JPH109640A - Solar air conditioner system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To significantly improve the utilization factor of a solar battery by providing a DC/DC converter between the solar battery and a room air conditioner and controlling the generated power of the solar battery to be optimum according to a load in a solar air conditioner system using a commercial power source and the the solar battery together. SOLUTION: The outdoor machines 9 to 12 of room air conditioners of respective homes are driven through rectifying circuits 17 to 20 and d.c. inverters from a commercial power source 1. The generated power of a solar battery 2 controls respective D/C DC converters 5 to 8 based on the quantity of solar radiation detected by a solar radiation quantity detecting part 4 and the operating conditions of the respective room air conditioners in a distribution control part 3 and the outputs are supplied to the inverters. At this time, the respective DC/DC converters 5 to 8 have an output power limiting value (50000 at maximum) so that the generated power within the limiting value of the solar battery 2 is supplied to the outdoor machines 9 to 12 of the respective room air conditioners. Thus, the respective capacities of the DC/DC converters 5 to 8 are decreased to make main parts compact.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a system including a plurality of room air conditioners using an inverter, and more particularly to a solar air conditioner system using both a commercial power supply and a solar cell.

[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. However, since their capacity changes due to the illuminance of sunlight and because they are current-type batteries, the power generated in overload conditions is limited. There is a problem that it is lowered, and its use is one of the major issues.

However, solar cells have been actively studied for application as an auxiliary power source for room air conditioners and the like, which consume a large amount of power, due to an increasing demand for electric power and the like. Recently, solar air conditioners have been commercialized. Is being done. These specifications are, for example, a solar battery with a maximum output of 500 W and a solar air conditioner for home use that connects one air conditioner. Since the solar battery outputs 500 W, when the power consumption of the air conditioner exceeds the solar battery output, the solar battery and the commercial AC power supply are operated in combination. 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.

[0004]

However, such a solar air conditioner is a home solar air conditioner that connects a solar cell having a maximum output of 500 W and one air conditioner, and unless a user operates the air conditioner. ,
The configuration is such that solar power is not used.
Therefore, there is a problem that the utilization rate of the photovoltaic power is low, and it takes a lot of years to recover the initial cost.

[0005]

SUMMARY OF THE INVENTION The present invention provides a solar battery in each inverter circuit of a plurality of room air conditioners to which DC power is supplied from a commercial power supply in order to increase the utilization rate of photovoltaic power. Between the solar cell and these room air conditioners, there is a DC / DC converter for controlling the supply of the generated electric power at the optimum operating point and the limited output control according to the amount of solar radiation of the solar cell. In addition, depending on the operating condition of the room air conditioner and the power generated by the solar cell,
A distribution control circuit for performing operation or stop control is provided.

Here, the DC / DC converter has a function of setting a limit value for the output supplied to the room air conditioner, and when the power generated by the solar cell is equal to or more than the limit value, the load of the room air conditioner is reduced. If the limit value or more, the generated power of the solar cell equivalent to the limit value is supplied to the room air conditioner, the generated power of the solar cell is less than the limit value, the room air conditioner load is When the generated power of the solar cell is equal to or more 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 is equal to or greater than the air conditioner load, the generated power of the solar cell equivalent to the load of the room air conditioner is supplied to the room air conditioner.

The distribution control circuit supplies the power generated by the solar cell via the DC / DC converter to a plurality of room air conditioners. The power generated by the solar cell is supplied, and if there is still surplus power, or if the room air conditioner is not operated by the user, the room air conditioner is automatically operated by the distribution control circuit.

Furthermore, when the room air conditioner is not operated by the user and the operation of the room air conditioner is automatically performed by the distribution control circuit, the operation is performed by switching the room air conditioner at predetermined intervals. .

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In the following embodiments, a description will be given of a system in which a plurality of homes such as apartments and condominiums are gathered as collective housing, and a system for collectively operating room air conditioners in each home is targeted. However, it is needless to say that the present invention is generally applied to a system for operating a plurality of room air conditioners collectively.

FIG. 1 is a block diagram showing an embodiment of a room air conditioner system equipped with a solar cell according to the present invention, wherein 1 is a commercial power supply, 2 is a solar cell, 3 is a distribution control unit,
Is a solar radiation detector, 5 to 8 are DC / DCs with optimal active power control.
DC converters, 9 to 12 are outdoor units of each room air conditioner, 13 to 16 are indoor units of these room air conditioners,
Reference numerals 17 to 20 denote rectification circuits of these room air conditioners.

In FIG. 1, in each of the outdoor units 9 to 12 of the room air conditioner in each home, electric power from the commercial power supply 1 is converted into DC by rectifier circuits 17 to 20 and supplied to an inverter (not shown). Drive.

The power generated by the solar cell 2 is controlled by the distribution control unit 3 to control each of the DC / DC converters 5 to 8 according to the amount of solar radiation detected by the solar radiation amount detection unit 4 and the operating condition of each room air conditioner. Then, the generated power is supplied from the solar cell 2 according to the load of the room air conditioner. And DC / D
The output of the C converter is supplied to an inverter (not shown) and drives a compressor motor (not shown).

Here, the DC / DC converters 5 to 8 are provided with output power limit values, and supply the power generated by the solar cells 2 to the room air conditioner outdoor units 9 to 12 within the limit values. As a result, the power generated by the solar cell 2 is sufficiently large, and the power consumption of the room air conditioner is all reduced by the solar cell 2.
In this case, only a certain amount of generated power (for example, 500 W) is supplied to each room air conditioner. The purpose of setting the output power limit value is DC / D
The capacity of each of the C converters 5 to 8 can be reduced, miniaturization of main components such as switching transformers, choke coils and power elements can be achieved, and general-purpose products can be used.
This is because the cost can be reduced.

First, the basic operation of the system in each of a solar cell, a DC / DC converter, and one 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 can be performed.

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

(For example, solar cell power: 1500
W, output power limit value: 500 W, room air conditioner power consumption 1000 W) The solar cell power generation is equal to or higher than the output power limit value of the DC / DC converter, and the room air conditioner power consumption is equal to or lower than the output power limit value of the DC / DC converter. Case.

(For example, solar cell power generation: 1500
(W, output power limit value: 500 W, room air conditioner power consumption: 300 W), the DC / DC converter output power limit supplies 500 W of solar cell power to the room air conditioner, and the shortage of 500 W to commercial power Supply from

In the case of (1), the DC / DC converter is controlled to supply only 300 W of power consumption of the room air conditioner.

Next, when the amount of solar radiation is small, the following two types of control are possible.

When the power generated by the solar battery is equal to or less than the output power limit value of the DC / DC converter, and the power consumption of the room air conditioner is equal to or more than the output power limit value of the DC / DC converter.

(For example, solar cell power generation: 400 W,
Output power limit value: 500W, room air conditioner power consumption:
1000W) The case where the solar cell generated power is equal to or less than the output power limit value of the DC / DC converter and the room air conditioner consumed power is equal to or less than the solar cell generated power.

(For example, solar cell power generation: 400 W,
Output power limit value: 500W, room air conditioner power consumption:
In the case of (300 W), the maximum active power of 400 W of the solar cell is supplied to the room air conditioner by the optimal active power control of the DC / DC converter.

In the case of (1), the DC / DC converter is controlled to supply only 300 W of power consumption of the room air conditioner.

Next, the operation of the DC / DC converter will be described with reference to FIG. The figure shows a DC / DC converter 5
8 shows an example of one of the devices, 39 is a voltage detection unit, 40 is a primary current detection unit, and 41 is a secondary current detection unit.

This DC / DC converter converts the power obtained from the voltage-current relationship of the solar cell 9 constantly fluctuating depending on the load and the amount of solar radiation to an air conditioner load such as an output power limit value and an optimum active power control. This is a device that changes the power in response to the change and increases the output voltage VL to the inverter input voltage of the air conditioner.

The output power limit value of the DC / DC converter is obtained by detecting the current supplied to the air conditioner by the secondary current detection unit 41 and obtaining the current DC / DC value by multiplying the output voltage VL.
The output power of the converter can be determined. Note that the output voltage VL may not be detected and may be set in advance in the control circuit.

When the power generated by the solar cell is equal to or less than the output power limit value of the DC / DC converter and the power consumption of the room air conditioner is equal to or more than the output power limit value of the DC / DC converter, as in the above example, First, the respective signals detected by the primary voltage detector 39 and the primary current detector 40 are input to the control circuit 30, and based on the information, the optimum point of the solar cell output is shown in FIG. As the power of the solar cell 2 is used within the range of ΔI in the VI characteristic diagram of the solar cell,
The control circuit 30 controls the drive unit 31 to drive the power element (for example, a MOS FET) 32 such that I is always within the range of ΔI.

When the power generated by the solar cell and the power consumed by the room air conditioner are equal to or greater than the output power limit value of the DC / DC converter as in the above example, the output power of the DC / DC converter is limited. 500
W of solar cell power is supplied, and the shortage of 500 W is supplied from the commercial power supply 1.

Further, as in the above example, when the power generated by the solar cell is equal to or higher than the output power limit value of the DC / DC converter and the air conditioner power consumption is equal to or lower than the output power limit value of the DC / DC converter, When the power generated by the solar cell is equal to or less than the output power limit value of the DC / DC converter and the power consumption of the air conditioner is equal to or less than the power generated by the solar cell, the signal detected by the secondary voltage detecting unit 42 The power is supplied to the control circuit 30, and the ON time of the power element (for example, a MOS FET) 32 is controlled via the drive unit 31 to supply only 300 W of power consumption of the air conditioner.

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 or detection of the output voltage VL is performed via the drive unit 36 so that the voltage does not rise. And a power element (for example, MO
The ON time of the SFET 32 may be controlled.

Next, the distribution control unit 3 will be described. In this case, it is assumed that there are a plurality of room air conditioners and the operation of them is appropriately controlled.

First, the case where the user does not operate the room air conditioner at all will be described.

In this case, the air conditioner is automatically operated with the surplus power of the photovoltaic power generation, and is kept at an arbitrary air conditioning level.
An object of the present invention is to reduce a start-up load or the like when a user starts operating a room air conditioner. The distribution control unit 3 randomly determines, for example, a priority number for causing the room air conditioner to automatically operate, and transmits a drive signal to the room air conditioner indoor unit and the DC / DC converter with the smaller number.

Next, from the current power generated by the solar cell 2,
The surplus power of the solar cell 2 excluding the power consumption of the room air conditioner that is automatically operated is calculated. If there is surplus power, the second room air conditioner indoor unit determined next and the DC / DC A drive signal is sent to the converter to perform automatic operation. Similarly, the third, fourth,... Room air conditioners are automatically operated.

In this case, the room air conditioner automatically operated by the distribution control unit 3 does not mean that the user wants to operate the room air conditioner spontaneously. Since it is not possible to pay for a room, it is driven only by the power generated by the solar cell 2, and the power consumption of the room air conditioner is DC / DC.
It is set so as to be equal to or less than the output power limit value of the converter.

When the power generated by the solar cell 2 decreases during the automatic operation, the distribution control unit 3 stops the operation from the previously determined priority number in descending order.

In the case where the total power consumption of the automatically operated room air conditioner and the generated power of the solar cell 2 are balanced even though there is a room air conditioner that is not automatically operated, it is determined first. By changing the priority number every certain time period, control is performed so that all room air conditioners can perform automatic operation equally. this is,
Even when the amount of solar radiation decreases or increases and the number of room air conditioners that can be automatically operated changes, the distribution control unit 3 switches the room air conditioner that performs automatic operation by changing the priority number, and This is to make the distribution of the power generated by the battery 2 uniform.

When a plurality of room air conditioners are operating automatically and a user starts operation of the room air conditioner at a certain moment, power is preferentially supplied to the room air conditioner which is operating the user. . Then, when the generated power of the solar cell 2 is larger than the power consumption of the room air conditioner performing the user operation, the distribution control unit 3 performs the automatic operation of another room air conditioner covered by the surplus power of the solar cell 2. Do. The same applies to a case where a plurality of room air conditioners are operated by the user.

Further, even when the power generated by the solar cell 2 is less than the total power consumption of a plurality of room air conditioners performing user operation, the power generated by the solar cell 2 supplied per unit is If the input lower limit value is equal to or more than the input lower limit value set by the DC / DC converter, the power generated by the solar cell 2 is evenly distributed so that the DC / DC converter of the room air conditioner that is being operated by another user can be operated. Distribute.

When the amount of solar radiation decreases or the number of room air conditioners operated by the user increases, the power generated by the solar cell 2 supplied per DC / DC converter falls below the set input lower limit value. May be less. In this case, the distribution control unit 3 stops one DC / DC converter of the room air conditioner performing the user operation.

At this time, among the room air conditioners that are being operated by the user, some of the room air conditioners are supplied with the power generated by the solar cell 2 and others are not supplied, resulting in unevenness. In such a case, the distribution control unit 3 controls the DC of the room air conditioner performing the user operation.
By switching the operation of the / DC converter every certain time, the room air conditioner performing the user operation can be
Control is performed so that the power generated by the solar cell 2 is evenly supplied.

Although the embodiment of the present invention has been described above, this is merely an example.
Although the number of room air conditioners is four in the drawing, it is needless to say that the number of room air conditioners is not limited to four.

[0044]

As described above, according to the present invention,
Distribution control unit and DC / D provided in each room air conditioner
With the C converter, the output of the solar cell according to the amount of solar radiation is always obtained, and by automatically operating the air conditioner, the power generated by the solar cell can be fully utilized. Can be greatly improved. Therefore, the recovery of the initial cost of the solar cell or the like can be accelerated.

Further, by providing a limit value to the output of the DC / DC converter, the capacity of the device can be reduced, and general-purpose components can be used. Therefore, the cost of the system, mainly the distribution control unit and the DC / DC converter Cost can be significantly reduced.

[Brief description of the drawings]

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

FIG. 2 is a configuration diagram illustrating a specific example of a DC / DC converter.

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

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Commercial power supply 2 Solar cell 3 Distribution control part 4 Solar radiation detection part 5, 6, 7, 8 DC / DC converter with optimal active power control 9, 10, 11, 12 Room air conditioner outdoor unit 13, 14, 15, 16 Room Air conditioner indoor unit 17, 18, 19, 20 Rectifier circuit 30 Control circuit 31 Drive unit 32 Switching element (FET) 33 Transformer 34, 35, 38 Diode 36 Choke coil 37 Smoothing capacitor 39 Primary voltage detection unit 40 Primary current detection Unit 41 Secondary current detection unit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor: Tetsunobu Okamura 800, Tomita, Ohira-cho, Ohira-machi, Shimotsuga-gun, Tochigi Prefecture Inside the Cooling and Refrigerating Business Dept., Hitachi, Ltd. No. Chugoku Electric Power Co., Inc. (72) Inventor Shigemi Inayama 4-33 Komachi, Naka-ku, Hiroshima-shi, Hiroshima Chugoku Electric Power Co., Inc.

Claims (3)

[Claims] 1. A plurality of room air conditioners having an inverter circuit to which power obtained by converting AC from commercial power into DC by a rectifier circuit and DC power from a solar cell are provided. A DC / DC converter with a maximum of 500 W is provided as a pair with the room air conditioner, and the DC / DC converter has a function of controlling the power generated by the solar cell to be optimal according to the load or the amount of solar radiation. Providing a distribution control circuit for distributing the power generated by the solar cell to each of the plurality of room air conditioners; and distributing the power when the room air conditioner is not operating while the power generated by the solar cell can be supplied. The operation of the room air conditioner is automatically performed by the control circuit, and when the operation of the room air conditioner is automatically performed, Solar air-conditioning system and performing the operation by switching the room air conditioner. 2. The DC / DC converter according to claim 1, wherein the power generated by the solar cell is equal to or more than a maximum value of 500 W and the load of the room air conditioner is equal to or more than a maximum value of 500 W. When the generated power of the solar cell of maximum 500 W is supplied to the room air conditioner, and the generated power of the solar cell is equal to or less than the maximum value of 500 W and the load of the room air conditioner is equal to or more than the maximum value of 500 W, When the generated power of the solar cell is maximized to supply power to the room air conditioner, the generated power of the solar cell is not more than a maximum value of 500 W and the load of the room air conditioner is not more than a maximum value of 500 W. Is a solar air-conditioning system for supplying the generated power of the solar cell equivalent to the load of the room air-conditioner to the room air-conditioner. 3. The user operation is started according to claim 1, wherein the operation of the room air conditioner is automatically performed by the distribution control circuit using the power generated by the solar cell. In this case, the solar air conditioner system is characterized in that the power generated from the solar cell is preferentially supplied to the room air conditioner that has been operated by the user.