JP3176587B2 - Air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner using a compressor driven at a variable speed by an inverter.
In particular, the present invention relates to an air conditioner that combines a motor drive device and a refrigeration cycle that shortens the time required to reach a set temperature after starting a heating operation, or that enables comfortable heating in a cold region.

[0002]

2. Description of the Related Art In order to reduce annual power consumption, a conventional air conditioner has been designed to improve its performance in a low rotational speed range of a compressor which does not require a relatively large capacity. As a recent technology for improving such performance, there is a technology that variably controls the number of revolutions of a motor for driving a compressor using a PWM (Pulse Width Modulation) control inverter. The rotational speed control in the PWM control is intended to increase the efficiency without increasing the driving torque so much.

Further, there is an air conditioner which uses a compressor having a large refrigerant compression capacity corresponding to an operation load and which is used when the outside air temperature is relatively low or when the heating operation load is large.

When the outdoor air temperature is low or the required heating capacity is large, the refrigerant discharge pressure of the compressor increases and the condensing pressure of the indoor heat exchanger also increases. In order to reduce the condensing pressure, the condensing pressure is reduced by increasing the heat transfer area of the indoor heat exchanger to facilitate condensation of the refrigerant gas, thereby reducing the driving torque of the electric motor and increasing the efficiency. It is possible.

As a conventional technique for controlling the number of revolutions of a motor so as to increase the efficiency, for example, a motor driving device using a high power factor power converter for suppressing harmonics of an input current as a power source is disclosed in -89743.

FIG. 10 is a block diagram showing such a conventional motor driving device, wherein 1 is an AC power supply, 2 is a rectifier, 2
a, 2b, 2c, 2d are diodes, 3 is a reactor,
4 is a diode, 5 is a capacitor, 6 is a switch element,
7 is a voltage comparator, 8 is a multiplier, 9 is a load current detector, 1
0 is a current comparator, 11 is an oscillator, 12 is a drive circuit, 13
Denotes an inverter, 14 denotes an electric motor, 15 denotes a microcomputer, 16 denotes an inverter drive circuit, and 17 denotes a modulator.

In the figure, a rectifier 2, a reactor 3,
Diode 4, capacitor 5, switch element 6, voltage comparator 7, multiplier 8, load current detector 9, current comparator 1
0, an oscillator 11, a drive circuit 12, and a modulator 17 constitute a power converter, and the inverter 13 uses the power converter as a power source.

First, the power converter will be described.

The AC power supply voltage from the AC power supply 1 is full-wave rectified by a rectifier 2 composed of diodes 2a to 2d and converted into a rectified voltage Es. This rectified voltage Es is applied to the capacitor 5 via the reactor 3 and the diode 4, and a smoothed DC voltage Ed is obtained. These diodes 4
A switch element 6 is provided in parallel with the capacitor 5.

The DC voltage Ed smoothed by the capacitor 5 is divided by the resistors R3 and R4 to form a DC voltage Ed ', and a deviation value between the DC voltage Ed' and the reference voltage Eo is obtained by the voltage comparator 7 to control the voltage. A signal Ve is created.

A rectified voltage Es obtained by full-wave rectification of the sine-wave AC power supply voltage by the rectifier 2 has resistances R1, R
2, a sine wave synchronization signal Es' is obtained, and the sine wave synchronization signal Es' and the voltage control signal Ve from the voltage comparator 7 are operated by the multiplier 8 to form the current reference signal Vi '. Is done. This current reference signal Vi ′ is supplied to the load current detector 9.
Is compared with the current signal Vi obtained by
A modulated signal Vk is obtained. This modulation signal Vk is applied to the modulator 1
7 modulates the sawtooth or triangular carrier wave Vk ′ from the oscillator 11 and changes the duty ratio according to the modulation signal Vk.
g is created. The drive circuit 12 drives the switch element 6 on and off by the switching drive signal Vg.

As described above, in this conventional example, the switching element 6 is turned on and off while following the waveform of the sine-wave rectified voltage Es, whereby the input AC current i is reduced at a high power factor. A sinusoidal current with few harmonics can be obtained, and the conduction ratio of the switch element 6 is changed according to the deviation value between the reference voltage Eo and the DC voltage Ed. Regardless, a stable DC voltage Ed is obtained. Therefore, it is described that by appropriately setting the reference voltage Eo and the resistance values of the resistors R3 and R4, the DC voltage Ed can be set to a desired voltage value, and the input AC power can be converted to a DC output. I have.

Next, the motor drive circuit in FIG. 10 will be described.

The DC power generated by the power converter is inversely converted into AC power by the inverter 13 and supplied to the electric motor 14 to drive it. In addition, a PWM signal calculated and output from the microcomputer 15 based on the speed command is supplied to the inverter 13 via the inverter driving circuit 16, whereby the inverter 13 is driven, and its switching element (not shown) is driven. On / off operation is performed at a predetermined duty ratio.

Next, as a conventional air conditioner in which the heat transfer area of the indoor heat exchanger is increased, for example, a conventional energy-saving air conditioner GD series employing a new dehumidifying method: Toshiba Review, Vol. 51, No. 2 , 1996 pp. 67-70] (hereinafter referred to as Document 1), recently, the indoor heat exchanger is provided from the front to the rear of the indoor unit, and furthermore, the indoor heat exchanger is further provided during the heating operation. An air conditioner provided with an indoor auxiliary heat exchanger used as a subcooler downstream of the heat exchanger has been developed.

[0016]

The above prior arts have the following problems.

1) When the operation load is large, particularly when the heating operation is performed in a region where the outdoor temperature is extremely low such as -10 ° C. or -15 ° C. in a cold region, etc. In a case where the driving speed is extremely low and the walls and furniture are completely cooled, the above-described PWM control does not increase the driving torque so much to increase the efficiency. It could not be rotated up to several times, could not reach the set room temperature, or required a long time.

2) When a compressor having a large refrigerant compression capacity corresponding to the operation load is used, when the outside air temperature is relatively high and the heating operation load is small, the operation capacity is excessive and the compressor is intermittent. Resulting in. In the case of this intermittent operation, the power consumption is increased, and the room temperature rises and falls, so that the comfort is impaired.

3) In a home air conditioner, an upper limit is set for the input current of the air conditioner in consideration of the average breaker capacity. For these reasons, the driving torque cannot be increased so much.

4) When the outdoor air temperature is low, the required heating capacity is large, so that the refrigerant discharge pressure of the compressor increases and the condensing pressure of the indoor heat exchanger also increases. If the condensing pressure is high, the compression work of the compressor increases, which leads to an increase in power consumption.

5) In order to reduce the power consumption, it is necessary to reduce the condensation pressure. To this end, it is conceivable to increase the heat transfer area of the indoor heat exchanger so that the refrigerant gas is easily condensed. However, since the dimensions of the standard air conditioner, which takes into account the ease of installation and the size of the room, are fixed, the heat transfer area of the indoor heat exchanger is directly related to the size of the air conditioner. It was difficult to enlarge.

As described above, in the indoor unit, the indoor heat exchanger is made sufficiently large, and further, even in the case of an air conditioner provided with an indoor auxiliary heat exchanger, the piping configuration of the indoor heat exchanger and It is necessary to improve the heat transfer performance in the indoor heat exchanger as much as possible and maintain the performance of the refrigeration cycle sufficiently high in each of the cooling and heating operations by devising the relationship with the air flow.

More specifically, in the above-described conventional motor driving device, the DC voltage Ed can be obtained stably even when the input AC power supply voltage changes, If it is desired to change the DC voltage Ed accordingly, it is necessary to correct the circuit constant. In particular, in the above-described conventional example, since the power converter is of the boosting type, in order to perform stable control, the input AC power supply voltage is set to 100 V according to the following equation: DC voltage Ed ≧ AC power supply voltage × 1.41 + 10 [V]. In the case of, a DC voltage Ed of 150 V or more
When the input AC power supply voltage is 200 V, 3
The DC voltage Ed is set to 00 V or more.

Therefore, if the AC power supply 1
If you want a power converter that can be used with either
The set value of the DC voltage Ed needs to be 300 V or more.

For example, when the input AC power supply voltage is 100 V, the DC voltage Ed is set to a constant voltage of about 300 V,
It is conceivable that the loss can be reduced by controlling the inverter 13 at an arbitrary DC voltage Ed of 150 V or more without a chopper having a 100% duty ratio, rather than performing the rotation speed control by driving the inverter 13 with a chopper at an arbitrary duty ratio. In the above conventional example,
Since this point is not taken into account, there is a problem that the loss is increased more than necessary.

In the above conventional example, a sine-wave rectified voltage Es obtained by full-wave rectification of an AC power supply voltage from the AC power supply 1 is divided by resistors R1 and R2 to obtain a sine-wave synchronous signal Es'.
And a voltage control signal Ve is calculated by the multiplier 8 to generate a current reference signal Vi ′.
Since the input AC current is controlled in the form of a sine wave with reference to i ′, the rectified voltage Es is different when the AC power supply voltage is 100 V and 200 V, and the shape and value of the sine wave are significantly different between the two. . Therefore, the AC power supply voltage is set to 10
When shared between 0 V and 200 V, the power converter has a low power factor and a high harmonic content.

In the motor drive device and the air conditioner using the above-described power converter, when using 100V and 200V as the AC power supply voltage, the power converter must have specifications corresponding to the respective specifications. Therefore, problems such as an increase in the number of models and a decrease in production efficiency occur.

Further, when the input AC current is small, and especially when the above control is not necessary, it is considered to eliminate the unstable operation, loss, noise and the like of the control at the time of low input current. Absent.

For example, when a resistor is used as the load current detector 9 and a current signal Vi is to be obtained from a voltage generated at both ends, even for a very small current, control is required.
It is necessary to generate a sufficient voltage, and specifically, it is necessary to set a large resistance value of this resistor. In this case, when the load current increases, the power consumed by the resistor increases, resulting in an increase in loss.

Further, in the inverter 13, the DC power supply voltage Ed is kept constant, and the DC power supply voltage Ed is chopped at a duty ratio corresponding to the duty ratio of the PWM signal from the microcomputer 15, so that the DC power supply voltage Ed is changed according to the duty ratio. The electric motor 14 rotates at the predetermined rotation speed. By changing the duty ratio, the number of revolutions of the motor 14 changes. In such a conventional motor drive device, however, the inverter 1 always operates as described above.
3 is driven by a chopper, which causes a power loss (chopper loss), which inevitably lowers the efficiency.

An object of the present invention is to provide an air conditioner in which the power loss in the inverter can be reduced and the condensing pressure in the indoor heat exchanger can be reduced to improve the efficiency. And an air conditioner provided with a motor drive device that reduces power loss in an inverter.

[0032]

In order to achieve the above object, the present invention provides a compressor for refrigerant compression, a four-way valve for switching between a cooling and heating operation state, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger. A refrigeration cycle connected in a ring by a connection pipe; and a compressor motor drive device for driving the compressor motor. The compressor motor drive device rectifies and smoothes an input AC voltage to output DC voltage. A power converter that generates a voltage and variably controls the output DC voltage, and an inverter that variably drives the rotation speed of the compressor motor using the output DC voltage of the power converter as a power supply voltage. , The power converter
Makes its output DC voltage variable, and the indoor heat exchanger is closer to the windward side than the indoor heat exchanger and the indoor heat exchanger.
Used for supercooling during heating operation arranged on the side of the indoor air intake
An auxiliary heat exchanger, and when the outdoor temperature is low, during heating operation, the output DC voltage of the power converter is increased to operate the compressor motor at a high rotational speed, but the current is lower than the limit current. It is configured to have a size having a refrigerant condensing amount that maintains the operating current.

According to such a configuration, a power converter that rectifies and smoothes an input AC voltage to generate an output DC voltage and variably controls the output DC voltage, and converts the output DC voltage of the power converter into a power supply voltage Since the compressor motor driving device includes an inverter for variably driving the rotation speed of the compressor motor, the cooling and heating operation can be performed by changing the rotation speed of the compressor motor.

Further, even in a heating operation in which the outdoor temperature is low, even if the output DC voltage is increased and the compressor motor is operated at a high rotational speed, a refrigerant having a refrigerant condensing amount that maintains an operating current lower than the limited current. Since the internal heat exchanger is provided, even if the compressor motor having a low outdoor temperature is operated at a high rotation speed for a long time, the operating current does not reach the limit current value.

Further, the indoor heat exchanger is supercooled during the heating operation.
Since an auxiliary heat exchanger is provided for cooling, sufficient supercooling can be obtained at the outlet of the indoor heat exchanger serving as a condenser during heating operation, and the work of the compressor can be reduced. The performance is improved and power saving can be achieved.

Further, according to the present invention, the indoor heat exchanger comprises:
When the outdoor temperature is -10 ° C or -15 ° C during heating operation,
Even when the compressor motor is operated at the maximum rotational speed by maximizing the output DC voltage of the power converter, the compressor is configured to have a refrigerant condensing amount that maintains an operation current lower than the limited current.

With this configuration, even if the compressor motor is operated at the maximum rotational speed for a long time in a low temperature environment where the outdoor temperature is -10 ° C. or lower or -15 ° C. or lower, the heating is performed with the operating current lower than the limited current. Driving can be performed.

Further, the present invention provides the indoor heat exchanger, wherein the subcooling auxiliary heat exchanger is arranged on the indoor air suction port side which is on the windward side of the indoor heat exchanger. .

[0039] With this configuration, during the heating operation, the subcooling auxiliary heat exchanger can exchange heat with the relatively low-temperature indoor air flow before exchanging heat with the indoor exchanger, and becomes a condenser. Sufficient supercooling is obtained at the outlet of the indoor heat exchanger, and the work of the compressor can be reduced.In addition, the indoor air flow that has exchanged heat with the auxiliary heat exchanger exchanges heat with the indoor heat exchanger on the high temperature side. As a result, the heating performance is further improved, and significant power saving can be achieved.

Further, in the present invention, in the indoor heat exchanger, the subcooling auxiliary heat exchanger may be provided at a side of a room air suction port on the windward side of the indoor heat exchanger and in a refrigerant passage. It is arranged on the downstream side of the indoor heat exchanger to have a small flow passage area.

With this configuration, during the heating operation, the subcooling auxiliary heat exchanger can exchange heat with the relatively low-temperature indoor air flow before exchanging heat with the indoor exchanger and reduce the flow rate of the refrigerant. The heat transfer rate can be increased to make the heat transfer rate sufficiently high, and sufficient supercooling can be obtained at the outlet of the indoor heat exchanger, which is the condenser, so that the work of the compressor can be reduced, and heat exchange with the auxiliary heat exchanger can be achieved. The heated indoor air flow exchanges heat with the indoor heat exchanger on the high temperature side and is heated to a higher temperature, so that the heating performance is further improved and power saving is further promoted.

[0042]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the air conditioner according to the present invention.
18 is a block diagram showing an embodiment of the present invention, wherein 18 is a DC voltage switch, 19 is a trigger element, 20 is a synchronous signal switch, 21 is a voltage command switch, 22 is a drive signal switch, and 23 is an input current detector. , 24 are active converter blocks, and 25 is an LPF (low-pass filter). The same reference numerals are given to portions corresponding to those in FIG.

In FIG. 1, a DC voltage Ed obtained by smoothing with a capacitor 5 is divided by a voltage dividing circuit composed of resistors R4, R5 and R6 to form DC voltages Ed1 and Ed2. Here, Ed1 = Ed × (R5 + R6) / (R4 + R5 + R6) Ed2 = Ed × R6 / (R4 + R5 + R6), and Ed1> Ed2.

The DC voltage Ed1 is a DC voltage switch 1
The DC voltage Ed2 is supplied to the contact A of the changeover switch 8 at the contact B of No. 8 respectively. This DC voltage switch 18
Is the divided voltage Ed of the DC voltage Ed by the microcomputer 15
1 in accordance with the DC voltage changeover switch 1
8 outputs the selected one of the DC voltages Ed1 and Ed2 as the DC voltage Ed1 '.

The output DC voltage Ed1 'of the DC voltage switch 18 is supplied to the contact B of the voltage command switch 21. The contact point A of the voltage command changeover switch 21 is supplied with a DC voltage Ed2 'formed by smoothing a PWM signal output from the microcomputer 15 for speed control of the electric motor 14 by the LPF 25. This voltage command changeover switch 21 is also switched by the microcomputer 15 and is controlled.
When the motor load is smaller than 100%,
The contact B side has a large motor load and a duty ratio of 10
When it is 0%, the contact A side is selected respectively.

One of the DC voltages Ed1 'and Ed2' selected by the voltage command switch 21 is the DC voltage E1.
The voltage control signal Ve is supplied to the voltage comparator 7 as d ', and a deviation value from the reference voltage Eo is obtained to form a voltage control signal Ve.

In the conventional example shown in FIG. 10, this voltage control signal Ve is obtained by dividing one type of DC voltage Ed ′ obtained by dividing the DC voltage Ed smoothed by the capacitor 5 into the reference voltage E.
In the first embodiment, either one of two types of DC voltages Ed1 and Ed2 obtained by dividing the DC voltage Ed and the DC voltage Ed2 ′ obtained from the LPF 25 is obtained. Is the DC voltage Ed ′ described above, and is compared with the reference voltage Eo.

On the other hand, the rectified voltage Es of the sine wave full-wave rectified waveform output from the rectifier 2 is divided by a voltage dividing circuit composed of resistors R1, R2 and R3 to form voltages Es1 and Es2. Here, Es1 = Es × (R2 + R3) / (R1 + R2 + R3) Es2 = Ed × R3 / (R1 + R2 + R3), and Es1> Es2.

The voltage Es1 is supplied to the contact B of the synchronous signal changeover switch 20, and the voltage Es2 is supplied to the contact A of the synchronous signal changeover switch 20. The synchronization signal changeover switch 20 is also switched by the microcomputer 15 in accordance with the divided voltage Ed1 of the DC voltage Ed smoothed by the capacitor 5, similarly to the DC voltage changeover switch 18, and the output from the synchronization signal changeover switch 20 is controlled. The applied voltage Es1 or Es2 is supplied to the multiplier 8 as a sine wave synchronization signal Es ′.

The current reference signal Vi 'is obtained from the multiplier 8, and the ON / OFF control of the switch element 6 is performed using the current reference signal Vi' in the same manner as in the conventional example shown in FIG.

As described above, also in the first embodiment, the switch element 6 is turned on and off while following the rectified voltage Es of the sine wave full-wave rectified waveform. A sinusoidal input AC current with a high power factor and few harmonics can be obtained, and the reference voltage Eo
Since the conduction ratio of the switching element 6 is changed in accordance with the deviation value between the DC voltage Ed 'and the DC voltage Ed', a stable DC voltage Ed can be obtained regardless of the load fluctuation. Therefore, the DC voltage Ed can be set to a desired voltage value by appropriately setting the reference voltage Eo and the resistance values of the resistors R4, R5, and R6.

Here, the microcomputer 15 detects the input AC current Is by the input current detector 23.
A trigger signal VT of “L” (low level) is supplied to the trigger element 19 until the current value of the input AC current Is becomes a predetermined value or more. The trigger element 19 controls the drive circuit 12 during the “L” period of the trigger signal VT to turn off the switch element 6. When the trigger signal VT changes from "L" to "H" (high level), the trigger element 19 causes the switch element 6 to operate at this point.

The PWM output from the microcomputer 15
The signal is supplied to an inverter drive circuit 16 via a drive signal switching switch 22 which is normally closed on the setting A side. The inverter drive circuit 16 controls the inverter 13 at a duty ratio corresponding to the duty ratio of the PWM signal. ON / OFF control of the switch elements not to be performed. This allows
In the inverter 13, the DC power of the DC voltage Ed supplied from the capacitor 5 is chopped at this duty ratio and converted into AC power, supplied to the electric motor 14 and rotated at a rotational speed according to the duty ratio of the PWM signal.

Next, a control operation method according to the first embodiment will be described with reference to FIG. 2, taking a domestic case as an example. In the case of Japan, there are two types of AC power supply voltage, 100V and 200V.

First, when the power is turned on (step 10)
0), the microcomputer 15 is set to the initial state, whereby the microcomputer 15 sets the DC voltage changeover switch 18, the synchronization signal changeover switch 20 and the voltage command changeover switch 21 to the contact B side, and sets the drive signal changeover switch 22 to the contact A Close to each side. As a result, the DC voltage switch 18
Selects the DC voltage Ed1, and the voltage comparator 7 is supplied with the following DC voltage Ed ′, Ed ′ = Ed × (R5 + R6) / (R4 + R5 + R6). In the synchronization signal changeover switch 20,
The sine wave synchronization signal Es1 is selected.

In this state, the charging operation is started by the capacitor 5, and the microcomputer 15 detects the divided voltage Ed1 of the DC voltage Ed of the capacitor 5 (Step 101). From the voltage value of the detected DC voltage Ed1, from the voltage value of Ed = Ed1 × (R4 + R5 + R6) / (R5 + R6), if the DC voltage Ed is higher than 160 V, for example (step 102), the input AC power supply voltage is 200V
Is determined, the DC voltage switch 18 is switched to the contact A (step 103). As a result, the DC voltage Ed ′ becomes the DC voltage Ed2, and the DC voltage Ed obtained in the capacitor 5 becomes Ed = Ed2 × {1+ (R5 + R4) / R6}.

The synchronization signal changeover switch 20 is set to the contact A
(Step 104). Therefore, the sine wave synchronization signal Es 'at this time is as follows: Es' = Es × R3 / (R1 + R2 + R3).

On the other hand, when the DC voltage Ed is, for example, 120 V
If it is lower than (Step 102), it is determined that the input AC power supply voltage is 100 V, and the DC voltage switch 18
Remain closed to the contact B side (step 11).
0). Therefore, the DC voltage Ed of the capacitor 5 is given by Ed = Ed1 × {1 + R4 / (R5 + R6)}.

When the synchronization signal changeover switch 20 is set to the contact B
(Step 111). Therefore, the sine wave synchronization signal Es 'at this time is as follows: Es' = Es × (R2 + R3) / (R1 + R2 + R3)

As described above, by controlling the switching of the DC voltage switch 18 and the synchronizing signal switch 20 in accordance with the magnitude of the input AC power supply voltage, when the input AC power supply voltage is 200 V, the DC voltage Ed 'and the sine The wave synchronizing signal Es' is a lower DC voltage Ed2, Es2, respectively,
When the input AC power supply voltage is 100 V, the DC voltage E
d 'and the sine-wave synchronization signal Es'
d1 and Es1.

Thus, the input AC power supply voltage is 100 V
And the difference of the DC voltage Ed 'between 200 V and 200 V can be suppressed, the control becomes unstable due to the amplitude of the voltage control signal Ve becoming too large and saturated, and the sine wave synchronization signal Es' Further, it is possible to prevent a problem that the current reference signal Vi ′ calculated from the voltage control signal Ve is disturbed and the current waveform is not a sine wave.

In this embodiment, the input AC power supply voltage is of two types, 100 V and 200 V. However, in general, the input AC power supply voltage is of n types of V1, V2,..., Vn, and the DC voltage Ed is Similarly, “Es” is also set to n types, and it is determined whether the input AC power supply voltage is V1, V2,..., Vn, and according to the determination result, the DC voltage corresponding to the input AC power supply voltage is determined. The same effect can be obtained by setting Ed 'and Es'.

In step 102, when the input AC power supply voltage is 20
When it is determined that the voltage is 0 V, the voltage command changeover switch 21 is kept closed to the contact B side (step 105). At this time, it is almost E0 = Ed ′, and therefore, the DC voltage Ed is as follows: Ed = E0 × {1+ (R5 + R4) / R6}. In this case, for example, Ed = 300V.

At this time, the drive signal switching switch 22 is kept closed to the contact A (step 105), and the PWM signal output from the microcomputer 15 is driven by the inverter via the drive signal switching switch 22. It is supplied to the circuit 16.

By the above operation, the DC power Ed generated by the power converter is inversely converted into AC by the inverter 13,
As a result, the electric motor 14 is driven (step 10).
6). The microcomputer 15 generates and outputs the above-mentioned PWM signal by an operation based on the speed command, similarly to the conventional example shown in FIG.
The inverter 13 is driven via the
The switching element 3 is turned on and off at a predetermined duty ratio according to the duty ratio of the PWM signal to control the rotation speed of the electric motor 14.

Generally, when the AC power supply voltage is above V
1, V2,..., Vn, any of Vj (j = 1, 2,.
, N), the DC voltage Ed ′ corresponding to the input AC power supply voltage Vj is compared with a constant reference voltage Eo, and the DC voltage Ed obtained by rectifying and smoothing the input AC power supply voltage Vj is calculated. An arbitrary constant value (for example, 300 V) is set, and the switch element of the inverter 13 is turned on and off at an arbitrary duty ratio.

In the booster circuit, when this DC voltage Ed is reduced to a value equal to or lower than the full-wave rectified voltage Es of the input AC power supply voltage, the power factor is reduced and the input current waveform is disturbed. To avoid this problem, if it is determined that the voltage is 200 V, Ed = 3
Control is performed with 00V constant. Of course, Ed = 300V
It is a condition that the desired rotation speed of the electric motor 14 can be obtained. Even if the voltage is increased to 300 V or more, the gist of the present invention is not impaired.

The microcomputer 15 detects the input AC current Is by the input current detector 23 (step 107), and outputs an "H" trigger signal VT to the trigger element 19 during a period when the input AC current Is is large. The operation is continued (step 109) so that the switch element 6 is turned on and off during the period (step 108).

Even if it is determined in step 102 that the input AC power supply voltage is 100 V, the voltage command changeover switch 21 is kept closed to the contact B (step 112). Therefore, similar to the above, almost E0 = E
d ′, and the DC voltage Ed becomes Ed = E0 × {1 + R4 / (R5 + R6)}. In this case, for example, Ed = 150V. In this way, the capacitor 5 is shared while sharing the reference voltage E0.
Can be set to a voltage value different from that when the input AC power supply voltage is 200 V.

At this time, the duty ratio of the inverter 13 is 10
If it is less than 0% (step 116), step 10
In the same manner as in steps 5 and 106, the motor 14 is driven (steps 112 and 113).
Similarly, the switch element 6 is turned on and off (steps 114 and 115), and the operation is continued as it is (step 118).

However, during operation at an input AC power supply voltage of 100 V, for example, the motor load increases and the inverter 1
If the duty ratio of the switch element in step 3 becomes 100% (step 116), the voltage command changeover switch 21 is set to the contact A side, and the drive signal changeover switch 22 is set to the contact B.
Side (step 117).

As a result, the switch element drive signal (PWM signal) from the microcomputer 15 calculated based on the speed command is converted into a DC voltage Ed that has been smoothed by the LPF 25.
2 ′ is output from the voltage command changeover switch 21 as the DC voltage Ed ′, and the voltage control signal Ve formed from the DC voltage Ed ′ is supplied to the voltage comparator 7. Accordingly, the DC voltage Ed at the capacitor 5 becomes, for example, 150
On / off control of the switch element 6 is performed so that the voltage becomes an arbitrary voltage equal to or higher than V. At the same time, since the drive signal switching switch 22 is switched to the contact B side, the voltage Ei for driving the inverter 13 at a duty ratio of 100% is applied to the inverter driving circuit 16 via the drive signal switching switch 22. Supplied to

Here, the above operation of this embodiment when the input AC power supply voltage is 100 V will be described in more detail with reference to FIG. 3, taking the case of the heating operation of the air conditioner as an example. FIG. 3 is the same as FIG. 1 except that the room temperature sensor 29 is additionally shown.

In the figure, the air conditioner is provided with a room temperature sensor 29, and the microcomputer 15 detects the room temperature with the room temperature sensor 29 (this detected temperature is hereinafter referred to as a measured room temperature). This is compared with a desired room temperature (set room temperature) set by the user, and when the measured room temperature is low and does not reach the set room temperature, the duty ratio of the PWM signal is increased in accordance with the difference between the measured room temperature and the room temperature. The rotation rate of the motor 14 is increased by increasing the duty ratio of the switch element.

At this time, the DC voltage Ed of the capacitor 5,
That is, the DC power supply voltage of the inverter 13 is fixed at 150 V, and the switch element of the inverter 13 is performing a chopper operation.
If the measured room temperature does not reach the set room temperature even when the measured room temperature reaches 0%, the microcomputer 15 switches the drive signal changeover switch 22 to the contact B side to change the constant voltage Ei to the inverter drive circuit as described in step 117. 16, the duty ratio of the switch element of the inverter 13 is maintained at 100%, and at the same time, the voltage command changeover switch 21 is switched to the contact A side, and the PWM signal is smoothed by the LPF 25. The obtained voltage Ed2 ′ is supplied to the voltage comparator 7 as the voltage Ed ′. Then, the duty ratio of the PWM signal is made smaller than 100% so that the voltage Ed 'becomes smaller than the reference voltage Eo.

As a result, the duty ratio of the switch element 6 becomes larger than the duty ratio when the DC voltage Ed of the capacitor 5 is 150 V.
DC voltage Ed sequentially increases from 150 V, and the rotation speed of the electric motor 14 increases. At the same time, the room temperature further increases, and the measured room temperature reaches the set room temperature.

As described above, when the input AC power supply voltage is 100
In the case of V, by switching each switch, it becomes possible to output the drive control signal of the switch element 6 and the inverter 13 from the microcomputer 15 through a single port, and the duty ratio of the switch element of the inverter 13 is 100%. In this case, a command voltage Ed2 ′ (PWM signal) for changing the DC voltage Ed as the power supply voltage of the inverter 13 is output, and if less than 100%, a control voltage (PWM signal) for driving the inverter 13 is output. Output. In each of these cases, the drive circuit 1 of the inverter 13
Means for switching between a predetermined constant voltage for driving the switching element of the inverter 13 at a duty ratio of 100% and an inverter driving signal (PWM signal) from a single port of the microcomputer 15 as a signal to be input to 6 With the provision of the (drive signal changeover switch 22), even if a relatively low-function and inexpensive microcomputer is used as the microcomputer 15, the above-described control becomes possible, and an inexpensive product can be supplied.

When the duty ratio becomes 100%, the DC voltage Ed obtained by the capacitor 5 is controlled to control the rotation speed of the motor 14.

Accordingly, when the ON / OFF duty ratio of the switch element of the inverter 13 is less than 100%, the DC voltage Ed1 'is compared with a constant reference voltage Eo.
Since the switching speed of the electric motor 14 is controlled by turning on and off the switching element of the inverter 13 at an arbitrary duty ratio after setting the constant value to a comparatively low arbitrary value of about 150 V, the inverter 13 or the electric motor 14 is controlled. And the efficiency can be improved.

Further, when the duty ratio of the switch element of the inverter 13 is 100%, an arbitrary command voltage Ed2 'is switched instead of the DC voltage Ed1' and supplied to the voltage comparator 7 to compare with the reference voltage Eo. Then, the command voltage Ed2 'is changed in accordance with the desired rotation speed of the motor 14, and thus the chopper is not performed by the inverter 13 and the DC voltage value Ed is controlled to be large or small. Since the height is controlled, chopper loss in the inverter 13 can be reduced.

By such a rotation control, the switching loss in the inverter 13 can be reduced, and the efficiency can be improved by driving the motor 14 with the low DC voltage by the inverter, so that the efficiency can be increased.

FIG. 4 is a diagram showing a comparison between the motor speed and the efficiency of this embodiment and a conventional air conditioner under a certain motor load.
B shows the characteristics of this embodiment that performs the above operation when the voltage is 00 V, and B denotes a conventional air conditioner in which the DC power supply voltage of the inverter is kept constant, or 200 V in the input AC voltage.
The characteristics of this embodiment performing the above operation when V is shown, respectively.

In the figure, an air conditioner (hereinafter referred to as a known air conditioner) in which the DC power supply voltage of the inverter is kept constant at, for example, 300 V and the number of rotations of the motor is controlled by controlling the duty ratio of the chopper of the inverter. ), The efficiency is represented by a characteristic B with respect to the number of rotations n (rpm) of the motor.
It changes like The reason why the efficiency increases as the number of revolutions n increases is because the duty ratio of the chopper of the inverter increases.

On the other hand, when the input AC power supply voltage is 100 V
As described above, when the duty ratio of the chopper of the inverter is less than 100%, the DC power supply voltage of the inverter becomes 1
The rotation speed of the motor is controlled by controlling the duty ratio of the chopper with the inverter at a constant 50 V, and the duty ratio becomes 10%.
0%, an embodiment in which the number of rotations of the motor is controlled by controlling the DC power supply voltage of the inverter (hereinafter, an embodiment)
With an input of 100 V), the efficiency of the electric motor changes as indicated by a characteristic A with respect to the rotation speed N of the electric motor, and is considerably higher than the efficiency B of the conventional air conditioner.

Here, the region n ₁ is a region where the duty ratio of the chopper is less than 100% in the inverter in the embodiment of input 100 V, and the region n ₂ is a region where the duty ratio of the chopper is in the inverter in the embodiment of input 100 V. 100% area, and the maximum possible rotation of the motor at the boundary between the areas n ₁ and n ₂ , that is, when the inverter is chopper-driven at a DC power supply voltage of 150 V with respect to the motor load. The number is 4000 (rpm). In any case, the DC power supply voltage of the inverter is 300
At V, when the energization of the switch element of the inverter is 100%, the rotation speed of the electric motor is 9000 (rpm).

In a known air conditioner, the DC power supply voltage of the inverter is set to 300 V in the entire region including the regions n ₁ and n ₂ ,
The rotation speed of the electric motor is controlled by controlling the duty ratio of the switch element of the inverter. In contrast, input 100
In embodiments and V, in the region n _1, a DC power supply voltage of the inverter as a half of 150V for 300 V, the control of the duty ratio of the inverter switching elements, speed control of the motor is performed. Therefore, the lower the DC power supply voltage of the inverter, the higher the efficiency of the 100 V input embodiment.

In the region n ₂ , in the embodiment of the input of 100 V, the duty ratio of the switch element of the inverter is set to 100.
%, The chopper is not performed by the inverter, and the rotation speed of the motor is controlled by controlling the DC power supply voltage of the inverter. For this reason, the efficiency is substantially constant, but as shown by the characteristic A, the efficiency is higher than that of the known air conditioner because the inverter does not substantially perform the chopper.

It should be noted that the number of rotations of the electric motor is almost 9000 (r
pm), in the 100V input embodiment:
Inverter duty ratio is 100% and its DC power supply voltage is 3
00V, which is the same state as when the duty ratio of the inverter in the known air conditioner becomes 100%, so that the characteristics A and B match.

In the first embodiment shown in FIG.
The power converter is controlled according to the above-described procedure.
By properly setting the resistance values of each of the above, even when the input AC power supply voltage is 100 V or 200 V, any DC voltage Ed can be obtained, and the high power factor with few harmonics can be obtained. It becomes a power converter.

At this time, the detected output voltage of the input current detector 23 is supplied to the microcomputer 15, and when the detected output voltage exceeds a predetermined value, the drive trigger of the switch element 6 (first switch element) is transmitted from the microcomputer 15 to the microcomputer 15. A signal VT is output to start the switching operation. Therefore, when the supply current is large, a stable high power factor can be obtained.

For example, when a resistor is used as the load current detector 9 and a current signal Vi is to be obtained from a voltage generated at both ends of the resistor, it is necessary to generate a sufficient voltage for controlling a small current. Specifically, it is necessary to set the resistance value large. In this case, when the load current increases, the power consumed by the load current detector 9 including this resistor increases, resulting in an increase in loss. Therefore, in order to reduce this loss, the resistance value of the input current detector 23 should be reduced as much as possible, and in order to prevent unstable operation with respect to the minute detection voltage at the time of low load current. When the detected output value is smaller than the predetermined value, the driving of the switch element 6 is prohibited. In this way, unstable operation at low input current is avoided and loss at high input is reduced. In addition, when the input current is low, by preventing the chopper operation of the switch element 6 from being performed, the loss can be reduced and the noise can be reduced.

In FIG. 1, the active converter block 24 includes an active converter driving unit, 1
A circuit switching unit of 00V / 200V, a switching unit of an inverter drive signal and a DC voltage command signal, and the like are divided into blocks and integrated on the same substrate.

By constructing the active converter block 24 on a substrate independent of other circuits, as shown in FIG. 5, a power factor improving circuit composed entirely of passive elements such as a capacitor 26, a reactor 27 and a diode 28 is provided. Q can be replaced, and the peripheral circuit board including the microcomputer 15 and the like can be shared.

FIG. 6 shows an air conditioner using a circuit composed of passive elements as shown in FIG. 5 and an active element, in which the rotation speed of the motor is controlled in accordance with the DC power supply voltage of the inverter. FIG. 2 is a diagram showing a comparison of the output range of the motor with the first embodiment shown in FIG. 1, wherein the horizontal axis represents the number of revolutions N of the motor, and the vertical axis represents the load torque T,
The output W of the motor is represented by N × T.

In the figure, the input current is limited by the capacity (for example, 20 A) of the household breaker, and the air conditioner using the circuit shown in FIG. 5 has a power factor of about 90%. Is also in the lower area of the input limit range (ie,
The range of the output of the motor can be restricted. On the other hand, in the first embodiment, as described above, since the power factor is improved to almost 100%, the area below the X-ray becomes the input restriction range, as shown in FIG. As compared with an air conditioner using a circuit, the effective power applied to the electric motor is increased by approximately 10%. In particular, when the load torque of the electric motor is large, the electric motor is limited by the input restriction range.

When the rotation speed of the motor increases, the maximum output range of the motor is limited by the DC power supply voltage Ed of the inverter. In the air conditioner using the circuit shown in FIG. 5, the DC power supply voltage Ed is, for example, approximately 230 V
, The maximum range is approximately 280 V, and the limit range when Ed = 230 V is indicated by the line Y ′. The output of the motor can be obtained only in the range on the left side of the Y 'line. On the other hand, in the first embodiment, the DC power supply voltage E
d is 300 V in the above example, and
It is variable from V to 300 V, and the limit range at the maximum of 300 V is indicated by the X 'line. This means that the output range of the electric motor has been expanded.

FIG. 7 is a block diagram showing a second embodiment of the air conditioner according to the present invention, wherein reference numeral 30 denotes an AC power supply voltage detector, and portions corresponding to those in FIG. The description of the operation will be omitted.

In the figure, the point different from the first embodiment shown in FIG. 1 is that an AC power supply voltage detector 30 is provided, and the input AC power supply voltage from the AC power supply 1 is detected. The microcomputer 30 detects the input AC power supply voltage based on the detection output signal Vs'. Then, according to the determination result, the DC voltage switch 18
The switching of the synchronization signal switch 20 is controlled in the same manner as in the first embodiment.

In the first and second embodiments, the microcomputer 15 determines the input AC power supply voltage and outputs the control signal.
However, it is obvious that the same effect can be obtained by using a hardware circuit.

FIG. 8 is a block diagram showing a third embodiment of the air conditioner according to the present invention, wherein 31 is an AC / DC changeover switch, 32 is a DC power supply, and portions corresponding to FIG. And duplicate explanations are omitted.

In the figure, in the third embodiment,
DC power supply 32 such as a solar power supply instead of rectifier 2
(For example, about 150 V), so that either the DC power supply voltage EA from now on or the rectified voltage Es from the rectifier 2 can be selected by the AC / DC switch 31. It is possible to function as a circuit.

When the DC power supply 32 is selected, the microcomputer 15 reduces the DC voltage of the capacitor 5 to 16 in FIG.
The same operation as when it is determined to be 0 V or less (step 102) is performed. Therefore, in the third embodiment, the electric motor 14 can be driven by the low-voltage DC power supply 32.

When a DC power supply such as a solar cell is connected to the power supply side of the reactor 3, even if the DC power supply voltage fluctuates,
It can be stabilized to a desired DC voltage Ed. As a result, connection can be made regardless of the power supply voltage fluctuation of a solar cell or the like and the type of DC power supply (solar cell, storage battery, fuel cell, etc.). In addition, the collector of the switch element 6,
Similar effects can be obtained even when a DC power supply such as a solar cell is connected between the emitters via a diode and a reactor.

When the output DC voltage EA of the DC power supply 32 is higher than the DC voltage Ed obtained by full-wave rectification of the input AC power supply voltage from the AC power supply 1, the AC / DC changeover switch 31
, And the motor control may be performed by the DC power supply 32, or the circuit may be switched in advance by manual operation.

When a DC power supply such as a solar cell is connected to the smoothing capacitor 5 via a diode (not shown), if the output voltage of the DC power supply has reached the desired DC voltage, Power is supplied from the DC power supply, and when the desired DC voltage is not reached, power is supplied from the AC power supply to boost the voltage to the desired DC voltage, thereby turning on and off the switching element of the inverter 13. By controlling the rotation speed of the electric motor 14 by using the AC power source, the commercial AC power source can be used in combination with the DC power source, and power can be saved.

FIG. 9 is a block diagram showing a fourth embodiment of the air conditioner according to the present invention. The parts corresponding to those in FIG.

In the drawing, the difference from the first embodiment shown in FIG. 1 is that the microcomputer 15 also has the functions of the DC voltage switch 18, the voltage command switch 21 and the drive signal switch 22. And that the output port to the inverter drive circuit 16 and the output port to the voltage comparator 7 are provided independently.

As in the first embodiment, the microcomputer 15 switches the synchronization signal changeover switch 20 according to the input power supply voltage.
, And A / D-converts and reads the divided DC voltage Ed1 of the DC voltage Ed in the microcomputer 15. Then, according to the value of the divided DC voltage Ed1, a DC voltage Ed ′ corresponding to the input AC power supply voltage of 100V or the input AC power supply voltage of 200V is obtained, and the DC voltage obtained by integration is obtained by the DC voltage Ed. A PWM signal having a duty ratio such that 'is formed and output. This PW
The M signal is smoothed by the low-pass filter 25 and the DC voltage E
d ′, which is supplied to the voltage comparator 7.

The operation by the software corresponds to the DC voltage E at the smoothing capacitor 5 in the first embodiment and the like.
The switching operation of the DC voltage changeover switch 18, the voltage command changeover switch 21, and the drive signal changeover switch 22 is controlled in accordance with d to select one of the divided voltages Ed1 and Ed2. As compared with the case of the operation by such hardware, the configuration is simplified and the same control operation can be performed.

The signal supplied from the microcomputer 15 to the inverter drive section 16 is a constant voltage Ei of a predetermined value when the duty ratio of the switch element (second switch element) of the inverter 13 is 100%. If this duty ratio is 1
If less than 00%, the control voltage (PWM signal) for driving the inverter 13 is used.

Also, as the DC voltage Ed ′ supplied to the voltage comparator 7, when the above-mentioned duty ratio is 100%,
A command voltage Ed2 ′ (PWM signal) for changing the DC voltage Ed is set. This PWM signal is smoothed by the low-pass filter 25 to be a DC voltage Ed ′, which is supplied to the voltage comparator 7.

On the other hand, when the duty ratio is less than 100%, the microcomputer 15 obtains a predetermined low DC voltage Ed 'from the divided DC voltage Ed2 (or DC voltage Ed), integrates the low DC voltage Ed', and integrates the low DC voltage Ed '. PWM of duty ratio which becomes voltage Ed '
Generate and output a signal. This PWM signal is smoothed by the low-pass filter 25 to become a DC voltage Ed ′, which is supplied to the voltage comparator 7.

Therefore, the peripheral circuit such as a switch for switching the voltage is provided with the same function in the microcomputer 15, so that the number of parts is greatly reduced especially when a multi-stage switching is required. And the routing of wiring to each switch is reduced,
The reliability, including the noise resistance, is greatly improved.

In the embodiment shown in FIGS. 7 to 9, similarly to the embodiment shown in FIG. 1, the operation described in FIGS. 2 and 3 is performed, and the effects described in FIGS. It goes without saying that it can be obtained.

As described above, when the motor load is large,
For example, when the heating load is large, such as when the outdoor air temperature is low such as -10 ° C. or -15 ° C., in order to increase the heating capacity, the rotational speed of the compressor driving motor is variably controlled by the PAM control described above. It was possible to continuously operate at a required high rotation speed (in the above embodiment, the set maximum rotation speed was 9000 rpm). The variable speed control of the compressor driving motor by the PAM control described above can perform control corresponding to a change in the heating load as shown in FIG.

On the other hand, as shown in FIG. 11, in the case of driving the electric motor by PWM control, when the outdoor temperature is low, the driving torque is insufficient and the heating speed of the various compressors is sufficient to the required number of revolutions. Cannot drive. Also,
When a large capacity compressor is used, even when the outdoor temperature is low, it can be rotated to the required rotation speed,
In low-load conditions, such as when the outdoor temperature is high, the heating capacity is excessive, and the operation is frequently interrupted.This causes frequent fluctuations in room temperature, impairing comfort and reducing power consumption. Make it bigger. The above is the case of heating, but the same tendency is shown during cooling, although the degree is different.

In addition, by using a circuit configuration in which both the PWM control and the PAM control can be used in combination with the inverter, power-saving operation under a low load and high-capacity operation under a high load can be performed.
That is, when the outdoor temperature is high and the load is low, the compressor driving motor is operated in a state where the driving voltage is low and the number of revolutions is low and the motor efficiency is good by the PWM control, so that the operation with low power consumption can be performed. When the outdoor air temperature is low, the operation is switched to the PAM control, the driving voltage is increased, and the compressor driving electric motor is operated at a high rotation speed, so that the operation with the required heating capacity is possible.

FIG. 12 is a diagram showing an AC power supply input waveform before and after operation as an active converter.

Compared with the waveform before the operation shown in FIG.
Since the waveform after the operation shown in FIG. 3B is shaped so as to follow the sine wave of the input voltage, the power factor is approximately 100%, and the power factor is 70% or less before the operation. FIG. 9C shows the power factor improvement of the analog system, which is about 90%.

FIG. 13 is a waveform diagram showing the reactor 3 current and the inverter current (flow from the capacitor 5 to the inverter 13) before and after the PWM / PAM switching.

FIG. 13A shows a waveform in the case of a relatively low rotation speed and a low load, and shows the reactor current before switching. O
N indicates the ON time of the switch element, and the chopper cycle is the active converter chopper cycle.

FIG. 13B shows the inverter current before switching, and the chopper cycle is the chopper of the inverter, and r is the ripple of the chopper component.

FIG. 13 (c) shows a case of a relatively high rotation speed and a high load, and shows the waveform of the reactor current after switching, which is similar to the waveform shown in FIG. 13 (a).

FIG. 13D shows the inverter current.
This is the inverter current after switching, and has a smooth curve waveform.

FIG. 14 is a diagram showing the waveform of the reactor current when the voltage is controlled to be constant at 150 V by PWM control in response to a load change.

FIG. 14A shows a waveform in the case of a light load, and FIG.
(B). FIG. 14 (c) shows a waveform in the case of a high load, and FIG.
(D).

As is clear from FIG. 14, if the DC voltage is the same (150 V), the duty of the switching element of the converter is the same, and the waveform height of the current changes depending on the size of the load.

FIG. 15 is a diagram showing a waveform of a reactor current with respect to a DC voltage.

FIG. 15A shows a PWM region of a relatively low rotation speed and a constant voltage (150 V). FIG. 15B shows an enlarged time axis of the part b. FIG.
(C) is a variable voltage at a relatively high rotation speed with a high load (150 to
3 shows a PAM control area of 300 V). FIG. 15D shows an enlarged time axis of the d part.

When comparing the waveforms shown in FIGS. 15C and 15D, in the PAM control region, the ON duty increases.
In the PAM control region, even when there is no load, the ON duty is increased to increase the DC voltage.

In combination with the above-described embodiment of the air conditioner having the electric motor driving device, realization of a comfortable and low power consumption heating operation in a cold region (including a case where a heating load is large at the start of operation in a region other than a cold region) and a refrigerant. by the suppressing condensing pressure low <br/> Ku, a refrigerant discharge pressure of the compressor to prevent an increase in the compression work amount when high, is intended to reduce power consumption, to allow this 16 and 17 show an embodiment of an air conditioner having a refrigeration cycle for
This will be described with reference to FIG.

FIG. 16 is a side sectional view of the indoor unit according to this embodiment.

In the same figure, reference numeral 101 denotes an indoor heat exchanger having a multi-stage (three-stage) bending structure incorporated in the indoor unit. It is configured so as to be thermally separated into a portion from 103 to the back portion 104. In addition, reference numeral 126 denotes an indoor auxiliary heat provided at a position in the refrigerant flow path that is upstream of the indoor heat exchanger 101 during dehumidification operation or cooling operation, and downstream of the indoor heat exchanger 101 during heating operation. It is an exchanger. In these heat exchangers, 120 indicated by a circle is a heat transfer tube provided so as to penetrate a plurality of radiating fins 123, and 121 and a broken line 122 are connection tubes between the heat transfer tubes 120. Further, reference numeral 105 denotes a dehumidifying throttle device which performs a throttling operation during the dehumidifying operation. The upper front portion 103 and the rear portion 104 of the indoor heat exchanger 101 are thermally integrally connected, and the dehumidifying throttle device 105 is connected by a connection pipe 106. , And the other connection port of the dehumidifying expansion device 105 is connected via a connection pipe 107 to the lower front portion 102 of the indoor heat exchanger 101 which is thermally separated.

Also, 109 is a once-through fan type indoor fan, 110 is a front suction grill, 111 is a whole upper suction grill, 112 is an upper rear suction grill, 113 is a filter, 114 is a rear casing, 115 is an outlet, 11
Reference numeral 6 denotes an air outlet wind direction plate.
As shown in arrows 191, 192, and 193, the refrigerant is sucked through the filter 113 from the front suction grill 110, the entire upper suction grill 111, and the upper rear suction grill 112, respectively. After the heat exchange, the air is blown into the room from the air outlet 115 through the indoor fan 109.

Reference numeral 117 denotes a dew tray for the front portions 102 and 103 of the multi-stage bending indoor heat exchanger 101, and 118 denotes a dew tray for the rear portion 104 of the multi-stage bending indoor heat exchanger 101, which is generated during a cooling operation or a dehumidifying operation. Works to receive dehumidified water.

FIG. 17 shows the dehumidifying throttle device 1 shown in FIG.
17A is a cross-sectional view showing a specific example, and FIG. 17A shows the operation state of the dehumidifying expansion device 105 during the dehumidifying operation.
7 (b) is a dehumidifying throttle device 10 for cooling and heating operations.
5 shows the respective operation states. In FIG.
Is a valve body, 131 is a valve seat, 132 is a valve body, 133 is a valve portion of the valve body 132, 134 and 135 are connection pipes, 136 is an electromagnetic motor for moving the valve body 132, and furthermore, a white arrow 138 and 139 indicate the directions of refrigerant flow (pipe direction) and arrows 14
0 indicates the refrigerant flow direction during the dehumidifying operation.

During the dehumidifying operation, the valve 132 is closed by the electromagnetic motor 136 as shown in FIG. At this time, the high-pressure condensed liquid refrigerant that has passed through the indoor auxiliary heat exchanger 126 serving as the condenser and the portions 103 and 104 (FIG. 16) from the upper front to the rear of the indoor heat exchanger 101 flows from the connection pipe 134. , Valve 1
Narrow passage 137 constituted by a gap between valve 33 and valve seat 131
Flows as shown by an arrow 140, where the refrigerant is subjected to a throttling action to become a low-pressure / low-temperature refrigerant, and then passes through a connection pipe 135 to serve as an evaporator.
(FIG. 16).

As a result, in FIG. 16, the portions 103 and 104 from the upper front to the back of the indoor auxiliary heat exchanger 126 and the indoor heat exchanger 101 are heaters (reheaters).
In addition, the front lower portion 102 serves as a cooler to heat the indoor air and at the same time to perform a dehumidifying operation of cooling and dehumidifying.

In the cooling operation and the heating operation, FIG.
As shown in (b), the valve body 132 of the dehumidifying throttle device 105 is pulled up by the electromagnetic motor 136 to be fully opened. As a result, the connecting pipes 134 and 135 communicate with almost no flow resistance, and the refrigerant flows with almost no resistance.

FIG. 18 is a diagram showing the overall cycle configuration of this embodiment, wherein 150 is a compressor for refrigerant compression whose capacity is variable by controlling the number of revolutions, 151 is a four-way valve for switching the operation state, and 152 is The outdoor heat exchanger 153 is a motor-operated expansion valve that can be fully opened without a throttling effect, and further includes the indoor auxiliary heat exchanger 126, the multi-stage bending indoor heat exchanger 101, and the dehumidifying throttle device 105. These are connected in a ring by connecting pipes to form a refrigeration cycle.

In FIG. 18, the indoor auxiliary heat exchanger 12
6 and 6 schematically show an embodiment of the flow path state of the heat transfer tubes of the multi-stage bending indoor heat exchanger 101. The indoor auxiliary heat exchanger 126 has a heat transfer tube constituted by a single refrigerant passage 159, and is connected to the indoor heat exchanger 101 by a connection pipe 129.

[0142] The indoor heat exchanger 101 is
3 and the rear portion 104 are integrally connected so that the heat transfer tubes are formed into two systems of refrigerant flow paths 154 and 155, and the lower heat exchanger portion 102 thermally separated by the cutting line It is constituted by refrigerant channels 156 and 157 of the system. Furthermore, the refrigerant flow path 15 of these heat transfer tubes
4, 155 and the refrigerant flow paths 156, 157 are connected by connecting pipes 106, 107 via the dehumidifying expansion device 105. 158 is an outdoor fan.

In the above indoor unit structure and refrigeration cycle configuration, during the dehumidification operation, the four-way valve 151 is switched in the same manner as during the cooling operation, and the dehumidification expansion device 105 is appropriately squeezed to fully open the electric expansion valve 153. , The refrigerant is supplied to the compressor 150 and the four-way valve
1, an outdoor heat exchanger 152, an electric expansion valve 153, an indoor auxiliary heat exchanger 126, an upper part 1 on a front surface of the indoor heat exchanger 101
03, a rear portion 104, a dehumidifying throttle device 105, a lower front portion 102 of the indoor heat exchanger 101, a four-way valve 151,
The refrigerant is circulated in the order of the compressor 150, and the outdoor heat exchanger 152 is connected to the upstream condenser, the indoor auxiliary heat exchanger 126 and the front upper part 103 and the rear part 104 of the indoor heat exchanger 101 are connected to the downstream condenser and the indoor heat exchanger. Lower part 102 on the front side of exchanger 101
Is operated so as to be an evaporator.

When the indoor air is caused to flow by the indoor fan 109 as shown by arrows 191, 192, and 193, the indoor air is cooled and dehumidified by the front lower heat exchanger portion 102 acting as an evaporator. The condenser on the downstream side, that is, the indoor auxiliary heat exchanger 126 serving as a heater, and the front upper and lower portions 103 and 104 of the indoor heat exchanger are heated, and these airs are mixed and blown into the room. You.

In this case, the rotation speed is controlled to
Of the cooler 102 and the heater 1 by controlling the airflow capacity of the indoor fan 109 and the outdoor fan 158.
26, 103, and 104 can be adjusted, and the amount of dehumidification and the temperature of the blown air can be changed in a wide range.

Next, as described above, when there is no indoor auxiliary heat exchanger 126 during the dehumidifying operation, the front upper part 103 and the rear part 10 of the indoor heat exchanger 101 acting as a reheater are operated.
The reason why the room temperature is lowered in spite of the existence of 4 is described.

Referring to FIG. 16, in such a fan structure, 70% of the suction air flowing in the directions of arrows 191, 192, and 193 is the air flowing in the direction shown by arrow 191 from the front of the panel, and the remaining air flows. 30% are arrows 192, 1
When air is flowing in the direction of 93 and the heat exchanger acting as a cooler is arranged in the upper stage and the reheater is arranged in the lower stage,
Since the dehumidifying water is evaporated again by the reheater and does not dehumidify, the heat exchanger acting as a cooler must be arranged in the lower part on the front side, and the reheater and the cooler are arranged as shown in FIG. The air flowing through the upper front portion 103 and the rear portion 104 acting as a reheater is smaller than the air flowing through the lower front portion 102 acting as a cooler. However, there is a problem that the room temperature is lowered.

In this embodiment, during the dehumidifying operation, the indoor auxiliary heat exchanger 126 acting as a reheater is provided in the ventilation path, so that a decrease in temperature during the dehumidifying operation can be suppressed. Further, since the indoor auxiliary heat exchanger 12 is provided on the reheating side, the amount of heat exchange of the reheater increases, the amount of refrigerant condensed increases, and the capacity of the entire cycle improves. In addition, the gas phase of the gas-liquid two-phase flow that causes the refrigerant flow noise is reduced, and the refrigerant flow noise during the operation of the dehumidifying expansion device 105 (during the dehumidification operation) can be reduced.

As described above, according to this embodiment, during the dehumidifying operation, the upstream side of the dehumidifying expansion device in the indoor auxiliary heat exchanger and the thermally split indoor heat exchanger are respectively provided with the heater 101 and the heating device. The air drawn into the indoor unit was heated by the heater 101 and the heater 102 and simultaneously cooled by the cooler to remove moisture. Thereafter, the water is mixed and blown out, so that a comfortable dehumidifying operation without excessive cooling can be performed. In particular, since the number of heaters is two, the heat transfer area of the heater is sufficiently larger than the heat transfer area of the cooler, and the heating capacity is increased, so that a comfortable dehumidifying operation without excessive cooling can be performed.

Further, a heater (the indoor auxiliary heat exchanger 126) is provided below the cooler (the lower front portion 102 of the indoor heat exchanger).
And part 1 from the upper front to the back of the indoor heat exchanger
03, 104) is not arranged, so that the dehumidified water generated in the cooler does not reach the heater and re-evaporate.

Next, during the cooling operation, the dehumidifying expansion device 1
05, the electric expansion valve 153 is appropriately throttled, and the refrigerant is circulated as indicated by the solid line arrow, so that the outdoor heat exchanger 152 is used as a condenser, the indoor auxiliary heat exchanger 126 and the multi-stage bending indoor heat exchanger 101. Is used as an evaporator to cool the room.

During the heating operation, the four-way valve 151 is switched to open the dehumidifying throttle device 105 and the electric expansion valve 15 is opened.
3 is appropriately throttled, and the refrigerant is circulated as indicated by the dashed arrow, whereby the multi-stage bending indoor heat exchanger 101 is used as a condenser, the indoor auxiliary heat exchanger 126 is used as a subcooler, and the outdoor heat exchanger 152 is evaporated. To heat the room.

And, for each operation of cooling and heating,
It is necessary to ensure the cycle performance and the heat exchange performance in the multi-stage bending indoor heat exchanger 101 and the indoor auxiliary heat exchanger 126 to operate efficiently.

Hereinafter, this method will be described.

First, in FIG. 18, in the cooling operation, the refrigerant flows from the indoor auxiliary heat exchanger 126 to the multi-stage bending indoor heat exchanger 101, and both of these heat exchangers have a low pressure and a large specific volume of the gas refrigerant, and thus have a large volume. Since the evaporator has a large flow rate, if the flow path area is small, the pressure loss here becomes large and the performance of the cycle is reduced. So, here,
Refrigerant channels 154 and 155 and refrigerant passages 156 and 157, respectively, of the portions 103 and 104 from the front upper stage to the rear surface and the front lower portion 102 of the multistage bending indoor heat exchanger 101 which is the main heat exchanger There is a line. As a result, the pressure loss in the refrigerant flow path is sufficiently reduced, and the performance degradation due to this is sufficiently reduced. Furthermore, since the indoor auxiliary heat exchanger 126 is provided, or the indoor heat exchanger 101 is provided from the front to the back, and the heat transfer area as the evaporator can be sufficiently increased, the performance can be improved, and the performance is improved as a whole. It is possible.

Further, in order to improve the performance in the heating operation, it is necessary to take sufficient supercooling at the outlet of the indoor heat exchanger serving as a condenser. In the supercooling region, the refrigerant is in a liquid state and the refrigerant temperature gradually decreases from the condensing temperature, so that the speed of the liquid refrigerant flow is increased to increase the heat transfer coefficient in the heat transfer tube, and the heat transfer tube is It is necessary to exchange heat with an airflow having a relatively low temperature before the heat exchange so as to be on the windward side. Further, the indoor heat exchanger 10
Since the temperature of the high-temperature gas refrigerant is reduced to the condensing temperature at the inlet portion of the lower front portion 102 of the first heating section 102 during the heating operation, it is preferable that the refrigerant flow and the air flow also be in the counterflow at this portion.

The indoor auxiliary heat exchanger 126 is preferably arranged with a gap of 1 mm to 5 mm between itself and the indoor heat exchanger 101. By providing such a gap, it is possible to prevent dew condensation from being bridged between the two heat exchangers at the time of cooling between the indoor heat exchanger 101 and the indoor heat exchanger 101, and to prevent an increase in ventilation resistance of the heat exchanger to improve the cooling capacity. It is possible to prevent a drop and an increase in blowing sound.

Further, if the arrangement position is made to overlap the heat exchanger on the rear surface on the upper surface in the airflow direction, the wind speed of the airflow is slowed and it becomes difficult for the dew to drop toward the fan. , The vertical dimension of the heat exchanger can be reduced, whereby the height of the indoor unit can be reduced or the size of the heat exchanger can be increased accordingly. Furthermore, if the position of the heat exchanger is placed on the heat exchanger on the rear side of the upper surface in the airflow direction, the uniformity of the wind speed distribution will be ensured when an air purifying filter or deodorizing filter is disposed in front of the heat exchanger on the upper front side. As a result, a decrease in heat exchange performance can be suppressed.

In FIG. 18, the outlet side of the condenser is an indoor auxiliary heat exchanger 126, which has a single refrigerant flow path and can have a sufficiently small flow path area. Can be made sufficiently high, and furthermore, it is arranged on the windward side of the indoor heat exchanger 101. Therefore, the indoor auxiliary heat exchanger 126 can exhibit sufficient performance as a subcooler. In addition, in the lower part 102 of the front surface of the indoor heat exchanger, which has the refrigerant flow passages 156 and 157 and two refrigerant flow passages, a piping configuration in which the inlet side of the high-temperature gas refrigerant flow at the time of heating operation is provided on the leeward side of the air flow. In the heat exchanger portion 102 , the refrigerant flow and the air flow are made to flow in opposite directions,
Thereby, heat exchange performance can be improved.

Here, when the indoor unit dimensions cannot be made sufficiently large, the indoor auxiliary heat exchanger 126 may not be sufficiently large as a subcooler in the heating operation. One embodiment that can solve this problem is shown in FIG. In addition,
Parts corresponding to those in FIG. 18 are denoted by the same reference numerals, and redundant description will be omitted.

In FIG. 19, portions 103 and 10 from the upper front to the back of the multi-stage bending indoor heat exchanger 101 are shown.
4 is one of the refrigerant flow passage portions 160 and 2 provided on the windward side.
And the refrigerant flow path portions 161 and 162 of the system. Further, the refrigerant flow path of the lower front part 102 of the indoor heat exchanger 101 is made into two systems of the refrigerant flow paths 156 and 157, and at the same time, the refrigerant inlet part of the lower front part 102 during the heating operation is located on the leeward side of the air flow. The piping configuration is provided.

With this cycle configuration, in the heating operation, the high-temperature and high-pressure gas refrigerant that has left the compressor 150 and passed through the four-way valve 151 enters the indoor heat exchanger 101 , and flows through the refrigerant flow path of the front lower part 102. Has two heat transfer tubes 156,1
After passing through the flow path 57, it passes through the fully opened dehumidifying expansion device 105 to enter the portions 103 and 104 from the front upper stage to the rear surface of the indoor heat exchanger 101. 161 and 162 are divided and flow, and then merged and the refrigerant flow path flows through the heat transfer tube 160 of one system,
Further, a refrigerant flow path flows through the indoor auxiliary heat exchanger 126 of one system.

In this case, in the lower front portion 102 of the indoor heat exchanger 101, the inlet side where the high-temperature gas refrigerant flows is the leeward side of the airflow, and the outlet side where the two-phase refrigerant flows is the leeward side of the low-temperature airflow. Therefore, in the front lower portion 102, the refrigerant flow and the air flow are in a counterflow state with excellent heat exchange performance. Further, the heat transfer tube 160 on the refrigerant outlet side of the portions 103 and 104 from the front upper stage to the rear surface of the multi-stage bending indoor heat exchanger 101 and the heat transfer tube 1 of the indoor auxiliary heat exchanger 126
Reference numeral 59 designates a single-system refrigerant flow path. Further, these heat transfer tubes 160 and 159, which are subcooled regions in which the temperature gradually decreases from the saturation temperature, exchange heat with the low-temperature upstream airflow. Subcooling is taken, and the refrigerant temperature from the indoor unit to the outdoor unit becomes almost room temperature, so that the heating performance can be improved.

Further, in the cooling operation, the two-phase refrigerant which has been throttled by the electric expansion valve 153 to have a low pressure and a low temperature first enters the indoor auxiliary heat exchanger 126 and passes through the heat transfer tube 159 having a single refrigerant flow path. Street, then enter the indoor heat exchanger 101,
Heat exchanger sections 103, 10 from the upper front to the rear
After passing through one heat transfer tube 160 at 4, it is split and enters two heat transfer tubes 161, 162, and further passes through the dehumidifying expansion device 105 and enters the front lower portion 102, and two heat transfer tubes 156. , 157. In this case, in the heat transfer tubes 159 and 160, the dryness of the refrigerant is relatively small, so even in one refrigerant flow path, the pressure loss is relatively small.
Further, in the portions of the heat transfer tubes 161 and 162 and the heat transfer tubes 156 and 157 having relatively large dryness, the pressure loss is sufficiently reduced because the refrigerant flow paths are provided in two systems. As a result, a decrease in cooling performance due to pressure loss can be prevented. Further, by providing the indoor auxiliary heat exchanger 126, the heat transfer area as the evaporator increases, and the cooling performance improves.

In the embodiment shown in FIGS. 18 and 19, the case where the heat transfer tube of the indoor heat exchanger 101 is divided into two systems and the case where one system and two systems are combined are described.
The refrigerant flow path is not limited to these, and the refrigerant flow path can be divided into more systems.
01 can be reduced, and in particular, a decrease in cooling performance can be prevented. However, if the number of refrigerant channels is too large, the pressure loss of the refrigerant flow is reduced, but the heat transfer coefficient is significantly reduced, and the performance of the air conditioner as a whole in the cooling operation and the heating operation is reduced. Because
It is necessary to set the optimal number of refrigerant channels. This optimum number of systems is mainly determined according to the inner diameter of the refrigerant pipe.

Further, in the indoor heat exchanger 101, the same effect can be obtained by using a single-system refrigerant flow path (not shown) in which the multi-system refrigerant flow path is formed as a large-diameter heat transfer tube. That is, by increasing the diameter of the pipe, the flow velocity of the refrigerant flow is reduced, and it is possible to prevent performance deterioration particularly in the cooling operation.

Further, since the indoor auxiliary heat exchanger 126 in FIGS. 16, 18 and 19 is provided on the windward side of the indoor heat exchanger 101 with respect to the airflow, the indoor auxiliary heat exchanger 126 In the overlapping portion of the vessels 101, the air flow decreases and the heat transfer performance decreases due to an increase in ventilation resistance. Therefore, the indoor auxiliary heat exchanger 126 needs to have a smaller ventilation resistance than the indoor heat exchanger 101. For this purpose, the indoor auxiliary heat exchanger 126 has a larger fin pitch, a smaller depth dimension (dimension in the direction in which the wind flows), or a smaller indoor heat exchanger than the indoor heat exchanger 101. A structure in which the slits are not provided for the fins 101 in order to improve the heat transfer performance is omitted (not shown).

Next, in the indoor unit structure of FIG. 16, arrows 191, 192,
The wind speed distribution of the suction air indicated by reference numeral 193 indicates that the lower front portion 10
191 corresponding to 2 is relatively fast. Further, from the design point of view , as shown in FIG.
There is a case where the upper unit 180 is closed so that the air inlet is not used, and only the lower portion is an intake grill 181. In this case, the wind speed distribution of the intake air flow indicated by arrows 191, 192, and 193 is indicated by the front surface. The wind speed distribution of the arrow 191 corresponding to the lower suction grill 181 is the fastest.

In such a case, a representative example is shown in FIG. 20 (in FIG. 20, portions corresponding to FIG. 16 are denoted by the same reference numerals and redundant description will be omitted). By providing it on the windward side of the lower front portion 102 of the bending indoor heat exchanger 101, the performance of cooling and heating can be further improved.

That is, in cooling and heating operations, arrow 1
Since the air volume corresponding to the air volume 91 is relatively large, even if the heat exchanger portion composed of the indoor auxiliary heat exchanger 126 and the lower front portion 102 of the indoor heat exchanger corresponding to this air volume becomes thicker in the depth direction in which the wind flows. The temperature efficiency of this heat exchanger section is kept relatively high. Furthermore, since the auxiliary heat exchanger 126 having (somewhat) a ventilation resistance is provided at a place where the wind speed distribution is high in the indoor heat exchanger 101, the indoor heat exchanger 1
01, the distribution of the suction wind speed on the front surface becomes more uniform. As a result, the indoor unit structure shown in FIG.
The cooling and heating performance can be improved as compared with the indoor unit structure shown in FIG.

According to actual measurements, the performance of the dehumidifying operation in the structure shown in FIG. 20 is not much different from the indoor unit structure shown in FIG. 16 (although the amount of dehumidification tends to decrease slightly, The air temperature tends to rise), and a comfortable dehumidifying operation in which excessive cooling is suppressed can be performed.

Further, in the case where the indoor auxiliary heat exchanger 126 cannot be provided on the windward side of the rear part 104 or the windward side of the front lower part 102 of the indoor heat exchanger due to the structural limitation of the indoor unit. Although the performance may be somewhat reduced even if it is provided on the windward side of the front upper section 103 of the indoor heat exchanger, the effect of the auxiliary heat exchanger in the dehumidification, cooling and heating operations described above is obtained. be able to.

In the cycle configuration shown in FIGS. 18 and 19, the indoor unit structure or the indoor auxiliary heat exchanger 126 shown in FIG.
The indoor unit structure provided on the windward side of No. 03 can be applied, and the same effect can be obtained (not shown).

By the way, in the embodiment shown in FIGS. 16, 18, 19 and 20, the indoor heat exchanger 101 is divided into the front lower part 102, the front upper part 103 and the rear part 1
04 is bent in three steps, but is not limited to this, and each part may be configured in multiple steps as needed.

As an example, FIG.
The lower part 102 ′ of the front side of the indoor heat exchanger 101, which is the lower part of 63,
This shows a case where the tiers are arranged. According to such a configuration, the heat transfer area can be made larger than in the configuration of FIG.

Further, as another example, as shown in FIG. 22, the lower front part to the upper front part and the rear part are not a broken line but have a continuous curved and integral structure. The section from the upper section to the back section and the lower section on the front section serving as a cooler are indicated by cutting lines 167.
The heat exchanger portions 168 and 169 may be configured so as to be thermally separated from each other. Similarly, the heat transfer area can be increased.

In particular, in the case of a room air conditioner, which is a small-sized air conditioner, the space for accommodating the indoor heat exchanger is often insufficient, and in this case, the number of bending times of the indoor heat exchanger is increased. In this case, the indoor heat exchanger having a sufficient heat transfer area can be accommodated in a narrow space. Also, in the case of these indoor heat exchangers, FIG.
As shown in FIG. 6 or FIG. 20, a similar effect can be obtained by providing an indoor auxiliary heat exchanger on the windward side of the indoor heat exchanger.

The dehumidifying throttle device 105 and the electric expansion valve 153 in FIGS. 16, 18, 19, and 20 have a configuration in which a capillary tube or a normal expansion valve and a two-way valve are provided in parallel. (Not shown), and the same operation as in the previous embodiments can be realized by opening and closing the two-way valve.

[0179] Heretofore, the structure in which the indoor heat exchanger is provided from the front to the rear of the indoor unit has been considered, but the present invention is not limited to this, and the indoor heat exchanger is provided only on the front of the indoor unit. Also in the case of an indoor unit structure in which an auxiliary heat exchanger is provided on the windward side with a structure not provided on the rear side (not shown; for example, in FIG.
01 is not provided), it is possible to obtain the same effect of the indoor auxiliary heat exchanger 126 as described above.

Further, the refrigerant flow paths in the front part and the rear part of the indoor heat exchanger may each be divided into two or more systems, or the refrigerant flow path of the indoor auxiliary heat exchanger 126 may be made one system, and In the cooling operation or the heating operation, the pressure loss can be reduced, and the refrigerant flow and the air flow can be made to flow in opposite directions, and further, during the heating operation,
The indoor auxiliary heat exchanger 126 acts as a subcooler, and can efficiently and sufficiently subcool. Accordingly, in the cooling operation and the heating operation, a sufficiently efficient operation can be performed as in the embodiment described with reference to FIGS.

In the embodiment described above, the case where a single refrigerant such as HCFC22 (abbreviation of hydrochlorofluorocarbon 22) often used in an air conditioner is used has been described. However, recently, research on alternative refrigerants replacing HCFC22 has been actively conducted in view of ozone layer depletion and global warming. As alternative refrigerants, use of not only a single refrigerant but also a mixed refrigerant has been studied. . On the other hand, it is clear that the control method of the structure, cycle configuration and operation of the indoor unit described in the embodiment shown in FIGS. 16 to 20 can be applied, and the same effects can be obtained.

According to an experiment with an air conditioner equipped with the indoor auxiliary heat exchanger 126, at -10 ° C and -15 ° C, the suction density of the refrigerant gas is lower at -10 ° C,
The reduction in the amount of compression work allowed the compressor driving motor to operate at a high rotation speed for a long time. This is because the increase in the amount of refrigerant condensed by the indoor auxiliary heat exchanger 126 suppresses or decreases the pressure of the refrigerant gas sucked into the compressor, thereby reducing the work of the compressor, thereby reducing the operating current value. As a result, the current does not reach the limit current value even if the operation at the set maximum rotation speed (9000 rpm) is performed for a long time.

Thus, in the experiment using only the PAM control, under the conditions where the outdoor air temperature is −10 ° C. and −15 ° C., the condensing pressure increases before the indoor temperature reaches the set temperature of 23 ° C., and the current reaches the limit current. The rotation speed from 5000 rpm to 7
The control was limited to 000 rpm, and it sometimes took an extremely long time to reach the set temperature. However, this could be eliminated. This is the outdoor temperature -1
Even at 5 ° C., the heating capacity was the same as that of the oil fan heater, and the electricity rate was equal to the oil cost of the oil fan heater.

[0184]

As described above, according to the present invention,
During heating operation when the outdoor temperature is low, the power supply voltage of the inverter can be increased and the compressor motor can be operated at a high rotation speed for a long time, reducing the time required for the indoor temperature to reach the set temperature. In addition to making it possible to achieve comfortable heating, sufficient supercooling can be obtained at the outlet of the indoor heat exchanger, which serves as a condenser, during heating operation, so that the work of the compressor can be reduced, thereby improving heating performance. It is possible to improve power consumption.

According to the present invention, the outdoor air temperature is -10
During heating operation at ℃ ℃ or lower or -15 ℃ or lower, the power supply voltage of the inverter can be maximized and the compressor motor can be operated at the maximum rotation speed for a long time. The time required to reach the set temperature can be shortened, and comfortable heating can be realized.At the time of heating operation, sufficient supercooling can be obtained at the outlet of the indoor heat exchanger that serves as a condenser. The work volume of the machine can be reduced, thereby improving the heating performance and saving power.

Further, according to the present invention, since the subcooling auxiliary heat exchanger is arranged on the windward side of the indoor heat exchanger, in addition to the above-described effects, the indoor air flow is heated to a higher temperature. As a result, the work amount of the compressor can be further reduced, thereby obtaining an excellent effect that the heating performance can be further improved and significant power saving can be achieved.

Furthermore, according to the present invention, since the subcooling auxiliary heat exchanger is arranged on the windward side of the indoor heat exchanger and on the refrigerant passage downstream of the indoor heat exchanger, In addition to the above effects, it is possible to heat the indoor airflow to a higher temperature, further reduce the work of the compressor, further improve the heating performance, and achieve significant power savings. Excellent effects can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of an air conditioner according to the present invention.

FIG. 2 is a flowchart illustrating a control method according to the first embodiment illustrated in FIG. 1;

FIG. 3 is a diagram for explaining the control method shown in FIG. 2 when the input AC power supply voltage is 100 V in the first embodiment shown in FIG. 1;

FIG. 4 is a diagram showing the effect of the control method described in FIG. 3 in comparison with a conventional example.

FIG. 5 is a block diagram showing a modification of the first embodiment shown in FIG. 1;

6 is a diagram showing a comparison between the effects of the first embodiment shown in FIG. 1 and an air conditioner using the circuit shown in FIG. 5;

FIG. 7 is a block diagram showing a second embodiment of the air conditioner according to the present invention.

FIG. 8 is a block diagram showing a third embodiment of the air conditioner according to the present invention.

FIG. 9 is a block diagram showing a fourth embodiment of the air conditioner according to the present invention.

FIG. 10 is a circuit configuration diagram of a motor drive device in a conventional air conditioner.

FIG. 11 is a diagram showing heating characteristics with respect to outside air temperature.

FIG. 12 is a diagram showing an AC power supply input waveform immediately after operation as an active converter in one embodiment of the present invention.

FIG. 13 is a diagram showing a reactor current and an inverter current before and after switching between PWM / PAM.

FIG. 14 is a diagram showing a waveform of a reactor current with respect to a load operation.

FIG. 15 is a diagram showing a waveform of a reactor current with respect to a DC voltage.

FIG. 16 is a diagram showing an indoor unit structure of an air conditioner according to an embodiment of the present invention.

FIG. 17 is a diagram showing a structure and an operation state of an example of the dehumidifying throttle device in FIG. 1;

FIG. 18 is a diagram showing a cycle configuration of an air conditioner according to an embodiment of the present invention.

FIG. 19 is a diagram showing a piping configuration of an indoor heat exchanger according to another embodiment of the present invention.

FIG. 20 is a diagram showing an indoor unit structure of an air conditioner according to another embodiment of the present invention.

FIG. 21 is a view showing a shape of an indoor heat exchanger according to another embodiment of the present invention.

FIG. 22 is a view showing a shape of an indoor heat exchanger according to still another embodiment of the present invention.

[Explanation of symbols]

 2 Rectifier 3 Reactor 4 Diode 5 Capacitor 6 Switch element 7 Voltage comparator 8 Multiplier 9 Load current detector 10 Current comparator 11 Oscillator 12 Drive circuit 13 Inverter 14 Motor 15 Microcomputer 16 Inverter drive circuit 18 DC voltage signal changeover switch 19 Trigger Element 20 Synchronous signal changeover switch 21 Voltage command changeover switch 22 Drive signal changeover switch 23 Supply current detector 24 Active converter block 25 Low pass filter 26 Power supply capacitor 27 Reactor 28 Diode 29 Room temperature sensor 30 AC power supply voltage detector 31 AC / DC changeover switch 32 DC power supply Q Power factor improving circuit 101 Indoor heat exchanger 102, 102 'Lower front part of indoor heat exchanger 103 Upper front part of indoor heat exchanger 104 Surface portion 105 Dehumidifying expansion device 106, 107 Connection piping 109 Indoor fan 110 Front suction grill 111 Top suction grill 112 Rear suction grill 113 Filter 114 Rear casing 115 Blow outlet 116 Blow outlet wind direction plate 117 Front dew tray 118 Rear dew tray 120 Transmission Heat pipes 121, 122 Connection pipes for heat transfer pipes 123 Radiation fins 124 Thermal cutting lines 126 Indoor auxiliary heat exchangers 127 to 129 Connection pipes 130 Valve bodies 131 Valve seats 132 Valve bodies 133 Valve parts 134, 135 Connection pipes 136 Electromagnetic motor 137 Dehumidification Refrigerant flow path during operation 150 Compressor 151 Four-way valve 152 Outdoor heat exchanger 153 Electric expansion valve 154 to 157, 159 to 162 Refrigerant flow path 158 Outdoor fan 163,167 Thermal cutting line 164 to 166,168,169 Heat exchange Bowl part 80 front upper panel 181 front lower suction grille 191-193 indoor suction air flow

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI // H02P 7/63 302 H02P 7/63 302K (72) Inventor Mio Motoo 800, Tomita, Ohira-cho, Shimotsuga-gun, Tochigi Hitachi, Ltd. Cooling Business Division (72) Inventor Makoto Ishii 800, Tomita, Ohira-machi, Shimotsuga-gun, Tochigi Prefecture Hitachi, Ltd. Cooling Business Division (56) References JP-A-7-113555 (JP, A) JP-A-4- 26374 (JP, A) JP-A-10-2575 (JP, A) JP-A 55-83622 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F24F 11/02 102 F25B 1/00 361 H02M 3/155 H02M 7/217 H02M 7/48 H02P 7/63 302

Claims (5)

(57) [Claims] A compressor for compressing a refrigerant, which operates in a cooling and heating operation.
Switching four-way valve, outdoor heat exchanger, expansion valve and indoor heat
Refrigeration cycle in which exchangers are connected in a ring by connecting pipes
And a motor drive unit for the compressor that drives the motor for the compressor.
The compressor motor drive device rectifies and smoothes an input AC voltage to generate an output DC voltage,
A power converter that variably controls the output DC voltage; and a compressor that uses the output DC voltage of the power converter as a power supply voltage.
With an inverter that drives the rotation speed of the motor
AndThe power converter makes its output DC voltage variable,  The indoor heat exchanger is different from the indoor heat exchanger.This indoor heat exchanger
Heating placed on the indoor air intake side, which is the windward side
Used for super cooling during operationWith auxiliary heat exchanger, outdoor temperature
During the low heating operation, the output DC voltage of the power converter is increased.
Thus, even if the compressor motor is operated at a high speed,
Has a refrigerant condensate that maintains a lower operating current than the current limit
An air conditioner characterized by its size. 2. A compressor for compressing a refrigerant, which operates in a cooling / heating operation state.
Switching four-way valve, outdoor heat exchanger, expansion valve and indoor heat
Refrigeration cycle in which exchangers are connected in a ring by connecting pipes
And a motor drive unit for the compressor that drives the motor for the compressor.
The compressor motor drive device rectifies and smoothes an input AC voltage to generate an output DC voltage,
A power converter that variably controls the output DC voltage; and a compressor that uses the output DC voltage of the power converter as a power supply voltage.
With an inverter that drives the rotation speed of the motor
The indoor heat exchanger is different from the indoor heat exchanger.The power converter is
The output DC voltage is made variable,  The indoor heat exchanger is different from the indoor heat exchanger.This indoor heat exchanger
Heating placed on the indoor air intake side, which is the windward side
Used for super cooling during operationWith auxiliary heat exchanger, outdoor temperature
During the heating operation at −10 ° C., the output DC power of the power converter
Operating the compressor motor at the maximum speed with the maximum pressure.
Refrigerant condensation that maintains an operating current even lower than the limiting current
An air conditioner characterized by having a size having a volume. 3. A refrigeration cycle comprising a refrigerant compression compressor, a four-way valve for switching a cooling / heating operation state, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger connected in a ring by a connection pipe. A compressor motor drive device for driving the motor, the compressor motor drive device rectifying and smoothing the input AC voltage to generate an output DC voltage,
A power converter that variably controls the output DC voltage; and an inverter that uses the output DC voltage of the power converter as a power supply voltage and variably drives a rotation speed of the compressor motor. The heat exchanger includes an indoor heat exchanger and the indoor heat exchanger .
Heating placed on the indoor air intake side, which is the windward side
An auxiliary heat exchanger for supercooling during operation , and operating the compressor motor at the maximum rotation speed by maximizing the output DC voltage of the power converter during a heating operation at an outdoor temperature of -15 ° C. An air conditioner having a size having a refrigerant condensing amount that maintains an operation current lower than a limit current. 4. A refrigeration cycle comprising a refrigerant compression compressor, a four-way valve for switching a cooling / heating operation state, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger connected in a ring by a connection pipe. A compressor motor drive device for driving the motor, the compressor motor drive device rectifying and smoothing the input AC voltage to generate an output DC voltage,
A power converter that variably controls the output DC voltage; and an inverter that uses the output DC voltage of the power converter as a power supply voltage and variably drives a rotation speed of the compressor motor. The heat exchanger includes an indoor heat exchanger and the indoor heat exchanger .
Heating placed on the indoor air intake side, which is the windward side
An auxiliary heat exchanger that is used for supercooling during operation , and in a heating operation in which the outdoor temperature is low, the output DC voltage of the power converter is increased to operate the compressor motor at a high rotation speed. An air conditioner having a size having a refrigerant condensed amount that maintains an operation current lower than a limit current. 5. A refrigeration cycle in which a compressor for refrigerant compression, a four-way valve for switching between a cooling and heating operation state, an outdoor heat exchanger, an expansion valve and an indoor heat exchanger are connected in a ring by connecting pipes. A compressor motor drive device for driving the motor, the compressor motor drive device rectifying and smoothing the input AC voltage to generate an output DC voltage,
A power converter that variably controls the output DC voltage; and an inverter that uses the output DC voltage of the power converter as a power supply voltage and variably drives a rotation speed of the compressor motor. The heat exchanger includes an indoor heat exchanger and the indoor heat exchanger.
Subcooling auxiliary heat for supercooling during heating operation , which is arranged on the suction side of indoor air, which is on the windward side, and is located on the refrigerant passage downstream of the indoor heat exchanger with a small flow passage area. An air conditioner, when the outdoor temperature is low, the operating current is lower than the limiting current even when the compressor DC motor is operated at a high rotation speed by increasing the output DC voltage of the power converter. An air conditioner having a size having a condensed amount of refrigerant to be maintained.