JPS6160679B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for controlling an alternating current generator, and in particular,
This invention relates to an AC generator control method that is optimal for minimizing input power depending on load conditions.

[Conventional technology]

In an alternator connected to a DC load via a conventional thyristor rectifier, when the set value of the DC load fluctuates, the terminal voltage of the alternator is kept constant and the thyristor gate is controlled. It was carrying a load.

FIG. 1 is a circuit diagram of a power supply device including an alternating current generator connected to a DC load via a thyristor rectifier.

The alternator 1 is driven by a drive motor 2 . Further, the drive motor 2 rotates at a constant speed using an AC power source as a power source. The output voltage of the alternator 1 is determined by a control device comprising an AVR 3 and an excitation device 4, which controls the alternator field winding 5 to output a specified voltage. The DC load 6 is connected to the alternating current generator 1 via a thyristor rectifier 7, and controls the gate of the thyristor rectifier 7 to change the conduction rate.

[Problem that the invention seeks to solve]

In order to perform partial load control in a device with such a configuration, the terminal voltage of the alternator 1 is kept constant and the gate of the thyristor rectifier 7 is controlled to switch from the full load operation shown in Fig. 2A to the Fig. 2 As shown in B, control was being carried out to reach partial load operation. By the way, the terminal voltage of the AC generator 1 is proportional to the magnetic flux flowing through the stator core of the generator 1, and the iron loss of the AC electric machine 1 is the magnetic flux density of the stator core (magnetic flux including the core). Since it is determined by the magnetic path (divided by the cross-sectional area of the magnetic path) and its weight, the iron loss is ultimately proportional to the terminal voltage of the alternator 1. However, in the conventional control for partial loads as described above, the terminal voltage of the alternator 1 is constant, so even if the load becomes small, the core loss does not change and the loss ratio to the load increases. The drawback is that the input power consumption is large relative to the supplied power. Furthermore, the output current from the thyristor device 7 has a distorted waveform, as shown in FIG. 2B, and therefore has the drawback of containing many harmonic components. In particular, this is a significant drawback in loads where the DC load fluctuates intermittently, such as short-circuit generators.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a control method for an alternator that can control the output terminal voltage according to the load state and minimize the required input according to the output voltage in the case of a partial load. be.

[Means for solving problems]

The present invention utilizes the fact that armature copper loss is generally smaller than iron loss among alternator losses, and controls the AVR to adjust the terminal voltage of the alternator to the partial load state during partial load operation. The iron loss is controlled to be reduced by lowering the iron loss accordingly. In addition, two types of excitation devices and AVR are provided depending on the load condition, and control is performed to reduce the input required for the entire power supply device.

Figures 3A and 3B represent waveforms obtained by the control method of the present invention, with the waveforms during full load operation as shown in Figure 3A, and the generator terminal voltage from E during partial load operation as shown in Figure 3B. The AVR and exciter are controlled to reduce the iron loss to E′, thereby reducing iron loss and required input. In this case, it goes without saying that a thyristor device may also be used if necessary. In particular, when the load changes suddenly, it is difficult for the AVR to follow it, so it is controlled by a thyristor device.

The effects of the present invention are noticeable when the partial load operation is a low load operation of, for example, 5% to 10%, and the load operates intermittently as described above.

Therefore, the first invention of the present application adjusts the output voltage of an alternator connected to a DC load via a thyristor rectifier by adjusting the excitation current applied to the excitation winding of the alternator. In the method for controlling an alternating current generator, when the direct current load is a partial load, the terminal voltage of the alternating current generator is controlled to be varied so that the alternating current generator bears only the electric power commensurate with the electric power consumed by the load. It is characterized by this.

Further, the second invention of the present application provides an AC power generation system in which the output voltage of an AC generator connected to a DC load via a thyristor rectifier is adjusted by adjusting the excitation current applied to the excitation winding of the AC generator. In the control method for the machine, when the DC load is a partial load, the terminal voltage of the alternator is controlled to be varied so that the alternator carries only the electric power commensurate with the electric power consumed by the load; The present invention is characterized in that power fluctuations of the load are suppressed and controlled by the thyristor rectifier.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 4 is a block diagram showing a device configuration for realizing an embodiment of the alternating current generator control method according to the present invention.

The difference between the device shown in Fig. 4 and the device shown in Fig. 1 is that two AVRs and two excitation devices are provided, one set of AVR and one exciter is used for high-load control, and one set of AVR and one exciter is used for high-load control. The only difference is that one set is dedicated to control during low loads, and the other configurations remain unchanged. Therefore, in FIG. 4, the same members as used in FIG. 1 are given the same reference numerals and explained. That is, two units are installed: the AVR 8 and excitation device 9, which have good characteristics under low loads, and the AVR 10 and excitation device 11, which have good characteristics under high loads, and when the load 6 is high load, the AVR 1
0 and the excitation device 11 to control the field winding 5, and when the load is low, the AVR 8 and the excitation device 9 can control the field winding 5.
2 is used by switching.

However, when performing partial load operation, the AVR
The core loss of the generator 1 is reduced by controlling the AVR 8 in particular among 10 and 8 to lower the terminal voltage of the alternator according to the partial load state.

Such control was achieved as follows.

If the output of the generator 1 is P [w], the terminal voltage of the generator 1 is V [v], its output current is I [A], and the power factor on the load side is cosφ, then P is P=√3VI cosφ is given by This output power P of the generator 1 is consumed by the load 6. When the load 6 fluctuates and its power consumption fluctuates, the AVR 8 is controlled to keep the current I constant and to vary the voltage V so that only the necessary power consumption is always supplied to the load 6. I'll do it. As mentioned above, the terminal voltage V is proportional to the iron loss, and the current I is related to the copper loss, and among the losses of the alternator 1, the armature copper loss is generally smaller than the iron loss. For this reason, the constant current control/variable voltage control as described above results in smaller losses from the overall loss perspective.

Furthermore, when the power of the load 6 fluctuates significantly, the current I is varied by controlling the gate of the thyristor rectifier 7 to cope with the load fluctuation.

By operating with such a configuration, it is possible to realize a power supply device with low loss and less required input.

FIG. 5 is a circuit diagram showing the configuration of a second device most suitable for implementing the embodiment of the present invention.

The device shown in FIG.
In order to avoid the AVR10 from not working
The power is supplied from an AC power supply. 1st
Unlike the conventional example shown in the figure, the output voltage of the alternator 1 itself drops during partial load, so the output voltage cannot be diverted only to the low load AVR 10 (the high load AVR 8 has an output voltage This consideration is not necessary as the condition is high).

〔Effect of the invention〕

As is clear from the above, according to the present invention, the power required for continuous low-load operation is reduced, and power consumption can be reduced.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of a power supply device including an alternator connected to a DC load via a thyristor rectifier, and Figures 2A and B each show the full load and partial load outputs obtained by the device in Figure 1. Voltage waveform diagrams, Figures 3A and 3B are full negative and partial load output voltage waveform diagrams obtained by the present invention, Figure 4 is a circuit diagram showing the first embodiment most suitable for realizing the present invention, Figure 5 The figure is a circuit diagram showing a second embodiment most suitable for realizing the present invention. 1... AC generator, 5... Excitation winding, 6... DC load, 7... Thyristor rectifier, 8, 10...
...AVR, 9,11...excitation device.

Claims (1)

[Claims] 1. An alternator that adjusts the output voltage of an alternator connected to a DC load via a thyristor rectifier by adjusting an excitation current applied to an excitation winding of the alternator. The control method is characterized in that when the DC load is a partial load, the terminal voltage of the AC generator is controlled so as to cause the AC generator to bear only the electric power commensurate with the electric power consumed by the load. How to control an alternator. 2. In a method for controlling an alternating current generator connected to a direct current load via a thyristor rectifier, the output voltage of the alternating current generator is adjusted by adjusting the excitation current applied to the excitation winding of the alternator, When the load is a partial load, the terminal voltage of the alternator is controlled to be varied so that the alternator only carries the power corresponding to the power consumed by the load, and the thyristor rectifier is used to control the voltage of the load. A method for controlling an alternator, characterized by suppressing and controlling power fluctuations.