KR102195809B1 - Control method of electrically powered - Google Patents

Abstract

The present invention relates to a control method of an electric compressor, wherein when a user operates an air conditioner, applying power to a temperature controller that controls temperature (S100), designating a rotation speed of a driving motor (S200), and a compressor Starting (S300), determining whether the compressor is in a normal starting state after starting (S400), and if the compressor is in a normal starting state, driving the compressor (S500), In step S400, if the compressor is not in a normal starting state, determining whether to start the compressor (S450), and restarting the compressor after the determination (S470). According to the present invention, when the compressor is turned off, the load applied to the drive motor immediately before the turn off is calculated, and the compressor is restarted after having a waiting time for lowering the load to a minimum, thereby restarting in an advantageous condition with a small load. Therefore, it is effective to reduce the probability of restart failure and reduce the risk of damage to scrolls or inverters through stable restart.

Description

Control method of electrically powered}

The present invention relates to a control method of an electric compressor, and more particularly, to a control method of an electric compressor capable of applying an optimal motor restart waiting time according to the starting condition of the compressor.

In general, compressors applied to air conditioning systems take in refrigerant gas that has passed through an evaporator, compress it into a high-temperature, high-pressure refrigerant gas state, and discharge it to a condenser, and various types of compressors such as reciprocating, rotary, scrolling, and swash plate types are available. Is being used.

Among these compressors, a compressor that uses an electric motor as a power source is generally referred to as an electric compressor, and as an example of an electric compressor, a scroll type compressor among electric compressors is disclosed in Korean Patent Registration No. 10-0882481.

In general, an electric compressor is provided with an inverter that controls the electric motor, such as adjusting the number of rotations of the electric motor in order to variably adjust the cooling efficiency of the air conditioner when the external load condition changes.

The inverter includes a circuit board on which various circuit elements are mounted, and is accommodated in an inverter housing provided on one side of a housing of a compressor and sealed through a cover.

Conventional electric compressors guarantee stability only by turning on/off the clutch in case of abnormal operation such as failure, disconnection, or overheating, or by determining the abnormal operation by the inverter at the initial start of the compressor, waiting for a certain period of time, and restarting the compressor. A method to ensure stability was used.

However, it is very inefficient to restart the compressor after simply giving a waiting time without reflecting the starting conditions such as suction pressure, discharge pressure, DC current value or RPM information at the initial start of the compressor. In addition, if the waiting time is not sufficient, there is still a risk of damage to parts such as scrolls or inverters, and thus another method is required to ensure the stability of the compressor.

Korean Patent Registration No. 10-0882481 (Registration date 2009. 02. 02)

An object of the present invention is to provide a control method of an electric compressor capable of applying an optimum waiting time for restarting a motor according to a starting condition of the compressor.

The control method of the electric compressor of the present invention includes the steps of applying power to a temperature controller that controls temperature when the user operates the air conditioner (S100), designating the number of rotations of the driving motor (S200), and starting the compressor. Step S300, determining whether the compressor is in a normal starting state after starting the compressor (S400), and if the compressor is in a normal starting state, driving the compressor normally (S500), the S400 In the step, if the compressor is not in a normal starting state, determining whether to start the compressor (S450), and restarting the compressor after the determination (S470).

The step of determining whether to start the compressor (S450) is an information storage step (S451) of measuring and storing rotation speed (RPM) information, DC current value, and discharge pressure information of the electric motor immediately before the electric motor is turned off (S451). ) May be further included.

After the information storing step (S), the step of comparing the RPM information with the previously stored DC current value reference table for each RPM (S452) and comparing the DC current value (S453) may be further included.

The step of comparing the discharge pressure value with a suction-side pressure value reference table according to a DC current value for each discharge pressure value stored in advance (S454) may be further included.

The step of deriving an expected suction pressure value according to the discharge pressure value, DC current value, and RPM value (S455) may be further included.

The step of matching the waiting time corresponding to the expected suction pressure value from the previously stored reference waiting time table (S456) may be further included.

It is preferable to further include applying the matched waiting time (S457), and restarting the compressor after applying the waiting time (S470).

In the control method of an electric compressor according to an embodiment of the present invention, when the motor of the compressor is turned off for a normal or abnormal reason, an optimal motor restart waiting time can be applied according to the starting condition of the compressor at the time of the off, so that the probability of restarting the compressor Can be reduced. Accordingly, it is possible to stably restart the compressor, thereby reducing the risk of component damage.

1 is a flow chart showing a control method of an electric compressor according to an embodiment of the present invention.
FIG. 2 is a detailed flowchart illustrating main steps according to the control method of the electric compressor of FIG. 1.

Hereinafter, a method for controlling an electric compressor according to an embodiment of the present invention will be described in detail with reference to the drawings.

1 is a flowchart illustrating a method of controlling an electric compressor according to an exemplary embodiment of the present invention, and FIG. 2 is a flowchart illustrating in detail main steps according to the method of controlling the electric compressor of FIG. 1.

The control method of an electric compressor according to an embodiment of the present invention can be applied to all general electric compressors, and a basic electric compressor configuration will be described briefly.

The compressor is provided with a housing forming an exterior, and a drive motor for driving the compressor is installed inside the housing. An inverter housing and a cover are provided on one side of the housing of the compressor, and an inverter for controlling the driving motor is installed inside the inverter housing to be electrically connected to the driving motor.

The driving motor drives the compression unit provided in the housing of the compressor, and the inverter adjusts the discharge amount of the refrigerant by variably adjusting the rotation speed of the driving motor.

In general, the inverter is composed of a circuit board on which various circuit elements such as a controller including an IC in which an inverter operation program is stored, an intelligent power module having a motor drive function, a regulator, an inductor, and a capacitor are mounted.

In addition to controlling the drive motor, the inverter also serves to determine restarting or starting failure of the electric compressor when the drive motor is turned off for normal or abnormal reasons.

As shown in FIGS. 1 and 2, the control method of the electric compressor according to an embodiment of the present invention is performed in an inverter, and hereinafter, the subject of control and determination should be understood as an inverter, even if there is no separate mention ( Since the on/off of the compressor is performed by the drive motor, the off of the compressor is used interchangeably with the off of the drive motor).

First, when the user operates the air conditioner (S100), the inverter applies power to the temperature controller that controls the temperature. Thereafter, the rotation speed of the drive motor is designated so that the temperature set by the user can be realized (S200) and the compressor is started (S300).

Next, it is determined whether the compressor is in a normal starting state (S400), and if the compressor is normally starting, the compressor is normally driven (S500). If the compressor is not in a normal starting state, a step (S450) of determining whether the compressor is started is entered.

The step of determining whether to start the compressor (S450) refers to the off state of the compressor, and stores information on the RPM information, DC current value, and discharge pressure information of the electric motor just before the off state (S451), and By reflecting in the control algorithm, it is determined whether or not the compressor is restarted.

Reflecting this information is to give a waiting time for proper restart according to the load by determining whether the load immediately before the electric motor is turned off is above a certain level, regardless of whether the electric motor is normally turned off or turned off due to an error.

Taking the scroll type electric compressor as an example, the size of the load applied to the drive motor may be different depending on the suction side pressure condition even under the same discharge pressure condition. In general, when the refrigerant suction side pressure is high, a large load is applied, and a larger amount of current flows to maintain the speed.

The suction and discharge pressures start at normal pressure at the initial start of the compressor, and the pressure difference increases during the operation of the compressor, and the discharge pressure increases. In this case, when restarting immediately after the electric compressor is turned off, even if the same discharge pressure value is shown, the value of the suction pressure may be different depending on the environment of the vehicle, and the load applied to the driving motor may vary.

When a high load is applied to the drive motor, the probability of failure to start the compressor increases significantly, and continued failure to start may cause damage to components such as scrolls and inverters.

However, the suction side pressure of the electric compressor does not have a separate pressure sensor, so its state cannot be known. However, the suction side pressure value according to the discharge side pressure value can be experimentally predicted from the DC current value sensed before off. That is, if a pressure sensor that measures the suction side pressure is provided and the DC current value is different for each discharge side pressure value through an experiment, the suction side pressure by DC current value for the discharge side pressure as a reference is measured by measuring the corresponding suction side pressure value. You can create a table of values. This suction-side pressure table may be stored in advance in the inverter, and the load applied to the drive motor can be calculated by calculating the suction-side pressure value according to the DC current value and the discharge-side pressure value immediately before the drive motor is turned off using this reference table. .

On the other hand, when the driving motor is turned off in a situation where the rotational speed of the driving motor is high, the DC current value immediately before turning off may appear large. To this end, the RPM of the driving motor can also be applied as one variable, and a DC current value table for each RPM as a reference can be obtained by measuring the DC current value for each various RPM through an experiment. The created DC current value table for each RPM can be stored in the inverter in advance.

When the reference table is defined in the above-described way, the restart waiting time suitable for the discharge side pressure value and the DC current value per RPM can be defined in advance, and this defined waiting time can also be created as a reference waiting time table and stored in the inverter. have.

Based on these defined reference values, when the drive motor is turned off, the load immediately before off is determined, and a short waiting time is given for a low load and a long waiting time is provided for a high load, so that the compressor can be restarted under favorable conditions when the load is lowered when restarting do.

As shown in FIG. 2, the step of determining whether the compressor is started (S450) stores RPM information, DC current value, and pressure value information on the refrigerant discharge side of the driving motor just before the compressor is turned off (S451). The stored RPM information of the driving motor immediately before the compressor is turned off, the DC current value, and the refrigerant discharge-side pressure value information are compared with a reference table (S452 to S454), and a suction-side pressure value is calculated through the reference table (S455).

When the suction side pressure value is calculated, a restart waiting time suitable for the calculated suction side pressure value is found and matched from the reference table (S456), and the matched reference waiting time is applied (S457) to wait for restart of the compressor. After the waiting time elapses, the compressor is attempted to restart (S470).

For example, if the RPM of the drive motor before off is between 2500rpm and the DC current value is 2.5A at that time, it can be seen that the expected suction pressure in the following reference table is 3~4bar. At this time, since the restart waiting time is preferably 2 seconds, it is preferable to give the waiting time of 2 seconds and then attempt to restart the drive motor.

Motor RPM DC current value (A) Discharge side pressure (bar) prediction
Suction side pressure (bar) Waiting time(s) 1000~2000 0~1 5-6 2~3 One 2000~3000 1~2 6~7 3~4 2 ... ... ... ... ... 7000~8000 6~7 11~12 8~9 10 8000~9000 7~8 12~13 9-10 15

Through such a method, when the compressor is turned off, the load applied to the drive motor immediately before the turn off is calculated, and the compressor is restarted after a waiting time for lowering the load to a minimum, thereby restarting in an advantageous condition with a small load. Therefore, it is effective to reduce the probability of restart failure and reduce the risk of damage to scrolls or inverters through stable restart.

One embodiment of the present invention described above and illustrated in the drawings should not be construed as limiting the technical idea of the present invention. The scope of the present invention is limited only by the matters described in the claims, and those of ordinary skill in the technical field of the present invention can improve and change the technical idea of the present invention in various forms. Therefore, as long as these improvements and changes are apparent to those of ordinary skill, they will fall within the scope of the present invention.

Claims (7)

When the user operates the air conditioner, applying power to a temperature controller that controls the temperature (S100),
Designating the number of revolutions of the drive motor (S200),
Starting the compressor (S300) and,
Determining whether the compressor is in a normal starting state after starting the compressor (S400),
If the compressor is in a normal starting state, including the step of normally driving the compressor (S500),
If the compressor is not in a normal starting state in step S400, determining whether to start the compressor (S450);
Further comprising the step (S470) of restarting the compressor after the judgment,
The step of determining whether to start the compressor (S450) is an information storage step (S451) of measuring and storing rotation speed (RPM) information, DC current value, and discharge pressure information of the electric motor immediately before the electric motor is turned off (S451). ), the control method of the electric compressor further comprising. delete The method of claim 1,
Comparing the RPM information with a DC current value reference table for each RPM stored in advance after the information storing step (S451) (S452), and comparing the DC current value (S453). . The method of claim 3,
Comparing the discharge pressure value with a suction-side pressure value reference table according to a DC current value for each discharge pressure value stored in advance (S454). The method of claim 4,
The method of controlling an electric compressor further comprising the step of deriving an expected suction pressure value according to the discharge pressure value, DC current value, and RPM value (S455). The method of claim 5,
Matching the waiting time corresponding to the expected suction pressure value from the reference waiting time table stored in advance (S456). The method of claim 6,
The method further comprises applying the matched waiting time (S457), and restarting the compressor (S470) after applying the waiting time.

Images