JPH04198648A - Air conditioner of two-way power supply - Google Patents

Abstract

PURPOSE:To reduce an electrical current supplied to an AC compressor less than a predetermined value and to prevent a damage caused by an over-current by a method wherein a frequency of an AC power supplied by the AC compressor is varied in response to a sum of an electrical current detected by an AC sensor (C.T) and an electrical current value detected by a DC current sensor. CONSTITUTION:A micro-processor 2 is operated in response to an electrical current IC detected by CT31 and an electrical current IT detected by a DC current sensor 33. It is judged if a control data is received from an indoor device 1 and when the control data is received, it is judged to compare a frequency signal F0 from the indoor device with a frequency (f) of an AC power supplied to the present compressor. If a relation of F0 > f is found, an equation of f = f + 1 is applied and in turn if a relation of F0 < f is found, an equation of f = f-1 is applied and if a relation of F0 = f is applied, the operation proceeds as it is. Then, the AC current IC and the DC current IT are inputted so as to calculate a sum I of these electrical currents. Then, it is judged to have a consumption among the valve of I and the predetermined values 11, 12 and 13. If a relation of I>11 is found, it is set to have a relation of f=0. That is, operation of the compressor is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an air conditioner that can be driven using a commercial AC power source and another DC power source simultaneously.

(b) Conventional technology As a conventional dual power supply drive type air conditioner,
There was one as described in the -146847 publication. The device described in this publication is equipped with a commercial AC power source and a DC power source (solar battery power source), and the air conditioner can be driven using either the commercial AC power source or the DC power source. It was something.

(c) Problems to be Solved by the Invention In such conventional technology, when the output of the DC power source is low enough to operate the air conditioner, the commercial AC power source is used to operate the air conditioner. When the output of the DC power source is sufficient, the output of the DC power source is used to operate the air conditioner.

That is, only either the commercial AC power source or the DC power source is always used to operate the air conditioner. For this reason, when the output of the DC power source is low, the output is cut off, resulting in a low usage efficiency of the DC power source, making it impossible to utilize the DC power source to its full potential.

To address these problems, Japanese Patent Application Laid-Open No. 62-221013
An attempt was made as described in the publication. The system described in this bulletin uses a commercial AC power source and a DC power source (solar cells) together, and when the output of DC power decreases, the compressor is operated by making up for the shortage from the commercial AC power source. However, the method described in this publication did not provide sufficient protection against overcurrent flowing through the compressor. For example, when considering overcurrent to the compressor (the compressor itself is equipped with a bimetal overcurrent protection device, it has the problem of being slow to operate in response to a sudden increase in current). ), a method of directly detecting the current flowing through the compressor is to insert a shunt resistor into the DC circuit and detect it, but if there is a large amount of current flowing through the compressor, the problem is that the voltage drop due to this shunt resistor becomes large. There was a point. Furthermore, when detecting the alternating current supplied to the compressor using a C3T (current transformer), since this alternating current is generally a pseudo-sine wave alternating current, the current waveform detected by the C1T is greatly distorted, making it difficult to detect the current. It is not possible to increase the sensitivity. That is, there was a problem in that the response to a sudden increase in current was slow. Incidentally, this problem similarly occurs when a shunt resistor is used.

Therefore, a method of detecting current by installing a C0T on the primary side of a commercial AC power supply has been generally used, but in this case, it is suitable for an LT power-operated type using a commercial AC power supply.
A dual power source drive type that uses power from another system has the problem that it is not possible to detect the correct current value.

In order to solve these problems, the present invention enables appropriate current detection by detecting the inflow current from each power source.

(D) Means for Solving the Problems The present invention provides DC power, which is a combination of DC power after rectifying and smoothing AC power supplied from a commercial AC power source, and DC power supplied from a DC power source. In a dual power supply drive type air conditioner, the AC power is converted into AC power with a frequency of an alternating current detector that detects alternating current; a direct current detector that detects direct current supplied from the direct current power source;
A protection unit that changes the frequency of AC power supplied to the AC compressor so that the sum of the current detected by the AC current detector and the current detected by the DC current detector does not exceed a predetermined value. It is.

In addition, the DC power, which is a combination of the DC power after rectifying and smoothing the AC power supplied from the commercial AC power source, and the DC power supplied from the DC power source, is converted to an arbitrary voltage and supplied to the DC compressor. , a two-power supply drive type air conditioner configured to change the capacity of the AC compressor by changing the voltage, which has an AC current detector and a DC current detector similarly to the above, and further includes a DC compressor. and a protection unit that changes the DC voltage applied to the

Further, it has an alternating current detector and a direct current detector as described above, and when supplying alternating current of the arbitrary frequency to another alternating current load, the detected alternating current and the direct current detected This device is equipped with a protection unit that cuts off the supply of AC power to other AC loads when the sum of the current detected by the device exceeds a predetermined value.

(E) Function In the dual power supply drive type air conditioner configured in this way,
The frequency of the AC power supplied by the AC compressor is changed based on the sum of the current detected by the AC current detector and the current value detected by the DC current detector.

Further, the voltage of the DC power supplied by the DC compressor is changed based on the sum of the current detected by the AC current detector and the current value detected by the DC current detector.

In addition, when supplying AC power to other AC loads, when the sum of the current detected by the AC current detector and the current value detected by the DC current detector exceeds a predetermined value, the AC power is supplied to the other AC loads. This cuts off the supply of AC power.

(f) Examples Below, examples of the present invention will be explained based on the drawings.
The figure is an electrical circuit diagram (mainly an electrical circuit diagram of an outdoor unit) of a main part of a dual power supply driven air conditioner showing an embodiment of the present invention. In this figure, reference numeral 1 denotes an indoor unit, which is connected to a microprocessor 2 of an outdoor unit via a serial signal circuit 3 through a signal line so that control data can be sent and received.

The data sent from the indoor unit 1 is a frequency signal F that determines the frequency of the pseudo-sine wave AC power supplied to the compressor, and a cooling/heating signal (a signal that switches the four-way valve).
etc. On the other hand, the data sent to the outdoor unit (microprocessor 2 to indoor unit 1) includes outdoor temperature data, the frequency of the AC power currently being output, and data indicating an abnormality when the outdoor unit becomes abnormal. be. 4 to 6 are single-phase induction motors for driving fans installed to blow air to the outdoor heat exchanger, and for returning a portion of the high-temperature refrigerant discharged from the compressor to the evaporator during heating operation. It is a solenoid valve that opens the bypass pipe, and a four-way valve that reverses the refrigeration cycle and switches between cooling operation and heating operation, and is connected between the power lines of the commercial AC power source. A switching contact piece 7 and a switching contact piece 8 are connected in series to the induction motor 4. By switching the switching contact piece 8, the rotation speed of the induction motor 4 can be changed in two steps. The operations of the opening/closing contact piece 7 and the switching contact piece 8 are controlled by the microprocessor 2.

9,]0 is a phototriac and its ON10F
F is controlled by microprocessor 2.

The electromagnetic valve 5 and the four-way valve 6 are operated by the phototriac being 0N10FF.

11, 12, and 13 are temperature sensors, which measure the outside temperature and
The temperature of the outdoor heat exchanger and the temperature of the compressor 14 are detected.

The microprocessor 2 controls the operation of the switching contact 8 based on the outside air temperature and the temperature of the outdoor heat exchanger, and controls the compression $ 14 based on the temperature of the compressor 14 so that this temperature does not exceed a predetermined value. This reduces the frequency of the supplied AC power.

15 is a commercial AC power supply, and AC power supplied from this power supply is given to a rectifier circuit (diode bridge) 19 via a current fuse 26, a varistor 16, a noise filter 17, and a choke coil 18. This rectifier circuit 19
Here, AC power (AC power with an effective value of 100 V) supplied from a commercial AC power supply 15 is voltage-doubled and rectified together with capacitors 2o and 21 to obtain 280 V DC power. 22 is a noise filter, and 23 is a smoothing capacitor. Note that 24 is a current fuse. Reference numeral 25 denotes an inverter circuit, which is composed of six switching elements (transistors, etc.) connected in a three-phase bridge configuration and a drive circuit that individually turns these switching elements into 0N10FF states. The drive circuit switches the switching element to 0N10 in response to the switching signal from the microprocessor 2.
Controls FF. Therefore, each switching element of the inverter circuit 25 is turned on and off by the signal from the microprocessor 2. The microprocessor 2 outputs a switching signal to the inverter circuit 25 so that the AC power of the frequency signal given from the indoor unit is supplied to the compressor 14. This switching signal is PW
This is a switching signal calculated by the microprocessor 2 based on M theory. Therefore, the compressor 14 can be supplied with alternating current power (alternating current using a pseudo sine wave) at any frequency. It goes without saying that the capacity of the compressor can be changed by changing the frequency of this AC power.

A switching power supply 26 lowers the 280V DC power to a low voltage necessary for driving the microprocessor 2 and other electronic circuits.

Note that 27 is a current fuse.

28 is a solar panel (this is an example of a DC power source, and may be replaced with a DC power source such as a battery);
For example, the maximum output is about 600W. (In this embodiment, it is approximately the maximum power consumption of the compressor 14, and is set appropriately according to the maximum power consumption.) 29 is D C/D
C converter and converts the output from the solar panel 28 into 2
It lowers (or increases) the pressure to 90■. Therefore,
The output voltage of this DC/DC converter is always 290
■It shall be maintained as follows. 30 is a diode for backflow prevention, and when the output of the solar battery panel decreases or the power consumption of the compressor 14 increases, the solar battery panel 28
This prevents DC power generated by voltage doubler rectification from flowing back to the solar cell panel 28 when the output of the solar cell panel 28 is insufficient.

31 is C3T (current transformer) (alternating current detector)
This detects the current of the AC power supplied to the rectifier circuit 19, that is, the AC current on the primary side of the commercial AC power supply. The currents detected by C and T are supplied to the microprocessor 2 via an alternating current input circuit 32.

33 is a direct current detector, which detects the direct current supplied from the DC/'DC converter. This detector 33 uses a Hall sensor, and detects the magnitude of the magnetic field generated by the direct current flowing through the power line.
This magnetic field is converted into a current and output. Therefore, direct current can be detected without inserting a shunt resistor into the power line. The current detected by this DC current detector 33 is given to the microprocessor 2 via a DC current input circuit.

In the outdoor unit of the air conditioner configured in this way, the microprocessor 2 detects the current 1c detected by C, T3] and the current I? detected by the DC current detector 33. Based on this, the operations shown in the flowchart of FIG. 2 are performed.

At this time, the current ■. Since the detection voltages of the current I7 and the current I7 are different, the current value when the voltage is unified to either one is calculated and used.

In the flowchart, initial settings of the microprocessor 2 are performed in step S1. Next, in step S2, it is determined whether or not control data has been received from the indoor unit 1. If control data has been received, the frequency signal F from the indoor unit 1 and the current frequency signal F from the indoor unit 1 are supplied to the compressor in step S3. The magnitude relationship between the AC power and the frequency f of the AC power is determined. F
,>f, the process proceeds to step S5 and f=f+1 (that is, the frequency of AC power output to the compressor is increased).
and when F<f, proceed to step S6 and f=f-1
After performing (that is, reducing the frequency of the AC power output to the compressor) and when F e "f, the process directly proceeds to step S7. In step S7, the AC current 1c
and DC current IT are input, and the sum of these currents is calculated as 1. Next, based on steps S, 8 step S9, and step S10, this summer value and predetermined values 11, I2, I3 are determined.
Determine the size relationship of. (There is a relationship of 11>12>13) When I>11, the process proceeds to step Sll and sets f=o.

That is, the operation of the compressor is stopped. When 11≧I>I2, the process advances to step S12 and f=f-2 is set. That is, f set in the previous step is decreased. At this time, since the decrease is set to be larger than the increase in f set in step S5, the output frequency f substantially decreases.

■When 2≧I113, proceed to step 513 and f=f−1
Set to . That is, f set in the previous step is decreased. At this time, since the increase in f set in step S5 is equal to this decrease, f does not substantially increase and the frequency F
, the current value is maintained regardless of the value of . After correcting the value of f based on the current I in this manner, the process proceeds to step 514. In this step S14, the value of f is corrected based on the compressor temperature detected by the temperature sensor 13. This correction performs control such as f=0, decrease of f, prohibition of increase of f, etc., depending on the temperature of the compressor.

Next, the process proceeds to step S15, where the induction motor 4 for blowing air, the solenoid valve 5, the four-way valve 6, etc. are controlled. At this time, control data is also transmitted to the indoor unit 1.

After these operations, the process proceeds to step 516, where a switching signal is output to the inverter circuit 25 so that the AC power at the frequency f is supplied to the compressor 14. This frequency f
After the output of AC power is maintained for a predetermined time (about 1 second),
The process returns to step S2 again, and these steps S are repeated thereafter.

In this way, alternating current ■. and DC current 1. By changing the frequency of the AC power output to the compressor based on Lower the frequency of AC power supplied to the machine to reduce the current flowing to the compressor, ■
When 2≧1>13, it is possible to prevent an increase in the frequency of the AC power supplied to the compressor, thereby preventing an increase in the current flowing through the compressor.

FIG. 3 is an electrical circuit diagram of an air conditioner showing another embodiment of the present invention. This diagram differs from the electrical circuit diagram shown in Figure 1 in that a DC brushless motor is used for the compressor. Note that explanations of the same components as shown in FIG. 1 will be omitted. 40 is a compressor driven by a three-phase DC brushless motor, and energization to each phase is switched from the inverter passage 25 in accordance with the rotation angle of the compressor 40. 41 is a switching power supply whose output is supplied to the inverter circuit 25. This output voltage is controlled by a signal from the microprocessor 2. Reference numeral 42 denotes an energization switching device that detects changes in the DC voltage applied to each phase of the compressor 40 (changes due to the back electromotive force caused by the permanent magnet) and calculates the rotation angle of the compressor 40. 0N10FF of the switching element of the inverter circuit 25 is controlled so that current can be applied to the appropriate phase. Note that this energization switch 42 is connected to the microprocessor 2.
The operation is started by a signal from. Therefore, when the energization switch 42 is operating, the rotation speed, that is, the capacity of the compressor can be changed by controlling the output voltage of the switching power supply 41.

In the outdoor unit of the air conditioner configured in this way, the operation of the microprocessor 2 is almost the same as the operation explained using the flowchart shown in FIG. The difference is that as the frequency changes to the rotational speed, the operation in step S16 changes to "output to the switching power supply 41 a signal that outputs a DC voltage that provides a rotational speed of f." In reality, since a signal with frequency F is sent from the indoor unit 1, processing is performed at the same frequency from step 52 to step S12, and in step S13, the number of revolutions corresponding to the frequency is calculated. A signal is output to the switching power supply 41 to output a voltage from which the number of revolutions can be obtained.

In this way, by changing the voltage of the DC power output to the compressor based on the AC current IC and the DC current 7, and changing the rotation speed of the compressor, the current flowing through the compressor will become I>T.
When I, the compressor operation is stopped, when 11≧I11, the voltage of the DC power supplied to the compressor is lowered to lower the current flowing to the compressor, and when I2≧1>13, the current is supplied to the compressor. This prevents the voltage of the DC power from increasing, thereby preventing an increase in the current flowing to the compressor.

FIG. 4 is an electrical circuit diagram of an air conditioner showing still another embodiment. In agreement with the electric circuit diagram shown in FIG. 1, the AC power output from the inverter circuit 25 is
0 to 52 to the compressor 14. The switching operation of the switching contacts 50 to 52 is controlled by the microprocessor 2.

Therefore, by switching the switching contacts 50 to 51, it is possible to switch between supplying the AC power output from the inverter circuit 25 to the compressor 14 or supplying it from the terminal ACOUT to another AC load.

When the switching contacts 50 to 52 are on the compressor 14 side (as shown in FIG. 4), the electrical circuit becomes substantially the same as the electric circuit shown in FIG. 1, and the flowchart shown in FIG. Actions based on this are performed.

The operation of the microprocessor 2 when the switching contacts 50 to 52 are on the ACOUT side is to first change the frequency F to "F".
= 50 (for areas where the frequency of commercial AC power supply is 50 hertz).Furthermore, step 89 to step 5.
13 is deleted, and when the current value exceeds a predetermined value, the current supply to other loads is cut off. Next, the microprocessor 2 supplies an ON10 FF signal such that single-phase AC power is obtained from the inverter circuit 25 to the switching element. In addition, when obtaining single-phase AC power, a single-phase bridge (a bridge with four switching elements) is sufficient, so among the six switching elements of the inverter circuit 25, the switching contacts 51.5
Four switching elements are selected to form a single-phase bridge so that single-phase AC power can be obtained from the two switching elements. Therefore, the microprocessor controls these four switching elements ON10FF and keeps the remaining two switching elements OFF.

In the air conditioner configured in this way, the current flowing to other loads can be controlled within a predetermined value as in the previous embodiment, and overcurrent can be prevented from flowing to the inverter circuit 25 and destroying the switching elements. can do.

In the above embodiment, the current 11 for cutting off (stopping) the output from the inverter circuit 25 is set based on the allowable current of the inverter circuit 25.

As yet another embodiment, when there is a limit to the current supplied from the commercial AC power source, the AC current detector 31 detects the AC current ■. A limit is placed on the compressor capacity (frequency f of AC power) based on the following.

FIG. 5 is a flowchart of this process, which is added before step 514 of the flowchart shown in FIG. In this flowchart, steps 851 to S53
AC current IC and current I detected by AC current detector 31 at
4, I5.16 (14>15>16) and steps 554 to S57 are performed. In step 554, f=0 and the supply of AC power to the compressor is stopped. That is, the current IC from the commercial AC power supply is prevented from exceeding the current 14. In step 555, f=f
-2 to lower the frequency supplied to the compressor. At this time, if the operations in steps S12 and S13 are performed, the frequency f will be reduced by 4 or 3. Step S5
In step 6, it is determined that the current I is 1>13, and the previous step 51
3. Determine whether or not step 3 has been performed. If step 513 has been performed, f=f-1 is not performed in step S57. If not, step 557 is performed to reduce the frequency f by 1. That is, when step S53 is satisfied, the frequency f is not decreased and the frequency f is prohibited from increasing.

With this configuration, the maximum current can be obtained from the commercial AC power supply, and this current and the current from the solar panel can be combined and supplied to the compressor.

Specifically, when setting up such an air conditioner in a general household, the current that can be supplied to the air conditioner from a commercial AC power source is limited to 20A. (The unit of one breaker is 20A.
) Therefore, the compressor can only be supplied with a maximum of 2 OA, but by installing a solar panel, the current supplied from the solar panel can be added to 2 OA, increasing the maximum capacity of the compressor. It becomes possible to use it. In other words, while using both the current from the commercial AC power supply and the current from the solar panel, the operating capacity of the compressor (discharge It is possible to control the electric power of the helmet.

It goes without saying that control is performed based on the sum of the current 1c and the current IT.

(G) Effects of the Invention As described above, the present invention provides DC power, which is a combination of DC power after rectifying and smoothing AC power supplied from a commercial AC power source, and DC power supplied from a DC power source. In a dual power supply drive type air conditioner, the AC power is converted into AC power with a frequency of an alternating current detector that detects alternating current; a direct current detector that detects direct current supplied from the direct current power source; a current detected by the alternating current detector; and a current detected by the direct current detector. and a protection unit that changes the frequency of the AC power supplied to the AC compressor so that the sum of the AC power does not exceed a predetermined value. Damage to the compressor due to overcurrent can be prevented.

Furthermore, when a DC compressor is used, damage to the DC compressor due to overcurrent can be prevented by changing the DC voltage supplied to the DC compressor using a protection section.

Furthermore, even when alternating current power is supplied to other loads, the output of this alternating current power can be suppressed to prevent damage during conversion to alternating current power.

[Brief explanation of the drawing]

Fig. 1 is an electrical circuit diagram of the main parts of a dual power supply driven air conditioner showing an embodiment of the present invention, Fig. 2 is a flowchart showing the main operations of the microprocessor shown in Fig. 1, and Fig. 3 is a FIG. 4 is an electrical circuit diagram of an air conditioner showing another embodiment of the present invention. FIG. 5 is an electrical circuit diagram of an air conditioner showing still another embodiment of the present invention. FIG. FIG. 1... Indoor unit, 2... Microprocessor,
14...Compressor, 15...Commercial AC power supply, 25...
・Inverter circuit, 28...Solar battery panel, 29・
...DC/DCC/formula-ta, 31...AC current detector, 33...DC current detector, 41...Switching power supply, 50-52...Switching contact piece.

Claims (3)

[Claims] (1) AC compression by converting DC power, which is a combination of DC power after rectifying and smoothing AC power supplied from a commercial AC power source, and DC power supplied from a DC power source, into AC power of an arbitrary frequency. an AC current detector for detecting an AC current supplied from the AC power source in a dual power supply driven air conditioner configured to change the frequency and change the capacity of the AC compressor; a DC current detector that detects the DC current supplied from the DC power source; and a DC current detector that detects the DC current supplied from the DC power source; A dual power source driven air conditioner characterized by comprising a protection unit that changes the frequency of AC power supplied to an AC compressor. (2) DC power, which is a combination of DC power after rectifying and smoothing AC power supplied from a commercial AC power source and DC power supplied from a DC power source, is converted to an arbitrary voltage and supplied to the DC compressor. In a dual power supply driven air conditioner configured to change the capacity of the AC compressor by changing the voltage, an AC current detector for detecting the AC current supplied from the AC power supply, and the DC power a DC current detector that detects the DC current supplied from the source; and a DC current detector configured to control the DC compressor so that the sum of the current detected by the AC current detector and the current detected by the DC current detector does not exceed a predetermined value. What is claimed is: 1. A dual power supply drive type air conditioner characterized by comprising a protection unit that changes the voltage of DC power applied to the air conditioner. (3) AC compression by converting DC power, which is a combination of DC power after rectifying and smoothing AC power supplied from a commercial AC power source, and DC power supplied from a DC power source, into AC power of an arbitrary frequency. In a dual power source driven air conditioner configured to supply AC power to the machine and change the frequency to change the capacity of the AC compressor, when supplying AC power of the arbitrary frequency to another AC load, a frequency fixing unit that fixes the frequency of the AC power; an AC current detector that detects the AC current supplied from the AC power source; a DC current detector that detects the DC current supplied from the DC power source; It is characterized by comprising a protection unit that cuts off the supply of AC power to other AC loads when the sum of the current detected by the AC current detector and the current detected by the DC current detector exceeds a predetermined value. A dual power supply driven air conditioner.