Electric compressor and control method thereof

Abstract

An electric compressor and a control method thereof are provided for reliably preventing damage due to overheating of an inverter unit provided in the electric compressor. [Solution] The system includes a first step including a step of determining the current discharge pressure state of the electric compressor when the air conditioner installed in the vehicle is turned on; a second step of determining the current RPM information, temperature information of the inverter unit, and phase current information of the electric compressor when the discharge pressure corresponds to an overload pressure; a third step of maintaining a high temperature error signal in an on state when the inverter unit is in an overheated state; and a fourth step of determining whether the electric compressor is operating or not based on the discharge pressure of the inverter unit after the high temperature error signal is turned on. The first step further includes a cooling fan operation confirmation step of confirming whether a cooling fan provided in the vehicle is in operation.

Description

[Technical field]

[0001] The present invention relates to an electric compressor and a control method thereof, and more particularly to an electric compressor and a control method thereof for preventing an inverter unit provided in the electric compressor from overheating to a high temperature. [Background technology]

[0002] Generally, compressors used in automotive air conditioning systems draw refrigerant that has completed evaporation from the evaporator, converts it into a high-temperature, high-pressure state that is easy to liquefy, and transmits it to the condenser. Depending on the structure for compressing the refrigerant, there are two types of compressors: a reciprocating type that compresses the refrigerant while reciprocating, and a rotary type that compresses the refrigerant while rotating. The rotary compressor is classified into a mechanical type that is rotated by an engine as a drive source and an electric type that is rotated by a motor as a drive source. When the outside air temperature is low, such as during the change of seasons or in winter, the temperature of the refrigerant drops below its boiling point, and a phase change occurs in which the refrigerant changes from gas to liquid. Because the compressor can compress gaseous refrigerant but cannot compress liquid refrigerant, when liquid refrigerant flows into the compression system, the compression system gradually becomes fatigued due to the resistance of the fluid.

[0003] When liquid compression begins in an air conditioning system compressor, the pressure and enthalpy of the refrigerant rise and the refrigerant changes to a gas phase. The time it takes for this to happen has a significant impact on determining the compressor's durability. Among these, the electric compressor is a compressor having a scroll type compression mechanism, in which a motor and the compression mechanism are connected, and the refrigerant is compressed by driving the motor, and the driving of the motor is controlled by an inverter equipped with a printed circuit board.

[0004] The electric compressor generates heat during operation. The heat is generated continuously during operation, and especially when the compressor is operated under high load conditions, as the rotation speed of the motor increases, more heat is generated in many parts, such as the motor and the inverter, and the temperature of the electric compressor increases significantly. Such an excessive temperature rise in the electric compressor can cause damage to many of the components that make up the electric compressor, so methods such as installing a heat sink on the electric compressor to release heat to the outside to lower the temperature or occasionally stopping the electric compressor to reduce heat generation are used. However, even if the temperature of the electric compressor is lowered through this process, the waste heat is still discarded, resulting in low energy efficiency of the electric compressor.

[0005] In addition, when the electric compressor is driven under high load conditions, the temperature rises rapidly and the driving performance is also affected, resulting in a problem of a decrease in the maximum number of revolutions per minute of the electric compressor, which reduces the performance. The high load conditions referred to here are, for example, a state in which the outside air temperature is kept at a high temperature of about 50°C while the vehicle is stopped, or a state in which the vehicle is parked outdoors and exposed to direct sunlight, but may also include other conditions.

[0006] The air conditioning system installed in the vehicle draws in the refrigerant that has completed evaporation in the evaporator, converts it into a high-temperature, high-pressure state that is easily liquefied, and transfers it to a condenser. The electric compressor generates heat during operation, and the generated heat continues to be generated during operation. In particular, when the electric compressor is operated under high load conditions, as the rotation speed of the motor increases, more heat is generated in many parts, such as the motor and the inverter, and the temperature of the electric compressor increases significantly. Such an excessive temperature rise in the electric compressor can cause damage to many of the components that make up the electric compressor, so methods such as installing a heat sink on the electric compressor to release heat to the outside to lower the temperature or sometimes stopping the electric compressor to reduce heat generation are used.

[0007] As an example, the inverter includes a motor drive circuit and a control unit, and the motor drive circuit may become hot due to heat generation from semiconductor switching elements that configure the circuit. In this case, the high temperature reduces the current control value of the semiconductor elements inside the inverter, and if a current exceeding the control value is applied, the semiconductor elements may be damaged. In addition, since the electric compressor is placed inside the engine compartment, the inverter may become hot due to heat generated by the engine. In order to prevent such inverter overheating, in the past, when the inverter temperature rose above a certain level, the compressor was stopped to protect the inverter until the inverter temperature dropped sufficiently. However, there was still a risk of damage, and measures to address this were required. Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide an electric compressor and a control method thereof for reliably preventing damage due to overheating of an inverter unit provided in the electric compressor. [Means for solving the problem]

[0009] The method for controlling an electric compressor according to the present invention includes a first step including a step of determining a current discharge pressure state of the electric compressor when an air conditioner installed in a vehicle is turned on; a second step of determining current RPM information, temperature information of an inverter unit, and phase current information of the electric compressor when the discharge pressure corresponds to an overload pressure; a third step of maintaining a high temperature error signal in an on state when the inverter unit is in an overheated state; and a fourth step of determining whether the electric compressor is operating or not based on the discharge pressure of the inverter unit after the high temperature error signal is turned on.

[0010] The first step further includes a cooling fan operation confirmation step of confirming whether or not a cooling fan provided in the vehicle is operating. The first step further includes an inverter unit temperature detection step of detecting a current temperature of an inverter unit when the discharge pressure is equal to or lower than an overload pressure.

[0011] The second step includes a revolutions per minute determination step of determining a current revolutions per minute state of the electric compressor, an inverter unit temperature determination step of determining whether or not a temperature of the inverter unit is within a preset overheat temperature range, and a phase current determination step of determining whether or not a phase current of the electric compressor is maintained at or above a certain value.

[0012] The rotation speed determination step corresponds to a case where the electric compressor operates at a rotation speed of 1000 RPM or less. The inverter unit temperature determination step is characterized in that the inverter unit temperature is determined when the temperature of the inverter unit is either higher than an outside air temperature or is maintained at a first temperature or higher. The phase current determination step corresponds to a case where the phase current is maintained at or above a first current value. The second step determines that the inverter unit is in an overheated state when the current rotational speed of the electric compressor corresponds to a low rotational speed, the temperature of the inverter unit is maintained within an overheating temperature range, and the phase currents are all simultaneously maintained above a certain value.

[0013] The third step further includes a step of switching the operation of the electric compressor to a pause state at the same time as the high temperature error signal is turned on. The third step further includes a high temperature error standby step of maintaining a standby state for a first time period after a high temperature error code is generated. After the third step, the fourth step further includes a discharge pressure recheck step of rechecking the discharge pressure after the first time.

[0014] The fourth step is characterized in that, if the discharge pressure continues to be maintained at or above a predetermined pressure even after the discharge pressure recheck is performed, the fourth step moves to a step before the discharge pressure recheck step. The fourth step includes a step of switching a power source of the vehicle to an off state if the discharge pressure continues to be maintained at a predetermined pressure after moving to the discharge pressure reconfirmation step. The fourth step further includes a step of restarting the electric compressor when the discharge pressure is equal to or lower than a predetermined pressure in the discharge pressure recheck step. After the electric compressor is restarted, the process proceeds to the first step, where the discharge pressure state is rechecked.

[0015] Another method of controlling an electric compressor according to the present invention includes a first step including a step of determining a current discharge pressure state of the electric compressor when an air conditioner installed in a vehicle is turned on; a second step of simultaneously determining current RPM information, temperature information of an inverter unit, phase current information, a temperature rise rate of the inverter unit, and accumulated time information of the inverter unit when the discharge pressure corresponds to an overload pressure; a third step of maintaining a high temperature error signal turned on when the inverter unit is in an overheated state; and a fourth step of determining whether the electric compressor is operating or not based on the discharge pressure of the inverter unit after the high temperature error signal is turned on.

[0016] The electric compressor of the present invention includes a compression unit having a compression mechanism that compresses a refrigerant, a motor unit coupled to one side of the compression unit and having a motor for providing driving force to the compression mechanism, an inverter unit coupled to one side of the motor unit and having an inverter for controlling the motor unit, a detection unit that detects the discharge pressure of the compression unit, the rotations per minute, the temperature of the inverter unit, a phase current applied to the compression unit, and a temperature rise rate of the inverter unit, and a control unit that determines an overheating state of the inverter unit by inputting information detected by the detection unit. The control unit determines whether the inverter unit is overheating by simultaneously receiving information on whether a cooling fan provided in the vehicle is operating, together with the information detected by the detection unit. Effect of the Invention

[0017] According to the present invention, in a vehicle equipped with an electric compressor, the inverter unit can be switched to a stopped state before it overheats and burns out, and then the operation can be restarted or stopped depending on the discharge pressure state, thereby improving safety. Also, by inputting the overheating judgment condition of the inverter unit more accurately, it is possible to control the electric compressor before the inverter element is damaged or immediately after the inverter unit is overheated. Furthermore, even when the electric compressor is operating normally or when the inverter unit is operating abnormally due to overheating, durability can be improved by maintaining a constant level of control safety. [Brief description of the drawings]

[0018] [Figure 1] 4 is a flowchart showing a method for controlling the electric compressor according to the present embodiment. [Diagram 2] 2 is an operational flowchart according to FIG. 1. [Diagram 3] 6 is a flowchart showing a method for controlling an electric compressor according to another embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing the temperature rise rate of the inverter unit and the conditions resulting therefrom according to the present embodiment. [Diagram 5] 1 is a perspective view showing an electric compressor according to an embodiment of the present invention; [Figure 6] FIG. 2 is a diagram showing a control unit and a peripheral configuration according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The advantages and features of the present invention, as well as the methods for achieving them, will become apparent from the following detailed description of the embodiments with accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below, but may be realized in various different forms, and the present embodiments are provided merely to complete the disclosure and to fully inform those skilled in the art to which the disclosure pertains, and the present disclosure is only defined by the scope of the claims. The same reference numerals refer to the same components throughout the specification.

[0020] When an element is referred to as being "connected to" or "coupled to" another element, this includes the cases where the element is directly connected to or connected to the other element, or where there are other elements between them. In contrast, when an element is referred to as being "directly connected to" or "directly coupled to" another element, this includes the cases where there are no other elements between them. "And / or" includes each and every combination of one or more of the listed items.

[0021] The terms used in the present specification are for the purpose of describing the embodiments and are not intended to limit the present disclosure. In the present specification, the singular form includes the plural form unless the context requires otherwise. As used in the specification, "comprises / comprising" means that the mentioned components, steps, operations and / or elements do not exclude the presence or addition of one or more other components, steps, operations and / or elements. Although the terms "first", "second" and the like are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used to distinguish one component from another.

[0022] The method for controlling an electric compressor of the present invention will now be described with reference to the drawings. Fig. 1 is a flow chart showing the method for controlling an electric compressor according to the present embodiment, and Fig. 2 is an operation flow chart according to Fig. 1. As shown in Figs. 1 and 2, the method for controlling an electric compressor of the present invention operates under the condition that the cooling of an inverter unit becomes unstable or the cooling fan is not operating due to a refrigerant leak or an insufficient amount of suctioned refrigerant in an air conditioning system installed in a vehicle. In addition, when the electric compressor is operating under conditions where the outside air temperature is maintained at around 50°C and the vehicle is exposed to direct sunlight, this is intended to prevent damage to the inverter elements due to heat generated by the inverter section.

[0023] To this end, the method includes a first step (ST100) including a step (ST110) of determining the current discharge pressure state of the electric compressor when the air conditioner installed in the vehicle is turned on, a second step (ST200) of determining the current RPM information, temperature information of the inverter unit, and phase current information of the electric compressor when the discharge pressure corresponds to an overload pressure, a third step (ST300) of maintaining the ON state of a high temperature error signal when the inverter unit is in an overheated state, and a fourth step (ST400) of determining whether the electric compressor is operating or not based on the discharge pressure of the inverter unit after the high temperature error signal is turned on.

[0024] The first step (ST100) further includes a cooling fan operation confirmation step (ST120) of confirming whether or not a cooling fan provided in the vehicle is operating. When the air conditioning system provided in the vehicle is operating normally, outside air is supplied to a condenser through a cooling fan, and the condenser is cooled to lower the temperature and induce a phase change of the refrigerant.

[0025] When the cooling fan is not operating, no outside air is supplied to the condenser, so cooling to the condenser is stopped and a high temperature state is maintained. The electric compressor changes the phase of the high-temperature, high-pressure gas phase refrigerant discharged from the compressor to a liquid phase refrigerant in the condenser, and switches to a liquid refrigerant on the premise that cooling by the outside air is stably performed. When the cooling fan is not operating, the refrigerant exists in a high-temperature, high-pressure gas state in the condenser, and when the temperature of the electric compressor rises rapidly to a high temperature, the temperature of the inverter unit also rises at the same time. Therefore, whether or not the cooling fan is operating is an important condition for preventing the inverter elements from burning out or breaking down.

[0026] If the discharge pressure is equal to or less than the overload pressure, the method further includes detecting a current temperature of the inverter unit (ST130). The overload pressure is 350 psi as an example, but may be changed according to design conditions. When the electric compressor operates normally, the discharge pressure is not maintained at an overload pressure. However, as described above, when the cooling fan is not operating, the outside air temperature is maintained at about 50°C, and the vehicle is exposed to direct sunlight, the discharge pressure is 350 psi or more, and the current discharge pressure is determined to be an overload pressure.

[0027] If the discharge pressure is equal to or lower than the overload pressure, the current temperature of the inverter unit is detected (ST130) to determine whether or not overheating has occurred. If the temperature of the inverter unit is 125° C. or higher, the high temperature error signal is maintained in the on state (ST132). Also, by determining again whether the temperature and discharge pressure of the inverter unit are actually in an overheated state, it is reconfirmed whether the inverter unit is overheated (ST134). If the inverter temperature is measured below 115°C and the discharge pressure is below 275 psi, the electric compressor is restarted.

[0028] As described above, when the electric compressor operates normally, the discharge pressure and inverter temperature are judged and the electric compressor continues to operate. Conversely, when the discharge pressure is still above 350 psi, this corresponds to the inverter unit overheating and operating abnormally. It is possible to realize logic that prevents malfunction due to overheating of the inverter even when the electric compressor operates abnormally, and this will be described below.

[0029] The second step (ST200) includes a revolutions per minute determination step (ST210) for determining a current revolutions per minute state of the electric compressor when the pressure corresponds to an overload pressure, an inverter unit temperature determination step (ST220) for determining whether the temperature of the inverter unit is within a preset overheat temperature range, and a phase current determination step (ST230) for determining whether a phase current of the electric compressor is maintained at or above a certain value.

[0030] In the present invention, whether or not the electric compressor has overheated is not determined solely from discharge pressure information, but the state of the revolutions per minute of the electric compressor, whether or not the temperature of the inverter section is within the overheating temperature range, and state information of the phase current are all determined simultaneously, making it possible to accurately determine whether or not the inverter elements are actually maintaining an overheated state, preventing burnout of the inverter elements and stabilizing the operation of the electric compressor.

[0031] For example, the RPM determination step ST210 corresponds to a case where the electric compressor operates at a RPM of 1000 RPM or less. The RPM of 1000 RPM corresponds to a case where the electric compressor operates at a low speed while the vehicle is stopped, and the internal pressure and temperature of the electric compressor are high and high. When the electric compressor operates at a revolutions per minute of 1000 RPM, the circulation of the refrigerant is slower than in a normal state, and the cooling efficiency of the inverter unit is relatively reduced. Therefore, when the revolutions per minute are low, the overheating phenomenon of the inverter unit may become even more frequent.

[0032] The inverter unit temperature determination step (ST220) corresponds to a case where the temperature of the inverter unit is either higher than the outside air temperature or is maintained at or above a first temperature. As an example, the first temperature corresponds to a case where the temperature of the inverter unit is 80° C. or higher. When a temperature rise occurs due to self-heating of the inverter unit, the above temperature is determined to be an approaching temperature to an overheated state. In addition, the inverter temperature and the outside air temperature are input to each other and used as information for more accurately determining whether or not overheating has occurred based on the inverter temperature, so that the condition of the electric compressor can be accurately determined and the information can be used as logic for protecting the compressor in the event of abnormal operation.

[0033] The phase current determination step (ST230) corresponds to a case where the phase current is maintained at or above a first current value, and as an example, the first current value corresponds to a case where the phase current is maintained at or above 33 A. The phase current is current applied to three phases U, V, and W to generate torque required for operating the electric compressor, and when the phase current is maintained at or above 33 A, it is determined that the inverter unit is overheating.

[0034] When the current RPM of the electric compressor corresponds to a low RPM, the temperature of the inverter unit is maintained within an overheating temperature range, and the phase currents are all simultaneously maintained above a certain value, it can be determined that the inverter unit has overheated, thereby improving both accuracy and safety. In this way, when the electric compressor is determined to be in an overheated state by satisfying the above-mentioned state conditions under an overload pressure condition (ST300), the high temperature error signal is turned on and the operation of the electric compressor is simultaneously switched to a temporary stop state (ST310).

[0035] If the inverter unit continues to operate in an overheated state, it may break down and the inverter elements may burn out. Therefore, a high temperature error signal is generated and the electric compressor is switched to a temporary stop state to prevent further operation of the inverter unit, thereby preventing burning due to overheating. The third step (ST300) further includes a high temperature error standby step (ST320) in which a standby state is maintained for a first time after a high temperature error code is generated. The high temperature error standby step (ST320) is maintained in a standby state for 15 seconds, for example, during which the operation of the electric compressor is stopped, and the number of times is maintained up to 3.

[0036] In addition, in a fourth step (ST400), the current discharge pressure of the electric compressor is reconfirmed (ST410) after the first time period to confirm whether restarting of the compressor is possible. If the discharge pressure of the electric compressor is 275 psi or more, the discharge pressure of the electric compressor is checked again (ST410), and the discharge pressure is judged again (ST420). For example, the discharge pressure of the electric compressor may temporarily increase and then decrease, making it necessary to check the discharge pressure again. In this embodiment, if the discharge pressure is still 275 psi or higher after rechecking the discharge pressure (ST420), the vehicle power is forcibly turned off (ST430) to prevent the inverter elements from burning out due to overheating of the inverter section.

[0037] In this way, when the vehicle power is turned off, the electric compressor stops operating, cutting off the environment in which the inverter unit may overheat and preventing damage caused by burning out of the inverter elements, thereby stably protecting the expensive electric compressor. When the compressor stops working, the air conditioner will no longer function, so the vehicle must be taken to a repair shop for maintenance. If the discharge pressure is 275 psi or less, the process switches to step (ST440) of restarting the electric compressor, enabling the air conditioner to operate and cooling the interior area of ​​the vehicle. Also, even after the electric compressor is restarted, the discharge pressure is checked again in the same manner as in the first step (ST100) to determine whether the pressure is an overload pressure.

[0038] Another method of controlling an electric compressor according to the present invention will now be described with reference to the drawings. As shown in FIG. 3, the system includes a first step (ST1000) including a step of determining a current discharge pressure state of the electric compressor when the air conditioner installed in the vehicle is turned on, a second step (ST2000) of simultaneously determining current RPM information of the electric compressor, temperature information of the inverter unit, phase current information, temperature rise rate of the inverter unit, and accumulated time information when the discharge pressure corresponds to an overload pressure, a third step (ST3000) of maintaining a high temperature error signal turned on when the inverter unit is in an overheated state, and a fourth step (ST4000) of determining whether the electric compressor is operating or not based on the discharge pressure of the inverter unit after the high temperature error signal turns on.

[0039] The first step (ST1000) is the same as the first embodiment (ST100) described above, so a detailed description will be omitted, and the second step (ST2000) will be described. The second step (ST2000) includes a revolutions per minute determination step (ST2100) for determining the current revolutions per minute state of the electric compressor, an inverter temperature determination step (ST2200) for determining whether the temperature of the inverter is within a preset overheat temperature range, a phase current determination step (ST2300) for determining whether the phase current of the electric compressor is maintained at a certain value or more, and a temperature rise rate and cumulative time of the inverter are simultaneously determined (ST2400) to determine whether the inverter is overheated, and therefore has a difference in that a risk of damage due to a sudden temperature rise of the inverter can be more accurately determined. The RPM determination step (ST2100) corresponds to a case where the electric compressor operates at a RPM of 1000 RPM or less. The RPM of 1000 RPM corresponds to a case where the electric compressor operates at a low speed when the vehicle is stopped, and where the internal pressure and temperature of the electric compressor are high and high.

[0040] When the electric compressor operates at a revolutions per minute of 1000 RPM, the circulation of the refrigerant is reduced compared to normal conditions, and the cooling efficiency of the inverter unit is relatively reduced. Therefore, when the revolutions per minute are low, the overheating phenomenon of the inverter unit may become more frequent.

[0041] The inverter unit temperature determination step (ST2200) may correspond to either a temperature of the inverter unit being higher than an outside temperature or being maintained at or above a first temperature, and the first temperature corresponds to a temperature being maintained at or above 80° C. When a temperature rise occurs due to self-heating of the inverter unit, the inverter unit determines the above temperature as an entry temperature into an overheated state. In addition, the inverter temperature and the outside air temperature are input to each other and used as information for more accurately determining whether or not overheating has occurred based on the inverter temperature, so that the condition of the electric compressor can be accurately determined, and this can be used as logic for protecting the compressor in the event of abnormal operation.

[0042] The phase current determination step (ST2300) corresponds to a case where the phase current is maintained at or above a first current value, and as an example, the first current value corresponds to a case where the phase current is maintained at or above 33 A. The phase current is applied to three phases U, V, and W to generate torque required for operating the electric compressor, and when the phase current is maintained at or above 33 A, it is determined that the inverter unit is overheating. The current RPM of the electric compressor corresponds to a low RPM, the temperature of the inverter unit is maintained within an overheating temperature range, and the phase current is maintained at or above a certain value, and the temperature rise rate and cumulative time of the inverter unit are also determined to determine whether the inverter unit is overheating, thereby improving both accuracy and safety.

[0043] Regarding the temperature rise rate and cumulative time of the inverter unit, when the temperature rise rate and cumulative time of the inverter unit correspond to cases 1 to 3 attached in FIG. 4, it can be determined that the inverter unit is in an overheated state. As an example, even if the case corresponds to Case 1, if the accumulated time is less than the time shown in the drawing or the temperature of the inverter unit is less than 120°C, the inverter unit is determined to be in a pre-overheated state. In this way, by adding the temperature rise rate and accumulated time information to the judgment of whether the inverter unit is overheating, along with the discharge pressure information of the electric compressor, it is possible to accurately judge whether the electric compressor is operating normally or abnormally, and control is immediately performed accordingly, thereby minimizing the occurrence of breakdowns in the electric compressor.

[0044] Hereinafter, an electric compressor according to the present invention will be described with reference to the drawings. 5 and 6, the refrigerant ...

[0045] The control unit 5 determines whether the inverter unit 1 is overheating or not by simultaneously receiving the information detected by the detection unit 4 and whether or not a cooling fan provided in the vehicle is operating.

[0046] The detection unit 4 includes a first detection unit 4a that detects the discharge pressure of the compression unit 3, a second detection unit 4b that detects the revolutions per minute of the compression unit 3, a third detection unit 4c that detects the temperature of the inverter unit 1, a fourth detection unit 4d that detects the phase current applied to the compression unit 3, and a fifth detection unit 4e that detects the rate of temperature rise of the inverter unit 1. The control unit 5, in addition to controlling the motor unit 2, receives information detected by the first to fifth detection units 4a, 4b, 4c, 4d, and 4e, and can accurately determine whether the inverter unit 1 is overheating or not, thereby preventing the electric compressor from breaking down. When the electric compressor operates under normal conditions, the control unit 5 compares preset data with the information input by the detection unit 4 to accurately determine whether the inverter unit 1 is overheating.

[0047] The present invention has been described above, but a person having ordinary knowledge in the relevant technical field can modify and change the present invention in various ways by adding, changing, deleting or adding elements without departing from the concept of the present invention as described in the claims, and this can also be said to be within the scope of the claims of the present invention. [Industrial Applicability]

[0048] The present invention can prevent overheating of the inverter section and achieve stable operation of the electric compressor.

Claims

1. A first step includes a step of determining a current discharge pressure state of an electric compressor in a state where an air conditioner installed in a vehicle is turned on; a second step of determining current revolutions per minute information of the electric compressor, temperature information of an inverter unit, and phase current information when the discharge pressure corresponds to an overload pressure; a third step of maintaining a high temperature error signal in an on state when the inverter unit is in an overheated state; and a fourth step of determining whether the electric compressor is operating or not based on a discharge pressure of the inverter unit after the high temperature error signal is turned on.

2. 2. The method of claim 1, wherein the first step further comprises a cooling fan operation confirmation step of confirming whether a cooling fan provided in the vehicle is in operation.

3. 2. The method according to claim 1, wherein the first step further comprises an inverter unit temperature detection step of detecting a current temperature of an inverter unit when the discharge pressure is equal to or lower than an overload pressure.

4. the second step includes a step of determining a current state of the rotational speed per minute of the electric compressor; an inverter unit temperature determination step of determining whether or not the temperature of the inverter unit is within a preset overheat temperature range; 2. The method for controlling an electric compressor according to claim 1, further comprising a phase current determining step of determining whether or not a phase current of the electric compressor is maintained at a constant value or more.

5. 5. The method for controlling an electric compressor according to claim 4, wherein the step of determining the revolutions per minute corresponds to a case where the electric compressor is operated at a revolutions per minute of 1000 RPM or less.

6. 5. The control method for an electric compressor according to claim 4, wherein the inverter unit temperature determination step is performed when the temperature of the inverter unit is either higher than an outside air temperature or is maintained at or above a first temperature.

7. 5. The method according to claim 4, wherein the phase current determining step corresponds to a case where the phase current is maintained at a first current value or more.

8. 5. The method of claim 4, wherein the second step determines that the inverter unit is in an overheated state when a current rotational speed of the electric compressor corresponds to a low rotational speed, a temperature of the inverter unit is maintained within an overheating temperature range, and all of the phase currents are simultaneously maintained at or above a certain value.

9. 2. The method of claim 1, wherein the third step further comprises the step of temporarily suspending the operation of the electric compressor when the high temperature error signal is turned on.

10. 10. The method of claim 9, wherein the third step further comprises a high temperature error standby step of maintaining a standby state for a first time period after a high temperature error code is generated.

11. 11. The method according to claim 10, wherein the fourth step, which is performed after the third step, further comprises a discharge pressure recheck step of rechecking the discharge pressure after the first time period.

12. 12. The method for controlling an electric compressor according to claim 11, wherein the fourth step is performed before the discharge pressure re-check step if the discharge pressure continues to be maintained at or above the predetermined pressure even after the discharge pressure re-check is performed.

13. 13. The method for controlling an electric compressor according to claim 12, wherein the fourth step includes a step of switching a power source of the vehicle to an off state if the discharge pressure continues to be maintained at a predetermined pressure after moving to the discharge pressure re-check step.

14. 12. The method according to claim 11, wherein the fourth step further comprises the step of restarting the electric compressor when the discharge pressure recheck step determines that the discharge pressure is equal to or lower than a predetermined pressure.

15. 15. The method for controlling an electric compressor according to claim 14, wherein after the electric compressor is restarted, the method proceeds to the first step, in which a discharge pressure state is reconfirmed.

16. A first step includes a step of determining a current discharge pressure state of an electric compressor in a state where an air conditioner installed in a vehicle is turned on; a second step of simultaneously determining current revolutions per minute information of the electric compressor, temperature information of an inverter unit, phase current information, a temperature rise rate of the inverter unit, and accumulated time information when the discharge pressure corresponds to an overload pressure; a third step of maintaining a high temperature error signal in an on state when the inverter unit is in an overheated state; and a fourth step of determining whether the electric compressor is operating or not based on a discharge pressure of the inverter unit after the high temperature error signal is turned on.

17. a compression unit including a compression mechanism for compressing a refrigerant; a motor unit including a motor coupled to one side of the compression unit to provide a driving force to the compression mechanism; an inverter unit coupled to one side of the motor unit and including an inverter for controlling the motor unit; a detection unit that detects a discharge pressure of the compression unit, a revolution speed per minute, a temperature of the inverter unit, a phase current applied to the compression unit, and a temperature rise rate of the inverter unit; a control unit that determines an overheating state of the inverter unit by receiving information detected by the detection unit, An electric compressor, which is controlled by the method for controlling an electric compressor according to any one of claims 1 to 16.

18. 18. The electric compressor according to claim 17, wherein the control unit determines whether the inverter unit is overheating by simultaneously receiving information on whether a cooling fan installed in a vehicle is operating together with the information detected by the detection unit.

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