JPH01170328A - Serial compensation type voltage variation compensator - Google Patents

Abstract

PURPOSE:To compensate a voltage variation together with a waveform distortion and a flicker by interposing, in series with an adding polarity, a compensation power source for always generating a compensating voltage in response to the variation in the voltage of a power source of a system side between the system side power source and a load. CONSTITUTION:A compensation power source 10 for always generating a compensating voltage VH in response to the variation in the voltage VS of a system side power source 1 is interposed in series with an adding polarity between the power source 1 and a load 7. The power source 10 rectifies by a rectifier 2 the power source voltage CVS to charge a capacitor 3 having a large capacity and opens/closes an inverter 4 by a signal responsive to the variation in the voltage VS output from a controller 8, thereby generating a voltage V1. The voltage V1 is applied to the primary side of a coupling transformer 5, the voltage VH is generated from its secondary side, added to the voltage VS as a voltage VL, and applied to the load 7. Thus, the variation in the voltage having large varying width, and the variation in the voltage having a small varying width, such as a waveform distortion, a flicker or the like can be compensated.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a series compensation type voltage fluctuation compensator that is inserted in series between a power supply on the grid side and a load to compensate for voltage fluctuations in the power supply on the grid side in series. It is related to.

[Conventional technology]

Conventionally, instantaneous voltage drop compensators have been put into practical use as compensators for voltage fluctuations in power distribution systems.

As shown in FIG. 4, the instantaneous voltage drop compensator includes a rectifier circuit 2 that full-wave rectifies the voltage V of the grid-side power supply 1 to obtain DC power, and a rectifier circuit 2 that performs full-wave rectification on the voltage V of the grid-side power supply 1 to obtain DC power, and a system that performs charging using the DC power supplied from the rectifier circuit 2. A DC capacitor for compensating power storage, for example, a large-capacity electrolytic capacitor 3, and a compensation voltage V! for compensating for the voltage drop in the voltage V of the grid-side power supply 1 supplied with power from the electrolytic capacitor 3. an inverter 4 that generates an output voltage v1, a coupling transformer 5 for series compensation in which the output voltage v1 of the inverter 4 is applied to a primary winding and a secondary winding is inserted between the grid side tit and the load 7, and a coupling transformer. The main component is a bypass switch 6 that short-circuits both ends of the secondary winding No. 5. Note that the inverter 4 is connected to the grid side power supply l.
It is controlled by a control circuit 8 that detects the voltage drop in the voltage V.

Further, a voltage drop of more than 10% in the grid-side power supply 1 is detected by the voltage drop detection circuit 9, and the output of the voltage drop detection circuit 9 is used to determine whether the inverter 4 is activated or not, and whether the bypass switch 6 is turned on or off. - Shutdown is controlled.

This instantaneous voltage drop compensation device performs full-wave rectification of the voltage V of the grid-side power supply 1 in a rectifier circuit 2 to obtain DC power when the grid-side power supply 1 is normal, and uses this DC power to constantly power the electrolytic capacitor 3. The battery is charged, and the bypass switch 6 is turned on so that the voltage (2) of the power supply 1 on the grid side is applied to the load 7 as it is.

When an instantaneous voltage drop occurs in the grid-side power supply 1 and the voltage V of the grid-side type a] The DC power accumulated in the capacitor 3 operates the inverter 4 to increase the voltage V of the grid side power supply 1.
By generating a compensation voltage v1 corresponding to the drop in , and adding this compensation voltage v1 to the voltage vs of the grid side power supply 1 via the series compensation coupling transformer 5 and applying it to the load 7, the grid side power supply The load voltage VL across the load 7 is always kept constant regardless of the instantaneous voltage drop of the voltage V1.

FIG. 5 is a voltage waveform diagram showing voltage compensation by the instantaneous voltage drop compensator.

The solid line in FIG. 5 1al shows a waveform diagram of the voltage V of the grid-side power supply 1 when a slight voltage fluctuation and an instantaneous voltage drop occur. In the same figure (a), a minute voltage fluctuation other than an instantaneous voltage drop with a fluctuation width of 10% or less occurs between times 1) and 12, and an instantaneous voltage drop with a fluctuation width of more than 10% occurs after time t2. It shows that you are doing it. The broken line in the figure (al) shows the waveform of the voltage v, 1 during normal operation.

5) shows a waveform diagram of the compensation voltage v1 outputted from the inverter 4 with respect to the fluctuation of the voltage V of 51g (al). This shows that the compensation voltage v1 is not outputted from the inverter 4 during this period, and the compensation voltage v1 is outputted from the inverter 4 after time t2.

FIG. 5 1al shows a waveform diagram of the load voltage vL applied to the load 7. In the same figure (C), since the compensation voltage v1 is not output from the inverter 4 between times 1) and 12, the load voltage ■ becomes lower than the normal voltage vL' shown by the broken line, and after time t2, the inverter 4 outputs the compensation voltage v1. Compensation voltage from 4■
Since 1 is output, this indicates that the load voltage (■) is normal.

[Problem that the invention seeks to solve]

However, this instantaneous voltage drop compensation device
The bypass switch 6 is shut off only when the voltage V, decreases by exceeding the drop width 10%, and the inverter 4 is activated to generate the compensation voltage v1, so the drop width such as instantaneous voltage drop etc. Although it is possible to compensate for voltage fluctuations with large fluctuations exceeding 10%, it is not possible to compensate for voltage fluctuations with small fluctuations of less than 10% other than instantaneous voltage drops, such as waveform distortion, flicker, etc.

Therefore, an object of the present invention is to provide a series compensation type voltage fluctuation compensator that can not only compensate for voltage fluctuations with a large fluctuation range but also compensate for voltage fluctuations with a small fluctuation range.

[Means for solving problems]

The series compensation type voltage fluctuation compensator of the present invention has a compensation power supply that constantly generates a compensation voltage according to the voltage fluctuation of the grid side power supply inserted in series between the grid side power supply and the load with additive polarity. It is characterized by

[Effect]

According to the configuration of the present invention, a compensation power supply that constantly generates a compensation voltage corresponding to the voltage fluctuation of the grid side power supply is inserted in series with the addition polarity in the power supply path from the grid side power supply to the load. A voltage that is the sum of the voltage of the grid-side power supply and the compensation voltage will be applied to the load. At this time, a voltage corresponding to the variation in the voltage of the grid-side power supply is outputted from the compensation power supply as a compensation voltage, and the variation in the voltage of the grid-side power supply is compensated by the variation in the compensation voltage. Therefore, it is possible not only to compensate for voltage fluctuations with a large fluctuation range such as instantaneous voltage drop of the power supply on the grid side, but also to compensate for voltage fluctuations with a small fluctuation range such as waveform distortion and flicker.

〔Example〕

An embodiment of the present invention will be described based on FIGS. 1 to 3. As shown in FIG. 1, this series compensation type voltage fluctuation compensator connects a compensation power supply 10 that constantly generates a compensation voltage vH according to the fluctuation of the voltage V of a grid-side power supply 1 to a grid-side power supply 1 and a load. It is characterized in that it is inserted in series with addition polarity between it and 7.

This series compensation type voltage fluctuation compensator will be explained in detail below. This series compensation type voltage fluctuation compensator is a system-side power supply 1
A rectifier circuit 2 that obtains DC power by full-wave rectifying the voltage V, , an inverter 4 that is supplied with power from this electrolytic capacitor 3 and is constantly operated to constantly generate a compensation voltage ■1 for compensating for voltage fluctuations in the voltage V of the grid side power supply 1, and an output voltage ■1 of this inverter 4. The main component is a coupling transformer 5 for series compensation in which a voltage is applied to the primary winding and a secondary winding is inserted between the grid-side type rAl and the load 7.

Note that the inverter 4 uses the voltage ■ of the grid side power supply 1.

It is controlled by a control circuit 8 that detects voltage fluctuations. Further, the capacitance of the electrolytic capacitor 3 is set so that it can store compensation power capable of compensating for an instantaneous voltage drop that has a drop width of 50% or more and a duration of 0.1 seconds or more. Further, the turns ratio of the coupling transformer 5 is set to 1:1 or another value, and in the case of 1:1, the compensation voltage v1 and the compensation voltage ■□ become equal.

With the configuration described above, this series compensation type voltage fluctuation compensator performs full-wave rectification of the voltage V of the system side type B1 in the rectifier circuit 2, and uses the output of the rectifier circuit 2 to connect the electrolytic capacitor for power storage for compensation. 3 is charged, and the electrolytic capacitor 3 supplies power to the inverter 4, so that the inverter 4 constantly generates a compensation voltage ■1 corresponding to the fluctuation of the voltage ■ of the grid side power supply 1, and this compensation voltage ■1 is applied to the coupling transformer. 5 to the voltage V of the power supply 1 on the grid side and applied to the load 7.

As a result, when an instantaneous voltage drop occurs in the grid-side power supply l and the voltage of the grid-side power supply 1 instantaneously drops by more than 10%, for example, the DC power accumulated in the electrolytic capacitor 3 The inverter 4 operates to generate a compensation voltage ■1 corresponding to the drop in the voltage VS of the grid side power supply 1, and this compensation voltage v1 is converted to the voltage ■ of the grid side power supply 1 through the coupling transformer 5 for series compensation. The sum will be added and applied to the load 7. At this time, the voltage corresponding to the variation in the voltage V of the grid side power supply 1 is outputted from the inverter 4 as the compensation voltage ■1, and the variation in the voltage V of the grid side power supply 1 is the compensation voltage V
, will be compensated for by the fluctuation of . Therefore, the load voltage vL across the load 7 is always constant regardless of the instantaneous voltage drop in the voltage V of the power supply l on the grid side.

In addition, even when voltage fluctuations of 10% or less, such as waveform distortion and flicker, occur in the voltage V of the grid-side power supply 1, the DC power stored in the electrolytic capacitor 3 is used to connect the inverter 4 as described above. operates and the voltage v of the grid side power supply l
A compensation voltage v1 corresponding to the decrease in s is generated, and this compensation voltage v1 is added to the voltage V of the grid side power supply 1 via the series compensation coupling transformer 5 and applied to the load 7, With the same effect as above, the voltage of the system side type AL is ■.

The load voltage vL across the load 7 is always constant regardless of the small voltage fluctuation.

Here, the specific configuration and operation of the control circuit 8 will be explained based on FIG. 2. This control circuit 8 is connected to the grid side power supply 1
The voltage V, of the voltage V, of the voltage transformer 1) is detected by the voltage transformer 1), and the phase synchronization circuit 12 detects the voltage V of the power supply l on the grid side based on the secondary voltage v,1 of the voltage transformer 1).

A synchronization signal synchronized with is created, and based on this synchronization signal, the reference sine wave generation circuit 13 generates a reference sine wave voltage vR with an amplitude corresponding to the normal value of the voltage V of the power supply l on the grid side. It has become. This reference sine wave voltage vR becomes a target value of the voltage to be applied to the load 7.

Then, the subtracter 14 calculates the difference between the reference sine wave voltage vR and the secondary voltage VSt, and the obtained difference voltage VD is applied to the pulse width modulation circuit 15.
5 is compared with, for example, a triangular wave, and the pulse width modulation circuit 15 outputs a differential voltage ■.

A pulse width modulated voltage V, corresponding to , is output, and this pulse width modulated voltage V, is applied to the base drive circuit (not shown) of the inverter 4. As a result, a difference voltage (■) between the reference sine wave voltage vR from the inverter 4 and the secondary voltage VSI of the potential transformer 1). Compensation voltage v1 corresponding to
, that is, a compensation voltage v1 corresponding to the variation in the voltage V of the grid side power supply 1 is output, and this compensation voltage v1 is added to the voltage V of the grid side power supply 1 via the coupling transformer 5 and applied to the load 7. The load voltage ■L that is applied and appears across the load 7 has a value corresponding to the reference sine wave voltage vR.

FIG. 3 is a voltage waveform diagram showing voltage compensation by the series compensation type voltage fluctuation compensator.

The solid line in FIG. 3 1al shows a waveform diagram of the voltage (2) of the grid-side power supply 1 when slight voltage fluctuations and instantaneous voltage drops occur. In the same figure (al), a slight voltage fluctuation other than the instantaneous voltage drop occurs between time t1 and t2 with a fluctuation width of 10% or less, and an instantaneous voltage drop with a fluctuation width of more than 10% occurs after time t2. The broken lines in 1 ml of the same figure show the waveforms of the voltages ■ and ' during normal conditions.

3) shows a waveform diagram of the compensation voltage 1 outputted from the inverter 4 with respect to the fluctuation of the voltage 2 shown in FIG. 3 Tal. In the same figure (bl), between times t1 and t2, the compensation voltage ■
1 is output, and after time t2, the inverter 4 outputs a compensation voltage V according to the instantaneous voltage drop.

is being output.

FIG. 3 (cl shows a waveform diagram of load voltage 1 applied to load 7. In FIG. This indicates that the load voltage vL is normal regardless of the voltage fluctuation of the power supply 1 on the grid side.

The series compensation type voltage fluctuation compensator of this embodiment constantly generates a compensation voltage VI from the inverter 4 corresponding to the fluctuation of the voltage V of the system bias a1, and transmits this compensation voltage v1 via the coupling transformer 5 to the system bias Since the voltage V of the grid side power source l and the compensation voltage vH are added to the voltage vL of the grid side power source l and applied to the load 7, the voltage vL that is the sum of the voltage V of the grid side power supply l and the compensation voltage vH is applied to the load 7. A voltage corresponding to the variation in the voltage V is outputted from the inverter 4 as the compensation voltage v1, and a variation in the voltage v3 of the grid side power supply l is the compensation voltage v.
This will be compensated for by a change of 1. Therefore, it not only compensates for large voltage fluctuations such as instantaneous voltage drops in the grid-side power supply l, but also compensates for waveform distortion.

It is also possible to compensate for voltage fluctuations with a small fluctuation range such as flicker.

In addition, the series compensation type voltage fluctuation compensator of this embodiment requires a capacity equivalent to the load rating as the instantaneous maximum rating, but the fluctuation range of continuously occurring minute voltage fluctuations is at most 10% or less. Therefore, the continuous rating may be small. Therefore, it is possible to compensate for voltage fluctuations, including instantaneous voltage drops, while significantly reducing device capacity and operational loss.

In the above embodiment, a coupling transformer 5 is provided in order to add the compensation voltage vI output from the inverter 4 to the voltage V of the grid side power supply 1, but the connection between the grid side power supply l and the rectifier circuit 2 is If an insulated transformer is provided between them, the above coupling transformer 5 can be omitted.

〔Effect of the invention〕

According to the series compensation type voltage fluctuation compensator of the present invention, the compensation power supply that constantly generates a compensation voltage corresponding to the fluctuation in the voltage of the grid side power supply is connected to the adding polarity in the power supply path from the grid side power supply to the load. Since it is inserted in series, the voltage that is the sum of the voltage of the power supply on the grid side and the compensation voltage will be applied to the load.
Since the voltage corresponding to the variation in the voltage of the grid-side power supply is outputted from the compensation power supply as the compensation voltage, the variation in the voltage of the grid-side power supply is compensated by the variation in the compensation voltage.

Therefore, it is possible not only to compensate for voltage fluctuations with a large fluctuation range such as instantaneous voltage drop of the power supply on the grid side, but also to compensate for voltage fluctuations with a small fluctuation range such as waveform distortion and flicker.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.
Figure 2 is a block diagram showing the specific configuration of the main parts in Figure 1, Figure 3 is a waveform diagram of each part in Figure 1, Figure 4 is a block diagram showing the configuration of a conventional example, and Figure 5 is the It is a waveform chart of each part of a figure. DESCRIPTION OF SYMBOLS 1... Grid side power supply, 2... Rectifier circuit, 3... Electrolytic capacitor, 4... Inverter, 5... Coupling transformer, 7... Load, 8... Control circuit, lO. ... Compensation power supply Figure 1 Figure 4

Claims (2)

[Claims] (1) A series compensated voltage characterized in that a compensating power supply that constantly generates a compensation voltage according to voltage fluctuations of the grid side power supply is inserted in series with addition polarity between the grid side power supply and the load. Fluctuation compensator. (2) The compensation power supply includes a rectifier circuit that rectifies the voltage of the grid-side power supply, and is charged with the output of the rectification circuit, and has a duration of 0 if the voltage of the grid-side power supply decreases by 50% or more.
．． a DC capacitor that stores enough energy to supply power to the load for one second or more; an inverter that is supplied with power from the DC capacitor and constantly generates a compensation voltage corresponding to the voltage fluctuation of the grid side power supply; A coupling transformer having a winding to which a compensation voltage outputted from the inverter is applied and a secondary winding inserted in series in a power supply path from the system side power supply to the load. ) The series compensation type voltage fluctuation compensator described in item 2.