JPH035653A - Control device for split type air conditioner - Google Patents

Abstract

PURPOSE:To make the responsiveness to control always appropriate by detecting the distance between an outdoor unit and an indoor unit from leak currents flowing through interwire stray capacitances and by altering according to the results the starting time of the compressor. CONSTITUTION:A wiring distance-calculating means 43 calculates the distance L of electric wires 31-33 which are laid between an indoor unit 10 and an outdoor unit 20 on the basis of the values of leak currents which flow through interwire stray capacitances generated according to the distance L and which a leak current-detective means 42 detects. And an outdoor unit control device 21 alters the starting time of a compressor C on the basis of the distance L of the laying of pipes thus calculates. As a result, the starting time of the compressor can be made always appropriate with the distance of the piping taken into consideration and scuffing in the compressor due to inadequate reflux of the lubricating oil can be avoided.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention relates to a control device for a split type air conditioner, more specifically, an indoor unit including an indoor heat exchanger, a compressor, and an outdoor heat exchanger. Split type air is divided into an outdoor unit including an exchanger and an indoor unit controller, and the compressor included in the outdoor unit is controlled by the indoor unit controller provided in the indoor unit via the outdoor unit controller provided in the outdoor unit. This invention relates to a control device for a harmonizer.

(Prior art) The control device for the above-mentioned split type air conditioner has a fourth
It is configured as illustrated in the figure.

The air conditioner shown in FIG. 4 consists of an indoor unit 10 and an outdoor unit 20. Both units are connected via piping in the refrigeration cycle, and via wiring 31, 32, 33 in the electric circuit. connected. The indoor unit 10 includes an indoor heat exchanger and an indoor fan (not shown), and is equipped with an indoor unit controller 11 that controls the indoor fan and the outdoor unit 20. The outdoor unit 20 includes a compressor C, a compressor motor CM that drives it, a frequency converter 22 that drives the compressor motor CM at various frequencies,
Furthermore, in addition to the outdoor heat exchanger, outdoor fan, etc., an outdoor unit controller 21 is included that controls the output frequency of the frequency converter 22, the operation of the outdoor fan, etc. based on control signals from the indoor unit 10. Note that the frequency converter 22 may be a DC circuit-interposed type consisting of a rectifier and an inverter, or may be a cycloconverter without a DC circuit as the case may be.

The wires 31 and 32 are power wires, and are connected to the indoor unit 10.
It is connected to an AC power source (not shown) on the side, and is used to supply operating power to the indoor unit 10 and outdoor unit 20, and also to send control signals between the two units. Indoor unit 1 is connected between both wirings 31 and 32.
On the 0 side, in addition to the power supply circuit of the indoor unit controller 11, a resistor 12, a cyrisk 13, and a light emitting diode 14 are installed.
, and a series circuit of a resistor 15 and a series circuit of a resistor 16 and a light emitting diode 17 are connected in parallel. Note that the thyristor 13 and the light emitting diode 13 are arranged in opposite directions. A diode 18 is connected to the light emitting diode 17 in antiparallel. light emitting diode 1
Reference numeral 7 constitutes a photocoupler PCI together with a phototransistor (not shown) provided in the indoor unit controller 11. Further, a phototransistor 19 is combined with the light emitting diode 14, and both constitute a photocoupler PC2. Furthermore, between both wirings 31 and 32, on the outdoor unit 20 side, in addition to the frequency converter 22,
A series circuit of a thyristor 23, a resistor 24, a resistor 25, and a light emitting diode 26 is connected. Thyristor 2
3 is arranged in the opposite direction to the cyrisk 13. The light emitting diode 26 is arranged in the opposite direction to the thyristor 23, and a phototransistor 27 is combined with the light emitting diode 26.
It constitutes B. The intermediate wiring 33 is a signal line,
A connection point A between the thyristor 13 and the light emitting diode 14 and a connection point B between the resistors 24 and 25 are connected.

Photocoupler PCI is connected to wiring 31.32 AC m
It conducts every positive half wave of s, and generates a "1" signal used as a synchronization signal in the indoor unit controller 11 in synchronization with the power supply frequency.

The control signal is sent from the indoor unit controller 11 to the outdoor unit controller 21, that is, the serial forward transfer signal is sent by controlling the thyristor 13 on and off by the indoor unit controller 11. Thyristor 1
3 is turned on, current flows to the light emitting diode 26 through the resistor 12, thyristor 13, wiring 33, and resistor 25 during the positive half-wave period of the AC power supply, and the light emitting diode 26 emits light. It connects the outdoor unit 2 to the outdoor unit controller 21 via the phototransistor 27 of the photocoupler PCB.
It is transferred as a control signal of 0. Outdoor unit controller 2
1 to the indoor unit controller 11, the outdoor unit 20
Sending of a response signal including data on the operating status of the thyristor 23, that is, sending of a serial reverse transfer signal, is performed by controlling the thyristor 23 on and off by the outdoor unit controller 21. When the thyristor 23 is controlled to be turned on, a current flows through the electrical path of the resistor 15, the light emitting diode 14, the wiring 33, the resistor 24, and the thyristor 23 during the negative half-wave period of the AC power supply, and the light emitting diode 26 emits light. As a result, the signal is transferred to the indoor unit controller 11 as a response signal from the outdoor unit 20 via one phototransistor of the photocoupler PC2. The operation of the indoor unit controller 11 and the outdoor unit controller 21 is controlled by the photocoupler PCI.
This is done in synchronization with the synchronization signal from.

(Problems to be Solved by the Invention) In the control device for a split-type air conditioner with a grooved bottom as shown in FIG.
When the wiring distance between the refrigeration cycle and the refrigeration cycle becomes long, a delay occurs in the movement of the refrigerant within the refrigeration cycle. Therefore, when starting the compressor C, that is, the compressor motor CM, the starting time of the compressor motor CM must be shortened in consideration of the delay in movement of the refrigerant. However, on the contrary, there are cases in which the piping length fiL is actually short even though the starting time of the compressor motor CM has been shortened in advance in consideration of the delay in the movement of the refrigerant. In this case, even though it is possible to shorten the startup time of the compressor motor CM and perform control with better responsiveness, control with poor responsiveness is performed.

Furthermore, if the piping distance is long, it will take a long time for the lubricating oil that flows out from the compressor C into the piping mixed with the refrigerant due to the operation of the compressor C to circulate within the refrigeration cycle and return to the compressor C again. It takes a long time, so
There is a problem in that when starting up the compressor C, there is a lack of lubricating oil, which may cause so-called "galling".

The present invention has been made in consideration of the above circumstances, and is a split type air conditioner that can always automatically set an appropriate startup time for the compressor regardless of the piping distance between the indoor unit and the outdoor unit. The purpose is to provide a control device for.

[Structure of the invention]

(Means for Solving the Problems) The present invention is arranged separately into an indoor unit including an indoor heat exchanger and an outdoor unit including a compressor and an outdoor heat exchanger, and is installed in the indoor unit according to the air conditioning load. In a control device for a split type air conditioner, the speed of a compressor included in an outdoor unit is controlled by an indoor unit controller provided in an outdoor unit via an outdoor unit controller provided in an outdoor unit. leakage current detection means for detecting a leakage current flowing through stray capacitance between wirings that occurs depending on the distance between the indoor unit and the outdoor unit in a control signal circuit through which a control signal transmitted to the indoor unit should flow; piping distance calculation means for calculating the distance between the indoor unit and the outdoor unit based on the leakage current detected by the means; and changing the compressor startup time according to the distance calculated by the piping distance calculation means. The invention is characterized by comprising a means for doing so.

(Function) The present invention focuses on the fact that stray capacitance between wires is approximately proportional to the piping distance between both units, and automatically measures the piping distance by detecting leakage current flowing through the stray capacitance. Detecting leakage current is relatively easy;
On the other hand, considering that the structure of the wiring installed between both units is also known in advance, it is easy to calculate the piping distance based on the detected current value. By changing the compressor startup time based on the piping distance obtained by the piping distance calculation means, the compressor startup time is always appropriate considering the piping distance, and control responsiveness is always appropriate depending on the piping distance. This makes it possible to avoid compressor "galling" caused by a lack of recirculated lubricating oil.

(Example) FIG. 1 shows an embodiment of the present invention.

Here, the same parts as in FIG. 4 are given the same reference numerals.

In the circuit of FIG. 1, a light emitting diode 40 is connected in series with the light emitting diode 26 of the photocoupler PCB. The light emitting diode 40 and the phototransistor 41 constitute a photocoupler PC4. Based on the voltage between the wiring 31 and the wiring 32, the light emitting diode 40 has a
A leakage current ■8□ always flows from the wiring 31 through the stray capacitance C11 wiring 33 existing between the wiring 31 and the wiring 33, the resistor 25, the light emitting diode 26, and the light emitting diode 40. This leakage current ■5□ is detected by a leakage current detection circuit 42 via a phototransistor 41 optically coupled to a light emitting diode 40,
It leads to piping distance calculation means 43. Note that the light emitting diode 4
0 and the phototransistor 41 constitute a photocoupler PC4.

The piping distance calculation means 43 calculates the amount based on the capacitance per unit length according to the structure of the wiring which is known in advance, the resistance value of the resistor in the current circuit (in this case, the resistor 25), and the frequency of the AC power supply. Calculate the piping distance from the leak current IS. This calculation is performed as follows.

The piping distance is L1, and the line stray capacitance per unit length of 33 is C (pF/m), and the line 31 is
．． If the power supply voltage applied between 32 and 32 is E (V) and the power supply frequency is f (Hz), then the leakage current 15□ will be , if this is ignored, it becomes l81-2πfCEL(A). Therefore, the piping distance can be calculated as L = I, t/ (2πf CE) (m).

For example, if the stray capacitance C per unit length of the wiring 31, 32, 33 is 200 (pF/m), the wiring 3
The voltage E of the power supply applied between 1.32 and 220 (V)
, the power supply frequency f is 60 (Hz), L-0,5Xl0-
2 ÷ (2X w X80X200 Xl0-”' X22
0) 30.2 (m), and it can be determined that the piping distance is approximately 30 m.

The outdoor unit controller 21 selects the most appropriate compressor C according to the piping distance calculated by the piping distance calculation means 43.
Set the startup time.

Note that there may be various starting patterns at the time of starting the compressor, that is, transition curves of the rotational speed Hz of the compressor C with respect to time t at the time of starting. Figures 2 and 3 are
This is a different example.

FIG. 2 shows a system in which the rotational speed Hz is stepped up at predetermined time intervals, where the solid line shows the case where the piping pressure ML is long, and the broken line shows the case where the piping distance is short. When the piping distance is short, as shown by the broken line, the startup is completed in a shorter time t11, and when the piping pressure ML is long, as shown by the solid line, the startup is completed in a longer time t12. In any case, time tII
The time t1° may be determined approximately in proportion to the piping distance.

Fig. 3 shows a method in which the rotational speed Hz is accelerated linearly, that is, at a constant acceleration, to the final speed commanded by the indoor unit 10 force control signal, and the solid line indicates the case where the pipe pressure IL is long. The broken lines indicate the case where the piping distance is short.

In this case as well, if the piping distance is short as shown by the broken line, the startup will be completed in a shorter time t2□, and if the piping distance is long as shown by the solid line, the startup will be completed in the longer time t22. There is.

Such a starting pattern can be easily realized by using the frequency conversion device 22.

In the above embodiment, the leak current detection circuit 42 is provided on the outdoor unit 20 side, but the leak current detection circuit may be provided on the indoor unit 10 side depending on the transmitting/receiving circuit configuration. In that case, the operation of the compressor C (compressor motor CM) can be controlled from the indoor unit 10 side.

Further, in the above embodiment, the leakage current ■sl flowing through the stray capacitance CI between the wirings 31 and 33 is detected, but a method may be adopted in which the leakage current flowing through the stray capacitance C2 between the wirings 32 and 33 is detected. You can also do it.

By changing the startup time according to the piping distance as described above, it is possible to exhibit good responsiveness that matches the movement of the refrigerant and lubricating oil in the refrigeration cycle. In addition, the above change in startup time ensures that even if the piping distance changes, the lubricating oil flowing out from compressor C always flows back to compressor C and acts in time for the startup operation of compressor C, so the piping distance can be changed. Compressor start-up operation without "galling" can be achieved even for long periods.

[Effects of the Invention] According to the present invention, by changing the compressor startup time based on the piping distance ML obtained by the piping distance calculation means, it is possible to always achieve an appropriate compressor startup time in consideration of the piping distance. It is possible to always exhibit appropriate control responsiveness depending on the piping distance, and to achieve compressor start-up operation without "galling" even when the piping distance is long.

vessel, 13.23...thyristor, 14,26. '40
...Light emitting diode, 19,27.41...Phototransistor, 20...Outdoor unit, 21...Outdoor unit controller, 22...Frequency converter, 31.
32゜33...Wiring, 42...Leak current detection means, 43...Piping distance calculation means, Cl, C2...7jX free capacitance between wiring, I, leakage current, CM
...Compressor motor, C...Compressor, P
CI, PC2PC3, PO2...Hotokabura.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing one embodiment of the present invention, Figs. 2 and 3 are graphs showing different examples of compressor starting patterns used in the device of Fig. 1, and Fig. 4 is a conventional split type air compressor. It is a circuit diagram of a control device of a harmonizer.

Claims (1)

[Claims] The indoor unit is divided into an indoor unit including an indoor heat exchanger and an outdoor unit including a compressor and an outdoor heat exchanger. In a control device for a split type air conditioner in which a compressor included in the outdoor unit is controlled via an outdoor unit controller that is connected to the outdoor unit controller, a control signal transmitted from the indoor unit controller to the outdoor unit controller should flow. A leakage current detection means for detecting a leakage current flowing through a stray capacitance between wirings that occurs depending on the distance between the indoor unit and the outdoor unit in the control signal circuit, and a leakage current detected by the leakage current detection means. A piping distance calculation means for calculating the distance between the indoor unit and the outdoor unit based on the piping distance calculation means, and a means for changing the startup time of the compressor according to the distance calculated by the piping distance calculation means. A control device for a split-type air conditioner.