JPH08159575A - Air conditioner - Google Patents

Abstract

PURPOSE: To provide a highly efficient air conditioner in which the motor voltage of an inverter maintains a predetermined motor voltage-frequency characteristics even if a DC voltage is dropped in the case of the load change of the conditioner. CONSTITUTION: The air conditioner comprises a discharge temperature detector 23 for detecting the load of a compressor 1, a discharge temperature voltage converter 24 for storing the discharge temperature-DC voltage drop characteristics to output a DC voltage drop from the discharge temperature, a voltage calculator 25 for calculating the DC voltage from the voltage drop, a waveform memory 27 for storing the waveform pattern of the different motor voltage-frequency characteristics, and a waveform generator 26 for fetching the pattern of the motor voltage-frequency characteristics to the DC voltage to output a waveform.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner equipped with an inverter device for controlling the rotation speed of a compressor.

[0002]

2. Description of the Related Art In recent years, an air conditioner has been used which controls the capacity by changing the rotation speed of a compressor by using an inverter device which changes the frequency of a power source.

A conventional technique is, for example, Japanese Patent Laid-Open No. Sho 60.
There is Japanese Patent No. 232446. An example of the above-described air conditioner will be described below with reference to the drawings.

FIG. 9 is a schematic configuration diagram of a conventional air conditioner. In FIG. 9, 1 is a compressor, 2 is a four-way valve, 3 is an indoor heat exchanger, 4 is a pressure reducing device, and 5 is an outdoor heat exchanger, and these are connected in an annular shape to form a refrigeration circuit.

Reference numeral 6 is an indoor blower, and 7 is an outdoor blower. A room temperature sensor 8 detects the indoor temperature. 9
Is a room temperature setting device for setting the room temperature.

An indoor control circuit 10 receives the output signals of the room temperature sensor 8 and the room temperature setting device 9.

Reference numeral 11 denotes a frequency command section, to which the frequency control signal output from the indoor control circuit 10 is input. Reference numeral 12 is a waveform storage device, which stores waveform patterns of two types of motor voltage-frequency characteristics during cooling and heating.

A cooling / heating detecting device 22 outputs a signal "0" during cooling and a signal "1" during heating.

Reference numeral 13 is a waveform generator, which takes in a cooling-time waveform pattern from the waveform storage device 12 when the output of the cooling / heating detecting device 22 is "0", and when the output of the cooling / heating detecting device 22 is "1". The heating-time waveform pattern is fetched from the waveform storage device 12, a waveform is generated, and a waveform signal is output.

Reference numeral 14 denotes a base drive circuit to which a waveform signal of a preset output of the motor voltage-frequency characteristic in each waveform pattern of the waveform generator 13 during cooling and heating is input.

Reference numeral 15 is an inverter main circuit, which takes in the waveform signal amplified by the base drive circuit 14,
The number of revolutions of the compressor 1 is controlled.

Reference numeral 16 is an AC / DC converter which converts the AC power supply 17 into a DC voltage. In addition, 20 is an indoor unit,
Reference numeral 21 is an outdoor unit. Reference numeral 19 denotes an inverter device, which includes a base drive circuit 14 and an inverter main circuit 15.

The operation of the air conditioner configured as described above will be described below.

During the operation of the air conditioner, the waveform generator 13 takes in the waveform pattern of the motor voltage-frequency characteristic during the cooling operation from the waveform storage device 12 during the cooling operation, and the motor voltage-frequency during the heating during the heating operation. The waveform pattern of the characteristic is taken in, a waveform is generated and input to the base drive circuit 14.

The input waveform is the base drive circuit 14
Is transmitted to and amplified by the inverter main circuit 15 to control the rotation speed of the compressor 1.

[0016]

However, in the above configuration, the inverter device 19 outputs only two types of inverter waveforms of the motor voltage-frequency characteristics during cooling and heating.

Therefore, when the load of the compressor 1 fluctuates due to changes in the load condition of the air conditioner during cooling or heating, the windings of the reactor connected in the AC / DC converter 16 for power factor improvement. The resistance increases as the temperature rises, the DC voltage drops, the motor voltage that is the output of the inverter device 19 decreases, the compressor 1 deviates from the optimum motor voltage-frequency characteristic, and the efficiency of the air conditioner deteriorates. .

In view of the above-mentioned problems, the present invention always provides a constant motor voltage to the compressor even when the DC voltage of the compressor decreases due to a change in the load condition of the air conditioner regardless of whether the air conditioner is cooling or heating. It is intended to provide an efficient air conditioner that maintains frequency characteristics.

[0019]

In order to achieve this object, an air conditioner of the present invention comprises an inverter device for generating a pseudo AC voltage and outputting an arbitrary frequency, and a compression controlled by the inverter device. And a discharge temperature detection device for detecting the discharge temperature of the compressor, and a discharge temperature-voltage conversion device for storing discharge temperature-DC voltage drop characteristics and outputting a DC voltage drop from the discharge temperature of the discharge temperature detection device. A voltage calculation device that calculates a current DC voltage from a DC voltage drop from the discharge temperature voltage conversion device; a waveform storage device that stores waveform patterns of different motor voltage-frequency characteristics; and the voltage calculation device. The waveform pattern of the motor voltage-frequency characteristic for the current DC voltage is fetched from the waveform storage device according to the DC voltage calculated in It is composed of a waveform generator for outputting to the serial inverter device.

Alternatively, an AC / DC converter for converting an AC voltage into a DC voltage, an inverter device for generating a pseudo AC voltage composed of the AC / DC converter and outputting an arbitrary frequency, and a rotation by the inverter device. A discharge controlled by a number of compressors, a discharge pressure detection device for detecting the discharge pressure of the compressor, a discharge pressure-DC voltage drop characteristic is stored, and a DC voltage drop is output from the discharge pressure of the discharge pressure detection device. A pressure-voltage converter, a voltage calculator that calculates the current DC voltage from the DC voltage drop from the discharge pressure-voltage converter, and a waveform storage device that stores waveform patterns of different motor voltage-frequency characteristics. A waveform pattern of a motor voltage-frequency characteristic with respect to the current DC voltage from the waveform storage device according to the DC voltage calculated by the voltage calculation device. Uptake, and a waveform generator that generates a waveform output to the inverter device.

[0021]

The present invention utilizes the fact that the discharge temperature and the discharge pressure are proportional to the drop of the DC voltage due to the reactor connected in the AC / DC converter for improving the power factor due to the above-mentioned configuration, The DC voltage drop due to the fluctuation of the load condition of the air conditioner is calculated from the discharge temperature and the discharge pressure detected by the discharge temperature detection device and the discharge pressure detection device, and the motor voltage-frequency of the output of the inverter device By changing the characteristics, a constant voltage-frequency characteristic is maintained for the compressor and a waveform signal is output, so an efficient air conditioner can be realized with a simple circuit configuration of waveform pattern switching. Becomes

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An air conditioner according to a first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an air conditioner in a first embodiment of the present invention. FIG. 2 shows the relationship between the discharge temperature and the DC voltage drop. Further, FIG. 3 shows the relationship between the frequency and the motor voltage of the inverter output with respect to the change of the DC voltage.

In FIG. 1, 1 is a compressor, 2 is a four-way valve,
3 is an indoor heat exchanger, 4 is a pressure reducing device, 5 is an outdoor heat exchanger,
6 is an indoor blower, 7 is an outdoor blower, 8 is a room temperature sensor, and 9 is a room temperature sensor.
Is a room temperature setting device, 10 is an indoor control circuit, 11 is a frequency control unit, 14 is a base drive circuit, 15 is an inverter main circuit, 20 is an indoor unit, and 19 is an inverter device. The above is the same as the conventional configuration of FIG. Therefore, detailed description thereof will be omitted.

Reference numeral 23 denotes a discharge temperature detecting device, which is used for the compressor 1.
The discharge temperature of is detected. The detected discharge temperature I is input to the discharge temperature / voltage converter 24, and the DC voltage drop P is calculated from the relationship between the discharge temperature and the DC voltage drop in FIG.
The DC voltage drop P is output to the voltage calculation device 25.

The voltage calculation device 25 calculates the current DC voltage from the DC voltage drop P according to (Equation 1).

[0027]

[Equation 1]

The calculated DC voltage α is applied to the waveform generator 26.
Is output to The waveform generator 26 requests the waveform storage device 27 for a waveform pattern to be output.

In the waveform storage device 27, as shown in FIG. 3, three motor voltage-frequency characteristic waveform patterns A, B,
Since C is stored, the signal to be output is determined based on the DC voltage α calculated by the voltage calculation device 25 and the operating frequency of the compressor 1.

For example, if the signal is α1, the waveform pattern A, if the signal is α2, the waveform pattern B, and if the signal is α3, the waveform pattern C is fetched from the waveform storage device 27, a waveform is generated, and the waveform signal is supplied to the base drive circuit 14. Output.

Regarding the air conditioner configured as described above, the discharge temperature detecting device 23, the discharge temperature voltage converting device 24, the voltage calculating device 25, the waveform generating device 26, and the waveform storing device 27 will be described below with reference to FIG. The operation will be described.

FIG. 4 is a flow chart showing the operation of this embodiment. The operation of the compressor 1 is started (step 1). The DC voltage drop P is calculated from the discharge temperature I of the compressor 1 detected by the discharge temperature detection device 23 using FIG. 2 (step 2). The DC voltage α at the time of the DC voltage drop P is calculated by the voltage calculation device 25 (step 3). Based on the DC voltage α and the frequency at which the compressor 1 is currently operating, it is determined which of the regions A, B and C in FIG. 3 is output and one of the signals A, B and C is output to the waveform generator 26 ( Step 5).

The signal taken into the waveform generator 26 is "α
It is determined whether it is 1 "(step 6). The signal is" α.
If it is 1 ", the waveform pattern" A "stored in the waveform storage device 27 is fetched (step 7).

If the signal is not "α1", the signal is "α1".
It is determined whether it is 2 "(step 8). The signal is" α.
If it is 2 ", the waveform pattern" B "stored in the waveform storage device 27 is fetched (step 9).

If the signal is not "α2", the signal "α3"
Therefore, the waveform pattern "C" stored in the waveform storage device 27 is loaded (step 10). A waveform signal is generated by the waveform pattern acquired in any one of step 7, step 9 and step 10 (step 11). A waveform signal is generated (step 12).

According to the above flow chart, the waveform signal output from the waveform generator 26 is the base drive circuit 14
Through the inverter main circuit 15. The inverter main circuit 15 amplifies the input waveform signal and outputs a three-phase inverter waveform to control the rotation speed of the compressor 1.

Thus, as shown in FIG. 3, the waveform patterns A, B and C and the motor voltage-frequency characteristics stored in the waveform storage device 27 are determined by the load of the compressor 1 depending on the operating state of the indoor unit 20. In order to correct the DC voltage due to the reactor inside the AC / DC converter 16 due to the fluctuation of the
The compressor operates with frequency characteristics.

As described above, according to the present embodiment, the fact that the discharge temperature is proportional to the drop in the DC voltage due to the reactor is utilized, and the DC voltage with respect to the change in the discharge temperature due to the change in the load condition of the air conditioner is utilized. By calculating the direct current voltage from the discharge pressure at the discharge temperature detected by the discharge temperature detection device 23 and changing the motor voltage-frequency characteristic of the output of the inverter device 19, the drop is kept constant with respect to the compressor 1. It is possible with a simple circuit configuration that outputs a waveform signal that maintains the motor voltage-frequency characteristics and switches the waveform pattern.

Further, since the discharge temperature detecting device 23 is already provided for controlling the system of the air conditioner, it can be used in common, and an efficient air conditioner can be easily realized.

The invention can be applied to any device (for example, a refrigerator, a vending machine, a showcase, etc.) in which the power factor is improved in the reactor by using other inverters.

As a result, the input current of the compressor 1 is reduced, the capacity and size of the inverter device 19 can be reduced, and the noise and vibration of the compressor 1 can be reduced.

Therefore, the efficiency of the air conditioner and the reduction of noise and vibration can be realized.

An air conditioner according to a second embodiment of the present invention will be described below with reference to the drawings.

FIG. 5 is a schematic configuration diagram of the air conditioner in the second embodiment of the present invention. FIG. 6 shows the relationship between the discharge pressure and the DC voltage drop. FIG. 7 shows the relationship between the frequency and the motor voltage of the output of the inverter device with respect to the change of the DC voltage.

In FIG. 5, 1 is a compressor, 2 is a four-way valve,
3 is an indoor heat exchanger, 4 is a pressure reducing device, 5 is an outdoor heat exchanger,
6 is an indoor blower, 7 is an outdoor blower, 8 is a room temperature sensor, and 9 is a room temperature sensor.
Is a room temperature setting device, 10 is an indoor control circuit, 11 is a frequency control unit, 14 is a base drive circuit, 15 is an inverter main circuit, 20 is an indoor unit, and 19 is an inverter device. The above is the same as the conventional configuration of FIG. Therefore, detailed description thereof will be omitted.

Reference numeral 28 is a discharge pressure detecting device, which is used for the compressor 1.
The discharge pressure of is detected. The detected discharge pressure I is input to the discharge pressure-voltage converter 29, and the DC voltage drop P is calculated from the relationship between the discharge pressure and the DC voltage drop shown in FIG.
The DC voltage drop P is output to the voltage calculation device 25.

The voltage calculation device 25 calculates the current DC voltage from the DC voltage drop P according to (Equation 1).

The calculated DC voltage α is applied to the waveform generator 26.
Is output to The waveform generator outputs the DC voltage P to the 26 waveform storage devices.

In the waveform storage device 27, as shown in FIG. 7, three motor voltage-frequency characteristic waveform patterns A, B, and
Since C is stored, the waveform pattern A is output if the signal output based on the DC voltage α calculated by the voltage calculation device 25 and the operating frequency of the compressor 1 is α1, and the waveform pattern B is output if the signal is α2. If it is the signal α3, the waveform pattern C is fetched from the waveform storage device 27, a waveform is generated, and the waveform signal is output to the base drive circuit 14.

Regarding the air conditioner configured as described above, the discharge pressure detecting device 28, the discharge pressure / voltage converting device 29, the voltage calculating device 25, the waveform generating device 26, and the waveform storing device 27 will be described below with reference to FIG. The operation will be described.

FIG. 8 is a flow chart showing the operation of the second embodiment of the present invention. The operation of the compressor 1 is started (step 1). The DC voltage drop P is calculated from the discharge pressure I of the compressor 1 detected by the discharge pressure detection device 28 using FIG. 6 (step 2). The DC voltage α at the time of the DC voltage drop P is calculated by the voltage calculation device 25 (step 3).
Based on the DC voltage α and the frequency at which the compressor 1 is currently operating, it is determined which of the regions A, B and C in FIG. 3 is output and one of the signals A, B and C is output to the waveform generator 26 ( Step 5).

The waveform generator 26 receives the signal "
It is determined whether it is α1 ”(step 6). The signal is“ α
If it is 1 ", the waveform pattern" A "stored in the waveform storage device 27 is fetched (step 7).

If the signal is not "α1", the signal is "α1".
It is determined whether it is 2 "(step 8). The signal is" α.
If it is 2 ", the waveform pattern" B "stored in the waveform storage device 27 is fetched (step 9).

If the signal is not "α2", the signal "α3"
Therefore, the waveform pattern "C" stored in the waveform storage device 27 is loaded (step 10). A waveform signal is generated by the waveform pattern acquired in any one of step 7, step 9 and step 10 (step 11). A waveform signal is generated (step 12).

The waveform signal output from the waveform generator 26 according to the above flow is transmitted to the inverter main circuit 15 through the base drive circuit 14. The inverter main circuit 15 amplifies the input waveform signal and outputs a three-phase inverter waveform to control the compressor 1.

As described above, as shown in FIG. 7, the waveform patterns A, B, C and the motor voltage-frequency characteristics stored in the waveform storage device 27 are the load of the compressor 1 depending on the operating state of the indoor unit 20. DC voltage drop due to the reactor in the AC / DC converter 16 due to the fluctuation of
By switching the waveform pattern of, the compressor 1 is operated with a corrected and constant motor voltage-frequency characteristic.

As described above, according to this embodiment, the fact that the discharge pressure is proportional to the drop in the DC voltage due to the reactor is used to determine the drop in the DC voltage due to the change in the load condition of the air conditioner as the discharge pressure. The DC voltage is calculated from the discharge pressure detected by the detection device 28, and the motor voltage-frequency characteristic of the output of the inverter device 19 is changed to maintain a constant motor voltage-frequency characteristic for the compressor 1. In order to output the waveform signal, a simple circuit for switching the waveform pattern can be configured with one sensor of the discharge pressure detection device 28, and an efficient air conditioner can be realized.

The present invention can be applied to any device in which the power factor is improved in the reactor by using other inverters.

As a result, the input current of the compressor 1 is reduced, the capacity and size of the inverter device 19 can be reduced, and the noise and vibration of the compressor 1 can be reduced.

Therefore, the efficiency of the air conditioner and the reduction of noise and vibration can be realized.

[0061]

As described above, the present invention detects an inverter device for generating a pseudo AC voltage and outputting an arbitrary frequency, a compressor whose rotation speed is controlled by the inverter device, and a discharge temperature of the compressor. And a discharge temperature detecting device for storing a discharge temperature-DC voltage drop characteristic and outputting a DC voltage drop from the discharge temperature of the discharge temperature detecting device, and a DC voltage from the discharge temperature voltage converting device. A voltage calculation device that calculates the current DC voltage from the drop,
A waveform storage device that stores waveform patterns of different motor voltage-frequency characteristics, and a motor voltage-frequency characteristic of the current DC voltage from the waveform storage device according to the DC voltage calculated by the voltage calculation device. The waveform generator takes in a waveform pattern, generates a waveform, and outputs the waveform to the inverter device.

Alternatively, an AC / DC converter for converting an AC voltage into a DC voltage, an inverter device for generating a pseudo AC voltage composed of the AC / DC converter and outputting an arbitrary frequency, and a rotation by the inverter device. A discharge controlled by a number of compressors, a discharge pressure detection device that detects the discharge pressure of the inverter device, a discharge pressure-DC voltage drop characteristic is stored, and a DC voltage drop is output from the discharge pressure of the discharge pressure detection device. A pressure-voltage converter, a voltage calculator for calculating the current DC voltage from the DC voltage drop from the discharge pressure-voltage converter, and different motor voltages-
A waveform storage device that stores a waveform pattern of a frequency characteristic, and a waveform pattern of a motor voltage-frequency characteristic for the current DC voltage from the waveform storage device is fetched from the waveform storage device according to the DC voltage calculated by the voltage calculation device. Is generated and output to the inverter device.

With the above configuration, the fact that the discharge temperature and the DC voltage are proportional to the drop of the DC voltage due to the reactor is used to reduce the drop of the DC voltage with respect to the increase of the discharge temperature due to the change of the load condition of the air conditioner. , A discharge temperature detection device, and a discharge pressure detected by the discharge pressure detection device, a DC voltage is calculated from the discharge pressure, and the motor voltage-frequency characteristic of the output of the inverter device is changed to keep the compressor constant. Since the voltage-frequency characteristic is maintained and the waveform signal is output, an efficient air conditioner can be realized with a simple circuit configuration of switching the waveform pattern.

Further, the present invention can be applied to any device (for example, a refrigerator, a vending machine, a showcase, etc.) in which the power factor is improved in the reactor by using other inverters. Its practical effect is enormous.

[Brief description of drawings]

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

FIG. 2 is a characteristic diagram showing a relationship between a discharge temperature and a DC voltage drop in the example.

FIG. 3 shows respective motor voltages of waveform patterns stored in a waveform storage device in the air conditioner of the embodiment.
Frequency characteristic chart

FIG. 4 is a flowchart showing the operation of the air conditioner of the same embodiment.

FIG. 5 is a schematic configuration diagram of an air conditioner according to a second embodiment of the present invention.

FIG. 6 is a characteristic diagram showing a relationship between discharge pressure and DC voltage drop in the example.

FIG. 7 shows respective motor voltages of waveform patterns stored in a waveform storage device in the air conditioning apparatus of the embodiment.
Frequency characteristic chart

FIG. 8 is a flowchart showing the operation of the air conditioner of the same embodiment.

FIG. 9 is a schematic configuration diagram of a conventional air conditioner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 16 AC / DC converter 19 Inverter device 23 Discharge temperature detection device 24 Discharge temperature voltage converter 25 Voltage calculation device 26 Waveform generator 27 Waveform storage device 28 Discharge pressure detection device 29 Discharge pressure voltage converter

Claims (2)

[Claims] 1. An inverter device that generates a pseudo AC voltage and outputs an arbitrary frequency, a compressor whose rotation speed is controlled by the inverter device, a discharge temperature detection device that detects a discharge temperature of the compressor, and a discharge device. A discharge temperature / voltage conversion device that stores a temperature-DC voltage drop characteristic and outputs a DC voltage drop from the discharge temperature of the discharge temperature detection device, and a current DC voltage is calculated from the DC voltage drop from the discharge temperature / voltage conversion device. According to a DC voltage calculated by the voltage calculation device, a waveform storage device that stores waveform patterns of different motor voltage-frequency characteristics, and a DC voltage calculated by the voltage calculation device.
An air conditioner comprising: a waveform generator that takes in a waveform pattern of a motor voltage-frequency characteristic for a current DC voltage from the waveform storage device, generates a waveform, and outputs the waveform to the inverter device. 2. An AC / DC converter for converting an AC voltage into a DC voltage, an inverter device for generating a pseudo AC voltage composed of the AC / DC converter and outputting an arbitrary frequency, and a rotation by the inverter device. A discharge controlled by a number of compressors, a discharge pressure detection device for detecting the discharge pressure of the compressor, a discharge pressure-DC voltage drop characteristic is stored, and a DC voltage drop is output from the discharge pressure of the discharge pressure detection device. A pressure-voltage converter, a voltage calculator that calculates the current DC voltage from the DC voltage drop from the discharge pressure-voltage converter, and a waveform storage device that stores waveform patterns of different motor voltage-frequency characteristics. , A waveform pattern of a motor voltage-frequency characteristic for the current DC voltage is obtained from the waveform storage device according to the DC voltage calculated by the voltage calculation device. And a waveform generator that generates a waveform and outputs the waveform to the inverter device.