JP2000262099A - Lateral flow compensating device for ac generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize and make light weight the constitution of a lateral flow compensation device adopted, when an AC generator is operated in parallel with the other power source and to reduce manufacture man-hours. SOLUTION: A voltage source-type current/voltage converter 6, in which a magnetic circuit 6-1 and a hole element 6-2 are combined and whose power loss is extremely small, is adopted. The current signal of an AC generator 1 is converted into a voltage via magnetic flux. Voltage and the secondary side voltage of transformers 4 and 7 detecting generator voltage are added vectorially in arithmetic circuits 8 and 9A. Then, voltage is full-wave rectified and is changed into DC voltage and is outputted as a feedback voltage signal in a generator control system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to reduce the size and weight of a cross flow compensator used to prevent cross flow of an ineffective component flowing between two power supplies when an AC generator is operated in parallel with another power supply. The present invention relates to an improvement of a cross flow compensator for an AC generator, which is suitable for the present invention.

[0002]

2. Description of the Related Art A conventional cross current compensator, such as a cross current compensator 5 shown in FIG. 4, comprises a current transformer 6, a transformer 7, a resistor 8, and a full-wave rectifier circuit 9. Works like

In FIG. 4, when the AC generator 1 is operated in parallel with another AC power supply 2 and stable three-phase RST AC power is supplied to the load side, if the generator voltage changes for any reason, A cross flow of the reactive component flows between the two power sources, and as a result, the power factor of the generator fluctuates. The cross current compensator 5 generates a DC output voltage e whose magnitude changes in accordance with the fluctuation of the generator power factor, and supplies the DC output voltage e to the automatic voltage regulator as a feedback voltage signal. The secondary side current of the high-voltage type current transformer 3 whose secondary side for detecting the generator current i1 is grounded is input to the current transformer 6 in the cross current compensator 5, and the secondary side current i2
Is supplied to the resistor 8 to generate a voltage v1 corresponding to i2 across the resistor. On the other hand, the secondary voltage of the high-voltage type transformer 4 whose secondary side for detecting the generator voltage is grounded is input to the transformer 7 in the cross current compensator 5, and the secondary voltage v2 and the voltage v1 Are generated in series, and a composite vector voltage v3 of (v2-v1) is generated.

FIG. 5 shows a vector diagram of each of the voltages v1, v2, and v3 when the power factor of the generator is 1.0. The locus of the composite vector voltage v3 changes according to the fluctuation of the power factor of the generator. The generator moves on a circle indicated by a dashed line, and its absolute value, that is, the magnitude increases when the generator power factor is in the late direction, and decreases when the generator power factor is in the forward direction. The voltage v3 is converted to a direct current by the full-wave rectifier circuit 9 shown in FIG. 4, and a voltage e corresponding to the magnitude of v3 is output.
Note that 0 V is a zero voltage line.

[0005]

In the conventional cross current compensator constructed as described above, current-current exchange is performed by using the current transformer 6, and the secondary current i2 as a current source is converted into a voltage. In this case, a large amount of power loss occurs in the resistor 8, and therefore, a resistor having a specification equivalent to, for example, 20 W is required. However, there is a problem that it is difficult to reduce man-hours in manufacturing. SUMMARY OF THE INVENTION It is an object of the present invention to provide a cross flow compensator for an AC generator, which solves the above-mentioned problems (problems) of the conventional device and can reduce the number of manufacturing steps of the cross current compensator.

[0006]

According to the present invention, a magnetic circuit and a Hall element are combined to solve the above-mentioned problems.
A voltage source type current-to-voltage converter with very small power loss is adopted, the generator current signal is converted to voltage via magnetic flux, and the signal is processed by the operational amplifier of the integrated circuit. As a result, the cross current compensator was downsized to a level that allows wiring on a printed circuit board, and the number of manufacturing steps was reduced.

[0007]

FIG. 1 is a circuit diagram showing an embodiment of a circuit according to the present invention.
4) are denoted by the same reference numerals as in FIG. In FIG. 1, 5 is a cross current compensator, 6 is a current-voltage converter, 7
Is a transformer, 8 is an operational amplifier, and 9A is a full-wave rectifier circuit. The configuration of the full-wave rectifier circuit 9A will be described later.

The current-voltage converter 6 comprises a magnetic core 6-1 and an operational amplifier 6-4.
-1, the Hall element 6-2 is inserted into the air gap,
A magnetic circuit consisting of a core and an air gap is input to the coil 6-3 wound around the core 6-1 and receives the secondary current of the high-voltage type current transformer 3 whose secondary side for detecting the generator current i1 is grounded. The AC voltage generated by the Hall element is amplified by the operational amplifier 6-4 due to the action in the magnetic flux generated in the step (a), and a voltage v1 is output.

On the other hand, the secondary voltage of the high-voltage type transformer 4 whose secondary side for detecting the generator voltage is grounded is input to the transformer 7, and the secondary voltage v2 and the voltage v1 are calculated. Vector addition by the amplifier 8 (v2 · R3 / R2-v1
R3 / R1) is generated.

FIG. 2 is a vector diagram of the voltages v1.R3 / R1, v2.R3 / R2, and v3 when the power factor of the generator is 1.0, and is the same as FIG. That is, the trajectory of the composite vector voltage v3 moves on the circle indicated by the dashed line in accordance with the fluctuation of the generator power factor, and its absolute value, that is, the magnitude increases when the generator power factor is delayed. , And decreases in the forward direction. The voltage v3 is converted to a direct current by a full-wave rectifier circuit 9A constituted by, for example, an absolute value calculation circuit as illustrated in FIG. 3, and a direct current output voltage e corresponding to the magnitude of the v3 is output. 1 and 3 is a zero voltage line.

The DC output voltage e of the cross current compensator 5
Is supplied as a feedback voltage signal to the automatic voltage regulator,
If the generator voltage rises or falls and a cross current flows between the AC generator 1 and another AC power supply 2, the DC output voltage e, ie, ,
The feedback voltage signal changes, the exciting current of the generator is adjusted, and the generator voltage is automatically controlled in a direction to compensate for the cross current.

[0012]

As described above, the cross current compensator for an AC generator according to the present invention employs a voltage-source type current-to-voltage converter having a very small power loss to convert the generator current into a voltage, Since the processing is performed by an operational amplifier or the like, the following excellent effects are obtained. (1) Each component becomes small and can be mounted on a printed board. (2) As a result, the man-hours required for assembling, wiring, and the like of the cross current compensator can be significantly reduced, which contributes to cost reduction. (3) An example of miniaturization of each component is as follows. That is, the current transformer, which is a main component of the conventional circuit, has a volume of 1
00 × 70 × 60 (mm), weight 1.5 kg, transformer volume 60 × 35 × 40 (mm), weight 500 g, resistor volume 81 × 13 × 21 (mm), weight 30
g, whereas in the main components of the present invention corresponding to these, the current-voltage converter has a volume of 20 × 20 × 21 (m
m), weight 17g, and transformer volume 36 × 33 × 31
(Mm), weight 92 g, and other components can be extremely reduced because they are composed of weak electric components and integrated circuits.

[Brief description of the drawings]

FIG. 1 is a connection diagram showing a circuit configuration of a cross flow compensator for an AC generator according to the present invention.

FIG. 2 is a functional explanatory diagram of the cross current compensator according to the present invention.

FIG. 3 is a connection diagram illustrating a configuration of a full-wave rectifier circuit employed in the cross current compensator according to the present invention.

FIG. 4 is a connection diagram showing a circuit configuration of a cross current compensator for an AC generator according to the related art.

FIG. 5 is an explanatory diagram of functions of a cross current compensator according to the related art.

[Explanation of symbols]

 1: AC generator 2: AC power supply 3: Current transformer 4, 7: Transformer 5: Cross current compensator 6: Current-voltage converter 6-1: Magnetic core 6-2: Hall element 6-3: Coil 6-4, 8: Operational amplifier

Claims (1)

[Claims] 1. A cross flow compensator used when an AC generator is operated in parallel with another power supply, wherein a Hall element is inserted into an air gap provided in a part of a magnetic core. Supply the secondary current of the current transformer that detects the generator current to the coil wound around the coil, and amplify the AC voltage generated by the Hall element by the action of magnetic flux generated in the magnetic circuit consisting of the core and the air gap. The current-to-voltage converter to be output and the secondary voltage of the transformer for detecting the generator voltage are vector-added by an arithmetic circuit, full-wave rectified and converted to DC voltage, and the feedback voltage signal in the generator control system And a means for outputting power for use in the AC generator.