Embodiment
Below, the embodiment of the control device of alternating current motor of the present invention is described referring to figs. 1 through Figure 15.And, in following embodiment, use permanent magnet synchronous motor (below, abbreviate the PM motor as) to illustrate as motor, but can realize too for other synchronous motor (for example, coil form synchronous motor, reluctance motor etc.).
[embodiment 1]
Fig. 1 is the block diagram that the system of example controller for ac motor embodiment 1 of the present invention constitutes.The control device of present embodiment 1 is by forming with the lower part: the instruction 100 by host control device gives rotary speed instruction ω to motor
r *Rotary speed instruction generator 1; The interchange of calculating motor applies voltage, is transformed to the controller 2 of pulse width modulating signal (pwm signal) output; Converter (inverter) 3 by this pwm signal driving; Converter 3 is provided the transducer (converter) 4 of electric power; PM motor 5 as controlling object; Compressor 6 as the load of PM motor; Detect the current detector 7 that transducer 4 offers the electric current I 0 of converter 3.
Controller 2 is by forming with the lower part: according to by current detector 7 detected electric current I 0, reproduce the three-phase alternating current I that flows through on the PM motor 5 in controller inside by calculating
u, I
v, I
wElectric current reconstructor 8; Reproduced three-phase alternating current I
Uc, I
Vc, I
WcUse phase angle θ
Dc(in the position of the magnet magnetic flux of the PM motor of the inner supposition of controller) coordinate transform is d, the q composition I on each
Dc, I
QcDq coordinate converter 9; Electric current composition on the q axle is instructed I
q *I
q *Generator 10; Equally, the electric current composition on the d axle is instructed I
d *I
d *Generator 11; According to I
d *, I
q *And electric angle frequency instruction ω
1 *Calculating voltage instruction V
Dc *, V
Qc *Voltage instruction calculator 12; V
Dc *, V
Qc *Be transformed to three-phase alternating voltage instruction v
u *, v
v *, v
w *Dq inverse transformer 13; According to the three-phase alternating voltage instruction, produce the pwm pulse generator 14 of the pulse width modulating signal (pwm signal) that is used to make converter 3 switch motions; Infer and calculate the magnet magnetic flux position θ that is equivalent to PM motor 5
dWith position θ in controller 2 inner supposition
DcThe Δ θ estimator 15 of Δ θ of angle (axis error) of error; Carry out the adder-subtractor 16 of add operation and subtraction; To axis error presumed value θ
DcThe zero command generator 17 that instructs; For Δ θ being controlled at zero, at electric angle frequency instruction ω
I *The last proportional compensation device 18 that increases compensation; The number of poles P that uses the PM motor is rotary speed instruction ω
r *Be transformed to the electric angle frequency instruction ω of motor
1 *Conversion gain 19; Integration electric angle frequency is calculated magnet magnetic flux position θ
DcIntegrator 20; According to axis error presumed value Δ θ
Dc, infer the Δ T of computing cycle perturbing torque composition
mΔ T
mEstimator 21 (periodic perturbation estimator); According to Δ T
mPresumed value Δ T
Mc, at q shaft current instruction I
q *The torque controller (ATR) 22 of last increase revisal.
The diode bridge 42 that the transducer 4 that converter 3 is provided electric power is exchanged by AC power 41, rectification, the smmothing capacitor 43 that suppresses to be included in the ripple component in the direct voltage constitute.
Below, the operating principle of present embodiment 1 is described with Fig. 1.Conversion gain 19 is according to the rotate instruction ω from rotary speed instruction generator 1
r *, the electric angle frequencies omega of calculating PM motor
1 *Output.And then with integrator 20 integration ω
1 *, calculate and exchange phase theta
DcIn electric current reconstructor 8,, open method in the flat 8-19263 communique etc. with being recorded in the spy, by calculating the three-phase alternating current that reproduces the PM motor according to detected source current I0 in current detector 7.Below, in dq coordinate converter 9, reproduced alternating current I
Uc, I
Vc, I
WcUse θ
DcBe transformed to angular frequency
1 *Electric current composition I on the rotatable coordinate axis (dq axle) of rotation
Dc, I
QcI
QcAt I
q *Processed in the generator 10, become the current-order I on the q axle
q *In addition, I
d *The current-order I that generator 11 takes place on the d axle
d *(in the PM of non-prominent polar form rotor motor, common I
d *=0).In voltage instruction calculator 12, according to these instructions (I
d *, I
q *) and angular frequency instruction ω
1 *, calculate the PM motor applied voltage V
Dc *, V
Qc *V
Dc *, V
Qc *Be transformed to of ac once more with dq inverse transformer 13, and then in pwm pulse generator 14, be transformed to pulse width modulating signal, send to converter 3.For these elemental motion, with open the method for recording and narrating on the 2002-272194 communique the spy the same.
In Δ θ estimator 15, carry out the magnet magnetic flux position θ in the PM motor
dWith the position θ in the controller
DcError delta θ infer calculating.Δ θ defines with the polar plot of Fig. 2 example.The position of the magnet magnetic flux Φ of the reality of PM motor interior is set to the d axle, is set to the q axle with the axle of its quadrature.Relative therewith, the dq axle of supposing in controller is defined as dc-qc, both deviations are equivalent to axis error Δ θ.
If ask Δ θ, then, can make the d-q axle consistent with the dc-qc axle by revising it, can realize the no transducer control of PM motor.Δ θ infers calculated example as shown in Figure 3, can be at I
q *And I
QcDifference on multiply by proportional gain K0, be arranged to the presumed value Δ θ of Δ θ
DcI
QcBecause because load change etc., at θ
dAnd θ
DcSo last generation deviation and changing is from I
QcChange in can infer Δ θ on the contrary.But when when Fig. 3 constitutes, it is difficult asking Δ θ accurately.In order to improve precision, for example as long as the formula of opening in the 2002-272194 communique according to the spy (3) waits calculating.
According to the axis error presumed value Δ θ that calculates with Δ θ estimator 15
DcCarry out FEEDBACK CONTROL and make that it is zero.Ask the instruction (zero) and the Δ θ of zero command generator 17 with adder-subtractor 16
DcPoor, via proportional compensation device 18 in angular frequency
1 *On apply compensation.Shown in the polar plot of Fig. 2, when Δ θ is timing, the dc-qc axle is because also more leading than d-q axle, so by reducing ω
1 *, can reduce Δ θ, on the contrary, as Δ θ when being negative, by improving ω
1 *, make the d-q axle consistent with the dc-qc axle.By such control, do not use the position transducer of M motor magnetic pole axle, just can make the phase angle θ of controller inside
DcWith the magnet magnetic flux position θ in the PM motor of reality
dUnanimity can realize position Sensorless Control.
Below, describe Δ T in detail as characteristic of the present invention
mEstimator 21 (periodic perturbation estimator), torque controller 22.At first principle that takes place with the torque of Fig. 4 and Fig. 5 simple declaration PM motor and the relation of axis error Δ θ.
Fig. 4 represents to arrive the block diagram of the principle of axis error Δ θ generation from being applied in the voltage on the PM motor.In each piece of figure, R is the coil resistance of PM motor, and L is the inductance of PM motor, and P is the number of poles of PM motor, K
eBe the generating constant (magnet magnetic flux) of PM motor, J is the inertia of the total of PM motor and load device, and s is the symbol of differentiating that uses in Laplace transform.
As shown in Figure 4, q shaft current Iq applies voltage V by being applied on the PM motor
q, and the relation of electric constant R, the L of voltage disturbance VD, motor takes place.I
qBe the composition with magnet magnetic flux (d axle) quadrature of PM motor, by multiply by the generating constant K
e, become motor torque T
mThe rotary speed ω of PM motor
rBe integrating motor torque T
mWith load torque T
LThe value of difference.At this, load torque T
LKind and purposes according to load device have various characteristics.At ω
rOn multiply by number of pole-pairs (P/2), obtain the electric angle frequencies omega of motor
1, this integrated value becomes the position θ of PM motor
dPhase theta in θ conduct of axis error Δ and the controller
DcDifference obtain.
At this, consider at voltage disturbance VD, perhaps load torque T
LIn comprise periodic composition.
As periodic voltage disturbance VD, for example inhomogeneous at the magnet magnetic flux of PM motor, when magnetization was discrete, perhaps coil was alternate when discrete, equivalently as periodic voltage disturbance influence.Perhaps, because of the brachium pontis short circuit in the converter prevent during the disturbance that causes of the influence of (lag time) etc., also 6 overtones bands as the driving frequency of converter take place.
In addition, as the load cycling torque disturbance, for example, consider to have the load of the reciprocating compressor of use in freezer and air-conditioning etc. and single rotary compressor etc.When reciprocating compressor, as one-period, load is fierce to be changed motor rotation 1 circle.
In order to suppress vibration and noise controlledly, needing only as above-mentioned periodic cogging is to constitute control system zero.Countermeasure in invention in the past is that with some device detection rotary speed information, control applies voltage and makes that its rotary pulse is zero.In the compressor of air-conditioning etc., because directly obtain the velocity information difficulty,, obtain the information of one of 60 degree with electric angle so detect the change of the neutral point current potential of motor, infer computational speed.
But, in the manner, can only obtain 6 information to the electric angle cycle, be inadequate as velocity information.In this state, in influence that 60 degree postpone and speed accuracy of detection, have problems.The perhaps pulsation that produces for the distortion by the induced voltage of motor is because be the cycle (mainly be 1/6 cycle) also shorter than the electric angle cycle, so suppress difficulty.
In addition, also consider to use control theory to construct load disturbance observer etc., infer the method for calculating pulsating torque, but in this case, the response frequency of observer self becomes problem.When the frequency of pulsating torque was high, corresponding therewith, the setting response of observer also needed to improve.The frequency content of pulsating torque is high more, requires observer to have high more response, and its result needs high-speed computation to handle.Therefore, as the inhibition method of before this periodic perturbation, general vibration suppression in low-speed region can realize, and the inhibition difficulty during high speed rotating.
As an example, try to investigate the situation of using universal microcomputer to constitute observer.When the observer response time was set to 1ms (1, the 150Hz of 000rad/s → more), the pulsating torque that can detect was about 30Hz.If it is arranged to the motor of 4 utmost points, then be 900[r/min].When being compressor, because maximum speed is 3,000[r/min] more than, so can not be applicable to below the speed about 30%.
In the present invention, be conceived to the block diagram of Fig. 4, proposed from axis error Δ θ, to infer torque pulsation composition Δ T
mMethod.Axis error Δ θ can calculate because of instantaneous value, so can not be subjected to the influence of operating delay to carry out the high-precision calculating of inferring.In addition, have the frequency content high (for example, 6 times vibration component) and also can detect this feature relative driving frequency.Its result compares with periodic perturbation inhibition method in the past, can infer calculating significantly in high-speed region.
When such periodic perturbation takes place, motor torque T
mWith load torque T
LDifference become periodic cogging, become the vibration and the reason of noise.In order to suppress this vibration and noise, for example need to take to surround the countermeasure of device integral body etc. with sound-absorbing material, the problem that device maximizes and cost improves appears.
In order to suppress vibration and noise controlledly, needing only as above-mentioned periodic cogging is to constitute control system zero.Countermeasure in invention in the past is that with some device detection rotary speed information, control applies voltage and makes that its rotary pulse is zero.But, in the compressor of air-conditioning etc.,, be difficult, in addition so obtain velocity information simply because the motor compressor inside of packing into, even obtain, also can only considerably obtain the information of one of 60 degree at most with electric angle.Therefore, high precision int difficulty.
In the present invention, be conceived to the block diagram of Fig. 4, proposed from axis error Δ θ, to infer torque pulsation composition Δ T
mMethod.Axis error Δ θ can calculate because of instantaneous value, so can carry out the calculating of inferring of high-speed, high precision.In addition, have the frequency content high (for example, 6 times vibration component) and also can detect this feature relative driving frequency.
Fig. 5 is example load torque T respectively
LComprise with angular frequency
dTorque pulsation composition (Δ T during according to the composition of sine wave oscillations
m), rotating speed change (Δ ω
r), axis error (Δ θ).If consideration lower state, then T
mAnd T
LThe mean value unanimity, Δ T
mIt is vibration component (Fig. 5 (b)).Be included in the vibration component Δ ω in passing on
rBe this Δ of integration T
mComposition, with Δ T
mCompare, for phase delay 90 the degree waveforms.The size self of vibration depends on inertia J and changes, but can think that also phase place roughly postpones 90 degree.Axis error Δ θ is because further integration Δ ω
r, make opposite in sign (in defining relation shown in Figure 2, making opposite in sign), so leading 90 degree of phase place (after in integration, postponing 90 degree, because sign-inverted, so leading 90 degree).That is Δ T,
mVariance components in Δ θ as the observation of synchronous vibrational waveform.If derive this relation then as follows from the square frame line chart.
Fig. 6 (a) expression is from Δ T
mBlock diagram to Δ θ.By this block diagram of inverse transformation, can in the hope of from Δ θ to Δ T
mTransfer function, shown in same figure (c).
If ask Δ T according to Fig. 6 (c)
m, then from Δ θ
DcIn (presumed value of Δ θ), can directly infer the ripple component of torque.But, two stages of differentiation Δ θ
DcImpossible in now.Δ θ
DcOriginally be presumed value,,, also have the restriction of execution cycle in addition so use differential will increase estimation error because comprise the disturbance etc. of detected value mostly.
Thereby, pay close attention to " the disturbance composition is a periodic function " this point, s=j ω
dBring Fig. 6 (c) into.So shown in Fig. 6 (d), Δ θ is exaggerated the result of constant times, can be estimated as Δ T
m(b) among its result and Fig. 5 and the relationship consistency of waveform (d).
The formation of specializing Fig. 6 (d) is Δ T shown in Figure 7
mEstimator 21 (periodic perturbation pushes away 3 and decides device).Δ T
mEstimator 21 (periodic perturbation) is by 3 Δ θ
Dc Enlarge 2J/P proportional gain 211 and 2 multipliers 212 doubly and form, implement the computing of Fig. 6 (d).
According to Fig. 7, can be from Δ θ
DcIn infer and be included in Δ T
mIn angular velocity omega
dThe periodic perturbation composition.
Below, illustrate and suppress this Δ T
mCommentaries on classics 3 square controllers 22 (Fig. 8).
As 2 conditions below the conditional request of torque controller necessity.
(1) to periodic perturbation followability height
(2) the composition medium sensitivity beyond periodic perturbation low 3 (1) is in order to suppress the most important condition of periodic perturbation.(2) be when transition etc., to have taken place to be used to prevent the whole necessary condition of torque controller influence control under the situation of Δ θ of direct current.As mentioned above, this compensator prerequisite is " periodic perturbation is arranged ", and equivalence transformation shown in Figure 6 can not be applicable to direct current disturbance etc.Thereby, in the composition beyond the periodic perturbation, need desensitization.
The torque controller of Fig. 8 example is by to Δ T
mPresumed value Δ T
McGive the zero command generator 17 of zero instruction; In angular frequency
dIn have the sinusoidal wave transfer function 221 of peak value; Torque ride gain 222 constitutes.At this moment, make the angular frequency of sinusoidal wave transfer function 221
dConsistent with the variation frequency of periodic perturbation torque.When being compressor etc., the variable cycle of frequency disturbance is because be the frequency consistent with driving frequency, so make ω easily
dConsistent with ripple frequency.In addition, even for the periodic voltage disturbance, because almost be the integral multiple of driving frequency, so this ω
dThe setting ratio be easier to.
In addition, this torque controller satisfies above-mentioned condition (1), (2) both sides.Sinusoidal wave transfer function is in the angle frequencies omega
dMiddle gain can be only being included in Δ T for infinitely great
McIn ω
dThe key element deviation of composition is set to zero, does not have sensitivity in addition frequency content.The spy that in detail for example is illustrated in for sinusoidal wave transfer function opens in flat 7-20906 communique etc.
By using the torque controller 22 of Fig. 8, angular frequency
dThe signal I of sine wave
QSINAdd at I
q *On, can torque pulsation inhibited composition Δ T
m
More than, be that example has illustrated embodiments of the invention 1 with the periodic perturbation load, but also can tackle equally for periodic voltage disturbance.In addition, as electric current detecting method, use the method for from the current value I 0 of transducer 4, reproducing motor current, but also can directly detect each phase current with Hall CT and shunt resistance.
[embodiment 2]
Below, with Fig. 9 embodiments of the invention 2 are described.
In embodiment 1, to torque pulsation vibration frequency ω
d, import gain and be infinitely-great sinusoidal wave transfer function.Its result is included in the ω in the torque pulsation
dComposition is removed, and the distortion of the drive current of the PM motor in generation increases.Because instantaneous following in load torque change, so, can not avoid the big phenomenon of transient current change, owing to this reason, produce the efficiency degradation of PM motor, perhaps because the overcurrent trip that peak current causes etc. unusual.Thereby, we can say to such an extent that relax the reduction effect of vibration noise on the whole, prevent practicality aspect the compromise point of current distortion in adjustment on the contrary.
Embodiment 2 is to the additional function of adjusting the inhibition ability of the inhibition effect of periodic perturbation.
The formation of torque controller 22B in Fig. 9 example present embodiment 2.Use this torque controller 22 to realize embodiment 2 by the torque controller 22 that replaces Fig. 1.
Among the torque controller 22B in Fig. 9, constitute by sinusoidal wave transfer function 221B, ride gain 222B with peak value inhibit feature, zero command generator 17, adder-subtractor 16.Sinusoidal wave transfer function 221B with peak value inhibit feature has the Tas item on denominator, according to the size of Ta, can change the peak value of function.
Its result can adjust ω
dThe Disturbance Rejection effect of composition can drive in the optimum of the distortion of noise and vibration and PM motor phase current.
Below, with Figure 10 embodiments of the invention 3 are described.
In embodiment 1,2, as torque controller, to the vibration frequency ω of torque pulsation
dImport the transfer function of gain maximum (being infinitely great) in embodiment 1.In these controllers on terminal with the size of the ride gain (ride gain 222, perhaps ride gain 222B) of deferent segment, determine the convergent response of ripple component.
But, the set point of these ride gains and actual response time concern complexity, make that distribution board (board) line chart is studied or obtain by analogue test, actual measurement.Therefore, in the adjustment operation, need to pay a lot of energy.
In embodiment 3, be provided for simplifying the torque control appliance of adjusting operation.
Figure 10 represents the formation example of the torque controller 22C in the present embodiment 3.Use this torque controller 22C can realize embodiment 3 by the torque controller 22 that replaces Fig. 1.
Among the torque controller 22C in Figure 10, by individual event-dq coordinate converter 223, time lag of first order filter 224, integral controller 225, dq-individual event inverse transformer 226, and integrator 20, adder 16, zero command generator 17 are formed.The below action of this torque controller of explanation 22C.
Δ T
mThe output Δ T of estimator
McIn individual event-dq coordinate converter 223, be decomposed into SIN composition and COS composition.And the transform of individual event-dq coordinate converter 223 is as follows.
[formula 1]
(formula 1)
According to (formula 1), if at Δ T
McIn comprise ω
dFrequency content, then according to its amount, Δ T
Ds, Δ T
QSMean value be the value of non-zero.This mean value respectively be included in Δ T
McIn the COS composition, and SIN composition unanimity.But, at Δ T
Ds, Δ T
QsIn, because comprise ω in a large number
d2 times of compositions, so in time lag of first order filter 224, need the deletion alternating component.Its result, Δ T
Ds, Δ T
QsBe included in Δ T
McIn ripple component, the COS composition, and SIN composition.Below, because each composition is set to zero, so give as " zero " signal that instructs the deviation of calculating and instruction in adder-subtractor 16 from zero command generator 17.According to these deviations, integral controller 225 carries out integral compensation, the pulsation Composition Control zero.At last, I
Ds, I
QsThe value contravariant be changed to the individual event signal, output I
QSINThis inverse transformation is calculated according to following formula.
[formula 2]
(formula 2)
Ripple component Δ T
McAfter using (formula 1) coordinate transform, because become DC quantity, so in integral controller 225, can remove deviation.That is, if this torque controller is from the outside, then with in angular frequency
dMiddle gain becomes infinitely-great elements of compensation equivalence.That is, have and the equal frequency characteristic of the torque controller 22 of embodiment 1.
When torque controller 22C, compare with the torque controller of Fig. 8 and Fig. 9, adjust the position at time lag of first order filter time constant T
ATRGain K with integral controller 225
IATR2 places.But, T
ATRBecause as long as to ω
dSelect abundant big time constant to get final product, so method of adjustment is difficult especially.In addition, K
IATRValue directly determine the response time that ripple component suppresses, the control response time is to K
IATRValue be linear.Its result can obtain gain setting and be easy to effect.
[embodiment 4]
Below, use Figure 11 that embodiments of the invention 4 are described.
In embodiment 3, for vibration frequency ω
d, provide gain to be infinitely-great torque controller.Be of equal value as action in this torque controller (Fig. 8) at embodiment 1.Therefore, the same problem that produces and in embodiment 2, record and narrate.That is, be included in ω in the torque pulsation
dComposition is removed, and the distortion of the drive current that produces the PM motor in generation increases, and the efficiency degradation of PM motor perhaps causes the unusual of overcurrent trip etc. because of peak current.
Thereby, the same with embodiment 2, propose angular frequency
dIn gain be set to limited method from infinity.
The formation of torque controller 22D in Figure 11 example embodiment 4.Use this torque controller 22D by the torque controller 22 that replaces Fig. 1, can realize embodiment 4.
Torque controller 22D in Figure 11 and the difference of the torque controller 22C among Figure 10 are that integral controller 225 is changed to incomplete integral controller 225D.Time constant Ti that the full integrator 225D that toos many or too much for use is interior and gain K
IATRSuppress peak value.Its result can adjust ω
dThe Disturbance Rejection effect of composition can drive in the optimum of the distortion of noise and vibration and PM motor phase current.
[embodiment 5]
Below, use Figure 12 that embodiments of the invention 5 are described.
In embodiment 1~4, narrated presumed value, estimated period torque pulsation composition, the method that is suppressed according to axis error Δ θ.Though main ripple component shows as I
QcWith the axis error presumed value, but to I
DcAlso influential.
Though the d shaft current does not give torque,, also on the d direction of principal axis, produce the electric current that causes because of pulsation because of the torque pulsation rotating shaft departs from.The example that utilizes it further to reduce torque pulsation is embodiment 5.
In Figure 12, the controller 2 among controller 2E and the embodiment 1 is roughly the same.Newly append the d shaft current controller I of the Current Control of carrying out d axle (dc axle)
DACR(22C).22C for example imports and the identical information of torque controller 22C shown in Figure 10 (gain K
IATRNeed to adjust), replace Δ T
McInput I
Dc, at I
d *On the output that adds.In voltage instruction calculator 12, I
d *Carry out the calculating of voltage instruction as new command value.
By appending I
DACR, can remove and be included in I
DcIn ripple component, its result can reduce the torque pulsation composition.
[embodiment 6]
Below, with Figure 13 embodiments of the invention 6 are described.
In Figure 13, part number 1,2,3,5,7,41,42,43 is identical with the part of same number among the embodiment 1 respectively.In the present embodiment, be controller 2, converter 3, current detector 7, diode bridge 42 integrated miniaturizations on power model.As rotary speed instruction generator 1, use outside microcomputer, by the instruction of communication transfer rate.Other by distribution AC power 41, smmothing capacitor 43, PM motor 5, can realize suppressing the periodically control device of the synchronous motor of torque pulsation on power model.
The objective of the invention is to reduce soundproof vibration-proof material, the miniaturization of implement device by reducing the noise and the vibration of system.In present embodiment 6,, has the further effect of the miniaturization of implement device integral body by modular controller and converter.
[embodiment 7]
Below, use Figure 14 that embodiments of the invention 7 are described.
In Figure 14, part number 2,3,6,7,42,43 respectively with at embodiment 1 (Fig. 1), and the part of same number is identical among the embodiment 6 (Figure 14).Present embodiment uses the probability module that is assembled with controller 2, converter 3, current detector 7, diode bridge 42 to constitute the off-premises station 30 of air-conditioning.In the compressor of air-conditioning etc., the PM motor of packing in the compressor inside of air-tight state, it is difficult detecting the rotating speed of PM motor and the position of magnetic flux etc.
But by assembling controller of the present invention, rotating speed and the position that can not detect the PM motor reduce vibration and the noise that compressor takes place.
Variation when Figure 15 represents to start compressor of air conditioner of the present invention and changes rotating speed, noise, and the figure of variation one example of current waveform.In Figure 15, pass on from being changed to low speed at a high speed, so overall noise descends because of handle.
After the rotation speed change of compressor, noise and vibration are left over, but interior noise descended by tens of seconds from the several seconds.At this moment, in the front and back that noise reduces, the distorted waveform of electric current changes.This is the rotation speed change owing to compressor, because the periodic perturbation occurrence condition changes, so produce transient.Even for this transient, because controller reacts gradually, noise is descended, so the waveform of electric current (distortion) changes.
When of the present invention, because calculate, can suppress periodic perturbation, so, also can observe this phenomenon when even rotating speed is high according to instantaneous axis error.When the highest frequency of the frequency of Driven Compressor is set to 100%,, can realize that also low noiseization hangs down vibrationization even in surpassing 30% scope of highest frequency.
In addition, shown in the current waveform of Figure 15, also can obtain same effect not only for the disturbance composition of the frequency also lower, and for the frequency content also higher than driving frequency than driving frequency.
And, as embodiment, with the air-conditioning example explanation, but other electric equipment, for example, when packing compressor and freezer etc., also can obtain same effect.
As mentioned above, if adopt the present invention, then do not use the rotating speed of detection synchronous motor and the transducer of rotating shaft position, can realize suppressing load device, perhaps the high-performance motor of the periodic disturbance of motor self generation drives.And, even under the situation of the transducer that the rotating speed that detects synchronous motor and rotating shaft position are arranged, also can realize equally.