JP3221595B2 - AC electricity-DC voltage converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC electrical-DC voltage converter for converting an electrical quantity such as an average value, an effective value, and a power value of an AC signal into a DC voltage.

[0002]

2. Description of the Related Art Conventionally, an AC electric quantity for converting an electric quantity such as an average value, an effective value and an electric power value of an AC signal into a DC voltage is used.
2. Description of the Related Art A direct-current voltage converter is as shown in FIG.
That is, the AC signals S11 to S15 are input to the converters 21 to 25, respectively, and the outputs of the averaging capacitors C11 to C15 connected to the converters are switched by the multiplexer 26. Was output as

[0003]

However, the conventional AC electricity-to-DC voltage converter requires a converter for each input circuit. Therefore, as the number of input circuits increases, the number of converters increases, and the number of converters increases accordingly. However, there is a disadvantage that the size of the device increases and the manufacturing cost increases.

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, an object of the present invention is to provide an AC electricity-DC voltage converter capable of reducing the size of the device and reducing the manufacturing cost. The configuration is such that a multiplexer for sequentially inputting a plurality of AC signals to the AC electricity-DC voltage converter, an averaging capacitor for averaging the processed signals in the middle of the conversion, and synchronization with switching of the input AC signal. And a demultiplexer for sequentially inputting the processing signal to each of the averaging capacitors.

[0005]

The multiplexer provided at the input and the demultiplexer provided at the converter are sequentially switched in synchronism, and after one round, they are again in the initial connection state, and this is repeated. In this process, the averaging capacitors are charged to a DC potential proportional to the quantity of electricity of the corresponding input signal. However, during the period when the demultiplexer is off (while the other capacitors are on), the potential just before the off is maintained. , During the ON period, the potential changes according to the input signal.

As a result, a DC voltage proportional to the electric quantity of the input signal is sequentially output from the AC electric quantity-DC voltage converter, and further input to the latch circuit as digital data via an A / D converter. The digital data from the A / D converter is taken into the latch circuit at the timing immediately before the switching of the multiplexer and the demultiplexer, so that the latest data of the electric quantity of the AC signal is stored in the latch circuit as a digital value. This value is displayed on each display device connected to the latch circuit.

[0007]

FIG. 1 shows an embodiment of an AC electricity-DC voltage converter according to the present invention. The present invention will be described below with reference to the drawings.

The AC electricity-DC voltage converter 1 converts an effective value of an AC signal into a DC voltage, and a multiplexer 2 for switching AC signals S1 to S5 and an RMS-D
The A / D converter 5 includes a C converter 3, a demultiplexer 4, and averaging capacitors C1 to C5.
Latch circuits 6, 7, 8, 9, 10 and display devices 11, 1
2, 13, 14, and 15 are connected. Also RMS-D
The C converter 3 includes an absolute value circuit 16 and a square division circuit 1
7, a converter 18, and an output circuit 19, and the converter 1
8 includes a demultiplexer 4 and averaging capacitors C1 to C1.
C5 is connected.

The multiplexer 2 provided at the input and the demultiplexer 4 provided at the converter 18 are sequentially switched in synchronization. Capacitor C1 when AC signal S1 is input
However, the capacitor C2 when the AC signal S2 is input, the capacitor C3 when the AC signal S3 is input, the capacitor C4 when the AC signal S4 is input, and the capacitor C4 when the AC signal S5 is input.
5 are respectively connected to the converter 18, and then the S1 input C1
The connection state is established and this is repeated. In this process, the averaging capacitors C1 to C5 connected to the converter 18 are each charged to a DC potential proportional to the effective value of the corresponding input signal, while the demultiplexer 4 is off (when the other capacitors are on). During the on period, the potential changes to a potential corresponding to the input signal during the on period.

As a result, five kinds of DC voltages proportional to the effective value of the input signal are sequentially output from the output circuit 19 in accordance with the five kinds of input signals.
The digital data is input to the latch circuits 6 to 10 as various types of digital data. The latch circuit n corresponds to the AC signal Sn and the averaging capacitor Cn, and the AC electricity-DC voltage converter 1
A read pulse for reading data is applied immediately before the switching of the multiplexer 2 and the demultiplexer 4 of the first embodiment, so that the effective values of the AC signals S1 to S5 are stored as digital values in the latch circuits 6 to 10, respectively. This value is stored in each of the display devices 11 to 1 connected to the latch circuit.
5 is displayed.

For example, if the multiplexer 2 and the demultiplexer 4 are switched every 0.2 seconds, the number of input circuits is 5, so that the digital effective value for 5 signals for updating the display value every 1 second A meter can be realized.

Switching the averaging capacitor and using it requires a certain time for charging and discharging of the averaging capacitor. If a plurality of electric quantities are converted by switching the input within this time, an extremely large error will occur. This is because it cannot be realized with one capacitor because it is large.

Although the present embodiment has been described with respect to an AC electric quantity-DC voltage converter for converting an electric quantity of an effective value of an AC signal into a DC voltage, the present invention is not limited to this embodiment. Values, power values, etc., can be changed as appropriate as long as they are AC signals.

Further, the number of input circuits is not limited to the five circuits of the present embodiment, but can be appropriately changed without departing from the gist of the present invention.

[0015]

As described above, the AC electricity-DC voltage converter of the present invention comprises a multiplexer for sequentially inputting a plurality of AC signals and an averaging capacitor for averaging the processed signals during the conversion. And a demultiplexer for sequentially inputting the processed signal to each of the averaging capacitors in synchronization with the switching of the input AC signal, so that the device can be configured with one converter. There is an effect that the size can be reduced and the manufacturing cost can be reduced.

In the present invention, even if the signal level difference between the input signals is large, if the signal changes relatively slowly, the same measurement accuracy as in the prior art can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of an AC electricity-DC voltage converter according to the present invention.

FIG. 2 is a block diagram of a conventional AC electricity-DC voltage converter.

[Explanation of symbols]

1 ... AC electricity-DC voltage converter, 2 ... Mux, 3 ... RMS-DC converter, 4 ...
・ Demultiplexer, 5 ... A / D converter, 6,
7, 8, 9, 10 ... Latch circuit, 11, 12, 1
3, 14, 15 ... display device, 16 ... absolute value circuit, 17 ... square division circuit, 18 ... converter, 19
... Output circuits, S1, S2, S3, S4, S5 ...
AC signal, C1, C2, C3, C4, C5 ... Averaging capacitor.

Claims (1)

(57) [Claims] 1. A converter for converting an AC electric quantity into a DC voltage, comprising: a multiplexer for sequentially inputting a plurality of AC signals to the converter; and a multiplexer for averaging a processing signal during the conversion. Characterized by comprising: an averaging capacitor, and a demultiplexer for sequentially inputting the processing signal to each of the averaging capacitors in synchronization with switching of an input AC signal. .