JPH06272991A - Solar air conditioner - Google Patents

Abstract

PURPOSE:To alleviate a power source change of a commercial power source system due to a variation in a solar radiation by so controlling a load current of an electric load apparatus as to always hold an output voltage of a solar energy electric converter at an optimum operating voltage. CONSTITUTION:A reference voltage generator 7 generates an optimum operating voltage of a solar cell, sends it to a potential difference converter 8, obtains a difference from an outlet side voltage of a double voltage rectifier 4, and sends its difference signal to an ON/OFF deciding unit 9. The unit 9 sends, if the signal is positive (the reference voltage is high), a contact signal of an ON state to an inverter load controller 11 through a load current limiter 10, and lowers an inverter load. The limiter 10 monitors the load current, maintains the OFF state in the case of a lowest load current, and eliminates transmission of a control signal to the controller 11. Accordingly, an air conditioner is not stopped. That is, a variation in a commercial system power source is suppressed, and commercial AC power is deleted, thereby obtaining an energy conservation effect.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar air conditioner, and more particularly, to ensuring the same level of comfort as a normal air conditioner that does not use a solar cell, and to prevent a drastic change in the load on the commercial power source when the solar radiation fluctuates. The present invention relates to control means for suppressing.

[0002]

2. Description of the Related Art All conventional solar air conditioners employ a system in which a solar cell and a commercial power source are used together to supply electric power required for an inverter load. In this type of system, the solar cell output is given priority to be supplied to the inverter load, and the shortage of power is supplied from the commercial power source. In addition,
Due to legal regulations, the system is configured so that the solar cells cannot operate alone.

FIG. 7 is a diagram schematically showing a temporal change in a room temperature and a power system when a solar cell is directly connected to an inverter load side and a solar air conditioner is operated without any control. For example, when the air conditioner is started at 8:00 am, the inverter load power sharply increases and the impedance on the load side decreases, so that the inverter load voltage decreases. That is, the output voltage of the solar cell drops and temporarily falls below the optimum operating voltage.

FIG. 8 is a diagram showing the basic characteristics of a solar cell. As is clear from this figure, when the inverter load voltage drops from the optimum operating voltage, the output loss gradually increases. When the solar radiation increases when the room temperature is constant and the inverter load decreases, the impedance on the load side as viewed from the solar cell increases, so the inverter load side voltage, that is, the solar cell voltage rises and exceeds the optimum operating voltage. When the inverter load voltage exceeds the optimum operating voltage, the characteristics of the solar cell cause a sudden loss in the output of the solar cell, and the loss becomes larger than when the output voltage of the solar cell decreases.

As described above, in the solar air conditioner, how efficiently the solar cell output is supplied to the load, in other words,
The problem is how to match the impedance between the solar cell and the load.

[0006] Examples of this type of prior art include "Operating characteristics of solar cell air conditioners" (June 1992, published by the photovoltaic power generation conference, 9th photovoltaic power system symposium proceedings, pp5-
There are solar air conditioners listed in 23, ~ 5-30). In this solar air conditioner, the output of the solar cell is not directly connected to the outlet side of the rectifier circuit of the commercial power supply, but is connected via a DC / DC converter as an interface.

This system is provided with a solar cell maximum output point tracking control circuit. That is, a method is adopted in which the output voltage from the solar cell is controlled to the optimum operating voltage by changing the duty ratio of high frequency switching using a DC / DC converter.

FIG. 9 shows the operating characteristics of this type of prior art. Since the commercial AC power is supplied to compensate for the inverter load power that cannot be covered by the solar cell when the solar radiation decreases, the fluctuation becomes large. Especially, in a situation where cloud flow is fast and sunshine and shade are frequently repeated, this fluctuation frequently occurs in the entire region.

[0009]

The above-mentioned prior art has the following problems. (1) When the solar air conditioner with the above system configuration becomes widespread, power fluctuation of the commercial power system due to fluctuation of solar radiation becomes a problem. (2) In the conventional solar air conditioner control system,
Although it is possible to obtain the same comfort as a conventional air conditioner that does not use a solar cell, it requires a DC / DC converter and a maximum output point tracking control device (optimum operating voltage tracking control device), which leads to an increase in cost and a microcomputer chip. Since it is used, control becomes complicated and trouble factors become large. (3) The purpose of a solar air conditioner using a solar cell is to save energy, but no measures have been taken to further reduce commercial AC power without impairing the comfort of conventional air conditioners.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention adjusts DC power generated by rectifying commercial AC power by a rectifier and DC power generated by a solar energy electric converter by an inverter circuit to generate electricity. In a solar air conditioner that supplies load equipment, a reference voltage generator that generates the optimum operating voltage of the solar energy electric converter is compared with the output voltage of the reference voltage generator and the outlet side voltage of the rectifier to output a voltage difference signal. A potential difference converter, a load control determiner that determines the necessity of controlling the electric load device based on the potential difference signal, and an electric load that always maintains the optimum operating voltage for the output voltage of the solar energy electric converter based on the result of the determination. Proposing a solar air conditioner comprising a load control circuit for controlling the load current of equipment and a load current limiter for limiting the minimum value of the load current A.

Further, in order to achieve the above object, the present invention adjusts the DC power obtained by rectifying the commercial AC power by the rectifier and the DC power generated by the solar energy electric converter by the inverter circuit and supplies the DC power to the electric load equipment. In the solar air conditioner, a reference voltage generator that generates an optimum operating voltage of the solar energy electric converter, and a potential difference converter that compares the output voltage of the reference voltage generator and the outlet side voltage of the rectifier and outputs a voltage difference signal. A proportional converter that converts the potential difference signal into a signal that controls the input voltage to the rectifier, and a voltage regulator that adjusts the commercial AC voltage based on the rectifier input voltage control signal to control the solar cell output voltage to the optimum operating voltage. We propose a solar air conditioner consisting of a limiter that limits the upper and lower limit voltage of the voltage regulator.

Further, in order to achieve the above object, the present invention adjusts the DC power generated by rectifying commercial AC power by a rectifier and the DC power generated by a solar energy electric converter by an inverter circuit to supply an electric load device. In the solar air conditioner, a reference voltage generator that generates the optimum operating voltage of the solar energy electric converter and a potential difference converter that compares the output voltage of the reference voltage generator with the outlet side voltage of the rectifier and outputs a voltage difference signal. , A load control determiner that determines whether to control the electric load device based on the potential difference signal, and a load current of the electric load device that always maintains the optimum operating voltage for the output voltage of the solar energy electric converter based on the result of the determination. Control circuit, a load current limiter that limits the minimum value of the load current, and a potential difference signal that controls the input voltage to the rectifier. Converter that converts the output voltage into a signal, a voltage regulator that adjusts the commercial AC voltage based on the rectifier input voltage control signal to control the solar cell output voltage to the optimum operating voltage, and a commercial AC that limits the upper and lower limit voltage of the voltage regulator. The present invention proposes a solar air conditioner including a limiter that switches to control by a load control circuit when the voltage reaches an upper limit and returns to control by a voltage regulator when solar radiation is restored.

A reference voltage generator for generating the optimum operating voltage of the solar energy electric converter and a potential difference converter for comparing the output voltage of the reference voltage generator and the outlet side voltage of the rectifier and outputting a voltage difference signal. In place of the combination with the load control determination device that determines the necessity of controlling the electric load device based on the potential difference signal, the sensor for measuring the amount of solar radiation and the necessity of controlling the electric load device based on the amount of solar radiation. It is also possible to use a combination with a load control judging device for judging.

[0014]

In the control of the solar air conditioner according to the present invention, (1) focusing on energy saving, the inverter load is directly adjusted by following the solar radiation, and the voltage on the solar cell side is controlled to the optimum operating voltage of the solar cell. Method (2) Focus on comfort, adjust the voltage on the commercial power supply side,
A method of controlling the voltage on the solar cell side to the optimum operating voltage of the solar cell (3) Focusing on both energy saving and comfort, (1)
There is a control method that combines the methods of (2) and (2). The operation of the components of these control methods will be described below.

(1) Solar air conditioner control system with an emphasis on energy saving In order to obtain the highest energy saving effect in a solar air conditioner, the load is adjusted in accordance with solar radiation, and only solar cells are used without using commercial AC power. It is to be. In this case, depending on the day, the solar radiation fluctuates greatly, and power generation sufficient to cover the minimum load of the air conditioner cannot be performed, and the air conditioner may stop. Therefore, in this method, a solar cell and a commercial power source are used together to execute the solar radiation following load control. That is, when the solar radiation decreases, the inverter load is adjusted, the solar cell voltage is controlled to the optimum operating voltage to maintain high efficiency operation, the commercial AC power is reduced as much as possible to suppress the power fluctuation, and the air conditioner stop is avoided. To do.

The solar radiation following load control circuit comprises a reference voltage generator, a potential difference converter, an ON-OFF judging device, a load current limiter, an inverter load control circuit and the like. The reference voltage generator creates a reference voltage equivalent to the optimum operating voltage of the installed solar cell. The potential difference converter turns on and off the difference between the air conditioner rectifier outlet side voltage (solar cell side voltage) and the reference voltage.
Output to the judgment device. The ON-OFF determiner determines whether to send a control signal to the inverter load control circuit, and when the output of the potential difference converter is positive (solar radiation is low and reference voltage is higher), the ON-OFF determiner is transmitted. The load current limiter monitors the load current and turns OFF if the minimum load current
Then, the control signal is not transmitted to the inverter load control circuit. Therefore, the air conditioner will not be stopped. The inverter load control circuit is a circuit that limits the load current. Normally, the inverter air conditioner is equipped as an overload control circuit, which operates with an ON-OFF control signal and reduces the load current with an ON signal. To do.

If a device that outputs an electric signal representing the amount of solar radiation is used instead of the combination of the reference voltage generator and the potential difference converter, the solar radiation follow-up load control that can be operated only by the solar cell output corresponding to the amount of solar radiation. Is also possible.

(2) Solar air conditioner control system with emphasis on comfort The best control system of a solar air conditioner that maintains the same level of comfort as an air conditioner that does not use solar cells This is a control method that covers the required load power. According to this control method, the same electric power as when used alone is input to the air conditioner. in this case,
The solar cell voltage performs optimum operating voltage control from the viewpoint of highly efficient operation.

The optimum operating voltage control circuit comprises a reference voltage generator, a potential difference converter, a proportional converter, a voltage regulator, a voltage upper and lower limiter, and the like. The reference voltage generator creates a reference voltage equivalent to the optimum operating voltage of the installed solar cell. The potential difference converter outputs the difference between the air conditioner rectifier outlet side voltage (solar cell side voltage) and the reference voltage to the proportional converter. A proportional converter is a voltage regulator that converts the voltage output from the potential difference converter into a control amount that makes the voltage of the DC system to which the solar cell is connected the optimal operating voltage, and controls the voltage on the commercial power supply side. Send to. When the solar cell voltage is higher than the reference voltage, the commercial power supply side voltage is lowered, and when it is low, it is raised in reverse.
The solar cell side voltage is controlled to the optimum operating voltage. The voltage regulator may be any device that can adjust the voltage with a control signal,
Here, for example, a thyristor whose voltage can be adjusted by a control signal from a proportional converter is adopted. The upper limiter of the voltage upper and lower limiters limits the control signal of the voltage regulator, and is determined by the withstand voltage of an element installed downstream of the voltage regulator. The lower limit limiter is determined by a voltage that can supply the minimum load power from the commercial power supply. That is, it is possible to prevent an abnormal stop without being able to cover the load power when the solar radiation suddenly changes.

(3) Control method focusing on both energy saving and comfort The control method focusing on energy saving of (1) above and (2)
This is a control method that also uses a control method that places emphasis on comfort. That is, when the solar radiation fluctuation is small and the solar cell output does not change significantly and the high solar radiation state continues, (2)
When the solar radiation fluctuation is extremely large and the solar cell output changes greatly, the control shifts to (1) the emphasis on energy saving. Therefore, when the solar radiation fluctuation is small, the solar cell is operated at the optimum operating voltage to ensure high efficiency. Comfort is ensured because there is no inverter load control. An energy saving effect can be obtained because the solar cell is operated with high efficiency. Voltage fluctuations in the commercial power system are reduced. On the other hand, when the solar radiation fluctuation is large, the solar cell is operated at the optimum operating voltage operation to ensure high efficiency. Even if the control for reducing the inverter load is executed, if the solar radiation decreases greatly, the temperature will decrease and the comfort can be maintained. Further, the energy saving effect can be obtained by the high efficiency operation of the solar cell and the load reduction. By reducing the load, voltage fluctuations in the commercial power system are reduced.

The control circuit is composed of the circuit elements shown in (1) and (2) above. In this control method, the determination of the control method transition is executed by the voltage upper limit limiter. That is, in the operating state of the voltage upper limiter where the solar cell voltage greatly decreases with the decrease in solar radiation and the voltage regulator cannot control the optimum operating voltage of the solar cell, the control moves to (1) control, and when solar radiation is recovered, Move on to control that emphasizes comfort in (2). Therefore, the voltage upper limit limiter shown here is determined from the limit value of the inrush power from the commercial power supply system in consideration of the withstand voltage of the element shown in (2) above.

[0022]

【Example】

<< Embodiment 1 >> FIG. 1 is a block diagram showing a system configuration of an embodiment of a solar air conditioner control device according to the present invention, which focuses on energy saving. In the power supply system of the solar air conditioner of this embodiment, from the commercial power supply 1 to the indoor unit 2 of the air conditioner, to the voltage doubler rectifier 4 of the outdoor unit 3 of the air conditioner, to the inverter load 5, and from the solar battery 6. Via the output side of the voltage doubler rectifier 4, the inverter load 5
There are two systems, a system for supplying to. A solar radiation following load control circuit is provided as a control system for adjusting the power supplied from these two power supply systems. The solar radiation following load control circuit includes a reference voltage generator 7, a potential difference converter 8, and an ON-O.
It includes an FF determiner 9, a load current limiter 10, and an inverter load control circuit 11.

A conventional solar air conditioner of a system in which a solar cell is simply added to an air conditioner which operates only with commercial AC power employs a load control system which is premised on constant power supply. Therefore, when the power supplied to the solar cell side fluctuates due to fluctuations in solar radiation, power fluctuations in the commercial power system occur in order to compensate for the insufficient power.

On the other hand, in this embodiment, a solar radiation following load control circuit for directly controlling the load by following the solar radiation is added to the load control system to lower the inverter load and turn on when the solar radiation decreases. It has a function to suppress the commercial AC power to reduce the fluctuation of the power supply of the commercial power system.

FIG. 2 is a schematic diagram showing the operating characteristics of the solar air conditioner of FIG. 1 using the solar radiation following load control circuit.
In a solar air conditioner in which a solar cell is simply connected to a commercially available air conditioner, under a constant load, when the solar radiation decreases, commercial AC power is supplied to supplement the insufficient power. Therefore, the fluctuation of the commercial power source increases in proportion to the solar radiation. When the solar radiation decreases, the impedance of the solar cell decreases, the voltage on the solar cell side decreases, and it falls below the optimum operating voltage, making it impossible to operate the solar cell with high efficiency.

Therefore, in the present embodiment, the reference voltage generator 7 generates the optimum operating voltage of the solar cell and sends it to the potential difference converter 8 to obtain the difference from the outlet side voltage of the voltage doubler rectifier 4, and the difference The signal is sent to the ON-OFF judging device 9. ON-
If the difference signal is positive (the reference voltage is high), the OFF determiner 9 sends a contact signal in the ON state to the inverter load control circuit 11 via the load current limiter 10 to lower the inverter load. The inverter load control circuit 11 is a circuit that limits the load current, and is usually equipped in an inverter air conditioner as an overload control circuit. The inverter load control circuit 11 operates with an ON-OFF control signal, and functions to reduce the load current with an ON signal. The load current limiter 10 monitors the load current, and if it is the minimum load current, maintains the OFF state and cancels the transmission of the control signal to the inverter load control circuit 11. Therefore, the air conditioner will not be stopped. That is, while controlling the solar cell voltage during sunshine to the optimum operating voltage to perform high-efficiency operation, reduce the inverter load during low sunlight, avoid commercial AC power input, and suppress fluctuations in the power supply of the commercial grid. Reduces commercial AC power and brings energy savings.

In the solar air conditioner control apparatus of FIG. 1, a solar radiation amount measuring sensor (not shown here) is provided in place of the reference voltage generator 7 and the potential difference converter 8, and its output is turned on and off. If the solar air conditioner is changed so as to be sent to the determiner 9, a solar air conditioner capable of operating control with the highest energy saving effect can be obtained in which the inverter load is covered only by the solar cell output based on the amount of solar radiation.

<Embodiment 2> The best control method for ensuring comfort in a solar air conditioner without using a solar cell is to control the load power required by the air conditioner with the solar cell and commercial power supply. . When this control method is adopted, the same level of comfort as when using an air conditioner alone that does not use a solar cell can be obtained. In this case, regarding the solar cell voltage, the optimum operating voltage tracking control is executed from the viewpoint of highly efficient operation.

FIG. 3 is a block diagram showing the system configuration of an embodiment of the solar air conditioner control device according to the present invention, which places emphasis on comfort. The power supply system of the solar air conditioner of the present embodiment passes from the commercial AC power system 1 through the air conditioner indoor unit 2, through the voltage regulator (thyristor) 12 and the voltage doubler rectifier 4 of the air conditioner outdoor unit 3, and to the inverter load 5. There are two systems, a system for supplying and a system for supplying to the inverter load 5 from the solar cell 6 as in the first embodiment.
As a control system that adjusts the power supplied from these two power supply systems, there is a solar cell optimum operating voltage tracking control circuit. The solar cell optimum operating voltage tracking control circuit includes a reference voltage generator 7, a potential difference converter 8, a proportional converter 13, and a voltage upper / lower limit limiter 14.

The optimum operating voltage tracking of the solar cell can be performed by adjusting at least one of the impedance on the commercial power source side, the impedance on the solar cell side, and the impedance on the inverter load side. In the prior art, the impedance is matched by changing the voltage on the solar cell side. This conventional method requires a DC / DC converter and a maximum output point tracking control device (optimum operating voltage tracking control device), which not only causes a large increase in cost, but also uses a microcomputer chip, so that control is not performed. It becomes complicated and causes of troubles increase. On the other hand, in Example 1 described above, the impedance was matched by changing the inverter load.

On the other hand, in this embodiment, the same effect as that of the prior art can be obtained, and further, the solar cell optimum operating voltage tracking control circuit is provided to control the impedance matching by changing the input voltage on the commercial power source side. The method is adopted. This solar cell optimal operating voltage tracking control circuit has a simple control system configuration and is low in cost. FIG. 4 is a schematic diagram showing operating characteristics of the solar air conditioner of FIG. 3 using the optimal operating voltage tracking control circuit. In a solar air conditioner in which a solar cell is simply connected to a commercially available air conditioner, under a constant load, commercial AC power is input to compensate for insufficient power when the solar radiation decreases. Therefore, the fluctuation of the commercial power source increases in proportion to the solar radiation. When the solar radiation drops,
Since the impedance of the solar cell becomes smaller, the voltage on the solar cell side drops, and it falls below the optimum operating voltage.
High-efficiency operation of solar cells becomes impossible.

In this embodiment, the reference voltage generator 7 generates the optimum operating voltage of the solar cell so that the potential difference converter 8 can maintain the comfort of the solar air conditioner without the solar cell. Then, the potential difference converter 8 calculates the difference from the outlet side voltage of the voltage doubler rectifier 4, sends the difference signal to the proportional converter 13, converts it to the control voltage of the voltage regulator 12 of the commercial power supply, and converts this control voltage. The commercial voltage is reduced by transmitting the voltage to the voltage regulator 12 via the voltage limiter 14 to control the solar cell side voltage (the outlet voltage of the voltage doubler rectifier 4) to the optimum operating voltage. Voltage limiter 1
The upper limit value of 4 is for limiting the control signal of the voltage regulator, and is determined by the withstand voltage of the element installed downstream of the voltage regulator. The lower limit value of the voltage upper and lower limiter 14 is determined by a voltage that can supply the minimum load power from the commercial power supply. That is, it is possible to prevent an abnormal stop without being able to cover the load power when the solar radiation suddenly changes.

By adopting this control method, it is possible to provide a highly reliable and inexpensive optimum operating voltage tracking control circuit which can operate the solar cell with high efficiency and maintain the same level of comfort as an air conditioner without using the solar cell.

<Embodiment 3> As for comfortable control by a solar air conditioner, the constant room temperature control shown in Embodiment 2 of FIG. 3 is the best, but power fluctuation of the commercial AC power system, which will be a problem in the future, is suppressed to save energy. It cannot be increased further.

Therefore, while maintaining the conventional comfort,
In order to achieve high energy saving while mitigating fluctuations in the commercial power source, a control method that combines the solar radiation following load control method of the first embodiment and the optimum operating voltage tracking control method of the second embodiment is conceivable.

The basic idea of this control method is as follows. A. In the case of long-span solar radiation changes, the temperature characteristics that change with solar radiation are used. That is, when the temperature drops due to low solar radiation, sensible comfort can be maintained even if the inverter load is lightened. However, the solar cell voltage is controlled at the optimum operating voltage even when the inverter load is lightened. B. For small changes in solar radiation The voltage on the commercial power supply side is changed to maintain the solar cell voltage at the optimum operating voltage, and the load power is the normal load power, that is, the inverter load power under the constant room temperature control.

FIG. 5 is a block diagram showing a system configuration of an embodiment of the solar air conditioner control apparatus according to the present invention, in which comfort and energy saving are put side by side. The power supply system of the solar air conditioner is from the commercial AC power system 1 through the air conditioner indoor unit 2 and through the commercial voltage regulator 12 and the voltage doubler rectifier 4 of the air conditioner outdoor unit 3 to the inverter load 5 and the solar power supply system. 2 with the system that is supplied from the battery 6 to the inverter load 5 via the outlet side of the voltage doubler rectifier 4
There is a lineage. The control system that adjusts the power supplied from these two power supply systems includes a reference voltage generator 7, a potential difference converter 8, a proportional converter 13, and a voltage upper and lower limiter 14.
ON / OFF determiner 9 and load current limiter 10
And an inverter load control circuit 11.

FIG. 6 is a schematic diagram showing the operating characteristics of the solar air conditioner of FIG. 5 in which the solar radiation following load control circuit and the optimum operating voltage tracking control circuit are used together. When the solar radiation fluctuation is small, the voltage fluctuation on the solar cell side is small, so the voltage control width in the optimum operating voltage control of the solar cell is also small, and the power supply fluctuation of the commercial power system is also small. In terms of temperature, there is little fluctuation in solar radiation, so there will be no significant decrease. In such a situation, in order to maintain comfort, the optimum operating voltage tracking control of the solar cell shown in the second embodiment is executed. That is, the reference voltage generator 7 generates the optimum operating voltage of the solar cell, sends it to the potential difference converter 8, finds the difference with the outlet side voltage of the voltage doubler rectifier 4, and sends the difference signal to the proportional converter 13. The voltage is converted into the control voltage of the voltage regulator 12 of the commercial power source, the control voltage is transmitted to the voltage regulator 12 via the voltage upper and lower limiter 14, the commercial voltage is lowered, and the solar cell 6 side voltage (double voltage rectifier 4 outlet Voltage) to the optimum operating voltage. The upper limit value of the voltage upper and lower limiter 14 becomes a judgment value of branch control between the solar radiation following load control method and the optimum operating voltage tracking control method. As the solar radiation decreases, the voltage of the solar cell 6 drops significantly, and when the voltage regulator 12 cannot perform the optimal operating voltage tracking control of the solar cell 6 and the voltage upper limiter 14 is in the operating state, the solar radiation follow-up load control is performed. , When the solar radiation is restored, the control returns to the optimum operating voltage tracking control. Therefore, the voltage upper limiter 14 shown here is determined from the viewpoint of limiting the inrush power from the commercial system in consideration of the withstand voltage of the element.

When the solar radiation fluctuation is large, the voltage fluctuation on the solar cell side is large, so the voltage control width in the optimum operating voltage control of the solar cell is large, and the power supply fluctuation of the commercial AC power system is also large. In terms of temperature, it greatly decreases due to large fluctuations in solar radiation. Therefore, in such a situation, comfort can be secured even if the inverter load is slightly reduced. In such a situation, the solar radiation following load control is executed. That is, in the operating state of the voltage upper limiter 14, the voltage difference signal from the proportional converter 13 is sent to the ON-OFF determiner 9, and it is determined whether or not to send the load control ON-OFF signal. ON if positive (high reference voltage)
The contact signal of the state is transmitted to the inverter load control circuit 11 via the load current limiter 10, and the control for lowering the inverter load 5 is executed. Here, the inverter load control circuit 11 is a circuit that limits the load current, and is installed in a normal inverter air conditioner as an overload control circuit. The inverter load control circuit 11 operates with an ON-OFF control signal and reduces the load current with an ON signal. The load current limiter 10 monitors the load current, and if it is the minimum load current, maintains the OFF state and cancels the transmission of the control signal to the inverter load control circuit 11. Therefore, the air conditioner will not be stopped.

When this control method is adopted, the solar cell voltage during sunshine is controlled to the optimum operating voltage to perform high-efficiency operation, while the inverter load is lowered when large fluctuations in solar radiation occur, and commercial AC power is avoided. In addition, the power supply fluctuation of the commercial power supply system is suppressed, the commercial AC power is reduced, and the energy saving effect is obtained while maintaining the comfort.

[0041]

【The invention's effect】

(1) Effects of solar radiation following load control system (a) New function In conventional solar air conditioners, regardless of changes in solar radiation,
Assuming that the required power of the air conditioner is constant and the shortage of solar cell output power was covered by commercial AC power, the commercial AC power was supplied in pulses when the solar radiation was low. Therefore, the power supply fluctuation of the commercial power supply system is large, and the commercial power supply system is adversely affected. In the present invention, a solar radiation follow-up load control system is provided that controls the inverter load power so that the voltage of the solar cell becomes the optimum operating voltage in response to the solar radiation situation and suppresses the commercial AC power that is input when the solar radiation decreases. . (B) Improvement of performance and efficiency As a result, the solar cell voltage can always be maintained at the optimum operating voltage without being affected by solar radiation fluctuations, and the solar cell can be operated with high efficiency. When the solar radiation is low, the inverter load power can be reduced, the commercial AC power input can be suppressed, and the power fluctuation of the commercial AC power system can be reduced. (C) Economical efficiency and simplification It is possible to reduce the inverter load power and suppress the commercial AC power input during low solar radiation, and reduce the amount of power input from the commercial AC power system. Since the inverter load power can be adjusted by a simple comparison circuit and the voltage of the solar cell can be set to the optimum operating voltage, the cost of the device can be reduced.

(2) Effects of the optimum operating voltage tracking control system (a) New function In the conventional solar air conditioner, the optimum operating voltage tracking control device is used to make the voltage of the solar battery the optimum operating voltage. Since the DC / DC converter connected to was controlled, not only the cost was increased, but also complicated control was executed by using a microcomputer chip, so that there were many trouble factors. On the other hand, in the present invention, the optimum operating voltage tracking control system that adjusts the voltage on the commercial power source side by using a simple comparison circuit to make the voltage of the solar cell the optimum operating voltage is provided. (B) Improved performance and efficiency The solar cell voltage can always be maintained at the optimum operating voltage without being affected by solar radiation fluctuations, and high-efficiency operation of the solar cell can be performed. (C) Economical efficiency and simplification Since the voltage of the commercial power supply side can be adjusted by a simple comparison circuit and the voltage of the solar cell can be maintained at the optimum operating voltage, the cost of the device can be reduced.

(3) Effects of a side-by-side control system including a solar radiation following load control system and an optimum operating voltage tracking control system (a) New function The purpose of a solar air conditioner using a solar cell is to maintain the comfort of a conventional air conditioner. , To improve the energy saving effect. However, the conventional method has not been able to further improve the energy saving effect while maintaining the comfort. On the other hand, in the present invention, the voltage on the commercial power source side is controlled by using a control system that controls the inverter load power so that the voltage of the solar cell becomes the optimum operating voltage according to the solar radiation condition, and a simple comparison circuit. When used together with a control system that adjusts the voltage of the solar cell to the optimum operating voltage, and if there is little fluctuation in solar radiation, use a control system that adjusts the voltage on the commercial power supply side to make the voltage of the solar cell the optimum operating voltage. When the fluctuation of solar radiation is large, a control system having a function of controlling the inverter load power so that the voltage of the solar cell becomes the optimum operating voltage according to the fluctuation of solar radiation is provided. (B) Improvement of performance and efficiency When the solar radiation drop is small, the inverter load adjustment is not performed, and only when the solar radiation drop is large, the load is reduced.
The inverter load can be reduced and comfort can be maintained only when the temperature drops due to insolation. The solar cell voltage can always be maintained at the optimum operating voltage without being affected by solar radiation fluctuations, and the solar cell can operate with high efficiency. When the solar radiation is low, the inverter load power is reduced, so that the input of commercial AC power can be suppressed and the fluctuation of the power supply of the commercial AC power system can be reduced. (C) Economical and simplification It is possible to reduce the inverter load power during low solar radiation, suppress the input of commercial AC power, and reduce the amount of power input from the commercial AC power system. The cost can be reduced by adjusting the voltage on the commercial power source side, adjusting the inverter load power, and setting the voltage of the solar cell to the optimum operating voltage with a simple comparison circuit.

(4) Effects of solar radiation amount tracking control system (a) New function The purpose of the solar air conditioner using a solar cell is to improve the energy saving effect without impairing the comfort of the conventional air conditioner. However, the conventional method cannot improve the energy saving effect while maintaining the comfort. The most effective way to save energy is to enable operation with a single solar cell power source. Therefore, in the present invention, a solar radiation amount follow-up control system that controls the inverter load power according to the solar radiation state, that is, the solar cell output is provided. (B) Improving performance and efficiency At the time of sunlight, the air conditioner can be operated only by the output of the solar cell, which maximizes the energy saving effect. (C) Economical efficiency and simplification The air conditioner can be operated without supplying commercial AC power to the load, resulting in a significant reduction in electricity charges.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a configuration of a control system of a solar air conditioner including a solar radiation following load control circuit according to the present invention.

FIG. 2 is a schematic diagram showing operating characteristics of a solar air conditioner including a solar radiation following load control circuit according to the present invention.

FIG. 3 is a block diagram showing an example of a configuration of a control system of a solar air conditioner including an optimum operating voltage tracking control circuit according to the present invention.

FIG. 4 is a schematic diagram showing operating characteristics of a solar air conditioner including an optimum operating voltage tracking control circuit according to the present invention.

FIG. 5 is a block diagram showing an example of the configuration of a control system of a solar air conditioner that uses both a solar radiation following load control circuit and an optimum operating voltage tracking control circuit according to the present invention.

FIG. 6 is a schematic diagram showing operating characteristics of a solar air conditioner that uses both a solar radiation following load control circuit and an optimum operating voltage tracking control circuit according to the present invention.

FIG. 7: A solar cell is directly connected to the inverter load side,
It is a schematic diagram which shows the room temperature and the state change of an electric power system at the time of driving without controlling anything.

FIG. 8 is a diagram showing basic characteristics of a solar cell.

FIG. 9 is a block diagram showing an example of a system configuration of a conventional solar air conditioner that supplies an output of a solar cell to an inverter load via a DC / DC converter.

[Explanation of symbols]

 1 Commercial power supply 2 Air conditioner indoor unit 3 Air conditioner outdoor unit 4 Double voltage rectifier 5 Inverter load 6 Solar cell 7 Reference voltage generator 8 Potential difference converter 9 ON-OFF judgment device 10 Load current limiter 11 Inverter load control circuit 12 Voltage regulator 13 Proportional converter 14 Voltage upper and lower limiter

Claims (4)

[Claims] 1. A solar air conditioner for adjusting DC power generated by rectifying commercial AC power by a rectifier and DC power generated by a solar energy electric converter and supplying the adjusted electric power to an electric load device. A reference voltage generator for generating the optimum operating voltage, a potential difference converter that outputs a voltage difference signal by comparing the output voltage of the reference voltage generator with the outlet side voltage of the rectifier, and the electric potential difference signal based on the electric potential difference signal. A load control determiner that determines whether or not control of the load device is necessary, and a load that controls the load current of the electric load device so that the output voltage of the solar energy electric converter always maintains the optimum operating voltage based on the result of the determination. A solar air conditioner comprising a control circuit and a load current limiter for limiting the minimum value of the load current. 2. A solar air conditioner for supplying electric load equipment by adjusting DC power generated by rectifying commercial AC power by a rectifier and DC power generated by a solar energy electric converter to supply an electric load device. A reference voltage generator for generating the optimum operating voltage, a potential difference converter that outputs a voltage difference signal by comparing the output voltage of the reference voltage generator and the outlet side voltage of the current regulator, and the potential difference signal A proportional converter that converts the input voltage to the rectifier into a signal that controls the voltage; a voltage regulator that adjusts the commercial AC voltage based on the rectifier input voltage control signal to control the solar cell output voltage to the optimum operating voltage; A solar air conditioner characterized by comprising a limiter for limiting the upper and lower limit voltage of the unit. 3. A solar air conditioner for supplying an electric load device by adjusting DC power generated by rectifying commercial AC power by a rectifier and DC power generated by a solar energy electric converter, the solar energy electric converter. A reference voltage generator for generating the optimum operating voltage, a potential difference converter that outputs a voltage difference signal by comparing the output voltage of the reference voltage generator with the outlet side voltage of the rectifier, and the electric potential difference signal based on the electric potential difference signal. A load control determiner that determines whether or not control of the load device is necessary, and a load that controls the load current of the electric load device so that the output voltage of the solar energy electric converter always maintains the optimum operating voltage based on the result of the determination. A control circuit, a load current limiter for limiting the minimum value of the load current, and a signal for controlling the input voltage to the rectifier by the potential difference signal. Converter that converts the commercial AC voltage to the optimum operating voltage by adjusting the commercial AC voltage based on the rectifier input voltage control signal, and limits the upper and lower limit voltage of the voltage regulator. A solar air conditioner comprising: a limiter for returning to control by the voltage regulator when the solar radiation is restored by switching to control by the load control circuit when the commercial AC voltage reaches an upper limit. 4. A solar air conditioner for supplying an electric load device by adjusting, with an inverter circuit, DC power obtained by rectifying commercial AC power with a rectifier and DC power generated by a solar energy electric converter, and a solar radiation measuring sensor. A load control determiner that determines whether or not to control the electric load device based on the amount of solar radiation, and an electric load so that the output voltage of the solar energy electric converter always maintains an optimum operating voltage based on the result of the determination. A solar air conditioner comprising a load control circuit for controlling a load current of a device and a load current limiter for limiting a minimum value of the load current.