JP6584273B2 - Measuring device - Google Patents

Description

  The present invention relates to a measuring device for measuring the amount of power generated by a distributed power source.

  The amount of power generated by a distributed power source such as a solar cell varies greatly depending on the time of day and the weather. For this reason, it is assumed that the power generation status is grasped and managed by providing a measuring device that measures the amount of power generated from each solar cell string and transmits the measurement information to the outside (Patent Document 1).

  The measuring device has a measuring device main body connected to the solar cell string and a current sensor connected to the measuring device main body via a communication line, and measurement information by the current sensor is measured as a voltage signal. It is returned to the calculation unit in the body, and the calculation unit derives a measured current value based on the voltage value and outputs the information to the external device as described above.

  Here, as shown in FIG. 4, since the current sensor 8 is configured by a Hall element, the current sensor 8 is driven by being supplied with electric power from the solar cell string 1. Driven by the applied voltage. A rated voltage value is determined for the voltage output from the power supply unit. However, some errors occur in the actually output actually measured voltage due to individual differences in the power supply units. For this reason, an error also occurs in the actually measured voltage input to the current sensor, and this error also affects the measurement value input to the arithmetic unit and the external device. As a result, erroneous measurement information is transmitted to the subsequent stage. It will end up.

  In order to solve this problem, a method of correcting erroneous information input to the arithmetic unit and outputting it as a correct numerical value can be considered. Specifically, as shown in FIG. 5, before the measurement apparatus is shipped, the maximum and minimum values of the measurement current are passed in advance, and the current values and the voltage values (a, b) output from the current sensors are stored. In this case, the measurement information can be corrected to an ideal value represented by a dotted line in the figure by the calculation unit.

  However, in the above method, since it is necessary to make adjustments for each combination of the measuring device main body and each current sensor that is actually installed, for example, even when only the current sensor fails, the measuring device main body and the newly prepared current sensor are There is a problem that it takes time and cost because it must be adjusted again by flowing the maximum and minimum values of the measurement current by combining them again at the installation site.

JP2011-119579

  An object of the present invention is to solve the above-described conventional problems and to provide a measuring apparatus that eliminates the need for re-adjustment that takes time when replacing a current sensor.

The present invention made to solve the above problems is a measuring device comprising a measuring device main body connected to a distributed power source, and a current sensor connected to the measuring device main body, the measuring device main body comprising: A power supply unit that converts the output from the distributed power supply and supplies power to the current sensor, a storage unit that stores an actual voltage and a rated voltage that the power supply unit outputs to the current sensor, and a voltage returned from the current sensor A calculation unit that reads a signal as an actual measurement current value, and further calculates the G (gain) by dividing the actual measurement voltage by the rated voltage, and divides the actual measurement current value input to the calculation unit by this G. Thus, a first processing function for correcting the measured current value is provided.

  According to a second aspect of the present invention, in the measurement apparatus according to the first aspect, the calculation unit outputs a voltage signal returned from the current sensor to 0 A when the measurement current is 0 A after the first processing function is executed. The second processing function for adjusting so as to be determined is provided.

  According to the measuring device according to the present invention, the measuring device main body converts the output from the distributed power source and supplies power to the current sensor, and the actual voltage and the rated voltage output from the power source to the current sensor. A storage unit that stores the voltage signal returned from the current sensor as an actual current value; and the arithmetic unit further corrects the actual current value based on a ratio between the actual voltage and the rated voltage. One processing function was provided. By executing this first processing function, G (gain) is obtained from the actually measured voltage / rated voltage, and then the actually measured current value input to the calculation unit is divided by this G to represent a current sensor expressed as a linear function. It is possible to correct the relationship between the output voltage (y) and the measurement current (x) as having the same slope as the ideal value. Accordingly, since it is not necessary to correct the current value by actually measuring each current sensor, readjustment is not necessary when the current sensor is replaced.

  According to the second aspect of the present invention, the second processing function for adjusting the voltage signal returned from the current sensor to be determined as 0 A when the measured current is 0 A after the first processing function is executed, the arithmetic unit To prepare for. By executing this second processing function, the relationship between the output voltage (y) from the current sensor and the measured current (x) is corrected so as to have the same zero intercept as the ideal value, and the output voltage due to the individual difference of the current sensor. Even if an error occurs, an approximate value that substantially matches the ideal value can be obtained.

1 is an overall view of a solar power generation system. It is a figure which shows the measuring device of this invention. It is a figure which shows the correction method by this invention. It is a figure which shows the connection of a measuring device main body and a current sensor. It is a figure which shows the conventional correction method.

Preferred embodiments of the present invention are shown below.
As shown in FIG. 1, a plurality of solar cell strings 1 that are distributed power sources are connected in parallel in each connection box 2. And these connection boxes 2 are arranged in a plurality of stages and connected in parallel to collect power in the current collection box 3. Further, a power conditioner 4 and a cubicle 5 are provided at the subsequent stage of the current collection box 3.

  A measuring device 6 for measuring the amount of power generated from the solar cell string 1 is provided inside each connection box 2. The measuring device 6 also includes an external device 9 for transmitting measurement information to the subsequent current collection box 3 and the like. Further, the measurement information may be integrated with information output from the power conditioner 4 and aggregated in the cubicle 5.

The present invention relates to the measuring device 6, and details thereof are shown in FIG.
Although 1 is a solar cell string, it can also be various distributed power supplies whose output immediately after activation is weak, and may be, for example, a wind power generator, a gas generator, a storage battery, or the like. The measuring device 6 includes a measuring device main body 7 connected to the solar cell string 1, a current sensor 8 connected to the measuring device main body 7 via the communication line 10, and the external device 9 described above. The current sensor 8 is constituted by a Hall element. Inside the measuring device body 7, a converter 11 that converts a direct current output from the solar cell string 1 into a constant voltage, and a voltage output from the solar cell string 1 as well as the converter 11 are converted. And a power supply unit 12 for supplying electric power to the current sensor 8. Further, the measuring device body 7 includes a storage unit 13 that stores the actual voltage and the rated voltage that the power supply unit 12 outputs to the current sensor 8, and a calculation unit 14 that reads a voltage signal returned from the current sensor 8 as an actual current value. Built-in.

In addition to supplying power to the external device 9, the converter 11 converts voltage through the power supply unit 12 and supplies power to the arithmetic unit 14 and the like.
The external device 9 communicates the measured power generation amount to the outside wirelessly or the like, but may be another device that communicates by wire. With the above configuration, the current value measured by the current sensor 8 is returned to the calculation unit 14, and the measurement information processed in the calculation unit 14 is sent to the external device 9, so that it is output from the solar cell string 1. It is possible to obtain information on the amount of power generated.

  Here, the calculation unit 14 is provided with a first processing function for correcting the measured current value based on the ratio between the measured voltage and the rated voltage output from the power supply unit 12 to the current sensor 8. More specifically, based on the measured voltage and rated voltage information stored in the storage unit 13, the measured voltage is first divided by the rated voltage to obtain G (gain). Next, by dividing the actually measured current value input to the calculation unit 14 by this G, as shown by an arrow c in FIG. 3, the output voltage (y) from the current sensor expressed as a linear function and the measured current ( x) can be corrected as having the same slope as the ideal value. Therefore, since it is not necessary to correct the current value by actually measuring each current sensor 8, readjustment is not necessary when the current sensor 8 is replaced.

  Further, the calculation unit 14 is assumed to have a second processing function. Specifically, after the first processing function is executed, the voltage signal returned from the current sensor 8 is adjusted to be determined as 0A when the measured current is 0A. It was. By executing this second processing function, as indicated by an arrow d in FIG. 3, the relationship between the output voltage (y) from the current sensor 8 and the measured current (x) becomes 0 intercept, which is the same as the ideal value. Thus, even if there is an error in the output voltage due to individual differences of the current sensors 8, an approximate value that substantially matches the ideal value can be obtained. Note that this second processing function is executed by pressing a reset button or the like provided on the measurement apparatus main body 7.

  Further, as shown in FIG. 2, a delay circuit 15 is arranged between the converter 11 and the external device 9. The delay circuit 15 monitors the potential connected to the converter 11 and closes the electrical circuit connected to the external device 9 when the potential exceeds a predetermined value. Thereby, since the timing at which the transient current flows into the converter 11 and the timing at which the transient current flows into the external device 9 can be shifted, the transient current flowing into the converter 11 can be suppressed within the allowable current value. It is supposed to be.

DESCRIPTION OF SYMBOLS 1 Solar cell string 2 Connection box 3 Current collection box 4 Power conditioner 5 Cubicle 6 Measuring device 7 Measuring device main body 8 Current sensor 9 External device 10 Communication line 11 Converter 12 Power supply part 13 Memory | storage part 14 Calculation part 15 Delay circuit

Claims (2)

A measuring device connected to a distributed power source;
A measuring device comprising a current sensor connected to the measuring device body,
The measuring device body is
A power supply unit that converts the output from the distributed power supply and supplies power to the current sensor;
A storage unit for storing the measured voltage and the rated voltage output by the power supply unit to the current sensor;
A calculation unit that reads a voltage signal returned from the current sensor as an actual measurement current value;
Furthermore, this calculation unit
A first processing function for correcting the actual measurement current value by dividing the actual measurement voltage by the rated voltage to obtain G (gain) and dividing the actual measurement current value input to the calculation unit by the G is provided. A measuring device. The computing unit is
After the first processing function is executed,
The measuring apparatus according to claim 1, further comprising a second processing function that adjusts the voltage signal returned from the current sensor to be determined as 0 A when the measurement current is 0 A.