JPH10111028A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power loss in an inverter and thereby improve efficiency by variably controlling the relational speed of a compressor driving electric motor with the aid of PAM(pulse amplitude modulation) and disposing an indoor auxiliary heat exchanger in the downstream side of an indoor heat exchanger at the time of heating operation to lower the condensation pressure. SOLUTION: In an electric motor driving device applied to an electric motor 14 in an air conditioner in which an indoor auxiliary heat exchanger is disposed downstream of an indoor heat exchanger at the time of heating operation, there are provided an electric power converter including a switch element 6 for switching on and off a rectification output of a rectifier 2 connected to an Ac power supply 1 and an inverter 13 for switching on an off input voltage to convert it to an alternating current. When the rotational speed of the motor is less than a predetermined value, the motor 14 is driven with output voltage obtained by chopper controlling a current in an on-interval of the switching element of the inverter 13 while when the speed is more than the predetermined value, conductivity of the switching element 6 is controlled, and the electric motor 14 is driven with output voltage where the conductivity in the on-interval ratio of the switching element of the inverter 13 is made 100%.

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 by an inverter at a variable speed.
In particular, 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, and this air conditioner The present invention relates to an electric motor driving device used for a motor.

[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 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 conceivable to raise it.

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, 2a, 2b, 2
c and 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, 10 is a current comparator, and 11 is an oscillator. , 12 is a drive circuit, 13 is an inverter, 14 is a motor, 15 is a microcomputer, 16 is an inverter drive circuit, and 17 is a modulator.

In FIG. 1, 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.

[0008] The AC power supply voltage from the AC power supply 1 is full-wave rectified by a rectifier 2 comprising diodes 2a to 2d, and is converted into a rectified voltage Es. This rectified voltage Es is applied to the capacitor 5 via the reactor 3 and the diode 4,
A smoothed DC voltage Ed is obtained. A switching element 6 is provided in parallel with the diode 4 and 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 the deviation between the DC voltage Ed' and the reference voltage Eo is determined 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 also includes resistors 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. With this switching drive signal Vg, the drive circuit 12 drives the switching element 6 on and off.

As described above, in this conventional example, the switching element 6 is turned on and off while following the waveform of the rectified voltage Es in the form of a sine wave, whereby the input AC current i is changed at a high power factor. A sinusoidal current with few harmonics can be obtained, and the conduction ratio of the switching 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, “an energy-saving air conditioner GD series adopting a new dehumidifying method: Toshiba Review, Vol. 51, No. 2, 1996, pp. 67-70 ”(Literature 1), recently, the indoor heat exchanger is provided from the front to the back of the indoor unit, or the indoor heat exchange during the heating operation is performed. An air conditioner provided with an indoor auxiliary heat exchanger used as a subcooler downstream of the heat exchanger has been developed.

[0015]

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. Is extremely low and the walls and furniture are very cold, the drive torque by the PWM control is not so large, and the rotational speed control for improving the efficiency is not sufficient because the drive torque is insufficient. It could not be rotated up to the number of revolutions, and could not reach the set room temperature or it took 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. Would. 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 an input current of the air conditioner in consideration of an 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 this condensation pressure is high, the compression work of the compressor will be large,
This has led 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, even in the case of an air conditioner in which the indoor heat exchanger is made sufficiently large in the indoor unit, and further, the air conditioner provided with the indoor auxiliary heat exchanger, the piping configuration of the indoor heat exchanger and the air It is necessary to improve the heat transfer performance of the indoor heat exchanger as much as possible in each of the cooling and heating operations and maintain the performance of the refrigeration cycle sufficiently high by devising the relationship with the flow and the like.

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, but the DC voltage Ed depends on the voltage value of the input AC power supply voltage. When it is desired to change the lever DC voltage Ed, it is necessary to correct the circuit constant. In particular, in the above 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 by the following equation: DC voltage Ed ≧ AC power supply voltage × 1.41 + 10 [V] In the case of, 15
The DC voltage Ed is set to 0 V or more, and the DC voltage Ed is set to 300 V or more when the input AC power supply voltage is 200 V.

Therefore, if the AC power supply 1 is
In the case of a power converter that can use either of the above, the set value of the DC voltage Ed needs to be 300 V or more.

For example, in the case of an input AC power supply voltage of 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. However, in the above-described conventional example, since this point is not taken into consideration, there is a problem that the loss is increased more than necessary.

In the above-mentioned conventional example, the sine-wave rectified voltage Es obtained by full-wave rectification of the AC power supply voltage from the AC power supply 1 is divided by the 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 a sine wave form with reference to i ′, the rectified voltage Es is different between the AC power supply voltages of 100 V and 200 V, and the shapes and values of the sine waves are significantly different between the two. Therefore, the AC power supply voltage is set to 100
When shared between V and 200V, the power converter has a low power factor and a high harmonic content.

Further, in the motor drive device and the air conditioner using the above 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 required, it is considered to conversely eliminate unstable operation, loss, noise, etc. 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, a sufficient voltage is generated for controlling a small current. More 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 inverter 13 can respond 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.

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

[0031]

In order to achieve the above-mentioned object, the rotation speed of a compressor driving motor is controlled by PAM (Pulse Amplitude Modulation) control, and the indoor heat exchange of the refrigerant flow path during a heating operation is performed. It is conceivable to arrange an indoor auxiliary heat exchanger downstream of the vessel to lower the condensation pressure.

That is, the object is to provide a compressor for compressing a refrigerant, an indoor heat exchanger into which the refrigerant from the compressor flows,
An indoor auxiliary heat exchanger disposed downstream of the indoor heat exchanger in the refrigerant flow path during the heating operation, an electric motor for driving the compressor, and an electric motor for supplying an AC voltage to the electric motor to drive the electric motor A power converter comprising: a rectifier for rectifying an input AC voltage; a first switch element for turning on and off a rectified output of the rectifier to control a voltage; An inverter that drives a motor with this AC voltage, including a second switch element for turning the input voltage on and off and converting the input voltage to AC, and an inverter for driving the motor with the AC voltage. Control means for controlling the ON / OFF duty ratio, ON / OFF control of the second switch element, and chopper control of the current during the ON period, the control means controlling the number of rotations of the motor to a predetermined number of times. If the number is less than the number, the motor is driven by the output voltage obtained by chopper-controlling the current during the ON period of the second switch element, and if the number of rotations of the motor exceeds a predetermined number of rotations, the first switch element is turned on and off. This is achieved by controlling the off duty ratio to obtain an output voltage corresponding to the rotation speed, and by providing an air conditioner that drives the electric motor with an output voltage whose duty ratio during the on period of the second switch element is set to 100%. You.

Another object of the present invention is to provide a power converter having a rectifier for rectifying an input AC voltage, a first switch element for turning on and off a rectified output of the rectifier to control a voltage, and An inverter for driving an electric motor for driving the compressor with the AC voltage, comprising a second switch element for converting an input voltage to an AC voltage by turning the input voltage on and off; In an air conditioner provided with control means for controlling the on / off duty ratio of the element, on / off control of the second switch element, and chopper control of the current during the on-period, the control means includes: When the rotation speed is less than the predetermined rotation speed, the motor is driven by an output voltage obtained by chopper-controlling the current during the ON period of the second switch element, and when the rotation speed of the motor exceeds the predetermined rotation speed, The on / off duty ratio of the first switch element is controlled to obtain an output voltage corresponding to the number of revolutions, and the motor is driven with an output voltage in which the duty ratio of the second switch element during the ON period is set to 100%. This is achieved by using an air conditioner.

[0034]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a first embodiment of an air conditioner according to the present invention, wherein 18 is a DC voltage switch, 19 is a trigger element, 20 is a synchronous signal switch, and 21 is a voltage command switch. Switch, 22 is a drive signal changeover switch, 23 is an input current detector, 24 is an active converter block, and 25 is an LPF (low-pass filter). Parts corresponding to those in FIG. I do.

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 applied to the 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, the voltage control signal Ve is obtained by comparing one type of DC voltage Ed ′ obtained by dividing the DC voltage Ed smoothed by the capacitor 5 with the reference voltage Eo. However, in the first embodiment, one of the 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 used as the DC voltage Ed. 'age,
This is obtained by comparing this 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 waveform of 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.
The 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 equal to or more than a predetermined value. 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), at this point, the trigger element 19 puts the switch element 6 into an operating state.

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, the control operation method according to the first embodiment will be described with reference to FIG. 2, taking the case of Japan as an example. In the case of Japan, the AC power supply voltage is 100 V
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 Ed = Ed1 × (R4 + R5 + R6) / (R5 + R6), if the DC voltage Ed is higher than 160 V, for example (step 102), it is determined that the input AC power supply voltage is 200V. Then, the DC voltage switch 18 is switched to the contact A (step 103). Thereby, the DC voltage E
d '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 (step 102), it is determined that the input AC power supply voltage is 100 V, and the DC voltage switch 18 is kept closed to the contact B (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 the case of 200 V and the case of 200 V, the control instability due to the amplitude of the voltage control signal Ve becoming too large and being saturated,
It is possible to prevent a problem that the current reference signal Vi 'calculated from the sine wave synchronization signal Es' and 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 at 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 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 below 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 a trigger signal VT of “H” to the trigger element 19 during a period when the input AC current Is is large. The operation is continued (step 109) by turning on and off the switch element 6 (step 108).

Even if it is determined in step 102 that the input AC power supply voltage is 100 V, the voltage command 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, the drive signal switching switch 22 is switched to the contact B side, so that a voltage Ei for driving the inverter 13 at a duty ratio of 100% is supplied to the inverter drive circuit 16 via the drive signal switching switch 22. Supplied.

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 by 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 according to these differences, and Of the switch element is increased to increase the rotation speed of the electric motor 14.

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.
Even if the measured room temperature does not reach the set room temperature even if it becomes 0%, the microcomputer 15 switches the drive signal changeover switch 22 to the contact B side to drive the constant voltage Ei to the inverter drive as described in the above step 117. By supplying the current to the circuit 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 so that the PWM is switched.
The voltage Ed2 ′ obtained by smoothing the signal with the LPF 25 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
When the DC voltage Ed of the capacitor 5 is 150 V, the duty ratio becomes larger than the duty ratio. As a result, the DC voltage Ed of the capacitor 5 gradually 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 a drive control signal for the switch element 6 and the inverter 13 from the microcomputer 15 through a single port,
When the duty ratio of the switch element of the inverter 13 is 100%, a command voltage Ed2 ′ (PWM signal) for changing the DC voltage Ed as the power supply voltage of the inverter 13 is output. A control voltage (PWM signal) for driving the inverter 13 is output. And
In each of these cases, a signal input to the drive circuit 16 of the inverter 13 is a predetermined constant voltage for driving the switch element of the inverter 13 at a duty ratio of 100%, or an inverter drive signal from a single port of the microcomputer 15. (PWM signal) and means for switching and outputting (drive signal changeover switch 22), the above-mentioned control becomes possible even if a relatively low-function and inexpensive microcomputer is used as the microcomputer 15, and inexpensive. Products can be supplied.

When the duty ratio reaches 100%, the control of the DC voltage Ed obtained by the capacitor 5 controls the rotation speed of the electric motor 14.

Therefore, 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 for comparison with the reference voltage Eo. Then, the command voltage Ed2 ′ is changed in accordance with the desired rotation speed of the electric 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.

With this rotation control, it is possible to reduce the switching loss in the inverter 13 and to improve the efficiency by driving the motor 14 with the low DC voltage by the inverter, thereby achieving higher efficiency.

FIG. 4 is a diagram showing a comparison between the motor speed and the efficiency of this embodiment and a conventional air conditioner at a certain motor load, wherein A indicates that the input AC power supply voltage is 1 unit.
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 an inverter is kept constant at, for example, 300 V and the number of rotations of a motor is controlled by controlling the duty ratio of a chopper of the inverter. ), The efficiency is represented by a characteristic B with respect to the rotational speed 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)
According to the embodiment (input of 100 V), the efficiency 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 the input of 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 the input of 100 V. The maximum rotation that the motor can take when the inverter is chopper-driven at the boundary between the regions N ₁ and N ₂ , that is, when the DC power supply voltage of the inverter is 150 V, with respect to the motor load here. 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 , 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 procedure, and the resistance values of the resistors R1, R2, and R3 are determined for the sine wave synchronization signal Es ', and the resistance values of the resistors R4, R5, and R6 are determined for the DC voltage Ed'.
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 becomes a predetermined value or more, the microcomputer 15 drives the switch element 6 (first switch element) to trigger the drive. 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 between both ends, a voltage sufficient for controlling a small current is generated. It is necessary to set the resistance value to be 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 forming the active converter block 24 on a circuit board independent of other circuits, as shown in FIG. 5, a power factor improving circuit composed 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, wherein the number of revolutions of the motor is controlled according to 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, and is 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. 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 by the AC power supply voltage detection. 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, in which 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. In FIG. 9, portions corresponding to those in FIG.

In the figure, the difference from the first embodiment shown in FIG. 1 is that the microcomputer 15 also has the functions of a DC voltage switch 18, a voltage command switch 21 and a drive signal switch 22. And an output port to the inverter drive circuit 16 and an 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 in 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 driving 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 for 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 operations described in FIGS. 2 and 3 are 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., it is necessary to variably control the motor for driving the compressor by the above-described PAM control in order to increase the heating capacity. Continuous operation was possible at a very high rotation speed (in the embodiment, the set maximum rotation speed of 9000 rpm). The variable speed control of the compressor driving electric motor by the above-described PAM control can perform control corresponding to a change in the heating load as shown in FIG.

On the other hand, as shown in FIG. 11, when the electric motor is driven by PWM control, the driving torque is insufficient when the outdoor air temperature is low, and the heating capacity of the various compressors is reduced to a required rotational speed. It cannot be driven sufficiently. In addition, when a large capacity compressor is used, it can be driven to rotate at a required rotational speed even when the outdoor temperature is low, but when the load is small such as when the outdoor temperature is high, the heating capacity can be increased. However, the intermittent operation is frequently repeated, so that the room temperature frequently fluctuates up and down, thereby impairing comfort and increasing power consumption. Although the above description has been made with reference to heating, a similar tendency is exhibited even during cooling, although the degree is different.

In addition, by using a circuit configuration in which both PWM control and PAM control can be used in combination with the inverter, power saving operation at low load and high capacity operation at high load can be performed. In other words, when the outdoor temperature is high and the load is low, the compressor driving motor is driven 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 compressor is switched to the PAM control, the driving voltage is increased, the compressor driving motor is operated at a high rotation speed, and the operation with the required heating capacity is possible.

FIG. 12 shows the AC power supply input waveform before and after the operation as the active converter. Compared with the waveform before (a), the waveform after (b) shapes the current waveform following the sine wave of the input voltage, so the power factor is approximately 100%, and before the operation, it is 70% or less. is there. (C) shows the power factor improvement of the analog system, which is about 90%.

FIG. 13 shows the reactor 3 current and the inverter current (flow from the capacitor 5 to the inverter 13) before and after the PWM / PAM switching. (A) is a case of a relatively low rotation speed and a low load, and is a reactor current before switching. ON indicates the ON time of the switch element, and the chopper cycle is the active converter chopper cycle.

(B) is the inverter current before switching, the chopper cycle is the chopper of the inverter, and r is the ripple of the chopper component. (C) shows the case of a relatively high rotation speed and a high load, and shows the waveform of the reactor current after switching. The waveform is similar to that of FIG. (D) is the inverter current, which is the inverter current after switching, and has a smooth curve waveform.

FIG. 14 shows 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. (A) shows the case of light load, and (b) is an enlarged view of the time axis of the part b in (a). (C)
Shows the case of high load, and (d) shows an enlarged view of the time axis of the d part of (c). As is apparent from FIG. 14, when 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 shows 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). (B) is an enlarged view of the time axis of the part b in (a). (C)
Is voltage variable (150-300
V) shows a PAM control area. An enlarged view of the time axis of the d part of (c) is shown in (d). Comparing the waveforms of (c) and (d), the ON duty increases in the PAM control area. In the PAM control region, even if there is no load, the ON duty increases because the DC voltage is increased.

In combination with the above-described embodiment of the air conditioner equipped with the motor driving device of the present invention, a 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 the cold region) and a small power consumption is performed. By realizing and suppressing the condensation pressure of the refrigerant, it is possible to prevent an increase in the compression work amount when the refrigerant discharge pressure of the compressor is increased, and to reduce the power consumption. One embodiment of an air conditioner having a cycle is shown in FIG.
This is shown in FIG. 17 and FIG. FIG. 16 is a diagram illustrating a side cross section of the indoor unit according to the present embodiment. In FIG. 16, 1
Reference numeral 01 denotes an indoor heat exchanger having a multi-stage (three-stage) bending structure incorporated in the indoor unit, and a lower front portion 102 and an upper front portion 103 of the indoor unit are cut by a thermal cutting line 124.
And a portion extending from the rear portion 104 to the rear portion 104. 126 is a refrigerant flow path,
During the dehumidifying operation or the cooling operation, the indoor heat exchanger 101
Of the indoor heat exchanger 101 during the heating operation.
This is an indoor auxiliary heat exchanger provided at a position downstream of the indoor heat exchanger.
In these heat exchangers, reference numeral 120 denotes a heat transfer tube provided so as to penetrate the plurality of heat radiation fins 123, and reference numerals 121 and 122 denote connection tubes between the heat transfer tubes 120. Reference numeral 105 denotes a dehumidifying throttle device that 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 to each other. It is connected to one connection port, and the other connection port of the dehumidifying expansion device 105 is connected via a connection pipe 107 to the lower part 102 on the front surface of the indoor heat exchanger 101 which is thermally separated.

Reference numeral 109 denotes a once-through fan-type indoor fan, 110 denotes a front suction grill, 111 denotes an entire upper suction grill, 112 denotes an upper rear suction grill, 113 denotes a filter, 114 denotes a rear casing, 115 denotes an outlet, 11
Reference numeral 6 denotes an outlet wind direction plate, and indoor air is filtered by the indoor fan 9 from the front suction grill 110, the entire upper suction grill 111, and the upper rear suction grill 1112 as indicated by arrows 191, 192 and 193, respectively. After passing through the indoor fan 109, the heat is exchanged with the refrigerant in the multi-stage bending indoor heat exchanger 101,
5 is blown out into the room.

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

FIG. 17 is a diagram showing an embodiment of the dehumidifying throttle device 105 in FIG. 16, and FIG.
FIG. 17A is a diagram illustrating an operation state of the dehumidifying throttle device 105 during the dehumidifying operation, and FIG. 17B is a diagram illustrating an operating state of the dehumidifying throttle device 105 during the cooling and heating operations. In these figures, 130 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, Larger arrows 138 and 139 indicate the refrigerant flow direction (pipe direction), and arrow 140 indicates the refrigerant flow direction during the dehumidifying operation.

During the dehumidifying operation, the valve body 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 a condenser and the portions 103 and 104 from the front upper stage to the rear surface of the indoor heat exchanger 101 flows in from the connection pipe 134 and flows into the valve portion 133. Through the narrow passage 137 formed by the gap between the
After flowing as shown by 0, the refrigerant becomes a low-pressure and low-temperature refrigerant under the throttling action, and then flows into the lower front portion 102 of the indoor heat exchanger 101 serving as an evaporator through the connection pipe 135.

As a result, part 1 of the indoor auxiliary heat exchanger 126 and the indoor heat exchanger 101 from the upper front to the rear
03 and 104 are heaters (reheaters), lower part 10 on the front side
2 serves as a cooler, which enables a dehumidifying operation of heating and cooling and dehumidifying indoor air.

At the time of the cooling and heating operations, FIG.
As shown in FIG. 2B, the valve body 132 of the dehumidifying throttle device 105 is pulled up by the electromagnetic motor 136 and is fully opened. As a result, the connection 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 the present embodiment, wherein 150 is a compressor for compressing a refrigerant whose capacity is variable by controlling the number of revolutions, 151 is a four-way valve for switching the operating state, and 152 Is an outdoor heat exchanger, 153 is a motor-operated expansion valve capable of being fully opened without a throttling action, and further includes the indoor auxiliary heat exchanger 126 and the multistage bending indoor heat exchanger 10 described above.
1 and the dehumidifying throttle device 105 are added, and these are connected in a ring by a connection pipe to constitute a refrigeration cycle. FIG. 18 schematically shows one embodiment of the state of the flow path of the heat transfer tubes of the indoor auxiliary heat exchanger 126 and the multistage 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.

[0124] The indoor heat exchanger 101 is
3 and the rear portion 104 are integrally connected to each other, and the heat transfer tubes are configured so as to form two refrigerant passages 154 and 155. Further, the lower heat exchanger portion 102 thermally separated by the cutting line 124 includes 156 and 157. And two refrigerant flow paths. Further, these heat transfer tube refrigerant passages 154, 155
, 156 and 157 are connected by connecting pipes 106 and 107 via a dehumidifying expansion device 105. Further 15
8 is an outdoor fan.

In the above indoor unit structure and refrigeration cycle configuration, during the dehumidifying operation, the four-way valve 102 is switched in the same manner as during the cooling operation, the dehumidifying expansion device 105 is appropriately throttled, and the electric expansion valve 153 is fully opened. As shown by a dashed line, the refrigerant is the compressor 150, the four-way valve 151, the outdoor heat exchanger 152, the electric expansion valve 153, and the indoor auxiliary heat exchanger 12
6. Upper front part 103 and back part 104 of indoor heat exchanger 101, dehumidifying expansion device 105, indoor heat exchanger 10
1 lower part 102, four-way valve 151, compressor 150
, The outdoor heat exchanger 152 is the upstream condenser, the indoor auxiliary heat exchanger 126 and the upper front part 103 and the rear part 104 of the indoor heat exchanger 101 are the downstream condenser and the indoor heat exchanger 101. The operation is performed so that the lower front portion 102 becomes 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 by the front lower heat exchanger portion 1 acting as an evaporator.
At the same time as being cooled and dehumidified in 02, the indoor auxiliary heat exchanger 126, which is a condenser or heater on the downstream side, is heated in the front upper section 103 and the rear section 104 of the indoor heat exchanger, and the air is mixed. Is blown out into the room.

In this case, the rotation speed is controlled to
Of the cooler 102 and the heater 12 by controlling the air blowing capacity of the indoor fan 19 and the outdoor fan 158.
6, 103, 104 capacity can be adjusted, and the dehumidification amount and blown air temperature can be changed in a wide range.

As described above, when the indoor auxiliary heat exchanger 126 is not provided during the dehumidifying operation, the front upper portion 103 and the rear portion 1 of the indoor heat exchanger 101 acting as a reheater are provided.
The reason why the room temperature is lowered in spite of the existence of 04 will be described. Referring to FIG. 16, in such a fan structure, 70% of the intake air of arrows 191, 192 and 193 is air from arrow 191 from the front of the panel, and the remaining 30% is air from arrows 1192 and 193. If it is air and the heat exchanger acting as a cooler is arranged in the upper stage and the reheater is arranged in the lower stage, the dehumidified water will be evaporated again by the reheater and will not be dehumidified. The vessel must be placed in the lower part of the front
As shown in FIG. 6, it is necessary to arrange a reheater and a cooler, and the air flowing through the upper front portion 103 and the rear portion 104 acting as the reheater flows through the lower front portion 102 acting as the cooler. When the temperature is lower than the air and the outside air temperature is low, there is a problem that the room temperature is lowered.

In the present embodiment, since the indoor auxiliary heat exchanger 126 acting as a reheater is provided in the ventilation path during the dehumidifying operation, a decrease in temperature during the dehumidifying operation can be suppressed. In addition, since this indoor auxiliary heat exchanger is provided on the reheating side, the amount of heat exchange of the reheater increases, the amount of refrigerant condensed increases, the capacity of the entire cycle is improved, and the dehumidifying throttle device 1 is provided.
At 05, when the gas phase of the gas-liquid two-phase flow causing the refrigerant flow noise decreases, the dehumidifying throttle device 105 operates (during the dehumidifying operation).
, The flow noise of the refrigerant in the above can be reduced.

As described above, according to the present embodiment, at the time of 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 each provided with the heater 101. , The downstream side of the heater 102 and the dehumidifying expansion device becomes a cooler, and the air sucked into the indoor unit is heated by the heater 101 and the heater 102 and simultaneously cooled by the cooler to remove moisture, and then mixed. The air is blown out, and a comfortable dehumidifying operation without excessive cooling can be performed. In particular, the number of heaters is two, and the heat transfer area of the heater is sufficiently larger than the heat transfer area of the cooler to increase the heating capacity, so that a comfortable dehumidifying operation without excessive cooling can be performed.

Further, a heater (the indoor auxiliary heat exchanger 26 and a part 10 extending from the upper front to the rear of the indoor heat exchanger) is provided below the cooler (the lower front part 102 of the indoor heat exchanger).
3, 104), the dehumidified water generated in the cooler does not reach the heater and re-evaporate.

Next, during the cooling operation, the dehumidifying expansion device 10
5 is opened, the electric expansion valve 153 is appropriately throttled, and the refrigerant is circulated as indicated by the solid line arrow, thereby turning the outdoor heat exchanger 152 into the condenser, the indoor auxiliary heat exchanger 126 and the multi-stage bending indoor heat exchanger 101. The room is cooled as an evaporator.

In the heating operation, the four-way valve 151 is switched, the dehumidifying expansion device 105 is opened, the electric expansion valve 153 is appropriately throttled, and the refrigerant is circulated as indicated by the dashed arrow, so that the multistage bending indoor heat exchanger 101 is operated. The interior of the room is heated by using the condenser and the indoor auxiliary heat exchanger 126 as a subcooler and the outdoor heat exchanger 152 as an evaporator.

For each of the cooling and heating operations, it is necessary to ensure the cycle performance and the heat exchange performance of the multistage 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 is supplied from the indoor auxiliary heat exchanger 126 to the multi-stage bending indoor heat exchanger 10.
1, both of these heat exchangers become low-pressure, large-volume gas refrigerant evaporators with large specific volumes and large volume flow rates.
If the flow path area is small, the pressure loss here becomes large and the performance of the cycle is reduced. Therefore, in FIG. 18, the refrigerant passages of the portions 103 and 104 from the front upper stage to the rear surface and the front lower portion 102 of the multi-stage bending indoor heat exchanger 101 as the main heat exchanger are respectively 154, 155 and 15
6, 157. 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 1 is provided from the front to the back, the heat transfer area as the evaporator can be sufficiently increased, so that the performance can be improved, and the performance can be 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 this supercooling region, the refrigerant temperature is gradually lowered from the condensing temperature at the same time as the refrigerant is in a liquid state, so that the speed of the liquid refrigerant flow is increased to increase the heat transfer coefficient in the heat transfer tube, Is required to be on the windward side to exchange heat with a relatively low-temperature air flow before heat exchange. Furthermore, the indoor heat exchanger 101
Since the temperature of the high-temperature gas refrigerant drops to the condensing temperature at the inlet portion of the lower front portion 102 during the heating operation, it is preferable that the refrigerant flow and the air flow also flow in the opposite direction.

It is preferable that the indoor auxiliary heat exchanger 126 is disposed with a gap of 1 mm to 5 mm between the indoor auxiliary heat exchanger 126 and the indoor heat exchanger 101. By providing such a gap, it is possible to prevent dew that forms during cooling from being bridged between the two heat exchangers with the indoor heat exchanger 101, and to prevent an increase in the ventilation resistance of the heat exchanger to prevent cooling. It is possible to prevent a decrease in performance and an increase in blowing noise.

[0139] When the arrangement position is superposed on the heat exchanger on the rear side of the upper surface in the airflow direction, the wind speed of the airflow is slowed and it is difficult for dew to fall toward the fan. , The vertical dimension of the heat exchanger can be reduced. As a result, the height of the indoor unit can be reduced or the size of the heat exchanger can be increased. In addition, if the airflow filter and the deodorizing filter are arranged in front of the heat exchanger on the upper front side, the wind speed distribution will be uniformed if the arrangement position is placed on the heat exchanger on the upper rear side in the airflow direction. , And 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. This part has a single refrigerant flow path and can have a sufficiently small flow path area. And the indoor heat exchanger 1
It is arranged on the windward side of 01. Therefore, the indoor auxiliary heat exchanger 101 can exhibit sufficient performance as a subcooler.
Further, in the lower part 102 of the front surface of the indoor heat exchanger in which the refrigerant flow path is divided into two systems of 156 and 157, the inlet side of the high-temperature gas refrigerant flow at the time of the heating operation is provided on the leeward side of the air flow. In the vessel portion 2, the refrigerant flow and the air flow are made to flow in opposite directions, so that the heat exchange performance can be improved.

If 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. FIG. 18 shows an embodiment capable of solving this problem.

In FIG. 19, portions 103, 10 from the upper front to the back of the multi-stage bending indoor heat exchanger 101 are shown.
4 is composed of a single-system refrigerant flow path part 160 and two-system refrigerant flow path parts 161 and 162 provided on the windward side. Further, the refrigerant flow path of the front lower part 102 of the indoor heat exchanger 101 is divided into two systems of 156 and 157, and at the same time, the refrigerant flow inlet part of the front lower part 102 during the heating operation is provided on the leeward side of the air flow. It is. The same reference numerals as in FIG. 18 indicate the same parts.

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 1 and has a refrigerant flow path in the front lower portion 102. Are two systems of heat transfer tubes 156, 157
After passing through the heat exchanger, the refrigerant passes through the dehumidifying expansion device 105 which is fully open, enters the portions 103 and 104 from the front upper stage to the rear surface of the indoor heat exchanger 101, and the refrigerant flow passage has two heat transfer tubes 161. , 162, and then merge, the refrigerant flow path flows through one system of the heat transfer tube 160, and the refrigerant flow path flows through the one system of the indoor auxiliary heat exchanger 126.

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. On the other hand, in the lower front portion 102, the refrigerant flow and the air flow are in a counterflow state with excellent heat exchange performance.
Further, the heat transfer tubes 1 on the refrigerant outlet side of the portions 103 and 104 from the front upper stage to the rear surface of the multistage bending indoor heat exchanger 101.
60 and the heat transfer tubes 159 of the indoor auxiliary heat exchanger 126 constitute a single-system refrigerant flow path, and further, these heat transfer tubes 160 and 159 which form a subcool region where the temperature gradually decreases from the saturation temperature are upstream air having a low temperature. A sufficient subcool is taken for heat exchange with the flow, and the refrigerant temperature from the indoor unit to the outdoor unit becomes almost room temperature, so that the heating performance can be improved.

In the cooling operation, the electric expansion valve 1
The low-pressure, low-temperature two-phase refrigerant squeezed at 53 first enters the indoor auxiliary heat exchanger 126, the refrigerant passage passes through one system of the heat transfer tube 159, then enters the indoor heat exchanger 101, and After passing through one system of heat transfer tubes 160 in the heat exchanger portions 103 and 104 from the back to the back, the flow is split and enters the two systems of heat transfer tubes 161 and 162, and further through the dehumidifying expansion device 105 to the front lower portion 102. The heat is split into two heat transfer tubes 156 and 157. In this case, since the dryness of the refrigerant in the heat transfer tubes 159 and 160 is relatively small, the pressure loss is relatively small even in a single-system refrigerant flow path. Heat transfer tubes 161, 162 and 156, 1 having relatively large dryness
In the portion 57, the pressure loss is sufficiently reduced because the refrigerant flow paths are divided into two systems. As a result, a decrease in cooling performance due to pressure loss can be prevented. Furthermore, by providing the indoor auxiliary heat exchanger 126, the heat transfer area as an evaporator increases, and the cooling performance improves.

Here, in the embodiment shown in FIG. 18 and FIG. 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 shown. Instead, it is possible to divide the refrigerant flow path into more systems, and in this case as well, it is possible to reduce the pressure loss of the refrigerant flow in the indoor heat exchanger 101, and particularly to prevent the cooling performance from lowering. 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. Therefore, it is necessary to set an optimal number of refrigerant channels in the system, and the number of systems is determined mainly 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 large-diameter heat transfer tube in a place where the multi-system refrigerant flow path is formed and a single-system refrigerant flow path (not shown). 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 degradation particularly during cooling operation.

Further, the indoor auxiliary heat exchanger 126 shown in FIGS.
1, the auxiliary heat exchanger 126
In the overlapping portion of the indoor heat exchanger 101 and the indoor heat exchanger 101, the air flow decreases due to the increase in ventilation resistance, and the heat transfer performance decreases. 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 is
In contrast to the above, the fin pitch is increased, the depth dimension (dimension in the direction in which the wind flows) is reduced, or the indoor heat exchanger 101 is provided with a slit in the fin in order to improve the heat transfer performance. A structure without a slit is provided (not shown).

Next, in the indoor unit structure shown in FIG. 16, arrows 191, 192, 1 in the multi-stage bending indoor heat exchanger 101 are used.
The wind speed distribution of the suction air indicated by 93
191 is relatively early. Further, from the point of design, as shown in FIG. 19, there is a case where the upper unit 180 is closed at the front surface of the indoor unit so as not to serve as an air suction port, and only the lower portion is a suction grille 181. , 191, 192, 193, the wind speed distribution of the arrow 191 corresponding to the front lower suction grill 181 is the fastest. In FIG. 20, the same reference numerals as in FIG. 16 denote the same parts.

In such a case, as shown in FIG. 20 as a representative example, the auxiliary heat exchanger 126 is
The air conditioner is provided on the windward side of the front lower portion 102, so that the cooling and heating performance can be further improved. That is, in the cooling and heating operations, since the air volume corresponding to the arrow 191 is relatively large, the indoor auxiliary heat exchanger 126 and the lower front portion 10 of the indoor heat exchanger corresponding to this air volume are provided.
Even if the heat exchanger portion composed of 2 becomes thicker in the depth direction in which the wind flows, the temperature efficiency of this heat exchanger portion is kept relatively high. Further, the auxiliary heat exchanger 12 which has (somewhat) a ventilation resistance in a place where the wind speed distribution is high in the indoor heat exchanger 101
6, the suction wind speed distribution on the entire front surface of the indoor heat exchanger 101 becomes more uniform. As a result of these,
The indoor unit structure of FIG. 20 can improve cooling and heating performance as compared with the indoor unit structure of FIG.

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

Furthermore, if the indoor auxiliary heat exchanger 126 cannot be located 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 structural restrictions of the indoor unit, Even on the windward side of the upper front section 103 of the indoor heat exchanger, the effect of the auxiliary heat exchanger in the dehumidification, cooling and heating operations described above can be obtained although the performance may be slightly reduced.

18 and FIG. 19, the indoor unit structure shown in FIG. 20 or the indoor unit structure in which the indoor auxiliary heat exchanger 126 is provided on the windward side of the front upper section 103 of the indoor heat exchanger can be applied. The same effect can be obtained (not shown).

FIG. 16, FIG. 18, FIG. 19, FIG.
In the embodiment, the case where the indoor heat exchanger 101 is bent into three steps of the front lower part 102, the front upper part 103, and the rear part 104 is shown, but the present invention is not limited to this, and each part may be replaced as necessary. May be configured in multiple stages. FIG.
1, the lower part 102 'of the front surface of the indoor heat exchanger 101, which is the lower part of the thermal cutting line 163, is connected to 164, 165, 1
66 shows a case in which there are three stages. Thereby, the heat transfer area can be made larger than in FIG. Further, as shown in FIG. 22, the lower front section, the upper front section, and the rear section have an integrated structure that is not a broken line but a continuous curve, and further, a portion from the front upper section to the rear, which serves as a heater during dehumidifying operation, and a cooler. The lower part of the front surface is connected by 168 and 169 with a cutting line 167.
The structure may be thermally separated into two, and the heat transfer area can be similarly increased. In particular, room air conditioners, which are small air conditioners, often do not have enough room to accommodate the indoor heat exchanger. In this case, the number of bending times of the indoor heat exchanger is increased or the indoor heat exchanger is curved. Thus, the indoor heat exchanger having a sufficient heat transfer area can be stored in a small space. Also in the case of these indoor heat exchangers, a similar effect can be obtained by providing an indoor auxiliary heat exchanger on the windward side of the indoor heat exchanger as shown in FIG. 16 or FIG.

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

[0155] 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. Also, in the case of an indoor unit structure in which an auxiliary heat exchanger is provided on the windward side (not shown; for example, when the rear portion 104 of the indoor heat exchanger 101 is not provided in FIG. 16 or FIG. 20) ), And the effect of the indoor auxiliary heat exchanger 126 similar to that described above can be obtained.

Further, the refrigerant flow paths at the front and rear portions of the indoor heat exchanger may be divided into two or more systems, or the refrigerant flow path of the indoor auxiliary heat exchanger 126 may be formed as one system, and at the same time as the windward side of the indoor heat exchanger. 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. In addition, during the heating operation, the indoor auxiliary heat exchanger 126 acts as a supercooler to improve the efficiency. Good and sufficient supercooling can be taken. Therefore, 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 for hydrochlorofluorocarbon 22) often used in an air conditioner is used has been described. However, in recent years, research on alternative refrigerants replacing HCFC22 has been actively conducted from the viewpoint of depletion of the ozone layer and global warming, and the use of mixed refrigerants as well as single refrigerants as alternative refrigerants is being 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 similar 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., −
At 10 ° C., the suction density of the refrigerant gas was smaller and the compression work was smaller, so that the compressor driving motor could be operated at a higher rotation speed for a longer 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.

As a result, in the experiment using only the PAM control, when the outdoor air temperature is -10.degree. C. and -15.degree. C., the condensing pressure increases before the indoor temperature reaches the set temperature 23.degree. And the rotation speed from 5000 to 700
The control was limited to 0 rpm, which required an extremely long time to reach the set temperature. However, this could be eliminated. This has the same heating capacity as the oil fan heater even when the outdoor air temperature is -15 ° C, and the electricity rate can be made equal to the oil cost of the oil fan heater.

[0160]

As described above, according to the air conditioner of the present invention, the condensing pressure is reduced by employing a cycle configuration in which the indoor auxiliary heat exchanger is provided downstream of the heater during the heating operation. At a predetermined low power supply voltage of the inverter, the rotation speed of the motor is controlled by the chopper operation. When the duty ratio in the chopper operation of the inverter reaches 100%, the rotation speed of the motor is controlled by controlling the power supply voltage of the inverter. Because it is a thing, even a compact indoor unit,
In the cooling and heating operations, the heat transfer area can be made sufficiently large, and particularly in the heating operation, the indoor auxiliary heat exchanger can be effectively used as a subcooler. Power can be saved.

According to the present invention, for example, 300 V
Rather than performing a chopper operation of the inverter at an arbitrary duty ratio with a constant DC voltage of about
Controlling with a DC voltage of 0 V or more without a chopper having a 100% duty ratio can reduce the loss, which is effective for increasing the efficiency.

Furthermore, according to the present invention, the rotation speed of the motor is controlled by the chopper operation at a predetermined low power supply voltage of the inverter, and when the duty ratio of the inverter in the chopper operation reaches 100%, Since the number of rotations of the motor is controlled by controlling the power supply voltage, the chopper loss of the inverter and the loss of the motor can be significantly reduced, and the efficiency can be greatly increased.

[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 3 current and an inverter current before and after PWM / PAM switching.

FIG. 14 is a diagram showing a waveform of a waste 3 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, 1
8 DC voltage signal changeover switch, 19 trigger element, 2
0 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 improvement circuit, 101 ... indoor heat exchanger, 102, 1
02 ': lower front part of indoor heat exchanger; 103: upper front part of indoor heat exchanger; 104: rear part of indoor heat exchanger; 105: dehumidifying throttle device;
7, 128, 129: connection piping, 109: indoor fan,
110: Front suction grill, 111: Top suction grill, 1
12: Rear suction grille, 113: Filter, 114: Rear casing, 115: Air outlet, 116: Air outlet direction plate, 117: Front exposed pan, 118: Rear exposed pan, 120
... heat transfer tubes, 121, 122 ... connection pipes for heat transfer tubes, 123
... heat radiation fins, 124, 163, 167 ... thermal cutting lines,
126 ... indoor auxiliary heat exchanger, 130 ... valve body, 131 ...
Valve seat, 132 ... valve element, 133 ... valve part, 134, 135 ...
Connection pipe, 136: electromagnetic motor, 137: refrigerant flow path during dehumidification operation, 150: compressor, 151: four-way valve, 152: outdoor heat exchanger, 153: electric expansion valve, 154, 155, 1
56, 157, 159, 160, 161, 162: refrigerant flow path, 158: outdoor fan, 164, 165, 166,
168, 169: heat exchanger portion, 180: front upper panel, 181: front lower suction grille, 191, 192, 1
93 ... Indoor unit suction air flow.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor, Motoo Morimoto 800, Tomita, Ohira-cho, Shimotsuga-gun, Tochigi Pref. Inside the cooling division of Hitachi, Ltd.

Claims (7)

[Claims] 1. A compressor for compressing a refrigerant, an indoor heat exchanger into which the refrigerant flows from the compressor, and an indoor auxiliary disposed downstream of the indoor heat exchanger in the refrigerant flow path during a heating operation. A heat exchanger, an electric motor for driving the compressor, and an electric motor drive device for supplying an alternating current voltage to the electric motor to drive the electric motor, wherein the electric motor drive device rectifies an input alternating voltage, A power converter having a first switch element for controlling the voltage by turning on and off the rectified output of the rectifier; and using the output voltage controlled as an input voltage, turning the input voltage on and off to convert the input voltage to an alternating current An inverter for driving an electric motor with the AC voltage, controlling the ON / OFF duty ratio of the first switch element, controlling ON / OFF of the second switch element, and controlling the ON period. Current Tsu consists of a control means for path control, the control means, the rotational speed of the electric motor is less than a predetermined rotational speed, the first
The on / off duty ratio of the switch element is controlled to keep the output voltage constant, and the motor is driven with the output voltage obtained by chopper-controlling the current during the on period of the second switch element. When the rotation speed is exceeded, the on / off duty ratio of the first switch element is set to be larger than the duty ratio in the case of the constant output voltage, and the current during the on-period of the second switch element is not chopper-controlled. An air conditioner characterized by driving a motor with an output voltage. 2. The air conditioner according to claim 1, wherein the indoor auxiliary heat exchanger is arranged via a space having a size of 1 mm to 5 mm from the indoor heat exchanger. 3. The power converter according to claim 1, wherein the first switch element of the power converter turns on and off the rectified output from the rectifier via a reactor to control the voltage, and the voltage is controlled. An air conditioner comprising a smoothing means for smoothing a rectified output to output a DC voltage, and outputting the DC voltage generated by the smoothing means to a second switch element of the inverter. 4. A compressor for compressing a refrigerant, an indoor heat exchanger into which the refrigerant flows from the compressor, and an indoor auxiliary disposed downstream of the indoor heat exchanger in the refrigerant flow path during a heating operation. A heat exchanger, an electric motor for driving the compressor, and an electric motor drive device for supplying an alternating current voltage to the electric motor to drive the electric motor, wherein the electric motor drive device rectifies an input alternating voltage, A power converter having a first switch element for controlling the voltage by turning on and off the rectified output of the rectifier; and using the output voltage controlled as an input voltage, turning the input voltage on and off to convert the input voltage to an alternating current An inverter for driving an electric motor with the AC voltage, controlling the ON / OFF duty ratio of the first switch element, controlling ON / OFF of the second switch element, and controlling the ON period. Current And control means for controlling the motor with an output voltage obtained by chopper-controlling the current during the ON period of the second switch element when the rotation speed of the motor is less than a predetermined rotation speed. If the rotation speed of the electric motor exceeds a predetermined rotation speed, the on / off duty ratio of the first switch element is controlled to output an output voltage corresponding to the rotation speed, and the second switch element is turned on. An air conditioner characterized in that an electric motor is driven by an output voltage with a duty ratio of 100% during a period. 5. A power converter having a rectifier for rectifying an input AC voltage, a first switch element for turning on and off a rectified output of the rectifier to control a voltage, and inputting the voltage-controlled output voltage. A second switch element for converting the input voltage to an AC by turning on / off the input voltage; an inverter for driving a compressor driving motor with the AC voltage; and an ON / OFF switch for the first switch element. In an air conditioner provided with control means for controlling the OFF duty ratio and controlling the ON / OFF control of the second switch element and chopper controlling the current during the ON period, the control means determines that the number of rotations of the motor is a predetermined value. If the rotation speed is less than
The on / off duty ratio of the switch element is controlled to keep the output voltage constant, and the motor is driven with an output voltage obtained by chopper-controlling the current during the on-period of the second switch element. When the rotation speed exceeds the rotation speed, the ON / OFF duty ratio of the first switch element is set to be larger than the duty ratio in the case of the constant output voltage, and the current during the ON period of the second switch element is controlled by chopper control. An air conditioner characterized by driving the motor with an output voltage that does not occur. 6. A power converter according to claim 5, wherein the first switch element of the power converter controls the rectified output from the rectifier on and off via a reactor to control the voltage, and the voltage is controlled. An air conditioner comprising a smoothing means for smoothing a rectified output to output a DC voltage, and outputting the DC voltage generated by the smoothing means to a second switch element of the inverter. 7. A power converter having a rectifier for rectifying an input AC voltage, a first switch element for turning on and off a rectified output of the rectifier to control a voltage, and inputting the voltage-controlled output voltage. A second switch element for converting the input voltage to an AC by turning on / off the input voltage; an inverter for driving a compressor driving motor with the AC voltage; and an ON / OFF switch for the first switch element. In an air conditioner provided with control means for controlling the OFF duty ratio and controlling the ON / OFF control of the second switch element and chopper controlling the current during the ON period, the control means determines that the number of rotations of the motor is a predetermined value. When the rotation speed of the motor is less than the predetermined rotation speed, the motor is driven with an output voltage obtained by chopper-controlling the current during the ON period of the second switch element. The on / off duty ratio of the switch element is controlled to obtain an output voltage corresponding to the number of revolutions, and the motor is driven by an output voltage with the duty ratio during the on period of the second switch element being 100%. And air conditioner.