JPH02136096A - Operation system of three-phase wound-rotor induction motor - Google Patents

Abstract

PURPOSE:To maintain normal speed control and power control by passing predetermined zero-phase current even under one phase missing state thereby supplying three-phase balanced current and voltage to a rotor winding. CONSTITUTION:Upon a fault of a phase-c reversible converter 30c, switches 7a, 7e are opened while switches 7d, 7h are closed. Then cos(thetas+2pi/3) and sin(thetas+2pi/3) are inputted to multipliers 5a, 5b and multiplication of a current command id2* and cos(thetas+2pi/3) and that of iq2* and sin(thetas+2pi/3) are carried out. As for id2*.cos(thetas+2pi/3 the sign is inverted through a sign inverter 6 while operation of -id2*.cos(thetas+2pi/3)+iq2*.sin(thetaS+2pi/3) is carried out through an adder 1c. Thereafter, the difference between -id2*.cos(thetas+2pi/3)+iq2*.sin(thetaS +2pi/3) as a zero-phase current command and an actual i02 is operated in an adder 1d. Then the difference is added to respective phase outputs from a two- phase/three-phase converter 4 in adders 1e, 1f, 1g through a zero-phase current regulator 2c thus producing voltage commands for phases a, b and c.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an operation method for a wound three-phase induction motor. A power conversion device such as a cycloconverter is connected to the child winding and adjusts the frequency, phase, amplitude, etc. of the current or voltage in the rotor winding, thereby changing the rotation speed of the induction motor to the synchronous speed determined by the system frequency. In addition to controlling the power factor along the top and bottom, the power factor on the stator side was also controlled. This paper relates to the operation method of a wound three-phase induction motor using the so-called supersynchronous static Servius method.

(Prior Art) Conventionally, the drive system shown in FIG. 2 is known as a drive system for a wound three-phase induction motor (hereinafter simply referred to as an induction motor when necessary) based on a super-synchronous stationary Servius system. In the figure, 100 is a power supply system, and this power supply system 1
00 to stator windings 41a, 41b, and 41c of each phase of an induction machine 40 are connected via a circuit breaker 50. Further, the primary side of a transformer 20 is connected to the power supply system 100, and the secondary side thereof includes reversible converters 30a, 30b, which are comprised of thyristors and the like, provided corresponding to each phase of the induction machine 40.
A cycloconverter 30 with 30c is connected. Furthermore, the reversible converters 30a, 30b, 30
The common terminal on the output side of c is connected to the neutral point of the rotor windings 42a, 42b, and 42c of the Y-connected induction machine 40, and is connected to the neutral point of the rotor windings 42a, 42b, and 42c of the reversible converter 30a.

Each other terminal on the output side of 30b and 30c is connected to the rotor winding 42.
A, 42b, and 42c are connected to one end of each to form a main circuit.

In the drive system configured in this way, the amplitude and phase of the output voltage or current of the cycloconverter 30,
Power supply system 100 by controlling and adjusting frequency etc.
Appropriate power is supplied to the rotor windings 42a, 42b, 42c from the
The rotational speed of the stator winding 416.41b is controlled above and below the synchronous speed determined by the system frequency, and the stator winding 416.41b,
The power factor of the power supplied to the 41c side, that is, the primary side, can be adjusted. Moreover, reversible converters 30a and 30b
, 30c and the transformer 20, regenerative braking operation is also possible.

(Problem to be Solved by the Invention) In the above drive system, three reversible converters 30a, 30b, 30c forming the cycloconverter 30.
If one of them fails or stops and one phase is open, the output three-phase current of the cycloconverter 30 becomes unbalanced and the induction motor 40 There was a problem in that a uniform rotating magnetic field could not be supplied to the speed control system, making it impossible to perform normal speed control and causing the speed control system to stop.

The present invention was proposed in order to solve the above problems, and its purpose is to Even if one of them fails or stops, the remaining two reversible converters will supply current and voltage from the rotor so that the torque generated by the induction machine becomes a ripple-free DC amount, ensuring normal speed control. The object of the present invention is to provide a method of operating a wound three-phase induction motor that can be maintained.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides, in an operating system of a wound three-phase induction motor operated by a so-called supersynchronous stationary Servius system, each motor is connected to a rotor winding, In addition, when one of the reversible converters constituting the cycloconverter stops and one phase is open, multiple sine wave signals based on the d-q axis orthogonal coordinate current command value and the difference between the stator angle and rotor angle are generated. calculate a zero-phase current command value flowing through a zero-phase circuit provided between the reversible converter and the rotor winding from
This zero-phase current command value is added to each phase voltage command value of the rotor winding via a zero-phase current regulator to obtain a new each-phase voltage command value.

(Function) When the basic equation of a wound three-phase induction motor is expressed by a d-q axis orthogonal rotating coordinate system expanded to the d axis parallel to the stator side voltage and the q axis perpendicular to the stator side voltage,...・・・・・・
...(1) becomes. Here, ed is the d-axis component of the stator side (-secondary side) voltage of the induction machine, eq□ is the q-axis component, ed2 is the d-axis component of the rotor side (secondary side) voltage, and eQ is the same. The q-axis component, id □ is the d-axis component of the stator current of the induction machine, iq is also the q-axis component, id2 is the d-axis component of the rotor current, iq
2 is the q-axis component, r□ is the stator winding resistance, r2 is the rotor winding resistance, xl is the stator leakage inductance, x2
is the rotor leakage inductance, xll is the effective inductance, and ω1 is the stator angular frequency.

ω2 is the rotor angular frequency, and ωS is ω, -ω2.

Also, the d-q weight of voltage and current is: ・・・・・・・・・・・・(2) ・・・・・・・・・・・・(3) ・・・・・・・・・・・・・・・(4) ・・・・・・・・・・・・(5) Here, eo, 1o1 is the stator side voltage, the zero-sequence component of the current, e621102 is the rotor side voltage,
Zero-sequence component of current, i al + i J , i Ql
, l ag 11 bz Hic2 is each phase current on the stator side and rotor side, θ is the stator angle (angle between stator a phase (a□ phase) and d axis), O5 is θ□-02 And O
2 is the rotor angle (the angle between the rotor a phase and cat phase) and the d axis.

At this time, the active power Pe on the stator side, the reactive power Qe on the rotor side, and the active power P e, and reactive power Qez on the rotor side are as follows.

Pe, = (3/2) (ed, -i a1+e ql・i
q1+2e, 1-i, 1)・・・・・・・・・・・・
...(6)Q e, = (3/2) (e d,・
i q, -e q, ei ctz)・・・・・・・・・
......(7) Pe, = (3/2) (e d, +
i d, +e q% i q2+2e, i・i o,
)・・・・・・・・・・・・・・・(8) Qe2= (
3/2) (e d, II i q, -e q2・i d
x)・・・・・・・・・・・・・・・(9) Here, assuming that the stator winding is directly connected to the power supply system and is in a three-phase balanced state, id and iql is the direct flow rate.

Therefore, in order to make the electric power of the stator and rotor windings of the induction machine a DC amount without ripple, the ct-q axis current of one rotor winding should be made into a DC amount.

Suppose that the reversible converter corresponding to the C phase of the rotor winding fails and the C phase becomes open-phase, l ct, ==A, l q2=
Assuming that a current B flows through, ia and :O in the above equation (5), . . . (10) is obtained. From the above formula, ioz = B −5in (θs+2π/3) −A−
cos (θs+2π/3)=-n Ycos (θ
s+27G/3+δ) ・・・・・・・・・・・・(
11) ia2 =: /Ding Zeng Ko Ding sin (O5+π/
3+δ) ・・・・・・・・・・・・(12)ib2=
4 fvηYsin (O5+δ) −・・−・=・
(13) Here, sin δ = B / fK]
Self, eosδ=A/fK]1.

As shown in equations (11), (12), and (13) above, when inputting the current command value x d2 = A giq2 = B, input the value shown in equation (11) as the zero-phase current command value. By doing so, i a□, ib2 and xcz (=o) shown by equations (12) and (13) flow,
It is possible to generate a uniform rotating magnetic field and supply ripple-free power.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows voltages that output voltage command values for each phase of the rotor of an induction machine for controlling the firing angle of the switching elements of the reversible converters 30a, 30b, and 30c that constitute the cycloconverter 30 of FIG. A command value output circuit 10 is shown. In the same figure, 1a is the rotor side d-axis current command value id2
The adder 1b receives the rotor-side q-axis current command value iq2 and the d-axis current actual value id2 with the polarity shown, and the adder 1b receives the rotor-side q-axis current command value iq2 and the d-axis current actual value id2 with the polarity shown. 2a and 2b are each adder 1a.

■ A d-q axis current regulator such as a PI (proportional integral) regulator connected to the output side of b, 3 is the output from each current regulator 2a, 2b and a two-phase sine wave signal sinθs, c01! θS(
Here, O5 is the difference θ, -02) between the stator angle θ1 between the stator a phase and the d axis and the rotor angle θ2 between the rotor a phase and the d axis, as described above. 4 is a two-phase/three-phase converter le that converts the secondary voltage vector into three phases.

If, 1g is an adder in which each phase output of the two-phase/three-phase converter 4 is inputted to one input terminal 6, and 5a,
5b, the dl1ll current command value id2. and the q-axis current command value iq1. are respectively input to the - input terminal, and switches 7a to 7d, which will be described later, are connected to other input terminals.
Multiplier to which signals from a to 7h are input, 6 is multiplier 5
1c is an adder to which the output signal of the sign inverter 6 and the output signal of the multiplier 5b are inputted with the indicated signs; 1d is the output signal of the adder 1c and rotation. Zero-sequence component i of child current. 2(=i O2+ x b,
+ x ox) is inputted with the symbol shown, an adder 2
C is a zero-phase current regulator such as a PI regulator to which the output signal of the adder 1d is input as a zero-phase current command value. and,
The output signal of the zero-sequence current UR moderator 2C is output from the adder 1a,
If and Ig are input to the other input terminals with the symbols shown in the figure, and the output signals of these adders 1e, If, and Ig become voltage command values for each phase (a, b, and C phase) of the rotor of the induction machine. There is.

Further, the multiplier 5a receives Y O (V), cos θs, cos (0g-2π/
3), cos(θS+2π/3) is also the multiplier 5
b, O(V), si via switches 78 to 7h
nθs, 5in(θs−2π/3), 5in(θs
+2π/3) can be input. These switches 7a to 7h are the reversible converters 30a and 30a shown in FIG.
Switches 7a and 7e are interlocked and closed by a signal indicating that both 30b and 30c are normal, and switches 7b and 7f are interlocked by a signal indicating that the reversible converter 30a corresponding to the a phase has failed. The switches 7c and 7g are closed in conjunction with the signal indicating that the reversible converter 30b corresponding to the B phase has failed, indicating that the reversible converter 30c corresponding to the C phase has failed. The switches 7d and 7h are closed in conjunction with the signal.

In such a configuration, reversible converters 30a, 30b
.

30c all working properly, cycloconverter 30
When the adder 1c is operating normally, the switches 7a and 7e are closed and 0 [v] is input, so the output of the adder 1c is 0.
And also i. Since 2=O, zero-phase current regulator 2
The output of the regulator 2c is obtained such that the command value given as the input of c becomes O. On the other hand, each axis current command value id2
The deviation between ・, 192・ and each actual value id, , iq□ is d-
q@Current yA is input to the vector rotator 3 via moderators 2a and 2b, vector rotation is performed between sin θs and Cos θS, and the two-phase/three-phase converter 4 converts it into a three-phase quantity.

These three-phase quantities are added to the output of the zero-phase current regulator 2c described above by adders 1e, If, and Ig, respectively, and the added output is added to the reversible converter 30 as a voltage command value for each phase.
Firing angle commands a, 30b, and 30c are generated.

Further, for example, if a failure occurs in the reversible converter 30c corresponding to the C phase and this reversible converter 30c is disconnected, io,=Q. Here, as mentioned above, < x c+2
If the command value ==A, x q□=B is given, then 1
In order for the rotor winding to produce a uniform output, i,, =-
A −cos(θs+2tc/3)+B −5in(
08+27C/3) is passed, i a,=A-cosθ5-B-sinθs+1ozi
b, =A-cos(θs-2π/3)-B-sin(
θS-2? C/3)+i,.

It is necessary to pass a current into the a-phase and b-phase. That is, in this embodiment, the switches 7a and 7e are opened due to a failure of the C-phase reversible converter 30c, and the switch 7d is opened.
, 7h closes, cos (θs+2π/
3L 5in (θ, +2 x /3) are input to multipliers 5a and 5b, respectively. And these multipliers 5
a, 5b, current command value id2・ and cos(O
Multiplication with s+:)c/3) and 19□・and sin(0g
+2π/3) is performed, and id,...cog(θ
s + 2 x i 3 ) is inverted by the sign inverter 6, and then -1d2
11・cos (0g+2c/3)+i q2...s
in (θs+2π/3) is calculated.

After that, the adder 1d sets the above - as the zero-phase current command value.
1d2...cos(θs+2yc/3) + i q
2...sin (O5+2π/3) and the actual value i. 2 is calculated and sent to an adder via a zero-phase current regulator 2c.
, le, if, +4 is used to add each phase output from the two-phase/three-phase converter 4.

Voltage command values for each phase of a, b, and c are obtained.

With the above operation method, even if the reversible converter 30c corresponding to the C phase fails, a uniform rotating magnetic field is applied to the rotor windings by passing the desired zero-sequence current, and the ripple is eliminated. Can supply power without

In addition, although the above embodiment has been explained assuming a failure of the C phase, the present invention is of course similarly applicable to a failure of the reversible converter 30a or 30b corresponding to the other a phase or b phase. . Furthermore, in the above embodiment, the explanation is based on a system with a zero-phase (neutral point) circuit as shown in Fig. 2, and in a system without a zero-phase circuit during normal operation, the zero-phase circuit It is necessary to provide

(Effects of the Invention) As described above, according to the present invention, one reversible converter out of three reversible converters configuring the cycloconverter connected to the rotor winding of a wound three-phase induction motor Even if a failure occurs and operation becomes impossible, resulting in an open-phase condition, unbalanced current or voltage can be supplied by passing a specified zero-sequence current on the condition that the zero-sequence circuit is connected. This has the effect of being able to supply three-phase balanced current and voltage to the rotor windings, thereby maintaining normal speed control and power control.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a voltage command value output circuit to which an embodiment of the present invention is applied, and FIG. 2 is a block diagram of the main circuit of a drive system for a wound three-phase induction motor based on the hyperperiodic stationary Servius system. 18-1g... Adder 2a, 2b... d-q axis current regulator 2c... Zero-phase current regulator 3... Vector rotator 4... Two-phase/three-phase converter 5a, 5b... Multiplier 6...
・Sign inverter 7a to 7h...switch 10
...Voltage command value output circuit 30...Cycloconverter 30a-30c...Reversible converter 40...Wound three-phase induction motor 41a-41c...Stator winding 42a-42c...
・Rotor winding 100...Power system patent applicant Fuji Electric Co., Ltd.

Claims (1)

[Claims] The stator winding is connected to a power supply system, each phase of the rotor winding is connected to three reversible converters constituting a cycloconverter, and the rotor winding is In the operation method of a wound three-phase induction motor, which is a wound three-phase induction motor in which a zero-phase circuit is provided between a wire and a reversible converter and is operated by a supersynchronous static Servius method, among the reversible converters, When one phase is open when one unit stops, d
- Calculate the zero-phase current command value flowing through the zero-phase circuit from the q-axis orthogonal coordinate current command value and a plurality of sine wave signals based on the difference between the stator angle and the rotor angle, and calculate the zero-phase current command value flowing through the zero-phase circuit. An operating system for a wound three-phase induction motor, characterized in that the values are added to each phase voltage command value of the rotor winding via a zero-phase current regulator to obtain a new each phase voltage command value.