JPS6343594A - Ac motor driving apparatus - Google Patents

Abstract

PURPOSE:To vary a large capacity Ac motor from low to high speed without pulsation of the torque by using a double converter, a phase advancing capacitor and a cycloconverter. CONSTITUTION:In a double converter CONV, the DC sides of double converter SSP, SSN connected in anti-parallel with one another are connected through a reactor Ld with a DC power source. A phase advancing capacitor CAP is connected to the AC side terminal of the converter CONV. The input side of a circulation current type cycloconverter CC is connected to the capacitor CAP, and the output side is connected to an AC motor M. The converter CONV is so controlled that the peak value of the voltage applied to the capacitor CAP becomes substantially constant. The converter CC is so controlled as to supply a variable frequency sine current to the motor M.

Description

[Detailed description of the invention] [Object of the invention] (Industrial application field) The present invention provides an AC
The AC electric power that drives the J-type is related to a drive device.

(Prior art) In general, AC motors include induction motors, kaimei motors,
There are reluctance morphs, etc. For example, a voltage source automatic inverter is a conventional device that receives power from a DC power source to drive these AC ff1iFII machines.

This voltage type self-excited inverter uses transistors and G'rO (
It consists of a self-extinguishing element such as a gate turn-off switch (gate turn-off switch), and can supply alternating current power with variable voltage and variable frequency to an alternating current motor.

In this case, by performing 11 pulse width modulations (PWM), the supply to the above 'ilf 1FII□'1
``There is evidence that the waveform of the discharge is approximated to a sine wave by controlling It and It to reduce torque pulsation.

(Problems to be Solved by the Invention) A conventional AC motor drive device using such a self-excited inverter requires a self-extinguishing element such as a transistor WGTO, which increases the cost of the device. It was difficult to protect the device from the oxidation, and there was a problem in terms of reliability.

Further, the switching frequency of a large capacity self-extinguishing element such as a GTO is limited to about 500 to 1,000111, and the modulation frequency of pulse width modulation control is limited to the above frequency range. Therefore, when the rotational speed of the AC motor is increased, torque pulsations occur due to current pulsations.

Thus, conventional AC motor drive devices using automatic inverters are suitable for small to medium sized devices, but have the problem of being difficult to apply to large capacity and high speed AC motors.

The present invention was made to solve the above problems, and
AC electric motors (1-drive performance) enable shifting from low to high speeds without torque pulsation compared to large-capacity AC motors, and significantly improve reliability. The purpose is to provide.

[11'4 of the invention] Means for solving the problems) According to the present invention, two converters connected in anti-parallel are connected on the first stream side to a DC type K via a reactor. 2
a double converter, a V-phase capacitor (connected between the AC side terminals of the double converter), a circulating current type cycloconverter whose input side is connected to the phase advancing capacitor, and whose output side is connected to the AC motor; The double converter is controlled so that the wave height of the voltage of the phase advance capacitor is substantially constant, and the lagging reactive power of the double converter and the cycloconverter described by +iFj is equal to the leading reactive power of the phase advance capacitor. Variable frequency ° current 1
) A diary thunder! The invention is characterized in that it includes a control means for controlling the cycloconverter so as to supply the cycloconverter to the JJ '43.

(Function) In the present invention, the control means controls the double converter so that the peak value of the voltage applied to the phase advance capacitor is substantially constant, and the variable frequency sine wave current is applied to the AC motor. A circulating current type cycloconverter is controlled so that the current is supplied.

At this time, the phase advance capacitor becomes a leading reactive power source for the double converter and the circulating current type quantity cycloconverter, and its frequency (several hundred 11z) is equal to the lagging reactive power generated by the double converter and the cycloconverter. It is determined so that the leading reactive power of the phase leading capacitor is equal to the leading reactive power. In other words, by providing a phase control reference signal for the double converter and the cycloconverter using an external sine wave oscillator, the cycloconverter is controlled so that the frequency and phase of the voltage of the phase advance capacitor match the frequency and phase of this oscillator. A circulating current of .

The phase advance capacitor voltage established in this way allows the double converter and the cycloconverter to perform power conversion with only natural commutation, and it is possible to provide a high-speed, large-capacity AC motor drive device.

(Real/One Color Example) FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

In the same figure, a DC reactor is connected to the DC power supply vd,
The DC side of the double converter C0NV is connected via the. This double converter C0NV is a positive group converter S
S l) and <11!1 converter SSN are connected in antiparallel, and a phase advance capacitor CA is connected between their AC side terminals.
I) (the capacitor between the terminals is represented as one 6) is connected.

In addition, a cycloconverter C is used as a phase advancing capacitor CAP.
The input side of C is connected, and the output side of this cycloconverter CC receives AC power! l1JJ Kai M /fi is connected. Here, cycloconverter CC is mainly converter S
The converter S-8S3 is composed of a converter S-8S3 and DC reactors L1 to L3, and each converter S81 to S83 is insulated from each other by a high frequency transformer TR.

In addition, in order to control the 2-ton converter C0NV, a current detector CTd detects the 11i current flowing here, and two voltage detectors detect the voltage applied to the phase advance capacitor CAP.
, a rectifier circuit D1 that rectifies the output of this voltage detector AP1] CAP outputs a DC current command value based on the voltage peak value V of the phase advance capacitor CAP output from this rectifier circuit. voltage control circuit AVR, this DC current command value I
A current control circuit ACR1 generates a control signal for the converter current 1IIJ based on the deviation between d and the current detection value I of the current detector CT, and based on the output of the external excavator oSC and the output of the current control circuit ACR. Te2 city converter C0N
A phase control circuit P H01 for controlling V is provided.

Further, in order to control the circulating current type cycloconverter CC, a rotational pulse generator PG detects the rotation speed of the AC electric motor IM, and current detectors CT, CT, detect each phase current of the AC electric motor IM.

CT, Speed control circuit 5PC1 that calculates the rotational speed detection value of the rotational pulse generator PG When these current command values CI- are detected, +I, I, IH are compared for each phase W
A current control circuit ACR2 that integrates or proportionally amplifies the partial I's component and outputs it, the output of this current control circuit A C+< , and the external oscillation Z
A phase control circuit 1''l-I C with the output of
2 is answered.

”-51 shows the general operation of this embodiment made by Mh as described below.
After that, I will explain the corrected operation.

First, the 2-small converter C0NV performs power conversion between the DC power supply vd and the phase advance capacitor +'jcAP,
When the DC current 1d is flowing in the direction of the arrow shown in the figure, the 1 unit positive group inverter SSP operates, and when the DC current 1d is flowing in the opposite direction to the arrow, the power is regenerated. The DC current rd is controlled so that the voltage applied to the phase advance CAP becomes approximately constant, and the DC current rd is controlled so that the voltage applied to the phase advance CAP becomes approximately constant.

Next, the cycloconverter CC is of a delta-connected circulating current type and is controlled wJ to supply variable voltage variable frequency three-phase AC power to the AC motor M using the phase advance capacitor CAP as a three-phase 711i source.

In addition, for phase control of the double converter C0NV and the cycloconverter CC, three-phase quasi-voltages e, e1. from the external excavator O8C are used. , e c signals are used, and the voltages V and Vb of the phase advancing capacitor CAP are used.

■ The frequency and phase of are the reference voltages e, el, ,
e.

a It will be controlled by the frequency and phase of

A detailed explanation of these operations will be given below.1 First, the voltages V and Vb of the phase advancing capacitor CAP.

The startup operation for establishing VC will be explained.

FIG. 2 shows the circuits of the positive group converter SSP and the phase advance capacitor CAP at startup, and the SSP is composed of one Noristor S to S6. Furthermore, the phase advance capacitor CAP is composed of C35, Cbo, and Coa.

Now, if an ignition pulse is applied to thyristors S4 and $2, the DC current I will be as follows: power supply Vd → reactor Ld → thyristor S4 → capacitor) J-C,b → reactor Ld →
Thyristor S4 → Capacitor tZCca → Capacitor C →
Thyristor S → bc of power supply Vd
2. Flows into the path. As a result, capacitor Cab is filled with DC distribution It V d, and capacitors Cbo and CCa
A voltage of =(d/2) is applied to.

Figure 3 shows thyristors S1 to S6 of the positive group converter SSP.
The ignition mode and the phase-advanced condenser that changes accordingly→
) The waveforms of the applied voltage vab of C and the phase voltage b2 are shown.

After the mode of FIG. 2, a firing pulse is applied to thyristor S3. Then, a reverse bias voltage is applied to the thyristor S2 by the voltage charged in the capacitor Cbo, and the thyristor 82 is turned off. In other words, at startup, the phase advance capacitor CAP plays the role of a commutating capacitor and the J0 thyristor S
4 and S3 are turned on, the phase advance capacitors Cab and Cb
The 11-ton pressure applied to c and Coa also changes.

The voltage Va-b applied to the phase advancing capacitor Cab is the third
J in the figure: Changes stepwise depending on the firing mode of the uni thyristor S-86. However, in reality, the voltage +V, -, and voltage are accelerating and are charged through the voltage, so the voltage gradually rises as shown by the broken line. If the time is 2δ, the fundamental wave component of va-b is delayed by δ. Also, the phase voltage ■ is the line voltage va
The phase is delayed by (π/6) radians with respect to −b.

As can be seen by comparing the ignition mode of thyristor S-86 and the above phase voltage Va, the phase control angle α at startup is α = π - δ (radian) ...... (1
). Since δ is not very large, approximately C and α are operated at 180°.

At this time, if the output voltage V of the converter SSP is taken as a positive value in the direction of the arrow in Fig. 2, then V=-V-cosα...
(2) p cap
p. However, k is a proportionality constant, and Vcap is the phase voltage peak value of the capacitor.

The inverted value -V of this output voltage (2) is balanced with the DC voltage pVd. However, if this continues, the phase advancing capacitor CAP will not be charged to a voltage higher than the DC voltage Vd.

Therefore, the firing phase angle α is slightly shifted in the direction of 90°. Then, the inverted value -■ of the output ゛i pressure ■ decreases, Vd>-V, and the DC current fd flows in the direction of the arrow. As a result, the energy P ・1-(12

/2) CV is accumulated in the phase advance capacitor and cap
Cap Ru. As a result, the voltage V increases and settles down to ■, ap -■. At this time, the current 1. is zero.

If you want to further increase vcap, the firing phase angle a,
is further shifted in the direction of 90', and the inverted value of the output voltage -■
. This can be achieved by reducing the At α, = 90', it becomes (ma-■, -〇, and theoretically (the city supply voltage d
is a very small value and the capacitor voltage V. 8. can be charged to a great value. However, in reality, since there is circuit loss, it is essential to supply power for that amount.

In this way, the voltage Vcap of the phase advancing capacitor CAP can be charged to an arbitrary value.

Next, the phase advance capacitor CAP established in this way
The voltages ■, b, vo are phase-based 911 circuit P in Figure 1)
-ICi, 3-phase base quasi-voltage given to PI-IC2 0
．． The fact that the frequencies and phases of eb and eo match is taxed.

Figure 4 shows the phase control reference voltages e, e, , e output from the external oscillator O8C in Figure 1 and the circulation a.
C Converter ss that constitutes the flow type cycloconverter CC
-5s3 ignition pulse mode is not shown.

1fl 1III 'gfJl quasi-voltage e, e, , eC
is expressed as the following equation.

e = E −5in(ω.−t)
−・・・・−(3)m e −E−sin(ω−t−27r/3)−(4)b
m c e =E-sin(ω・t+2π/3)=15)C
m Nicode, [is unit voltage peak value, ω. = 2πf lJ High frequency angular frequency, for example f. =50
Selected as 011z culm 1q.

Phase I7 voltages V, , Vb of the phase advancing capacitor CAP.

■ is the above standard (city pressure e, el), the frequency of e and C
a C Phase matching, converter SS1 to S83
Each output voltage of is as follows.

V,=k・y,, -cosα1 ・・・・・・(6
) v2-ni-vo, p-CO3α2 ・・・・・・(
7) V3=k-V, p-cosα3...
(8) At startup, the output voltage of each converter is V, V2゜■
are set to zero, so the control phase angles α1°α2 . α
is α=α2−α3=90′. Ralaro/νV +V2+v3=O, and the circulating current of the J inverter CC does not increase.

From this state, if the frequency of the capacitor: 'Ij; lT= becomes low, v', v, ' as shown by the broken line in FIG.

■Consider the case where o' occurs.

In this case, the firing phase angle of converter SS1 is from α to α
1', and the firing phase angle of S82 changes from α to α',
Further, the firing phase angle of S83 changes from α to α'. Therefore, v1→-V2+V3>0, which increases the circulating current of the cycloconverter CC. This circulating current becomes delayed reactive power on the input side of the cycloconverter CC as viewed from the phase advancing capacitor CAP side.

FIG. 5 shows an equivalent circuit for one phase on the input side of the cycloconverter CC, in which the cycloconverter CC and the double converter C0NV are replaced by a variable inductance Lcc that takes a delayed current. The resonant frequency f of this circuit is cap.

An increase in the circulating current of the cycloconverter CC results in an increase in the equivalent inductance. 0 is equivalent to decreasing, the above frequency f increases, and ■,'.

cap Vb', V' (7) frequency f is N quasi voltage ea.

CCap The frequency of e, , O [. approach.

Similarly, if you get angry, please call The current decreases and 'ccB becomes too large, and again f. a.

It settles down to -1.

If the phase of the phase leading voltage is delayed from the phase of the reference voltage, the cap becomes 1.
As in the case of c, the circulating current increases and the phase advancing capacitor CΔ
1) Advance the voltage phase. Conversely, the phase advance capacitor CA
l)' voltage (if the η phase is the reference voltage J: advance/υ, the current is c
ap c decreases and delays the voltage phase of ) lU phase capacitor CΔP. In this way, the voltages V, V of the phase advancing capacitor CΔP
, , the frequency and phase of Vo are based on *voltage e , c , e
The magnitude of the circulating current of the converter CC is automatically adjusted so as to match . Therefore, these condensation→no lightning pressures V,
Vb,0 is expressed as in the following equation.

V = V -5in (ω-t) -----
--(10)a cap c ■b””vcap・5in(ω・t−2π/3)・・
...(11) V = v -5in (ω-t+27r/3)
c cap c・・・・・・
(12) However, vcap is the phase voltage peak value.

Cross 21! The same operation occurs when the rotational speed of l-motor ~1 increases and each converter SS1 ~ SSo generates an output voltage. In other words, steady state (phase advance capacitor C
When the voltage phase of AI) matches the reference voltage, V4-■+V3=O is satisfied, and the circulating current of the microconverter CC does not increase or decrease.

If the circuit deviates from this state, the circulating current of CC is automatically adjusted so that the frequency and phase of the phase advancing capacitor CAP always match those of the standard voltage.

As described above, the voltages V, V, of the phase advancing capacitor CAP,
, Vo are established, but then the control of the double converter C0NV and the cycloconverter CC after these voltages are established IJJ! Explain the work.

Figure 6 shows the control section of the double converter C0NV in detail, so if it corresponds to the control circuit in Figure 1, the following J,
I'm going to growl.

First, the voltage control circuit ΔVR in FIG. 1 is the voltage setter VR, the comparator C, and the voltage control compensation circuit G in FIG. (s)
Consisting of

In addition, the next current control circuit A CR1 is the comparator C in FIG.
, current control 211 supplementary t3 circuit G1 (S), addition A +
), performance lTh1! [In the circuit, +1"4 is formed by inverting m1NV, hysteresis circuit IIs, mono multi-circuit MM, and logic circuit LC.

Furthermore, the phase control 1 [1 circuit P H01 in FIG.
The phase control circuit 211 shown in the figure is combined with the circuit P II I7 P HN and the switch circuit As ΔS2.

Here, the voltage of the phase advance capacitor CAP is set to L [detection volume P
Detected by T, l! The three-phase current 1 [rectified by the rectifier 1] is rectified by the rectifier 1. As a result, the voltage peak jIQ V cap of the phase advancing capacitor CA P is input to the comparator C1.

Also, the voltage command value ■ from the voltage setting device VR. ap is output, and the above detected value ■ is obtained by the comparator C1. 8. (compare.

The (1 difference ε.=Vcap~vcap) between these is input to the next voltage control 121I compensation circuit G (S), where it is integrated or proportionally amplified. This voltage control compensation circuit G (S
) is input to the comparator C2 as a direct current command 1a.

-10,000 DC current I by DC current transformer CT.

Detect and compare ``BC2 above''; [flow command value l
, the deviation εI=Id fd is calculated. The deviation ε
l is the following current 1. The control compensation circuit GI(s) integrates or proportionally amplifies the phase of the positive 8T converter SSP via the adder AD.
is input. In addition, 1 stroke inverter INV of adder q device AD
through the phase control circuit P l- of the negative group converter SSN
It is input to IN.

The adder AD subtracts the DC voltage detection value vd multiplied by a constant by the operational amplifier KV from the output signal of the current control compensation circuit G, (s) and outputs the result.

However, Tadashi/! Phase control input voltages v , v of the Y and negative group converters. p (IN is as follows.

VaP=G, (S>・ε, −K −Vd −・・(
13) ■ v a N -G (S)”
ε 10 K・V dl
1v...(14) On the other hand, the voltage control oil tp1 circuit G, (s) output switch ld is connected to "1"' through the hysteresis circuit 1-IS.
or O'' digital signal 51g1.

This j<: >3 s i (71 generates a pulse signal 51g2 through one multi-circuit I'8 to IM, and the other one is input to C as it is as a logic circuit.

FIG. 7 shows the Quimshawer 1- for explaining its operation, and the DC current command 1. Indicates each signal 5191 to 51g4 when (from 1 to positive and from positive/) to negative.

First, the DC current command value 51g1 (j changes from negative to i[and becomes the output of the cis circuit +]S becomes "1°").

In addition, when the DC current command value rd changes from positive to negative,
When 1d≦−△1, “hysteresis circuit H”
The output signal of S becomes O''.

The next monomulti circuit M~1 is a hysteresis circuit! -IS
The pulse width is 6 at the rise and fall of the output signal 5io1.
A second pulse signal 51g2 is generated.

The output signals 51g3 and 51g4 of the logic circuit LC are generated by the above-mentioned signals 51g1 and 51g2.

In other words, 51g3 is created by taking the AND of 51g1 and sig2 (the inverted value of sig2), and 5
1g4 is 5iG1 (sigl) anti[fiff) tos
i g2 (s i Q2 (1) inversion 11m) f7)
J: is required for logical product.

The output signal 51 of the logic circuit LC obtained in this way
g3, 51g4 are switch circuits AS and σA, respectively.
Open and close S2. That is, when Si93 is "1", switch AS1 is turned on and gives a gate signal to positive group converter SSP. Also, when 51g4 is "1", switch S2 is turned on and gate signal is applied to negative group converter SSN. give a signal.

Accordingly, the direct current command value ■ changes from negative to positive, and the converter SSN stops operating, and after that, the positive group converter SSP starts operating after passing between 11 and 1 of Δ-.

This ∆d between 1 and 1 prevents the positive group and negative group converters from operating at the same time, and the DC current that actually flows is 1.
It is determined based on the prior value of the time when d becomes completely zero.

The SSP stops operating, and after 6 hours, the ct r, y converter SSN starts operating. At this time, since Id<O, it is a seventh mode that regenerates power to the DC power supply Vd.

Actual DC current I, actual command value I (according to 1*, 1
υ1111 is performed so that d'l, 1, but at the time of switching when 1, 1 changes from positive to (,) or from negative to positive, the command value Id shown by the broken line is changed as shown by the solid line. Become an ID. That is, there is a period of positive←→(pause+9 where the current becomes zero when switching 1).

A few thousand milliseconds (msec) is sufficient for the rest period of the six guns, and there is no practical problem even if the power and regeneration occur frequently.

When 81 to the switch circuit is on and As2 is off, the DC current 1d is positive I! It is controlled by the T converter SSP as follows.

[If d>Id, the deviation εI='d-Id becomes a positive value, and the phase control V of the positive group converter SSP is controlled via the current control compensation circuit G, (S). , increases. Output voltage of positive group converter SSP.

(It increases in proportion to the horizontal phase control human power vcrP, and as a result, the DC current [d increases and is controlled to become I1 x I.

On the other hand, when Id becomes less than Id, the Q difference εI becomes a negative value and decreases the phase control human power vaP.

Therefore, the output voltage V, of the positive group converter SSP decreases, causing the direct current I, to decrease. Again, I = 1
It is controlled so that it becomes 6.

At this time, the compensation signal −kv−■ input to the adder AD
(1 is the one that generates the electric current J1 opposite to the DC power supply voltage Vd from the 11-kun Y-1 inverter SSrn (・, previous,
-12 current control 1? When the 1Δ signal from the +Iit circuit G, fS) is inferior, v, -v, and the DC voltage vd and iF convex. Regarding, the DC current 1 in this state
There is no increase in d by 1.

Next, control operation of DC current [d/! when switch circuit AS2 is on and As1 is off. :Explanation J-ru.

In this case, the n-group converter SSN operates and regenerates power to the DC power supply.

If I, > [, for example, [,=-90A, id=,
-100A), the deviation 81 is a positive value, and ``Municipal system■1
Through the compensation circuit G, (s), the phase 11 of the negative group convert SSN (control human power V = -GI(S) -αN ε 10K ・■d is reduced. Therefore, [■ v >■ and 'tK d, direct current 1d in the direction of the arrow
N increases and settles down to U', 1d' = I, 1.

Conversely, when l < I (for example, ld = d -100Δ, Id = -90A), the leakage εI becomes a negative value, and the phase υ control input ■ (xN
increase. Therefore, ■d decreases VN, and the DC current ■
is also controlled so that Ia''?Ia.

Next, the voltage wave height vCap of the high frequency phase advancing capacitor CAP
-VCaD becomes a positive value, and the voltage control compensation circuit G. (S
) to increase the DC current command value 1d. As mentioned above, the actual DC current 1d is adjusted according to the DC current command ItiI so that I L:I,1.
d controlled. This binding, the power P from the DC power supply ■d = ■
・I is supplied and stored as energy dd in the phase advancing capacitor CAP, and the voltage vcap
increase. , and finally, vcap “V cao
It calms down.

"V <V", M match, G difference ε. is a negative cap
cap Ame Tonari G. Decrease the DC current command value I through (S), and then set it to a value of (1.'d'F〈O and h, the energy of the advanced condenser l + cAP becomes DC current %: V
d, the voltage Vcap decreases, and V'rV
J: Controlled by sea urchins.

cap cap In this way, the voltage f of the phase advance capacitor CΔP is equal to the corresponding command +IIIV, J:Uc
ao to 1. Id group will be formed.

Next, by writing Naik U converter CC, AC electric separate M
The current supplied to [,I,[lA 1ill 1211
v Explain the sliding action.

4 [J3, here we will explain the case where an induction motor is used as the electric vJ machine M.

Figure 8 shows 11 of the circulating current type microconverter CC.
FIG. 1 is a block diagram showing the detailed configuration of the step section.

Corresponding to the control circuit shown in FIG. 1, the result is as follows.

First, the speed control circuit SPC in FIG. 1 is connected to the comparison section C in FIG.
3. Speed control auxiliary (α circuit 0N(S), excitation current setting device E
X, Performance 1 circuit CAL1 to CAL3.3 consists of a suction sinusoidal pattern generator PTG and multipliers MLU to M L,I.

In addition, the current control circuit A CR2 is the comparison 1s shown in FIG.
c-G6, current control ilI? l reimbursement circuit GU(S).

Gy (s), G14 (s) and Canada 3A1-A3
Consists of.

Further, the phase control circuit PH02 in FIG. 1 is constituted by phase control circuits PHC to PHC23 in FIG. 8.

First, the speed control II switching operation of the induction electric motor IlIM will be explained.

Secondary current Ir and excitation current ■ of the induction motor. A system in which the vectors are orthogonal to each other in a vector-like manner so that each can be controlled independently is known as vector control Li l m. Here, we take as an example the speed control using this method.

There are many literatures on vector control methods, so detailed explanations will be omitted. I will only state the essential points.

: L is a rotational pulse generator directly connected to the rotor of the motor 1) From G is a pulse train proportional to the rotational speed 1σω.

Comparator C, calculates this rotational speed N (-ω,) and its command value N
”, and the difference ε,=N” −N is the speed control t
Input to +li resent circuit G (s). G, (S) is derived from a proportional element or an integral element, etc., and the output is 1
~Gives the torque current command Ir.

In addition, the detected rotational speed value ω in 1νI is the excitation current setting device E.
The excitation current command of 1° is given manually to X.

[31 Input to the execution circuits CAL1-CAL2 to perform the next operation.

However, in the operator circuit CAL1, R*: Secondary resistance L": Secondary inductance The slip angular frequency ω is determined by the equation.

In addition, in the excitation circuit CAL2, by the calculation of the primary current I =
57W T” ・・・・・・・・・(18)Lm
By calculating c τ , the peak value I of the primary current command value I is determined.

FIG. 9 shows a current vector diagram of this galvanic conductor 1FJJR, so the exciting current I. and secondary current (torque° market current)
■There is an orthogonal relationship with 7, which is the generated torque T of this electric IJJ machine. can be expressed by the following formula.

Normal excitation...Current command I. At the end, a constant value is given, and the generated torque T of the electric motor. is controlled by changing the secondary current command ([-lux current command) I5.

However, when the rotational speed is operated at a speed higher than the rated value, field weakening control is performed and the excitation current setting device EX outputs an excitation current command I. may be changed depending on the rotational speed ω.

The edge angular frequency dispersion 11i obtained in this way
ω is input to the sine wave pattern generator B 111-G to obtain the next three-phase intermediate sine waves φ, φヮ, and φ.

φ = sin((ω 1ω)・t→−θ,)U
rs ρ ・・・・・・(20) φy=s+n((ω +ω3.ri・wo 〇 −r 2π/3) ・・・・・・(21
)2π/3) ・・・・・・(22
) These unit sine waves φ, φヮ, φ determine the frequency and phase of the single quantity flow I supplied to the induction motor b1M.

The multiplier ML −ML generates a three-phase medium-level sine wave φU,
Multiplying φV, φ and the wave height command ■Lm is the sum t! 3-phase current supplied to induction motor 81M (1 quantity...
(23) -2π/3) ・・・・・・(24)=2π/3)
(24) The vector aIl of the induction motor is the exciting current I and the secondary current 1. The advantage is that r can be controlled independently. Therefore, while keeping the excitation 1-ff flow 1 of the electric motor d constant, the generated torque can be controlled 2Ilη by changing the magnitude of the two quantity flows Ia, which is equivalent to DC 4. It is possible to achieve a rapid response time of 11 seconds.

Next, the primary current command (1r]1 given as above
The operation of controlling υIJ will be explained.

The lightning current 10.1V, I, is detected by the transformers zc-r, , crV, cr, shown in FIG.

This motor primary current detection value 1. IV! , are input to the comparators 04 to C6, respectively, and the command values 'U' 1.1 . Compare each with.

The Luli control operation will be explained by taking the U-phase current as an example.

Comparator C4 calculates the actual value of 1° and the command value r. and the deviation ε,=I. −[, current control till complement (rj
input to the circuit GtI(s). G, (s) performs integration or proportional amplification and inputs the output to the phase control circuit pFic21 via the q adder Δ1. Also, G (s>
The inverted value of the output is input to the phase υ control circuit PH023 via the adder A3.

The output voltages V1 to V3 of each converter ss-5s3 are the input voltages v of the phase control circuits PHC21 to PHC23.
~■ is proportional to.

α1 α3 Therefore, when IU>Iu, the deviation εU becomes a positive value and the phase control circuit P
HC21 input voltage■. Increase 1, converter S8
1's output voltage 1 is increased in the direction of the arrow in FIG.

At the same time, the input voltage of the phase control y11 circuit P HC.

3, and the output voltage v3 of the converter S83 becomes the first
Generate in the opposite direction to the arrow in the figure. As a result, output current I3 of converter S81 increases and output current I3 of converter S83 decreases.

As a result, the U-phase current of the motor is 1 -1. -13 is If)
It is controlled so that IU''=IU.

Conversely, when Iu<Iu, the deviation εU becomes a negative value, and the output voltage (2) decreases and (3) increases.

Therefore, ' 11 ''''' 1-■3 decreases, and if it is converted to 'σ in a 10 sinusoidal waveform, the actual current will also become 1 41, and the sinusoidal current will be j O (supplied to the induction motor M). That will happen.

Upstream of phase and W phase 1. I14 and others are similarly controlled.

Therefore, the rotational speed N of the induction motor M is controlled in the following manner.

When N” > N, the deviation ε becomes positive, and
The I-lux current (secondary current) command I7 is increased via the control compensation circuit GN(S).

As a result, the induction shown in Figure 9? The first order and phase angle θ of the 1f motive are increased, and the actual current 1. IV.

rUl,t
J Follow-up control is performed accordingly.

Thus, the actual 2 quantity flow 1 of the induced electric current nM increases, and the generated torque T. Increase and accelerate. As a result, N increases and is controlled to become NL:N''.

Conversely, when N''<N, the deviation ε8 becomes a negative value, decreasing the torque current command I4 and changing the phase angle from the first order to 0.
decrease. Therefore, the generated 1-lux T is decreased, and the rotational speed N is also decreased to N'yN*.

In the above embodiment, a delta-connected circulating current cycloconverter was used as the circulating current cycloconverter, but a circulating current cycloconverter with normal positive and reverse converters for three phases can be used in the same manner as in 5. Needless to say, it is possible.

Further, in the above embodiment, the case where an induction motor is used as the AC motor has been described, but the present invention can be similarly applied to the case where a synchronous motor, a reluctance motor, a hysteresis morph, etc. are driven.

Further, in the above embodiment, a so-called non-circulating ff1i type double converter has been described as the double converter, but it goes without saying that a circulating current type double converter can be implemented in the same manner. In that case, there is no need to reduce the output current (DC current 1d) to -00 when switching the forward/reverse converter 03 operation, and smooth running and regenerative operation can be achieved.

〔Effect of the invention〕

As is clear from the above IJ2 and J:, according to the present invention, the following J: effect can be obtained by 1q.

DC power 1 [Receives power from the source, establishes a high-frequency reactive power source for the phase advance capacitor, and uses the voltage of this high-frequency reactive power source to naturally commutate the double converter and circulating current type cycloconverter. . Therefore, compared to conventional automatic inverters, the AC electric coil can be driven at variable speed without using forced commutation circuits or self-extinguishing elements (transistors, G TOs, etc.). This increases the reliability of the device and allows for larger capacity products.

In addition, the circulating current type cycloconverter that drives the AC motor can obtain an output frequency that is equal to the input frequency (the frequency of the voltage applied to the phase advance capacitor), and can rotate the AC motor at an ultra-high speed. . For example, if the frequency r of the voltage applied to the phase advance capacitor is 5001
-ll, it is possible to supply sinusoidal currents IU, l, IIA with a frequency of about 0 to 50011z to the armature winding of the AC power line. In the case of a two-turn electric motor, the rotational speed is °30
．． It also becomes 0OOru, making ultra-high-speed operation possible. As a result, the blower motor, which conventionally had to be sped up using a gear, does not need a gear, which improves operating efficiency, and makes it possible to reduce the size and weight.

Also, increase the rotation speed to 3. When the speed is about OOOrpm, the number of poles of the electric fIJR can be reduced to 20, which not only reduces the torque ripple at low speeds, but also improves the accuracy of speed control by an order of magnitude compared to the conventional method. .

Furthermore, the current IU supplied to the motor.

Iv, 1- is controlled to a sine wave 00, and a very small device with 1-leak ripple is jrJ. At the same time electric 14i
There is no lJ sound, and a quiet rotating machine can be provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is an equivalent circuit diagram for explaining the operation of the main parts of the embodiment, and FIGS. 33 and 4 are the same embodiment. 5 is a time chart for explaining the operation of the main part of the same embodiment, FIG. 5 is an isometric diagram for explaining the operation of the main part of the same embodiment, and FIG. (■Block diagram without showing details of the converter control section, Fig. 7 is a time chart for explaining the operation of the j-i11 parts, Fig. 8 is a diagram of the control section of the neucro converter that constitutes the above embodiment) A block diagram showing the details, and FIG. 9 is a vector diagram for explaining the operation of the control unit.■...DC power supply, Ld...DC reactor 1-C
0NV...2 small converter, CAP...phase advance capacitor, CC...circulating cycloconverter, M...
AC motor, SSP, SSN...positive group, n-type converter, SS1-SS3...separately excited converter, TR...
High frequency transformer, 1-L3...DC reactor 1-L,
CT, CT, CT, CT, ・=,
1ffi current detector, tlV PToa, ... voltage detector, D... rectifier circuit, △V
R...Voltage control circuit, SPC...Speed control circuit, Δ
CR1゜A CR2...'+tf flow control circuit, PHC
l, PHC2...phase control circuit, O20...external oscillator. Applicant's agent Mr. Sato - Yuchi 2 fig° Seimo 3 z

Claims (1)

[Claims] A double converter in which the DC sides of two converters connected in antiparallel are connected to a DC power source via a reactor, a phase advance capacitor connected between the AC side terminals of this double converter, and a phase advance capacitor whose input side is connected to the phase advance capacitor. a circulating current type cycloconverter connected to a capacitor and whose output side is connected to an AC motor, and controlling the double converter so that the peak value of the voltage of the phase advance capacitor is approximately constant; An AC motor comprising: a control means for controlling the cycloconverter so as to supply the AC motor with a variable frequency current in which the lagging reactive power of the cycloconverter is equal to the leading reactive power of the phase advance capacitor. Drive device.