JP3788061B2 - Power control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power control equipment having a function of controlling the power supply for melts snow or ice on the solar cell.
[0002]
[Prior art]
The solar power generation system has a solar cell and a power supply control device, and this power supply control device processes a normal power supply function for AC conversion of the power generation output of the solar cell and a system power supply to the solar cell. Some power conditioners have a control function for supplying a heat generation current to melt snow. This power conditioner generally includes at least a DC / DC converter, a smoothing capacitor, an inverter, a microcomputer built-in control device, and a system-side switch. In such a system, the power generation output of the solar cell is boosted by a DC / DC converter, smoothed by a smoothing capacitor, converted to AC power by an inverter, and supplied to a load under the control of a microcomputer in the control device. However, if this supplied power is surplus, the surplus power is reversely flowed to the system power supply connected to the system-side switch, and the solar cell is not generating or lacking power at night or in the rain. When the AC power supplied to the load is insufficient, the system power can be supplied by connecting the system power to the load. And when the sunlight is blocked by snow or ice on the solar battery, for example, to turn on the system side switch and power the system power to melt the snow or ice (this is called melting snow) This inverter is connected to a conditioner. In this power conditioner, the inverter circuit functions as a full-wave rectifier circuit, so that the output from the system power supply connected to the system-side switch is full-wave rectified. The output is smoothed by a smoothing capacitor, and the DC / DC converter functions as a step-down circuit to step down the smoothed output. There is something that melts snow.
[0003]
[Problems to be solved by the invention]
In such a conventional power supply control device, the time has elapsed since the start of snow accumulation in the solar cell, and therefore, it should be sunny and there is a solar cell power generation output. May be greatly reduced or completely eliminated. In such a case, when the power conditioner tries to start the snow melting operation, the internal capacitor is in an uncharged state, and a large charging current accompanying the start of the snow melting operation is passed through the system-side switch. As a result, the system side switch may be damaged, or the power conditioner itself may not operate because it is not charged because the capacitor is not charged. Also, since this occurs because the timing of the start of the snow melting operation is unknown, if the timing of the start is known early, before the power generation output of the solar cell greatly decreases, Since the snow melting operation can be started, it is possible to avoid the damage of the system side switch or the malfunction of the power conditioner. Furthermore, if the snow melting operation is not smooth, power is wasted.
[0004]
Therefore, in the present invention, it is a common problem to be solved mainly to enable the snow melting operation to be started smoothly without wasting power consumption wastefully.
[0005]
Other problems to be solved by the present invention will become apparent from the following description.
[0006]
[Means for Solving the Problems]
In the present invention, a normal control function that is connected between the solar cell and the system power source and converts the power generation output of the solar cell to AC, and the system power source is processed to supply a heating current to the solar cell to melt the snow. A power conditioner having a control function for charging and a charging current supply means for supplying a charging current to a capacitor in the power conditioner when the power conditioner starts snow melting control. The common problem mentioned above is solved.
[0007]
Here, the snow melting includes not only melting snow accumulated by snowfall on the solar cell but also melting ice formed by freezing the solar cell due to rain or the like.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a power supply control device according to an embodiment of the present invention will be described in detail with reference to the drawings by applying the power supply control device to a solar power generation system incorporating the power supply control device.
[0009]
(Embodiment 1)
In the power supply control device according to the first embodiment of the present invention, the normal control function for AC-converting the power generation output of the solar cell, and the control for processing the system power supply and supplying the heating current to the solar cell to melt snow A power conditioner having a function, and charging current supply means for supplying a charging current to a capacitor in the power conditioner when the power conditioner starts snow melting control. Is able to start the snow melting operation smoothly.
[0010]
Hereinafter, Embodiment 1 of the present invention will be described with reference to FIGS. 1 is a circuit block diagram of a photovoltaic power generation system in which a power supply control device is incorporated, FIG. 2 is a detailed circuit diagram of a power conditioner in the power supply control device of FIG. 1, and FIG. 3 is the power supply control device. It is a detailed circuit diagram of the AC / DC converter in the inside.
[0011]
Referring to FIG. 1, reference numeral 1 denotes a solar cell, and reference numeral 2 denotes a power supply control apparatus according to the first embodiment. The power supply control device 2 is connected between the solar cell 1 and the system power supply 3 and performs a normal operation control by a normal operation command input, and a snow conditioner operation control by a snow melting operation command input, An AC / DC converter 22 that converts AC to DC is used. The system power supply 3 includes a first system power supply 3 a for the power conditioner and a second system power supply 3 b for the AC / DC converter 22.
[0012]
Referring to FIG. 2, the power conditioner 21 includes a first filter 2a, a first smoothing capacitor C3, a DC / DC converter 2b, a second smoothing capacitor C4, an inverter 2c, a second filter 2d, a system side switch 2e, and A first control device 2f is provided. When there is a normal operation command input to the first control device 2f, the first control device 2f controls the normal operation. In this case, the first control device 2f turns off the transistor TR2 in the DC / DC converter 2b, the transistor TR1 is switched, the transistors TR3 to TR6 in the inverter 2c are switched, and the system side switch 2e is driven ON or OFF as necessary. Then, the power generation output of the solar cell 1 is smoothed by the first smoothing capacitor C3 via the first filter 2a, and then boosted by the switching operation of the transistor TR1 in the DC / DC converter 2b. The boosted power output of the solar cell 1 is smoothed by the second smoothing capacitor C4, input to the inverter 2c, and converted into alternating current by the inverter 2c. The power generation output of the solar cell 1 converted into alternating current is converted into a sine wave by the second filter 2d and supplied to a load (not shown) or via the system switch 2e to the first system power supply 3a side. Reverse tide. In this case, the 1st control apparatus 2f monitors the electric power generation output of the solar cell 1, and the output of the inverter 2c, and performs required control operation | movement.
[0013]
When there is a snow melting command input to the first control device 2f, the snow melting operation is controlled. In this case, the first controller 2f switches the transistor TR2 in the DC / DC converter 2b, turns off the transistor TR1, and turns off the transistors TR3 to TR6 in the inverter 2c (to form a diode bridge). Alternatively, switching driving (for boosting) is performed, and the system-side switch 2e is driven ON. Thus, the first system power supply 3a is input to the inverter 2c via the system switch 2e and the second filter 2d. When each of the transistors TR3 to TR6 in the inverter 2c is OFF, the output of the first system power supply 3a is full-wave rectified by the diodes D3 to D6 parallel to the transistors TR3 to TR6, or the transistors TR3 to TR6 are switched. After that, it is smoothed by the second smoothing capacitor. The smoothed power supply for melting snow is stepped down by the switching operation of the transistor TR2 in the DC / DC converter 2b. The step-down output of the first system power supply 3a is supplied to the solar cell 1 through the first smoothing capacitor C3 and the first filter 2a. The solar cell 1 generates heat by the output of the first system power supply 3a and melts snow as a heating element.
[0014]
Next, the AC / DC converter 22 uses the second system power supply 3b as an AC / DC as a charging current supply means for supplying a charging current to the capacitor C4 in the power conditioner 21 when the power conditioner 21 starts the snow melting control. DC conversion is performed, and the voltage is stepped up and down and input to the power conditioner 21.
[0015]
Referring to FIG. 3, this AC / DC converter 22 includes capacitors C6 and C7, a diode D7, a transistor TR7, a coil L6, a full-wave rectifier circuit 2g, a transformer TS, and a second control device 2h with a built-in microcomputer. ing. At the start of the snow melting operation, the second control device 2h performs full-wave rectification on the output of the second system power supply 3b via the transformer TS by the full-wave rectifier circuit 2g, smoothes it by the smoothing capacitor C7, and converts it into direct current. The TR7 is subjected to switching control and boosted, and then input to the power conditioner 21 via the circuit elements C6, D7, and L6 described above, thereby supplying a charging current to the capacitor C4 in the power conditioner 21. .
[0016]
That is, since the power generation output of the solar cell 1 is zero at the start of the snow melting operation, the capacitor C4 is in an uncharged state. In such a non-charged state, a large charging current flows to the capacitor C4 via the system side switch 2e due to the start of the snow melting operation, causing damage to the system side switch 2e as described above. Therefore, when the snow melting operation is started, the AC / DC converter 22 supplies a charging current to the capacitor C4 to charge the capacitor C4. Thus, when the power conditioner 21 performs a snow melting operation, the capacitor C4 is already charged, so that a large charging current does not flow through the system side switch 2e. Here, the power supply for the second control device 2h in the AC / DC converter 22 is not shown.
[0017]
The AC / DC converter 22 can also function as a starting voltage applying circuit that supplies a starting voltage to the power conditioner 21 by supplying a charging current to the capacitor C4 in the power conditioner 21. This is because if the solar cell 1 has no power generation output due to snow accumulation, the power conditioner 21 cannot start the snow melting operation. Therefore, when starting the snow melting operation, power is supplied to the power conditioner 21.
[0018]
The AC / DC converter 22 does not supply the charging current to the power conditioner 21 but may function as a heating current supply circuit that directly supplies the solar cell 1 with a heating current for melting snow. . In this case, in the second control device 2h in the AC / DC converter 22, it is preferable to control the switching operation of the transistor TR7 to step up / down the output of the second system power supply 3b.
[0019]
Thus, in the first embodiment, at the start of snow melting, even if the power generation output of the solar cell 1 is zero, the start can be smoothly performed.
[0020]
(Embodiment 2)
The power supply control device according to the second embodiment of the present invention includes a snow cover state detection unit, a normal control function for AC conversion of the power generation output of the solar cell, and a system power supply to supply a heating current to the solar cell. And a power supply control device main body including a power conditioner that controls at least the start of the snow melting operation by the output of the snow accumulation state detection means. Can smoothly start even if the power generation output of the solar cell is zero.
[0021]
Hereinafter, the power supply control apparatus according to the second embodiment of the present invention will be described with reference to FIG. In FIG. 4, parts corresponding to those shown in FIG. 1 according to the first embodiment are given the same reference numerals, and detailed descriptions of the parts related to the same reference numerals are omitted. 4 includes the power conditioner 21 and the AC / DC converter 22 shown in FIGS. 1 to 3.
[0022]
In Embodiment 2 shown by FIG. 4, the temperature sensor 4 which detects the surface temperature of the solar cell 1 is provided as a snowy state detection means. The temperature sensor 4 is connected to the first control device 2f of the power conditioner 21 and the second control device 2h of the AC / DC converter 22 in the power supply control device main body 2a. Each of the control devices 2f and 2h calculates the output signal of the temperature sensor 4, and by the calculation, in the first control device 2f, when the temperature of the solar cell 1 is equal to or higher than the set value, the snow melting operation is stopped and the set value is set. When the temperature is less than the value, the control is performed so as to start the snow melting operation. When the value is less than the set value, the second control device 2h starts the operation so as to supply the charging current to the capacitor C4 of the power conditioner 21. That is, when the temperature of the solar cell 1 is equal to or higher than the set value, the power conditioner 21 stops the snow melting operation and waits for the snow to naturally melt, and when the temperature is less than the set value, the snow melting operation is performed. In the / DC converter 22, when the temperature of the solar cell 1 becomes lower than the set value, the charging current is supplied to the capacitor C4 of the power conditioner 21. In this case, the first control device 2f of the power conditioner 21 and the second control device 2h of the AC / DC converter 22 are linked to each other so that the snow melting operation is started after the charging of the capacitor C4 is completed to a required value. It has become. In FIG. 4, the first and second system power sources 3a and 3b are simply shown as a snow melting power source (hereinafter the same), and the solar cell 1 and the power supply control device body 2a are connected by a snow melting wire. Shown in state.
[0023]
As described above, according to the second embodiment, when the temperature of the solar cell 1 is equal to or higher than the predetermined temperature by the output signal of the temperature sensor 4, the snow melting operation is stopped because the snow on the solar cell 1 is naturally melted. As a result, useless consumption of the system power supply 3 which is a power supply for snowmelting can be reduced, which can contribute to a reduction in electricity charges.
[0024]
In addition, although the above-mentioned temperature sensor 4 detected the surface temperature of the solar cell 1, you may make it detect the outside temperature instead of the surface temperature, and may perform the above-mentioned operation | movement by this.
[0025]
(Embodiment 3)
In the third embodiment of the present invention, the snow cover state detection means in the second embodiment described above is the temperature sensor 4, but not the temperature sensor 4, for example, as shown in FIG. The illuminating lamp 6 is used as a snow condition detection means. That is, first, in the daytime, even if there is no illuminating lamp 6, it is possible to determine the presence or absence of power generation of the solar cell 1 or decrease in the power generation output by sunlight, and the snow melting state can be detected from the determination. However, since there is no sunlight at night, such a determination cannot be made. Therefore, in the third embodiment, at night, the illumination lamp 6 is turned on to illuminate the solar cell 1 and the output of the illumination lamp 6 is input to the power supply control device main body 2a. Then, in the power supply control device main body 2a, if there is no snow on the solar cell 1, it can be determined that there is no snow because the solar cell 1 generates power with the illumination light of the illumination lamp 6, and there is snow. In this case, it is possible to determine that there is snow because the solar cell 1 cannot generate power even when there is illumination light from the illumination lamp 6. In this case, it is convenient if the illumination lamp 6 can be automatically turned on at night. First, in the power supply control device main body 2a, it is night when the solar cell 1 does not generate power regardless of the presence or absence of snow. The lighting lamp 6 is turned on, and even when the lighting lamp 6 is turned on, it can be determined that there is snow when the solar cell 1 does not generate power, and there is no snow when power is generated, and snow melting is controlled according to this determination. For the user, it is convenient that snow melting is automatically started regardless of daytime or nighttime.
[0026]
(Embodiment 4)
In the fourth embodiment of the present invention, the snowy state detection means in the above-described second embodiment is the temperature sensor 4 instead of the temperature sensor 4 as shown in FIG. The illuminometer 7 provided nearby is used as a snow condition detection means. That is, in Embodiment 4, the amount of sunlight with respect to the solar cell 1 is measured from the output of the illuminance meter 7, and the presence or absence of snow on the solar cell 1 is determined from the difference between the measured amount of sunlight and the amount of power generated by the solar cell 1. If it is determined that there is snow, a snow melting operation is started. This is convenient for the user because the snow melting operation is automatically started.
[0027]
(Embodiment 5)
In the fifth embodiment of the present invention, the snow state detection means in the above-described second embodiment is the temperature sensor 4 instead of the temperature sensor 4 as shown in FIG. A pair of optical sensors arranged opposite to each other is used as a snowy state detection means. That is, in the fifth embodiment, if one of the light sensors is the light emitter 8A and the other light sensor is the light receiver 8B, and there is snow on the solar cell 1, light emitted from the light emitter 8A is shielded by the snow. Since the light receiving body 8B does not receive light, the output level of the light receiving body 8B decreases. If there is no snow on the solar cell 1, the light emitted from the light emitter 8A is not shielded by the snow and is received by the light receiver 8B, so the output level of the light receiver 8B increases. The power supply control device main body 2a receives the output from the photoreceptor 8B, determines the presence or absence of snow from the output level of the photoreceptor 8B, starts the snow melting operation when determining that there is snow, and determines that there is no snow Stops snow melting. This is convenient for the user because the snow melting operation is automatically started.
[0028]
Such an optical sensor includes an infrared sensor and other sensors, but may be any sensor that can detect the presence or absence of a shielding object. In the fifth embodiment, when the output of the sensor is lost, the snow melting operation is not stopped immediately when the snow on the solar cell 1 is melted, but the snow melting operation may be continued for a certain period of time. Further, in the case of nighttime, it is of course possible to reduce wasteful power consumption due to the snow melting operation in combination with the above embodiment.
[0029]
(Embodiment 6)
In the sixth embodiment of the present invention, the snow condition detection means in the above-described second embodiment is the temperature sensor 4, but the weather forecast information is provided as shown in FIG. The destination 9 and the power supply control device main body 2a are connected by a telephone line, and the weather forecast from the destination 9 is used as a snow cover state detection means.
[0030]
Since the weather forecast includes information such as a snowfall state or a snow cover state, the snow cover state on the solar cell 1 can be determined. In this case, if the data from the provider 9 is processed into a form that can be processed by the power control device main body 2a, the power control device main body 2a can automatically start the snow melting operation. If it is not, the snow melting operation can be automatically started by enabling the information to be processed in the power supply control device main body 2a. Alternatively, the user may activate the power supply control device main body 2a based on the information.
[0031]
(Embodiment 7)
In the seventh embodiment of the present invention, the snow condition detection means in the second embodiment is the temperature sensor 4 instead of the temperature sensor 4 as shown in FIG. The barometer 11 is used as a snow condition detection means.
[0032]
In the seventh embodiment, the outside air temperature by the thermometer 10 and the atmospheric pressure by the barometer 11 are input to the power supply control device main body 2a. The power supply control device main body 2a predicts snowfall from the outside air temperature and the atmospheric pressure, and starts snowmelt operation so as to avoid the accumulation of snow on the solar cell 1 when predicting that there is snowfall. Therefore, according to the seventh embodiment, since the snow melting operation is performed only when it snows, it can be reduced with useless power consumption, and the snow melting operation can be automatically started.
[0033]
(Embodiment 8)
The power supply control device according to the eighth embodiment of the present invention has a normal control function for AC-converting the power generation outputs of several solar cell strings and a system power supply to supply a heating current to the solar cell to melt snow. A power conditioner provided with a control function for power generation, a power generation current detecting means for individually detecting a power generation current of each of the solar cell strings, and each of the solar cell strings and the power conditioner. The power generation amount of each of the solar cell strings is calculated from the output state of each of the plurality of switches and each of the generated current detection means, and which solar cell string has snow on the basis of the calculated power generation amount And microcomputer means for controlling to close the switch corresponding to the solar cell string determined to have snow. Are those, by starting the only snow-melting operation on the solar cell string having the snow, it has been possible to reduce wasteful power consumption.
[0034]
Hereinafter, a solar power generation system including a power supply control device according to Embodiment 8 of the present invention will be described with reference to FIG. 10. Reference numeral 1 denotes a solar battery, and 2 denotes a power supply control device according to Embodiment 8. The solar cell 1 is composed of a plurality of solar cell strings 1a, 1b, 1c. The power supply control device 2 includes a power conditioner 21 and current sensors 12a... Individually corresponding to the solar cell strings 1a, 1b, and 1c as generated current detection means. 12b. 12c, switches 14a, 14b, 14c connected in parallel to the respective backflow prevention diodes 13a, 13b, 13c corresponding to the solar cell strings 1a, 1b, 1c, respectively, and microcomputer means 15 It is comprised. The microcomputer means 15 calculates the power generation amount of each of the solar cell strings 1a, 1b, 1c from the output state of each of the current sensors 12a, 12b, 12c, and any solar cell from the calculated power generation amount. It is determined whether or not there is snow on the strings 1a, 1b, and 1c. And it controls so that the switch 14a, 14b, 14c corresponding to the solar cell string 1a, 1b, 1c determined to have snow accumulation from this determination may be closed, and to input a snow melting command to the power conditioner 21 It has become. In addition, although 14a, 14b, and 14c were switches, you may be a switching element.
[0035]
In this case, since the solar cell strings 1a, 1b, and 1c have no power generation due to snow, they need to be distinguished from each other because there is no power generation even in the shade of trees. In this case, in the eighth embodiment, when the power generation amount is recorded regularly, for example, every day, and when the specific time zone of the day is a sunny day, the power generation amount is reduced periodically in the same manner. Is determined to be, for example, a tree shade. When the power generation amount decreases unspecified, it is determined that the snow cover is different from the tree shadow, and the snow melting operation is started only when it is determined that the snow cover.
[0036]
As described above, according to the eighth embodiment, it is not necessary to perform a snow melting operation on all of the solar cell strings 1a, 1b, and 1c, and a snow melting operation is performed only on a specific solar cell string that has accumulated snow. There is an advantage that power is not consumed wastefully.
[0037]
【The invention's effect】
As described above, according to the present invention, the snow melting operation by the power conditioner can be smoothly started without wasteful power consumption.
[Brief description of the drawings]
FIG. 1 is a circuit block diagram of a photovoltaic power generation system incorporating a power supply control device according to Embodiment 1 of the present invention. FIG. 2 is a detailed circuit diagram of a power conditioner in the power supply control device of FIG. 1 is a detailed circuit diagram of an AC / DC converter in the power supply control apparatus of FIG. 1. FIG. 4 is a circuit block diagram of a photovoltaic power generation system in which the power supply control apparatus according to Embodiment 2 of the present invention is incorporated. FIG. 6 is a circuit block diagram of a photovoltaic power generation system in which a power supply control device according to Embodiment 3 of the present invention is incorporated. FIG. 6 is a circuit block diagram of a photovoltaic power generation system in which a power supply control device according to Embodiment 4 of the present invention is incorporated. FIG. 7 is a circuit block diagram of a solar power generation system in which a power supply control device according to Embodiment 5 of the present invention is incorporated. FIG. 8 is sunlight in which a power supply control device according to Embodiment 6 of the present invention is incorporated. Power generation system FIG. 9 is a circuit block diagram of a photovoltaic power generation system in which the power supply control device according to Embodiment 7 of the present invention is incorporated. FIG. 10 is a circuit diagram of the power supply control device according to Embodiment 8 of the present invention. Circuit block diagram of built-in photovoltaic power generation system [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Solar cell 2 Power supply control apparatus 2a Power supply control apparatus main body 3 System power supply 21 Power conditioner 22 AC / DC converter

Claims (2)

It is connected between the solar cell and the system power supply.
A normal control function for AC conversion of the power generation output of the solar cell;
A power conditioner having a control function for processing the output of a system power source connected to the system side switch and supplying a heating current to the solar cell to melt snow;
Charging current supply means for supplying a charging current to a capacitor in the power conditioner when the power conditioner starts snow melting control;
A power supply control device comprising: It is connected between the solar cell and the system power supply.
A normal control function for AC conversion of the power generation output of the solar cell;
A power conditioner having a control function for processing the output of a system power source connected to the system side switch and supplying a heating current to the solar cell to melt snow;
A starting voltage applying circuit for applying a starting voltage to the power conditioner by supplying a charging current to a capacitor in the power conditioner;
A power supply control device comprising:

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