JP3349102B2 - Test method of electronic watt-hour meter and electronic watt-hour meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a test method for determining whether or not the number of power amount pulses generated by an electronic watt-hour meter at a test time is as specified, and a method suitable for performing this test. It relates to an electronic watt-hour meter.

[0002]

2. Description of the Related Art FIG. 5 shows an equivalent circuit configuration of a conventional LSI for an electronic watt-hour meter. 1 is an A / D converter for A / D converting the voltage v to be measured, 2 is an A / D converter for A / D converting the current i to be measured, 3 is a multiplier, 4 is a cumulative adder, 5 Is a pulse generator, 6 is an oscillator, and 7 is a frequency divider for outputting a sampling signal.

A / D converters 1 and 2 convert an analog value voltage v and an analog value current i into a digital voltage signal and a digital current signal, respectively, and these signals are multiplied by a multiplier 3 to obtain a digital value signal. Converted to power data. The cumulative adder 4 cumulatively adds the power data from the multiplier 3 and the cumulative added value is equal to or greater than a predetermined output reference value (a value of power data corresponding to power corresponding to one power amount pulse). , The pulse generator 5
A command is issued to generate power pulses, and power data corresponding to one power pulse is subtracted from the accumulated value.

The sampling signal of the frequency divider 7 is supplied to A / D converters 1 and 2 and the accumulator 4.

The time required for the cumulative addition value of the cumulative adder 4 to become greater than the output reference value from 0 becomes shorter as the instantaneous power becomes larger. Therefore, the output frequency of the pulse generation command becomes higher as the instantaneous power becomes larger. As a result, an electric energy pulse train corresponding to the electric power value is output from the pulse generator 5. The electric energy pulse is used for the electric energy display and the accuracy test of the electronic wattmeter.

[0006] Since recent electronic watt-hour meters frequently use digital circuits, the digital circuits tend to be integrated in LSIs and the like. In the shipment test of the LSI for the electronic watt-hour meter, the accuracy is confirmed using the electric energy pulse train.

[0007]

FIG. 6 shows the frequencies of the voltage v and the current i input to the A / D converters 1 and 2 in FIG.
(A) When the commercial frequency is used as shown in (b),
The analog value of the electric power vi is as shown in FIG. 6C. At this time, the electric energy pulse output from the pulse generator 5 is as shown in FIG.
As shown in (d), the pulse becomes sparse and dense within one cycle of the commercial frequency.

When a shipping test of an electronic watt-hour meter LSI is to be performed in a short time by using such a watt-hour pulse train, the watt-hour pulse train is sparse and dense within one cycle of a commercial frequency. In addition, there is a problem in that the number of pulse outputs during the test time varies, and as a result, the measurement accuracy deteriorates. For this reason, in order to reduce the influence of the sparse and dense power amount pulse train, it is necessary to take about 10 seconds for the test time per LSI for the electronic watt-hour meter. Therefore, when conducting a shipping test of a large number of products, a long test time is required, which hinders a reduction in the price of the products and a rapid production. (Object of the Invention) It is an object of the present invention to provide a test method and an electronic watt-hour meter for an electronic watt-hour meter capable of reducing the test time.

[0009]

To achieve the above object, according to the present invention, a digital value of instantaneous power is obtained based on a sampling signal, and a power amount pulse corresponding to the power amount is electronically generated. This is a method of testing the number of electric energy pulses during the test time of an electronic watt-hour meter that is generated periodically.The test voltage and test current input as measurement targets during the test are set higher than the commercial frequency, Further, the frequency of the sampling signal is set to be higher in proportion to an increase in the frequency of the test voltage and the test current.

According to another aspect of the present invention, a digital value of an instantaneous power is obtained based on a sampling signal, and a power pulse corresponding to the power is electronically generated. In the electronic watt-hour meter, while generating a sampling signal for a steady state, a sampling signal generating means for generating a sampling signal for a test that is higher than the frequency of the sampling signal for a steady state, Setting means for selecting a sampling signal for regular use and selecting a sampling signal for the test at the time of a test.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an LSI for a digital multiplication type single-phase electronic watt-hour meter for implementing the test method of the present invention.
FIG. 2 is a diagram illustrating one embodiment of the equivalent circuit configuration of FIG. Note that, in this figure, a measurement portion for counting a power amount pulse, which is a portion other than the LSI, a display portion for displaying the power amount, and the like are omitted.

1 to 7 are the same as those shown in FIG. 5; 1 is an A / D converter for A / D converting a voltage v to be measured; and 2 is an A / D converter for a current i to be measured. A / D converter, 3 is a multiplier, 4 is a cumulative adder, 5 is a pulse generator,
Reference numeral 6 denotes an oscillator, and reference numeral 7 denotes a frequency divider which constitutes sampling signal generating means for outputting a sampling signal. However, the frequency divider 7 generates the stationary sampling signal S ₁ and the test sampling signal S ₂ by dividing the sampling source signal from the oscillator 6. Reference numeral 8 denotes a setting device which constitutes a setting means, and selects _one of a stationary sampling signal S ₁ and a test sampling signal S ₂ by operating an operation member 9 including a switch or a microcomputer. It is supplied to the D converters 1 and 2 and the accumulator 4.

A portion surrounded by a dotted line in FIG. 1 is included in the electronic power meter LSI 10. The setting device 8 does not have to be included in the electronic watt-hour meter LSI 10 and may be any as long as it is included inside the electronic watt-hour meter. The operation member 9 is provided outside the electronic wattmeter LSI 10 and is provided inside or outside the electronic wattmeter.

The frequency of the stationary sampling signal S ₁ is set to a conventional sampling frequency suitable for the commercial frequency of the voltage v and the current i input to the A / D converters 1 and 2 in the stationary state. The frequency of the test sampling signal S ₂ is higher than the frequency of the stationary sampling signal S ₁ , for example, set to n times, and is input to the A / D converters 1 and 2 as a measurement target during the test. The frequency of the test voltage v and the test current i is also higher than the commercial frequency at the same magnification as that of the sampling signal, for example, set to n times.

In a steady state, the setting unit 8 selects the sampling signal S ₁ in the steady state, and the sampling signal is set to S ₁ by this.

The operation in the steady state is the same as that in FIG.
The A / D converters 1 and 2 convert the analog value voltage v and the analog value current i into a digital voltage signal and a digital current signal, respectively. These signals are multiplied by a multiplier 3 to obtain digital value power data. Is converted. The cumulative adder 4 cumulatively adds the power data from the multiplier 3 and the cumulative added value is equal to or greater than a predetermined output reference value (a value of power data corresponding to power corresponding to one power amount pulse). Then, the pulse generator 5 is instructed to generate one electric energy pulse, and electric power data corresponding to one electric energy pulse is subtracted from the accumulated value. The pulse generator 5 outputs an electric energy pulse, which is counted by a subsequent circuit, displayed as an electric energy, and output to the outside of the electric energy meter.

At the time of a test, the setting device 8 selects a test sampling signal S ₂ by operating the operation member 9.
This sampling signal is set to S _2.

At the time of the test, the A / D converters 1 and 2 apply a test voltage v and a test current i having a frequency n times the commercial frequency to the A / D converters 1 and 2.
Are input and converted into a digital voltage signal and a digital current signal, respectively. These digital signals are multiplied by the multiplier 3 and converted into digital power data. The cumulative adder 4 cumulatively adds the power data from the multiplier 3 and, when the cumulative added value becomes equal to or greater than a predetermined output reference value, instructs the pulse generator 5 to generate one power amount pulse. , The power data corresponding to one power pulse is subtracted from the accumulated value. The pulse generator 5 outputs an electric energy pulse.

The magnification of the test sampling signal ₂ with respect to the stationary sampling signal S _{1 is,} for example, twice (n =
If it is set to 2), test voltage v, test current i
Is also set to twice the commercial frequency, and FIG.
(B). The analog value of power vi is shown in FIG.
2C. At this time, the electric energy pulse output from the pulse generator 5 is as shown in FIG. 2D, and the pulse is sparse and dense within one cycle of the test voltage v and the test current i.

When the sampling frequency is doubled, the frequency of the test voltage v and the test current i is also twice the commercial frequency, so that the number of samples per cycle of the test voltage v and the test current i is the same. . The output reference value of the accumulator 4 is not changed. Therefore, the number of power amount pulses in one cycle of the test voltage v and the test current i is the same as the case where the voltage v and the current i are at the commercial frequency regardless of whether the sampling frequency is doubled or multiplied. The number is the same. One cycle of the test voltage v and the test current i is 1
/ 2 (that is, 1 / n).
(1 / n).

As the A / D converters 1 and 2 shown in FIG. 1, those having ΔΣ modulators 11 and 12 and digital filters 13 and 14 as shown in FIG. 3 can be used.

As shown in FIG. 4, the setting device 8 is located between the oscillator 6 and the frequency divider 7, and by operating the operating member 9, the setting device 8 is connected to the oscillator 6 and the LSI for the electronic watt-hour meter. The output of the frequency divider 7 can be set to _one of the sampling signals S ₁ and S ₂ by selecting any one of the external oscillators 15 located outside.

In FIGS. 1 _, 3 and 4, the electronic power of the digital multiplication system in which digital multiplication is performed using an A / D converter for converting the voltage v and the current i to be measured into digital values. I explained the test method applied to the meter.
The present invention can be applied to an analog multiplication-type electronic watt-hour meter that performs analog multiplication of the current i and the voltage v and converts the analog multiplication value into a digital value.

[0024]

As described above, according to the first or second aspect of the present invention, the test time can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of an equivalent circuit configuration of a digital multiplication type electronic watt-hour LSI implementing the present invention.

FIG. 2 is a diagram showing a signal waveform in the electronic watt-hour meter LSI of FIG. 1;

FIG. 3 is a diagram showing another embodiment of an equivalent circuit configuration of a digital multiplication type electronic watt-hour LSI implementing the present invention.

FIG. 4 is a diagram showing another embodiment of an equivalent circuit configuration of a digital multiplication type electronic watt-hour LSI implementing the present invention.

FIG. 5 shows a conventional digital multiplication type electric wattmeter L
FIG. 3 is a diagram illustrating an equivalent circuit configuration of an SI.

FIG. 6 is a diagram showing a signal waveform in the electronic watt-hour meter LSI of FIG. 5;

[Explanation of symbols]

 1, 2 A / D converter 3 Multiplier 4 Cumulative adder 5 Pulse generator 6 Oscillator 7 Divider (sampling signal generating means) 8 Setting device (Setting device) 9 Operating member 10 Electronic power meter LSI 11,12 ΔΣ modulator 13,14 Digital filter 15 External oscillator

Continuation of the front page (72) Inventor Naoto Kawashima 743-6-401, Soyodo-cho, Kohoku-ku, Yokohama-shi, Kanagawa Prefecture (56) References JP-A-5-133987 (JP, A) . ^7, DB name) G01R 21/00 - 22/00 130 G01R 11/00 - 11/66 G01R 35/00 - 35/04 G01R 31/28 - 31/3193 H03M 1/10

Claims (2)

(57) [Claims] 1. An electronic watt-hour meter that obtains a digital value of instantaneous power based on a sampling signal and electronically generates a power amount pulse corresponding to a power amount, tests the number of power amount pulses during a test time. A test voltage input as a measurement target during a test, the frequency of the test current is set higher than the commercial frequency, and the frequency of the sampling signal is also proportional to the increase in the frequency of the test voltage, test current A test method for an electronic watt-hour meter, characterized in that it is set at a high value. 2. An electronic watt-hour meter that obtains a digital value of instantaneous power based on a sampling signal and electronically generates a power amount pulse corresponding to the power amount, generates a sampling signal for a steady state, and A sampling signal generating means for generating a sampling signal for a test higher than the frequency of the sampling signal for a steady state, and selecting the sampling signal for the steady state as a sampling signal in a steady state, An electronic watt-hour meter having setting means for selecting a sampling signal.