JPH09284985A - Power supply apparatus in air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect an open phase with a simple construction which does not include a special circuit, etc., for the detection of the open phase. SOLUTION: The electric circuit of an air conditioner consists of a 3-phase AC power supply (PS) and an indoor control unit (50) and an outdoor control unit (30) which are connected to the AC power supply (PS). The power is supplied to the indoor control unit (50) through the phase S and phase T and supplied to the outdoor control unit (30) through the phase R and phase S. If one phase is opened, at least one of the indoor control unit (50) and the outdoor control unit (30) is put into a defective operation state and hence the open phase can be detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power protection device for an air conditioner, and more particularly, to improvement of measures against open-phase power source power.

[0002]

2. Description of the Related Art Heretofore, there has been known an air conditioner having an electric circuit connected to a three-phase AC power source through power supply wiring, as disclosed in Japanese Patent Laid-Open No. 8-37383. As one type of compressor provided in the refrigerant circuit of this type of air conditioner, there is one in which the operating frequency is variable by an inverter circuit. That is, the three-phase AC from the power supply is full-wave rectified, converted into DC once, smoothed, then converted into AC of a desired frequency, and the voltage is applied to the compressor motor. I have to.

In this type of electric circuit, when one of the three-phase alternating current from the power source is open, a ripple voltage is generated in the direct current portion of the inverter circuit. I am trying to recognize the missing phase. Specifically, both the indoor control means for controlling the indoor unit and the outdoor control means for controlling the outdoor unit are connected to the R phase and the S phase of the three phases, and when a phase loss occurs, ripples occur in the DC portion. Since a voltage will be generated, the open phase is recognized by detecting this. Then, when such a phase loss occurs, the power supply is stopped in order to prevent the capacitor provided in the inverter circuit from being destroyed.

[0004]

By the way, in such a structure that protects the circuit when there is a phase loss, a dedicated detection circuit for detecting the ripple voltage is required, and this detection signal is also required. A control unit for processing is also required. As a result, the number of constituent parts is increased and the configuration is complicated, resulting in a large increase in manufacturing cost.

The present invention has been made in view of this point, and an object of the present invention is to eliminate the need for a special detection circuit for detecting a phase loss and to detect a phase loss with a simple configuration. And

[0006]

In order to achieve the above object, the present invention is designed so that at least one of the indoor control means and the outdoor control means becomes inoperable when any one of the three phases is out of phase. The power supply wiring is connected to each control means.

[0007] Specifically, in the invention according to claim 1, the indoor control means (50) for controlling the indoor unit and the outdoor control means (30) for controlling the outdoor unit are provided with an alternating current of a first phase to a third phase. (R,
Power supply wiring (60R, 60) to the three-phase AC power supply (PS) that supplies S, T)
It is premised on an air conditioner having an electric circuit connected via (S, 60T). And the indoor control means (50)
To the first power supply wiring (60) for supplying the alternating current (S) of the first phase.
S) and the second phase AC current (T) is fed to the AC power supply (PS) via the second power supply wire (60T), while the outdoor control means (30) is connected to the first power supply wire (60S). Also, one of the second power supply wiring (60T) and the third power supply wiring (60R) for supplying the third-phase AC current (R) is connected to the AC power supply (PS).

With this structure, the indoor control means (50) is
AC current of the 1st phase and 2nd phase by power supply wiring (60S, 60T)
While (S, T) is fed, the outdoor control means (30) uses the power supply wiring (60R, 60S, 60T) to connect the alternating current of one of the first and second phases and the alternating current of the third phase. The current (R) is supplied. When one of these three phases is missing, at least one of the indoor control means (50) and the outdoor control means (30) becomes inoperable. If such a situation occurs, for example, if the power supply circuit is cut off,
It is possible to avoid damage to the circuit due to the occurrence of open phase (for example, damage to the capacitor due to the occurrence of ripple voltage),
Circuit protection against phase loss can be performed without requiring a special voltage detection circuit or the like.

The invention according to claim 2 is the above-mentioned claim 1.
It is an improvement for surely obtaining the operation according to the described invention. Specifically, in the power supply device for an air conditioner according to claim 1, a two-phase power supply to the indoor control means (50) is provided between the first and second power supply wirings (60S, 60T). A capacitor (C4) is provided to bypass the current flowing through the first and second power supply wirings (60S, 60T) to the indoor control means (50) when one of them has a phase loss.

In the circuit configuration according to the invention described in claim 1, when one of the two phases supplied to the indoor control means (50) is open, the indoor control means (5
There is a possibility that the remaining one phase that has not been supplied to 0) will be supplied to the indoor control means (50) via the outdoor control means (30) and other line circuits (eg noise filter circuit). There is. Then, in this case, the indoor control means (50) may emit an unnecessary abnormality determination signal. In the invention according to claim 2, the indoor control means (5
By providing a capacitor (C4) for bypassing the current to 0), unnecessary power supply to the indoor control means (50) in such a situation (originally, from one phase dedicated to power supply to the outdoor control means) The electric power supply is not performed, and the inoperable state as described in the operation according to the invention described in claim 1 is reliably obtained.

According to a third aspect of the invention, when a phase loss occurs,
By utilizing the fact that the phase of the interphase voltage is deviated, the phase is judged by detecting this deviance. Specifically, in the power supply device for an air conditioner according to claim 1, first zero-cross detection means (65) for detecting a zero-cross point of interphase voltage between two phases connected to the indoor control means (50). And the second zero-cross detecting means (66) for detecting the zero-cross point of the interphase voltage between the two phases connected to the outdoor control means (30), and the outputs of the respective zero-cross detecting means (65, 66), Open phase determination means (43) for performing open phase determination when the phase difference at the zero cross point is different from the predetermined phase difference
It is configured to include and.

With this configuration, each zero-cross detecting means (65, 66) detects the deviation of the phase difference of the inter-phase voltage due to the occurrence of the phase loss as the deviation of the zero-cross point. Then, the phase loss determining means (43) determines that the phase difference at each zero-cross point is different from the predetermined phase difference, and the phase loss has occurred. This makes it possible to more reliably determine the occurrence of the open phase.

According to a fourth aspect of the present invention, in the power supply device for an air conditioner according to the third aspect, the open-phase determining means (43) determines that the phase difference at each zero-cross point is smaller than a predetermined phase difference. It is configured to perform the open phase determination.

With this configuration, the phase difference between the interphase voltages is deviated due to the occurrence of the phase loss, and the phase difference at each zero-cross point becomes smaller than the predetermined phase difference. Is detected, and the open-phase determination is performed accordingly.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) A first embodiment of the present invention will be described in detail below with reference to the drawings.

As shown in FIG. 1, the electric circuit of the air conditioner according to this embodiment has an outdoor control unit (30) as an outdoor control means connected to a three-phase AC power source (PS) and an indoor room as an indoor control means. The indoor control unit (50) includes a control unit (50), the outdoor control unit (30) controls an induction motor (CM) of a compressor included in an outdoor unit (not shown), and the indoor control unit (50) is an indoor unit (not shown). It controls the indoor fan and the like provided in the.

The configuration for controlling the induction motor (CM) of the compressor will be described below. As shown in FIG.
(10) is a control device for an induction motor (CM) of a compressor provided in an outdoor unit of an air conditioner, including a power conversion circuit (20) and the outdoor control unit (30), and a power source (PS ) Supplies control power to the induction motor (CM) via the power conversion circuit (20).

The power conversion circuit (20) converts the three-phase AC power supplied from the power supply (PS) into controlled three-phase AC power, and includes a rectifying circuit (21) and a smoothing circuit (2).
2) and an inverter circuit (23). And
The rectifier circuit (21) includes six diodes (d1, d1,
…) And a power supply (P
A diode module connected to S) that performs full-wave rectification on AC from the power supply (PS).

The smoothing circuit (22) smoothes the direct current that has been full-wave rectified by the rectifying circuit (21). The smoothing circuit (22) is provided with a reactor (2L) and has a smoothing capacitor (2C). 2a) and a resistor circuit (2b) having a discharge resistor (2R) are connected to the power supply line (2P, 2
N). The smoothing circuit (22) has a DC section current, that is, an induction motor (C
A current transformer (CT) that is a current detector that detects a motor current that is the current of M) is provided in the power supply line (2N).

The inverter circuit (23) is a transistor including six power transistors (Tr, Tr, ...).
A smoothing circuit (22) is a transistor module that converts a smoothed direct current into an alternating current, and is connected to an induction motor (CM) to supply three-phase AC control power to the induction motor (CM). I have. A freewheeling diode (d2, d2, ...) Is connected between the emitter and collector of the power transistor (Tr, Tr, ...), and the power transistor (Tr, Tr ,. It is turned on and off by 30).

The outdoor control unit (30) is provided with a drive circuit (31) and a microcomputer (40) while a current signal is input from a current transformer (CT). The drive circuit (31) outputs a drive signal to the power transistors (Tr, Tr, ...) so that the power transistors (Tr, Tr, ...) PWM-modulate the DC portion voltage smoothed by the smoothing circuit (22). To do. An air conditioning load signal such as the room temperature is input to the microcomputer (40), and a speed control means (41) and an optimum control means (42) are provided.

The speed control means (41) receives an air conditioning load signal such as the room temperature, and derives the supply frequency of the induction motor (CM) which is the operating frequency of the compressor in response to the air conditioning load signal. Then, the control signal is output to the drive circuit (31) so as to achieve this supply frequency.

That is, the speed control means (41) controls the drive of the inverter circuit (23) so that the supply frequency and the supply voltage of the induction motor (CM) change based on the preset reference voltage frequency characteristic. A control signal for controlling the supply frequency of the induction motor (CM) to control the induction motor (CM) at a variable speed is output to the drive circuit (31). Then, the drive circuit (31) outputs the drive signal to the inverter circuit (23) of the power conversion circuit (20) based on the control signal.

The optimum control means (42) drives an adjustment signal for adjusting the supply voltage of the induction motor (CM) so that the supply voltage of the induction motor (CM) is minutely changed by a predetermined change amount to minimize the motor current. Outputting to the circuit (31). Then, the drive circuit (31) outputs the drive signal to the inverter circuit (23) of the power conversion circuit (20) based on the adjustment signal.

Next, a circuit configuration for supplying electric power to the outdoor control unit (30) and the indoor control unit (50), which is a feature of this embodiment, will be described. The outdoor control unit (30) is supplied with alternating current from the R and S phases of the power source, while the indoor control unit (50) is supplied with alternating current from the S and T phases of the source power. Has become. Specifically, the outdoor control unit (30) is through the R-phase power wiring (60R) and the S-phase power wiring (60S), and the indoor control unit (50) is through the S-phase power wiring (60S) and the T-phase power wiring ( It is connected to the power supply (PS) via 60T). That is, the S-phase power wiring (60S) is branched into an outdoor wiring (60S-1) and an indoor wiring (60S-2) from the middle of the wiring, and the outdoor wiring (60S-1) is connected to the outdoor control unit (30S). ), The indoor side wiring (60S-2) supplies power to the indoor control unit (50), respectively. With such a configuration, the outdoor control unit (30) operates by being supplied with both R-phase and S-phase currents, and the indoor control unit (50) operates in the S-phase and T-phase.
The phase currents are activated by being supplied together (note that the S phase has a phase delay of 120 ° with respect to the R phase and the T phase has a phase delay of 120 ° with respect to the S phase).

-Control Operation of Induction Motor (CM)-Next, the control operation of the above-mentioned induction motor (CM) will be described.

First, in the state where the power supply (PS) is turned on and the switching circuit (11) is turned on, when an operation command such as a cooling operation is output from a remote controller (not shown), the microcomputer (40) receives this operation command. And speed control means (41)
Outputs a control signal. This control signal is sent to the drive circuit (31)
Outputs the drive signal to the inverter circuit (23),
The power transistors (Tr, Tr, ...) are turned ON / OFF.

On the other hand, the three-phase AC power from the power source (PS) is full-wave rectified by the rectifier circuit (21) and converted into direct current, then smoothed by the smoothing circuit (22), and then the inverter circuit ( 23) is output. And six power transistors (Tr, Tr,...) Of the inverter circuit (23).
Converts DC into AC and applies PWM modulation to apply a predetermined supply voltage to the induction motor (CM).

Further, an air conditioning load signal such as an indoor temperature is inputted to the microcomputer (40), and the speed control means (41)
Derives the supply frequency of the induction motor (CM), which is the operating frequency of the compressor, in response to the air conditioning load signal,
A control signal is output to the drive circuit (31) so as to have this supply frequency. That is, the speed control means (41) controls the drive of the inverter circuit (23) so that the supply frequency and the supply voltage of the induction motor (CM) change based on the preset reference voltage frequency characteristic. And the drive circuit (31) outputs a drive signal to the inverter circuit (23) based on the control signal. As a result, the induction motor (CM) rotates corresponding to the air-conditioning load.

When the induction motor (CM) is rotating, the optimum control means (42) slightly changes the supply voltage of the induction motor (CM) by a predetermined fluctuation amount so that the motor current is minimized. The adjustment signal is output to the drive circuit (31). Then, the drive circuit (31) outputs a drive signal to the inverter circuit (23) based on the adjustment signal so that the induction motor (CM) rotates at the most efficient minimum current value.

-Out-of-phase operation-Next, the operation when one of the three phases of the power supply is out of phase will be described.

If the R phase out of the three phases is missing,
No current flows through the R-phase power wiring (60R), and power is supplied to the outdoor control unit (30) only from the S-phase power wiring (60S). For this reason, power supply to the outdoor control unit (30) is not normally performed, and the outdoor control unit (30) becomes inoperable. When this occurs, for example, each switch of the switching circuit (11) is turned on.
By performing FF, power supply to the power conversion circuit (20) is stopped. This can prevent a ripple voltage from being generated in the DC portion of the power conversion circuit (20) and destroy the smoothing capacitor (2C) of the capacitor circuit (2a).

Further, even when the S phase or the T phase out of the three phases is lost, the power supply to the outdoor control unit (30) or the indoor control unit (50) is not normally performed and the operation is disabled, and switching is performed. Protects the circuit by turning off the circuit (11).

As described above, according to the configuration of the present embodiment, a dedicated detection circuit for detecting the ripple voltage, such as the conventional one for determining the open phase by detecting the ripple voltage, and this detection signal are used. The control unit for processing is not required, and the circuit can be protected against the open phase even when any one of the three phases has the open phase with a simple configuration. For this reason, it is possible to reduce the number of components and simplify the configuration, and it is possible to reduce the manufacturing cost.

(Second Embodiment) Next, a second embodiment according to the present invention will be described in detail with reference to the drawings. In the above-described first embodiment, the indoor control unit (50) operates when the S phase or the T phase is open, and the indoor control unit (5
On the remote controller (not shown) connected to 0), there is a possibility that an abnormal code different from that at the time of phase loss will be displayed. This form is
This is for surely preventing this. More specifically, FIG. 2 shows each power supply wiring (60R, 60R) to each of the outdoor and indoor control units (30, 50) in the first embodiment described above.
FIG. 6 is a circuit diagram schematically showing a connection state of (60S, 60T). In this way, the line-to-line capacitors (C1, C2, C3) that function as noise filters between each power supply wiring (60R, 60S, 60T).
Is provided. And when the S phase is missing, originally,
Power is supplied to the indoor control unit (50) only from the T phase, but in reality, as shown by the solid arrow in Fig. 2, the line capacitor (C1) between the R phase and the S phase and the outdoor control are performed. An R-phase current flows through the indoor wiring (60S-2) through the unit (30). That is, the indoor control unit (50) is supplied with power of T phase and R phase. On the other hand, when the T phase is out of phase, the indoor control unit (50) is originally supplied with power only from the S phase, but in reality, as shown by the broken line arrow in FIG. An R-phase current flows through the indoor side wiring (60S-2) through the line capacitor (C3) between the T-phases. That is, the indoor control unit (50) is fed with the S-phase and the R-phase. In such a situation, the indoor control unit (50) may perform an unnecessary operation or an erroneous operation.

Therefore, in the present embodiment, as shown in FIG.
A new line bypass capacitor (C4) for current bypass is provided between the indoor side wiring (60S-2) of the S-phase power wiring (60S) and the T-phase power wiring (60T). According to this, the current of the R phase, which was flowing through the indoor control unit (50) when the S phase or the T phase was lost, was changed to the indoor control unit (50) as shown by the arrow in FIG.
Is bypassed, and the current is passed through the line capacitor (C4), and no R-phase current flows through this indoor control unit (50). In other words, by providing a line capacitor (C4) between the S phase and the T phase to reduce the impedance and reduce the interphase voltage between the S phase and the T phase during the open phase, the indoor control unit (50) and this The remote control connected to the indoor control unit (50) is prevented from operating, and the unnecessary abnormal code display as described above can be prevented.

As described above, according to the configuration of the present embodiment, the malfunction (the output of the unnecessary abnormal code) at the time of phase loss can be avoided with a very simple configuration such as the provision of one capacitor (C4). It is possible to improve the sex.

(Third Embodiment) A third embodiment of the present invention will be described in detail below with reference to the drawings. In this example, the open phase can be detected more reliably.

First, as shown in FIG. 4, the phase-to-phase voltage waveforms in a state in which none of the phases are open-phase have a phase difference of 120 ° C. and the same maximum voltage value (for example, 200 V). It has a waveform.

If the S phase is missing,
As shown in FIG. 5, the R-phase and S-phase inter-phase voltage waveforms (shown as R-S in FIG. 5) and the S-phase and T-phase inter-phase voltage waveforms (shown as S-T in FIG. 5) are zero crossings. Point (point where voltage becomes 0)
The phase difference of is almost eliminated. This is R phase and T
This is because the interphase voltage of each phase is distributed among the above-mentioned phases.

In this way, the microcomputer indicates that the phase difference between the inter-phase voltage waveforms (R-S, S-T) has almost disappeared and the phase difference at the zero cross point of each waveform has become smaller than the predetermined phase difference. (40) detects it, and the open phase is determined by this.

Hereinafter, a specific configuration for performing this phase loss determination and its determination operation will be described. As shown in FIG. 6, a zero-cross detection circuit (65) and a protection device input circuit (66) are connected to each power supply line (LR, LS, LT). The zero-cross detection circuit (65) is connected to the S-phase and T-phase power supply lines (LS, LT) by wiring (65a, 65b), and the outdoor control unit ( The control signal is transmitted (inside / outside transmission) between the indoor control unit (50) and the indoor control unit (50). Further, the zero-cross detection circuit (65) outputs an ON signal as a rectangular wave while the absolute value of the interphase voltage between the S phase and the T phase exceeds a predetermined value, and an OFF signal as a rectangular wave when the absolute value does not exceed the predetermined value. Has become. That is, this rectangular wave is in the OFF state near the zero crossing point of the interphase voltage between the S phase and the T phase.

On the other hand, the protective device input circuit (66) is for judging the abnormality of the refrigerant discharge pipe temperature and the refrigerant discharge pressure of the compressor, and the R (phase) and S (phase) power supplies are connected by the wirings (66a, 66b). It is connected to the line (LR, LS). Further, the wiring (66a) connected to the R-phase has a protective contact (67) which is turned on / off in response to an output signal from a protective device (not shown) such as a temperature sensor or a pressure switch provided on the refrigerant discharge side of the compressor. ) Is provided. And this protection device input circuit (66)
Outputs an ON signal as a rectangular wave while the absolute value of the interphase voltage between the R phase and the S phase exceeds a predetermined value, and outputs an OFF signal as a rectangular wave when the absolute value does not exceed a predetermined value. That is, R phase and S
This rectangular wave is in the OFF state near the zero crossing point of the interphase voltage with the phase. Further, in the protective device input circuit (66), the protective device operates and the protective contact (67) is OF
When F, the generation of the rectangular wave is stopped.

Then, these zero-cross detection circuits (65)
And the rectangular wave signal from the protection device input circuit (66) is transmitted to the open phase determination means (43) provided in the microcomputer (40),
The phase loss determination means (43) makes a phase loss determination by comparing these rectangular waves (details will be described later).

Next, a description will be given of the phase loss determination operation in such a configuration. This determination operation is performed at the time when the rectangular wave signal from the zero-cross detection circuit (65) is turned from ON to OFF (the absolute value of the interphase voltage between the S phase and the T phase decreases from a predetermined value or more to a predetermined value or less). The state of the rectangular wave signal from the protection device input circuit (66) (whether it is in the ON state or the OFF state) at the time point) is detected, and thereafter, the phase from the protection device input circuit (66) after the phase of 60 ° is detected. The state of the rectangular wave signal is detected. Hereinafter, for the sake of simplification of description, the former detection is referred to as a first detection operation, and the latter (phase 60 °).
The latter detection is referred to as a second detection operation.

In a normal state in which no phase loss has occurred, FIG.
(The upper side of FIG. 7 shows the inter-phase voltage waveform between S-T and its rectangular wave, and the lower side shows the inter-phase voltage waveform between R-S and its rectangular wave). During operation (Fig. 7
(At the position of the broken line on the left side of the)
The rectangular wave signal from the protection device input circuit (66) is in the OFF state in the second detection operation (the position of the broken line on the right side of FIG. 7). When such a state is detected by the phase loss determination means (43), it is determined to be a normal state in which no phase loss has occurred.

When the S phase is lost, as shown in FIG. 8, the protective device input circuit (6
The rectangular wave signal from 6) is in the ON state, and the rectangular wave signal from the protective device input circuit (66) is in the ON state even in the second detection operation. In such a state, the phase loss determination means (4
When detected by 3), it is determined that the S phase open phase has occurred, and the remote control displays the open phase occurrence. That is, when the open phase of the S phase occurs, as described above, the R phase and the S phase
Since there is almost no phase difference between the interphase voltage waveforms of the phases and the interphase voltage waveforms of the S phase and the T phase, the signal is detected in such a state, which facilitates the open phase judgment. You can When the phase difference between the R-phase and S-phase inter-phase voltage waveforms and the S-phase and T-phase inter-phase voltage waveforms is zero during this phase loss, the protective device input circuit in the first detection operation is performed. Since the rectangular wave signal from (66) is in the OFF state, it is preferable that the phase loss determining means (43) determine the occurrence of the phase loss even in such a situation.

When the protective device is in operation, the protective contact (67) is in the OFF state, and the protective device input circuit (66) does not output a rectangular wave signal. For this reason,
As shown in FIG. 9, the rectangular wave signal from the protection device input circuit (66) is OFF in both the first detection operation and the second detection operation.
In this state, it can be recognized that the protective device is in an operating state. That is, the presence or absence of the above-described phase loss and the operating state of the protective device can be accurately recognized by the same circuit.

As described above, according to this embodiment, the open phase determination is performed by comparing the inter-phase voltage waveforms, so that the open phase can be detected more accurately.

The inverter circuit (23) in each of the above-described embodiments has six power transistors (Tr, Tr,
...) was used, but in the present invention, six IGBTs (Insulat
ed Gate Bipolar Transistor) may be used.

[0051]

As described above, according to the present invention, the following effects can be obtained. According to the first aspect of the present invention, in the air conditioner having an electric circuit for supplying power from the three-phase AC power source to the indoor control means and the outdoor control means, the indoor control means includes the first-phase and second-phase AC currents. To
By supplying one of the first phase and the second phase alternating current and the third phase alternating current to the outdoor control means, if one of the three phases is out of phase, the indoor control means and the Since at least one of the outdoor control means is made inoperable, if this inoperable state occurs, for example, by shutting off the power supply circuit, damage to the circuit due to the occurrence of phase loss, etc. Can be avoided. For this reason, a special circuit for detecting the ripple voltage and a control unit for performing signal processing when detecting the ripple voltage are not required, which leads to increase in the number of components and complication of the configuration. It is possible to protect the circuit against a phase loss without causing a significant increase in manufacturing cost.

According to the second aspect of the present invention, a capacitor is provided between the first and second power supply wirings, and when one of the two phases supplied to the indoor control means is out of phase, the first and second Since the current flowing through the second power supply line is bypassed to the indoor control means, unnecessary power supply to the indoor control means is prevented, and the above-described operation according to the invention of claim 1 is described. Since such an inoperable state is reliably obtained, it is possible to reliably detect the phase loss.

According to the third aspect of the invention, the zero-cross point of the interphase voltage between the two phases connected to the indoor control means,
Since the phase difference determination means for determining the phase loss when the phase difference between the zero-crossing point of the interphase voltage between the two phases connected to the outdoor control means is different from the predetermined phase difference, this also prevents the occurrence of the phase loss. The determination can be made more reliably, and the reliability of the open phase determination can be improved.

According to the fourth aspect of the invention, since the phase loss determining means makes the phase loss determination when the phase difference at each zero-cross point is smaller than the predetermined phase difference, the phase loss determination operation is concrete. Therefore, the practicality can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a control circuit of an induction motor and a power supply circuit to a control unit in a first embodiment.

FIG. 2 is a diagram showing an outline of a power supply circuit to each control unit.

FIG. 3 is a diagram showing an outline of a power supply circuit according to a second embodiment.

FIG. 4 is a diagram showing voltage waveforms between phases in a normal state in which no phase loss occurs.

FIG. 5 is a diagram showing inter-phase voltage waveforms when the S phase is open.

FIG. 6 is a diagram showing a circuit configuration for phase loss determination in the third embodiment.

FIG. 7 is a diagram showing a comparison between inter-phase voltage waveforms in a normal state.

FIG. 8 is a diagram showing a comparison between inter-phase voltage waveforms when the S phase is open.

FIG. 9 is a diagram comparing and comparing inter-phase voltage waveforms when the protective device is activated.

[Explanation of symbols]

30 Outdoor control unit (outdoor control means) 43 Open phase judgment means 50 Indoor control unit (indoor control means) 60R R-phase power supply wiring 60S S-phase power supply wiring 60T T-phase power supply wiring 65 Zero-cross detection circuit (first zero-cross detection means) 66 Protective device input circuit (second zero-cross detection means) PS power supply C4 bypass capacitor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location H02P 7/63 302 H02P 7/63 302S (72) Inventor Satoshi Murai 1304 Kanaoka-cho, Sakai-shi, Osaka Daikin Industries, Ltd. Sakai Works Kanaoka Plant (72) Inventor Tomohiro Iwata 1304 Kanaoka-cho, Sakai City, Osaka Daikin Industries Ltd. Sakai Works Kanaoka Plant

Claims (4)

[Claims] 1. An indoor control means (50) for controlling an indoor unit and an outdoor control means (30) for controlling an outdoor unit supply AC currents (R, S, T) of the first to third phases. Three-phase AC power supply (P
In the air conditioner having an electric circuit connected to S) via power supply wiring (60R, 60S, 60T), the indoor control means (50) is configured to supply a first-phase alternating current (S) to the first The outdoor control means (30) is connected to the AC power supply (PS) via the power supply wiring (60S) and the second power supply wiring (60T) for feeding the second-phase AC current (T), while the outdoor control means (30) is connected to the first Connected to the AC power supply (PS) through one of the power supply wiring (60S) and the second power supply wiring (60T) and the third power supply wiring (60R) that supplies the third-phase AC current (R) An electric power supply device for an air conditioner. 2. Between the first and second power supply wirings (60S, 60T), when one of the two phases supplied to the indoor control means (50) is out of phase, the first and second The power supply device for an air conditioner according to claim 1, further comprising a capacitor (C4) for bypassing a current flowing through the power supply wiring (60S, 60T) to the indoor control means (50). 3. A first zero-cross detection means (65) for detecting a zero-cross point of the interphase voltage between the two phases connected to the indoor control means (50) and a two-phase connection for the outdoor control means (30). Second zero-cross detection means (66) for detecting the zero-cross point of the interphase voltage of
And a phase loss determination means (43) for receiving the output of each of the zero cross detection means (65, 66) and performing a phase loss determination when the phase difference of each zero cross point is different from a predetermined phase difference. The power supply device for an air conditioner according to claim 1. 4. The power supply in the air conditioner according to claim 3, wherein the phase loss determination means (43) determines the phase loss when the phase difference between the zero-cross points is smaller than a predetermined phase difference. apparatus.