JPH07190464A - Control method for solar cell driven air conditioner - Google Patents

Abstract

PURPOSE:To obtain output from solar cells to the maximum extent by always maintaining the inlet voltage from the solar cells at around the voltage at the point of highest efficiency. CONSTITUTION:A controller 9 of a converter 8 detects inlet voltage Di and inlet current of the converter 8 and calculates the output of the solar cells 7 (the product of inlet voltage Di and inlet current). When the inlet voltage Di from the solar cells 7 is higher than the voltage at the point of highest efficiency of the solar cells 7, the raised output voltage Do of the converter 8 is set higher than the voltage at a direct current part 2o. When the inlet voltage Di from the solar cells 7 is lower than the voltage at the point of highest efficiency of the solar cells 7, the raised output voltage Do of the converter 8 is gradually lowered corresponding to the drops in the inlet voltage Di from the solar cells 7 so that the inlet voltage Di from the solar cells 7 is always kept at around the voltage at the point of highest efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell driven air conditioner for driving a compressor by using a direct current power source such as a solar cell in addition to an ordinary commercial alternating current power source. Power is supplied from the commercial power supply side, the solar energy cannot be sold back to the commercial power supply side even if the output on the solar cell side has a margin compared to the air conditioning load. It is related to the control method used to the maximum extent.

[0002]

2. Description of the Related Art Conventionally, a solar cell driven air conditioner has a solar cell output (voltage, voltage, etc.) during operation because the solar energy output fluctuates greatly due to the weather and the characteristics of the solar cell fluctuate greatly with load. The electric current) fluctuates greatly, and it cannot be said that the solar cell is not always operating at an efficient output point in terms of solar utilization.

FIG. 4 is a block diagram of a conventional solar cell driven air conditioner. 1 is single phase 100V or 200V
2 is a rectifier that rectifies the commercial AC power supply 1, and is usually a capacitor (not shown). Reference numeral 3 is an inverter for converting the DC voltage at the outlet 2o of the rectifier 2 into an arbitrary AC frequency, and 4 is a compressor driven by the number of revolutions of the frequency converted by the inverter 3, and usually includes a motor 4'and a refrigerant. (Not shown) is enclosed, and the refrigerant is compressed by energizing the motor 4 ′ during the cooling / heating operation. Especially during heating, since the compressor 4 is in the atmosphere of low outdoor temperature outside the room, the refrigerant may be stored in the compressor 4 and jump out of the compressor 4 together with the oil when the operation is started.
An indoor unit 5 sends cool air to the room during cooling and sends hot air during heating to control the temperature of the indoor air. 6 is a commercial AC power supply 1
It plays the role of carrying heat with an outdoor fan driven by.
A solar cell 7 generates direct current power by solar radiation.
Reference numeral 8 denotes a DC / DC conversion converter for boosting the inlet voltage Di from the solar cell 7 to the outlet voltage Do.
By connecting the output section 8o boosted by and the DC section 2o at the outlet of the rectifier 2, the output from the solar cell 7 as well as the commercial AC power supply 1 is used to supply electric power to the compressor 4, It constitutes a battery-powered air conditioner.

FIG. 5 shows the characteristics of the solar cell 7, particularly the power-voltage characteristics and the current-voltage characteristics with the amount of solar radiation as a parameter. It shows that the characteristics change greatly depending on the amount of solar radiation and the load. The characteristics of the solar cell change depending on the amount of solar radiation, the ambient temperature, etc., but the maximum efficiency (output) point (for example, A1, A2, A3 points in FIG. 5) at any ambient temperature and the amount of solar radiation Exists.

In the solar cell driven air conditioner configured as described above, when there is solar radiation, the compressor 4 is driven by the output from the solar cell 7. When the output from the solar cell 7 is less than the air conditioning load (compressor load), or when there is almost no output from the solar cell 7 at night or in the rain, the commercial AC power supply 1 supplies power to the compressor 4 To drive. The output of the solar cell 7 is not always at the point of maximum efficiency as shown in FIG. 5 (A1, A2, A3, etc. as described above), and is not always stable at this point. The output point of the solar cell 7 fluctuates greatly depending on the balance between the amount of solar radiation and the air conditioning load, and there are operating conditions where efficiency (power) is poor.
It could not be said that the usage of the solar cell 7 was efficient.

When the load of the compressor 4 is smaller than the output from the solar cell 7, there is no cooling / heating load, and when the compressor is stopped during operation, the output of the solar cell 7 is naturally Despite that, there is no way to return the power to the commercial power source side like the reverse flow method, and it is necessary to operate the vehicle with a deviation from the maximum efficiency point of the solar cell 7, or play without using the energy of the solar cell. There was a problem of getting out.

[0007]

SUMMARY OF THE INVENTION In view of the above problems, the present invention is to control a converter that increases the output voltage from the solar cell so as to always obtain the maximum output from the solar cell. That is, when the compressor load is smaller than the solar cell output, the output of the solar cell preferentially covers the compressor load. Conversely, when the compressor load is larger than the solar cell output, the solar cell is It is about controlling to operate at the highest efficiency point.

Further, when there is no cooling / heating load or when the compressor is stopped during the heating / cooling operation, the refrigerant accumulates in the compressor even when the solar cell is idle, and a so-called sleep operation is performed. Then, there is a risk that the life of the compressor will be impaired. Conventionally, the compressor is operated in open phase from a commercial power source via an inverter to substitute for the heater,
The compressor was heated to drive out the refrigerant.

If the output from the solar cell is larger than the load of the compressor and there is a margin, the air conditioning setting in the room is set stronger than it is currently (set lower during cooling and higher during heating). Therefore, the solar cell is effectively used.

Furthermore, even if the output from the solar cell has a margin and the air conditioning setting in the room is increased, it is useless to increase the discomfort in terms of comfort, so that the range of comfort in the room is not impaired. Must be done in-house.

[0011]

In order to solve the above problems (achieve the object), the present invention provides: 1) a rectifier for rectifying a commercial AC power supply, and an inverter for converting the voltage of the DC portion at the outlet of the rectifier into an AC frequency. , In the air conditioner consisting of a compressor etc. driven by this inverter,
Providing a converter that boosts the inlet voltage from the solar cell,
A solar cell driven air conditioner is configured by connecting the output voltage boosted by this converter and the DC part of the rectifier. The converter is provided with a control unit, and the inlet voltage of the converter,
The inlet current is detected, and therefore the solar cell output (the product of the inlet voltage and the inlet current) is calculated. If the inlet voltage of the converter becomes higher than the maximum efficiency point voltage of the solar cell, the boosted output voltage of the converter is set higher than the voltage of the DC part to maximize the output from the solar cell. In addition, if the inlet voltage from the solar cell becomes lower than the maximum efficiency point voltage of the solar cell, set the voltage of the boosted output of the converter by gradually lowering it according to the lowering of the inlet voltage from the solar cell. The inlet voltage from the solar cell is controlled to be near the maximum efficiency point voltage.

2) A rectifier for rectifying a commercial AC power source, an inverter for converting the voltage of the DC portion at the outlet of the rectifier to an AC frequency, an air conditioner including a compressor driven by this inverter, and an inlet voltage from a solar cell. Is provided, and the output voltage boosted by this converter is connected to the DC portion of the rectifier to form a solar cell driven air conditioner. And, especially when the compressor is stopped during the heating operation, there is a control method for energizing the compressor with the output of the solar cell.

3) An outdoor unit comprising an indoor unit for controlling the indoor air temperature, a rectifier for rectifying a commercial AC power source, an inverter for converting the voltage of the DC portion at the outlet of the rectifier, a compressor driven by the inverter, an outdoor fan, etc. An air conditioner is configured by connecting the air conditioner and the indoor unit. A solar cell is provided, a converter that boosts the inlet voltage from the solar cell, and a solar cell drive air conditioner is configured by connecting the boosted output voltage of the converter and the DC portion. The converter is provided with a control unit, which is configured to detect the inlet voltage and the inlet current of the converter, and thus calculates the solar cell output. When the inlet voltage from the solar cell is higher than the maximum efficiency point voltage of the solar cell, cooling and heating are further strengthened compared to the current indoor air temperature set value. That is, it has a control method of decreasing the indoor air temperature during cooling and increasing it during heating.

4) Further, as a method of providing indoor comfort index detecting means in this indoor unit to enhance cooling and heating, when the indoor comfort index becomes uncomfortable than the current value, it is within the comfortable permissible range. Therefore, the control method is such that the room air temperature is lowered during cooling and raised during heating.

[0015]

With the above means, the converter inlet voltage and inlet current are detected by the converter control unit. In addition, the output from the solar cell (product of inlet voltage and inlet current) is also calculated. When the output from the solar cell has a margin, the converter inlet voltage becomes higher than the maximum efficiency point voltage of the solar cell as is clear from the characteristics of the solar cell in FIG. In this case, the control section works to set the boosted output voltage of the converter higher than the voltage of the DC section. By doing so, the output from the solar cell is preferentially supplied to the compressor side rather than the output from the commercial power source side. Next, when the output from the solar cell is insufficient, power is also supplied from the commercial power source side, but the inlet voltage from the solar cell becomes lower than the maximum efficiency point voltage of the solar cell. By setting the voltage of the boosted output of the converter in the control unit by gradually lowering it according to the decrease in the inlet voltage from the solar cell,
The output from the solar cell is controlled so that the inlet voltage from the solar cell is increased and the inlet voltage from the solar cell is increased so that the inlet voltage is in the vicinity of the maximum efficiency point voltage, and the output from the solar cell can be utilized to the maximum extent.

By the above-mentioned other means, when the compressor is stopped during heating (there may be a heating period even if the operation switch is not turned on, or the compressor is turned off during heating operation), the output from the solar cell Then, the motor in the compressor is operated so as to conduct the open-phase current, and the motor winding is used as a heater to raise the refrigerant temperature in the compressor.

By the other means, the converter inlet voltage and inlet current are detected in the converter controller. When the output from the solar cell has a margin, the inlet voltage from the solar cell is balanced in a state higher than the maximum efficiency point voltage of the solar cell. In this case, cooling and heating are further strengthened as compared with the current indoor air temperature setting. That is, the indoor air temperature setting is controlled to decrease during cooling and to increase during heating.

Further, the indoor unit detects the indoor comfort index by the other means. When the output from the solar cell has a margin, it will be balanced when the inlet voltage from the solar cell is higher than the maximum efficiency point voltage of the solar cell, but in this case the cooling and heating will be strengthened rather than the current indoor air temperature setting. It will be. If the indoor comfort index becomes uncomfortable than the current value by strengthening cooling and heating, it is controlled within the permissible comfort range, the indoor air temperature setting is further lowered during cooling, and it is increased during heating. It will be.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a solar cell driven air conditioner according to one embodiment of the present invention. 2 and 3 are configuration diagrams of a solar cell driven air conditioner according to an embodiment of another invention. For convenience, the same components as in the conventional example are designated by the same reference numerals.

In FIG. 1, 1 is a commercial AC power supply, 2 is a rectifier for rectifying the commercial AC power supply 1, 3 is an inverter for converting the voltage of a DC portion 2o at the outlet of the rectifier 2, and 4 is driven by the inverter 3. A compressor, 5 is an indoor unit for heating and cooling the room, 6 is an outdoor fan driven by the commercial AC power supply 1, and 7 is a solar cell, which is the same as the conventional example shown in FIG. It can be regarded as the same as that shown in FIG. 8
Is a converter that boosts the inlet voltage Di from the solar cell 7 to the outlet voltage Do, and connects the boosted output section 8o of the converter 8 and the DC section 2o at the outlet of the rectifier 2 to form a solar cell drive air conditioner. I am configuring. Reference numeral 9 is a control unit of the converter 8 and has a detection unit for detecting the inlet voltage Di and the inlet current Ii of the converter 8. Therefore, the output of the solar cell 7 (the product of the inlet voltage Di and the inlet current Ii) is also calculated. When the inlet voltage Di from the solar cell 7 is higher than the maximum efficiency point voltage of the solar cell 7 (temporarily set to Va under the condition of a certain ambient temperature and solar radiation amount), the boosted output voltage Do of the converter 8 Is set higher than the voltage of the DC portion 2o, and when the inlet voltage Di from the solar cell 7 is lower than the maximum efficiency point voltage (Va) of the solar cell, the boosted output voltage Do of the converter 8 is According to the decrease of the inlet voltage Di from the solar cell 7, the output voltage D
By gradually decreasing o, the inlet voltage Di from the solar cell 7 is always in the vicinity of the maximum efficiency point voltage (Va).

In FIG. 2, reference numeral 1 is a commercial AC power source, 2 is a rectifier for rectifying the commercial AC power source, and 3 is an inverter for converting the voltage of the DC portion 2o at the outlet of the rectifier 2 into an AC frequency. Reference numeral 4 denotes a compressor driven by the inverter 3, which has a motor 4'built-in and a refrigerant (not shown) enclosed therein. The refrigerant is compressed by energizing the motor 4'during cooling / heating operation. . Especially during heating, since the compressor 4 is in the atmosphere of low outdoor temperature outside the room, the refrigerant may be stored in the compressor 4 and jump out of the compressor 4 together with the oil when the operation is started. Reference numeral 8 is a converter that boosts the inlet voltage Di from the solar cell 7, and connects the output section 8o boosted by the converter 8 and the DC section 2o of the rectifier to form a solar cell driven air conditioner. Then, especially when the compressor 4 is stopped during the heating operation, there is a control method of making the motor 4 ′ of the compressor 4 be open-phase energized by the output from the solar cell 7.

In FIG. 3, reference numeral 5 denotes an indoor unit for controlling the temperature of air (not shown) in the room 10. 2 is a rectifier for rectifying the commercial AC power supply 1; 3 is a DC portion 2o at the outlet of the rectifier 2
Inverters for converting the voltage of 4 are compressors driven by the inverter 3. An outdoor fan 6 is driven by the commercial AC power supply 1. Reference numeral 7 is a solar cell, 8 is a converter for boosting the inlet voltage Di from the solar cell 7, and a solar cell driven air conditioner is formed by connecting the boosted output portion 8o of the converter 8 and the direct current portion 2o of the outlet of the rectifier 2. Make up machine.
Reference numeral 9 is a control unit of the converter 8 and has a detection unit for detecting the inlet voltage Di and the inlet current Ii of the converter 8. Therefore, the output of the solar cell 7 (the product of the inlet voltage Di and the inlet current Ii) is also calculated. When the inlet voltage Di from the solar cell 7 becomes higher than the maximum efficiency point voltage (Va) of the solar cell 7, a method of strengthening cooling and heating rather than the current indoor air temperature setting, that is, setting the indoor air temperature during cooling It has a control method of lowering it and raising it during heating.

Also in FIG. 3, the indoor unit 5 is further added.
The indoor unit 10 is provided with a comfort index detecting means 11. The comfort index is determined by factors such as air temperature, humidity, wall average temperature, and airflow. Air temperature is detected by a temperature thermistor, humidity is measured by a humidity sensor, and wall average temperature is detected by an infrared sensor, etc. (all not shown). To be done. When the inlet voltage Di from the solar cell 7 is higher than the highest efficiency point voltage (Va) of the solar cell 7, the heating / cooling is strengthened more than the current indoor air temperature setting, but the comfort index of the room 10 is the current value. If it is more uncomfortable, it has a control method within the permissible range of comfort, in which the setting of the indoor air temperature is lowered during cooling and raised during heating.

The operation of this embodiment constructed as described above will be described. In the present invention of FIG. 1, when performing the cooling and heating operation, electric power from the solar cell 7 is supplied to the compressor 4 as electric power. When the power from the solar cell 7 side is insufficient, the commercial AC power supply 1 supplies power. The converter control unit 9 detects the converter 8 inlet voltage and inlet current. Moreover, the input from the solar cell 7 (the product of the inlet voltage Di and the inlet current Ii) is calculated. When the electric power from the solar cell 7 is larger than the load of the compressor 4 and there is still a margin, the converter 8 tries to balance the inlet voltage Di in a state of being higher than the highest efficiency point voltage Va of the solar cell 7. The boosted output voltage Do of 8 is applied to the DC unit 2
It is set higher than the voltage of o. By doing so, the output from the solar cell 7 is preferentially supplied to the compressor 4 side over the output from the commercial power supply 1. Solar cell 7
Is the maximum efficiency point voltage Va of the solar cell 7.
If the output from the solar cell 7 is low, the voltage Do of the boosted output of the converter 8 is gradually lowered and set according to the decrease in the inlet voltage Di from the solar cell. The converter is controlled so that the output voltage from the solar cell 7 side is suppressed to reduce the load on the solar cell 7 and the inlet voltage Di of the converter 8 is increased, so that the inlet voltage Di is in the vicinity of the maximum efficiency point voltage Va. 8 is controlled, and the output from the solar cell 7 can be utilized to the maximum.

In the invention of FIG. 2, when the compressor 4 is stopped during heating, that is, during the heating period even when the operation switch is not turned on, or when the compressor 4 is turned off during heating. First, the output from the solar cell 7 causes the motor 4'in the compressor 4 to be open-phase energized. The motor 4'winding is used as an electric heater to raise the temperature of the refrigerant in the compressor.
By doing so, the refrigerant in the compressor does not melt into the oil and is expelled to the outside of the compressor, and problems such as poor lubrication at the time of starting are eliminated.

In another embodiment of FIG. 3, when the cooling / heating operation is performed, the electric power from the solar cell 7 is supplied to the compressor 4 as electric power. When the power from the solar cell 7 side is insufficient, the commercial AC power supply 1 supplies power. The control unit 9 of the converter 8 detects the inlet voltage Di and the inlet current Ii of the converter 8. If there is still a margin even if the power from the solar cell 7 is preferentially used over the commercial AC power supply 1, the inlet voltage Di from the solar cell 7 becomes higher than the maximum efficiency point voltage Va of the solar cell. To try. In that case, the indoor control unit 13 operates to further strengthen the cooling and heating by lowering the indoor air temperature setting from the current set value during cooling and increasing it during heating.

Similarly, in another invention of FIG. 3, when the compressor 4 is energized to perform cooling / heating operation, the indoor control unit 13
In, the indoor air temperature, humidity, wall radiation temperature, etc. are detected by a thermistor, a humidity sensor, an infrared sensor, and the like. The indoor comfort index determined by these values, for example, PM that is generally used in the air conditioning industry
The V (Predicted Average Declaration) value is calculated. For example, this PMV
Depending on the value, a comfortable state that is neither hot nor cold and a comfortable permissible range are determined as one index. When the power from the solar cell 7 can be used with priority over the commercial AC power source 1 and there is still room, the inlet voltage Di from the solar cell 7 is higher than the highest efficiency point voltage Va of the solar cell 7. Try to balance. In this case, the indoor control unit 13 is operated so as to further strengthen the cooling and heating of the room 10. However, when the indoor comfort index is calculated to be more uncomfortable than the current value, it is within the allowable comfort range, and during cooling, the room is indoors. It is controlled so that the air temperature setting is lowered and raised during heating.

[0029]

As is apparent from the above embodiments, according to the solar cell driven air conditioner of the present invention: 1) When the output of the solar cell has a margin compared to the air conditioning load, it is prioritized over commercial AC power. When the output of the solar cell is insufficient, it is replenished from the commercial AC side power, but it is operated near the maximum efficiency of the solar cell, so that the solar cell can be effectively utilized in any case. 2) When the compressor is stopped during heating, the temperature of the refrigerant inside the compressor is raised by the electric power from the solar cell, so the refrigerant inside the compressor is forced out of the compressor without melting into the oil, causing poor lubrication during startup, etc. As well as solving the problem, you can effectively utilize the solar energy you are playing. 3) If the output of the solar cell has a margin compared to the air conditioning load, it will be used preferentially over commercial AC power, but if there is still a margin, it will be set faster by further strengthening the temperature setting value for cooling and heating. The value can be set up and the solar cell can be used more effectively without playing. 4) If the indoor comfort level becomes uncomfortable by further strengthening the temperature setting value for cooling and heating, the temperature setting value will be changed within the allowable comfort range so that the solar cells will be more effective without impairing the comfort level. Can be utilized.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a solar cell driven air conditioner according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a solar cell driven air conditioner according to another embodiment of the present invention.

FIG. 3 is a configuration diagram of a solar cell driven air conditioner according to another embodiment of the present invention.

FIG. 4 is a block diagram of a conventional solar cell driven air conditioner.

[Fig. 5] Characteristics diagram of solar cell

[Explanation of symbols]

 1 Commercial AC Power Supply 2 Rectifier 3 Inverter 4 Compressor 4'Motor 5 Indoor Unit 7 Solar Cell 8 Converter 9 Control Unit 11 Comfort Index Detecting Means

Claims (4)

[Claims] 1. A rectifier for rectifying a commercial AC power source, an inverter for converting a voltage of a DC portion at an outlet of the rectifier, a compressor driven by the inverter, a solar cell, and a converter for boosting an inlet voltage from the solar cell. In a solar cell driven air conditioner that connects the boosted output voltage of the converter and the direct current section, a control section having means for detecting the inlet voltage and the inlet current of the converter is provided, and the inlet voltage from the solar cell is When the voltage is higher than the maximum efficiency point voltage of the battery, the boosted output voltage of the converter is set higher than the voltage of the DC portion, and the inlet voltage from the solar cell is the maximum efficiency point voltage of the solar cell. If it is lower than the above, the voltage of the boosted output of the converter is set to be gradually lowered according to the decrease of the inlet voltage from the solar cell,
A method for controlling a solar cell driven air conditioner in which the inlet voltage from the solar cell is in the vicinity of the maximum efficiency point voltage. 2. An indoor unit, a rectifier for rectifying a commercial AC power supply,
An inverter that converts the voltage of the DC portion at the outlet of the rectifier, a compressor that is driven by the inverter, a solar cell, a converter that boosts the inlet voltage from the solar cell, a boosted output voltage of the converter, and the DC portion. In a solar cell driven air conditioner that connects, when the compressor is stopped during heating operation,
A method for controlling a solar cell driven air conditioner, wherein an open phase current is applied to the compressor by an output from the solar cell. 3. An indoor unit for controlling indoor air temperature, a rectifier for rectifying a commercial AC power source, an inverter for converting a voltage of a DC portion at the outlet of the rectifier, a compressor driven by the inverter, a solar cell, and the sun. A converter for boosting an inlet voltage from a battery, a solar battery drive air conditioner connecting the boosted output voltage of the converter and the direct current portion, and a controller having an inlet voltage of the converter and an inlet current detecting means, When the inlet voltage from the solar cell is higher than the maximum efficiency point voltage of the solar cell, the solar cell driven air conditioner that lowers the indoor air temperature during cooling and raises it during heating to enhance cooling and heating Control method. 4. The indoor unit according to claim 3, wherein indoor comfort index detection means is provided, and as a method for further strengthening cooling and heating, the indoor comfort index becomes uncomfortable than the current value. The method for controlling a solar cell driven air conditioner according to claim 3, wherein the cooling and heating are strengthened within a comfortable permissible range.