CN102299678A - 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 dividing an application of August 29, application number in 2006 application for a patent for invention that is 200680055710.8 (international application no is PCT/JP2006/316961).

Technical field

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

Background technology

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

Non-patent literature 1: the clear work such as the people of grade of Kimura " investigation of the stabilisation of the control system for electric vehicle that drives about induction motor ", the electric paper will D of association, 110 No. 3, volumes, put down into 2 years, the 291st～300 page

Non-patent literature 2: people such as nearly rattan Gui one youth work " investigation of the magnetic flux of the control system of the no IM velocity transducer when driving about rolling stock ", electric association semiconductor power study on the transformation is understood data, SPC03-100,2003 years, the 69th～74 page

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

In addition, non-patent literature 1 is the use-case that makes at the motor control system that uses difference frequency control, and non-patent literature 2 is the use-cases that make at the motor control system that uses vector control.

Summary of the invention

Above-mentioned damping control part in the past is made of the control system that BPF and gain form.Setting about BPF, only need to set its constant, make the resonance frequency component that does not detect reactor and capacitor get final product with having phase delay, but setting about gain, if it is too many that gain is lower than optimum value, the effect that then suppresses electric oscillation is good inadequately, Ruo Taigao, gain then can continue to produce the high-frequency electrical vibration that is higher than above-mentioned resonance frequency, so must be set at its middle optimum value.

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

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 that is used to suppress the LC filter circuit.

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

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

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

Description of drawings

Fig. 1 is the block diagram of structure of vector control apparatus of the alternating current motor of expression 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 that is 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 that is made of resistance on the LC filter that is 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 relation of signal of each one of damping control part of explanation embodiment of the present invention 1.

Fig. 7 represents the action simulation result of 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: the 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 of structure of vector control apparatus of the alternating current motor of expression 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 that is formed by reactor 2 and capacitor 3; Have the inverter 4 that utilizes the alternating voltage be converted to optional frequency both end voltage (condenser voltage) Efc of above-mentioned capacitor 3 is converted to interchange, alternating current motor 6 is carried out the vector control apparatus 50 of vector control.

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

In addition, as long as because minimum 2 phases that are provided with of current detector, residue 1 just can be calculated mutually as calculated, so also can constitute like this.

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

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

Next the structure of vector control portion 30 is described.

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

Import by torque elementary instruction Tm0*, the secondary magnetic flux instruction Φ 2* of upper control part (not shown) generation, by the detected U phase current of current detector 5a～5c Iu, V phase current Iv, W phase current Iw to vector control portion 30, the torque Tm that control alternating current motor 6 produces makes it consistent with the torque instruction Tm* (the generation method illustrates below) that is 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, by torque instruction Tm*, the secondary magnetic flux instruction Φ 2* that will multiply each other from the torque elementary instruction Tm0* of the control part (not shown) of outside input and damping operational ton DAMPCN (aftermentioned), the circuit constant of alternating current motor 6, according to following formula (1) and (2) calculating d axle (excitation component) current-order Id*, q axle (torque component) current-order Iq*.

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

ωs*＝(Iq*/Id*)·(R2/L2) ......(3)

The output of the speed detector 7 of the slip angular frequency instruction ω s* that will calculate by this formula (3), the axle head that is installed in alternating current motor 6 is the result of anglec of rotation frequencies omega r through adder 20 additions, inverter angular frequency as inverter 4 outputs, the inverter angular frequency through the result of the integrator 21 integrations phase angle θ as coordinate transform, is inputed to dq axle-three-phase coordinate converter 22, three-phase-dq axial coordinate converter 23.

In three-phase-dq axial coordinate converter 23, the detected U phase current of current detector 5a～5c Iu, V phase current Iv, W phase current Iw are transformed to d shaft current Id and q shaft current Iq on the dq coordinate of 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 is calculated the poor of q shaft current instruction Iq* and q shaft current Iq, the result is inputed to the q shaft current controller 12 of next stage.The value of 12 pairs of inputs of q shaft current controller is carried out proportional plus integral control, output q shaft voltage offset qe.

Subtracter 11 is calculated the poor of d shaft current instruction Id* and d shaft current Id, the result is inputed to the d shaft current controller 13 of next stage.The value of 13 pairs of inputs of d shaft current controller is carried out proportional integral and is amplified, 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 the following formula, s is a differential operator, and K1 is proportional gain, and K2 is a 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,, calculate d axle feed-forward voltage Ed*, q axle feed-forward voltage Eq* according to following formula (7), (8) by the circuit constant of d shaft current instruction Id*, q shaft current instruction Iq*, alternating current motor 6.

Wherein, in formula (7) and formula (8), σ is by σ=1-M ²/ (L1L2) definition the leakage inductance coefficient.In addition, L1 is a self-induction of motor, utilizes L1=M+l1 to calculate.L2 is the secondary self-induction, utilizes L2=M+l2 to calculate.(l1 is a leakage inductance, and l2 is a 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, with the result of q shaft voltage offset qe and q axle feed-forward voltage Eq* addition as q shaft voltage instruction Vq*, the result of d shaft voltage offset de and d axle feed-forward voltage Ed* addition as d shaft voltage instruction Vd*, is inputed to dq axle-three-phase coordinate converter 22 respectively.

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)

At last, utilize dq axle-three-phase coordinate converter 22, generate voltage in three phases instruction Vu*, Vv*, Vw*, control inverter 2 by q shaft voltage instruction Vq* and d shaft voltage instruction Vd*.

By like this, vector control portion 6 implements the additional vector control that Current Feedback Control is arranged, so that the electric current of actual alternating current motor 6, be q shaft current Iq, d shaft current Id Id* is consistent with q shaft current instruction Iq*, the instruction of d shaft current of being 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, the vector control with known is identical basically owing to this control action, and therefore detailed action specification is omitted.

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

Before specifying damping control part 40 shown in Figure 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 the embodiment of the present invention 1 at the 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 that is connected with DC power supply 1.Fig. 2 is the performance of simplifying system shown in Figure 1.

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

In addition, change is arranged, the output of alternating current motor 6 is kept necessarily, promptly have the structure that the change that is controlled as for condenser voltage Efc has the characteristic that keeps permanent power even inverter 4 has the condenser voltage of being controlled as Efc.Even just be controlled as the Efc change, the input power Pinv of inverter 4 can not change yet.

In the system of the Fig. 2 that constitutes like this, from DC power supply 1 unilateral observation to inverter 4 have negative resistance property.

Negative resistance property is meant that then the input current Idc of inverter reduces if condenser voltage Efc rises; If condenser voltage Efc increases, the characteristic that the input current Idc of inverter reduces changes opposite with the relation property of change in voltage with the electric current of common resistance (positive resistance).In addition, as general knowledge, known common resistance (positive resistance) electric current when voltage rises increases, and electric current reduced when voltage reduced.

As mentioned above, the direct current portion of system shown in Figure 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, and the input current Idc of inverter increases, so become the action that promotes that condenser voltage Efc reduces.Therefore, the change 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 more than is qualitative explanation.

Next, obtain the system transter of Fig. 2, it is estimated, quantitatively illustrate with phenomenon to above explanation.

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

As mentioned above, inverter 4 Be Controlled get it and are output as necessarily.At this moment, 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 non-linear, therefore need carry out linearisation.If establishing the operating point of this moment is Efc0, Idc0, following formula (12) is set up in its vicinity.

[several 3]

$\mathrm{Idc}=-\frac{\mathrm{Pinv}\&CenterDot;(\mathrm{Efc}-\mathrm{Efc}0)}{{\mathrm{Efc}0}^2}+\mathrm{<figure-callout\; id="0"\; label="Idc"\; filenames="HSA00000567656200041.png"\; state="\{\{state\}\}">Idc</figure-callout>}0......\left(12\right)$

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

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

[several 4]

$G\left(s\right)=\frac{\frac{1}{C\&CenterDot;L}}{s^2+(\frac{R}{L}-\frac{\mathrm{Pinv}}{C\&CenterDot;{\mathrm{<figure-callout\; id="0"\; label="Efc"\; filenames="HSA00000567656200041.png"\; state="\{\{state\}\}">Efc</figure-callout>}0}^2})\&CenterDot;s-\frac{1}{C\&CenterDot;L}(\frac{R\&CenterDot;\mathrm{<figure-callout\; id="0"\; label="Pinv\; Efc"\; filenames="HSA00000567656200041.png"\; state="\{\{state\}\}">Pinv</figure-callout>}}{{\mathrm{Efc}}^{}}-1)}......\left(13\right)$

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

[several 5]

$s^2+(\frac{R}{L}-\frac{\mathrm{Pinv}}{C\&CenterDot;{\mathrm{<figure-callout\; id="0"\; label="Efc"\; filenames="HSA00000567656200041.png"\; state="\{\{state\}\}">Efc</figure-callout>}0}^2})\&CenterDot;s-\frac{1}{C\&CenterDot;L}(\frac{R\&CenterDot;\mathrm{<figure-callout\; id="0"\; label="Pinv\; Efc"\; filenames="HSA00000567656200041.png"\; state="\{\{state\}\}">Pinv</figure-callout>}}{{\mathrm{Efc}}^{}}-1)=0......\left(14\right)$

If establishing separating of following formula is α, β, because the both need be 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 separating with the relation of coefficient.

[several 6]

$\mathrm{\&alpha;}+\mathrm{\&beta;}=-(\frac{R}{L}-\frac{\mathrm{Pinv}}{C\&CenterDot;{\mathrm{<figure-callout\; id="0"\; label="Efc"\; filenames="HSA00000567656200041.png"\; state="\{\{state\}\}">Efc</figure-callout>}0}^2})<0......\left(15\right)$

$\mathrm{\&alpha;}\&CenterDot;\mathrm{\&beta;}=-\frac{1}{C\&CenterDot;L}(\frac{R\&CenterDot;\mathrm{<figure-callout\; id="0"\; label="Pinv\; Efc"\; filenames="HSA00000567656200041.png"\; state="\{\{state\}\}">Pinv</figure-callout>}}{{\mathrm{Efc}}^{}}-1)>0......\left(16\right)$

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

[several 7]

$R>\frac{L}{C}\&CenterDot;\frac{\mathrm{<figure-callout\; id="0"\; label="Pinv\; Efc"\; filenames="HSA00000567656200041.png"\; state="\{\{state\}\}">Pinv</figure-callout>}}{{\mathrm{Efc}}^{}}......\left(17\right)$

As seen from formula (17), L is more little, and C is big more, and Pinv is more little, and EfcO is big more, makes the required R of system stabilityization more little.

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

Yet the resistive component that exists in DC side is the small value about tens m Ω usually, is difficult to satisfy formula (17), and it is unstable that system becomes, and the LC filter circuit can produce vibration.

That is to say, in circuit shown in Figure 2, only however additional satisfy the resistance of formula (17) or can't realize controlling stable, condenser voltage Efc will vibrate and disperse.

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

Describedly illustrate quantitatively that similarly load is the situation of resistance (common positive resistance) load with top below.

Fig. 4 is illustrated in the figure that connects the circuit of the load that is made of resistance 60 on the LC filter that is connected with DC power supply 1.Comparing with circuit shown in Figure 2, is the circuit that inverter 4 and alternating current motor 6 are replaced by resistance 60.In addition, the resistance value of establishing resistance 60 is R0.

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

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

[several 8]

$\mathrm{Gp}\left(s\right)=\frac{\frac{1}{L\&CenterDot;C}}{s^2+(\frac{1}{C\&CenterDot;\mathrm{<figure-callout\; id="0"\; label="R"\; filenames="HSA00000567656200041.png"\; state="\{\{state\}\}">R</figure-callout>}0}+\frac{R}{L})\&CenterDot;s+\frac{1}{C\&CenterDot;L}\&CenterDot;(\frac{\mathrm{<figure-callout\; id="0"\; label="R\; R"\; filenames="HSA00000567656200041.png"\; state="\{\{state\}\}">R</figure-callout>}}{R}+1)}......\left(18\right)$

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

[several 9]

$s^2+(\frac{1}{C\&CenterDot;\mathrm{<figure-callout\; id="0"\; label="R"\; filenames="HSA00000567656200041.png"\; state="\{\{state\}\}">R</figure-callout>}0}+\frac{R}{L})\&CenterDot;s+\frac{1}{C\&CenterDot;L}\&CenterDot;(\frac{\mathrm{<figure-callout\; id="0"\; label="R\; R"\; filenames="HSA00000567656200041.png"\; state="\{\{state\}\}">R</figure-callout>}}{R}+1)=0......\left(19\right)$

Because separating all to satisfy, R＞0, all of the characteristic equation shown in the formula (19) is negative condition.Putting load as can be known from this is all-the-time stable when being made of resistance 60.

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

The following describes shown in Figure 4ly, in the output of LC filter, connect the characteristic of the circuit of resistance 60.

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

PR＝Efc·Idc......(20)

Condenser voltage Efc change, when becoming originally n times, the electric current I dc that flows through at resistance 60 becomes n doubly too, and therefore the power P Rn on the resistance 60 this moment is shown in the following formula (21).

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

I.e. square being directly proportional of the variation ratio of power P Rn on the resistance 60 and condenser voltage Efc as can be known.

From this point as can be known, the relation of formula (21) is set up, inverter 4 is moved as having positive resistance characteristic for the change of condenser voltage Efc by control inverter 4.

Yet the output of alternating current motor 6 can be expressed by the speed FM * output torque Tm of alternating current motor 6, and when 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 change of condenser voltage Efc, the power P invn when condenser voltage Efc increases to n times is the same with formula (21), as long as satisfy 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 the values with 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 handled is 10Hz～20Hz, is scaled the cycle, and the time is 50ms～100ms.From as can be known above, the cycle of oscillation of LC filter circuit, the velocity variations with respect to motor vehicle can be considered the very short time, and therefore on the basis of the structure of considering damping control part 40, the speed FM that can suppose alternating current motor 6 is for certain.

So, when condenser voltage Efc increases to n times, be n if control the torque Tm that makes alternating current motor 6 ²Doubly, can make square variation pro rata of the variation ratio of inverter input power Pinv and condenser voltage Efc.

Promptly adopt with the change ratio of condenser voltage Efc square value and torque instruction Tm* multiply each other to constitute and get final product.

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

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

Fig. 6 is the figure of relation of 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 filterings, unwanted low frequency component, calculate near the oscillating component Efca of resonance frequency that only extracts the LC filter circuit.For example, shown in Fig. 6 (a), condenser voltage Efc with 1500V be the center when the range oscillation of 1650V～1350V, Efca become as Fig. 6 (b) be shown in+150V～-signal of the scope of 150V and the oscillating component same-phase of condenser voltage Efc ground change.

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

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

The effect of HPF41, LPF43 is described herein.

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

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

On the oscillating component Efca that calculates as mentioned above, add DC component Efcd with adder 44, with its condenser voltage Efcad (Fig. 6 (c)) after as filter.

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

Then, when alternating current motor 6 electronic runnings, the Efcfp former state is inputed to square calculator 48.

In addition, when alternating current motor 6 regeneration operatings, utilize switch 47 to select with subtracter 46 to input to square calculator 48 from the 2 regeneration operating reverse signal Efcfn that deduct the change ratio Efcfp of condenser voltage Efc.This is because when alternating current motor 6 regeneration operatings, and the direction of power is opposite during with alternating current motor 6 electronic runnings, if condenser voltage Efc increase, then need be in the operation of the direction that regenerating power is reduced; If condenser voltage Efc reduces, need be in the operation of the direction that regenerating power is increased, regeneration operating is a signal (Fig. 6 (d)) with the phasing back of the change ratio Efcfp of condenser voltage Efc with reverse signal Efcfn.

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

In amplitude limiter 49, as required the upper limit, lower limit are arbitrary value after, to vector control portion 30 output as damping operational ton DAMPCN (Fig. 6 (e)).In amplitude limiter 49, for example be set to wish to limit and follow damping to control the situation of the transition variation of the torque Tm of alternating current motor 6.

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

Utilize the torque instruction Tm* that generates like this to carry out vector control, make inverter 4 actions with this, make inverter 4 be shown as positive resistance characteristic for the change 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 figure as a result of vector control apparatus of the alternating current motor of expression embodiment of the present invention 1.

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

As shown in Figure 7, under the situation (waveform on the right side of Fig. 7) of not implementing damping control of the present invention, condenser voltage Efc produces bigger vibration when every grade of the voltage Es of DC power supply 1 changes, but under the situation (waveform in the left side of Fig. 7) of having implemented damping control of the present invention, although there is the one-level of the voltage Es of direct current 1 to change as can be 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,, calculate best damping operational ton DAMPCN automatically, can constitute the damping control part that does not need the setting itself that gains according to embodiment of the present invention 1.And, owing to when calculating damping operational ton DAMPCN, do not use the constant of alternating current motor 6, so even 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 example as the situation of alternating current motor 6, but, also can use the structure of damping control part of above explanation and the computational methods of damping operational ton for the vector control portion under the situation of using this motor or other alternating current motors.

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

In the present embodiment, the change ratio n according to condenser voltage uses DANPCN=n when electronic running ²Calculate damping operational ton DAMPCN, when regeneration, use DAMPCN=(2-n) ²Calculate damping operational ton DAMPCN.The ratio that also can establish the fluctuation component of condenser voltage and DC component be Δ n (=n-1), according to greater than 0.5 gain K, when electronic running with DAMPCN=(1+K* Δ n) ²Calculate, when regeneration, calculate with DAMPCN=1.

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

In addition, K is big more, and then the effect of damping is big more, but the change of torque can increase when the condenser voltage drastic change.

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

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

In addition, the structure shown in the above-mentioned execution mode 1 is an example of content of the present invention, also can with other known technical combinations, in the scope that does not break away from main points of the present invention, certainly omit, change part etc. and constitute.

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 various association areas such as automobile, elevator, electric power system.

Claims (3)

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

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

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

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

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

Described damping operational ton is when the electronic running of described alternating current motor, and described condenser voltage flows through described inverter when increasing electric current increases, and described condenser voltage flows through described inverter when reducing electric current reduces.

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

Described damping operational ton is when the regeneration operating of described alternating current motor, and described condenser voltage increase then regenerating power reduces, and described condenser voltage reduces then regenerating power increase.

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