JP2911337B2 - Starting device for AC-excited synchronous machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starting device for an AC-excited synchronous machine used in a variable speed pumped-storage power generation system.

[0002]

2. Description of the Related Art FIG. 5 is a circuit diagram of a conventional starting device for an AC-excited synchronous machine. In FIG. 5, 1 is an AC-excited synchronous machine, 2 is a short-circuit switch for short-circuiting the primary side of the AC-excited synchronous machine 1, and 3 is a power converter for supplying a variable frequency power to the AC-excited synchronous machine 1. , 11 are transformers for supplying power to the power converter 3, and 12 are generator breakers for opening and closing a power supply line to the AC-excited synchronous machine 1. The starting procedure of this AC-excited synchronous machine is described in, for example,
3-15684.

Next, the operation of the conventional AC excitation type synchronous machine starting device will be described. First, the primary side of the AC-excited synchronous machine 1 is short-circuited by the short-circuit switch 2 to make the AC-excited synchronous machine the same configuration as the induction motor.
Next, from the secondary side of the AC excitation type synchronous machine 1, the power conversion device 3
Thereby applying a low frequency power supply. As a result, the AC-excited synchronous machine 1 starts rotating by the rotating magnetic field. Next, the output frequency of the power conversion device 3 is set to a frequency obtained by adding a constant frequency to the rotation speed of the AC excitation type synchronous machine 1, and the rotation speed is increased to a specified rotation speed. Next, the power converter 3 is stopped, and the short-circuit switch 2 is opened. And
The AC-excited synchronous machine 1 and the power converter 3 are synchronously connected. After the ascending speed , a variable speed pumping operation is performed.

[0004]

The starting device of the conventional AC-excited synchronous machine is configured as described above, and a low-frequency current is induced on the primary side of the AC-excited synchronous machine 1. In order to open the short-circuit switch 2, it is necessary to reduce the low-frequency current on the primary side to zero within a short time. The reason is that, if it takes too much time to open the short-circuit switch 2, the power conversion device 3 is stopped, the rotation speed is reduced, and the synchronization cannot be performed. In addition, as the short-circuit switch 2, a DC breaker for breaking a large current is required. For this reason, there has been a problem that a large capacity and expensive circuit breaker is required.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and at the time of pumping start, a low-frequency current induced on the primary side of an AC-excited synchronous machine is reduced to zero within a short time. It is an object of the present invention to provide an AC-excited synchronous machine starting device capable of performing the following.

[0006]

A starting device for an AC-excited synchronous machine according to a first aspect of the present invention includes a control circuit 3a for controlling a power converter 3, and opens the primary side of the AC-excited synchronous machine 1. In this case, the control circuit 3a controls the secondary-side voltage generation component of the AC excitation type synchronous machine to zero. A starting device for an AC-excited synchronous machine according to a second invention comprises:
A short-circuit breaker 4 for short-circuiting and opening the secondary side of the AC-excited synchronous machine 1 is provided. When the primary side of the AC-excited synchronous machine is opened, the AC-excited synchronous machine is opened by the short-circuit breaker. The secondary side of the machine was short-circuited. The starting device for an AC-excited synchronous machine according to the third invention is provided with a gate turn-off thyristor 9 for each phase on the secondary side of the AC-excited synchronous machine 1 to open the primary side of the AC-excited synchronous machine. , said gate
The gate of the auto turn-off thyristor 9 is turned on by the control circuit 3a to short-circuit the secondary side of the AC-excited synchronous machine.

[0007]

The starting device for an AC-excited synchronous machine according to the first invention, when opening the primary side of the AC-excited synchronous machine,
The control circuit controls the secondary-side voltage generation component of the AC-excited synchronous machine to zero. Therefore, the low-frequency current on the primary side of the synchronous machine becomes zero in a short time. In the starting device of the AC-excited synchronous machine according to the second invention, when the primary side of the AC-excited synchronous machine 1 is opened, the secondary side of the AC-excited synchronous machine 1 is short-circuited by the short circuit breaker 4. . Therefore, the low-frequency current on the primary side of the synchronous machine becomes zero in a short time. Third
The starting device of AC-excited synchronous machine in the invention of, when opening the primary side of the AC-excited synchronous machine 1, a gate turn
The off- thyristor 9 is gated on by the control circuit 3a, and the secondary side is short-circuited. Therefore, the low-frequency current on the primary side of the synchronous machine becomes zero in a short time.

[0008]

【Example】

Embodiment 1 FIG. Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram of an AC-excited synchronous machine according to Embodiment 1 of the present invention. In FIG. 1, 1 is an AC excitation type synchronous machine, 2 is a short-circuit switch for short-circuiting the primary side of the AC excitation type synchronous machine, 3 is a power converter for supplying a variable frequency power supply to the AC excitation type synchronous machine, 3a is a control circuit for controlling the synchronous machine, 11 is a transformer, and 12 is a generator breaker. The power converter 3 receives power from the transformer 11 and supplies low-frequency power to the rotor of the AC-excited synchronous machine 1 under the control of the control circuit 3a. In the AC-excited synchronous machine according to the first embodiment, the power converter 3 can attenuate the primary current in a short time. Therefore, the short-circuit switch 2 can be opened in a short time.

Next, the operation of the AC-excited synchronous machine according to the first embodiment will be described. At the start of pumping, the primary-side short-circuit switch 2 is closed, and the AC-excited synchronous machine 1 has the same configuration as that of the wound induction motor. Next, a variable frequency power is applied by the power converter 3 from the secondary side of the AC excitation type synchronous machine 1. Then, the rotation speed of the AC-excited synchronous machine 1 is increased to a specified rotation speed. At this time, a low-frequency current having a difference between the variable frequency power supply frequency applied from the secondary side and the rotation speed is induced on the primary side of the AC-excited synchronous machine 1. After the speed increase, the power converter 3 is controlled by the control circuit 3a to open the short-circuit switch 2 and perform the variable speed pumping operation, and the secondary-side voltage generation component of the AC excitation type synchronous machine 1 ( V
q) is set to zero. As a result, the low-frequency current becomes zero, and the short-circuit switch 2 can be opened.

FIG. 4 is a waveform diagram showing a change in the primary current (point P in FIG. 1) by the device of this embodiment. In FIG. 4, the horizontal axis represents time, and the vertical axis represents the change in the magnitude of the primary current. (A) is a waveform after the AC-excited synchronous machine has been accelerated to the rated speed. At this time, only one phase is displayed with the short circuit breaker 4 open. (B) is a waveform when the power converter 3 is temporarily stopped. At this time, the power converter 3 is stopped at time T1.
(C) is a waveform when the voltage generation component is reduced to zero from the secondary side of the AC excitation type synchronous machine. At this time, the power converter 3 is stopped at time T1 and the voltage generation component is reduced to zero at time T2. I have to. (D) is a waveform when the short circuit breaker 4 described later is closed. At this time, the power conversion device 3 is stopped at the time T1, and the short circuit breaker 4 is stopped at the time T3.
Is closed. (E) is a waveform when a short circuit is formed in the power converter 3 described later. At this time, the power converter 3 is stopped at time T1 and short-circuited by the power converter 3 at time T4.

Embodiment 2 FIG. In the first embodiment, the case where the voltage generation component (Vq) is reduced to zero by the power converter 3 has been described. However, as shown in FIG. 2, a short circuit breaker is provided on the secondary side of the AC excitation type synchronous machine 1. 4 is provided, and the short circuit breaker 4 is closed (short-circuited) as an alternative to setting the voltage generation component (Vq) to zero.
The low-frequency current on the primary side of the AC-excited synchronous machine 1 can be reduced to zero. One of the short circuit breakers 4 is connected to the short circuit, and the other is connected to the power converter 3 and the rotor of the AC-excited synchronous machine 1. The operation of the device of the second embodiment is based on the voltage generation component (V
The difference is that q) is not controlled by the power converter 3 but is set to zero by the short circuit breaker 4. The waveform of the primary current at this time corresponds to FIG. 4D described above.

Embodiment 3 FIG. In the second embodiment, the case where the short circuit breaker 4 is provided has been described. However, the above-described short circuit may be configured by the internal circuit of the power converter 3. In FIG. 3, reference numeral 5 denotes an inverter for converting DC to AC, and reference numeral 6 denotes a converter for converting AC supplied from the system to DC. Reference numeral 7 denotes one phase of the internal circuit of the inverter 5, and 9 denotes a gate turn-off thyristor (GT) for controlling on / off of current.
O) and 8 are diodes.

Next, the operation of the power converter will be described. To construct a short circuit of the AC-excited synchronous machine 1 controls the gate turn-off thyristor. This short-circuit operation is the same for the three phases A, B, and C. That is, the current from the C phase, gate turn-off thyristor 9a, diode 8a, midpoint N, diode 8b, via a gate turn-off thyristor 9b conducts an A-phase, short-circuits the A phase and the C phase. In this way, the other phases are similarly short-circuited. The waveform at this time is shown in FIG.

[0014]

According to the first aspect of the present invention, the control circuit for controlling the power converter is provided, and when the primary side is opened, the voltage generation component on the secondary side of the AC excitation type synchronous machine is set to zero. since so controlled by the control circuit as induced in the primary side
Low-frequency current to zero in a short time,
AC-excited synchronous machines can now be synchronized synchronously,
In addition, there is no need to use a large-capacity primary circuit breaker, so that the device can be manufactured at low cost. According to the second invention, the AC-excited synchronous machine is provided with a short-circuit breaker for short-circuiting and opening the secondary side, and when opening the primary side, the secondary side is short-circuited by the short-circuit breaker. To reduce the low-frequency current induced on the primary side to zero within a short time.
AC synchronous machine can be synchronized
In addition, there is no need to use a large-capacity primary-side circuit breaker, so that the device can be manufactured at low cost. According to the third invention, a gate turn-off thyristor is provided for each phase on the secondary side of the AC excitation type synchronous machine, and when the primary side is opened, the thyristor is gated on by the control circuit, and the secondary side is turned on. since so as to short-circuit, one
Zero the low-frequency current induced on the secondary side within a short time
Can be used to synchronize AC-excited synchronous machines without fail.
In addition, there is no need to use a large-capacity primary circuit breaker, so that the device can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a starting device of an AC-excited synchronous machine according to Embodiment 1 of the present invention.

FIG. 2 is a circuit diagram showing a starting device of an AC-excited synchronous machine according to Embodiment 2 of the present invention.

FIG. 3 is a circuit diagram of a power conversion device provided in a starting device of an AC-excited synchronous machine according to Embodiment 3 of the present invention.

FIG. 4 is a waveform diagram showing a waveform of a primary current by the starting device of the AC-excited synchronous machine according to the embodiment of the present invention.

FIG. 5 is a circuit diagram showing a starting device of a conventional AC excitation type synchronous machine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 AC excitation synchronous machine 2 Short circuit switch 3 Power converter 3a Control circuit 4 Short circuit breaker 5 Inverter 6 Converter 7 One phase of inverter 8 Diode 9 Gate turn-off thyristor (GTO)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H02P 9/00-9/48

Claims (3)

(57) [Claims] 1. An AC-excited synchronous machine and a power converter for supplying a variable frequency to a secondary side thereof. At the time of startup, the primary side of the AC-excited synchronous machine is short-circuited, By the power converter, the AC excitation synchronous machine is started by supplying low-frequency power to the AC excitation synchronous machine, and in a normal operation, the AC excitation synchronous machine starting device opens the primary side. Controlling the power converter when opening the primary side.
To make the secondary-side voltage generation component of the AC-excited synchronous machine zero.
Control circuit, and the AC excitation type
After setting the voltage generation component on the secondary side of the synchronous machine to zero,
A starting device for an AC-excited synchronous machine characterized in that its side is opened . 2. An AC-excited synchronous machine and a power converter for supplying a variable frequency to a secondary side thereof. At the time of starting, the primary side of the AC-excited synchronous machine is short-circuited. By the power converter, the AC excitation synchronous machine is started by supplying low-frequency power to the AC excitation synchronous machine, and in a normal operation, the AC excitation synchronous machine starting device opens the primary side. When opening the primary side, the two
Short circuit to short-circuit the secondary side and make the secondary-side voltage generation component zero
Circuit breaker.
Set the secondary-side voltage generation component of the magnetic synchronous machine to zero before
A starting device for an AC-excited synchronous machine, wherein the primary side is opened . 3. An AC-excited synchronous machine and a power converter for supplying a variable frequency to a secondary side of the AC-excited synchronous machine. When starting, the primary side of the AC-excited synchronous machine is short-circuited. Thus in the power converter, the low-frequency power source to start the Riue Symbol AC-excited synchronous machine by the supplying to the AC-excited synchronous machine, in normal operation, AC-excited synchronous machine to open the primary side in the starting device, opening to each phase of the secondary side of the AC-excited synchronous machine Rutotomoni provided gate turn-off thyristor, the primary side
When turning on the thyristor, the secondary side
Zero the secondary-side voltage generation component by short-circuiting
A control circuit is provided.
After the voltage generation component on the secondary side of the
A starting device for an AC-excited synchronous machine, characterized in that it is opened .