JPH01318567A - Driver for wound-rotor type induction generator motor - Google Patents

Abstract

PURPOSE:To reduce the input capacitance of a cycloconverter at the time of steady operation by setting the output constitution of three-phase output cycloconverters to Y-connection at the time of pumping start and by switching Y-connection to -connection at the time of steady operation. CONSTITUTION:At the time of pumping start, an AC breaker 5 is opened and AC breakers 6, 7U-7W and a short-circuiting AC breaker 8 are closed. Thus, the output constitution of cycloconverters 3U-3W becomes Y-connection and a wound-rotor type induction generator-motor 1 is started at low frequency. When starting is completed, the AC breakers 7U-7W and short-circuiting AC breaker 9 are opened. Then, AC breakers 9U-9W are closed and cycloconverters 3U-3W are -connected, and the secondary winding of wound-rotor type induction generator-motor 1 is AC-excited by the cycloconverters 3U-3W.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a drive device for a wound induction generator motor that is driven at variable speed using a cycloconverter that excites a secondary winding with alternating current.

[Conventional technology]

Figure 6 is, for example, 1986, Proceedings of the National Conference of the Institute of Electrical Engineers of Japan, P-17'? 3 is a main circuit configuration diagram of the conventional "pumped storage start/stop test results of variable speed pumped storage power generation system", and in the figure, 1 is a wound induction generator motor (hereinafter referred to as generator motor ), 2 is connected to the primary winding of this generator motor 1 via an AC breaker 5.
This is a main transformer to which a secondary winding is connected, and the primary winding of this main transformer 2 is connected to the power grid. 3 is a cycloconverter connected to the secondary winding of the generator motor l via an AC breaker 7; 4 is a cycloconverter transformer whose secondary winding is connected to the cycloconverter 3; The primary winding of the cycloconverter transformer 4 is connected to the secondary winding of the main transformer 2 via an AC breaker 6. Reference numeral 8 denotes a short-circuit AC breaker connected to the primary winding of the generator motor 1. Next, the operation will be explained. First, at the time of pumping start, the AC breaker 5 is opened, the AC breaker 6.7 and the short-circuit AC breaker 8 are closed, and the cycloconverter 3 performs a low frequency start using the generator motor 1 as an electric motor. In this case, the maximum output voltage of the cycloconverter 3 is assumed to be EiM, which is generally about 10 to 15% of the secondary discharge voltage E20 of the generator motor 1.
is required for starting. The characteristics of the generator motor 1 at the time of starting are schematically shown in FIG. In FIG. 7, during the period of time 0''t+, the output voltage E2 of the cycloconverter 3 (i.e., the voltage of the secondary winding of the generator motor 10) and the output frequency f2 (i.e., the frequency of the secondary winding of the generator motor 1) are Ez/f2 = constant, which corresponds to the case of starting with so-called constant torque, and the torque TGM of the generator motor 1 is almost constant, allowing the maximum starting torque to be generated.The pump-turbine is in a state close to no load when starting with pumped water. Therefore, the load torque TLo in that case is 5 to 10% or less of the rated torque TLN.Therefore, the rotational speed N of the generator motor 1 is the difference between the torque TGM of the generator motor 1 and the load torque TLO. At time t, the output voltage E2 of the cycloconverter 3 reaches the maximum output voltage ELM, and after the time t, the cycloconverter 3 is operated with the output voltage E2=E2M=constant, and only the output frequency f2 rotates. Since it increases in accordance with the speed N, it corresponds to the case of starting with so-called constant output characteristics.As the output frequency f2 of the secondary winding of the generator motor 1 increases, the voltage drop of the generator motor 1 increases. increases, the output current 12 of the cycloconverter 3 (that is, the secondary winding of the generator motor 1) decreases, and together with the decrease in magnetic flux due to the constant output characteristics of the generator motor 1, the output current 12 of the generator motor 1 decreases.
The torque TG,4 decreases. Therefore, as the rotational speed N increases, the difference between the torque TGM and the load torque TLO becomes smaller, and the rate of increase in the rotational speed N becomes slower. Therefore, if you want to shorten the starting time, use the cycloconverter 3
It is desirable that the maximum voltage E2° is as large as possible. The rotational speed N of the generator motor 1 reaches the steady operating speed N at time t2.
When the speed reaches the lower limit speed of s or more, the operation of the cycloconverter 3 is temporarily stopped and the short-circuiting AC breaker 8 is opened. Thereafter, the cycloconverter 3 is operated again to excite the secondary winding of the generator motor 1 with alternating current, and the voltage 811 frequency f of the primary winding of the generator motor 1 is controlled. Said E+, f+
When the voltage and frequency match the voltage and frequency of the secondary winding of the main transformer 20, the AC breaker 5 is closed and steady operation begins. In addition,
Steady operating speed NN is shown as NM=(1±5N)No,
The lower limit speed is NH=(IS,J)No. Here, SN is the rated slip of the generator motor 1, No is the synchronous speed, and the secondary characteristic of the wound photoelectric motor 1 is the 8th
Shown as shown. Generally, the rated slip S during steady operation
N is SN "0.05 to 0.1, and in this case, the rated output voltage IEzN of the cycloconverter 3 is almost proportional to the slip, EzN = (0.05 to 0.1) E2°, and when starting Compared to the required maximum output voltage E2.4 of the cycloconverter 3, it is approximately 1/1.5 ~
It will be about 1/2.

[Problem to be solved by the invention]

Since the drive device for the conventional wound induction generator motor is configured as described above, the input voltage of the cycloconverter 3, that is, the secondary voltage of the cycloconverter transformer 4, is the maximum output of the cycloconverter 3 at the time of pumped water starting. Voltage E2
Since the input capacity of the cycloconverter 3 becomes large during steady operation, and the input reactive power also becomes large, the phase advance capacitor for power factor correction is connected to the cycloconverter transformer. There were problems such as the need to provide it on the primary side of 4. This invention was made to solve the above-mentioned problems, and provides a drive for a wound induction generator motor that can reduce the input capacity of the cycloconverter 3 during steady operation and also reduce the input reactive power. The purpose is to obtain equipment.

[Means to solve the problem]

The drive device for a wound induction generator motor according to the present invention operates a Y connection switch so that the output configuration of a three-phase output cycloconverter can be connected in a Y manner when starting as an electric motor, and allows a Δ connection to be established during steady operation. The Y and Δ connection switches of the two systems can be mutually switched and controlled by operating the Δ connection switch.

[For use]

The drive device for the wound induction generator motor according to the present invention changes the output configuration of the three-phase output cycloconverter to Y at the time of pumping start.
The connection switch connects the Y-connection to operate as a motor, and during steady operation, the three-phase output cycloconverter switches its output configuration to the Δ-connection using the Δ-connection switch.

【Example】

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the same parts as in FIG. 6 are indicated with the same reference numerals. In FIG.
, 3W is, as is well known, configured with a three-phase bridge connection having arms in which thyristors are connected in antiparallel, as shown in FIG. 2, for example. 4U, 4V, 4W are transformers for cycloconverters, and each transformer is 4U, 4V. A 4W secondary winding is connected to each of the cycloconverters 30.
It is connected to the input side of 3V and 3W, and each primary winding is commonly connected to the secondary winding of the main transformer 2 via an AC breaker 6. 70. TV? W is the cycloconverter 3U,
An AC breaker that acts as a 3V, 3W Y connection switch, and each of the cycloconverters 30, 3V,
The 3W output end (terminal side not connected to the generator motor 1) is Y-connected between 3UN, 3VN, and 3VN, and the other end is commonly connected to the neutral wire 3N. 9U, 9V, 9W are AC breakers that act as Δ connection switches for the cycloconverters 3U, 3V, 3W, and for example, the AC breaker 9U connects 3VP at one end of the V-phase cycloconverter 3■.
and one end gUN of the U-phase cycloconverter 3U. Next, the operation will be explained. First, when starting pumping, the AC breaker 5 is started, and the AC breaker 6, 70° 7V, ? W
Then, the short-circuiting AC breaker 8 is closed, and the cycloconverter 3U, 3V, and 3W start at a low frequency. In this case, the output configuration of the cycloconverter 30° 3V, 3W is Y
connection, and the output line voltage E2 is given by the +11 formula. Ex = ffX1.35 Ha cos a: /
'Fr (11 Here, E is the input voltage of the cycloconverter 3U, 3V. 3W is the input voltage, α is the phase control angle.The maximum output voltage ELM that can be generated by the cycloconverter 3U, 3V, 3W is α- When αmin#30', EZMζ1.43Es (21
becomes. Next, when the start is finished, the cycloconverter 3U. Stop operation of 3V, 3W, AC breaker 7U, 7V. 7W and AC breaker 8 for short circuit are started. Next, the AC circuit breakers 9U, 9V, 9W are closed, and the cycloconverter 30.3V, 3W is operated again to turn off the generator motor l.
The next winding is excited with alternating current. Then, the voltage Vl of the primary winding of the generator motor 1 and the frequency f. When the voltage and frequency match the voltage and frequency of the secondary winding of the main transformer 2, the AC breaker 5 is closed and steady operation begins. In this case, the cycloconverter is 3U, 3V. Since the 3W output configuration is Δ connected, the output line voltage E2
is given by equation (3). Ez = 1.35E, cos a/fY
(31 At this time, cycloconverter 3U, 3V,
The maximum output voltage E2N of 3W is EzNζ0.83Es when α=αm1n=30'
(41. That is, (21, (from formula 41, EZM""EZN""
It becomes H. For example, if the rated slip is 5N = 0.07, EzN
= 0, 07 Ex. The maximum output voltage Ezx at startup is E21 EtN# 0, 12 Ezo
Therefore, the required starting voltage (0,1 to 0.15) Ez. It is possible to enter the engine and start it. Next, the input capacities of the cycloconverters 3U, 3V, and 3W will be explained. If the secondary winding current of the generator motor 1 during pumped water starting is rzs, and the secondary winding current of the generator motor 1 during steady operation is tzH, then general ．．
It is 5. The input current I of the cycloconverter 3U, 3V, 3W is given by the following equation. At the start of pumping = Is = ('i) completedXIzs (5
1 During steady operation, r, = C "7 teeth x 12 N/f Co'0
．． 4712N (6) Now, I
If ts/12N=0, 5, then from equation (5), when starting pumping, Is #0. 41 INN
(7) (6), (Comparing Type 71, during steady operation, the capacity increases by approximately 15% compared to when starting with pumped water. However, in the conventional system that does not perform Y-Δ switching of cycloconverters 3U, 3V, and 3W, During steady operation, the capacity becomes 82 Its (81, which is approximately 100% more than when starting pumping. Therefore, when Y-Δ switching is performed, the capacity during steady operation becomes (6
1, <81 formula, it is possible to reduce the capacity by about 75%. Note that in the above embodiment, the cycloconverter 3U. Although we have explained an example in which AC breakers 7U, 7V, 7W and 9U, 9V, 9W are provided as switches for 3V and 3W ¥-Δ connection, cycloconverters 3U and 3
At the time of Y-Δ switching of V and 3W, the operation of the cycloconverter is temporarily stopped and each of the AC breaker 7U and TV
, 7W and 9U, 9V. Since it reduces the current of 9W to zero, it may be an AC switch, and the AC breaker 8 for shorting the primary winding of the generator motor 1 may also be an AC switch. Further, in the above embodiment, the cycloconverter 3U. 3V, 3W is shown in a 3-phase bridge connection configuration with arms in which sirisks are connected in anti-parallel.
As shown in a), it may be a 12-phase cycloconverter in which a three-phase Brifuji circuit is connected in two stages in cascade, or as shown in FIG. 3(b), a circulating current suppressing reactor 3
It may be a circulating current type cycloconverter in which three-phase bridge circuits are connected in antiparallel through L. In the above embodiment, an AC breaker or an AC breaker 70 is used as the Y connection switch of the cycloconverter.
Although we have described an example in which 7V and 7W are provided, it is also possible to use a semiconductor switch made of Cyrisk, etc., as shown in Fig. 4 (In this case, the Δ connection switch 9U and 9V during steady operation.9W) If an overvoltage occurs in the secondary winding of the generator motor 1 due to a short-circuit accident in the power system while the circuit is being operated with the circuit closed, turning on the semiconductor switch 7U. switch 9
Since the secondary winding of the generator motor 1 is short-circuited via U, 9V, and 9W, overvoltage can be suppressed at high speed. Also, as shown in the figure, a semiconductor switch 7U. Connect the common connection point 3N of 7V and 7W to the neutral wire N of the generator motor 1.
An AC switch 10 may be provided in between, and in this case, the AC switch 10 is closed during steady operation, and when a three-phase unbalanced overvoltage occurs in the secondary @ line of the generator motor 1, the AC switch 10 is closed. Is the above semiconductor switch? By selecting and turning on 0.7V and 7W, it is possible to quickly suppress the voltage of the phase in which overvoltage has occurred. In addition, in the above embodiment, AC breaker 7U, 7 for Y connection
V,? We have explained the operation of short-circuiting the secondary winding of the generator motor 1 by using W as an overvoltage suppressing means during steady operation, but as shown in FIG.
U, 7V, 7W to each cycloconverter 30, 3V, 3
Connect the output terminals 3UN, 3VN, and aWN of W, and connect the semiconductor switches IIU, IIV, and IIW to the resistors 12
U, 12V, 12W series body to each cycloconverter 3
AC breaker for Y connection of 0,3V, 3W 7U, 7V,
? connected to the W side, and the semiconductor switch 11tJ, IIV
, IIW and resistor 12U, 12V. The common connection point of 12W may be connected to the neutral wire N of the generator motor 1. In this case, the AC breaker 9U is used for Δ connection during steady operation. When an overvoltage occurs in the secondary winding of the generator motor 1 while operating with 9V and 9W closed, the semiconductor switches IIU, IIV, and IIW are selected and turned on, and the resistors 12U and 12V are turned on. 12W, the secondary winding of the generator motor 1 is short-circuited, the overvoltage can be suppressed at high speed, and when the overvoltage is suppressed, the semiconductor switches 11U, IIV, IIW
can be turned off and normal operation can be continued. However, if overvoltage persists, use an AC breaker 7U, 7V, 7W for Y connection.
By closing the circuit, overvoltage can be completely suppressed. In addition, when the above-mentioned semiconductor switches IIU, IIV, IIW are provided between the connections between each cycloconverter 3U, 3V, 3W and the generator motor 1 3UP, 3VP, 3WP, the cycloconverter 3U, 3V at the time of pumped water start. The output voltage E214 of 3W is the semiconductor switch 11U. 11V and 11W, the voltage stress of the semiconductor switches IIU, IIV, and IIW becomes large, whereas as shown in the figure, the voltage stress of the semiconductor switches IIU, IIV, and IIW increases.
The semiconductor switches IIU, IIV, IIW are on the V and TW sides.
If you install AC breaker 7 for Y connection when starting pumping,
0. The semiconductor switch 11U is closed because the TV and 7W are closed. 11V and IIW are zero, and since the secondary winding voltage Ezs of the generator motor 1 during steady operation is applied, the semiconductor switch 110. There is an effect that a relatively low withstand voltage value of IIV, 11W can be applied. In addition, in the above embodiment, description of a surge absorber such as an arrester that suppresses a steep overvoltage that occurs in the secondary winding of the generator motor 1 during steady operation is omitted, but as illustrated in FIG. 5, each cycloconverter Between the output terminals of 3U, 3V, 3W or each semiconductor switch 110. IIV, II
A surge absorber 13U or 14U may be provided between both ends of W. In this case, compared to the case where the surge absorbers 13U and 14U are connected between the secondary windings of the generator motor 1, the limit voltage value of the surge absorber can be relatively lowered, and each cycloconverter 3U and 3V , 3W and each semiconductor switch 11U. It is relatively easy to coordinate overvoltage protection with 11V and IIW. Furthermore, although the above embodiment describes a variable speed drive method using a cycloconverter for a wound induction generator motor directly connected to a pump-turbine, it is of course possible to drive a load other than a pump-turbine; for example, a load is the pump and blower. A similar effect can be obtained even if the motor is driven at variable speed as a wound induction generator motor using a fan or the like.

【Effect of the invention】

As described above, according to the present invention, when starting a wound induction generator motor as an electric motor, a cycloconverter with a three-phase output is connected in a Y manner for low frequency starting, and during steady operation, the cycloconverter is connected in a Δ manner. Since the cycloconverter is configured to operate in a constant state, the input capacitance of the cycloconverter can be reduced, and a circuit can be obtained in which the capacitance of the phase advance capacitor can be reduced. Further, by configuring the Y-connection switch as a half-quad switch, there is an effect that overvoltage generated in the secondary winding of the generator motor during steady operation can be suppressed at high speed. Further, a semiconductor switch is provided in series with a resistor between the Y-connection AC breaker and the neutral wire of the secondary winding of the generator motor, and the semiconductor switch is connected to the secondary winding of the generator motor. By turning on only when the overvoltage occurs, the overvoltage can be suppressed, and when the overvoltage disappears, steady operation can be continued, and the semiconductor switch has the advantage of being able to use a relatively low withstand voltage value.

[Brief explanation of the drawing]

1 and 2 are main circuit configuration diagrams showing a drive device for a wound induction generator motor according to an embodiment of the present invention, and FIGS.
FIG. 5 is a main circuit configuration diagram showing another embodiment of the present invention, FIG. 6 is a main circuit configuration diagram showing a conventional drive device for a wound-type induction generator motor, and FIG. 7 is a starting-up diagram of a wound-type induction generator-motor. The characteristic diagram, FIG. 8, is a steady operation characteristic diagram of the wound induction generator motor. 1 is a wound induction generator motor, 3,3U, 3V. 3W is a cycloconverter, 5.6 is an AC breaker, 7
U, 7V, 7W are AC breaker (Y connection switch),
9U, 9V, 9W are AC breaker (Δ connection switch)
It is. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Patent applicant Mitsubishi Electric Corporation (ol 3UN, 3VN, 3WN fb) Figure 4 Figure 5

Claims (1)

[Claims] A winding in which the primary winding of a wound induction generator motor is connected to the power grid via an AC breaker, and the secondary winding is connected to a 3-phase output cycloconverter to enable frequency and voltage control. In a drive device for a linear induction generator-motor, when starting the wound-type induction generator-motor as a motor, the primary winding of the wound-type induction generator-motor is short-circuited by an AC breaker, and the output of the three-phase output cycloconverter is The present invention is characterized by comprising a Y-connection switch for Y-connection, and a Δ-connection switch for connecting the primary winding to the electric power system and connecting the output of the cycloconverter to the Δ-connection during steady operation of the wound induction generator motor. A drive device for a wound induction generator motor.