JPH09243136A - Solar air conditioner - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] A room air conditioner system with a small control circuit, which effectively utilizes the generated power of a solar cell to improve the utilization rate and speed up the recovery of initial costs. SOLUTION: A room air conditioner provided with an inverter circuit 10 to which electric power obtained by converting alternating current from a commercial power source 1 into direct current by a rectifying circuit 24 and direct current power from a solar cell 9 are supplied, and power is generated by the solar cell 9. Generated power to room air conditioner 2
DC / DC converter 1 controlled according to 0 load condition
2 and an inverter 10 that sells power to a power company when the power generated by the solar cell 9 is surplus.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a room air conditioner system that uses a commercial power source and a solar cell in combination.

[0002]

2. Description of the Related Art In recent years, systems for effectively utilizing electric power generated by solar cells have been put to practical use. Solar cells have recently attracted particular attention as a clean energy source, but their capacity changes depending on the illuminance of sunlight, and because they are current-type cells, the generated power decreases when they are overloaded. There are problems and how to use them is one of the major issues.

However, from the background of increasing demand for electric power and the like, the application of the power source as an auxiliary power source for room air conditioners and the like, which consumes a large amount of power, has been actively studied. For example, Sanyo Electric Co., Ltd., August 1991. The solar air conditioner has been commercialized since it was announced in the newspaper. This specification is a home-use solar air conditioner that connects a solar cell with a maximum output of 500 W and one air conditioner. Solar cell is 500W
Because of the output, when the power consumption of the air conditioner exceeds the solar cell output, the solar cell and commercial AC power supply are used together for operation. The interface circuit that connects the output from the solar cell to the air conditioner is connected to a DC / DC converter circuit, and employs a maximum power sampling method that preferentially uses the output from the solar cell. In addition, the conventional example of this type is the actual development 62-
There is a 95224 publication.

[0004]

As described above, the solar air conditioner of Sanyo Electric is a home-use solar air conditioner in which a solar battery having a maximum output of 500 W and one air conditioner are connected, and the user operates the air conditioner. Unless it is not, the power generated by solar power is not used. Therefore, there is a problem that the utilization rate is low and it takes a great number of years to recover the initial cost.

Recently, due to the development of solar cells,
Those of 00W or more are becoming popular. At this time, the problem of surplus power comes out, but in the conventional example, this point has not been disclosed yet.

[0006]

According to the present invention, an inverter circuit is supplied with electric power obtained by converting alternating current from a commercial power source into direct current by a rectifier circuit, and direct current power from a solar cell, and controlled by the inverter circuit. DC / DC for controlling the electric power generated by the solar cell according to the load state of the room air conditioner in a room air conditioner equipped with a compressor
A converter is provided integrally with the room air conditioner, and an inverter is provided in the commercial power supply system.

Specifically, the inverter and the DC / DC and converter connected to the commercial power supply system have operation control means, and the maximum output operating point for obtaining maximum generated power from the solar cell by the operation means. The voltage can be set.

The DC / DC converter sets a limit value when supplying electric power generated by a solar cell to a room air conditioner,
When the power generated by the solar cell is less than the limit value and the load on the room air conditioner is higher than the power generated by the solar cell, the power generated by the solar cell is maximized to supply power to the room air conditioner. When the load on the room air conditioner is equal to or higher than the limit value and the load on the room air conditioner is equal to or higher than the limit value, the power generated by the solar cell equivalent to the limit value is supplied to the room air conditioner. When the load on the room air conditioner is higher than the load on the room air conditioner, the generated power of the solar cell equivalent to the load on the room air conditioner is supplied to the room air conditioner, and the surplus power is sold to the electric power company via the inverter.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a room air conditioner system provided with a solar cell according to the present invention. 1 is a commercial power source, 9 is a solar cell, 12 is a DC / DC converter with optimum active power control, 16 is an outdoor unit of a room air conditioner for each home, 20 is an indoor unit of a room air conditioner, 2
Reference numeral 4 denotes a rectifier circuit for these room air conditioners. And one
0 is an inverter that works when returning the surplus power generated by the solar cell 9 to the commercial power supply 1 side.

In the figure, in the outdoor unit 16 of the room air conditioner of each home, the power of the commercial power source 1 is converted into direct current by the rectifier circuit 24 and supplied to an inverter (not shown) to drive the compressor motor. Further, the power generated by the solar cell 9 is supplied to the DC / DC converter 12 depending on the operating condition of the room air conditioner, and the power generated by the solar cell 9 according to the load of the room air conditioner is supplied.

Here, the DC / DC converter 12 sets an output power limit value in the DC / DC converter when the power generated by the solar cell 9 is supplied to the outdoor unit 16 of the room air conditioner. As a result, even if the power generated by the solar cell 9 is sufficiently large and the power consumption of the room air conditioner is entirely covered by the power generated by the solar cell 9, only a certain amount of power generated (for example, 500 W) can be supplied to the room air conditioner. . Dare to set the output power limit value, DC / D
This is because the capacitance of each of the C converters 12 can be reduced, the switching transformers, choke coils, power devices, and other main components can be downsized, and general-purpose products can be used, and costs can be reduced. Similarly, the capacity of the inverter 10
For example, the same effect can be obtained by setting the capacity such as 1000 W so that a general-purpose product can be used.

Next, the basic operation of the system in the solar cell 9, the DC / DC converter and the room air conditioner will be described.

When the amount of solar radiation is sufficiently large, that is, when the generated power is sufficiently large, the following two types of control are performed.

When the power generated by the solar cell and the power consumed by the air conditioner are equal to or higher than the output power limit value of the DC / DC converter.

(Solar battery generated power: 1500 W, output power limit value: 500 W, air conditioner power consumption: 1000 W) The solar battery generated power is equal to or higher than the output power limit value of the DC / DC converter, and the air conditioner power consumption is DC / DC converter. If the output power limit value is less than or equal to.

In the case of (solar battery generated power: 1500 W, output power limit value: 500 W, air conditioner power consumption: 300 W), 500 W of solar battery generated power is supplied to the room air conditioner by limiting the output power of the DC / DC converter. , 500 W of the shortage is supplied from the commercial power supply 1, and 1000 W of surplus power is returned to the commercial power supply system via the inverter 10. In the case of, the DC / DC converter is controlled to supply only 300 W of power consumption of the air conditioner,
The surplus power of 1200 W is returned to the commercial power system through the inverter 10 in the same manner as described above.

Next, when the amount of solar radiation is small, the following two controls are performed.

The power generated by the solar cell is less than the output power limit value of the DC / DC converter, and the air conditioner power consumption is D
When the output power limit value of the C / DC converter or more is exceeded.

(Solar battery generated power: 400 W, output power limit value: 500 W, air conditioner power consumption: 1000 W) The solar battery generated power is less than the output power limit value of the DC / DC converter, and the air conditioner power consumption is solar cell generated power. If:

In the case of (solar battery generated power: 400 W, output power limit value: 500 W, air conditioner power consumption: 300 W), the optimum effective power control of the DC / DC converter maximizes the generated power of the solar battery and the room air conditioner. Supply to. The insufficient 600 W is supplied from the commercial power source 1 to the room air conditioner via the rectifier circuit 24.
In this case, the DC / DC converter is controlled to supply only 300 W of power consumption of the air conditioner. Then, the surplus of 100 W is returned to the commercial power circuit via the inverter 10.

Next, the operation of the DC / DC converter will be described with reference to FIG. The figure shows a DC / DC converter 1
2 is a simplified view of the reference numeral 44, where 44 is a voltage detection unit and 4
Reference numeral 5 denotes a primary current detection unit, and 46 denotes a secondary current detection unit.

In this DC / DC converter, the electric power obtained from the voltage-current relationship of the solar cell 9 which is constantly fluctuating depending on the load and the amount of solar radiation is applied to the air conditioner load such as output power limit value and optimum active power control. It is a device that changes the electric power according to the voltage and boosts the output voltage VL to the inverter voltage of the air conditioner or more.

As the output power limit value of the DC / DC converter, the current supplied to the air conditioner is detected by the secondary current detector 46, and the product of the output voltage VL and the current DC / DC is detected.
The output power of the converter can be determined. The output voltage VL may not be detected and may be set in advance in the control circuit.

If the solar cell generated power is below the output power limit value of the DC / DC converter and the air conditioner power consumption is above the output power limit value of the DC / DC converter, first, the primary voltage detection unit 44 And the primary current detector 4
Each signal detected by 5 is input to the control circuit 35, and the solar cell 9 is within the range of ΔI in the V-I characteristic diagram of the solar cell shown in FIG. The control circuit 35 controls the driving unit 36 so as to use the electric power of, and drives the power element (for example, MOS FET) 37 so that I is always within the range of ΔI.

When the power generated by the solar cell and the power consumed by the air conditioner are equal to or higher than the output power limit value of the DC / DC converter, the output power limit of the DC / DC converter causes
500 W of solar battery power is supplied to the room air conditioner, and the insufficient 500 W is supplied from the commercial power supply 1.

Further, when the solar cell generated power is above the output power limit value of the DC / DC converter and the air conditioner power consumption is below the output power limit value of the DC / DC converter (solar cell generated power: 1500 W, output power Limit value:
500 W, air conditioner power consumption: 300 W), or when the solar battery generated power is below the output power limit value of the DC / DC converter and the air conditioner power consumption is below the solar battery generated power (solar battery generated power: 400 W, output power (Limit value: 500 W, air conditioner power consumption: 300 W) is a power element (for example, a MOS FET) via the drive unit 36.
Control the on-time of 37 to reduce the power consumption of the air conditioner 300
Supply only W. At this time, when the output voltage VL rises and reaches a voltage at which the inverter of the air conditioner is destroyed, overvoltage protection is performed, the output voltage VL is detected, and the power is supplied via the drive unit 36 so that the voltage does not rise. The on time of the element (for example, MOS FET) 37 may be controlled.

The power that can be generated by the solar cell is 1500 W
And the capacity of the inverter 9 is 1000 W, and DC / D
When the limit value of the C converter 12 is determined to be 500 W, the power generation of the solar cell is wasted depending on the operating state of the room air conditioner (at 1500 W, the power that can be returned is 1000 W).
Therefore, if the room air conditioner is automatically operated at this time, 500 W will always be effectively utilized.

[0029]

According to the present invention, the DC / DC converter provided in the room air conditioner can always obtain the solar cell output according to the amount of solar radiation, and the comfort can be improved by automatically operating the air conditioner. Since the generated electric power of the solar cell can be fully utilized, the utilization rate of the solar cell can be significantly improved over the conventional one. Therefore,
It is possible to speed up the recovery of the initial cost of the solar cell or the like. Further, by limiting the output of the DC / DC converter, the capacity of the device can be reduced and general-purpose components can be used, so that the system cost can be significantly reduced. Further, when surplus power is generated in the amount of power generated by the solar cell, it can be returned to the commercial power system via an inverter, or household appliances that use the commercial power can be operated, which is even more economically advantageous. It can be a system.

[Brief description of drawings]

FIG. 1 is a block diagram of a room air conditioner system including a solar cell according to the present invention.

FIG. 2 is a block diagram showing a specific example of a DC / DC converter.

FIG. 3 is a characteristic diagram showing a specific example of optimum power control of a DC / DC converter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Commercial power supply, 9 ... Solar cell, 10 ... Inverter, 12 ... DC / DC converter, 16 ... Room air conditioner outdoor unit, 20 ... Room air conditioner indoor unit, 24 ... Rectifier circuit.

Claims (3)

[Claims] 1. A room air conditioner comprising an inverter circuit to which electric power obtained by converting alternating current from a commercial power source into direct current by a rectifier circuit and direct current power from a solar cell are supplied, and a compressor controlled by the inverter circuit. In the above, a DC / DC converter for controlling electric power generated by the solar cell according to a load state of the room air conditioner is provided in a pair with the room air conditioner, and an inverter is provided in a system of the commercial power supply. Solar air conditioner. 2. The inverter and the DC / DC converter connected to the system of the commercial power supply have operation control means, and the maximum output for obtaining maximum generated power from the solar cell by the operation means. The solar air conditioner according to claim 1, wherein the operating point voltage can be set. 3. The solar air conditioner according to claim 1, wherein the solar air conditioner is set to have a smaller capacity in the order of the power that can be generated by the solar cell, the capacity of the inverter, and the limit of the DC / DC converter.