the regeneration operating of described alternating current motor, generate described damping operational ton, if with make described condenser voltage increase regenerating power reduce, increase if described condenser voltage reduces regenerating power.