JP4622295B2 - Inverter-driven compressor sleep detection method, start-up method, and inverter-driven compressor - Google Patents

Description

  The present invention relates to a method for detecting a state in which a large amount of liquid refrigerant is dissolved in a lubricating oil in an inverter driven compressor, and an inverter driven compression in response to the absence of a large amount of liquid refrigerant in a lubricating oil. The present invention relates to a method for starting a machine and these devices.

Conventionally, it is known that when the compressor is started in a cooled state, a large amount of liquid refrigerant is dissolved in the lubricating oil, and the lubricating oil becomes diluted and may cause damage to the compressor.
In order to prevent damage to the compressor, the voltage and current applied to the compressor are detected, and the resistance value of the motor winding of the compressor is calculated from this value, and the temperature characteristic of the resistance value is used. It has been proposed to calculate the current temperature of the compressor and to preheat the compressor when the current temperature falls below a predetermined temperature (see Patent Document 1).

Further, the outside air temperature is equal to or lower than the first set temperature at which the refrigerant may stagnate in the compressor, and the radiator temperature for the inverter or the like is equal to or lower than the second set temperature that can be assumed that the inverter is not driven. In this case, it has been proposed to perform energization of the windings of the compressor driving motor (see Patent Document 2).
Japanese Patent Laid-Open No. 5-288411 JP 2000-292014 A

  In the method described in Patent Document 1, only the preheating of the compressor is performed when the current temperature of the compressor becomes a predetermined temperature or less, and it is detected whether or not the liquid refrigerant has stagnated. Therefore, there is a possibility that the compressor is preheated even though the liquid refrigerant has not stagnated in the compressor, and the compressor is preheated even though the liquid refrigerant has stagnated in the compressor. May not be performed. If the compressor is not preheated even though the liquid refrigerant has stagnated in the compressor, the compressor will be driven while the lubricating oil is diluted, leading to damage to the compressor. End up.

  In the method described in Patent Document 2, restraint energization is performed on the windings of the compressor driving motor based on the fact that the outside air temperature and the radiator temperature are equal to or lower than the corresponding set temperatures, respectively. Since it is not detecting whether or not the stagnation has occurred, there is a possibility that the energization of the compressor driving motor is restrained even though the liquid refrigerant is not stagnation in the compressor, There is a possibility that restraint energization is not performed on the windings of the motor for driving the compressor even though the liquid refrigerant has stagnated in the compressor. And even if liquid refrigerant has stagnated in the compressor, if the energization is not performed to the winding of the motor for driving the compressor, the compressor will be driven while the lubricating oil is diluted, The compressor will be damaged.

  The present invention has been made in view of the above-mentioned problems, and provides a method and an apparatus for detecting the stagnation of an inverter-driven compressor that reliably detects the stagnation of a liquid refrigerant. A second object is to provide a method for starting an inverter-driven compressor that detects the absence of liquid refrigerant stagnation and starts the inverter-driven compressor.

The stagnation detection method for an inverter-driven compressor according to the present invention operates using a motor supplied with output power from the inverter as a drive source, compresses the refrigerant, and discharges it to the circulation flow path.
The motor is energized for a predetermined time without operating the compressor, the temperature change of the motor windings of the motor between different timings is measured, and the motor gas is supplied on condition that the measured temperature change is smaller than a predetermined threshold. A method for detecting whether the atmosphere is in a state or the motor is in a liquid refrigerant ,
This is a stagnation detection method in which energization of the motor in a state where the compressor is not operated is performed at a carrier frequency lower than that during normal operation of the compressor .

Therefore, it is possible to detect that the motor is immersed in the liquid refrigerant due to the stagnation of the liquid refrigerant because the temperature change of the motor is small. That is, it is possible to reliably detect the stagnation of the inverter-driven compressor. Further, the leakage current can be reduced.

According to the method for starting an inverter-driven compressor of the present invention, the motor is energized in a state where the compressor is not operated in response to the detection of the sleeping state by the method of claim 1, and the method of claim 1 is used. A method of energizing the motor in order to start the compressor in response to detecting that it is not in the sleeping state, and energizing the motor (11) before starting the compressor during normal operation of the compressor It is the starting method of the inverter drive compressor performed at a lower carrier frequency .

Therefore, the inverter drive compressor can be started only when it is no longer in the sleeping state, and the compressor can be prevented from being damaged. Further, the leakage current can be reduced.

Inverter-driven compressor of this invention operates a motor output power from the inverter is supplied as a driving source, the inverter-driven compressor which discharges the circulation passage to compress the refrigerant,
Energizing means for energizing the motor for a predetermined time without operating the compressor, temperature change measuring means for measuring the temperature change of the motor winding of the motor between different timings, and the measured temperature change is less than a predetermined threshold An inverter driven compressor comprising: a sleeping state detecting means for detecting whether the motor is in a gas atmosphere or the motor is in a liquid refrigerant under the condition of being small. The means is an inverter drive compressor that performs energization to the motor in a state where the compressor is not operated at a carrier frequency lower than that during normal operation of the compressor .

Therefore, it is possible to detect that the motor is immersed in the liquid refrigerant due to the stagnation of the liquid refrigerant because the temperature change of the motor is small. That is, the stagnation of the inverter-driven compressor can be reliably detected. Further, the leakage current can be reduced.

An inverter-driven compressor according to the present invention operates with a motor supplied with output power from the inverter as a drive source, and compresses the refrigerant and discharges it from the circulation flow path without operating the compressor. On condition that the energizing means for energizing the motor for a predetermined time, the temperature change measuring means for measuring the temperature change of the motor winding of the motor between different timings, and the condition that the measured temperature change is smaller than a predetermined threshold Inverter-driven compressor including a state of gas atmosphere or a state of sleep detecting means for detecting whether the motor is in a liquid refrigerant, in response to detecting that it is in a sleeping state In response to detecting that it is not in the sleep state, and non-operation energizing means for energizing the motor without operating the compressor, Includes activation energization means for energizing the motor for moving the energizing means, the power supply to the motor before the compressor starts, a compressor usually inverter-driven compressor which performs at a lower carrier frequency than during the operation of.
Therefore, the inverter drive compressor can be started only when it is no longer in the sleeping state, and the compressor can be prevented from being damaged. Further, the leakage current can be reduced.

An inverter-driven compressor according to the present invention operates with a motor supplied with output power from the inverter as a drive source, and compresses the refrigerant and discharges it from the circulation flow path without operating the compressor. On condition that the energizing means for energizing the motor for a predetermined time, the temperature change measuring means for measuring the temperature change of the motor winding of the motor between different timings, and the condition that the measured temperature change is smaller than a predetermined threshold An inverter-driven compressor including a state of being in a gas atmosphere or a sleeping state detecting means for detecting whether the motor is in a liquid refrigerant, wherein the energizing means is a motor in a state where the compressor is not operated. The compressor is turned on in response to detecting that it is in a sleep state by conducting power to the motor at a lower carrier frequency than during normal operation of the compressor. Non-operation energization means for energizing the motor in a non-operating state, and activation energization means for energizing the motor to activate the compressor in response to detecting that it is not in the sleep state, the energization means, This is an inverter-driven compressor that energizes the motor before starting the compressor at a lower carrier frequency than during normal operation of the compressor.
Therefore, the inverter drive compressor can be started only when it is no longer in the sleeping state, and the compressor can be prevented from being damaged. Further, the leakage current can be reduced.

  The present invention has a specific effect that the stagnation of the inverter-driven compressor can be reliably detected.

  Another invention has a specific effect that the inverter-driven compressor can be started only when it is no longer in the sleeping state, and damage to the compressor can be prevented.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a stagnation detection method, an activation method, and these apparatuses for an inverter-driven compressor according to the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic block diagram showing a configuration of a main part of an air conditioner outdoor unit to which a stagnation detection method and an activation method of an inverter driven compressor according to the present invention are applied.

  This air conditioner outdoor unit receives a compressor 1 using a motor 11 as a drive source and an AC power source (preferably a three-phase AC power source) 2 as inputs, performs a predetermined process, and supplies driving power to the motor 11 A machine control unit 3 and a motor temperature detection unit 4 that detects the temperature of the motor 11 and supplies the detected temperature to the compressor control unit 3.

As the motor 11, those having various configurations such as a three-phase synchronous motor can be adopted.
The motor temperature detection unit 4 may be a temperature detection element such as a thermocouple, but calculates the motor winding resistance from the motor voltage and motor current, and calculates the motor temperature in consideration of the temperature characteristics of the resistance. (For example, refer to Japanese Patent Laid-Open No. 5-288411).
As shown in FIG. 2, the compressor control unit 3 outputs a three-phase AC power by performing a predetermined switching operation with a DC power source 31 such as a converter having the AC power source 2 as an input and the DC power source 31 as an input. Detected by using the three-phase inverter 32 supplied to the motor 11 as drive power, the resistor 33 connected between the DC power supply 31 and the three-phase inverter 32, the voltage output from the DC power supply 31, and the resistor 33 Current processing and the temperature of the motor 11 are input, and predetermined processing is performed (for example, determination processing of motor winding resistance, determination processing of motor temperature, such as determination of whether to perform a phase loss operation or normal operation) And a microcomputer 34 that outputs a control signal (inverter switching signal) for each transistor of the three-phase inverter 32.

  For example, as shown in FIG. 3, the compressor 1 has a compression mechanism 12 and a motor 11 as a drive source inside a compressor casing 13 having a refrigerant discharge pipe 14 and a refrigerant suction pipe 15. Reference numeral 16 denotes a terminal for supplying power to the motor 11.

FIG. 4 is a flowchart for explaining an example of the stagnation detection process of the inverter-driven compressor.
In step SP1, the temperature T1 of the motor coil (motor winding) is measured, and in step SP2, the motor coil is energized for a predetermined time (in this case, the energization is such that the motor is not operated. The energization time is determined by the difference between T2-T1 when the motor is in the gas atmosphere and T2-T1 when the motor is in the liquid refrigerant based on the measurement accuracy of temperature detection. In step SP3, the motor coil temperature T2 is measured again, and in step SP4, it is determined whether or not (T2-T1) is smaller than a predetermined reference value T0. .

If it is determined that (T2−T1) <T0, it is determined in step SP5 that the inverter-driven compressor is sleeping.
Conversely, if it is determined that (T2−T1) ≧ T0, it is determined in step SP6 that the inverter-driven compressor is not stagnation.

  FIG. 5 is a diagram illustrating an example of a change with time in the thermocouple temperature corresponding to the sleeping state and the non-sleeping state of the compressor.

  In FIG. 5, A shows the change with time of the thermocouple temperature corresponding to the non-sleeping state (the state where the motor is in the gas atmosphere), and the temperature is greatly increased as the energization time elapses. I understand. On the contrary, B shows the change with time of the thermocouple temperature corresponding to the stagnation state (the state where the motor is in the liquid refrigerant), and it can be seen that the temperature hardly increases as the energization time elapses.

  Therefore, by determining the magnitude of the temperature difference (T2-T1) and the reference value T0, it is possible to reliably determine whether the state is A or B in FIG. It is possible to determine whether the state is a sleeping state or not.

  FIG. 6 is a flowchart for explaining another example of the stagnation detection process of the inverter-driven compressor.

  In step SP1, the motor coil is energized. In step SP2, the temperature T01 of the motor coil when a predetermined time T1 has elapsed from the start of energization is measured. In step SP3, the motor at the time when the predetermined time T1 + Δt has elapsed from the start of energization. The coil temperature T02 is measured, and in step SP4, it is determined whether or not the differential value (T02−T01) / Δt is smaller than the reference value T00 ′.

  If (T02−T01) / Δt <T00 ′, it is determined in step SP5 that the compressor is sleeping.

  On the other hand, if (T02−T01) / Δt ≧ T00 ′, it is determined in step SP6 that the compressor is not sleeping.

  In this case, since the time interval between temperature measurements can be shortened, the time required for stagnation detection can be shortened.

As can be seen from the above description, the predetermined time T1 is set to a time when the difference between the slope of the curve A (differential coefficient) and the slope of the curve B (differential coefficient) in FIG.
FIG. 7 is a flowchart for explaining an example of the startup process of the inverter-driven compressor.
In response to the power supply of the outdoor unit being turned on, in step SP1, the compressor stagnation is detected, and in step SP2, it is determined whether or not the compressor is slumbered.

  And when it determines with the compressor not sleeping, in step SP3, a compressor is started.

  Conversely, if it is determined that the compressor is sleeping, in step SP4, the motor is energized so as not to rotate, and then the processing in step SP1 is performed again.

Note that the process of step SP1 is, for example, the process of FIG. 4 or the process of FIG.
The processing in step SP4 is, for example, phase loss energization for the motor.
In this case, since the compressor is activated only when it is determined that the compressor is not stagnation, the compressor can be prevented from being damaged.

  Also, if it is determined that the compressor is sleeping, the motor coil functions as a heating element by energizing the motor so that it does not rotate, and the lubricating oil is melted by raising the temperature of the lubricating oil. The refrigerant is gasified. Therefore, by continuing the process of energizing the motor so as not to rotate, the refrigerant can be finally gasified almost completely, and the compressor can be kept in a state of not sleeping.

  Therefore, the compressor can be started only when it is determined that the compressor is not sleeping, regardless of the state of the refrigerant and the lubricating oil at the time when the outdoor unit is turned on. Can be prevented in advance.

  In the above description, the processing of the flowchart of FIG. 7 is performed when the power of the outdoor unit is turned on. However, the flowchart of FIG. 7 is also performed when a compressor operation command is supplied during normal operation. Can be processed.

  In each of the above embodiments, in the process of energizing the motor so as not to rotate, it is preferable to set the carrier frequency of the inverter included in the compressor drive unit 3 to be lower than the carrier frequency during normal operation.

  Specifically, it is preferably set to about 300 Hz or less, and a leakage current of 1 mA or less, which is a leakage standard of the Electrical Appliance and Material Safety Law, can be realized.

  In this case, as shown in FIG. 8, the leakage current can be reduced, and the inconvenience that the leakage breaker operates during the process of energizing the motor so as not to rotate can be prevented. be able to.

  Moreover, it becomes difficult for a person to get an electric shock due to a reduction in leakage current.

It is a schematic block diagram which shows the structure of the principal part of the air conditioner outdoor unit to which the stagnation detection method of the inverter drive compressor of this invention and the starting method are applied. It is a block diagram which shows the structure of a compressor control part in detail. It is a longitudinal cross-sectional view which shows the structure of a compressor. It is a flowchart explaining an example of the sleep detection process of an inverter drive compressor. It is a figure which shows an example of the time-dependent change of the thermocouple temperature corresponding to the sleep state of a compressor, and the non-sleep state. It is a flowchart explaining the other example of the stagnation detection process of an inverter drive compressor. It is a flowchart explaining an example of the starting process of an inverter drive compressor. It is a figure which shows an example of a leakage current-carrier frequency characteristic.

Explanation of symbols

1 Compressor 11 Motor

Claims (5)

In an inverter driven compressor (1) that operates using a motor (11) to which output power from an inverter is supplied as a drive source, compresses refrigerant, and discharges it from a circulation flow path,
Energizing the motor (11) for a predetermined time without operating the compressor (1),
Measure the temperature change of the motor winding of the motor (11) between different timings,
It detects whether the state the measured temperature change or state motor on the condition that less than a predetermined threshold value (11) is in gas atmosphere or motor (11) is in the liquid refrigerant
A asleep detection method inverter driven compressor,
A method for detecting stagnation of an inverter-driven compressor, wherein energization of the motor (11) without operating the compressor (1) is performed at a carrier frequency lower than that during normal operation of the compressor (1) . Energizing the motor (11) in a state where the compressor (1) is not operated in response to detecting that it is in the sleeping state by the method of claim 1; and
In response to detecting that the device is not in a sleep state by the method of claim 1, energizing the motor (11) to start the compressor (1)
A method for starting an inverter driven compressor including
A method for starting an inverter-driven compressor, wherein energization of the motor (11) before starting the compressor is performed at a carrier frequency lower than that during normal operation of the compressor. In an inverter driven compressor (1) that operates using a motor (11) to which output power from an inverter is supplied as a drive source, compresses refrigerant, and discharges it from a circulation flow path,
Energization means for energizing the motor (11) for a predetermined time without operating the compressor (1);
A temperature change measuring means for measuring a temperature change of the motor winding of the motor (11) between different timings;
A sleeping state detecting means for detecting whether the motor (11) is in a gas atmosphere or the motor (11) is in a liquid refrigerant on the condition that the measured temperature change is smaller than a predetermined threshold.
An inverter driven compressor including
The said electricity supply means is an inverter drive compressor which performs electricity supply to the motor (11) in the state which does not operate a compressor (1) with a carrier frequency lower than the time of normal operation of a compressor (1). In an inverter driven compressor (1) that operates using a motor (11) to which output power from an inverter is supplied as a drive source, compresses refrigerant, and discharges it from a circulation flow path,
Energization means for energizing the motor (11) for a predetermined time without operating the compressor (1);
A temperature change measuring means for measuring a temperature change of the motor winding of the motor (11) between different timings;
A sleeping state detecting means for detecting whether the motor (11) is in a gas atmosphere or the motor (11) is in a liquid refrigerant on the condition that the measured temperature change is smaller than a predetermined threshold.
An inverter driven compressor including
Non-operation energizing means for energizing the motor (11) in a state where the compressor (1) is not operated in response to detecting that it is in the sleeping state; and
Start energization means for energizing the motor (11) to activate the compressor (1) in response to detecting that it is not in the sleeping state.
Including
The energization means is an inverter-driven compressor that energizes the motor (11) before starting the compressor at a lower carrier frequency than during normal operation of the compressor (1). In an inverter driven compressor (1) that operates using a motor (11) to which output power from an inverter is supplied as a drive source, compresses refrigerant, and discharges it from a circulation flow path,
Energization means for energizing the motor (11) for a predetermined time without operating the compressor (1);
A temperature change measuring means for measuring a temperature change of the motor winding of the motor (11) between different timings;
A sleeping state detecting means for detecting whether the motor (11) is in a gas atmosphere or the motor (11) is in a liquid refrigerant on the condition that the measured temperature change is smaller than a predetermined threshold.
An inverter driven compressor including
The energization means energizes the motor (11) without operating the compressor (1) at a lower carrier frequency than during normal operation of the compressor (1),
Non-operation energizing means for energizing the motor (11) in a state where the compressor (1) is not operated in response to detecting that it is in the sleeping state; and
Start energization means for energizing the motor (11) to activate the compressor (1) in response to detecting that it is not in the sleeping state.
Including
The energization means is an inverter-driven compressor that energizes the motor (11) before starting the compressor at a lower carrier frequency than during normal operation of the compressor (1).

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