JP2000003224A - Grid-connected photovoltaic power generator - Google Patents

Abstract

(57) [Summary] [PROBLEMS] In a grid-connected photovoltaic power generation system, by incorporating a self-output performance evaluation function into the system itself, it is possible to use an ordinary person without using a dedicated measuring instrument and without relying on experts. The present invention enables even a user of a certain solar power generation device to easily evaluate the output performance of a solar cell array or an inverter circuit. SOLUTION: A DC output from a solar cell array 2 is converted to an AC output by an inverter circuit 21 in a connection inverter 3, and a connection operation to a system power supply 6 is performed. The control circuit 22 controls the inverter circuit 21 based on the output current Ia and the output voltage Va from the solar cell array 2 so that the solar cell array 2 operates at the maximum generated power Pmax. In the control circuit 22, the received solar radiation intensity Eo at the time of rating is
The output performance of the solar cell array 2 is evaluated based on the cell operating temperature Tc, the short-circuit current Isc, the maximum value Pa _[max] , the maximum voltage value Va _[max] , and the maximum current value Ia _{[max] of the} measured output power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grid-connected photovoltaic power generator which converts a solar cell output into AC power and operates by connecting to a commercial power distribution line of a power company.

[0002]

2. Description of the Related Art A grid-connected photovoltaic power generator converts the output of a solar cell array into AC power by an inverter circuit, performs a grid connection operation with a commercial power distribution line, and generates an inverter output that exceeds the power consumption of a load. The power can be sold to a power company by flowing backward into the commercial distribution line. The output characteristics of the solar cell array are determined by the solar radiation intensity of the array and the temperature of the solar cell element,
The output of a photovoltaic generator constantly fluctuates. Therefore,
In the evaluation of the output performance of a photovoltaic power generation system, measurement of the solar radiation intensity of the solar cell light receiving surface at the installation site of the solar cell with a pyranometer, measurement of the solar cell operating temperature with a thermometer, output current, output voltage and output of the solar cell It is necessary to measure the power and the output power of the inverter circuit simultaneously, and to measure the output characteristics (output voltage-output current characteristics) of the solar cell array, a dedicated IV curve tracer is required. Therefore, it is difficult to evaluate whether the outputs of the solar cell array and the inverter circuit are normal.

[0003]

In order to effectively use a solar power generation device, it is essential that the solar cell array and the inverter circuit, which are components of the solar power generation device, are normal. It is important to evaluate whether the output is normal and whether the inverter circuit is normal. In particular, the solar cell array is usually installed on the roof of a house, and destroys the solar cell due to a typhoon, a tile blown off during a strong wind, or a flying object (for example, a large leaf).
It is difficult to visually inspect the solar cell for light reception failure, dirt on the surface of the solar cell, and other defects of the solar cell. Inspections on the roof generally rely on specialists. Furthermore, as described above, a special measuring instrument (IV curve tracer) is required for the output characteristic measurement, and it is left to an expert.

The present invention was conceived in order to solve the above-mentioned problems. By incorporating a self-output performance evaluation function into the device itself, it is possible to use a dedicated measuring instrument without relying on an expert and without relying on an expert. It is an object of the present invention to provide a grid-connected photovoltaic power generator that allows even a user of the photovoltaic power generator as an ordinary person to easily evaluate the output performance of a solar cell array and an inverter circuit.

[0005]

SUMMARY OF THE INVENTION A grid-connected photovoltaic power generator according to the present invention comprises a solar cell array, an inverter circuit for converting a DC output of the solar cell array into an AC output, and an output current of the solar cell array. And a control circuit for controlling the output of the solar cell array to be the maximum generated power based on the output voltage and the output voltage. And so that the evaluation of the output performance of the solar cell array does not require the use of a dedicated measuring instrument, and does not need to rely on an expert, at least the output current and the output voltage are provided to the control circuit itself. And an output characteristic inspection function utilizing the function.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a grid-connected solar power generation system according to the present invention will be described below in detail with reference to the drawings.

[First Embodiment] FIG. 1 is a block diagram showing a schematic configuration of a grid-connected photovoltaic power generator according to a first embodiment. The system interconnection type solar power generation device 1 is roughly composed of a solar cell array 2 and an interconnection inverter 3. Reference numeral 4 is a distribution board in a house, 5
Denotes various loads in a house, and 6 denotes a system power supply of a power company. The DC power generated by the solar cell array 2 is converted by the interconnection inverter 3 into AC power of the same quality as the system power supply 6, and AC power is supplied to the load 5 via the distribution board 4 by interconnection operation, The surplus power flows backward to the system power supply 6 via the distribution board 5. A collection of the minimum unit of solar cells is called a solar cell module. The solar cell modules 11 are connected in series to form a solar cell string 12, and a backflow prevention diode 13 is connected to each solar cell string 12. The solar cell array 2 is configured by connecting a plurality of series-connected bodies of the solar cell strings 12 and the backflow prevention diodes 13 in parallel. The backflow prevention diode 13 is for preventing a backflow of current from a higher voltage to a lower voltage due to a variation in output voltage between the solar cell strings 12.

The interconnection inverter 3 includes an inverter circuit 21 including a plurality of switching elements for performing PWM (pulse width modulation) and a filter for shaping a waveform, a control circuit 22 for controlling the inverter circuit 21, A direct current detector (shunt) 23 connected in series between the solar cell array 2 and the inverter circuit 21 to detect the output current Ia of the solar cell array 2, and connected in series to the output side of the inverter circuit 21 And an AC current detector (shunt) 24 for detecting the output current Ib of the inverter circuit 21, a switch 25, a display unit 26, a manual switch 27 and the like.

FIG. 2 is a block diagram showing a more specific configuration of the control circuit 22. The control circuit 22 converts the output current from the solar cell array 2 into a resistor divider to detect the output voltage Va of the solar cell array 2 and converts the output current from the inverter circuit 21 into a resistor divider. The voltage divider 32 detects the output voltage Vb of the inverter circuit 21 by conversion, and the A / D converter 3 converts each of the four analog signals into a digital signal.
3, an MPU (microprocessor unit; central processing unit) 34 for executing arithmetic processing, and data input means 35. The MPU 34 has, as its function, a voltage measuring means for measuring four voltage signals (output voltage Va of the solar cell array 2, output current Ia, output voltage Vb of the inverter circuit 21, and output current Ib) by the A / D converter 33. 41, data calculation processing means 42 for executing various calculations based on the measured data, and data of specification values of the solar cell array 2 and the inverter circuit 21 required for output evaluation input from the data input means 35 are stored. A data storage means 43 for storing data of a calculation result by the data calculation processing means 42, and an inverter circuit 21 based on a calculation result by the data calculation processing means 42.
, An abnormality control unit 44 for specifying an abnormality based on the result of the operation performed by the data operation processing unit 42 based on the four voltage signals, and a signal indicating whether there is an abnormality from the abnormality specification unit 45. Input and display part 26
And a display control means 46 for controlling the display to be performed.

The output characteristics of a solar cell vary depending on the amount of solar radiation and cell temperature. That is, as the amount of solar radiation increases, the maximum generated power also increases, and as the cell temperature increases, the maximum generated power decreases. The inverter circuit 21 in the interconnection inverter 3 uses the solar cell array 2 which is affected by the fluctuations in the amount of solar radiation and the cell temperature as a power source, and the inverter control means 44 in the control circuit 22 calculates the calculation result by the data calculation processing means 42. A solar cell maximum output point tracking method is adopted so as to extract the maximum generated power at each of the current values of the solar radiation amount and the cell temperature which fluctuate based on the above. This method is a control method for controlling the input impedance of the inverter circuit 21 so that the operating point of the solar cell array 2 directly connected to the inverter circuit 21 is adjusted to the maximum generated power. FIG. 3 shows a load characteristic straight line indicating the maximum power generation point Pmax at which the output of the solar cell array becomes maximum on the output voltage-output current characteristic curve of the solar cell array determined by the amount of solar radiation and the cell temperature. Thus, the input impedance of the inverter circuit 21 is controlled. This will be specifically described with reference to FIG. When the interconnection inverter 3 is started, the output voltage Va of the solar cell array 2 is
Is close to the open circuit voltage Voc, and the output current Ia hardly flows, so that the input impedance is large. Therefore, the input impedance is gradually reduced (the output voltage Va is reduced and the output current Ia is increased), and the output voltage −
The operating point on the output current characteristic is raised from the open voltage side to the maximum generated power point Pmax, and the maximum generated power point Pmax is tracked. The variable circuit of the input impedance is provided in the inverter circuit 21 and is controlled by the inverter control means 44.

Using the input impedance control of the inverter circuit 21 by the inverter control means 44, the output performance of the solar cell array 2 is evaluated. That is, as an operation sequence that is automatically performed at a preset measurement interval (for example, once a month) when the output of the inverter circuit 21 is equal to or more than a fixed value, after temporarily stopping the interconnection operation, an arrow in FIG. As shown by a, the input impedance of the inverter circuit 21 is gradually reduced from infinity, and the operating voltage of the solar cell array 2 is changed within the input voltage range b of the inverter circuit 21. The output voltage Va (= Va × Ia) of the solar cell array 2 is calculated by the voltage measurement means 41 in the control circuit 22 and the output power Pa (= Va × Ia) of the solar cell array 2 is measured by the data calculation processing means 42. The maximum voltage value Va _[max] , the maximum output power value Pa _[max] , and the maximum current value Ia _[max] in the input voltage range b of FIG. Confuse. On the other hand, the electrical characteristics data of the solar cell array 2 at the rated time, that is, the solar radiation intensity 1.0 kW / m ² , the cell temperature 25
Open circuit voltage Voc, short-circuit current Isc, rated maximum output Pma
x is set in the data storage unit 43. The data operation processing means 42 outputs the three values Va _[max] , Pa _[max] and Ia _[max] obtained by the input impedance control _.
And three values Voc and I read from the data storage means 43.
Based on sc and Pmax, output performance evaluation for the rated specification of the solar cell array 2 is performed as follows.

(1) Calculate the solar radiation intensity Eo and the solar cell operating temperature Tc (° C.) when Pa _[max] is measured.

Eo = Ia _[max] / Isc ………………………………………………………………………………………………………………….
/ ° C), from Va _[max] = Voc− (25−Tc) · Kv · Voc, Tc = 25− (Voc−Va _[max] ) / (Kv · Voc) (2) The received solar radiation intensity of the rated maximum output Pmax of the solar cell array 2 is Eo, the operating temperature of the solar cell is Tc (° C.), and the maximum output power temperature coefficient of the solar cell array 2 is Kp (W /
° C), Pmax '= Eo · Pmax · {1- (25−Tc) · Kp}
……………., The received solar radiation intensity Eo and the operating temperature T
The theoretical maximum generated power Pmax 'at the time of c can be calculated without using a pyranometer or a thermometer.

(3) Calculate the ratio Rn between Pa _[max] and Pmax '.

Rn = Pa _[max] / Pmax ′ ………………………………………………………………………………………………………………………………………………………………………………………………………………… …………………………… ………………………… 表示 表示 表示 表示 表示 表示 表示 表示. Thus, the performance of the solar cell array 2 with respect to the rated specifications can be confirmed.
Further, it is also possible to determine whether the abnormality is normal or abnormal in the abnormality specifying means 45, display the result on the display unit 26, and confirm the performance of the solar cell array 2 with respect to the rated specification. For example, if 0.9 <Rn ≦ 1, the output of the solar cell array is normal. For example, if 0.7 <Rn ≦ 0.9, no inspection is required. For example, if Rn ≦ 0.7, the output of the solar cell array is normal. Are displayed as abnormal.

The above-mentioned ratio Rn is measured at the above-mentioned intervals and stored as history data, so that the solar cell array 2 after the installation of the photovoltaic power generator 1 can be obtained.
Can be clarified over time with respect to the rated output.

In the data processing means 42,
When the ratio dI / dV of the current change to the voltage change in the case where the voltage is changed from the open voltage of the solar cell array to the minimum input voltage of the inverter circuit 21 through the optimal operating point, it is assumed to be normal when the ratio changes from large to small. When the transition from large to small to large to small (this corresponds to the occurrence of a dent in the characteristic of the output voltage-output current characteristic curve), it is regarded as abnormal (light receiving failure of solar cell array, output abnormal), and You may make it display on the display part 26.

Further, as shown by the arrow a in FIG. 5, the input impedance of the inverter circuit 21 is gradually reduced from infinity to the input voltage range b of the inverter circuit 21.
When measuring the output voltage Va and the output current Ia of the photovoltaic array 2 by changing the operating voltage of the photovoltaic array 2 inside, a plurality of sets of Va and Ia are acquired with a fixed voltage change width, and The corresponding data may be stored in the data storage unit 43, and the numerical data may be displayed as a table on the display unit 26 by a predetermined operation. Alternatively, if the respective values are plotted and displayed as the output voltage in the X-axis direction and the output current in the Y-axis direction, the output voltage-output current characteristic curve of the solar cell array 2 can be easily obtained.

The time required for the above series of measurements is as short as several minutes. After a series of measurements is completed, the photovoltaic power generator 1 returns to the interconnection operation.

In the above, the measurement is automatically repeated at a predetermined measurement interval. However, the above-described measurement operation is performed when the user or the inspector operates the manual switch 27 as necessary. You may.

The output performance of the inverter circuit 21 is evaluated based on the input / output power ratio (power conversion efficiency) of the inverter circuit 21. When the power conversion efficiency is 1/3 or more of the rating, the power conversion efficiency η of the inverter circuit 21 is calculated as follows: η = (Ib · Vb) / (Ia · Va)... Calculated by Therefore, the power conversion efficiency can be calculated without using a power meter and without consuming running costs. The data storage means 43 is based on the initial power conversion efficiency η ₀ when the photovoltaic power generator 1 is installed.
The output performance of the inverter circuit 21 can be evaluated by comparing the power conversion efficiency η according to the equation for each measurement with η ₀ and displaying the transition.

Embodiment 2 Embodiment 2 relates to the interconnection inverter 3 shown in FIG. 1 and a remote controller 7 corresponding thereto. FIG. 6 is a front view of the remote controller 7. In FIG. 6, reference numeral 51 denotes a display unit composed of 7-segment LEDs; 52, a W display LED which is lit when displaying the instantaneous value of the generated power (watt); 53, which is lit when displaying the integrated power amount within a certain period. The integrated power amount display LED 54 is turned on when displaying the integrated power amount from the installation of the apparatus to the present, and the total power amount display LED 55 is turned on when displaying the carbon dioxide emission reduction amount. ₂ Emission reduction LED, 56 is a second LED that lights up when displaying the elapsed time since power recovery in the case of power failure in seconds, 57 is an LED that indicates the interconnected operation state,
Reference numeral 58 denotes an LED indicating an operation stop state; 59, an LED indicating an independent operation state when the load 5 is operated only by electric power from the interconnection inverter 3 without receiving power supply from the system power supply 6; A start / stop button for instructing start / stop of the system inverter 3, an environmental contribution monitor button 62 for displaying a carbon dioxide emission reduction amount, and a switch 63 for switching between a period integrated power amount display and a total integrated power amount display. A display switching button 64 is an integrated power amount reset button for reset-clearing the stored integrated power amount during the period. Literature "Study on CO ₂ emissions per unit of solar power generation system" (Publisher: Chemical Industry Association) and "global warming impact analysis of power plant": According to the (publication Central Research Institute of Electric Power Industry 1991), carbon dioxide (CO ₂ ) Is 0.196 kg-C / kWh per kWh for oil-fired power generation in terms of carbon (kg
-C represents mass in terms of carbon). On the other hand, in the case of crystalline solar cells, the value obtained by dividing the amount of CO ₂ emitted when manufacturing system devices such as solar cells by the amount of power generation for 20 years, assuming the service life of 20 years, is the amount of emissions from solar power generation. Amount. The value is 0.017 kg-C / kW in terms of carbon.
h. The value obtained by subtracting the photovoltaic power generation from the oil-fired power generation, that is, 0.196−0.017 = 0.179 k
gC / kWh is the amount of CO ₂ emission reduction (carbon equivalent) per 1 kWh. The DC power generated by the solar cell array 2 is converted into an inverter circuit 21 of the interconnection inverter 3.
The AC power is converted to AC power, and the grid-connected power source 6 is connected to the grid power source, and the power generated by the grid-connected solar power generation device 1 in this way is defined as AkWh. Pressing the environmental contribution monitor button 62, together with the CO ₂ emission reduction amount LED55 is lit, the 0.179 × Akg-C / kWh CO
₂ is displayed on the display unit 51 of the remote controller 7 composed of 7-segment LEDs as the emission reduction amount (carbon equivalent). When performing the molecular weight conversion of carbon dioxide, multiply the carbon conversion value by the molecular weight ratio of CO ₂ / C of 44/12,
0.656 × Akg-C / kWh may be displayed. The display unit 51 is not limited to a 7-segment LED, but may be a liquid crystal display, a plasma display, a fluorescent tube display, or the like. Further, the configuration may be such that the carbon dioxide emission reduction amount based on the carbon atom weight ratio and the carbon dioxide emission reduction amount based on the carbon dioxide molecular weight ratio are simultaneously displayed, or may be configured to be alternately displayed. Good. In the case of display switching, the display is switched each time the display switching button 63 is pressed. The above numerical values are provisionally determined, and the calculation method may be the same even if the numerical values are changed. The display as described above allows the user to recognize how much contribution has been made to the reduction of carbon dioxide emissions.

When the interconnection inverter 3 is normal, W
The display LED 52 is turned on. When the voltage of the system power supply 6 exceeds the set value specified in the interconnection operation consultation when the interconnection inverter 3 is in the interconnection operation and the output control function is activated, and the continuous operation of the photovoltaic power generator 1 When the output power is controlled to be suppressed by the temperature rise caused by the above, the W display LED 52 blinks. As a result, the normal state and the output suppression state can be distinguished and notified to the user or the inspector. In addition, by changing the blinking interval of the W display LED 52, the output control function is activated when the voltage of the system power supply 6 exceeds the set value specified in the interconnection operation consultation, and when the output control function is operated continuously. It may be configured to distinguish the case where the output power is controlled to be suppressed by the temperature rise. Further, a buzzer is provided, and when the interconnection inverter 3 is normal, the buzzer is disabled, and when the interconnection inverter 3 is in the interconnection operation, the voltage of the system power supply 6 In the case where the output control function operates beyond the set value specified in, and the case where the output power is suppressed and controlled by the temperature rise due to the continuous operation of the photovoltaic power generator 1,
A buzzer may be sounded. In this case, by changing the oscillation frequency of the buzzer, the output control function is activated when the voltage of the system power supply 6 exceeds the set value specified in the interconnection operation consultation, and the continuous operation of the photovoltaic power generator 1 It may be configured to distinguish the case where the output power is controlled to be suppressed by the temperature rise.

[0024]

According to the first aspect of the present invention, there is provided a grid-connected photovoltaic power generator having a control circuit for controlling the output of the photovoltaic array to the maximum generated power based on the output current and the output voltage of the photovoltaic array. According to the present invention, since the control circuit itself inspects the output characteristics of the solar cell array, it is easy to evaluate the output performance of the solar cell array without using a dedicated measuring instrument or relying on an expert. Can be done.

According to the second aspect of the present invention, the maximum generated power Pa _[max] can be obtained based on changing the operating point of the solar cell array by changing the input impedance of the inverter circuit.

According to the third aspect of the present invention, the operating temperature Tc of the solar cell array is determined from the difference between the rated open circuit voltage Voc of the solar cell array and the voltage Va _[max] when the input impedance of the inverter circuit is infinite. The calculated maximum value I of the output current of the solar cell array with respect to the short-circuit current Isc at the time of rating
Since the received solar radiation intensity Eo is calculated from the ratio of a _[max] , the operating temperature of the solar cell array and the received solar radiation intensity can be known without using a thermometer or a pyranometer. The theoretical maximum generated power P at the time of measurement from the rated maximum generated power Pmax of the solar cell array, the operating temperature Tc, and the received solar radiation intensity Eo.
max 'can be calculated.

According to the invention of claim 4, the output performance evaluation of the solar cell array is performed by comparing the maximum generated power Pa _[max] calculated in claim 2 with the maximum generated power Pmax 'calculated in claim 3. It can be easily obtained.

According to the fifth aspect of the present invention, the ratio dI / dV of the current change to the voltage change from the vicinity of the open circuit voltage of the solar cell array toward the optimum operating point is calculated.
It is possible to easily determine the presence or absence of a light receiving failure or output abnormality of the solar cell array.

According to the invention of claim 6, the product Ib · Vb of the AC current and the AC voltage of the inverter circuit output is divided by the product Ia · Va of the current and the voltage of the output of the solar cell array to obtain the power of the inverter circuit. Since the conversion efficiency is calculated, the power conversion efficiency can be obtained without using a wattmeter and without consuming running costs.

According to the seventh aspect of the present invention, the amount of carbon dioxide emission reduction is displayed regardless of the carbon atom weight ratio or the carbon dioxide molecular weight ratio. At a glance, you can see if you are contributing to the reduction of carbon emissions, and raise awareness of preventing global warming.

According to the invention according to claim 8, when the output control function is operated when the system power supply voltage exceeds a specified set value during the interconnection operation, it is possible to notify the user or the inspector of the output control function, Further, when the output power is controlled to be suppressed by the temperature rise caused by the continuous operation of the photovoltaic power generator, the fact can be notified to the user or the inspector.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a grid-connected solar power generation device according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a specific configuration of a control circuit of the inverter circuit in Embodiment 1.

FIG. 3 is a characteristic diagram showing output voltage-output current characteristics of the solar cell array according to the first embodiment.

FIG. 4 is an explanatory diagram showing an output operation point of the solar cell array according to the first embodiment.

FIG. 5 is an explanatory diagram of a maximum voltage value, a maximum output power value, and a maximum current value within an input voltage range of the inverter circuit obtained by impedance control of the inverter circuit according to the first embodiment;

FIG. 6 is a front view showing the appearance of a remote controller for the interconnected inverter according to the second embodiment;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Grid connection type photovoltaic power generator, 2 ... Solar cell array, 3 ... Interconnection inverter, 4 ... Distribution board, 5
... Load, 6 ... System power supply, 7 ... Remote controller, 11 ... Solar cell module, 12 ... Solar cell strings, 13 ... Backflow prevention diode,
21 ... Inverter circuit 22 ... Control circuit 2
3 ... DC current detector, 24 ... AC current detector,
26 ...... Display unit, 51 ...... Display unit, 52 ...... W display LED, 55 ...... CO ₂ emission reduction LED, 62 ...
… Environmental contribution monitor button

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Keiji Morimoto 22-22, Nagaikecho, Abeno-ku, Osaka City, Osaka Inside Sharp Corporation (72) Inventor Tsukasa Takebayashi 22-22, Nagaikecho, Abeno-ku, Osaka City, Osaka F term (reference) 5G066 HA13 HA30 HB06 5H007 AA12 AA17 BB07 CC03 CC09 DA04 DB02 DB12 DC02 DC05 FA13 FA19 5H420 BB02 BB03 BB14 CC03 DD03 DD08 EA45 EB26 EB39 FF03 FF04 FF05 FF22 KK10 LL01 LL10 LL10 LL10

Claims (8)

[Claims] 1. A control for controlling an inverter circuit for converting a DC output of a solar cell array into an AC output so that an output of the solar cell array becomes a maximum generated power based on an output current and an output voltage of the solar cell array. A system interconnection type photovoltaic power generator having a circuit, wherein the control circuit has a function of inspecting an output characteristic of the solar cell array. 2. The function of inspecting the output characteristics of the solar cell array provided in the control circuit is to reduce the operating point of the solar cell array within the input voltage range of the inverter circuit by gradually reducing the input impedance of the inverter circuit from infinity. The grid-connected solar power generation apparatus according to claim 1, further comprising means for changing the maximum power generation point based on the output current and output voltage of the solar cell array at each operating point. 3. A control circuit of the inverter circuit includes means for storing electrical characteristic data at a rated time of the solar cell array, and operation of the solar cell array based on a difference between an open-circuit voltage at a rated time and a voltage at an infinite input impedance. Means for calculating the temperature;
Means for calculating the received solar radiation intensity from the ratio of the output current of the solar cell array at the lower limit of the input voltage range of the inverter circuit to the short-circuit current at the rated time, the rated maximum generated power of the solar cell array, the operating temperature, the received solar radiation intensity, 3. A grid-connected solar power generation apparatus according to claim 2, further comprising: means for calculating a maximum generated power point at the time of measurement from the system. 4. The control circuit of the inverter circuit compares the maximum generated power of claim 2 calculated based on the output current and output voltage of the solar cell array with the maximum generated power at the time of measurement based on the rating of claim 3. The grid-connected photovoltaic power generator according to claim 3, further comprising: 5. The control circuit of the inverter circuit according to claim 1, further comprising means for calculating a ratio of a current change to a voltage change in a direction from the vicinity of the open-circuit voltage of the solar cell array toward the optimum operating point. The grid-connected photovoltaic power generator according to any of the above. 6. A control circuit of the inverter circuit calculates a power conversion efficiency of the inverter circuit by dividing a product of the AC current and the AC voltage output from the inverter circuit by a product of the output current and the output voltage of the solar cell array. The grid-connected photovoltaic power generator according to any one of claims 1 to 5, further comprising: 7. Assuming that the same amount of power as that generated by the solar cell array was generated by oil-fired power generation,
The grid-connected solar power generation device according to claim 1, wherein the system is configured to calculate and display a reduced amount of carbon dioxide emission in the case of photovoltaic power generation as compared with oil-fired power generation. 8. When the output control function operates when the system power supply voltage exceeds a specified set value during the interconnection operation, or when the output power is suppressed by the temperature rise caused by the continuous operation of the photovoltaic power generator, the output power is suppressed and controlled. The grid-connected solar power generation apparatus according to claim 1 or 7, wherein the system is configured to notify the user of the fact when the system is in use.