ELECTRIC MOTOR CONTROL DEVICE

Abstract

The invention relates to a control device (PD) for an electric motor comprising: a housing (100), and a voltage converter for controlling said electric motor, said voltage converter comprising an electronic control board (200) and a power bridge (300), said electronic control board (200) comprising: an electrical power connector comprising a first terminal and a second power supply terminal intended to be electrically connected respectively to the positive and negative terminals of a battery delivering a first voltage, a first electronic circuit having a first ground and intended to be powered by said first voltage, said first electronic circuit comprising a transient voltage suppression diode connected directly between the second power supply terminal and the first ground, said first ground being electrically connected to said housing,a second electronic circuit having a second ground and intended to be powered by a second voltage, different from said first voltage, and an isolation barrier separating the first electronic circuit from the second electronic circuit, said power bridge being intended to be powered by said second voltage. Figure for the abbreviation: Fig. 1,

Description

Title of the invention: CONTROL DEVICE FOR AN ELECTRIC MOTOR Technical field of the invention

[0001] The present invention relates to a control device for an electric motor.

[0002] The present invention also relates to a propulsion system comprising this piloting device and a mobility device comprising this propulsion system or this piloting device.

[0003] A mobility device is, for example, a motorized land vehicle, a train, an aircraft, or a drone. A motorized land vehicle is, for example, a car, a motorcycle, a motorized bicycle, or a motorized wheelchair.

[0004] The present invention can be applied in particular in the field of hybrid or electric motor vehicles. Technological background

[0005] The prior art of propulsion systems for mobility vehicles comprising control devices for electric motors connected simultaneously to a low voltage battery and a high voltage battery is known.

[0006] By "low voltage" is meant a voltage less than 80V, preferably less than or equal to 60V. Correspondingly, by "high voltage" is meant a voltage greater than 80V, preferably greater than or equal to 100V.

[0007] Typically, the electric motor is powered by the high-voltage battery while part of the control electronics of this motor and / or various and sundry sensors are powered by low voltage.

[0008] In this case, it is known to provide isolation between the high voltage component and the low voltage component of the propulsion system to protect a user of the mobility device against the risks of electrocution.

[0009] Achieving robust insulation involves mechanical constraints (for example, the need for a large isolation distance between the high voltage component and the low voltage component) making the design of the electronic board(s) of the control devices difficult (for example, routing problems, component dimensions, etc.) and leading to large control systems.

[0010] Robust insulation is therefore difficult and expensive to achieve.

[0011] Furthermore, even with robust insulation, loss of insulation between the high-voltage component and the low-voltage component, linked for example to the failure of a electronic component may occur and, in this case, the risks of electrocution of the user reappear.

[0012] It may therefore be desirable to provide a propulsion system which makes it possible to overcome at least some of the aforementioned problems. Summary of the invention

[0013] According to a first aspect of the invention, a control device for an electric motor is therefore proposed, comprising: - a case, and - a voltage converter intended to drive said electric motor, said voltage converter comprising an electronic control board, said electronic control board being placed inside said housing and a power bridge comprising several switching arms each having in series upper and lower semiconductor switches, said electronic control board comprising: - a power supply connector comprising a first terminal and a second power supply terminal intended to be electrically connected respectively to the positive and negative terminals of a battery delivering a first voltage, - a first electronic circuit having a first ground and intended to be powered by said first voltage, said first electronic circuit comprising a transient voltage suppression diode connected directly between the second power supply terminal and the first ground, said first ground being electrically connected to said housing, - a second electronic circuit having a second ground and intended to be powered by a second voltage, different from said first voltage, and - an isolation barrier separating the first electronic circuit from the second electronic circuit, said power bridge being intended to be powered by said second voltage.

[0014] Thanks to the invention, the component powered by the second voltage and the component powered by the first voltage of the control device are integrated into a housing which limits the risks of electrocution when the housing is closed and connected to the chassis of the vehicle.

[0015] Furthermore, and advantageously, the presence of a transient voltage suppression diode, also known as a TVS diode (from the English "transient-voltage-suppression"), between the control device housing and the second power supply terminal intended to be connected to the negative terminal of the low-voltage battery limits the voltages accessible at the level of the electronic board's power connector, even in the event of loss of insulation, thus preventing the risk of electrocution at this connector.

[0016] Thus, a TVS transient voltage suppression diode makes it possible to rapidly limit the voltage difference between the power supply connector of the electronic board and the housing (connected to the chassis of the mobility device when the control unit is integrated into it). For example, for a second voltage of 900V and a first voltage of 12V, a properly sized TVS transient voltage suppression diode makes it possible to limit, in 0.5 ms, the voltage at the power supply connector of the electronic board to less than 60V.

[0017] Advantageously, the presence of the TVS transient voltage suppression diode also reduces the constraints on the robustness of the isolation barrier, which in turn reduces the size and cost of the control device.

[0018] The invention may further include one or more of the following optional features, according to any technically possible combination.

[0019] Optionally, the control device for an electric motor may also include: - a first and a second electrical connection, - a wall electrically connected to said first mass, - said wall at least partially surrounding said first and said second electrical connection, and - a second power supply connector accessible from outside said housing, said second power supply connector comprising a first terminal and a second power supply terminal intended to be electrically connected respectively to the positive and negative poles of said battery delivering said first voltage, said first terminal and said second power supply terminal of said second power connector being connected respectively to said first terminal and said second power supply terminal of said power connector of said electronic control board by said first electrical connection and said second electrical connection respectively.

[0020] Optionally, the electronic control board also includes a flat portion on which the power supply connector of the electronic control board is positioned, said wall being in the form of a right cylinder having a base parallel to said flat portion, said base including an opening through which said first and said second electrical connections pass, said opening being opposite said power supply connector of said electronic control board.

[0021] Optionally also, the first electronic circuit further includes a resistor electrically connected between the second power supply terminal and the first ground.

[0022] Optionally also, the first voltage is a voltage less than 80V and said second voltage is a voltage greater than or equal to 80V.

[0023] Optionally also, the first electronic circuit includes a common mode filter comprising a first and a second input connected respectively to the first and second power supply terminals.

[0024] Optionally also, the first and second inputs of the common mode filter are connected directly, i.e. without the intermediary of another passive or active component, respectively to the first and second power supply terminals.

[0025] According to a second aspect of the invention, a propulsion system is also proposed comprising a piloting device according to the first aspect of the invention and an electric motor controlled by this piloting device.

[0026] Optionally, the propulsion system includes, in addition to a first battery delivering the first voltage and connected to the first terminal and the second power supply terminal of the second power supply connector, a second battery delivering the second voltage to the second electronic circuit.

[0027] According to a third aspect of the invention, a mobility device is also proposed comprising a control device for an electric motor according to the first aspect of the invention or a propulsion system according to the second aspect of the invention. Brief description of the figures

[0028] The invention will be better understood with the aid of the following description, given solely by way of example and made with reference to the accompanying drawings in which: - Figure [1] is an exploded view of a control device according to one embodiment of the invention, - [Fig.2] is a schematic representation of the electronic control board of the control device of [Fig.1], - [Fig. 3] is a schematic representation of the power bridge of the control device of [Fig. 1], and - [Fig.4] represents two enlargements of the relative arrangement of the electronic control board, the support and the housing of the control device of [Fig.1]. Detailed description of the invention

[0029] With reference to [Fig. 1], an embodiment of a DP control device for a system according to the invention will now be described. This system is, for example, intended to be installed in a mobility device such as a motor vehicle.

[0030] The system according to the invention comprises an electric motor ME, the control device DP controlling this electric motor ME, a low voltage battery BATL and a high voltage battery BATH.

[0031] The low voltage battery BATL delivers a first voltage, for example 12V, while the high voltage battery BATH delivers a second voltage V2, different from the first voltage, for example 900V.

[0032] The DP control device comprises - a 100 case, - a voltage converter intended to drive the ME electric motor, and - a 400 support electrically connected to said 100 box.

[0033] The voltage converter includes an electronic control board 200 placed inside the housing 100 and a power bridge 300.

[0034] The support 400 allows, for example, filter elements or auxiliary components inserted in the housing 100 to be held.

[0035] We will now describe, in relation to the schematic representation in [Fig. 2], the electronic control board 200. This comprises: - a 210 power supply connector comprising a first terminal BIN1 and a second power supply terminal BIN2 electrically connected respectively to the positive and negative poles of the low voltage battery BATL such that the first voltage is present between the first terminal BIN1 and the second power supply terminal BIN2, - a first electronic circuit LV having a first ground GND1 and powered by the first voltage via the power supply connector 210, this first electronic circuit LV including a transient voltage suppression diode TVS connected directly between the second power supply terminal BIN2 and the first ground GND1, this first ground being itself electrically connected to the housing 100, for example, via a screw screwed onto a shaft belonging to the housing 100, - a second HV electronic circuit having a second ground GND2 and intended to be powered by the second voltage V2 delivered by the high-voltage battery BATH, and - an ISOL isolation barrier physically and electrically separating the first electronic circuit LV from the second electronic circuit HV. In the example described here, this ISOL isolation barrier is implemented by a physical separation, i.e. an opening of sufficient width to allow compliance with the minimum distances necessary for insulation in the air and along the surfaces, in the support of the electronic control board 200.

[0036] Thus, advantageously, the presence of the TVS transient voltage suppression diode limits the voltages accessible at the power supply connector of the electronic board, even in the event of loss of insulation and thus prevents the risks of electrocution at the level of this connector.

[0037] Moreover, thanks to this TVS transient voltage suppression diode, the implementation of the ISOL isolation barrier is very simple, which makes it possible to reduce the size of the DP control device and its cost.

[0038] The first electronic circuit LV optionally includes a common-mode filter (FMC) comprising a first and a second input connected respectively to the first and second power supply terminals of the power supply connector 210. Furthermore, in this configuration, the FMC common-mode filter is the only component of the first electronic circuit LV connected to the first power supply terminal BIN1. In addition, the first and second inputs of the FMC common-mode filter are connected directly to the first and second power supply terminals BIN1 and BIN2, respectively, of the power supply connector 210. The implementation of a common-mode filter is known to those skilled in the art and will therefore not be described here.

[0039] Optionally, the first electronic circuit LV also includes an impedance Z electrically connected between the second power supply terminal BIN2 and the first ground GND1. The impedance Z is, for example, represented by an electrically connected braid. The braid extends, in particular, partially outside the housing 100.

[0040] In the example of [Fig.3], the electric motor ME is a three-phase electric machine, i.e. comprising three stator phases U, V, W, of which, in the example described, the first respective ends are connected to a neutral point N. The three stator phases U, V, W are driven respectively by a phase voltage Pu, Pv, Pw supplied by the power bridge 300 controlled by a control system SC.

[0041] The power bridge 300 is connected, on the one hand, to the terminals BH+, BH- of the high voltage battery BATH and, on the other hand, to the electric motor ME to supply the stator phases U, V, W from the second voltage V2 supplied by the high voltage battery BATH.

[0042] In the example described here, the 300 power bridge comprises three power modules supplied by the BATH high-voltage battery. Each power module comprises a switching arm respectively associated with the stator phases U, V, W. Each arm has a high-side semiconductor switch Q1, Q3, Q5, also called the high-side switch, connected to the BH+ terminal, and a low-side semiconductor switch Q2, Q4, Q6, also called the low-side switch, connected to the BH- terminal. The high-side and low-side semiconductor switches are further connected to each other at a midpoint Pu, Pv, Pw, which is connected to the associated stator phase U, V, W.

[0043] Each arm is intended to be controlled by the SC control system to switch between two configurations. Thus, in the first, called the high configuration, the high-side switch is closed and the low-side switch is open so that the input voltage V2 is applied to a second end of the associated stator phase U, V, W. In the second, called the low configuration, the high-side switch is open and the low-side switch is closed so that a zero voltage is applied to the second end of the associated stator phase U, V, W. The power bridge 300 is controlled to switch each arm between these two configurations, so as to regulate the voltages Pu, Pv, Pw and the currents flowing through the stator phases U, V, W.

[0044] Each switch Q1, Q2, Q3, Q4, Q5, Q6 in the described example comprises an insulated-gate field-effect transistor (also known by the acronym MOSFET, for Metal Oxide Semiconductor Field Effect Transistor). Alternatively, each switch is an insulated-gate bipolar transistor (also known by the acronym IGBT, for Insulated Gate Bipolar Transistor).

[0045] The SC control system is designed to transmit open or close commands C_Q1, C_Q2, C_Q3, C_Q4, C_Q5, C_Q6 to each of the switches Q1, Q2, Q3, Q4, Q5, Q6. This SC control system is implemented at least in part by the first electronic circuit LV and by the second electronic circuit HV of the control electronic board 200. In other words, one part of the SC control system is isolated from another part of the SC control system by the isolation barrier ISOL.

[0046] In addition, a capacitor C is connected between the terminals BH+, BH-. The capacitor C comprises, for example, one or more capacitors, for example, electrolytic capacitors.

[0047] We will now describe in relation to [Fig.4], the relative arrangement of the power supply connector 210 of the electronic control board 200 with respect to the support 400 and the housing 100. On [Fig.4], the arrangement on the right is distinguished from the arrangement on the left by the absence of the housing 100.

[0048] The housing 100 includes, firstly, a second power supply connector 500 accessible from outside the housing 100. This second power supply connector 500 comprises a first terminal and a second The power supply terminals are electrically connected to the positive and negative terminals of the low-voltage battery BATL, respectively. The first and second power supply terminals of the second electrical connector 500 are connected to the first terminal BIN1 and the second power supply terminal BIN2 of the electrical connector 210 of the electronic board 200, respectively, by a first and second electrical connection (not shown in the figure). The first and second electrical connections are, for example, electrical conductors, optionally surrounded by an insulating sheath except at their ends.

[0049] Furthermore, the electronic control board 200 includes a flat portion S on which the power supply connector 210 of this electronic control board 200 is positioned.

[0050] Furthermore, the support 400 includes a wall P extending from its base. In the example described here, this wall has the shape of a right cylinder with an opening O at its base. It should be noted that the base of a right cylinder is not necessarily circular or oval. Thus, in the example described here, the base of the right cylinder has a shape close to a half-rectangle with rounded corners. Moreover, the base of the right cylinder of the wall P is parallel to the flat portion S of the electronic control board 200, and the opening O is opposite the first electronic circuit LV of the electronic control board 200, more precisely opposite the power supply connector 210, when the electronic control board 200 and the support 400 are positioned in the housing 100.Optionally, as in the example described here, the support 400 can be attached to the electronic control board 200 so as to ensure the placement of the opening 0 opposite the power supply connector 210.

[0051] It will be noted that when the support 400 is positioned in the housing 100, the wall P and the inner side face of the housing 100 on the outside of which the second power supply connector 500 is positioned form a wall P'.

[0052] Thus, to connect the second power supply connector 500 fixed on the outside of the housing 100 and the electrical connector 210 of said electronic board 200, the first electrical connection and the second electrical connection are positioned inside the housing 100 and are surrounded by the wall P' so that these electrical connections are isolated not only from the high voltage circuit HV of the electronic control board 200 but also from all high voltage components of the DP control device.

[0053] Thus, advantageously, the presence of the transient voltage suppression diode TVS and the walls P, P' limit the voltages accessible at the second power supply connector 500 even in the event of insulation loss and thus prevents the risk of electrocution at the level of this second 500 power supply connector.

[0054] It should also be noted that the invention is not limited to the embodiments described above. It will indeed be apparent to those skilled in the art that various modifications can be made to the embodiments described above, in light of the information just disclosed to them.

[0055] For example, the electrical machine may be an electrical machine comprising two three-phase systems, each with three phases. The two three-phase systems are intended to be electrically phase-shifted by 120° relative to each other. In this case, the power bridge comprises two sets of three switching arms, each with upper and lower semiconductor switches in series.

[0056] In the detailed presentation of the invention given above, the terms used shall not be interpreted as limiting the invention to the embodiments set forth in this description, but shall be interpreted as including all equivalents which can be foreseen by a person skilled in the art by applying their general knowledge to the implementation of the teaching which has just been disclosed to them.

Claims

2. Demands

1. Control device (CD) for an electric motor comprising: - a case (100), and - a voltage converter intended to control said electric motor, said voltage converter comprising an electronic control board (200), said electronic control board being placed inside said housing and a power bridge (300) comprising several switching arms each having in series upper and lower semiconductor switches, said electronic control board (200) comprising: - a power supply connector (210) comprising a first terminal (BIN1) and a second power supply terminal (BIN2) intended to be electrically connected respectively to the positive and negative terminals of a battery delivering a first voltage, - a first electronic circuit (LV) having a first ground (GND1) and intended to be powered by said first voltage, said first electronic circuit (LV) comprising a transient voltage suppression diode (TVS) connected directly between the second supply terminal (BIN2) and the first ground (GND1), said first ground (GND1) being electrically connected to said housing (100), - a second electronic circuit (HV) having a second ground (GND2) and intended to be powered by a second voltage (V2), different from said first voltage, and - an isolation barrier (ISOL) separating the first electronic circuit (LV) from the second electronic circuit (HV), said power bridge being intended to be powered by said second voltage (V2). Control device (CD) of an electric motor according to the preceding claim, further comprising: - a first and a second electrical connection, - a wall (P, P') electrically connected to said first ground (GND1), - said wall (P, P') at least partially surrounding said first and said second electrical connection, and - a second electrical power connector (500) accessible from outside said housing (100), said second electrical power connector (500) comprising a first terminal and a second power terminal intended to be electrically connected respectively to the positive and negative poles of said battery delivering said first voltage,said first terminal and said second power supply terminal of said second electrical connector being connected respectively to said first terminal (BIN1) and said second power supply terminal (BIN2) of said electrical connector (210) of said electronic control board (200) by said first electrical connection and said second electrical connection respectively.

3. Control device (DP) of an electric motor according to the preceding claim in which said electronic control board (200) comprises a flat portion (S) on which is positioned said power supply connector (210) of said electronic control board (200), said wall (P, P') being in the form of a right cylinder having a base parallel to said flat portion, said base comprising an opening (O) through which passes said first and said second electrical connection, said opening (O) being opposite said power supply connector (210) of said electronic control board (200).

4. Control device (DP) of an electric motor according to any one of the preceding claims in which said first electronic circuit (LV) further comprises a resistor (R) electrically connected between the second supply terminal (BIN2) and the first ground (GND1).

5. A control device (CD) for an electric motor according to any one of the preceding claims, wherein said the first voltage is a voltage less than 80V and the said second voltage (V2) is a voltage greater than or equal to 80V.

6. Propulsion system comprising a piloting device (PD) according to any one of claims 1 to 5 and an electric motor controlled by said piloting device.

7. Propulsion system according to the preceding claim further comprising a first battery delivering said first voltage and connected to said first terminal and to said second power supply terminal of said second power supply connector and a second battery delivering said second voltage to said second electronic circuit.

8. Mobility device, for example a vehicle, comprising a control device for an electric motor according to any one of claims 1 to 5 or a propulsion system according to any one of claims 6 to 7.

Images