JP3296695B2 - Air conditioner with inverter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To more expand the cooling ability of an air conditioner and to carefully control the ability of the conditioner even when the load largely fluctuates by providing an active converter which generates a DC voltage by using inverter power which drives an induction motor and an active element from a three- phase AC power source. SOLUTION: An active converter is constituted by generating a voltage value 17 to a smoothing electrolytic capacitor 8 connected to the output of a transistor module 7. A high-order harmonic current contained in a ripple current generated when the converter is operated is reduced when an AC rector 3 is set to a value of 2-14mH. In addition, when the effective voltage value of a three-phase AC power source 1 is set at 200V, the DC voltage generated by the active converter is boosted to about 340V. Therefore, a higher voltage can be supplied to an induction motor 12 in a compressor and the varying range of the number of revolutions of the motor 12 can be widened and, in addition, the controlling range of the ability of an air conditioner can also be widened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner and an electric power converter, and more particularly to an air conditioner with an inverter to which at least a plurality of indoor units are connected and whose cooling or heating capacity needs to be finely controlled. .

[0002]

2. Description of the Related Art Conventionally, an air conditioner with an inverter uses a capacitor input type rectifier circuit using a diode module and an electrolytic capacitor as disclosed in Japanese Patent Application Laid-Open No. 2-134314, for example. It was common to consist of
An example of obtaining a DC voltage from a three-phase power supply capable of obtaining high power by using a switching power element such as a transistor module as an active element is disclosed in
No. 59 is known.

[0003]

Generally, in order to increase the cooling capacity of an air conditioner, the power capacity of the air conditioner must be increased. It is inevitable that the generation of waves will increase. Therefore, harmonics can be reduced by adding a reactor to the rectifier circuit of the capacitor input type, but the problem of harmonics generated by electrical products and power converters is becoming a social problem as the demand for products increases. Yes, further reductions are needed in the future.

[0004] If an inverter power supply is not used, the problem of generation of harmonics is eliminated. However, when the load on the air conditioner fluctuates greatly, or in order to improve controllability, an inverter power supply is used. It is necessary to efficiently drive the induction motor built in the compressor from the capacity of the AC power supply. Furthermore, although a three-phase AC power supply is suitable as a large-capacity AC power supply, generating an inverter power supply from a three-phase AC power supply requires a DC voltage supplied to the inverter power supply from a normal single-phase AC power supply. Compared to the generation, the generation of the harmonic becomes more remarkable, including the opportunity for switching.

In the second prior art, a DC voltage as an inverter power supply is obtained by improving the power supply power factor from a three-phase AC power supply. However, generation of harmonics is not sufficiently considered. SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the related art, and to expand the cooling capacity even when the load fluctuates greatly, such as in a multi-room air conditioner to which a plurality of indoor units are connected. It is an object of the present invention to provide an air conditioner that is capable of responding to a problem and capable of performing fine-grained capacity control.

Further, the present invention solves the above-mentioned problem of the prior art, which solves the problem of harmonics generated by a power converter when handling relatively large power, and provides a low-cost power converter for the entire system. To provide.

[0007]

An air conditioner according to the present invention comprises:
Multiple indoor unit heat exchangers, outdoor unit heat exchangers, four directions
The refrigeration cycle to which the valve and the compressor are connected
In a multi-room air conditioner consisting of a stored electric motor,
A transistor module for driving the motor;
Detects the DC voltage supplied to the transistor module.
And a PWM signal to the transistor module.
Connected inverter circuit and noise connected to AC power supply
A filter and an AC rear connected to the noise filter.
The reactor is connected to the output of the AC reactor.
A flywheel diode is provided to rectify the output
Transistor module for converter and converter
Output of the transistor module for
An electrolytic capacitor for generating the DC voltage by smoothing a force.
Capacitor, the AC reactor and the converter transformer.
The AC power supply is provided between the transistor modules.
A power supply current sensor for detecting a current, and the noise filter
Isolation transformer for detecting the voltage of the AC power supply from the output of
And a PWM signal related to the current and voltage of the AC power supply.
The output to the converter transistor module
And an inverter circuit.
Current voltage is detected, and the value of the DC voltage is set to a stable voltage detection level.
Over the PWM signal, the PWM signal is
Output to the power module, and then the DC voltage value
When the voltage is lower than the foot voltage detection level, the converter circuit
The operation is stopped.

Further, in the above, the insulation transformer
The output is used as a power supply for the converter circuit.

Further, an outdoor unit control of the multi-room air conditioner.
Transmission data transmitted and received between the circuit and the inverter circuit.
Drives and stops the converter circuit
Things.

[0010] Further, an outdoor unit of the multi-room air conditioner room.
Operation stoppage between the control circuit and the inverter circuit
A stop command causes the converter circuit to be driven and stopped.
Is what you do.

Further, a transistor module for driving the induction motor, a sensor for detecting a DC voltage supplied to the transistor module, a U-phase current sensor and a V-phase sensor for detecting U-phase and V-phase currents output from the transistor module P for current sensor and transistor module
An inverter circuit that outputs a WM signal, a noise filter that is connected to a three-phase AC power supply, and is provided for each phase, and an AC reactor that is connected to each noise filter.
An output of an AC reactor is connected, a converter transistor module provided with a flywheel diode for rectifying the output, and an output of the converter transistor module is connected, and an electrolytic capacitor for generating a DC voltage by smoothing the output. An R-phase current sensor and an S-phase current sensor that are provided between the AC reactor and the converter transistor module and detect the R-phase and S-phase currents of the three-phase AC power supply; An insulation transformer for detecting the voltage of each phase of the AC power supply, and a converter circuit for outputting a PWM signal to the converter transistor module in accordance with the voltage phase of the three-phase AC power supply detected by the insulation transformer. .

In the above, the output of the insulating transformer is used as the power supply of the converter circuit. A means for detecting a DC voltage from the time when the converter circuit is turned on; a predetermined undervoltage detection level of the DC voltage; a predetermined stable voltage detection level exceeding the undervoltage detection level; Means for outputting a PWM signal to the converter transistor module when the voltage value exceeds the stable voltage detection level.

The air conditioner outdoor unit further includes an outdoor unit control circuit, and means for driving and stopping the converter circuit according to the contents of transmission data transmitted and received between the outdoor unit control circuit and the inverter circuit. ing.

Further, means for driving and stopping the converter circuit in accordance with the outdoor unit control circuit of the outdoor unit of the air conditioner, the operation stop instruction performed between the outdoor unit control circuit and the inverter circuit, and the operation stop instruction. And Further, the power conversion device according to the present invention is connected to a three-phase AC power supply, and connected to a noise filter provided for each phase, an AC reactor connected to each noise filter, and an output of the AC reactor. A converter transistor module provided with a flywheel diode for rectifying the output, an output of the converter transistor module is connected, an electrolytic capacitor for generating a DC voltage by smoothing the output, and an AC reactor and a converter transistor module. Provided in between,
An R-phase current sensor and an S-phase current sensor for detecting R-phase and S-phase currents of the three-phase AC power supply, and an insulation transformer for detecting a voltage of each phase of the three-phase AC power supply from an output of the noise filter; A converter circuit for outputting a PWM signal to the converter transistor module in accordance with the voltage phase of the three-phase AC power supply detected by the insulating transformer.

Further, the power converter is characterized in that the output of the insulating transformer is used as the power supply of the converter circuit. Further, the power conversion device, a means for detecting a DC voltage from the time when the power of the converter circuit is turned on,
A predetermined DC voltage undervoltage detection level, a predetermined stable voltage detection level exceeding the undervoltage detection level,
If the DC voltage exceeds the stable voltage detection level, PWM
Means for outputting a signal to the transistor module for converter.

[0016]

[Function] The DC voltage is detected when the power is turned on.
And the value of the DC voltage has exceeded the stable voltage detection level.
Converts the PWM signal to the transistor module for converter.
Output, and then the DC voltage value is detected as undervoltage.
When less than the level, the converter circuit stops operating
So that during normal control, the DC voltage
If the voltage is not high enough, the
It is possible and the power of the main circuit of the air conditioner is turned on.
Automatically starts operating as an active converter
Can be active converter from another circuit etc.
It is not necessary to output the operation command of the data .

As a result, even in a three-phase AC power supply in which the frequency of switching is increased and the generation of harmonics is remarkable, the generation of harmonics flowing out to the power supply is suppressed to a practical level, and further improvements will be made in the future. Can be made possible. Here, the converter refers to a portion that generates a DC voltage from an AC power supply, and the active converter refers to using an active element for the converter. Further, by generating a DC voltage by an active converter, a higher voltage can be generated as compared with a conventional capacitor input type which does not use an active element.
Therefore, the variable range of the rotation speed of the compressor can be made wider. Due to the above, the load greatly fluctuates, such as a multi-room air conditioner to which a plurality of indoor units are connected, and in the air conditioner, which will increase in capacity in the future, with the increase in capacity, It is possible to solve the contradictory condition that the generation of harmonics flowing to the power supply increases.

[0018]

[0019]

[0020]

[0021]

[0022]

Further, in the above, the output of the insulating transformer for detecting the voltage is used as the power supply of the converter circuit, so that it is not necessary to separately provide a transformer for the power supply of the converter circuit. Becomes In addition, since up to three circuits can be generated from the insulating transformer, power can be supplied to other circuits, greatly contributing to cost reduction of the entire system.

Further, a DC voltage detection sensor is provided as means for detecting a DC voltage supplied to the inverter power supply when the power supply of the converter circuit is turned on, and a DC voltage undervoltage detection level and an undervoltage detection level are provided. Is determined in advance. Then, when the value of the DC voltage exceeds the stable voltage detection level, the converter circuit outputs a PWM signal to the transistor module for converter. Specifically, a microcomputer provided in the converter circuit is used as this means.
With this, during normal control, when the DC voltage is not at a sufficiently high voltage, the operation can be stopped as a voltage shortage, and when the power of the main circuit of the air conditioner is turned on, it automatically operates as an active converter. Can be started, and it is not necessary to output the operation command of the active converter from another circuit or the like.

Further, the transmission and reception of the air conditioner outdoor unit is performed by driving and stopping the converter circuit according to the contents of the transmission and reception data between the outdoor unit control circuit and the outdoor unit control circuit and the inverter circuit. Data includes, for example, identification code, type code, length data, address, frequency command, acceleration command, operation status, capability code, model code, BCC, etc. from the outdoor unit control circuit, and identification code, type code, length data from the inverter circuit. , An address, a secondary current, a DC power, a stop factor, an operation frequency, a DC voltage detection value, a BCC, and the like, the drive and stop of the converter circuit can be optimally determined from various conditions and situations.

Further, the air conditioner includes an outdoor unit control circuit for the outdoor unit, and means for driving and stopping the converter circuit in accordance with a start and stop command performed between the outdoor unit control circuit and the inverter circuit. Accordingly, there is no need to output a signal for instructing the operation and stop of the active converter to the outdoor unit control circuit and the inverter circuit, and it is not necessary to add an extra circuit or an input / output port of a microcomputer.

The means for driving and stopping the converter circuit include data transmitted by the converter circuit between the outdoor unit control circuit and the inverter circuit, such as command frequency data, actual frequency data, and stop factor data. To automatically determine whether or not the operation as an active converter is required. Specifically, a microcomputer provided as a converter circuit is used.

[0028]

[0029]

[0030]

1 to 3 and 10 show an embodiment of the present invention.
This will be described with reference to FIG. FIG. 1 is a block diagram mainly showing a refrigeration cycle of an air conditioner with an inverter according to one embodiment of the present invention. FIG. 2 is a control block diagram showing control elements centered on the indoor unit control circuit and the outdoor unit control circuit. FIG. 3 is a block diagram showing an active converter and an inverter of an air conditioner with an inverter according to one embodiment. FIG. 10 illustrates, according to one embodiment,
This is one of the obtained results, and particularly shows the target value of the regulation and the experimental result at odd harmonics.

In FIG. 1, a refrigeration cycle 40 is connected to a plurality of indoor unit heat exchangers 38 and an outdoor unit heat exchanger 39, and changes the flow direction of the refrigerant in the refrigeration cycle 40 during cooling and heating. It is constituted by a valve 41 and a compressor 42. The compressor 42 has the induction motor 12 therein, and performs suction, compression, and discharge of the refrigerant according to the rotation speed of the induction motor 12. Further, the inverter 43 generates an inverter power supply for driving the induction motor 12 from the three-phase AC power supply 1 and controls the rotation speed of the induction motor 12 in the compressor 42.

In the control block diagram of FIG.
9 includes an indoor unit control circuit 47, the outdoor unit 50 includes an outdoor unit control circuit 35, and the indoor unit control circuit 47 includes a remote controller 44, an indoor temperature detection device 45, and an indoor unit fan motor 46. Is connected to the outdoor unit control circuit 35.
Is connected to a four-way valve 41 and an outdoor unit fan motor 48. Between the outdoor unit control circuit 35 and the inverter circuit 14, data is transmitted by a transmission line 36 for transmitting data such as an inverter operation / stop command and an inverter operation frequency command.

Hereinafter, an active converter for generating a DC voltage from an AC power supply by using an active element and an inverter power supply driven by changing the frequency of a PWM signal will be described in detail. Table 1 shows target values (IEC1000) of regulations for each order of harmonic current generated in an air conditioner that has ensured performance such as sufficient cooling capacity.
-3-2), and if the value is equal to or less than this value, it is possible to secure the performance of the air conditioner and make the generation of harmonics practical.
(Definition and measurement method are based on IEC standards.)

[0034]

[Table 1]

In FIG. 3, the transistor module 7
Is connected to a noise filter 2 provided for each phase from a three-phase AC power supply 1 via an AC reactor 3.
The converter circuit 13 performs detection 15 of the power supply voltage from the insulating transformer 4 connected to the output of the noise filter 2 and detection 16 of the power supply current from the current sensors 5 and 6 connected to the output of the AC reactor 3. A current that has the same phase as the voltage of the three-phase AC power supply 1
9 is output. That is, the voltage value 1 to the smoothing electrolytic capacitor 8 connected to the output of the transistor module 7
7 generates an active converter. Considering the load fluctuation of the multi-room air conditioner, the value of the electrolytic capacitor 8 is preferably set to 2000 to 5000 μF. Here, the higher harmonic current included in the ripple current generated by the operation of the converter is reduced by setting the AC reactor 3 to a value of 2 to 14 mH. When the effective voltage value of the three-phase AC power supply 1 is 200 V, the DC voltage generated by the active converter is boosted to about 340 V. On the other hand, in the conventional capacitor input type that does not use an active element, the voltage is about 270 V due to insertion loss and the like, and the active converter can generate a higher voltage. Therefore, the compressor 4
2, it is possible to supply a higher voltage to the induction motor 12 even with the same power supply.
The variable range of the number of revolutions of 2 can be made wider, and the capacity control range can be expanded without increasing the capacity of the compressor 42.

The compressor motor 12 is connected to the transistor module 9 using the output voltage 17 as a power supply. The inverter circuit 14 outputs the motor current 18 from the current sensors 10 and 11 connected to the output of the transistor module 9,
A voltage value 17 of the smoothing electrolytic capacitor 8 connected as a power supply of the transistor module 9 is input, and a PWM signal 20 for driving the transistor module 9 is output. Thus, an inverter is configured.

In the air conditioner having the converter and the inverter as described above, the harmonics of each order are regulated as shown in Table 1, for example, the third harmonic generated in the DC voltage. Setting the current from 2.3 A to 0.2 A may be sufficient to ensure sufficient performance such as cooling capacity and to reduce the generation of harmonics to a sufficient value.

FIG. 10 shows the order of harmonics on the horizontal axis and the target value of regulation superimposed on the three-phase AC power supply and the current value based on the experimental results on the vertical axis. The third harmonic current is less than 2.30 A and 1.6 A or more, and the fifth harmonic current is less than 1.14 A and 0.8
A, the seventh harmonic current is less than 0.77 A and 0.5 A or more, the ninth harmonic current is from 0.40 A to 0.2 A or more, and the eleventh harmonic current is 0.33 A. From 0.2A or more
The goal is to achieve 80%. As a result, without excessively reducing only the generation of harmonics and increasing the price, sufficient cooling capacity as a multi-room air conditioner, and a large characteristic unique to a multi-room air conditioner such as a change in the number of operating units. Can respond to load fluctuations.

Further, the odd-numbered n-th harmonic current of at least 15 and not more than 39 and superimposed on the three-phase AC power supply is less than (0.15 × 15 / n) A and (0.12 × 15
/ N) The even-numbered m-th harmonic current of not less than A and not less than 8 and not more than 40 and less than (0.23 × 8 / m) A and (0.13
8 × 8 / n) A or more so as to achieve approximately 70 to 80% of the target value of regulation,
It is possible to prevent interference with OA equipment such as a personal computer and a word processor through a power supply, and to secure a cooling capacity as a multi-room air conditioner and a performance capable of coping with a specific load change.

Here, reducing the generation of higher harmonics excessively only complicates the configuration of the converter and the inverter. Next, FIG.
In the block diagram showing the active converter and the inverter, the details of the output portion of the insulating transformer 4 for detecting the voltage will be described with reference to the block diagram of FIG.

In the above active converter, it is necessary to detect the voltage of the three-phase AC power supply 1. Therefore, the insulation transformer 4 is provided with R, S,
The voltage of each T phase is input, and the voltage reduced for each phase is output in three phases. In addition, the R-phase 28, the S-phase 29, and the T-phase 30 (or two of the three phases may be separately extracted) are separately extracted from the three-phase outputs as shown in FIG. .

Further, a power supply 1 (25), a power supply 2 (26), and a power supply 3 (27), which are voltage outputs serving as circuit power supplies,
As shown in the figure, they are taken out in parallel via a diode module 21, an electrolytic capacitor 22, a regulator 23, and a capacitor 24.

As a result, the power supply voltage can be detected and the power supply of the circuit can be made up to a maximum of three circuits with one transformer 4.
By using one of these outputs as the power supply of the converter circuit, it is not necessary to separately provide a transformer for the power supply of the converter circuit, which is advantageous in cost. Also,
Power can be supplied to other circuits, and the overall system can be reduced in cost.

Next, the start of the operation of the active converter and the stop of the operation due to the shortage of the generated DC voltage will be described with reference to the voltage waveform diagram of FIG. 5 and the flowchart of FIG. In FIG. 5, the horizontal axis represents the time from when the main circuit power supply of the air conditioner is turned on, and the vertical axis represents the DC voltage generated in the electrolytic capacitor 8 at that time.

When the power of the main circuit of the air conditioner is turned on, the DC voltage applied to the electrolytic capacitor 8 has a voltage waveform 31 as shown in FIG. This voltage waveform 31
When the power of the converter circuit 13 is turned on, it is detected by the DC voltage detection sensor 17 supplied to the inverter transistor module.

At the time of normal control, the microcomputer provided in the converter circuit determines an undervoltage detection level in advance as shown in the flowchart of FIG. 6, and operates when the DC voltage is not at a sufficiently high voltage, as an undervoltage. To stop. However, if the converter circuit is operated as an active converter when the power is turned on as it is, the time required for resetting the microcomputer is extremely longer than the time required for the DC voltage to reach a voltage higher than the undervoltage detection level 32. Since it is short, converter circuit 13 stops the operation of the active converter on the assumption that the DC voltage is lower than the undervoltage. Therefore, starting at the time of power-on cannot be performed in this state.

Therefore, a stable voltage detection level 33 which further exceeds the undervoltage detection level is predetermined, and the converter circuit 13 sends the PWM signal to the converter transistor module 9 when the DC voltage value exceeds the stable voltage detection level 33. Output. Thus, by automatically starting the operation, there is no need to provide a means for separately sending an operation start signal to the active converter, and the circuit for sending the signal is not required. As described above, during normal control, when the DC voltage is not at a sufficiently high voltage, the operation can be stopped as a voltage shortage, and when the power of the main circuit of the air conditioner is turned on, the operation as an active converter is automatically performed. Can be started.

Next, the automatic driving and stopping of the converter circuit will be described with reference to FIGS. FIG. 7 shows a converter circuit, an inverter circuit,
FIG. 8 is a block diagram showing signal transmission of the outdoor control circuit.
FIG. 9 is a block diagram showing details of signals transmitted and received between the inverter circuit and the outdoor control circuit, and FIG. 9 is a flow chart.

In the air conditioner with an inverter, the outdoor control circuit 35 and the inverter circuit 14 are used to control the refrigeration cycle 40 as described above. The transmission data 51 (identification code, type code, length data, address, etc.) of the outdoor unit control circuit shown in FIG. 8 for transmitting data such as an inverter operation / stop command and an inverter operation frequency command between the two circuits. , Frequency command, acceleration command, driving situation, capability code, model code, BCC),
Transmission data 52 (identification code, type code, length data, address, secondary current, DC power, stop factor, operation frequency, Vdc detection value, BCC) of the inverter circuit are transmitted and received on the transmission line 36.

The converter circuit 13 monitors the transmission data 51 and 52 on the transmission line 37 as follows. FIG.
First, it is determined whether the frequency command data in the transmission data 51, 52 is 0. If it is not 0, the operation is continued. Similarly, it becomes as follows.

(1) If the actual frequency data is not 0, the operation is continued, and if it is 0, the process proceeds to the next step.

(2) Depending on the presence or absence of the stop cause code, if there is no stop cause code, the operation is continued, and if there is, the drive of the active converter is stopped.

As described above, the converter circuit 13 determines whether or not the active converter does not need to be driven.
, The active converter can be automatically stopped. Then, the outdoor control circuit 35 and the inverter circuit 14 do not need to separately send a stop command signal to the converter circuit 13, and a circuit for sending the signal is not required.

[0054]

According to the present invention, even when the load fluctuates greatly, such as in a multi-room air conditioner to which a plurality of indoor units are connected, the generation of harmonics, which are becoming a social problem, can be reduced. It is possible to provide an air conditioner with an inverter which can be reduced, can cope with an increase in cooling capacity, and can perform fine capacity control.

[Brief description of the drawings]

FIG. 1 is a block diagram mainly showing a refrigeration cycle of an air conditioner with an inverter according to an embodiment of the air conditioner with an inverter of the present invention.

FIG. 2 is a control block diagram showing control elements centering on an indoor unit control circuit and an outdoor unit control circuit according to one embodiment.

FIG. 3 is a block diagram showing an active converter and an inverter.

FIG. 4 is a detailed block diagram of an output portion of an isolation transformer for detecting a voltage.

FIG. 5 is a waveform diagram of a DC voltage generated from the start of operation of the active converter.

FIG. 6 is a flowchart illustrating an operation stop due to a shortage of a generated DC voltage.

FIG. 7 is a block diagram showing signal transmission of a converter circuit, an inverter circuit, and an outdoor control circuit.

FIG. 8 is a block diagram showing details of signals transmitted and received between the inverter circuit and the outdoor control circuit.

FIG. 9 is a flowchart for explaining automatically driving and stopping the converter circuit.

FIG. 10 is a graph showing a target value for regulating the generation of harmonics and an experimental result according to one embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Three-phase AC power supply, 2 ... Noise filter, 3 ... AC reactor, 4 ... Insulation transformer, 5 ... R-phase current sensor, 6 ...
S phase current sensor, 7: transistor module for converter, 8: electrolytic capacitor, 9: transistor module for inverter, 10: U phase current sensor, 11: V phase current sensor, 12: induction motor, 13: converter circuit,
14 ... Inverter circuit, 15 ... Power supply voltage detection, 16 ... Power supply current detection, 17 ... Output voltage, 18 ... Motor current, 19
... Converter PWM signal, 20 ... PWM signal, 21 ... Diode module, 22 ... Electrolytic capacitor, 23 ... Regulator, 24 ... Capacitor, 25 ... Power supply 1, 26 ...
Power supply 2, 27: Power supply 3, 28: R-phase voltage, 29: S-phase voltage, 30: T-phase voltage, 31: Voltage waveform, 32: Undervoltage detection level, 33: Stable voltage detection level, 34: Converter operation start Time, 35 ... outdoor unit control circuit, 36, 37
.. Transmission line, 38 indoor heat exchanger, 39 outdoor heat exchanger, 40 refrigeration cycle, 41 four-way valve, 42 compressor, 43 inverter, 44 remote controller,
45: indoor temperature detecting device, 46: indoor unit fan motor, 47: indoor unit control circuit, 48: outdoor unit fan motor, 49: indoor unit, 50: outdoor unit, 51: transmission data of the outdoor unit control circuit, 52 ... Transmission data of the inverter circuit.

Continuation of the front page (51) Int.Cl. ⁷ Identification code FI F25B 1/00 371 F25B 1/00 371N H02P 7/63 302 H02P 7/63 302R (72) Inventor Makoto Ito 390 Muramatsu, Shimizu, Shizuoka Prefecture Shares (56) References JP-A-7-167480 (JP, A) JP-A-7-213067 (JP, A) JP-A-7-123722 (JP, A) JP-A-6 −141559 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02M 7/48 F24F 11/02 F25B 1/00 H02P 7/63

Claims (4)

(57) [Claims] 1. A multi-room air conditioner comprising a refrigeration cycle to which a plurality of indoor unit heat exchangers, an outdoor unit heat exchanger, a four-way valve, and a compressor are connected, and a motor built in the compressor. A transistor module for driving the electric motor; a sensor for detecting a DC voltage supplied to the transistor module; an inverter circuit for outputting a PWM signal to the transistor module; a noise filter connected to an AC power supply ; An AC reactor connected to a noise filter , an output of the AC reactor is connected, a converter transistor module provided with a flywheel diode for rectifying the output, an output of the converter transistor module is connected, Electrolytic capacitor that generates the DC voltage by smoothing Inspection and capacitors provided between the AC reactor and of the converter transistor module, a power supply current sensor for detecting a current of the alternating current power supply, the voltage of the AC power from the output of the noise filter
And a PWM signal related to the current and voltage of the AC power supply.
Converter to output to transistor module for converter
A DC circuit for detecting the DC voltage when power is turned on.
If the value of the flowing voltage exceeds the stable voltage detection level, the PWM signal
Output to the transistor module for converter
After that, the value of the DC voltage exceeds the undervoltage detection level.
An air conditioner with an inverter, wherein the converter circuit stops operating when the amount is small . 2. The method of claim 1 wherein said insulating
An air conditioner with an inverter , wherein an output of a transformer is used as a power supply of the converter circuit . 3. The multi-chamber according to claim 1, wherein
The outdoor unit control circuit of the air conditioner and the inverter circuit;
Depending on the transmission data being sent and received between
An air conditioner with an inverter, which drives and stops a road . 4. The multi-chamber according to claim 1, wherein
An outdoor unit control circuit of the air conditioner room and the inverter circuit;
The conversion instruction is executed between
An air conditioner with an inverter, wherein the air conditioner drives and stops the inverter circuit .