JP2543153B2 - Air conditioner - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner including an inverter device that controls the rotation speed of a compressor.

2. Description of the Related Art In recent years, many air conditioners have been used in which capacity control is performed by increasing / decreasing the rotational speed of a compressor by using an inverter device that makes the frequency of a power supply variable. As a conventional technique, there is, for example, JP-A-60-232446.

An example of the above-described air conditioner will be described below with reference to the drawings.

FIG. 5 is a schematic configuration diagram of a conventional air conditioner. In FIG. 5, 1 is a compressor, 2 is a four-way valve, 3 is an indoor heat exchanger, 4 is a decompression device, 5 is an outdoor heat exchanger, and these are connected in a ring to form a refrigeration circuit. . 6 is an indoor blower, and 7 is an outdoor blower. A room temperature sensor 8 detects the room temperature. A room temperature setting device 9 sets the room temperature. Reference numeral 10 is a control circuit of the indoor unit, to which the output signals of the room temperature sensor 8 and the room temperature setting device 9 are input. 11 is a frequency command section, which is a control circuit for the indoor unit
The frequency control signal of 10 outputs is input. A waveform storage device 12 stores waveform patterns of two types of voltage-frequency characteristics during cooling and heating. A cooling / heating detection device 23 outputs a signal "0" during cooling and a signal "1" during heating. Reference numeral 13 is a waveform generator. If the output of the cooling / heating detecting device 23 is "0", a waveform pattern is taken from the waveform storage device 12 during cooling, and the output of the cooling / heating detecting device 23 is "1". If so, 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 is a base drive circuit,
The waveform signal of the preset output of the voltage-frequency characteristic of each waveform pattern during cooling and heating of 13 is input.
Reference numeral 15 is an inverter main circuit, and the base drive circuit
The waveform signal amplified by 14 is taken in and the compressor 1
Control. 16 is an indoor unit and 17 is an outdoor unit A. Reference numeral 18 denotes an inverter device, which includes the base drive circuit 14 and the inverter main circuit 15.

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

During the operation of the air conditioner, the waveform generator 13 takes in the waveform pattern of the voltage-frequency characteristic during cooling from the waveform storage device 12 during the cooling operation, and acquires the waveform pattern of the voltage-frequency characteristic during heating during the heating operation. To generate a waveform and input it to the base drive circuit 14. The input waveform is transmitted to the inverter main circuit 15 through the base drive circuit 10 and is amplified to control the compressor 1.

However, in the above-mentioned configuration, the inverter device 18 outputs only the inverter waveform having two types of voltage-frequency characteristics during cooling and heating. Therefore, the compressor 1 deviates from the optimum voltage-frequency characteristic due to a change in the load state of the air conditioner during cooling or heating, and the efficiency of the air conditioner including the efficiency of the compressor deteriorates. I had a problem.

In view of the above problems, the present invention constantly compresses by changing the voltage-frequency characteristic of the output of the inverter device when the load of the compressor increases or decreases due to a change in the load state of the air conditioner during cooling or heating. Optimum voltage for machine −
It is intended to provide an efficient air conditioner that maintains frequency characteristics.

Means for Solving the Problems In order to solve the above problems, the air conditioner of the present invention is a compressor whose rotation speed is controlled by an inverter device,
A rotation speed detection device that detects a change in the rotation speed due to the load of the compressor with respect to the rotation speed controlled by the inverter device, and a waveform storage device that stores waveform patterns of different voltage-frequency characteristics, It comprises a waveform generator that takes in a waveform pattern of an optimum voltage-frequency characteristic from the waveform storage device in response to a signal of a change in the number of revolutions due to the load of the number of revolutions detecting device to generate and output a waveform.

Effect of the Invention With the above-described configuration, the rotation speed detection device of the present invention detects a change in the rotation speed due to an increase or decrease in the load of the compressor with respect to the rotation speed controlled by the inverter device, and the compressor is detected by the change in the load state of the air conditioner. When the load increases or decreases, the signal from the rotation speed detector causes the waveform generator to capture the output of the waveform storage device that stores the waveform pattern of the optimum voltage-frequency characteristic from the waveform storage device to generate the waveform signal. Output. The output waveform signal is transmitted to the main inverter circuit via the base drive circuit and amplified to become the output of the inverter device. Even if the load on the compressor increases or decreases, the output of the inverter device always maintains the optimum voltage-frequency characteristic. . Therefore, an efficient air conditioner can be realized.

Embodiment An air conditioner according to an 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 one embodiment of the present invention. In FIG. 1, 1 is a compressor, 2 is a four-way valve, 3 is an indoor blower, 7 is an outdoor blower, 8 is a room temperature sensor, 9 is a room temperature setting device, 10 is an indoor control circuit, 11 is a frequency command section, and 14 is a base. The drive circuit, 15 is an inverter main circuit, 16 is an indoor unit, and 18 is an inverter device. Since the following is the same as the conventional configuration diagram of FIG. 5, detailed description thereof will be omitted. Reference numeral 19 denotes a rotation speed detection device, which stores three zones A, B, and C divided by rotation speed difference-frequency characteristics as shown in FIG. 2, and the inverter device 18 is installed in the compressor 1. On the other hand, when the rotation speed is controlled at a constant value, the torque of the compressor 1 increases as the load increases, and the rotation speed decreases due to the change in the load. The rotation speed difference and the frequency command at that time are used. It is determined which of the zones A, B and C the value is in and the respective signals A, B and C are output. Reference numeral 20 denotes a waveform storage device which stores three waveform patterns A ', B', C'having three voltage-frequency characteristics as shown in FIG. Reference numeral 21 is a waveform generator, which outputs a waveform pattern A'if the output of the rotation speed detecting device 19 is a signal A, a waveform pattern B'if a signal B, and a waveform pattern C'if a signal C.
Captured from 20 to generate a waveform and output a waveform signal to the base drive circuit 14. 22 is an outdoor unit. Regarding the air conditioner configured as described above, the first
The operation will be described with reference to FIG. 2, FIG. 3, FIG.

FIG. 4 is a flowchart showing the operation of the waveform generator 21. First, the operation of the waveform generator 21 will be described with reference to FIG. When the operation of the compressor 1 is started in step 1, the compressor causes the frequency command unit 11 to operate in step 2.
When the frequency output from is reached, the rotation speed detection device 19
Takes in the number of rotations. Next, in step 3, if the difference between the number of revolutions taken in by the revolution number detecting device 19 and the previously detected number of revolutions is positive, the state is down one rank, that is, if the current state is B, the rank is A. The waveform pattern "A" stored in the waveform storage device 20 is taken in, and when the power is turned on, it starts from rank B. If there is no difference between the number of revolutions taken in by the number-of-revolutions detecting device 19 and the number of revolutions previously detected in step 5, the current state is maintained. That is, if the current state is B, the rank becomes B and the process proceeds to step 6 to take in the waveform pattern "B" stored in the waveform storage device 20.
If the difference between the number of revolutions taken in step 5 and the number of revolutions detected last time is negative, it is in the state of one rank up, that is, if the present condition is B, it becomes C rank, and the process proceeds to step 7 and the waveform storage device 20 stores it. Take in the waveform pattern “C”. A waveform signal is generated in step 8 and a waveform signal is generated in step 9 according to the waveform pattern fetched in step 4 or steps 6 and 7. Finally, in step 10, the rotational speed detected this time by the rotational speed detection device 19 is set to the previous rotational speed.

The waveform signal output from the waveform generator 21 by the above flow is transmitted to the base drive main circuit 15. The inverter main circuit 15 amplifies the input waveform signal and outputs a three-phase inverter waveform to control the compressor 1. As shown in FIG. 3, the waveform storage device 20
The voltage-frequency characteristics of the waveform patterns A ', B', C'stored by the compressor 1 depend on the operating state of the indoor unit 16.
An optimum voltage-frequency characteristic is obtained due to the output voltage drop of the inverter device 18 due to the increase or decrease of the load. Therefore, the compressor 1 is always operated with the optimum voltage-frequency characteristic regardless of the load increase / decrease. Further, in the present embodiment, the voltage-frequency characteristics are designated and controlled in three stages, but by employing a plurality of stages, more detailed control can be easily realized.

As described above, according to the present embodiment, even if the pressure of the cooling system fluctuates depending on the operating state of the indoor unit 16, the rotation speed from the rotation speed detection device 19 corresponds to the load from the waveform storage device 20. Since the waveform pattern of the optimum voltage-frequency characteristic is taken in and the waveform is generated and output, the compressor 1 is always operated with the optimum voltage-frequency characteristic regardless of the increase or decrease of the load. As a result, the input current of the compressor 1 is reduced, the capacity and size of the inverter device 18 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.

EFFECTS OF THE INVENTION As described above, the present invention provides a compressor whose rotation speed is controlled by an inverter device, and a rotation speed detection device which detects a change in rotation speed due to a load of the compressor with respect to a rotation speed controlled by the inverter device. A device, a waveform storage device that stores waveform patterns of different voltage-frequency characteristics, and an optimum voltage-frequency characteristic from the waveform storage device according to a signal of a change in rotation speed due to a load of the rotation speed detection device. By providing a waveform generator that takes in a waveform pattern and generates and outputs a waveform, even if the load on the compressor increases or decreases depending on the operating state of the indoor unit, the load can be reduced by directly detecting the rotation speed of the compressor. Fluctuations can be detected accurately, and the output of the inverter device always maintains the optimum voltage-frequency characteristics for the compressor, so it is very efficient and has low noise and vibration. It is possible to realize a summing device, and its practical effect is great.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an air conditioner in one embodiment of the present invention, FIG. 2 is a rotation speed-frequency characteristic diagram stored in the rotation speed detection device of FIG. 1, and FIG. 3 is FIG. FIG. 4 is a flowchart showing the operation of the waveform generator of FIG. 1, and FIG. 5 is a schematic configuration diagram of a conventional air conditioner. Is. 1 ... Compressor, 19 ... Rotation speed detection device, 20 ... Waveform storage device, 21 ... Waveform generator.

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Claims (1)

(57) [Claims] 1. A compressor whose rotation speed is controlled by an inverter device, and a rotation speed detection device which detects a change in the rotation speed due to the load of the compressor with respect to the rotation speed controlled by the inverter device. A frequency storage device that stores a waveform pattern of voltage-frequency characteristics, and a waveform pattern of an optimum voltage-frequency characteristic is captured from the waveform storage device by a signal of a change in rotation speed due to a load of the rotation speed detection device, An air conditioner comprising: a waveform generator that generates and outputs.