JP2013212000A - Electric compressor - Google Patents

Abstract

An object of the present invention is to suppress the deterioration of an electrolytic capacitor and increase the life of an electric compressor by boosting the pressure in consideration of the lifetime of the electrolytic capacitor provided in the inverter.
A boosting unit 101 boosts a DC voltage from a battery 50 at a predetermined boosting rate. The inverter 102 includes an electrolytic capacitor 111 that smoothes the DC voltage boosted by the booster 101, converts the DC voltage smoothed by the electrolytic capacitor 111 into an AC voltage, and supplies the AC voltage to the motor 103. The life estimation unit 106 estimates the life of the electrolytic capacitor 111. The step-up rate setting unit 107 controls the input current to the inverter 102 by controlling the step-up rate of the step-up unit 101 according to the estimated lifetime of the electrolytic capacitor 111.
[Selection] Figure 1

Description

  The present invention relates to an electric compressor that compresses refrigerant by receiving power supply and driving a motor.

  Conventionally, the drive device of the electric compressor for motor vehicles of patent documents 1 is known. The drive device of Patent Document 1 includes an electric compressor with a built-in motor, an inverter that energizes the motor of the electric compressor to drive the electric compressor at a variable rotational speed, a battery that is a power supply to the inverter, A boosting unit that boosts the DC voltage of the battery, a load detection unit that detects a load, and a control device that controls the boosting unit based on an output value and a load determination value of the load detection unit.

  Thus, in Patent Document 1, the voltage supplied to the inverter is variably controlled by the control device to reduce the operating current of the electric compressor, and the electric compressor is operated with high efficiency for a wide air conditioning load. Can do.

JP 2003-25834 A

  However, in Patent Document 1, since the boosting means is controlled by paying attention to the operating efficiency, the boosting rate in the boosting means is improved in order to improve the operating efficiency when the remaining life of the electrolytic capacitor provided in the inverter is small. If the input current of the inverter is increased by reducing the voltage, the deterioration of the electrolytic capacitor is accelerated and the life of the electric compressor is shortened.

  An object of the present invention is to provide an electric compressor that can suppress deterioration of the electrolytic capacitor and increase the life of the electric compressor by boosting in consideration of the life of the electrolytic capacitor provided in the inverter. It is to be.

  An electric compressor according to the present invention is an electric compressor that compresses refrigerant by receiving power supply and driving a motor, the boosting unit boosting a DC voltage from the power source at a predetermined boosting rate, and the boosting unit Having an electrolytic capacitor for smoothing the DC voltage boosted by the inverter, converting the DC voltage smoothed by the electrolytic capacitor to an AC voltage and supplying the motor, and estimating the remaining life of the electrolytic capacitor, And a control unit that controls the boosting rate of the boosting unit according to the remaining life of the electrolytic capacitor.

  According to the present invention, by raising the voltage in consideration of the life of the electrolytic capacitor provided in the inverter, deterioration of the electrolytic capacitor can be suppressed, and the life of the electric compressor can be extended.

The figure which shows the structure of the electric compressor in embodiment of this invention The flowchart which shows operation | movement of the electric compressor which concerns on embodiment of this invention. The figure which shows the relationship between the pressure | voltage rise rate and the lifetime of an electrolytic capacitor in embodiment of this invention The figure which shows the relationship between the pressure | voltage rise rate and efficiency of a pressure | voltage rise part in embodiment of this invention

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment)
<Configuration of electric compressor>
The configuration of the electric compressor 100 according to the embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing a configuration of an electric compressor 100 according to the present embodiment. In FIG. 1, the battery 50 and the notification unit 108 are also shown together with the electric compressor 100.

  The electric compressor 100 mainly includes a booster 101, an inverter 102, a motor 103, a temperature detector 104, a load detector 105, a life estimation unit 106, and a booster rate setting unit 107. Control device 150 includes a temperature detection unit 104, a load detection unit 105, a life estimation unit 106, and a boost rate setting unit 107.

  The boosting unit 101 boosts a DC voltage supplied from the battery 50 as a power source at a predetermined boosting rate and supplies it to the inverter 102 under the control of a boosting rate setting unit 107 described later. The booster 101 boosts the voltage by changing the storage time when power is stored in the coil L1 in accordance with the boost rate set by the boost rate setting unit 107. When a certain predetermined power is output from the inverter 102, the voltage output from the booster 101 becomes higher as the boost rate in the booster 101 is increased, and as a result, the input current of the inverter 102 can be reduced.

  Inverter 102 includes an electrolytic capacitor 111, a switching element 112, and a shunt resistor 113. The electrolytic capacitor 111 smoothes the DC voltage supplied from the booster 101. The inverter 102 converts the DC voltage smoothed by the electrolytic capacitor 111 into an AC voltage by the switching element 112 and supplies the AC voltage to the motor 103.

  The motor 103 is driven by being supplied with an AC voltage from the inverter 102 and compresses the refrigerant.

  The temperature detection unit 104 detects the temperature around the electrolytic capacitor 111. The temperature detection unit 104 outputs the detection result of the detected temperature to the life estimation unit 106. The temperature detection unit 104 detects the temperature around the electrolytic capacitor 111 using, for example, a thermistor.

  The load detection unit 105 detects a load accompanying driving of the motor 103. Here, the load is a motor current applied to the motor 103. The load detection unit 105 detects the motor current based on the voltage value of the shunt resistor 113 provided in the inverter 102. The load detection unit 105 calculates the value of the direct current applied to the electrolytic capacitor 111 based on the detected motor current, and outputs the calculation result to the life estimation unit 106.

  The lifetime estimation unit 106 estimates the lifetime of the electrolytic capacitor 111 based on the calculation result of the DC current value input from the load detection unit 105 and the detection result of the temperature input from the temperature detection unit 104, and the estimation result is obtained. Output to the step-up rate setting unit 107. When the remaining life of the electrolytic capacitor 111 (hereinafter referred to as “remaining life”) is equal to or less than the threshold, the life estimation unit 106 informs the notification unit 108 of information indicating that the remaining life of the electrolytic capacitor 111 is low. Take control. The life estimation unit 106 estimates the life of the electrolytic capacitor 111 according to, for example, Arrhenius' law law. Here, the remaining life of the electrolytic capacitor 111 is the remaining time until the electrolytic capacitor 111 does not perform a predetermined function. The remaining lifetime of the electrolytic capacitor 111 can be obtained by subtracting the lifetime from the lifetime of the electrolytic capacitor 111, for example. For example, a technique disclosed in Japanese Patent Application Laid-Open No. 2006-166669 may be applied to the processing of the load detection unit 105 and the life estimation unit 106 here.

  The step-up rate setting unit 107 controls the step-up rate by setting the step-up rate of the step-up unit 101 in accordance with the life estimation result input from the life estimation unit 106. The step-up rate setting unit 107 controls the step-up unit 101 so as to step up at the set step-up rate. As a result of controlling the step-up rate, the input current of the inverter 102 can be controlled.

  The notification unit 108 notifies information indicating that the remaining life of the electrolytic capacitor 111 is low according to the control of the life estimation unit 106. The notification unit 108 notifies information indicating that the remaining life of the electrolytic capacitor 111 is short by display, sound, light, or the like.

<Operation of electric compressor>
The operation of the electric compressor 100 according to the embodiment of the present invention will be described with reference to FIG. FIG. 2 is a flowchart showing the operation of the electric compressor 100 according to the present embodiment.

  First, the electric compressor 100 is activated (step ST201).

  Next, the load detection unit 105 detects a load (step ST202).

  Next, the temperature detection unit 104 detects the temperature around the electrolytic capacitor 111 (step ST203).

  Next, the lifetime estimation unit 106 estimates the remaining lifetime of the electrolytic capacitor 111 based on the detected load and the detected temperature around the electrolytic capacitor 111 (step ST204).

  Next, the step-up rate setting unit 107 determines whether or not the estimated remaining life is greater than a threshold (step ST205).

  When the estimated remaining life is greater than the threshold (step ST205: YES), the boost rate setting unit 107 sets the boost rate α (step ST206), and controls the boost unit 101 to boost at the boost rate α. .

  On the other hand, when the estimated remaining life is equal to or less than the threshold (step ST205: NO), the boost rate setting unit 107 sets a boost rate β (α <β) larger than the boost rate α (step ST207), and the boost rate The booster 101 is controlled so as to boost by β. As a result, when the estimated remaining life is less than or equal to the threshold, the input current of the inverter 102 can be reduced compared to when the estimated remaining life is greater than the threshold.

  Moreover, the alerting | reporting part 108 alert | reports the information that there is little remaining life of the electrolytic capacitor 111 (step ST208).

<Relationship between boost rate and electrolytic capacitor life>
The relationship between the step-up rate and the remaining life of the electrolytic capacitor 111 in the embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a diagram showing the relationship between the step-up rate and the remaining life of the electrolytic capacitor 111 in the present embodiment. FIG. 4 is a diagram illustrating the relationship between the boosting rate and the efficiency of the boosting unit 101.

  3, FIG. 3A is a diagram showing the relationship between the boost rate and time, and FIG. 3B is a diagram showing the relationship between the remaining life and time. 3A and 3B, the solid line indicates a conventional example in which the life of the electrolytic capacitor 111 is not considered, and the broken line indicates the present embodiment in which the life of the electrolytic capacitor 111 is considered. In FIGS. 3A and 3B, the solid line and the broken line overlap each other before the time when the broken line branches from the solid line.

  From FIG. 3, when the remaining life of the electrolytic capacitor 111 is equal to or less than the threshold value, the boosting rate in the boosting unit 101 is increased as compared with the case where the remaining life of the electrolytic capacitor 111 is greater than the threshold value. The lifetime can be extended.

  In addition, as shown in FIG. 3, the step-up rate setting unit 107 may increase the step-up rate stepwise as the remaining life of the electrolytic capacitor 111 decreases.

  Also, as shown in FIG. 4, the efficiency of the booster 101 decreases as the boost rate is increased. Therefore, it is preferable that the step-up rate setting unit 107 sets a step-up rate that can achieve both the maintenance of the life of the electrolytic capacitor 111 and the efficiency of the step-up unit 101.

<Effects of the present embodiment>
According to the present embodiment, by raising the voltage in consideration of the life of the electrolytic capacitor provided in the inverter, deterioration of the electrolytic capacitor can be suppressed, and the life of the electric compressor can be extended.

  In addition, according to the present embodiment, while increasing the boosting rate of the boosting unit, while notifying that the remaining life of the electrolytic capacitor is small, before the electrolytic capacitor is deteriorated and the electric compressor cannot be used, The user can replace the electrolytic capacitor.

<Modification of the present embodiment>
In the present embodiment, the remaining lifetime of the electrolytic capacitor and the threshold value are compared. However, the present invention is not limited to this, and the lifetime of the electrolytic capacitor and the threshold value may be compared.

  The electric compressor according to the present invention is suitable for compressing refrigerant by receiving power supply and driving a motor.

DESCRIPTION OF SYMBOLS 50 Battery 100 Electric compressor 101 Booster part 102 Inverter 103 Motor 104 Temperature detection part 105 Load detection part 106 Life estimation part 107 Boosting rate setting part 108 Notification part 111 Electrolytic capacitor 112 Switching element 113 Shunt resistance 150 Control apparatus

Claims (4)

An electric compressor that compresses refrigerant by driving a motor in response to power supply,
A boosting unit that boosts a DC voltage from the power source at a predetermined boosting rate;
An electrolytic capacitor that smoothes the DC voltage boosted by the boosting unit, and converts the DC voltage smoothed by the electrolytic capacitor into an AC voltage and supplies the AC voltage to the motor;
A controller that estimates a remaining life of the electrolytic capacitor and controls a boosting rate of the boosting unit according to the remaining life of the electrolytic capacitor;
An electric compressor. A temperature detection unit for detecting a temperature around the electrolytic capacitor;
The controller is
The electric compressor according to claim 1, wherein a direct current value applied to the electrolytic capacitor is calculated, and a remaining life of the electrolytic capacitor is estimated based on the direct current value and the temperature detected by the temperature detection unit. The controller is
The electric compressor according to claim 1, wherein when the estimated remaining life of the electrolytic capacitor is less than a threshold, the boosting rate of the boosting unit is set larger than when the estimated remaining life of the electrolytic capacitor is equal to or greater than the threshold. The electric compressor according to claim 1, further comprising a notification unit that notifies information indicating that a remaining life of the electrolytic capacitor is less than a threshold value.

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