KR101040642B1 - Power supply device using solar cell module - Google Patents

Abstract

The present invention is a solar cell module for generating direct current power by converting solar energy into electrical energy; A voltage detection device for measuring an open voltage, which is an output voltage of the solar cell module; An inverter device for converting DC power into AC power; A controller including a CPU for performing a control operation of the inverter device, a high speed communication unit, and a reference voltage source for providing an initial reference voltage; A transformer for boosting the voltage of AC power; A grid voltage current detection device for detecting grid voltage signals of a commercial power system; And an associated connection device provided between the transformer and the commercial power system to serve as a switch for controlling output and output release of the power boosted by the transformer to the commercial power system. The power converter includes a plurality of power converters. The power converter of each of the high speed communication unit is connected via a data line to transmit the respective output data of the plurality of power converters, the voltage output from each transformer based on the output data is connected in parallel through the output line As a power supply device using a solar cell module is characterized in that it is output to a commercial power system, it is possible to manufacture a device having a simple circuit configuration which is inexpensive because it determines the starting of the inverter device based on the open voltage. It also flexibly responds to deterioration of solar cell modules over time, changes in installation environment, and outside air temperature. There are possible effects.

Description

Power supply device using solar cell module {Power Supply Appartus Using Solar Cell Module}

The present invention relates to a power supply device using a solar cell module, and more particularly, when the inverter device can be started even when the weather conditions are different, the inverter device is quickly started, and unnecessary starting and stopping of the inverter device are required. It is possible to smooth the power supply by increasing the total power by using a plurality of power converters connected in parallel even in a load that cannot be supplied due to power shortage by connecting a plurality of power converters in parallel. It relates to a power supply using a solar cell module.

As the depletion of fossil fuels intensifies, a solar power generation system has been developed that converts DC power generated by solar cells into AC power by inverter devices and supplies power in connection with commercial power systems. In the process.

Power generation using solar cells is affected by weather conditions such as solar intensity and temperature. Therefore, the inverter device is set to stop automatically at the time when the solar cell does not generate power, such as at night, and to start automatically at the time when the solar cell of the day can generate power. That is, when the solar intensity decreases and the power supplied from the solar cell is less than the no-load loss of the inverter device, the inverter device is stopped. When the solar intensity increases and the power supplied from the solar cell is sufficient to operate the inverter device, the inverter The device needs to be activated.

As described above, a method for starting an inverter device by guessing the electric power supplied from the solar cell from the open voltage and the short circuit current of the solar cell has been developed. Here, the open-circuit voltage is an output voltage when the output terminal of the solar cell module is opened, and the reference voltage described in the following description means a voltage serving as a criterion for starting the inverter device. That is, when the open voltage of the solar cell module exceeds the reference voltage, it is determined that the solar cell module can supply sufficient power to the inverter device, and the inverter starting device starts the inverter device. As an example, there is a method of setting a predetermined voltage as a reference voltage and starting the inverter device when the open voltage is higher than the reference voltage. However, in this case, the reference voltage is a constant value regardless of whether the open voltage greatly changes due to deterioration of the solar cell module over time and changes in the outside air temperature. Therefore, even if the power supply of the solar cell module is sufficient, the inverter device does not start because the open voltage does not reach the reference voltage, or the inverter device starts because the open voltage reaches the reference voltage when the supply power of the solar cell module is insufficient. There is a problem of repeating hunting that stops. As described above, the hunting is repeated, which adversely affects the lifespan of components such as relays in the inverter device, thereby reducing the lifespan of the power supply device using the inverter device and the solar cell module.

In order to overcome this problem, Japanese Patent Laid-Open No. 08-126208 adds a value obtained by adding a criterion value to an open voltage at the time of the last system shutdown, and the state at which the state lasts a predetermined time. A method for starting an inverter device is described. According to this method, it is possible to set the open circuit voltage from the open circuit voltage at the stop even if the inverter device is stopped due to any problem during operation. Therefore, it is possible to set the reference voltage according to the deterioration of the solar cell over time and the outside air temperature, etc., and solve the problem that is unsuitable for setting the reference voltage at a constant value.

However, in the above technique, when the system is stopped by the sunset of the previous day, a value based on the open voltage at the sunset of the previous day is used as the reference voltage for starting the inverter device. At this time, since weather conditions such as the previous day and today's temperature are different, there is a problem in that the inverter device does not start because the open voltage of the solar cell is different even under the same solar intensity.

1 is a graph showing the relationship between the solar radiation intensity and the open voltage of the solar cell according to the difference in temperature. As an example, curve A shown in FIG. 4 shows the relationship between the solar intensity and the open voltage at a temperature lower than the curve B. FIG. As shown in FIG. 1, when the temperature is high even at the same solar intensity, the open voltage of the solar cell is lowered. If the curve A shown in Fig. 4 represents the open circuit voltage with respect to the temperature at the time of the system stop by the sunset of the previous day, and the solar radiation intensity at the system stop is X, then the open circuit voltage at that time becomes V. When the curve B indicates the open circuit voltage for the temperature when the inverter device is to be activated on the next day, the solar radiation intensity at which the open circuit voltage is V + α is Y. That is, the inverter device does not start even when the solar radiation intensity reaches X. The inverter device starts only when Y, which is a solar intensity higher than X, is reached. Even when sufficient DC power is supplied from the solar cell during this time, since the inverter device is not started, conversion to AC power is not possible, and thus, a considerable amount of power generation is lost. Α represents a criterion value.

Accordingly, the present invention has been made to solve the above problems, and the inverter device is quickly started when the inverter device can be started even when the weather conditions are different, so that unnecessary start and stop of the inverter device can be repeated. Solar cells that can smoothly supply power by increasing the total power by using a plurality of power converters connected in parallel even in a load that cannot be supplied due to power shortage by connecting a plurality of power converters in parallel. The purpose is to provide a power supply using a module.

An object of the present invention as described above is a solar cell module for generating direct current power by converting solar energy into electrical energy; A voltage detection device for measuring an open voltage, which is an output voltage of the solar cell module; An inverter device for converting DC power into AC power; A controller including a CPU for performing a control operation of the inverter device, a high speed communication unit, and a reference voltage source for providing an initial reference voltage; A transformer for boosting the voltage of AC power; A grid voltage current detection device for detecting grid voltage signals of a commercial power system; And an associated connection device provided between the transformer and the commercial power system to serve as a switch for controlling output and output release of the power boosted by the transformer to the commercial power system. The power converter includes a plurality of power converters. The power converter of each of the high speed communication unit is connected via a data line to transmit the respective output data of the plurality of power converters, the voltage output from each transformer based on the output data is connected in parallel through the output line It can be achieved by a power supply using a solar cell module characterized in that the output to the commercial power system.

At this time, the CPU, the inverter control device for outputting a PWM signal for the on, off operation control of the switching element of the inverter device; An inverter starting device for outputting a start signal for controlling the PWM signal output of the inverter control device to the inverter control device; And a linkage control device for comparing the output voltage signal of the transformer with the grid voltage signal of the commercial power system inputted from the grid voltage current detection device and outputting a linkage connection or disconnection signal to the linkage connection device and the inverter starting device. .

In addition, the inverter starting device, the linkage determination unit for determining whether the linkage with the commercial power system; A timer unit for displaying the time from the start signal input of the inverter device to the link completion signal input time of the link determination unit; Reference voltage setting means for setting an initial reference voltage as a reference voltage when an association completion signal of the association determination unit is input; A comparison unit for comparing the open voltage of the solar cell module input from the voltage detector with a reference voltage input from the reference voltage setting means when the associated time elapsed signal is input from the timer unit and outputting a start signal when the open voltage is large; A recording unit which records an input open voltage when an open voltage is input from the voltage detection device and a start signal is input from the comparison unit; And a counter unit for measuring the number of linkage failures of the linkage determination unit and outputting a reference voltage change signal to the reference voltage setting means when the measured number of times is measured up to a preset number.

The reference voltage setting means sets the reference voltage by adding a predetermined value larger than zero to the open voltage recorded in the recording means.

In addition, the predetermined value is 1V to 20V.

According to the present invention, since the start of the inverter device is determined based on the open voltage, a device having a simple and inexpensive circuit configuration can be manufactured. It has the effect of being flexible.

In addition, since the open voltage is automatically set according to the optimum criteria for use of the solar cell module, even if the weather conditions are different, the inverter device starts immediately if the starting condition is satisfied without delay. There is an effect that stable system operation can be realized by preventing repetition of stops in advance. In addition, since unnecessary starting and stopping of repetition is prevented, the burden on the power supply device using the inverter device and the solar cell module is reduced, thereby extending the life of the product.

In addition, in the power supply apparatus using the solar cell module according to the present invention, since a plurality of power converters can be connected in parallel by output lines to obtain power output at the same time, the scale of the power generation equipment can be expanded, and parallel connection can be achieved. Installation has a simple effect.

In addition, as a plurality of power converters are provided in parallel as described above, even if one power converter is down during startup, other power converters replace the power through mutual communication between high-speed communication units connected by data lines. There is a continuous and continuous effect on supply, and once the power converter is restored, it can also be started.

The following drawings, which are attached in this specification, illustrate preferred embodiments of the present invention, and together with the detailed description thereof, serve to further understand the technical spirit of the present invention. It should not be interpreted.
1 is a graph showing the relationship between the solar radiation intensity and the open circuit voltage of the solar cell according to the difference in temperature;
2 is a block diagram showing a circuit configuration of a power supply apparatus using a solar cell module according to the present invention;
3 is a block diagram showing a circuit configuration of one power converter according to the present invention;
4 is a block diagram showing the configuration of an inverter starting device according to the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

<Configuration of Power Supply Unit>

2 is a block diagram showing a circuit configuration of a power supply apparatus using a solar cell module according to the present invention. As shown in FIG. 2, the power supply device 10 using the solar cell module according to the present invention includes a plurality of power converters 10 ′. Since the plurality of power converters 10 'are all configured in the same configuration, the following description will focus on one power converter 10'.

3 is a block diagram showing a circuit configuration of one power converter according to the present invention. As shown in FIG. 3, the power converter 10 ′ according to the present invention includes a solar cell module 100, a voltage detector 200, an inverter device 300, a controller 400, and a transformer device 500. ), The grid voltage current detection device 600 and the associated connection device 700. In this case, the solar cell module 100, the inverter device 300, the transformer device 500, and the associated connection device 700 are connected in series with the commercial power system 800.

Here, the solar cell module 100 is a device for generating direct current power by converting solar energy into electrical energy. Such a solar cell module 100 is used in the art as a detailed description thereof will be omitted.

The voltage detecting device 200 according to the present invention is a device for measuring an open voltage, which is an output voltage of the solar cell module 100. The voltage detection device 200 is connected between the inverter device 300 connected in series with the solar cell module 100 to measure the open voltage of the solar cell module 100. While the inverter device 300 is operating, the output voltage of the solar cell connected to the inverter device 300 is measured, and the measured voltage is input to the inverter airway device and the associated control device.

The inverter device 300 according to the present invention is a device for converting DC power input from the solar cell into AC power. In this case, the inverter device 300 outputs AC power in which switching noise is removed by the filter circuit. The inverter device 300 uses a PWM control type inverter device 300 for turning on / off a switching element based on a pulse width modulation (PWM) signal input from an inverter control device 410 to be described later. good.

The control unit 400 according to the present invention includes a CPU 400-1, a high speed communication unit 400-2, and a reference voltage source 400-3.

The CPU 400-1 according to the present invention is a device for performing a control operation of the inverter device 300, and includes an inverter control device 410, an inverter starting device 420, and an associated control device 430.

Here, the inverter controller 410 is a device which is provided to be connected to the inverter device 300, and outputs a PWM signal for controlling the on / off operation of the switching element provided in the inverter device 300. The inverter controller 410 synchronizes the target output voltage signal and the triangular wave signal of a predetermined frequency with the grid voltage signal of the commercial power system 800 inputted from the grid voltage current detection device 600, respectively. It is generated as a signal and a carrier signal. A pulse signal is generated on the basis of the difference between the command value signal and the carrier signal and output as a PWM signal. In addition, the PWM signal generation and stop of the inverter control device 410 is controlled according to the start signal of the inverter starting device 420 described later. In addition, the inverter controller 410 may use any method and apparatus as long as it can generate a PWM signal using other methods.

4 is a block diagram showing the configuration of an inverter starting device according to the present invention. Inverter starting device 420 according to the present invention is provided to be connected to the inverter control device 410, a device for outputting a start signal for controlling the PWM signal output of the inverter control device 410 to the inverter control device 410. . As shown in FIG. 4, the inverter starting device 420 includes an association determination unit 421, a timer unit 422, a reference voltage setting unit 423, a comparison unit 424, a recording unit 425, and a counter unit. It consists of 426.

Here, the linkage determination unit 421 is a device for determining whether the power converter 10 'according to the present invention is linked to the commercial power system 800. The linkage determination unit 421 turns on the flag when the linkage connection signal is input from the linkage control device, and turns off the flag when the linkage release signal is input from the linkage control device. At this time, when the flag is turned on, the connection completion signal is output to the timer unit 422 and the reference voltage setting means 423.

The timer unit 422 according to the present invention is a device for counting the time from the start signal input of the inverter device 300 to the linkage completion signal input time of the linkage determination unit 421. That is, the timer 422 starts the clock when the start signal is input from the comparator 424, and stops the clock when the link completion signal is input from the link determining unit. The timer unit 422 stops counting when a predetermined time is displayed and outputs an associated time elapsed signal to the comparator 424 and the counter 426. At this time, the predetermined time to be displayed is a time for displaying a preset completion timer limit. If the association of the inverter starting device 420 is not completed until all of the predetermined time input in advance to the timer unit 422 has elapsed, the timer unit 422 determines that the association has failed and controls the inverter device 300 and the inverter. A stop signal is output to the device 410 and the start up of the inverter device 300 is tested again.

The reference voltage setting means 423 according to the present invention is a device for setting the initial reference voltage as the reference voltage when the link completion signal of the link determining unit 421 is input. Here, the initial reference voltage is preset to several hundred V according to the characteristics of the solar cell module 100. In addition, when the reference voltage change signal is input from the counter 426, the reference voltage setting means 423 sets the reference voltage by adding a predetermined value greater than zero to the open voltage recorded in the recording unit 425. At this time, the predetermined value is 1V to 20V, and preferably 10V is added to set the reference voltage.

The comparison unit 424 according to the present invention, when the associated time elapsed signal is input from the timer, the open circuit voltage of the solar cell module 100 input from the voltage detecting device 200 and the reference voltage input from the reference voltage setting means 423. Compare with At this time, when the open voltage is greater than the reference voltage, the start signal is output to the inverter device 300, the inverter control device 410, the recording unit 425, and the timer unit 422.

The recording unit 425 according to the present invention is an apparatus for recording the open voltage when the open voltage of the solar cell module 100 is input from the voltage detecting device 200 and the start signal is input from the comparator 424.

The counter unit 426 according to the present invention is a device for measuring the number of link failures of the link determination unit 421. The counter unit 426 increments the counter by one when the associated time elapsed signal is input from the timer unit 422. The counter unit 426 outputs a reference voltage change signal to the reference voltage setting unit when the counter reaches a predetermined number of times, and initializes the counter to zero. At this time, the predetermined number of times is set in advance, and in this embodiment, 2 to 5 times, preferably 3 times are set. The inverter starting device 420 tests the starting three times input to the inverter device 300 again to change the reference voltage when the number of failures of the linkage becomes a predetermined number input in advance. The predetermined number of times is not limited to three times, and the setting can be freely changed. As an example, it may be set to a configuration in which a value obtained by adding a predetermined value to the open voltage recorded in the recording unit 425 is set as the reference voltage every time a linkage fails. However, if the predetermined number is set too small, the reference voltage is immediately changed, and there is a problem that it is impossible to start the inverter device 300 when the open voltage of the solar cell module 100 rises slowly. On the contrary, if the predetermined number of times is set too many times, the reference voltage is not changed and the inverter device 300 is started regardless of the insufficient power supply of the solar cell module 100 to repeat hunting. There is a problem that increases the likelihood.

The linkage control device 430 according to the present invention is provided to be connected to the linkage connection device 700 and the inverter starting device 420, and is input from the output voltage signal of the transformer device 500 and the grid voltage current detection device 600. When the grid voltage signal of the commercial power system 800 is matched, the linkage connection signal is output to the linkage connection device and the inverter starting device 420. In addition, if the output voltage signal of the transformer 500 and the grid voltage signal of the commercial power system 800 input from the grid voltage current detection device 600 does not match, disconnection to the linkage connecting device and the inverter starting device 420. Output the signal. At this time, the output voltage signal of the transformer 500 is a control parameter set for generating the open circuit voltage of the solar cell module 100 input from the voltage detector 200 and the PWM signal output from the inverter controller 410. And a boost ratio set in the transformer 500. In addition, the voltage detection device may be connected between the boosting device and the coupling connection device 700 to directly detect the output voltage signal of the transformer device 500 and compare the voltage signal with the system voltage signal.

The high speed communication unit 400-2 according to the present invention is connected to the CPU 400-1 and connected to the high speed communication unit 400-2 provided in each power converter 10 ′ through a data line D. It is a device for mutually transmitting the output data of each power converter (10 ').

The reference voltage source 400-3 according to the present invention is a device for inputting a reference voltage to the reference voltage setting unit.

The transformer 500 according to the present invention is a device connected in series with the inverter device 300 to boost the voltage of AC power converted by the inverter device 300 at a predetermined boost ratio. At this time, the boost ratio is a boost ratio for boosting the voltage value of the AC power output by the inverter device 300 to the same level as the voltage maximum value of the system voltage of the commercial power system 800 when the fixed DC voltage minimum power is input. This boost ratio is previously input to the transformer 500.

The grid voltage current detection device 600 according to the present invention is a device for detecting the grid voltage signal of the commercial power system 800 and inputting it to the inverter controller 410 and the associated controller 430.

Linkage connection device 700 according to the present invention is provided to be connected in series between the transformer 500 and the commercial power system 800, and outputs the power boosted by the transformer 500 to the commercial power system 800 It is a device that acts as a switch to control the output. In more detail, when the continuous signal is input from the associated control device, the AC power output from the transformer 500 is connected to the commercial power system 800 by connecting the output terminal of the transformer 500 to the commercial power system 800. Supplied to. At this time, each power converter 10 'receives the respective output data through the high speed communication unit 400-2, and if the power supply from one power converter 10' is insufficient, each power conversion Power output from the device 10 ′ may be output in parallel to the commercial power system 800 by parallel connection through the output line P. FIG. On the other hand, when the link release signal is input from the link control device disconnects the output terminal of the transformer 500 and the commercial power system 800 to cut off the AC power supplied to the commercial power system 800.

As described above, those skilled in the art will understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. It is therefore to be understood that the above-described embodiments are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

10: power supply device
10 ': power converter
100: solar cell module
200: voltage detection device
300: inverter device
400:
400-1: CPU
410: inverter control device
420: inverter starting device
421: association determination unit
422: timer unit
423: reference voltage setting means
424: comparison unit
425: register
426: counter
430: linkage control device
400-2: High speed communication unit
400-3: reference voltage source
500: transformer
600: grid voltage current detection device
700: linkage device
800: commercial power system
D: data line
P: output line

Claims (5)

Solar cell module 100 for generating direct current power by converting solar energy into electrical energy;
A voltage detection device (200) for measuring an open voltage which is an output voltage of the solar cell module (100);
An inverter device 300 for converting the DC power into AC power;
A controller 400 including a CPU 400-1 performing a control operation of the inverter device 300, a high speed communication unit 400-2, and a reference voltage source 400-3 providing an initial reference voltage;
A transformer 500 for boosting the voltage of the AC power;
A system voltage current detection device 600 for detecting a system voltage signal of the commercial power system 800; And
Linked connection provided between the transformer device 500 and the commercial power system 800 serves as a switch for controlling the output and output release of the power boosted by the transformer device 500 to the commercial power system 800 Apparatus 700; comprising a plurality of power converter 10 ',
Each of the plurality of power converters 10 'is connected to each of the high speed communication units 400-2 through a data line D to transmit respective output data of the plurality of power converters 10', Based on the output data, the voltages output from the transformers 500 are connected in parallel through the output line P and output to the commercial power system 800.
The CPU 400-1,
An inverter controller 410 for outputting a PWM signal for controlling an on / off operation of the switching element of the inverter device 300;
An inverter starting device (420) for outputting a start signal for controlling the PWM signal output of the inverter control device (410) to the inverter control device (410); And
By comparing the output voltage signal of the transformer device 500 and the system voltage signal of the commercial power system 800 input from the system voltage current detection device 600, the linkage connection device 700 and the inverter starting device 420 Includes; linkage control device for outputting a linkage connection or disconnection signal 430;
The inverter starting device 420,
Linkage determination unit 421 for determining whether or not the linkage with the commercial power system (800);
A timer unit 422 for displaying a time from the start signal input of the inverter device 300 to the link completion signal input time of the link determination unit 421;
Reference voltage setting means (423) for setting an initial reference voltage as a reference voltage when the link completion signal of the link determining unit (421) is input;
When the associated time elapsed signal is input from the timer 422, the open voltage of the solar cell module 100 input from the voltage detector 200 is compared with the reference voltage input from the reference voltage setting means 423. A comparator 424 for outputting a start signal when the open voltage is large;
A recording unit 425 for inputting an open voltage from the voltage detection device 200 and recording the input open voltage when the start signal is input from the comparison unit 424; And
A counter unit 426 which measures the number of linkage failures of the linkage determination unit 421 and outputs a reference voltage change signal to the reference voltage setting means 423 when the measured number of times is measured up to a preset number of times. Power supply device using a solar cell module, characterized in that. delete delete The method of claim 1,
The reference voltage setting means (423) is a power supply device using a solar cell module, characterized in that to set the reference voltage by adding a predetermined value greater than zero to the open voltage recorded in the recording unit (425). The method of claim 4, wherein
The predetermined value is a power supply device using a solar cell module, characterized in that 1V to 20V.

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