DE102017222446A1 - Electric drive device for driving a hybrid electric / electric vehicle, hybrid electric / electric vehicle - Google Patents

Abstract

Disclosed is an electric drive device (AV) for driving a hybrid electric / electric vehicle, comprising: - at least two (power) electrical arrangements (EM, ST, VS, GT, LE) with parasitic capacitance, each having an electromagnetic shielding unit (SK, UM, SB), an electrically conductive cooling unit (KK) and / or an electrically conductive mechanical protection unit (MG), - wherein the shielding units (SK, UM, SB), the cooling units (KK) and / or the protection units (MG) via low-impedance connections (NV) are electrically connected to each other and have a common electrical connection point (AP), - a series circuit (RS) of a resistor (R) and a coil (SD), wherein the series circuit (RS) the connection point (AP) electrically connected to vehicle mass (KL31) of the hybrid electric / electric vehicle.

Description

Technical area:

The present invention relates to an electric drive device for driving a hybrid electric / electric vehicle and a hybrid electric / electric vehicle with said drive device.

State of the art and object of the invention:

In electric mobility, electric drive devices are demanding ever higher drive power, dynamics and ever higher torque. This higher requirement and the associated dimensioning and geometry of the drive devices result in correspondingly increasing parasitic capacities of the drive devices. High parasitic capacitances in turn lead to high common mode currents (common mode currents), which can cause disturbances and even failures in the drive devices.

Thus, the object of the invention is to optimize an electrical drive arrangement with respect to the systemic parasitic capacitances cost.

Description of the invention:

This object is solved by subject matters of the independent claims. Advantageous embodiments are the subject of the dependent claims.

According to a first aspect of the invention, an electric drive arrangement for driving a hybrid electric / electric vehicle is provided.

The drive device comprises at least two (power) electrical arrangements, which due to construction and function have parasitic capacities or components with parasitic capacitances. Each of the assemblies includes one or more components having parasitic capacitances, including electromagnetic shielding units, electrically conductive cooling units, and / or electrically conductive mechanical protection units.

The drive device further comprises low-impedance connections, via which all of the components with parasitic capacitances, that is to say all shielding units, all electrically conductive cooling units and / or all electrically conductive protection units, are connected to one another electrically and with low impedance. The components with parasitic capacitances, namely the shielding units, the cooling units and / or the protective units as well as the low-impedance connections also have a (single) common electrical connection point.

The drive device further comprises a series circuit of a resistor and a coil, wherein the series connection electrically connects the common connection point with vehicle ground (that is, a ground connection) of the hybrid electric / electric vehicle.

The invention is based on the idea that the parasitic capacitances in the drive device are in particular caused by capacitive coverings of the shielding units, the electrically conductive cooling units and / or the electrically conductive protective units of the drive device and by capacitive coverings of the electrical leads between these components. Due to the parasitic capacitances during rapid switching operations (of current / voltage transformers of the drive device) during operation of the drive device capacitive Umladeströme arise as disturbing common mode currents (common mode currents).

Are these components with the capacitive pads (directly and individually) with the vehicle mass (vehicle body or metallic structure of the vehicle, according to the industry standard designation as "terminal 31 (KL31)" electrically contacted, so form circuits over the vehicle mass, through which can flow the common mode currents and cause disturbances and failures in the drive device.

In the context of the invention, it has also been recognized that a so-called common mode equipotential structure (common mode equipotential structure) or common mode equipotential surface can be created by a low-impedance connection of the components to the capacitive pads.

By forming the common mode equipotential structure, the capacitive transient currents can be idealized only in a single common electrical connection point (a so-called common-mode equipotential point).

This single common connection point is then electrically connected to the vehicle ground via a series connection of a resistor and a coil. In this case, the series circuit has an impedance which is esp. Higher than the sum of impedances of all low-impedance connections between the shielding units, the cooling units and the protection units.

It is important that the common mode equipotential structure is electrically connected exclusively by means of the common common-mode equipotential connection point and via said series circuit with the vehicle ground and otherwise from both the vehicle mass and all other electrically conductive components of the drive device or the Vehicle is completely electrically isolated.

By introducing the common mode equipotential structure with the common common mode equipotential terminal, the unwanted capacitive recharging currents in the common mode equipotential terminal coincide. Further, the Umladeströme be suppressed by the (relatively high impedance) series connection. As a result, the charge transfer currents can no longer propagate in the drive device or even beyond the drive device.

In this case, the inductance of the coil in particular represents a high impedance for high-frequency signals, so that the common-mode equipotential structure for high-frequency current components of the capacitive recharging currents is decoupled from the vehicle ground. As a result, none of the high-frequency current components mentioned can propagate via the vehicle mass to the other components of the drive device or of the vehicle.

By this measure, no circuit on the vehicle mass can be stimulated more. The vehicle body with the vehicle mass is therefore no longer a circuit that can implement the disturbing Umladeströme or the associated disruptive recharging energy.

In order to achieve the optimum result, as many as possible, in particular all, components of the drive device which have capacitive pads and thus can generate interfering common-mode currents during operation of the drive device, should be electrically connected to one another via the low-impedance connections. These components include esp. The electrically conductive shielding units, the electrically conductive cooling units and the electrically conductive protective units of the drive device.

In addition, the components with capacitive coverings, that is to say the shielding units, the cooling units and / or the protective units, should in particular be designed in such a way that the geometrical extent of the low-impedance connections can be made as compact as possible.

The solution described above for suppressing capacitive Umladeströmen (or common mode currents) with the common mode equipotential structure with the (single) common common mode equipotential connection point, as well as the series connection of a resistor and a coil has over a solution with expensive filter elements significant cost advantage.

Electromagnetic interference emission and high power losses, which occur in the solution with the filter elements are largely avoided or reduced with the solution described above.

In order for the drive assembly is optimized in terms of systemic parasitic capacitances cost.

For example. have the low-impedance connections in a frequency range of up to 10 KHz (kilohertz) together and a total resistive resistance of less than 500 μΩ (micro-ohms) or between 220 to 500 μΩ.

Furthermore, the low-impedance connections, for example, together in a frequency range of up to 1 GHz (Giga heart) and a total insertion loss of less than 6 dB (decibels).

For example. the series connection has a total resistance of less than 100 milliohms, or between 50 to 100 milliohms, or between 80 to 100 milliohms.

Furthermore, the series circuit has, for example, a total inductance value of less than 1000 μH, or less than 900 μH, or less than 800 μH.

For example. the series connection comprises a protective conductor choke (for example as the aforementioned coil).

For example. The at least two arrangements comprise an electric motor, a power electronics circuit for operating the electric motor, a gate driver circuit for operating the power electronics circuit and / or electrical connections between the aforementioned arrangements.

The power electronics circuit for operating the electric motor includes, for example, an inverter for providing phase currents for the electric motor and / or a rectifier for converting phase currents of the electric motor into a direct current.

For example. the shielding units comprise at least one shielding plate for the electromagnetic shielding of the power electronics circuit and / or the gate driver circuit, at least one shield contact of the electrical connections and / or at least one sheathing of the electrical connections, in particular a phase plug and / or a phase current busbar.

For example. The cooling units comprise at least one electrically conductive heat sink for cooling the electric motor and / or the power electronics circuit.

For example. The protective units comprise at least one electrically conductive housing part of the electric motor, the power electronics circuit and / or the gate driver circuit.

For example. The low-impedance connections comprise at least one metal or metal alloy sheet, in particular copper or a copper alloy, which is connected, in particular soldered or welded, to the shielding units, the cooling units and / or the protective units in a low-impedance manner.

For example. For example, the low impedance connections comprise a braid of carbon fibers having a metal embedded in the carbon fiber or a metal alloy, esp. copper or a copper alloy embedded in the carbon fiber, which is low impedance connected to all of the shielding units, the cooling units and / or the protection units. Esp. The braid covers all of the shielding units, the cooling units and / or the protective units and is connected to them in a low-impedance manner, for example soldered or welded.

The drive device further includes, for example, a link capacitor, which in turn has parasitic capacitances. The parasitic capacitances are directly electrically connected to the low-impedance connections. Otherwise, the DC link capacitor or its two (negative and positive) electrodes are electrically insulated from the low-impedance connections.

The drive device further includes, for example, a high-voltage battery and / or a control circuit for controlling the power electronics circuit and / or the gate driver circuit. The high-voltage battery and the control circuit including the shielding units, their cooling units and / or their protection units (if they are available) are electrically shielded by the shielding units, cooling units, protective units of the aforementioned components with capacitive coverings and said low-impedance connections except for the ground contact via the vehicle ground completely isolated.

According to another aspect of the invention, a hybrid electric / electric vehicle is provided.

The hybrid electric / electric vehicle includes a vehicle body which is referred to as vehicle ground ("chassis ground", with terminal name). KL31 ") Serves.

The hybrid electric / electric vehicle further comprises a drive device described above, wherein the drive device is electrically connected via the series circuit directly to the vehicle ground.

Advantageous embodiments of the drive device described above are, as far as possible, transferable to the above-mentioned hybrid electric / electric vehicle, to be regarded as advantageous embodiments of the hybrid electric / electric vehicle.

list of figures

• 1 in einer schematischen Darstellung eine elektrische Antriebsvorrichtung AV für ein Elektrofahrzeug gemäß einer Ausführungsform der Erfindung;
• 2 in einer weiteren schematischen Darstellung eine elektrische Antriebsvorrichtung AV für ein Elektrofahrzeug gemäß einer weiteren Ausführungsform der Erfindung.

In the following, exemplary embodiments of the invention are explained in more detail with reference to the accompanying drawings. Showing:

• 1 in a schematic representation of an electric drive device AV for an electric vehicle according to an embodiment of the invention;
• 2 in a further schematic representation of an electric drive device AV for an electric vehicle according to another embodiment of the invention.

Detailed description of the drawing:

• - einen Elektromotor EM zum Antrieb des Elektrofahrzeugs;
• - eine Traktionsbatterie BT zum Bereitstellen von Strom für den Elektromotor EM;
• - eine Leistungselektronikschaltung LE mit Transistorschaltern zum Umwandeln des von der Traktionsbatterie BT bereitgestellten Gleichstromes in Phasenströme für den Elektromotor EM;
• - eine Gate-Treiberschaltung GT zum Betreiben der Leistungselektronikschaltung LE bzw. deren Transistorschalter;
• - eine Steuerschaltung SE zum Steuern der Gate-Treiberschaltung GT und der Leistungselektronikschaltung LE.

In the 1 illustrated drive device AV includes:

• - an electric motor EM to drive the electric vehicle;
• - a traction battery BT for providing power to the electric motor EM ;
• - A power electronics circuit LE with transistor switches for converting the from the traction battery BT provided direct current into phase currents for the electric motor EM ;
• a gate driver circuit GT for operating the power electronics circuit LE or their transistor switch;
• a control circuit SE for controlling the gate driver circuit GT and the power electronics circuit LE ,

The drive device AV further comprises an intermediate circuit capacitor ZK for reducing voltage fluctuations in the drive device AV ,

In addition, the drive device comprises AV electrical connections between the aforementioned components, such as. B. traction power lines BL between the traction battery BT and the power electronics circuit LE for forwarding the battery current, a three-phase phase current busbar VS (Leadframe) and a three-phase phase current connector ST between the power electronics circuit LE and the electric motor EM for forwarding the phase currents.

The electric motor EM is formed in this embodiment as a third-excited or permanent-magnet synchronous machine and comprises a housing MG Made of aluminum alloy to protect the electric motor EM , The housing MG includes sections which are used to cool the electric motor EM serve.

The power electronics circuit LE in this embodiment includes an inverter and a DC-DC converter. The inverter is in this embodiment of a B6 Bridge with transistor switches, such. As MOEFEST or IGTB trained. The DC-DC converter is designed in this embodiment as a bidirectional DC-DC converter of known type.

The gate driver circuit GT In this embodiment, it comprises circuit parts for operating the inverter and the DC-DC converter of known type and is in the power electronics circuit LE integrated.

The power electronics circuit LE and the gate driver circuit GT have a common heat sink vs for cooling the power electronics circuit LE and the gate driver circuit GT on, which is formed of an aluminum alloy. Furthermore, the power electronics circuit LE and the gate driver circuit GT shielding SB from an aluminum alloy, which the power electronics circuit LE and the gate driver circuit GT each other or circuit components of the power electronics circuit LE and the gate driver circuit GT shield each other electromagnetically in a manner known to those skilled in the art.

The electrical connections between the power electronics circuit LE and the electric motor EM , namely the phase current busbar VS as well as the phase current connector ST , have shielding contacts SK or sheathing AROUND made of a copper alloy for the electromagnetic shielding of the electrical connections.

Due to the parasitic capacitances in the metallic housing MG , the metallic heat sink KK , in the metallic shielding plates SB , as well as in the metallic shield contacts SK or sheaths AROUND Due to the capacitive deposits of these components arise during operation of the drive device AV with rapid switching capacitive Umladeströme as disturbing common mode currents. With a high drive dynamics and a high drive line common mode currents with a current of 50 amperes up to several hundred amperes can arise.

In order to eliminate these common mode currents and to limit the negative effect of these common mode currents, the drive device comprises AV a braid of carbon fibers with a copper alloy embedded in the carbon fiber which forms the housing MG , the heat sink KK , the shielding plates SB as well as the shield contacts SK as well as the sheathing AROUND spanned all over and connected or welded with these low-dependent. Thus, the network forms low-impedance compounds NV between these components MG . KK . SB . AROUND . SK , where the low-dependent compounds NV by direct, extensively extended physical and electrical contacts of the mesh with these components MG . KK . SB . AROUND . SK are made. This forms the mesh NV a kind of equipotential "enclave" or "wrapping" for the mentioned components MG . KK . SB . AROUND . SK which are the components MG , KK, SB . AROUND , SK of the remaining components of the drive device AV and the vehicle - with the exception of a single, hereinafter to be described electrical connection via a series circuit to be described below - electrically completely isolated.

The DC link capacitor ZK includes parasitic capacities PK (In the figure schematically with a white circular area on the DC link capacitor ZK shown) directly with the braid NV flatly extended low-impedance electrically connected (in the figure schematically shown with a dashed line). The two electrodes of the DC link capacitor ZK are however from the network NV electrically isolated.

The braid NV and the low impedance connections from the mesh NV to all of the components listed above MG . KK , SB, UM, SK, including to parasitic capacities PK of the DC link capacitor ZK together have a total ohmic resistance of between 220 to 500 μΩ in a frequency range of up to 10 KHz. In addition, the braid NV and the low impedance connections from the mesh NV to all components MG . KK . SB . AROUND . SK . PK together in a frequency range of up to 1 GHz overall, a total insertion loss of less than 6 dB.

The braid NV has an electrical connection point AP which, as a common common-mode equipotential, connects to a single electrical connection between the braid to be described below NV and the vehicle mass KL31 serves.

The drive device AV further comprises the aforementioned series connection RS from a resistance R and a coil SD where the coil SD is executed in this embodiment as a protective conductor choke. The series connection RS represents the only, previously mentioned electrical connection from the mesh NV or from the common common-mode equipotential connection point AP to the vehicle mass KL31 ago. That's the braid NV and thus also the components MG . KK . SB . AROUND . SK . PK solely and solely via this common common mode equipotential connection point AP and further via the series connection RS with the vehicle mass KL31 electrically connected.

In this case, the inductance of the coil SD or the series connection RS Especially for high-frequency signals, a high impedance, so the braid NV including all components MG . KK . SB . AROUND . SK . PK for high-frequency current components of the capacitive Umladeströme of the vehicle mass KL31 is decoupled and thus none of these high-frequency current components on the vehicle mass KL31 in the components of the drive device AV and / or the vehicle and there may cause disturbances and even failures.

Esp. indicates the series connection RS one compared to the total impedance of the mesh NV higher total impedance. Specifically, the series circuit RS has a total resistance value of between 80 to 100 milliohms. Furthermore, the series circuit RS has a total inductance value of less than 1000 μH.

The unwanted capacitive Umladeströme during operation of the drive device AV in the above components MG . KK . SB . AROUND . SK . PK arise, accumulate over the low-impedance connections of the mesh NV at the common mode equipotential terminal AP together.

The low impedance version of the common mode equipotential structure of the mesh NV allows the capacitive transient currents idealized only at a single point, so at the common mode equipotential connection point AP Act. By this measure, no circuit over the vehicle ground KL31 more excitable. The vehicle body or the metallic structure of the vehicle thus no longer represents a circuit which can convert the disturbing charge-reversal currents.

Housing, shielding, and / or cooling units of the traction battery BT , the traction power lines BL and the control circuit SE (if provided) are of the braid NV and thus of the above components MG . KK . SB . AROUND . SK . PK electrically isolated and individually or jointly directly via a ground strap to the vehicle mass KL31 electrically connected.

In the 2 illustrated drive device AV is different from the one in 1 shown drive device in that this still a high-voltage filter HF whose parasitic capacitances also coincide with the network of low-impedance compounds NV , esp. Direct, niederimpedantelektrisch are connected. In this case, there is the network of niederimpendanten compounds NV mostly from a heat sink KK , The parasitic capacities PK of the DC link capacitor ZK the drive device AV are directly with the heat sink KK connected in a low-impedance manner.

In the 2 is also illustrated that high-voltage and low-voltage batteries BT . LB , Data connections CAN , such as B. CAN -Bus, the motor vehicle, as well as control circuit SE the drive device AV from the network of low-impedance compounds NV are electrically isolated.

Claims (15)

An electric drive device (AV) for driving a hybrid electric / electric vehicle, comprising: - At least two (power) electrical arrangements (EM, ST, VS, GT, LE) with parasitic capacitance, each having an electromagnetic shielding unit (SK, UM, SB), an electrically conductive cooling unit (KK) and / or an electrically conductive mechanical protection unit (MG) include; - wherein the shielding units (SK, UM, SB), the cooling units (KK) and / or the protection units (MG) via low-impedance connections (NV) are electrically connected to each other and have a common electrical connection point (AP); - A series circuit (RS) of a resistor (R) and a coil (SD), wherein the series circuit (RS) electrically connects the connection point (AP) with vehicle ground (KL31) of the hybrid electric / electric vehicle. Drive device (AV) after Claim 1 , where the low-impedance connections (NV) in a frequency range of up to 10 KHz together have a total ohmic resistance of less than 500 μΩ or between 220 to 500 μΩ. Drive device (AV) after Claim 1 or 2 , wherein the low-impedance connections (NV) in a frequency range of up to 1 GHz together have a total insertion loss of less than 6 dB. Drive device (AV) according to one of the preceding claims, wherein the series circuit (RS) has a total resistance value of less than 100 mΩ, or between 50 to 100 mΩ, or between 80 to 100 mΩ. Drive device (AV) according to one of the preceding claims, wherein the series circuit (RS) has a total inductance value of less than 1000 μH, or less than 900 μH, or less than 800 μH. Drive device (AV) according to one of the preceding claims, wherein the series circuit (RS) comprises a protective conductor choke (SD). Drive device (AV) according to one of the preceding claims, wherein the at least two arrangements comprise an electric motor (EM), a power electronics circuit (LE) for operating the electric motor (EM), a gate driver circuit (GT) for operating the power electronics circuit (LE) and / or electrical connections (ST, VS) between the at least two arrangements (EM, GT, LE). Drive device (AV) according to one of the preceding claims, wherein the shielding units at least one shielding plate for electromagnetic shielding of the power electronics circuit (LE) and / or the gate driver circuit (GT), and / or at least one shield contact (SK) of the electrical connections (ST, VS), and / or at least one sheath (UM) of the electrical connections (ST, VS). Drive device (AV) according to one of the preceding claims, wherein the cooling units comprise at least one electrically conductive heat sink (KK) for cooling the electric motor (EM) and / or the power electronics circuit (LE). Drive device (AV) according to one of the preceding claims, wherein the protection units comprise at least one electrically conductive housing parts (MG) of the electric motor (EM), the power electronics circuit (LE) and / or the gate driver circuit (GT). Drive device (AV) according to one of the preceding claims, wherein the low-impedance connections (NV) comprises at least one metal or metal alloy sheet, in particular copper or a copper alloy, which is connected to all of the shielding units (SK, UM, SB), the cooling units (KK) and / or the protective units (MG) is connected low impedance. Drive device (AV) according to one of the preceding claims, wherein the low-impedance connections (NV) comprises a braid of carbon fibers with a metal embedded in the carbon fiber or a carbon alloy embedded in the metal alloy, esp. Copper or a copper alloy, which with all of the shielding (SK, UM, SB), the cooling units (KK) and / or the protection units (MG) is connected low-impedance. Drive device (AV) according to one of the preceding claims, further comprising an intermediate circuit capacitor (ZK) whose parasitic capacitances are electrically connected directly to the low impedance connection (NV). Drive device (AV) according to one of the preceding claims, further comprising a high-voltage battery (BT) and / or a control circuit (SE) for controlling the power electronics circuit (LE) and / or the gate driver circuit (GT), wherein all of the high-voltage battery (BT) and / or the control circuit (ST) are not electrically contacted with the shielding units (SK, UM, SB), the cooling units (KK), the protection units (MG) and / or the low-impedance connections (NV). Hybrid electric / electric vehicle comprising: a vehicle body as vehicle mass (KL31); - A drive device (AV) according to one of the preceding claims, wherein the drive device (AV) via the series circuit (RS) to the vehicle ground (KL31) is electrically connected.

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