Electrical compression device

Abstract

The present invention relates to an electrical compression device (1) comprising: an electric motor (9); a high-voltage capacitor (25); a compression member (8) driven by the electric motor (9); and a control board (19) that comprises an inverter (24) intended to deliver an electric current to the electric motor (9) and a control unit (23) for controlling the inverter (24), the electric compression device (1) comprising a high-voltage connector (16) that provides the power to be supplied to the electric motor (9) and a low-voltage connector (18), the control board (19) comprising a control device (28) configured to verify an electrical connection of the high-voltage connector (16), characterised in that the control device (28) is supplied with electric power coming from the high-voltage connector (16).

Description

[0001] Electric compression device

[0002] The present invention relates to the field of electric compressors, and more particularly to means of discharging certain internal electrical components of these electric compressors.

[0003] Typically, motor vehicles are equipped with electric compressors integrated into air conditioning systems to condition the air sent into the vehicle's passenger compartment. To achieve this, the electric compressor compresses a refrigerant fluid that circulates in a closed loop within the air conditioning system.

[0004] The electric compressor typically consists of a housing into which the refrigerant enters at low pressure. The refrigerant circulates within the housing where it is compressed, and then it is expelled from the housing at high pressure. To accomplish this, the housing contains, among other things, a compression unit configured to compress the refrigerant, an electric motor configured to drive the compression unit, and an inverter configured to power the electric motor by supplying it with electrical energy.

[0005] The electric compressor is powered by a battery, to which it is connected via a connector. Therefore, when the connector is disconnected, the power supply is interrupted. However, there is a risk of electric shock due to the high residual voltage stored within the electric compressor, which necessitates a waiting period before an operator can safely handle it.

[0006] To solve this problem, it is known in the prior art to use a means of discharging the residual voltage stored in the electric compressor. This discharge method reduces the waiting time required before the electric compressor can be used safely, for example, from one minute to a few seconds.

[0007] The discharge method can be a passive discharge, for example, which involves using one or more resistors whose values ​​correspond to the desired discharge time and the amount of energy to be discharged. These resistors are connected to the positive terminal of a high-voltage connector on the electric compressor, allowing for continuous discharge. However, using a passive discharge method that induces continuous discharge results in losses, as the discharge occurs even when the electric compressor is in standby mode.

[0008] The discharge method can alternatively be an active discharge, which detects a disconnection of the connector and activates a switch within a predefined time to initiate the discharge. However, this active discharge is dependent on a low-voltage power supply and therefore cannot be implemented without such a supply.

[0009] The present invention falls within this context by proposing an electric compressor in which the discharge means is supplied with high voltage, thus allowing the use of the discharge means even in the absence of low voltage supply.

[0010] The main object of the present invention is an electric compression device comprising an electric motor, a high-voltage capacitor, a compression element driven by the electric motor, and an electric motor control board. The control board includes at least one inverter for supplying electric current to the electric motor and an inverter control unit. The electric compression device includes a high-voltage connector that supplies power to the electric motor and a low-voltage connector that supplies power to the control unit. The control board includes a monitoring device configured to verify an electrical connection of the high-voltage connector. According to the invention, the monitoring device is powered by electrical energy from the high-voltage connector.

[0011] The electric compression device according to the invention is intended for use in a motor vehicle, integrated within the vehicle's air conditioning or treatment system. The electric compression device comprises a compression element designed to compress a refrigerant circulating within the device in order to increase its pressure. The compression element is connected to an electric motor that drives its rotation. This electric motor is itself indirectly powered from a high-voltage connector on the electric compression device, which connects it to an electrical power source. More specifically, the high-voltage connector supplies high-voltage alternating current to an inverter, which converts this alternating current into direct current to power the electric motor.The ultimate role of the high-voltage connector is to supply power to the electric motor. In parallel with the high-voltage connector, the electrical compression device includes a low-voltage connector that provides control signals, notably to an inverter control unit. The role of the high-voltage connector is therefore to send control signals, particularly for power supply or diagnostic purposes.

[0012] The high voltage connector operates at voltages of at least 400 V, for example a voltage of 800 V, while the low voltage connector operates at voltages below 48 V, for example a voltage of 12 V or 24 V.

[0013] Within the inverter, the electric motor receives a portion of the electrical energy via one or more high-voltage capacitors, whose role is to phase-shift the electrical energy. These capacitors thus participate in the transformation of alternating current into direct current.

[0014] To be operable by an operator, the electrical compression device must discharge rapidly when the high-voltage connector is disconnected. It is particularly important to discharge the capacitor(s) that store electrical energy at high voltage and are susceptible to electric shock. The electrical compression device includes a control device that makes the capacitor discharge contingent upon physical separation of the power source from the compression device, particularly when the high-voltage connector is disconnected. The control device is powered from the high-voltage connector, so the capacitor discharge can be initiated even in the absence of low voltage, such as due to a fault, a break in electrical continuity, or disconnection of the low-voltage connector.This control device is, for example, a locking device or interlock in English.

[0015] According to one feature of the invention, the control device is independent of any external control, as well as of any control by the control unit, for example a microcontroller.

[0016] According to an optional feature of the invention, the electrical compression device includes a voltage reducer configured to receive the high voltage from the high-voltage connector and to deliver electrical power to the control device. The voltage reducer is interposed on the control board between the high-voltage connector and the control device. The voltage reducer provides a voltage value suitable for the operation of the control device. Such a suitable voltage value for the operation of the control device is, for example, on the order of 6 V.

[0017] According to an optional feature of the invention, the electrical compression device includes a high voltage determination device comprising at least one electrical resistance, the voltage reducer comprising at least one electrical resistance, the electrical resistance of the determination device and / or the electrical resistance of the voltage reducer forming a discharge resistance of the high voltage capacitance.

[0018] The high-voltage determination device measures and / or calculates high voltage; it therefore includes one or more sensors. The high-voltage determination device may be integrated into the control unit or be separate from it.

[0019] Each step-down transformer and high-voltage detection device includes at least one electrical resistor. Either the electrical resistor of the step-down transformer acts as a discharge resistor for the high-voltage capacitor, or the electrical resistor of the high-voltage detection device acts as a discharge resistor for the high-voltage capacitor, or both the electrical resistor of the step-down transformer and the electrical resistor of the high-voltage detection device act as discharge resistors for the high-voltage capacitor. The discharge resistor, when it corresponds to the electrical resistance of the high-voltage detection device, is the component that provides passive discharge of the high-voltage capacitor.

[0020] Using an electrical resistor in the high-voltage determination device to discharge the capacitance reduces the number of components required in the electrical compression device, and therefore its overall cost. Such an electrical resistor is often pre-existing in prior art electrical compression devices where the control device is powered from the low-voltage connector. Similarly, using an electrical resistor in the step-down transformer to discharge the capacitance also helps to reduce the cost of the electrical compression device, since an existing resistor within the transformer is used for discharge purposes, rather than adding a separate resistor specifically dedicated to discharge within the electrical compression device.

[0021] According to an optional feature of the invention, the electrical compression device includes a discharge switch capable of taking an open position and a closed position in which the high-voltage capacitance is discharged.

[0022] The discharge switch is controlled by the control device. It allows for active discharge of the high-voltage capacitor. In the open position of the discharge switch, no current flows and discharge is impossible. Conversely, in the closed position, current flows and the high-voltage capacitor is discharged by current flowing through the discharge resistor. Using a discharge switch improves efficiency because discharge occurs only when needed; thus, there is no continuous current dissipation. The discharge switch is, for example, an insulated-gate bipolar transistor, also known as an IGBT module.

[0023] The invention also relates to a motor vehicle comprising an electrical harness equipped with at least one connecting element and an electrical compression device as previously mentioned, the connecting element being connected to the high-voltage connector.

[0024] The wiring harness is a cable that is part of the vehicle and is connected to the high-voltage connector of the electric compressor via a connecting element. Thus, the high-voltage connector and the connecting element are complementary in form. The wiring harness carries high-voltage electrical energy from the power source to the compressor.

[0025] In parallel with the connecting device, the motor vehicle includes a branch device which is complementary to the low voltage connector.

[0026] When the connecting device and the high-voltage connector are engaged, the high-voltage capacitance is not discharged. Conversely, when the high-voltage connector is disconnected from the connecting device, the high-voltage capacitance is discharged. This discharge occurs independently of the state of the low-voltage connector, that is, regardless of whether it is connected to the connecting device or not.

[0027] The invention further relates to a method of discharging an electrical compression device as previously mentioned, comprising a step of verifying the connection state of the high-voltage connector, a step of passively discharging the high-voltage capacitance and a step of actively discharging the high-voltage capacitance.

[0028] The discharge method according to the invention is designed to discharge the high-voltage capacitor, which stores electrical energy within the electrical compression device, for the purpose of safely handling this electrical compression device. This safe handling is possible, for example, when the voltage across the high-voltage connector is below 60 V.

[0029] The discharge process comprises both a passive discharge stage and an active discharge stage of the high-voltage capacitor. The high-voltage capacitor discharge stages are contingent upon a verification stage of the high-voltage connector's connection status, which is performed by the control device.

[0030] Apart from the aforementioned discharge steps, the discharge process is independent of any external control, as well as any control by the control unit in particular.

[0031] According to an optional feature of the invention, the passive discharge step is implemented when the high-voltage connector is disconnected.

[0032] In other words, the passive discharge stage is implemented when the vehicle's connection device is disconnected from the high-voltage connector. The passive discharge stage is implemented prior to the active discharge stage. This allows for a reduction in the size of the components involved in the active discharge, which operate at a lower voltage since the high-voltage capacity has already been partially discharged.

[0033] According to an optional feature of the invention, the active discharge step is implemented upon obtaining a determined high voltage threshold.

[0034] The high-voltage threshold therefore corresponds to a voltage value below which the active discharge stage is implemented, this voltage value being obtained through the passive discharge of the high-voltage capacitor. The attainment of the high-voltage threshold is verified by the high-voltage determination device. According to an optional feature of the invention, the passive discharge stage involves the electrical resistance of the high-voltage determination device.

[0035] In addition, the active discharge stage involves the electrical resistance of the voltage reducer.

[0036] According to an optional feature of the invention, to implement the active discharge step, the discharge switch moves from its open position to its closed position.

[0037] According to an optional feature of the invention, the discharge steps are independent of a supply of electrical energy through the low voltage connector.

[0038] In other words, the discharge of the high-voltage capacitance is permitted even in the absence of low voltage within the electrical compression device.

[0039] Other features, details and advantages of the invention will become clearer upon reading the following description on the one hand, and the illustrative and non-limiting examples of embodiments given with reference to the accompanying drawings on the other hand, in which:

[0040] [Fig. 1] illustrates, schematically, the general organization of an electrical compression device according to the invention;

[0041] [Fig. 2] is a simplified electrical diagram of the electric compression device according to the invention.

[0042] The features, variations, and different embodiments of the invention may be combined in various ways, provided they are not incompatible or mutually exclusive. In particular, variations of the invention may be conceived comprising only a selection of features, described hereafter in isolation from the other described features, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from the prior art.

[0043] In the figures, elements common to several figures retain the same reference.

[0044] Figure 1 schematically illustrates an electric compression device 1 according to the present invention, which is intended, for example, to be integrated into the air conditioning system of a motor vehicle, so as to treat an airflow circulating within the passenger compartment of that motor vehicle. The airflow is, for example, treated using a refrigerant circulating within the electric compression device 1.

[0045] The electric compression device 1 comprises a housing 2, here generally cylindrical in shape, which is closed by a cover 3. The housing 2 of the electric compression device 1 can be made of aluminum or an aluminum alloy. This housing 2 of the electric compression device 1 can, for example, be composed of several parts manufactured separately and then joined together. Alternatively, the housing 2 can be made from a single piece, this single piece being obtained, for example, by molding.

[0046] The housing 2 delimits at least one cavity 4 and a housing 5 separated from each other by an internal wall 6 of the housing 2. As shown in Figure 1, the cavity 4 houses a control module 7, while the housing 5 receives a compression element 8 and a motorization, in this case an electric motor 9.

[0047] As illustrated, the housing 2 also includes an inlet 10 and an outlet 11 configured to allow the refrigerant to enter and exit the housing 2, respectively. More specifically, this inlet 10 and outlet 11 are located in a portion of the housing 2 that defines the compartment 5, which houses the compressor 8 and the electric motor 9. The housing 2 is therefore configured so that the refrigerant circulates at least along the electric motor 8, notably to cool it. This refrigerant thus circulates in the compartment 5, where it is compressed by the compressor 9, which is driven in rotation by a drive shaft 12 of the electric motor 8.

[0048] The compression element 9 can, for example, be a spiral compression mechanism, one spiral of which is fixed while the other spiral oscillates. When the electric compression device 1 is integrated into a closed circuit of an air conditioning system as described above, the refrigerant leaves the electric compression device 1 after being compressed by the compression element 9 to reach, for example, a condenser.

[0049] The electric motor 8 is electrically powered and controlled via the control module 7 housed in cavity 4 of the housing 2 of the electric compression device 1. This control module 7 is powered by a wiring harness 13, which is a cable electrically connected to a power supply of the motor vehicle in which the electric compression device 1 is mounted, for example, the vehicle's electrical system. The vehicle's power supply to which the wiring harness 13 is connected is a high-voltage power supply.

[0050] According to the example illustrated in Figure 1, the electrical harness 13 includes, at one of its longitudinal ends, a connection member 14 opposite the cover 3 of the housing 2. This connection member 14 includes a female element 15 to which the electrical power harness 13 is connected. The connection member 14 is here engaged with a high-voltage connector 16 protruding from the cover 3 of the housing 2. This high-voltage connector 16 includes a male element 17 which is inserted into the female element 15 at one end and is also connected to the control module 17.

[0051] In addition to the high-voltage connector 16, the electrical compression device 1 includes a low-voltage connector 18, which is also connected to the control module 7. Although not shown here, this low-voltage connector 18 is also connected to the vehicle's electrical system, specifically to a low-voltage power supply. "Low voltage" here refers to an electrical voltage below 48 V, such as 12 V, and "high voltage" refers to an electrical voltage of 400 V or higher, such as 800 V.

[0052] The control module 7 will now be described in detail in relation to Figure 2, on which it is shown outside the housing 2. This control module 7 includes a control board 19 of the electric motor 9, which is an electronic board on which are fixed a plurality of electronic components which participate directly or indirectly in the compression of the refrigerant.

[0053] The control board 19 is here divided into two zones, with a low voltage zone 20 in which at least the low voltage connector 18 is located and a high voltage zone 21 in which at least the high voltage connector 16 is located. The low voltage zone 20 and the high voltage zone 21 are separated by an electrical insulator 22, a delimitation between this low voltage zone 20 and this high voltage zone 21 being illustrated in figure 2 in the form of a dotted line.

[0054] The control card 19 includes a control unit 23, which is powered from the low voltage connector 18. More specifically, from the electrical energy supplied to it by the low voltage connector 18, this control unit 23 is capable of sending control signals in particular to an inverter 24 of the electric compression device 1, or to a component of the vehicle external to the electric compression device 1 according to the invention.

[0055] The inverter 24 is located in the high-voltage zone 21 and is supplied with high voltage from the high-voltage connector 16. This high voltage, which is distributed as alternating current to the inverter 24, is converted by the inverter 24 into direct current to be supplied to the electric motor 9. It is therefore understood from the above that the electric motor 9 is supplied with high-voltage direct current from the high-voltage alternating current supplied to the electric compression device 1 by the high-voltage connector 16.

[0056] Electrical energy can be supplied to the electric motor 9 from a high-voltage capacitor 25 of the inverter 24, whose role is to participate in the conversion of alternating current into direct current within the electrical compression device 1. The high-voltage capacitor 25 is shown here as being carried by the control board 19, but different embodiments could also be considered in which this high-voltage capacitor 25 would be disposed outside the control board 19, i.e. within another area of ​​the control module 7. Similarly, although only one high-voltage capacitor 25 is shown here, other embodiments of the electrical compression device 1 could include a plurality of high-voltage capacitors 25.

[0057] Within the electric compression device 1, the voltage is measured and / or calculated using a high-voltage determination device 26. This high-voltage determination device 26 includes at least one electrical resistor, which is a voltage measuring resistor 27. Generally, the high-voltage determination device 26 is used to read the voltage within the electric compression device 1 during the operation of the compression member 8. The high-voltage determination device 26 is also used to determine whether the voltage of the electric compression device is sufficiently low for it to be safely operated by a motor vehicle operator.The voltage value must be checked, in particular, when the high-voltage connector 16 is disconnected, that is, when the connection point 14 of the vehicle's electrical harness 13 is detached from the high-voltage connector 16. It is then especially important to check the voltage across the high-voltage capacitor 25. The voltage measured across the high-voltage capacitor 25 is a high-voltage direct current (HVDC) voltage. In this context of disconnecting the high-voltage connector 16, if the measured voltage exceeds a threshold value, the high-voltage capacitor 25 must be discharged.

[0058] For this purpose, the control board 19 includes a control device 28 configured to verify an electrical connection of the high-voltage connector 16; in other words, it is configured to verify whether the connecting element 14 is physically plugged into the high-voltage connector 16. Within the high-voltage connector 16, the connecting element 14 is, for example, connected to the control device 28 via at least two pins. When the pins connect the connecting element 14 to the control device 28, the control device 28 sends a connection signal, for example, to the control unit 23.Conversely, when the pins are disconnected, that is, when the connecting member 14 is separated from the control device 28 located within the high voltage connector 16, the control device 28 sends a disconnection information which leads to the implementation of the discharge process of the high voltage capacitor 25.

[0059] As shown in Figure 1, the control device 28 is located in the high-voltage zone 21. The control device 28 is also intended to be powered by the electrical energy from the high-voltage connector 16. As mentioned previously, the high-voltage connector operates at voltage values ​​above 400 V; however, the control device 28 operates at lower voltage values. In order to adapt to the operating voltage of the control device 28, the control module 7 includes a step-down converter 29. This step-down converter 29 is electrically located between the high-voltage connector 16 and the control device 28; "electrically located" here means that it is powered by the high voltage from the high-voltage connector 16, from which it in turn supplies the control device 28.The voltage reducer 29 allows the voltage supplied by the high voltage connector 16 to be reduced to a value compatible with the operation of the control device 28, for example a voltage of around 6 V.

[0060] The control device 28 is independent of any external control, as well as any control by the control unit 28. The control unit 28 can be, for example, a microcontroller. The step-down converter 29 includes at least one electrical resistor, or step-down converter resistor 30, which can contribute to the discharge of the high-voltage capacitor 25. Similarly, the voltage measuring resistor 27 can be used to discharge the high-voltage capacitor 25.

[0061] In addition to the voltage measuring resistors and the voltage reducer 27, 30, the high-voltage capacitor 25 is discharged using a discharge switch 31, for example, an IGBT module (insulated-gate bipolar transistor). This discharge switch 31 is controlled by the control device 28. Thus, the discharge switch 31 is capable of assuming either an open position, as illustrated in Figure 2, or a closed position, the transition from one position to the other being governed by the control device 28. Discharge of the high-voltage capacitor 25 is permitted in the closed position of the discharge switch 31. Such a discharge of the high-voltage capacitor 25 will now be described with respect to a method of discharging the electrical compression device 1 according to the invention.

[0062] As previously mentioned, the discharge process ensures that the electrical compression device 1 can be handled safely, particularly once it has been disconnected from the vehicle's electrical harness 13. The discharge process therefore includes a first step of verifying the connection status of the high-voltage connector 16, during which the control device 28 checks whether the connecting element 14 is physically plugged into the high-voltage connector 16 or is disconnected from it. If the control device 28 detects that the connecting element 14 is connected to the high-voltage connector 16, the discharge of the high-voltage capacitor 25 is not initiated.

[0063] Conversely, if the control device 28 detects a separation of the connecting member 14 from the high-voltage connector 16, the control device 28 sends the disconnection information to the control unit 23 and the discharge process continues with at least one passive discharge stage.

[0064] This passive discharge stage is characterized by the discharge of the high-voltage capacitor 25 using the voltage measuring resistor 27. During the passive discharge stage, the voltage measured across the high-voltage capacitor 25 decreases. Current flows through an electrical loop that includes the voltage measuring resistor 27; the current is converted into heat, and the voltage drops. This voltage value is then measured by the high-voltage determining device 26. When the high-voltage determining device 26 determines that the measured voltage value is below a predetermined threshold value, an active discharge stage of the discharge process is initiated.

[0065] It is therefore understood that in order to be implemented, the active discharge step requires on the one hand the verification of the separation between the connecting element 14 and the high voltage connector 16, and on the other hand the discharge through the voltage measuring resistor 27 until the voltage value measured across the terminals of the high voltage capacitance 25 is less than the predetermined threshold value.

[0066] The active discharge stage corresponds to an instruction from the control device 28 that commands the discharge switch 31 to move from its open position to its closed position. In the closed position of the discharge switch 31, electrical energy flows through it and reaches the resistor of the step-down resistor 30, for example. The discharge of the high-voltage capacitor 25 via the resistor of the step-down resistor 30 is then carried out, dissipating the heat generated at the resistor of the step-down resistor 30. Of course, this active discharge operation can also use a resistor other than the resistor of the step-down resistor 30, in particular a resistor dedicated to the discharge function.

[0067] This active discharge step is implemented until a voltage value deemed safe is obtained, measured by the high voltage determination device 26, for example a voltage value below 60 V.

[0068] The present invention thus proposes an electrical compression device in which the discharge of a high voltage capacitance is possible even in the absence of low voltage supply, such a discharge combining both a passive discharge and an active discharge.

[0069] The present invention is not limited to the means and configurations described and illustrated herein, and also extends to any equivalent means and configuration as well as any technically operative combination of such means.

Claims

DEMANDS 1. Electric compression device (1) comprising an electric motor (9), a high voltage capacitor (25), a compression member (8) driven by the electric motor (9), and a control board (19) for the electric motor (9), the control board (19) comprising at least one inverter (24) for delivering an electric current to the electric motor (9) and a control unit (23) for the inverter (24), the electric compression device (1) comprising a high voltage connector (16) that supplies the power supply to the electric motor (9) and a low voltage connector (18) that supplies the electrical power to the control unit (23), the control board (19) comprising a control device (28) configured to check an electrical connection of the high voltage connector (16), characterized in that the control device (28) is supplied with electrical power from the high voltage connector (16).

2. Electric compression device (1) according to the preceding claim, the control device (28) being independent of any external control, as well as of any control by the control unit (23).

3. Electrical compression device (1) according to the preceding claim, comprising a voltage reducer (29) configured to receive the high voltage from the high voltage connector (16) and to deliver the electrical energy to the control device (28).

4. Electrical compression device (1) according to the preceding claim, comprising a high voltage determination device (26) which includes at least one electrical resistance (27), the voltage reducer (29) comprising at least one electrical resistance (30), the electrical resistance (27) of the determination device and / or the electrical resistance (30) of the voltage reducer (29) forming a discharge resistance of the high voltage capacitor (25).

5. Electrical compression device (1) according to any one of the preceding claims, comprising a discharge switch (31) capable of taking an open position and a closed position in which the high voltage capacitance (25) is discharged.

6. Motor vehicle comprising an electrical wiring harness equipped with at least one connection element (14) and an electrical compression device (1) according to one of any of the preceding claims, the connecting member (14) being connected to the high voltage connector (16).

7. A method for discharging an electrical compression device (1) according to any one of claims 1 to 5, comprising a step of verifying the connection status of the high-voltage connector (16), a step of passively discharging the high-voltage capacitor (25), and a step of actively discharging the high-voltage capacitor. (25).

8. Discharge method according to the preceding claim, wherein the passive discharge step is implemented when the high-voltage connector (16) is disconnected.

9. Discharge method according to any one of claims 7 and 8, wherein the active discharge step is implemented upon obtaining a determined high voltage threshold.

10. A discharge method according to any one of claims 7 to 9 in combination with claim 4, wherein the passive discharge step involves the electrical resistance (27) of the high-voltage determination device (26).

11. Discharge method according to any one of claims 7 to 10 in combination with claim 5, wherein to implement the active discharge step the discharge switch (31) moves from its open position to its closed position.

12. Discharge method according to any one of claims 7 to 11, wherein the discharge steps are independent of a supply of electrical energy through the low voltage connector (18).

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