JP2007064561A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner which eliminates the need to use a step-down transformer by having a three-phase neutral-point transformer, and which is usable even in buildings with a three-phase 400 V power supply in Japan without using parts particularly resistant to voltage or providing insulation reinforcement or the like to deal with high voltages. <P>SOLUTION: The air conditioner includes a three-phase neutral-point transformer 4 having a neutral phase N connected to a three-phase 400 V AC power supply 2 and outputting the neutral point of the three-phase AC power supply 2. The air conditioner includes a means for supplying a small-power electric device 6 with electric power between a neutral phase N outputted from the three-phase neutral-point transformer 4 and either phase of the three-phase AC power supply 2, and a means for driving a compressor 53 by supplying the compressor with electric power from the three-phase AC power supply 2 via the three-phase neutral-point transformer 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an air conditioner.

  Currently in Japan, a three-phase 200V power supply is generally used in buildings that consume large amounts of power, such as buildings. However, in rare cases, a building equipped with equipment that consumes a large amount of power, such as an elevator, may use a three-phase 400V as a power source instead of a three-phase 200V. On the other hand, in Europe, as in Japan, both three-phase 200V or 400V power supplies are used. In Europe, a three-phase 400V power supply is used in a wider range than Japan.

  For this reason, air conditioners that use three-phase 200V as a power source are generally lined up for use in Japan, and air conditioners that use three-phase 200V and three-phase 400V as power sources for overseas markets such as Europe. Is lineup. However, in an air conditioner that uses a three-phase 200V power supply and an air conditioner that uses a three-phase 400V power supply, the electrical components that make up the air conditioner are manufactured in accordance with the respective power supply voltages. Therefore, it is difficult to manufacture an air conditioner that can handle both power sources using the same electrical component.

Here, in the case of a three-phase 400 V power supply in Europe, a three-phase four-wire system having a neutral phase in addition to a three-phase power line is standardized (see Patent Document 1). For this reason, the air conditioner corresponding to the three-phase 400V power supply uses an AC single-phase 200V between one phase of the three-phase power supply and the neutral phase for low-power electric parts such as a control circuit, a fan motor, and an electric valve. By using it, it is possible to use the same parts as those provided in an air conditioner that uses the same three-phase 200V as the power source used in Japan. That is, these low-power electric components can use components corresponding to single-phase 200V without using expensive high-voltage components corresponding to a three-phase 400V power source.
JP-A-6-319293

  However, in a building using a three-phase 400V power source in Japan, the above-described neutral phase terminals are rarely provided. For this reason, when installing an air conditioner that uses a three-phase 200V power source in a three-phase 400V facility in Japan, the three-phase 400V power source is stepped down to a three-phase 200V by a step-down transformer. I was trying. According to this method, the air conditioner can use an air conditioner that uses a three-phase 200V power supply, which is a general product for use in Japan, without changing the design of the air conditioner at all. It can correspond to a three-phase 400V power supply.

  However, an air conditioner used in a building that uses a three-phase 400 V power source has a large capacity and a large capacity, and its current capacity requires about several tens of A. Therefore, a transformer that steps down from 400 V to 200 V requires a very large capacity, is large in size, and is heavier than the air conditioner body in weight, exceeding 200 kg. Therefore, for example, the step-down transformer must be installed in the vicinity of the outdoor unit of the air conditioner, or the installation location of the step-down transformer is limited, for example, it is difficult to install in a building with a load resistance on the roof. In many cases, it is necessary to take measures such as waterproofing, electric shock prevention and leakage prevention, so that the step-down transformer itself becomes expensive. Therefore, there are various difficulties in using an air conditioner that uses a three-phase 200V power source for a three-phase 400V facility using the above-described step-down transformer.

  The present invention has been made in order to solve the above-mentioned problems, and the object of the present invention is to provide a three-phase neutral point transformer, so that it is not necessary to use a step-down transformer. It is an object to provide an air conditioner that can be used even in buildings that use a three-phase 400 V power source in Japan without using or reinforcing insulation for high voltage.

  According to an embodiment of the present invention, in an air conditioner, a three-phase neutral point transformer having a neutral phase connected to a three-phase 400 V AC power source and outputting a neutral point of the three-phase AC power source is provided. Means for supplying power between a neutral phase and one of the phases of the three-phase AC power source to a low-power electric device output from the three-phase neutral point transformer, and the three-phase neutral point transformer And means for supplying power from the three-phase AC power source to the compressor and driving the compressor.

  According to the present invention, by including a three-phase neutral point transformer, there is no need to use a step-down transformer, and there is no need to use a part with a particularly high withstand voltage or to provide insulation reinforcement for high voltage. It is possible to provide an air conditioner that can be used in buildings that use a three-phase 400 V power source in Japan.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
As shown in FIG. 1, an air conditioner 1 according to an embodiment of the present invention is connected to a three-phase 400V AC power source 2, and an outdoor unit 3 to which a power source voltage is supplied from the three-phase AC power source 2 is driven. Prepare. In the outdoor unit 3, a three-phase neutral point transformer 4 including an A / C terminal block 31 and a neutral output terminal Na for connection to a neutral phase output terminal N of the A / C terminal block 31 is provided. Yes. Normally, the A / C terminal block 31 is an input (power supply side) terminal on the left side and an output (load) side terminal on the right side. However, for simplicity of connection, the neutral output terminal Na of the three-phase neutral point transformer 4 is used. Is connected to the neutral output terminal N of the A / C terminal block 31.

  Further, in the outdoor unit 3, the compressor drive unit 5 that is driven by the supply voltage supplied from the three-phase AC power source 2 and the neutral output that is output from the three-phase neutral point transformer 4 are supplied to the A / C terminal block 31. A low-power electric device 6 that is received via the neutral output terminal N and is supplied with a voltage between the neutral output and any phase of the three-phase AC power supply 2 and driven.

  The three-phase 400V AC power supply 2 has three phases R, T, and S, and each phase is input to the three-phase neutral point transformer 4 via the A / C terminal block 31. A voltage of 400 V (interphase voltage) is applied between the three phases. The three-phase neutral point transformer 4 includes a terminal that outputs the three-phase R, T, and S input from the three-phase AC power supply 2 and a neutral output terminal Na that outputs the neutral point of these three phases. In this three-phase neutral point transformer 4, as shown in FIG. 2, the three-phase R, T, and S input from the three-phase AC power source 2 are Y-shaped through windings of the same specification, and from the central connection point. A neutral output terminal Na is pulled out. Since the current capacity of the three-phase neutral point transformer 4 only needs to cover the current capacity flowing through the neutral output terminal Na, the transformer is a small transformer with a weight of less than 20 kg. The voltage between the neutral output terminal Na and each phase is AC 230V.

  Returning to FIG. 1, the power input terminal of the outdoor unit 3 includes R, T, S, and a neutral input terminal N provided on the A / C terminal block 31, and the power from the three-phase AC power source 2 is the A / C. The signal is input to the outdoor unit 3 through the terminal block 31. Among these, the power input terminals R, T, and S are connected to the R, T, and S phases of the three-phase AC power source 2. If the three-phase AC power supply 2 has a neutral output, it is connected to the neutral input terminal N, but if there is no neutral output as in this embodiment, a three-phase neutral point transformer 4 is used instead. In this case, the neutral output terminal Na of the three-phase neutral point transformer 4 is connected to the neutral output terminal N of the A / C terminal block 31. Electric power is supplied from the R, T, S, and N phases of the A / C terminal block 31 to the compressor driving unit 5 and the low-power electric device 6 provided in the outdoor unit 3, respectively.

  The A / C terminal block 31 has a shape as shown in FIG. 3, for example, and serves as a power input terminal for each of R, T, S, and N phases from the left side. The power output terminals of the R, T, and S phases on the right side of the A / C terminal block 31 are connected to the three-phase neutral point transformer 4 and the compressor driving unit 5, respectively. Since any phase of the 400V power supply is mistakenly connected to the N-phase input terminal, it is desirable to attach a caution name plate beside the terminal block so that it is not accidentally connected.

  The compressor drive unit 5 includes a three-phase full-wave rectifier circuit 51, an inverter 52, and a compressor 53. The outputs of the R, T, and S phases that are directly supplied from the three-phase AC power supply 2 via the A / C terminal block 31 are rectified to direct current by the three-phase full-wave rectifier circuit 51, and this direct-current output is supplied to the inverter 52. Power source. The inverter 52 converts the input DC output into three-phase AC and supplies it to the compressor 53 to drive the compressor 53 at a variable speed.

  The low-power electric device 6 includes a control circuit 61, an electric expansion valve 63, a four-way valve coil 64, a fan motor 68, and the like, and these are any one of a neutral output terminal N and a three-phase AC (S phase in FIG. 2). It is comprised so that it may drive as a power supply. That is, a power supply voltage of a single-phase AC 230 V applied between the neutral output terminal N and the S phase is applied to these low power electric devices 6.

  The control circuit 61 issues a command to drive each device in the outdoor unit 3. For example, the compressor 53 is driven based on a control command from the control circuit 61 input to the inverter 52. The control circuit 61 is supplied with power from the neutral output terminal N and the S phase via the DC / DC converter 62.

  The electric expansion valve 63 driven by the pulse motor is also supplied with power from the neutral terminals N and S via the DC / DC converter 62, and the valve is opened based on a control signal from the control circuit 61. The degree is controlled.

  A four-way valve coil that drives a four-way valve that switches the direction of refrigerant flow when switching between cooling and heating between the neutral output terminal N and one of the three-phase alternating currents R, T, and S (phase S in FIG. 2) 64 is connected through a four-way valve relay 65. This four-way valve relay 65 is switched on / off by a control signal from the control circuit 61.

  Further, the output from the neutral output terminal N and the S phase in FIG. 2 is rectified to a direct current by the single-phase full-wave rectifier circuit 66. The rectified DC power supply is supplied to a fan inverter 67 for driving the fan, whereby it is further converted into a variable frequency output AC, and the fan motor 68 is driven at a variable speed.

  The configuration of the air conditioner 1 in the present embodiment is as described above, but when the AC power supply 2 is turned on to the air conditioner 1, the power input terminals R, T, A voltage of 400 V is applied between each S, and the compressor 53 in the outdoor unit 3 is driven. In addition, a voltage of 230 V is applied between the neutral output terminal N and the S phase by the three-phase neutral point transformer 4, and this is taken in for control and drive, thereby constituting the low-power electric device 6. The circuit 61, the electric expansion valve 63, the four-way valve coil 64, the fan motor 68, and the like are driven.

  That is, 230V applied between the neutral output terminal N and the S phase in this embodiment is applied to these low-power electric devices 6, and the three-phase AC power source 2 is 400V. Even if it exists, the voltage of 400V is not necessarily applied. Therefore, if a 200V low-power electric device provided in a three-phase 200V air conditioner is incorporated in a three-phase 400V air conditioner, there is no need to separately prepare a 400V low-power electric device. It becomes possible to share the low-power electric equipment between the three-phase 400V air conditioner and the three-phase 200V air conditioner.

  Further, since the three-phase neutral point transformer 4 is small, it can be housed in an outdoor unit casing. That is, as shown in FIG. 4, the three-phase neutral point transformer 4 is housed inside the outdoor unit 3. The outdoor unit 3 is usually installed outdoors, and the interior of the outdoor unit 3 is configured by a heat exchanger chamber 3a disposed at the top and a machine room 3b provided at the bottom of a partition plate (not shown) disposed horizontally. In the machine room 3b, a compressor 53, an inverter 52, and a part of the low-power electric device 6 that are particularly vulnerable to rainwater are stored. For this reason, the machine room 3b of the outdoor unit 3 is strictly waterproofed to cope with rainfall or the like. Therefore, by storing the three-phase neutral point transformer 4 in the machine room 3b of the outdoor unit 3, it is not necessary to take strict waterproofing measures on the three-phase neutral point transformer 4 itself.

  In this way, the 400 V voltage supplied from the three-phase AC power supply 2 is output by the three-phase neutral point transformer 4 so that the neutral output is output. All of the devices that make up can use parts used in single-phase 200V. In addition, the component used by single phase 200V can generally be used also by single phase 230V. Therefore, there is no need to use a large step-down transformer. In addition, since the parts used in the three-phase 200V air conditioner can be used in the three-phase 400V air conditioner, the parts can be shared, and parts with a particularly high pressure resistance can be used. Since there is no need to provide insulation reinforcement for voltage support, it is possible to provide an air conditioner that can be used in buildings that use a three-phase 400 V power source in Japan. Further, by storing the three-phase neutral point transformer 4 in the outdoor unit 3, waterproofing measures for the three-phase neutral point transformer 4 itself can be simplified, and it is possible to effectively reduce failures such as a short circuit. .

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine the component covering different embodiment suitably.

It is a circuit diagram which shows the wiring in an air conditioner. It is a winding diagram of a three-phase neutral point transformer. It is a figure which shows an A / C terminal block. It is a partial notch figure of the outdoor unit which shows an outdoor unit and the three-phase neutral point transformer accommodated in the inside.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Air conditioner 2 Three-phase 400V AC power supply 3 Outdoor unit 4 Three-phase neutral point transformer 5 Compressor drive part 6 Low electric power equipment 31 A / C terminal block 53 Compressor 61 Control circuit 63 Electric expansion valve 64 Four-way valve coil 68 fan motor

Claims (2)

  A neutral phase, which is connected to a three-phase 400V AC power source, includes a three-phase neutral point transformer having a neutral phase that outputs a neutral point of the three-phase AC power source, and is output from the three-phase neutral point transformer. And a means for supplying electric power between the three-phase AC power source to a low-power electric device, and supplying electric power from the three-phase AC power source to the compressor via the three-phase neutral point transformer An air conditioner comprising means for driving.   The air conditioner according to claim 1, wherein the three-phase neutral point transformer is housed in a housing that houses the compressor.

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