JP3030133B2 - Grid-connected photovoltaic power generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grid-connected photovoltaic power generation system that cooperates with a system of electric power obtained from a solar cell and existing commercial power to effectively use energy.

[0002]

2. Description of the Related Art In recent years, a grid-connected solar power generation device that supplies power to load devices in a general home by operating the power generated by a solar cell and the power of an existing commercial power system in parallel. Many have been proposed.

[0003] For example, FIG. 4 shows a system configuration diagram of this type of conventional grid-connected photovoltaic power generator. In this figure, 1 is an AC 100 supplied to a general household.
V, a commercial power supply, 2 a solar cell for generating DC power, 3 an inverter for interconnecting the commercial power supply 1 and the solar cell 2, and 4 a power supply from both the commercial power supply 1 and the solar cell 2. This is a household load device of AC specification that receives supply.

[0004] The inverter 3 converts the DC power of the solar cell 2 into AC and regenerates it into the commercial power 1 or supplies power to the domestic load equipment 4. The home load devices 4 include, for example, an air conditioner, a lighting device, a refrigerator, a washing machine, a television, a vacuum cleaner, and the like, and individually operate independently of the power generated by the solar cells 2.

[0005] Now, from the commercial power supply 1 to the home load equipment 4
Power P _C to be supplied to the inverter - the power supplied from the motor 3 to the home load devices 4 or the commercial power supply 1 P _S, the power consumed by the home load device 4 when the P _L ,

[0006]

(Equation 1)

The following holds.

[0008] Assuming that P _L in the equation is constant at a certain point in time, if the power generated by the solar cell 2 fluctuates depending on the amount of solar radiation, P _S fluctuates,
P _C also shows that the variation in the same manner.

By the way it is not possible to absorb the variation of P _S to control the P _L in Formula 1 since the conventional home load device 4 do not have a common power control function, occurs sudden variation in P _C There was a problem that could not be prevented.

[0010]

The problem to be solved by the present invention is to solve the problem of the fluctuation of the power generated by the solar cell by using an air conditioner using an inverter among the above-mentioned domestic load devices. Is to minimize sudden fluctuations in commercial power and simultaneously suppress the resulting changes in room temperature.

[0011]

SUMMARY OF THE INVENTION The present invention comprises a commercial power supply,
A solar cell, a first inverter for interconnecting the solar cell with the commercial power supply, and a second supplying the power to the compressor motor by receiving the power from the commercial power supply and the solar cell. An air conditioner having an inverter, a power detector for detecting power generated by the solar cell, a temperature sensor for detecting room temperature, and a comparison for comparing a detected value of the temperature sensor with a preset temperature reference. An output of the second inverter is adjusted according to a detection value of the power detector and an output value of the comparator.

More specifically, the output of the second inverter does not fluctuate when the detected value of the power detector shows a fluctuation of about 100 W, but responds instantaneously when it shows a fluctuation of 300 W or more. The output is adjusted, and when the detected value indicates a variation other than these, the output is gradually followed according to the value, and when the detected value of the temperature sensor matches a preset temperature reference. Only the output of the second inverter is adjusted based on the detected value of the power detector, and otherwise, the output of the second inverter is adjusted based on the detected value of the temperature sensor.

[0013]

When the power generated by the solar cell fluctuates, the output of the second inverter built into the air conditioner fluctuates in order to suppress a rapid fluctuation of the commercial power supply. The output of the second inverter is adjusted so as to suppress the fluctuation of the room temperature.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a photovoltaic power generation system according to an embodiment of the present invention;

FIG. 1 is a block circuit diagram showing the configuration of a grid-connected photovoltaic power generator. The same components as those in FIG. 4 are denoted by the same reference numerals.

In FIG. 1, reference numeral 5 denotes an inverter air conditioner as an air conditioner, which internally has a rectifier 51 for converting an AC input to DC, and a DC output of the rectifier 51 which is input and converts it to an AC having a desired frequency. A second inverter 52,
A motor 53 for a compressor, which is driven by the supply of an AC output of the second inverter 52 to produce cool air required for indoor cooling.
Is built-in.

In this example, the rectifier 51 is connected to a connection point between the domestic load 4 and the first inverter 3, and the power generated by the solar cell 2 is supplied to the rectifier 51, the domestic load 4 and the commercial power supply 1. It can be supplied.

Reference numeral 6 denotes a power detector which is connected to the output side of the first inverter 3 and detects fluctuations in the power generated by the solar cell 2. The second inverter is operated in accordance with the detected value of the power detector 6. 52 AC outputs (output frequencies) are adjusted.

Reference numeral 7 denotes a temperature sensor placed in the room where the air conditioner 5 is installed, 8 denotes a temperature reference which can be set manually, and 9 denotes a comparison between the detected temperature of the temperature sensor 7 and the set temperature of the temperature reference 8. The comparator adjusts the AC output of the second inverter 52 according to the comparison result.

In this configuration, the power consumption of the inverter air conditioner 5 is adjusted by changing the frequency of the alternating current supplied from the second inverter 52 in the compressor motor 53.

Normally, the first inverter 3 has a power factor of 1.
, The power detected by the power detector 6 is only active power that does not include reactive power.

The fluctuation of the power generated by the solar cell 2 detected by the power detector 6 is input to a control circuit (not shown) in the second inverter 52 as a detection signal.

The second inverter 52 is connected to the temperature sensor 7
When the generated power of the solar cell 2 increases when the detected value of the temperature detector 8 substantially matches the temperature reference 8, the power detector 6
The control value is increased so that the power consumption of the solar battery 2 is increased by increasing the power consumption of the air conditioner 5 and the power fluctuation of the commercial power supply 1 is reduced as a result.

On the other hand, when the power generated by the solar cell 2 decreases when the detected value of the temperature sensor 7 and the temperature reference 8 substantially match, the second inverter 52 detects the power of the power detector 6. The frequency is reduced according to the value, the power consumption in the air conditioner 5 is reduced, and the decrease in the power generated by the solar cell 2 is compensated for.

The above control will be described more specifically. (1) 100 W of the maximum generated power of the solar cell 2
If the following increase or decrease is ignored, the output of the second inverter 52 is not adjusted. This is because a fluctuation of 100 W or less does not significantly affect the power of the commercial power supply 1.

(2) In the case of an increase or decrease of 300 W or more, the output of the second inverter 52 is instantaneously adjusted to increase or decrease the power consumption of the air conditioner 5. This is because a fluctuation of 300 W or more greatly affects the power of the commercial power supply 1, and if the response is not taken immediately, the system may be damaged.

(3) In the case of an increase or decrease other than the above (1) and (2), the output of the second inverter 52 is gradually adjusted to gradually increase or decrease the power consumption of the air conditioner 5. This is the control.

Thus, for example, if the maximum generated power of the solar cell 2 is 500 W, the fluctuation of the generated power of 100 W or less is ignored, and the fluctuation between 100 and 300 W is a value corresponding to the output of the second inverter 52. The control is performed such that the second inverter 52 instantaneously fluctuates to a corresponding value when the fluctuation is 300 W or more.

During the control of the second inverter 52, the temperature inside the room is detected by the temperature sensor 7 and compared with the preset temperature reference 8 by the comparator 9. As described above, the second inverter 52 is adjusted according to the amount of increase / decrease of the generated power of the solar cell 2, but when they do not match, the output of the comparator 11 is prioritized, and the second inverter 52 is turned on. The output is increased or decreased so that the temperature detected by the temperature sensor 7 matches the temperature reference 8.

In any of these cases, control is performed so that abrupt power fluctuation of the commercial power supply 1 does not occur.

FIG. 2 shows the transition of the electric power of each part and the room temperature during cooling in the block diagram of FIG.
Generated power P _S of the from the top solar cell 2, inverter - Taeakon consumption to power P _L of 5 ', there is shown the output power P _C of the commercial power supply 1, the indoor temperature T, the time.

It should be noted within a period shown in FIG assumed that the power P _L to be consumed by the home load device 4 does not change. T ₀ is the set temperature of the temperature reference 8.

The generated power P _S of the at time t ₁ the solar cell 2 is assumed that decreased. At this time, since the room temperature T and the set temperature T ₀ match, the power detector 6
The second inverter 52 is controlled by the detected value.

[0034] That the inverter - Power P _L 'and the second inverter of Taeakon 5 - reduced by reducing the output frequency of the motor 52 suppress the increase of the output power P _C of the commercial power supply 1.

When the power consumption P _L ′ of the air conditioner 5 decreases, the room temperature T increases, and the difference from the set temperature T ₀ increases. At this time, the output of the comparator 9 has priority over the detector 6, and the power consumption P _L 'of the inverter air conditioner 5 is gradually increased by gradually increasing the output frequency of the second inverter 52. Control to eliminate the difference.

On the other hand, it is assumed that the generated power P _S of the solar cell 2 increases at time t ₂ . At this time, since the room temperature T and the set temperature T ₀ match, the power detector 6
The second inverter 52 is controlled by the detected value.

[0037] That the inverter - Power P _L 'and the second inverter of Taeakon 5 - increased by increasing the output frequency of the motor 52 suppresses a decrease in the output power P _C of the commercial power supply 1.

When the power consumption P _L ′ of the air conditioner 5 increases, the room temperature T decreases, and the difference from the set temperature T ₀ increases. At this time, the output of the comparator 9 has priority over the detector 6, and the output frequency of the second inverter 52 is gradually reduced, so that the power consumption P _L 'of the inverter air conditioner 5 is gradually reduced. Control to eliminate the difference.

[0039] Figure 3 are those set temperature T ₀ and the room temperature T at time t ₁ of FIG. 2 showing a transition of each part of the power and the indoor temperature during cooling when the mismatch, the from the top solar cell 2, the generated power P _S , the power P _L 'consumed by the inverter air conditioner 5, the output power P _C of the commercial power source 1, the room temperature T, and the time.

It should be noted the power P _L to be consumed by the home load device 4 even within the time shown in this figure shall not be changed. T ₀ is the set temperature of the temperature reference 8.

The generated power P _S of the at time t ₁ the solar cell 2 is assumed that decreased. At this time, since there is a difference between the room temperature T and the set temperature T ₀ , the second inverter 52 is controlled by the output of the comparator 9.

[0042] That the decrease in the generated power of the solar cell 2 is compensated in this case the commercial power supply 1 output, power consumption of the air conditioner 5 will continue operating until the indoor temperature T is the set temperature T ₀ as is.

On the other hand, it is assumed that the generated power P _S of the solar cell 2 increases at time t ₂ . At this time, the room temperature T
And the set temperature T ₀ almost coincide with each other, so that the power detector 6
The second inverter 52 gradually reduces the frequency of the inverter air-conditioner 5 according to the detected value, thereby gradually decreasing the power consumption P _L ′ of the inverter air conditioner 5 and gradually decreasing the output of the commercial power supply 1.

[0044]

The present invention provides a commercial power supply, a solar cell, and a first inverter for interconnecting the solar cell to the commercial power supply.
And a second inverter for receiving the electric power from the commercial power supply and the solar cell and supplying the electric power to the compressor motor.
Air conditioner having a power sensor, a power detector for detecting the power generated by the solar cell, a temperature sensor for detecting room temperature, and a comparator for comparing the detected value of the temperature sensor with a preset temperature reference. Since the output of the second inverter is adjusted by the detection value of the power detector and the output value of the comparator, the fluctuation of the power generated by the solar cell is suppressed, and the sudden change of the commercial power is performed. The operation of the air conditioner by grid-connected photovoltaic power generation, which can minimize a significant decrease and reduce the change in the indoor temperature, can be realized.

The output of the second inverter does not fluctuate when the detected value of the power detector shows a fluctuation of 100 W or less, and adjusts its output corresponding to the moment when the detected value shows a fluctuation of 300 W or more. When the detected value indicates a change other than these, the output is gradually followed in accordance with the detected value, thereby reducing the adverse effect of the change in the power generated by the solar cell on the commercial power supply, such as a voltage change, and The effect of minimizing the change in temperature and not impairing comfort is produced.

Further, the output of the second inverter is adjusted based on the detected value of the power detector only when the detected value of the temperature sensor matches a preset temperature reference. At this time, by adjusting the output of the second inverter based on the detection value of the temperature sensor, it is possible to reduce the adverse effect on the commercial power supply and improve the comfort.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a system configuration of a grid-connected solar power generation device of the present invention.

Is a diagram illustrating the power and the change of the room temperature of each part when the [2] in FIG. 1 at time t ₁ between the indoor temperature and the set temperature match.

[3] In FIG. 1 at time t ₁ between the indoor temperature and the set temperature is a diagram showing the power and the change of the room temperature of each part when the mismatch.

FIG. 4 is a block diagram showing a conventional system configuration corresponding to FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Commercial power supply 2 Solar cell 3 1st inverter 5 Inverter air conditioner 52 2nd inverter 6 Power detector 7 Temperature sensor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-130507 (JP, A) JP-A-62-121013 (JP, A) JP-A-59-191841 (JP, A) JP-A-56-118 142339 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H02M ⁷ /42-7/98 F24F 11/00-11/02

Claims (3)

(57) [Claims] 1. A commercial motor, a solar battery, a first inverter interconnecting the solar battery to the commercial power, and a compressor motor receiving electric power from the commercial power and the solar battery. An air conditioner having a second inverter for supplying the power to the power supply, a power detector for detecting power generated by the solar cell, a temperature sensor for detecting room temperature, and a preset value of the temperature sensor. And a comparator for comparing the output value of the second inverter with a detected value of the power detector and an output value of the comparator. 2. The output of the second inverter does not fluctuate when the detected value of the power detector shows a fluctuation of 100 W or less, and adjusts its output corresponding to the moment when the detected value shows a fluctuation of 300 W or more. 2. The grid-connected photovoltaic power generator according to claim 1, wherein when the detected value indicates a variation other than the above, the output is gradually followed in accordance with the value. 3. An output of the second inverter is adjusted based on a detection value of the power detector only when a detection value of the temperature sensor matches a predetermined temperature reference;
At other times, based on the detection value of the temperature sensor, the second
3. The grid-connected photovoltaic power generator according to claim 1, wherein the output of the inverter is adjusted.