CN100406816C - Method and device for preheating operation of frequency conversion driven compressor - Google Patents

Abstract

According to the present invention, the leakage current can be reduced when the compressor driving motor is energized without operating the compressor. Set the carrier frequency of the inverter to be lower than that during normal operation, and conduct open-phase energization to the motor.

Description

Method and device for preheating operation of frequency conversion driven compressor

technical field

The present invention relates to a preheating operation method and device for heating up a variable frequency drive compressor.

Background technique

It has been known for a long time that when the compressor is started in a cold state, a large amount of liquid refrigerant will be dissolved in the lubricating oil, which will dilute the lubricating oil and cause the compressor to be damaged.

In order to prevent the damage of the compressor, a technology is proposed: detect the voltage and current applied to the compressor, calculate the resistance value of the motor winding of the compressor according to the value, and use the temperature characteristic of the resistance value to calculate the current temperature of the compressor, at the current temperature When the temperature is lower than the predetermined temperature, the compressor is preheated (refer to Japanese Patent Application Laid-Open No. 5-288411).

In addition, a technology is proposed: when the atmospheric temperature is below the first set temperature at which the compressor may be immersed in the refrigerant, and the temperature of the radiator for the inverter etc. is at the second setting at which it can be estimated that the inverter will not be driven When the temperature is lower than that, the winding of the motor for driving the compressor is energized in a locked-rotor state (open-phase energization) (refer to Japanese Patent Laid-Open No. 2000-292014).

invention disclosure

The technical problem to be solved by the invention

In patent document 1, the preheating of the compressor adopts direct current preheating. In Patent Document 2, the preheating of the compressor adopts locked-rotor energization (open-phase energization).

However, there is no description of changing the carrier frequency of the inverter, so the same carrier frequency as in normal operation is used. In addition, the carrier frequency is set quite high in consideration of noise, etc., so when performing DC warm-up with the motor for driving the compressor, or energizing the motor for driving the compressor at a stall, if the compressor is driving If the electric motor is immersed in the liquid refrigerant, the leakage current will inevitably increase greatly, and a malfunction of the leakage automatic circuit breaker will occur.

In view of the above problems, an object of the present invention is to provide an inverter that can reduce the leakage current when the compressor driving motor is immersed in lubricating oil and the compressor driving motor is energized without operating the compressor. A preheating operation method and device for driving a compressor.

Technical solutions for technical problems

In the warm-up operation method of an inverter-driven compressor according to the present invention, the inverter-driven compressor operates an electric motor supplied with output power from an inverter as a driving source, compresses refrigerant and discharges it into a circulation flow path, and the preheating The hot running method is a method of energizing the motor by operating the inverter at a lower carrier frequency than in normal operation without operating the compressor.

At this time, since the motor is energized without operating the compressor, even if the liquid refrigerant dissolves into the lubricating oil, the possibility of damage can be prevented, and the temperature of the compressor can be increased to dissolve the refrigerant into the lubricating oil. vaporization of the refrigerant. In addition, even when the motor is immersed in lubricating oil, since the carrier frequency is lowered, the leakage current can be reduced, and malfunctions such as malfunction of the leakage automatic circuit breaker can be suppressed.

The carrier frequency lower than normal operation may be lower than the carrier frequency when generating the rated cooling or heating capacity, or lower than the carrier frequency when generating 1/2 of the rated cooling or heating capacity, It may also be a carrier frequency lower than the highest carrier frequency when the compressor speed is between 10rps and 120rps.

In the warm-up operation device of an inverter-driven compressor according to the present invention, the inverter-driven compressor operates an electric motor supplied with output power from an inverter as a drive source, compresses refrigerant and discharges it into a circulation flow path. The thermal operation device includes energization control means for energizing the motor by operating the inverter at a carrier frequency lower than that during normal operation without operating the compressor.

At this time, since the motor is energized without operating the compressor, even if the liquid refrigerant dissolves into the lubricating oil, the possibility of damage can be prevented, and the temperature of the compressor can be increased to dissolve the refrigerant into the lubricating oil. vaporization of the refrigerant. In addition, even when the motor is immersed in lubricating oil, since the carrier frequency is lowered, the leakage current can be reduced, and malfunctions such as malfunction of the leakage automatic circuit breaker can be suppressed.

The carrier frequency lower than normal operation may be lower than the carrier frequency when generating the rated cooling or heating capacity, or lower than the carrier frequency when generating 1/2 of the rated cooling or heating capacity, It may also be a carrier frequency lower than the highest carrier frequency when the compressor speed is between 10rps and 120rps.

Invention effect

Leakage current can be reduced even when the motor is immersed in lubricating oil, and malfunctions such as malfunction of the leakage automatic circuit breaker can be suppressed.

Description of drawings

Fig. 1 is a schematic block diagram showing the configuration of main parts of an outdoor unit of an air conditioner to which the method of detecting immersion and starting of an inverter-driven compressor according to the present invention is applied.

Fig. 2 is a block diagram showing in detail the configuration of a compressor control unit.

Fig. 3 is a longitudinal sectional view showing the configuration of the compressor.

Fig. 4 is a flowchart illustrating an example of warm-up processing for an inverter-driven compressor.

FIG. 5 is a graph showing an example of leakage current-carrier frequency characteristics.

Detailed ways

The embodiments of the preheating operation method and device of the variable frequency drive compressor of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a schematic block diagram showing the configuration of main parts of an outdoor unit of an air conditioner to which the method for warming up an inverter-driven compressor according to the present invention is applied.

The outdoor unit of the air conditioner includes: a compressor 1 driven by a motor 11;

The motor 11 can adopt various structures such as a three-phase synchronous motor.

As shown in Figure 2, the compressor control unit 3 includes: a DC power supply 31 such as an inverter with the AC power supply 2 as an input; Three-phase AC power is supplied to the motor 11 as driving power; a resistor 33 connected between the DC power supply 31 and the three-phase inverter 32; Predetermined processing is performed for the input (for example, determination of whether to perform open-phase operation or normal operation, etc.), and a control signal (frequency conversion signal) is output to each transistor of the three-phase inverter 32 .

For example, as shown in FIG. 3 , the compressor 1 includes a compression mechanism unit 12 and a motor 11 as a driving source inside a compressor housing 13 having a refrigerant discharge pipe 14 and a refrigerant suction pipe 15 . In addition, 16 is a terminal for supplying electric power to the motor 11 .

Fig. 4 is a flowchart illustrating an example of warm-up processing for an inverter-driven compressor.

In step SP1, during compressor operation, the carrier frequency of the inverter is set to the first carrier frequency during normal operation. Next, in step SP2, if the compressor stops running, then in step SP3, the carrier frequency of the inverter is set to a second carrier frequency lower than the first carrier frequency, and the compressor is pre-loaded by performing open-phase power-on. hot. Next, when an activation command of the compressor is input, the compressor is activated in step SP4.

Here, the completion of the preheating of the compressor can be detected through temperature detection, open-phase energization time detection, and the like.

Therefore, if the processing of the flow chart shown in Fig. 4 is carried out, the compressor must be preheated by opening phase energization before the compressor is started, so the compressor can be started after the temperature rises.

In addition, in the embodiment of FIG. 4 , in the process of energizing the motor in a non-rotating state, the carrier frequency of the inverter included in the compressor drive unit 3 is set lower than the carrier frequency during normal operation. As shown in FIG. 5 , the leakage current can be reduced, and it is possible to prevent the trouble that the leakage automatic circuit breaker operates during the process of energizing the motor in the non-rotating state.

Specifically, it is preferable to set it at approximately 300 Hz or less, so that a leakage current of 1 mA or less, which is a leakage standard of the Electrical Appliance Safety Act, can be realized.

In the above description, the processing of the flowchart shown in FIG. 4 may be performed when the outdoor unit is powered on, but the processing of the flowchart shown in FIG. 4 may be performed when a compressor operation command is received during normal operation. .

Claims (8)

1. A warm-up operation method of an inverter-driven compressor, wherein the inverter-driven compressor (1) operates an electric motor (11) supplied with output power from an inverter as a driving source, compresses a refrigerant, and then circulates it discharge in the flow path, This warm-up operation method is characterized in that the inverter is operated at a carrier frequency lower than that in normal operation to energize the motor (11) without operating the compressor (1). 2. The warm-up operation method of an inverter-driven compressor according to claim 1, wherein the carrier frequency lower than that in normal operation is lower than the carrier frequency when generating a rated cooling or heating capacity. 3. The preheating operation method of the variable frequency drive compressor according to claim 1, characterized in that the carrier frequency lower than normal operation is lower than the carrier frequency when generating 1/2 of the rated capacity of cooling or heating carrier frequency. 4. The warm-up operation method of an inverter-driven compressor according to claim 1, wherein the carrier frequency lower than that during normal operation is lower than the highest carrier frequency when the compressor speed is between 10rps and 120rps frequency. 5. A warm-up operation device for an inverter-driven compressor, the inverter-driven compressor (1) operates an electric motor (11) supplied with output power from an inverter as a driving source, compresses a refrigerant, and then circulates it discharge in the flow path, The warm-up operation device is characterized in that it has an energization control means for energizing the motor (11) by operating the inverter at a carrier frequency lower than that during normal operation without operating the compressor (1). . 6. The warm-up operation device for an inverter-driven compressor according to claim 5, wherein the carrier frequency lower than that in normal operation is lower than the carrier frequency when generating rated cooling or heating capacity. 7. The preheating operation device of variable frequency drive compressor according to claim 5, characterized in that the carrier frequency lower than normal operation is lower than the carrier frequency when generating 1/2 of the rated capacity of cooling or heating carrier frequency. 8. The preheating operation device for variable frequency drive compressors according to claim 5, wherein the carrier frequency lower than that during normal operation is lower than the highest carrier frequency when the compressor speed is between 10rps and 120rps frequency.

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