JPH10271860A - Method for controlling snow melting device using solar battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily efficiently control a bidirectional power conditioner, by supplying DC power to solar batteries after the power conditioner is started and, when the DC power reaches a preset constant power value, automatically stopping snow melting operations. SOLUTION: At the time of starting snow melting operations, electromagnetic contactors 41-43 are closed and DC power is supplied to solar batteries 11, 12, and 13. During the initial stage of the snow melting operations, a power conditioner 61 supplies electric power in a constant-voltage mode and, when the voltages at the solar batteries 11, 12, and 13 drop due to temperature rises in the batteries 11, 12, and 13, the conditioner 61 starts constant-power control. A controller 62 detects this state, stops the forward power rectifying operations, and sets photovoltaic power generation to a standby state. Therefore, the electric power generated by the photovoltaic power generation can be made to flow reversely while sunshine is available and, at the same time, the temperature rises of the solar batteries 11, 12, and 13 can be utilized for melting snow when the snow falls or piles up.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a snow melting device in a solar cell power generation system, and can easily and efficiently control a bidirectional (forward conversion operation and reverse conversion operation) power conditioner. It relates to a control method.

[0002]

2. Description of the Related Art A solar cell generates electric power by converting light energy of sunlight into electric energy by a solar cell. Normally, the power generated by the solar cell is converted from direct-current power to alternating-current power by an inverse conversion operation of a power conditioner, and the power is reversely flowed to the system.

[0003] A snow melting device in a solar cell power generation system is a device that applies an appropriate DC power from the outside to the solar cell and uses it as a heating element to melt snow. Conventionally, a snow melting sensor or the like is installed outdoors. The power conditioner was stopped by this signal.

[0004]

However, there is a drawback that the apparatus becomes complicated due to the necessity of mounting a special snow melting sensor or the like and controlling by this signal. According to the present invention, an appropriate control method of DC power applied to a solar cell is established, and it is detected that snow has melted by monitoring the supplied power.

[0005]

SUMMARY OF THE INVENTION When DC power is applied to a solar cell, the temperature of the solar cell rises, and as a result, the terminal voltage decreases. The power conditioner controls the DC power, and generates heat at a constant voltage when the temperature is low, and supplies a predetermined constant power when the temperature rises. By shifting to the constant power control state, it is determined that the snow on the solar cell has been melted, and the power conditioner is stopped after a certain period of time.

The method for stopping a snow melting apparatus according to the present invention is made possible by performing bidirectional control using a power conditioner of a photovoltaic power generation system, and does not require a special snow melting sensor.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The method for controlling a snow melting apparatus in a solar cell power generation system according to the present invention supplies DC power to a solar cell after starting a power conditioner, and when the DC power reaches a set constant power value. The snow melting operation is automatically stopped, and after the snow melting, the power conditioner returns to a state in which the power conditioner can generate power by the reverse conversion operation by solar power generation.

Actually, the snow melting device of the solar cell is manually activated, and the temperature of the solar cell rises as the snow melts due to the forward conversion operation of the power conditioner, and the voltage decreases as the temperature rises. Due to this decrease in voltage, a larger current tends to flow. The power conditioner controls the supply of the DC power to a constant power, and stops when the power reaches a set constant power state. However,
The device can be manually stopped and started. By doing so, it is possible to eliminate dangerous snow removal work, and it is also advantageous in terms of cost since there is no need to add large parts from the conventional system interconnection system.

[0009]

FIG. 1 shows an embodiment of the present invention, and illustrates a main circuit of a solar cell snow melting apparatus.

As shown in FIG. 1, a power conditioner 61 is a main device of a snow melting apparatus, and performs an inverse conversion operation of reversely flowing power generated by a solar cell to a system, and applies power from the system to the solar cell during snow melting. Perform a forward conversion operation. Control device 6
2 outputs commands for the forward conversion operation and the reverse conversion operation. Normally, electric power is transmitted from the solar cells (11 to 13) to the power conditioner 61 through the backflow prevention diodes (21 to 23). Further, a series circuit of the resistors (31-33) and the electromagnetic contactors (41-43) is connected in parallel to the backflow prevention diodes (21-23), and the resistors (31-33) are connected.
Are used to balance the current flowing through the solar cells (11 to 13), and are used in the electromagnetic contactors (41 to 43) during the snow melting operation.
Is closed, and DC power is supplied to the solar cell. The DC current detector 71 is means for detecting the current when snow melts, and the AC current detector 81 is used for constant power control.

FIG. 2 shows an example in which the electromagnetic contactor 41 connected in parallel to the backflow prevention diodes (21 to 23) is collectively controlled without being provided in each solar cell string in the same manner.

To start the snow melting apparatus, the manual switch 01 is turned on to the snow melting side. Thereby, the control device 62 starts the power conditioner 61 by the forward conversion operation.
In this case, the electromagnetic contactors (41 to 43) are closed, and DC power is supplied to the solar cells (11 to 13) via the current limiting resistors (31 to 33). At the beginning of the snow melting operation, the power conditioner 61 supplies power in the constant voltage mode.
When the voltage decreases due to a rise in the temperature of the solar cell, the power conditioner 61 enters constant power control. The control device 62 detects this state and stops the forward conversion operation of the power conditioner 61. After the stop, the apparatus enters a standby state so that solar power can be generated. If it is necessary to perform the snow melting operation again, the manual switch 01 is turned ON to the snow melting side. If it is desired to stop the snow melting mode halfway, the manual switch 01 is turned off.

FIG. 3 shows the characteristics of the control state.
At start-up, the operation starts from a constant voltage state, and shifts to a constant power state when the temperature of the solar cell rises. The device also has a constant current control function to prevent overcurrent from flowing into the solar cell.

FIG. 4 shows the configuration of the control circuit. The control device 62 of the power conditioner includes a switching circuit 101 for a forward conversion and an inverse conversion operation in a control circuit for a conventional grid connection operation.
And DC voltage control circuit 102, DC current control circuit 10
3. A DC power control circuit 104 is added.

[0015]

When a solar power generation system is installed in a snowfall area, it becomes difficult to remove snow from a sloping roof. Particularly in a private house, the surface of a solar cell is slippery, and it is dangerous to climb the roof. According to the present invention, at the same time as performing a reverse flow of electric power by solar power generation during conventional sunshine, it is possible to have a function capable of performing a forward conversion operation of a power conditioner at the time of snowfall and snowfall, and melting snow due to a rise in temperature of a solar cell, result,
Features that eliminate dangerous snow removal work. In addition, the circuit system does not require a large addition of components to the conventional system interconnection system, and is in a range that can be realized in terms of cost.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of a method for controlling a snow melting apparatus according to the present invention.

FIG. 2 is a circuit diagram showing another embodiment of the method for controlling the snow melting apparatus of the present invention.

FIG. 3 is an output characteristic diagram of a power conditioner during a forward conversion operation during a snow melting operation.

FIG. 4 is a diagram showing a configuration of a control device.

[Explanation of symbols]

 01 Manual switch (start / stop of snow melting operation) 11-13 Solar cell 21-23 Backflow prevention diode 31-33 Current limiting resistor 41-43 Magnetic contactor 61 Power conditioner 62 Control device 71 DC current detector 81 AC current detection Unit 101 Switching circuit for reverse conversion operation 102 DC voltage control circuit 103 DC current control circuit 104 DC power control circuit

Continuing on the front page (72) Inventor Kiyoshi Kinoshita 3-12-15 Wakaoji, Amagasaki-shi, Hyogo Sonoda Keiki Kogyo Co., Ltd. Within Nippon Battery Co., Ltd.

Claims (1)

[Claims] 1. A solar cell module comprising: a plurality of solar cell modules connected in series; a plurality of sets of solar cell strings each having a backflow prevention diode provided at an output thereof; In addition, when the snow on the solar cell melts, the inverter performs a forward conversion operation, and supplies DC power to the solar cell through a series circuit of a contactor and a resistor connected in parallel with the backflow prevention diode. In a device that heats and melts a solar cell, a forward converter that supplies DC power to the solar cell has a function of controlling a DC constant voltage and a constant power, and after a certain period of time after the constant power control function operates. A method for controlling a snow melting apparatus using a solar cell, wherein the forward conversion operation is stopped.