JP2006166569A - Air conditioning apparatus - Google Patents

Air conditioning apparatus Download PDF

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Publication number
JP2006166569A
JP2006166569A JP2004353085A JP2004353085A JP2006166569A JP 2006166569 A JP2006166569 A JP 2006166569A JP 2004353085 A JP2004353085 A JP 2004353085A JP 2004353085 A JP2004353085 A JP 2004353085A JP 2006166569 A JP2006166569 A JP 2006166569A
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Japan
Prior art keywords
electrolytic capacitor
compressor
life
temperature
main
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Pending
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JP2004353085A
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Japanese (ja)
Inventor
Keisuke Otsuka
啓右 大塚
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Daikin Ind Ltd
ダイキン工業株式会社
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Priority to JP2004353085A priority Critical patent/JP2006166569A/en
Publication of JP2006166569A publication Critical patent/JP2006166569A/en
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Abstract

<P>PROBLEM TO BE SOLVED: To improve the detection accuracy of a service life without need for employing a special electrolytic capacitor. <P>SOLUTION: This air conditioning apparatus includes: a main-circuit current detection section 11 for detecting a current of a main circuit from a terminal voltage of a shunt resistor 6; a radiation fin temperature detection section 12 for detecting a temperature of radiation fins from an output signal of a thermister 7 for radiation fin temperature detection; and a service life calculation section 13 which estimates a ripple current of the main-circuit electrolytic capacitor 3 from a main-circuit current as well as an ambient temperature of the main-circuit electrolytic capacitor 3 from a temperature of the radiation fins, supplies a control signal for controlling a compressor 5 to an inverter 4, and calculates the service life of the main-circuit electrolytic capacitor 3 using the ripple current, the ambient temperature and a compressor control status. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an air conditioner configured to drive a compressor for compressing refrigerant by supplying output power from an inverter, and more particularly to such an air conditioner that detects the life of a power supply circuit. The present invention relates to an air conditioning apparatus.

  In an air conditioner configured to drive a compressor for refrigerant compression by supplying output power from an inverter, an electrolytic capacitor is used in a power control main circuit such as an inverter and a converter. The lifetime due to capacity deterioration is directly handled as the lifetime of the air conditioner.

  In consideration of this, a method for detecting the life of an electrolytic capacitor has been proposed (see Patent Document 1 and Patent Document 2).

  Patent Document 1 discloses that a life detection electrolytic capacitor is arranged close to a main circuit electrolytic capacitor that is a life detection target, and the life of the main circuit electrolytic capacitor is detected from the life detection electrolytic capacitor. Is described.

  Patent Document 2 describes that a life detection capacitor is integrated with a main circuit electrolytic capacitor that is a life detection target, and the life of the main circuit electrolytic capacitor is detected from the life detection capacitor.

It has also been proposed to integrate the operation time of the air conditioner using an energization integration timer or the like and use this integration time as a standard for life detection.
Japanese Patent No. 2900579 JP 2001-327162 A

  When Patent Document 1 is adopted, the temperature rise due to self-heating caused by the ripple current flowing into the main circuit electrolytic capacitor and the life reduction due to this temperature rise cannot be taken into account, so the life detection accuracy is reduced. There is an inconvenience. In particular, in this case, a life longer than the actual life is detected.

  When Patent Document 2 is adopted, the life detection accuracy can be improved in consideration of the temperature rise inside the main circuit electrolytic capacitor, but a special electrolytic capacitor is required and a dedicated design is required. At the same time, there is a disadvantage that the cost becomes high.

  When an energization timer is used, the design and configuration are simple and the cost can be kept low. However, since the temperature of the main circuit electrolytic capacitor is not taken into account at all, the life detection accuracy is significantly reduced. There is an inconvenience.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an air conditioner that does not require the use of a special electrolytic capacitor and can improve the detection accuracy of the lifetime.

  The air conditioner of the present invention is configured to drive a compressor for refrigerant compression by supplying output power from an inverter, and detects a temperature in the vicinity of an electrolytic capacitor included in a power control main circuit. Temperature detecting means for detecting, input current detecting means for detecting the input current of the compressor, compressor state detecting means for detecting whether the compressor is in operation or not, and in the vicinity of the electrolytic capacitor And a life calculation means for calculating the life of the electrolytic capacitor in consideration of the influence of the ambient temperature and the influence of self-heating with the input of the temperature and the input current of the compressor.

  However, in response to the fact that the compressor is not in operation, the life calculation means calculates the life of the electrolytic capacitor in consideration of only the influence of the ambient temperature, and the compressor is in operation. In response to this, it is preferable to calculate the lifetime of the electrolytic capacitor in consideration of the influence of the ambient temperature and the influence of self-heating.

  In the air conditioner according to the present invention, when the air conditioning operation is performed by driving the compressor for refrigerant compression by supplying the output power from the inverter, the temperature control means includes the power control main circuit. The temperature in the vicinity of the electrolytic capacitor is detected, the input current detection means detects the compressor input current, and the compressor state detection means detects whether the compressor is operating or not operating. . Then, the lifetime calculation means can calculate the lifetime of the electrolytic capacitor taking the temperature near the electrolytic capacitor and the input current of the compressor as inputs and taking into consideration the influence of the ambient temperature and the influence of self-heating.

  Therefore, it is possible to accurately calculate the life of the electrolytic capacitor, and thus the life of the air conditioner, and to take necessary measures at the appropriate time due to the arrival of the life.

  The life calculating means calculates the life of the electrolytic capacitor in consideration of only the influence of the ambient temperature in response to the fact that the compressor is not in operation, and the compressor is in operation. In response to this, in the case where the lifetime of the electrolytic capacitor is calculated in consideration of the influence of the ambient temperature and the influence of self-heating, the calculation accuracy of the lifetime of the electrolytic capacitor can be further improved.

  The present invention has a specific effect that the life of the air conditioner can be accurately detected.

  Embodiments of an air conditioner according to the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic view showing a main part of an air conditioner of the present invention.

  In FIG. 1, an AC / DC converter 2 that outputs DC power with a three-phase AC power supply 1 as an input, a main circuit electrolytic capacitor 3 that smoothes DC power, and the smoothed DC power is converted to AC power. The inverter 4 and the compressor 5 which uses the motor driven by the alternating current power from the inverter 4 as a drive source are provided. A current detecting shunt resistor 6 is connected between one terminal of the main circuit electrolytic capacitor 3 and a corresponding input terminal of the inverter 4. In addition, the inverter 4 is provided with a thermistor 7 for detecting a fin temperature, which is mounted on a radiator of the power device.

  A main circuit current detector 11 that detects the current of the main circuit from the voltage across the shunt resistor 6, and a radiating fin temperature detector 12 that detects the temperature of the radiating fin from the output signal of the radiating fin temperature detection thermistor 7, The ripple current of the main circuit electrolytic capacitor 3 is estimated from the main circuit current, the ambient temperature of the main circuit electrolytic capacitor 3 is estimated from the temperature of the radiation fin, and the control signal for controlling the compressor 5 is supplied to the inverter 4. , A life calculator 13 for calculating the life of the main circuit electrolytic capacitor 3 using the ripple current, the ambient temperature, and the compressor control state, and a remaining life time storage unit 14 for holding the remaining life time. The remaining life time held in the time storage unit 14 is output to a remote monitoring system or the like as necessary.

  The main circuit current detection unit 11, the radiating fin temperature detection unit 12, and the life calculation unit 13 can be configured by hardware, but are configured by incorporating software as a function of the outdoor unit control microcomputer. Is preferred.

  Moreover, since the structure for controlling the inverter 4 is conventionally well-known, detailed description is abbreviate | omitted.

  The process in the lifetime calculation unit 13 will be described in detail.

  The process of estimating the ripple current of the main circuit electrolytic capacitor 3 is, for example, that the input current (load) of the compressor is known by the shunt resistance when the compressor is operating. It can be achieved as conventionally known by control parameters such as capacitor capacity and main circuit power supply voltage.

  In recent years, many air conditioners are equipped with DC compressors (compressors that use brushless DC motors as the drive source). To drive a DC compressor, the inverter output current (= compressor input current) A shunt resistor (or current sensor) for detecting the position of the rotor is mounted. By using this shunt resistor, the ripple current of the main circuit electrolytic capacitor 3 can be estimated without increasing the cost.

  The process of estimating the ambient temperature is performed by, for example, measuring the relationship between the heat radiation fin temperature and the ambient temperature of the electrolytic capacitor in advance in a reliability test and holding it as a table and referring to the table as necessary. Can be achieved.

  The calculation of the life of the main circuit electrolytic capacitor 3 is performed as follows, for example, in a state where the compressor is driven and a state where the compressor is not driven.

When the compressor is not driven:
In this case, since it is not necessary to consider the self-heating of the main circuit electrolytic capacitor 3 due to the ripple current, the life L (time) in actual use is calculated using the Arrhenius law formula (Equation 1), Use to calculate remaining life time. In Equation 1, L0 is the life (hour) at the maximum use temperature, Tmax is the maximum use temperature (° C.), and Ta is the ambient temperature (° C.).

  To explain further with reference to the flowchart of FIG. 2, in step SP1, the device is first turned on (starts remaining life time calculation), and an initial value (eg, a time guaranteed by the manufacturer) is set to L0. To do. Next, in step SP2, for example, an operation time timer for 1 hour is started, and Ta sampling (for example, sampling of Ta as an average of 1 hour) is started. And in step SP3, it waits until driving time passes for 1 hour. Thereafter, in step SP4, the life conversion time Lt (life conversion time per hour) at the maximum operating temperature is calculated from Ta (average value for 1 hour) according to Arrhenius' law (Equation 2). Tmax and Ta are the same as those in Equation 1.

  Thereafter, in step SP5, Lt is subtracted from L0 to calculate the remaining life time, and this is stored in the remaining life time storage unit 14 as a new L0. Thereafter, the process of step SP2 is performed again.

  Therefore, the remaining lifetime can be updated every hour.

  Specifically, if Tmax = 85 ° C. and Ta = 65 ° C., Lt = 0.25 hours, and if L0 = 3000 hours, the remaining life time is 3000−0.25 = 2999.75 hours. Become.

Driving compressor:
In this case, since it is necessary to consider the self-heating of the main circuit electrolytic capacitor 3 due to the ripple current, the estimated actual life L (time) is calculated using Equation 3 instead of the Arrhenius law equation, and this is used. And calculate the remaining life time. However, in Equation 3, Lr is the actual life (hours) when the rated voltage is applied at the maximum operating temperature (ripple superimposed), Tmax is the maximum operating temperature (° C), Ta is the ambient temperature (° C), and K is the ripple. Acceleration coefficient (2 if less than allowable ripple current, 4 if more than allowable ripple current), ΔT0 is temperature rise due to ripple current (element center, ° C), I is applied ripple current (A · rms), and I0 is at maximum operating temperature Rated ripple current (A · rms).

  Formula 3 is obtained by adding an influence term of self-heating to Formula 1. And the influence term of self-heating is calculated | required as follows, for example.

The amount of heat P generated by the ripple current I is proportional to the square I 2 of the ripple current and the equivalent internal series resistance (ESR) R (Ω) as shown in the following equation.
P = I 2 × R
From the above equation, the temperature rise ΔT (deg) inside the main circuit electrolytic capacitor 3 is obtained as follows, and is proportional to the square of the ripple current I 2 and ESR, and inversely proportional to the surface area A (cm 2 ). . H is a heat dissipation coefficient (about 1.5 to 2.0 × 10 −3 W / cm 2 · ° C.).
ΔT = (I 2 × R) / (A × H)
Therefore, by adding a self-heating term to Equation 1, the life estimation formula is obtained as shown in Equation 4. Note that K is a ripple acceleration coefficient (2 if it is less than the allowable ripple current, 4 if it is more than the allowable ripple current).

  Since Equation 4 is based on the life limit value Ld of DC life, the influence term of self-heating is always smaller than 1 and works in the direction of becoming shorter than the life limit value of DC life.

  In addition, capacitor manufacturers specify the life value Lr when the rated ripple current is superimposed at the maximum operating (guaranteed) temperature and the temperature rise value ΔT0 at the center of the capacitor. By rewriting Equation 4 using ΔT0, Equation 5 is obtained.

  Then, by replacing ΔT in Equation 5 with current, Equation 3 is obtained.

  Therefore, the remaining lifetime can be detected with high accuracy by selecting one of Equations 1 and 3 depending on whether or not the compressor 5 is operating.

  FIG. 3 is a schematic diagram showing how the remaining lifetime is gradually shortened.

  Region (1) in FIG. 3 is a period in which the compressor is not operating, for example, a period in which the outside air temperature is low and the air conditioner is stopped as in winter, and the remaining lifetime is almost short. Don't be. Region (3) is a period in which the compressor is not operating, for example, a period in which the outside air temperature is high as in summer, and the remaining lifetime is gradually shortened. Region (2) is a period in which the outside air temperature is high as in summer, for example, and is a period in which the compressor is operating, and the remaining lifetime is rapidly shortened.

  Therefore, in practice, the remaining lifetime is shortened by generating the regions (1), (2), and (3) in an arbitrary order.

  The detected remaining lifetime is periodically stored (updated) in the remaining lifetime storage unit 14 and supplied to the outside through a communication network as necessary.

  Therefore, it can be applied to systems that collectively monitor and control the air conditioner of the entire building, and systems that prevent remote control of air conditioners and save energy by remote monitoring. Can be detected with high accuracy, and a proposal for updating the air conditioner can be made at just the right time.

  The present invention is not limited to the above-described embodiment. When a device for detecting the temperature in the vicinity of the main circuit electrolytic capacitor 3 is mounted, this thermistor for detecting the fin temperature is used instead of the thermistor for detecting the fin temperature. It is possible to employ a device. It is also possible to adopt a current sensor instead of the shunt resistor. Furthermore, a power-backed-up RAM, a non-volatile memory, or the like can be employed as the remaining life time storage unit 14.

It is the schematic which shows the principal part of the air conditioning apparatus of this invention. It is a flowchart explaining an example of the calculation process of remaining lifetime. It is the schematic which shows a mode that the remaining life time becomes short gradually.

Explanation of symbols

3 Main Circuit Electrolytic Capacitor 4 Inverter 5 Compressor 6 Shunt Resistor 7 Radiation Fin Temperature Detection Thermistor 11 Main Circuit Current Detection Unit 12 Radiation Fin Temperature Detection Unit 13 Life Calculation Unit


Claims (2)

  1. An air conditioner configured to drive a refrigerant compression compressor (5) by supplying output power from an inverter (4),
    Temperature detection means (7) (12) for detecting the temperature in the vicinity of the electrolytic capacitor (3) included in the power control main circuit, and input current detection means (6) (11) for detecting the input current of the compressor (5) ), Compressor state detecting means (13) for detecting whether the compressor (5) is operating or not operating, the temperature in the vicinity of the electrolytic capacitor (3), the compressor (5) An air conditioner comprising: life calculation means (13) for calculating the life of the electrolytic capacitor (3) in consideration of the influence of ambient temperature and the influence of self-heating using the input current as an input.
  2. In response to the fact that the compressor (5) is not in operation, the life calculation means (13) calculates the life of the electrolytic capacitor (3) considering only the influence of the ambient temperature, The air conditioner according to claim 1, wherein the life of the electrolytic capacitor (3) is calculated in consideration of the influence of ambient temperature and the influence of self-heating in response to the fact that 5) is operating. apparatus.



JP2004353085A 2004-12-06 2004-12-06 Air conditioning apparatus Pending JP2006166569A (en)

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Application Number Priority Date Filing Date Title
JP2004353085A JP2006166569A (en) 2004-12-06 2004-12-06 Air conditioning apparatus

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Application Number Priority Date Filing Date Title
JP2004353085A JP2006166569A (en) 2004-12-06 2004-12-06 Air conditioning apparatus

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008211964A (en) * 2007-01-29 2008-09-11 Daikin Ind Ltd Motor drive controller, hybrid system, and drive control method of motor drive controller
EP1983640A3 (en) * 2007-04-20 2011-01-12 Hitachi Industrial Equipment Systems Co., Ltd. Power conversion apparatus and method of estimating power cycle life
US8401803B2 (en) 2007-08-31 2013-03-19 Vacon Oyj Determination of the lifetime of a component
US20140008998A1 (en) * 2012-07-05 2014-01-09 Visteon Global Technologies, Inc. Method for operating an inverter of an electrical refrigerant compressor making use of dc link electrolyte capacitors
JP2015089172A (en) * 2013-10-29 2015-05-07 株式会社デンソー Power conversion device

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008211964A (en) * 2007-01-29 2008-09-11 Daikin Ind Ltd Motor drive controller, hybrid system, and drive control method of motor drive controller
EP1983640A3 (en) * 2007-04-20 2011-01-12 Hitachi Industrial Equipment Systems Co., Ltd. Power conversion apparatus and method of estimating power cycle life
US7904254B2 (en) 2007-04-20 2011-03-08 Hitachi Industrial Equipment Systems Co., Ltd. Power conversion apparatus and method of estimating power cycle life
US8401803B2 (en) 2007-08-31 2013-03-19 Vacon Oyj Determination of the lifetime of a component
US20140008998A1 (en) * 2012-07-05 2014-01-09 Visteon Global Technologies, Inc. Method for operating an inverter of an electrical refrigerant compressor making use of dc link electrolyte capacitors
US9825615B2 (en) * 2012-07-05 2017-11-21 Hanon Systems Method for operating an inverter of an electrical refrigerant compressor making use of DC link electrolyte capacitors
JP2015089172A (en) * 2013-10-29 2015-05-07 株式会社デンソー Power conversion device

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