JP2012228062A - Power conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power conditioner capable of suppressing degradation in the conversion efficiency of the power conditioner without need for cleaning a filter.SOLUTION: The power conditioner includes: a housing; an inverter that is disposed in the housing and converts DC power generated at a solar cell into AC power; a ventilation fan disposed in the housing; and a filter that is disposed at a position corresponding to the ventilation fan in the housing. The ventilation fan can implement forward rotation and reverse rotation, and the forward rotation ventilates the inside of the housing and reverse rotation removes dust adhering to the filter.

Description

  The present invention relates to a power conditioner.

  The solar power generation system mainly includes a plurality of solar cell modules disposed on the roof, a junction box that combines the wiring from the plurality of solar cell modules and supplies the DC power to the power conditioner, It is configured by a power conditioner that converts DC power from the connection box into AC power and links the AC power to the system power supply. The junction box and the power conditioner incorporate various electronic circuits such as a booster circuit and an inverter circuit.

  The various electronic circuits built into this inverter will increase in temperature when the system is operating, so it is necessary to lower the temperature by installing a ventilation fan and lowering the temperature of the surrounding air by ventilating the surrounding air. There is. Further, in order to prevent dust from being mixed with the air ventilated by the ventilation fan, it is necessary to provide a filter in the vicinity of the ventilation fan.

  In Patent Document 1, in a photovoltaic power generation power conversion device, a DC reactor, an AC reactor, and a ventilation fan are provided in a ventilation path that penetrates the casing, and filters are provided at both ends of the ventilation path. It is described. Thereby, according to patent document 1, since the external air attracted | sucked by a fan passes only both reactors and does not pass electric equipment parts other than both reactors, the deterioration by the external air of the electrical equipment parts is prevented, and an inexpensive fan, It is said that a power converter can be made small using a filter.

JP 2000-152655 A

  However, in the structure described in Patent Document 1, dust tends to adhere to the filter provided on the suction side of the ventilation fan. When a large amount of dust adheres to the filter and becomes clogged, the amount of outside air sucked into the ventilation path tends to decrease. When the amount of outside air sucked into the ventilation path decreases, the temperature inside the ventilation path rises, adversely affects electrical equipment parts (for example, semiconductor switch elements and capacitors) other than both reactors, and conversion of the power converter Efficiency may be reduced. Further, if the temperature rises and exceeds the allowable temperature of the component, the component may be broken or destroyed, and the power conversion device may be broken. Therefore, the user has to check the filter on a daily basis and clean the filter, which is complicated.

  This invention is made | formed in view of the above, Comprising: It aims at obtaining the power conditioner which can suppress the fall of the conversion efficiency of a power conditioner, without cleaning a filter.

  In order to solve the above-described problems and achieve the object, a power conditioner according to one aspect of the present invention is provided with a casing, and the DC power generated in the solar cell is converted into AC power. Inverter, a ventilation fan disposed in the housing, and a filter disposed at a location corresponding to the ventilation fan in the housing, the ventilation fan being capable of forward and reverse rotation The interior of the housing is ventilated by performing forward rotation, and the dust attached to the filter is removed by performing reverse rotation.

  ADVANTAGE OF THE INVENTION According to this invention, when the ventilation fan performs normal rotation, the temperature rise of the air in a housing | casing can be suppressed and the fall of the power conversion efficiency by an inverter can be suppressed. Further, since the ventilation fan performs reverse rotation, dust attached to the filter is removed during the forward rotation of the ventilation fan, so that the necessity of cleaning the filter can be reduced. That is, it is possible to suppress a decrease in the conversion efficiency of the power conditioner without cleaning the filter.

FIG. 1 is a diagram illustrating a configuration of a power conditioner according to an embodiment. FIG. 2 is a flowchart showing the control of the ventilation fan according to the embodiment. FIG. 3 is a diagram illustrating an operation at the time of reverse rotation of the ventilation fan according to the embodiment. FIG. 4 is a diagram illustrating an operation during normal rotation of the ventilation fan according to the embodiment.

  Embodiments of a power conditioner according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment.
A power conditioner 1 according to an embodiment will be described with reference to FIG. FIG. 1 is an exploded perspective view showing the configuration of the power conditioner 1.

  The power conditioner 1 adjusts DC power generated by a solar cell (not shown) and supplies it to AC system power (not shown). Specifically, the power conditioner 1 includes a housing 10, an inverter 20, a relay 30, a ventilation fan 40, a filter 50, an internal timer 60 (clocking means, not shown), and a control circuit 70.

  The housing 10 accommodates, for example, an inverter 20, a relay 30, a ventilation fan 40, an internal timer 60, and a control circuit 70 therein. The housing 10 has, for example, a box-shaped outer shape, and is formed of, for example, a conductor. For example, a filter 50 is disposed on the front surface 10a of FIG.

  The inverter 20 is disposed in the housing 10. The inverter 20 converts DC power generated by a solar cell (not shown) into AC power. The inverter 20 includes, for example, a plurality of switching elements, and converts DC power into AC power according to an on / off pattern of the plurality of switching elements. Although each switching element is a heat-generating component that generates a large amount of heat during operation, power conversion efficiency is reduced in a high-temperature environment. Therefore, sufficient cooling is required to protect the switching element itself from overheating.

  When the solar cell is in a power generation state and the power conditioner 1 performs an operation of converting DC power from the solar cell into AC power, an electronic circuit (for example, the inverter 20 or the reactor) built in the power conditioner 1 generates heat. As a result, the temperature of the air in the housing 10 rises. Therefore, in order to lower the temperature of the air in the housing 10, the ventilation fan 40 is rotated forward as shown in FIG. FIG. 4 is a diagram illustrating the operation of the ventilation fan 40 during forward rotation.

  That is, the ventilation fan 40 is arranged in the housing 10. The ventilation fan 40 can rotate forward and backward. The ventilation fan 40 is disposed, for example, at a location corresponding to the inverter 20 in the housing 10. The ventilation fan 40 is disposed, for example, at a location where the blowout side of the ventilation fan 40 becomes the inverter 20 when performing normal rotation, that is, a location between the inverter 20 and the surface 10 a of the housing 10. The ventilation fan 40 ventilates the inside of the housing 10 by performing forward rotation.

  A filter for removing dust is provided at an air intake port of the ventilation fan 40. This is to prevent dust outside the power conditioner 1 from entering the housing 10 and adhering to a built-in electronic circuit (for example, the inverter 20 or the control circuit 70) when air is taken in. .

  That is, the filter 50 is arranged at a location corresponding to the ventilation fan 40 in the housing 10. For example, the filter 50 is disposed on the surface 10 a of the housing 10 that is on the suction side of the ventilation fan 40 when the ventilation fan 40 rotates in the forward direction.

  However, if the ventilation fan 40 is continuously operated in the normal rotation, if the dust adheres to the filter 50 and is left as it is, the filter 50 becomes clogged.

  Therefore, the ventilation fan 40 performs a reverse rotation operation as shown in FIG. 3 to remove dust adhering to the filter 50 by reversing the air flow. That is, the ventilation fan 40 removes dust adhering to the filter 50 by performing reverse rotation. FIG. 3 is a diagram illustrating the operation of the ventilation fan 40 during reverse rotation.

  The reverse rotation operation of the ventilation fan 40 may be performed by manual switch operation, or may be performed by switching control by the control circuit 70. For example, the control circuit 70 controls the internal timer 60 to measure the elapsed time from the completion of the previous reverse rotation operation of the ventilation fan 40. When the elapsed time from the completion of the previous reverse rotation operation reaches the first threshold value, for example, the control circuit 70 stops the normal rotation operation of the ventilation fan 40 and starts the reverse rotation operation of the ventilation fan 40. Let Alternatively, for example, when the ventilation fan 40 has already stopped, the reverse rotation operation of the ventilation fan 40 is started.

  At this time, the control circuit 70 controls the internal timer 60 to measure the operation time of the reverse rotation operation of the ventilation fan 40. When the operation time of the reverse rotation operation reaches the second threshold, the control circuit 70 stops the reverse rotation operation of the ventilation fan 40 and starts the forward rotation operation of the ventilation fan 40, for example. Alternatively, for example, when the forward rotation operation of the ventilation fan 40 should not be started, the reverse rotation operation of the ventilation fan 40 is stopped. In this way, the ventilation fan 40 can perform a reverse rotation operation for a certain period of time every time a certain period of time elapses using the internal timer 60 of the power conditioner 1. Thereby, even if a user does nothing, the filter 50 can be automatically cleaned regularly.

  It is also possible to set the timing for performing the reverse rotation operation at night when the solar cell does not generate power, that is, when the power conditioner 1 does not operate the inverter 20.

  If the ventilation fan 40 is reversely rotated while the solar cell is generating sufficient DC power, the operation of the inverter 20 and the operation of the ventilation fan 40 (forward rotation) are first stopped. Next, the reverse rotation operation of the ventilation fan 40 is started. Further, the inverter 20 is stopped during the reverse rotation operation of the ventilation fan 40, and even if the solar cell generates sufficient DC power, it cannot be used effectively.

  On the other hand, in the embodiment, for example, the ventilation fan 40 performs reverse rotation at night when the solar cell does not generate power. During the night when the inverter 20 is not operated, the inverter 1 is not in operation, so the ventilation fan 40 does not need to rotate forward for cooling. The reverse rotation operation can be performed without wasting power to be used.

  In addition, since the solar cell does not generate power at night, the power for operating the ventilation fan 40 uses grid power. For example, a converter (not shown) converts system power into DC power and supplies it to the ventilation fan 40. In addition, the relay 30 connects the alternating current power converted by the inverter 20 to alternating current system electric power (not shown) in the time slot | zone when the solar cell is generating electric power. For example, the relay 30 supplies the AC power converted by the inverter 20 to the distribution board of the system power.

  Alternatively, in the embodiment, as the timing for performing the reverse rotation operation, the solar cell is generating power, but the inverter 1 for converting from direct current to alternating current in the power conditioner 1 is selected to select a time zone in which the generated power is low. Is also possible. This is the time zone before dawn or sunset, for example.

  That is, in this time zone, the power conditioner 1 is stopped and the solar cell is also generating power. Therefore, the surplus power generated by the solar cell can be used as power for operating the ventilation fan 40 without using system power, which is economical.

  At this time, the flow of control of the ventilation fan 40 in the power conditioner 1 is, for example, as shown in FIG. FIG. 2 is a flowchart showing a control flow of the ventilation fan 40.

  In step S1, the control circuit 70 determines whether or not the solar cell output level is sufficient for the inverter 20 to operate at the start of photovoltaic power generation. That is, the control circuit 70 receives a signal indicating the solar cell output level from a voltage sensor (not shown) that detects the solar cell output level, and determines whether the solar cell output level is greater than or equal to the third threshold value. For example, the third threshold value is experimentally obtained in advance as a voltage level that allows the inverter 20 to operate. The control circuit 70 advances the process to step S3 when the solar cell output level is equal to or higher than the third threshold, and advances the process to step S2 when the solar cell output level is lower than the third threshold.

  In step S <b> 2, the control circuit 70 controls the ventilation fan 40 to perform the reverse rotation operation of the ventilation fan 40. For example, since the dawn when solar power generation starts is not a solar cell output at a level at which the inverter 20 can be operated, the ventilation fan 40 performs a reverse rotation operation as shown in FIG. At that time, the electric power of the ventilation fan 40 uses electric power from a solar cell.

  In step S <b> 3, the control circuit 70 controls the ventilation fan 40 to perform the normal rotation operation of the ventilation fan 40. For example, during the time when the inverter 20 can be operated and the AC power is output, the ventilation fan 40 operates in a forward rotation as shown in FIG. As the ventilation fan 40 rotates forward as shown in FIG. 4, dust adheres to the filter 50 provided in the vicinity of the ventilation fan 40.

  In step S4, it becomes the evening when a solar cell output falls, and the output of the inverter 20 falls.

  In step S <b> 5, the control circuit 70 determines whether or not the solar cell output level is sufficient to allow the inverter 20 to be operated at the start of photovoltaic power generation. That is, the control circuit 70 receives a signal indicating the solar cell output level from a voltage sensor (not shown) that detects the solar cell output level, and determines whether the solar cell output level is greater than or equal to the third threshold value. If the solar cell output level is greater than or equal to the third threshold value, the control circuit 70 proceeds to step S3. If the solar cell output level is less than the third threshold value, the control circuit 70 proceeds to step S6.

  In step S6, the control circuit 70 controls the ventilation fan 40 to perform the reverse rotation operation of the ventilation fan 40. For example, in the time zone before sunset, the solar cell output decreases and the inverter 20 cannot be operated. The ventilation fan 40 performs the reverse rotation operation of FIG. 3 again to remove dust attached to the filter 50. As a result, dust is less likely to adhere to the filter 50, so that stable output can be provided without daily care.

  As described above, in the embodiment, in the power conditioner 1, the ventilation fan 40 ventilates the inside of the housing 10 by performing normal rotation. Thereby, the temperature rise of the air in the housing | casing 10 can be suppressed and the fall of the power conversion efficiency by the inverter 20 can be suppressed. The ventilation fan 40 removes dust attached to the filter 50 by performing reverse rotation. Thereby, since the dust adhering to the filter 50 is removed at the time of forward rotation of the ventilation fan 40, the necessity of cleaning the filter can be reduced. That is, it is possible to suppress a decrease in conversion efficiency of the power conditioner 1 without cleaning the filter.

  Further, in the embodiment, the ventilation fan 40 can perform the reverse rotation operation for a certain period of time every time a certain period elapses by using the internal timer 60. Thereby, even if a user does nothing, the filter 50 can be automatically cleaned regularly.

  In the embodiment, the ventilation fan 40 performs reverse rotation using the system power at night when the solar cell does not generate power. That is, since the inverter 1 is not in operation at night when the inverter 20 is not operated, the ventilation fan 40 does not need to rotate forward for cooling. The reverse rotation operation can be carried out without wasting the generated electric power.

  In the embodiment, the ventilation fan 40 reversely rotates using the DC power generated by the solar battery in a time zone in which the value of the DC power generated by the solar battery is smaller than the operable value of the inverter 20. I do. Therefore, surplus electric power generated by the solar cell can be used as electric power for operating the ventilation fan 40 without using system electric power, so that the power conditioner 1 can be operated more economically.

  In FIG. 1, one ventilation fan 40 is shown, but a plurality of ventilation fans 40 may be provided for one filter 50 as shown in FIGS. 3 and 4.

  As described above, the power conditioner according to the present invention is useful for conversion of electric power generated in a solar cell.

DESCRIPTION OF SYMBOLS 1 Power conditioner 10 Case 20 Inverter 30 Relay 40 Ventilation fan 50 Filter 60 Internal timer 70 Control circuit

Claims (4)

A housing,
An inverter arranged in the housing and converting DC power generated by the solar cell into AC power;
A ventilation fan arranged in the housing;
A filter disposed at a location corresponding to the ventilation fan in the housing;
With
The ventilation fan is capable of normal rotation and reverse rotation, ventilates the inside of the housing by performing normal rotation, and removes dust adhering to the filter by performing reverse rotation. Conditioner. Further comprising time measuring means for measuring the time during which the ventilation fan is rotating in reverse,
The power conditioner according to claim 1, wherein the ventilation fan performs reverse rotation for a predetermined time using the time measuring unit. The power conditioner according to claim 1 or 2, wherein the ventilation fan performs reverse rotation using grid power at night when the solar cell does not generate power. The ventilation fan performs reverse rotation using the DC power generated by the solar cell in a time zone in which the value of the DC power generated by the solar cell is smaller than the operable value of the inverter. The power conditioner according to claim 1 or 2.

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