WO2011020650A2 - Circuit assembly for a motor vehicle - Google Patents

Abstract

The invention relates to a circuit assembly for a motor vehicle. The circuit assembly comprises an electric motor. The electric motor comprises a control unit, wherein the control unit is designed to actuate the electric motor, in particular a stator of the electric motor, for rotating the rotor. According to the invention, the circuit assembly comprises a controllable switch with a control connection. The controllable switch is connected, in particular in a separable manner, on the input side to a battery potential of an on-board power supply system of the motor vehicle. The controllable switch is connected on the output side to the electric load, in particular the electric motor, preferably to the control unit of the electric motor. The control unit has a control input for receiving an activation signal for activating the load, in particular in the case of an electric motor for rotating a rotor of the electric motor. The control unit is connected to the control connection of the controllable switch and designed to apply a switch signal to the control connection to activate the load depending on the activation signal.

Description

 description

title

 Circuit arrangement for a motor vehicle prior art

 The invention relates to a circuit arrangement for a motor vehicle. The circuit arrangement has an electrical load, for example an electric motor. The electric motor, in particular an electronically commutated electric motor, has an in particular permanent magnetic rotor. The electric motor has a control unit, wherein the control unit is designed to control the electric motor, in particular a stator of the electric motor, for rotating the rotor.

 In known from the prior art electrical consumers in a motor vehicle, such as electric motors, there is the problem that the e- lectric consumer, comprising a control unit, permanently with a

On-board network of the motor vehicle, and thus connected to a battery potential of the electrical system. In the case of a circuit arrangement of the electrical load at a place unprotected from corrosion in the motor vehicle, for example in the case of a radiator fan as a consumer in the region of an engine compartment of the motor vehicle, which comes in contact with splash water when driving on a wet track, remains during a parked state of the motor vehicle, the electrical consumers continue to be connected to the electrical system. The electrical load is switched on or off by the control unit in response to an activation signal in a salaried state. During the off

Leakage currents can then flow from a connected to the electrical system connection of the consumer to a vehicle mass of the electrical system. This can cause a disadvantageous discharge of the battery. Another disadvantage is the consumer of the electrical system by a series connected to the consumer fuse only separated when the consumed by the consumer during operation operating current is exceeded. Disadvantageously, leakage currents smaller than the operating current can damage the

Cause motor vehicle or cause a discharge of the battery.

 From DE 20 2006 013 422 U1 a control device for driving an actuatable by means of an electric motor adjusting mechanism in a motor vehicle is known. The control device is connected to a relay for switching the electric motor and designed to act on the relay to apply a control voltage.

Disclosure of the invention

 According to the invention, the circuit arrangement of the type mentioned in the introduction has a controllably designed switch, preferably a relay or a semiconductor switch, with a control connection. The controllable switch is on the input side connected to a battery potential of a vehicle electrical system of the motor vehicle, in particular separable connected. On the output side, the controllably designed switch is connected to the electrical load, in particular the electric motor, preferably to the control unit of the electric motor. The

Control unit has a control input for receiving an activation signal for activating the load, in particular in the case of an electric motor for rotating a rotor of the electric motor. The control unit is connected to the control terminal of the controllable switch and designed to act on the control terminal for activating the consumer in response to the activation signal with a switching signal.

 Through this circuit arrangement, the consumer himself, in particular the control unit of the consumer, a switching signal for activating the

Generate consumer. Advantageously, the switching signal consumes little power so that a circuit for generating the switching signal may be provided with a fuse having a smaller melting current as a fuse for securing the operating current of the load.

If the consumer, in particular a connection of the consumer's control unit, is exposed to moisture, for example salty spray water in Bonding comes, and on the salty spray water leakage to the vehicle body and flows through the vehicle body to a ground terminal of the electrical system, so this leakage with a - relative to a fuse to secure the operating current - small fuse, in particular fused fuse. If the leakage current exceeds a separation current of the fuse, in particular a predetermined by the fuse separation current value, the fuse can interrupt the control circuit, thus preventing a discharge of the battery.

 In a preferred embodiment of the circuit arrangement, a controllably designed switch on the output side with the consumer, in particular the electric motor, connecting power line longer than an electrical connection between the consumer, preferably a stator of the electric motor, and the control unit. As a result, the control unit-preferably as a component of the consumer-can be arranged close to the consumer, in particular the electric motor, wherein the controllable switch can advantageously be arranged at a location protected from corrosion in the motor vehicle, for example, far from the consumer ,

 In a preferred embodiment of the circuit arrangement, the control unit is mechanically connected to a housing of the electric motor, preferably to the stator. As a result, the electric motor can advantageously be produced at low cost.

 In an advantageous embodiment, the control input of the control unit is designed for connection to a data bus. As a result, the load, in particular the electric motor, can advantageously be integrated into a data bus system of the motor vehicle. The data bus is preferably a field bus, in particular a LIN bus (LIN = Local Area Network) or a CAN bus (CAN = Controller Area Network), or a PWM signal line (PWM = Pulse Width Modulation).

The invention also relates to a motor vehicle having a circuit arrangement according to the above-described type. In the motor vehicle, the relay is preferably arranged at a location protected from corrosion. More preferred is the

Consumer, for example, the electric motor arranged at a non-corrosion protected place. As a result, the consumer can advantageously be connected to the motor vehicle at low cost. For example, the electric motor and the connections of the electric motor do not need to be particularly complicated encapsulated and so be protected from water spray or condensation.

 The invention also relates to a method for activating an electrical load in a motor vehicle, in particular an electric motor in a motor vehicle, preferably by means of a circuit arrangement of the type described above. In the method, the consumer has a with the

Consumer in particular mechanically connected control unit. In the method, a controllable switch, in particular relay or semiconductor switch, is preferably arranged on a location of the motor vehicle which is better protected against corrosion than the consumer. In the method is in a

Step generates an activation signal to activate the consumer. In a further step of the method, a switching signal for actuating the controllable switch, in particular relay or semiconductor switch is generated in response to the activation signal, and by means of the controllable switch so an operating current for operating the consumer on the

 Consumer switched. The method advantageously allows a leakage current to be limited, which flows from a terminal of the consumer to a ground terminal of a vehicle electrical system.

 In a preferred embodiment of the method, the activation signal is a signal of a data bus or a PWM signal line (PWM = pulse width modulation). The data bus is preferably a field bus, in particular a CAN bus or a LIN bus.

 In an advantageous embodiment of the method, the consumer is an electric motor, in particular an electric motor of a radiator fan or a power steering system of the motor vehicle. Due to the process, the consumer, in particular radiator fan or the power steering, does not need to be protected from splashing water in a particularly complicated manner.

 The invention will now be described below with reference to figures and further embodiments. Further advantageous embodiments of the circuit arrangement result from the features described in the dependent claims, as well as from the features described in the following description of the figures.

Figure 1 shows an embodiment of a circuit arrangement for a motor vehicle with an electrical load, and with a relay, which of the electrical load itself can be activated via a control line;

 FIG. 2 shows an exemplary embodiment of a method for operating a circuit arrangement with an electric motor and with a controllably designed switch.

 Figure 1 shows - schematically - an embodiment of a circuit arrangement 1 for a motor vehicle 3. The circuit arrangement 1 has in this embodiment as an electrical load on an electric motor with a stator 10. In this embodiment, the stator 10 has three stator coils connected in star connection, namely the stator coils 12, 14 and 16.

 Also conceivable is a delta connection of the stator, or a DC motor as an electric motor, for example a series-wound motor. The electric motor also has a rotor 1 1 and a control unit 18. The control unit 18 has a power output stage 20 and a processing unit 22 connected to the power output stage 20. The processing unit 22 is formed for example by a microprocessor, a microcontroller or an FPGA (FPGA = Field Programmable Gate Array). The control unit 18 is designed to energize the stator coils 12, 14 and 16 of the stator 10 by means of the processing unit 22 and the power output stage 20 such that the stator 10 can generate a rotating magnetic field for rotating the rotor 1 1 of the electric motor.

 The rotor 1 1 is connected by means of a motor shaft 15 with a fan 17. The fan 17 is in this embodiment a radiator fan of a radiator 5 of the motor vehicle 3. Also conceivable is a power steering unit connected to the motor shaft 15, a window regulator or another electrical device, which is arranged at a location unprotected from spray water or corrosion.

The circuit arrangement 1 also has a relay 30. The relay 30 has a relay coil 32 and a switch operatively connected to the relay coil 32. The switch of the relay 30 has at least two switching contacts, wherein a first switching contact of the switch is connected to a terminal 38, and a second terminal of the switch is connected to a terminal 39. The terminal 39 is connected via a fuse 46 to a terminal 44 of a vehicle electrical system 40. The terminal 44 is, for example, a positive potential leading terminal of the electrical system, which, for example, according to a DIN standard 72552 is designated as terminal 30. The vehicle electrical system 40 also has a ground connection 42. The relay coil 32 is connected to the ground terminal 42 with a first terminal 34, and connected to a control terminal 24 of the control unit 18 via a connecting line 52 via a connecting line 52, which corresponds to the aforementioned control terminal. The control unit 18 is designed to generate a switching signal as a function of an activation signal received via an input 26 of the control unit 18, and to send this output to the relay 30 via the control output 24 and the connecting line 52. The relay 30, in particular the relay coil 32, can close the switch of the relay 30 as a function of the switching signal received via the connecting line 52. The control unit 18 has a connection 28 for the positive potential. The positive potential terminal 28 is connected to the power output stage 20. The power output stage 20 can thus be supplied via the terminal 28 with an operating current for operating the stator 10 of the electric motor. The connection

28 is connected via a connecting line 54 to the terminal 38 of the switch 30 of the relay. The connecting line 54 corresponds to the aforementioned power line and is designed to conduct an operating current of the load, in this embodiment, an electric motor.

When the switch of the relay 30 is closed by means of the relay coil 32 as a function of the switching signal received via the connecting line 52, an operating current for operating the power output stage 20 flows from the vehicle electrical system 40 via the terminal 44, the fuse 46, the second terminal of the relay 30, the closed switch of the relay 30, the first terminal 38 of the relay 30 and the connecting line 54 to the terminal 28 of the control unit 18. The operating current flows further from the terminal 28 through the power output stage 20, and of the power output stage 20, in particular of switching transistors of the power output stage 20, to a ground terminal of the power output stage 20.

The circuit arrangement also has a control unit 48. The control unit 48 is designed to control the operation of components of the motor vehicle 3, for example, an operation of the engine, in particular the internal combustion engine. The control unit 48 is connected to the control input 26 by means of a connection 50, in particular a data bus 50 or a PWM signal line. The data bus 50 may be, for example, a CAN bus or a LIN bus be. The processing unit 22 has, for example, an interface (not shown in this figure) for connecting to the data bus 50.

 The power output stage 20 is connected via a connecting line 56 to the processing unit 22. The output stage 20 is the output side via a connecting line 57 with the stator coil 16, via a connecting line

58 connected to the stator coil 14 and via a connecting line 59 to the stator coil 12. The connecting lines 57, 58 and 59 are formed in this embodiment, each shorter than the connecting line 54 from the terminal 38 of the relay 30 to the terminal 28 of the control unit 18 of the electric motor. The relay 30 can thereby advantageously in the motor vehicle 3 - in this

Embodiment in the region of an end wall of the motor vehicle 3 - be arranged protected against spray water 60. The spray water 60 may contact the electric motor with the stator 10 and the control unit 18. From the terminal 28 can then, for example, a leakage current 62 - indicated by dashed lines - flow to the ground terminal 42 of the vehicle ground. When the motor vehicle is turned off, and for example the internal combustion engine of the motor vehicle 3 is not in operation, then the terminal 39 can be connected via the fuse 46 to the positive potential of the terminal 44 of the vehicle electrical system 40.

The control unit 48 and the processing unit 22, for example - not shown in this figure - be connected to a terminal of the electrical system 40 via a fuse whose separation current, in particular melt flow is much smaller than the separation current, in particular melt current of the fuse 46. For example, this corresponds Connection of a terminal 15 according to DIN-NORM 72552.

From the terminal 28 can advantageously no leakage current 62 to flow to the ground terminal 42 because of the non-activated relay 30. When the control unit 18 receives an activation signal for activating the fan 17 via the control input 26, the control unit 18 can send the switching signal for activating the relay 30 via the control output 24.

In this way, the control unit 18 switches the operating current for operating the fan 17 itself in response to the activation signal.

FIG. 2 shows an exemplary embodiment of a method for operating an electrical consumer in a motor vehicle, for example by means of the circuit arrangement 1 illustrated in FIG. In the method, the Consumers on a mechanically connected to the consumer control unit. Furthermore, in the method, a controllable switch, in particular relay or semiconductor switch, is arranged at a location of the motor vehicle which is better protected against corrosion than the consumer. In the method, an activation signal for activating the consumer is generated in a step 80. In a further step 82 of the method, a switching signal for actuating the controllable switch is generated in response to an activation signal, and connected in a step 84 by means of the controllable switch such an operating current for operating the consumer to the consumer.

 In a step 86, a leakage current is limited, which flows from a terminal of the consumer to a ground terminal of a vehicle electrical system of the motor vehicle. The leakage current can be limited, for example, by means of a fuse, in particular a fuse, wherein a limit value for the leakage flow is smaller than the operating current for operating the consumer. For example, the activation signal is a signal of a PWM signal line or a data bus, in particular a CAN bus or LIN bus.

 The consumer is, for example, an electric motor of a radiator fan, an electric motor of a window regulator or a power steering. Further exemplary embodiments for the consumer are a consumer arranged in the engine compartment of the motor vehicle, for example an electric injection pump or a drive of an anti-lock braking system, a steering motor, in particular power steering, an on-board network control device, a battery monitoring device, in particular a battery state-of-charge monitoring device Vehicle lighting with at least one incandescent lamp or light-emitting diode, a vehicle headlight, in particular gas discharge headlights, for example with the gas xenon.

Claims

claims  1 . Circuit arrangement (1) for a motor vehicle (3) with an electric motor (10, 18), in particular electronically commutated electric motor (10, 18), wherein the electric motor (10, 18) has a rotor and a control unit which is designed to control the electric motor for rotating the rotor (1 1), characterized in that the circuit arrangement (1) a controllable switch (30), in particular a relay (30) or a semiconductor switch, with a control terminal (36), wherein the controllable switch (30) on the input side (39) with a battery potential (44) of a vehicle electrical system (40) of the motor vehicle (3) is connected and the output side (38) with the electric motor (28, 18, 20) , in particular the control unit (18, 20) is connected, wherein the control unit (18) has a control input (26) for receiving an activation signal for rotating the rotor (1 1), and wherein the control unit (18, 24) with the control terminal ( 36) of the controllable switch (30) is connected and designed to act on the control connection (36) for activating the electric motor (10, 11) as a function of the activation signal with a switching signal.  2. Circuit arrangement (1) according to claim 1, characterized in that a controllably designed switch (30) on the output side (38) to the electric motor (20, 10) connecting power line (54) is longer than an electrical connection (57, 58, 59) between a stator (10) of the electric motor and the Control unit (20, 18).  3. Circuit arrangement (1) according to one of the preceding claims, characterized in that the control unit (18, 20) is mechanically connected to a housing of the electric motor (10, 11). 4. Circuit arrangement (1) according to one of the preceding claims, characterized in that the control input (36) of the control unit (18) is designed for connection to a data bus (50).  5. Circuit arrangement (1) according to claim 4, characterized in that the data bus (50) is a field bus, in particular a local area network bus or a controller area network bus, or a pulse width modulation signal line.  6. Motor vehicle (3) with a circuit arrangement (1) according to one of the preceding claims, characterized in that the controllable switch (30) is arranged on a protected from corrosion location of the motor vehicle (3).  7. A method for activating an electrical load (10, 1 1) in a motor vehicle, in particular an electric motor (10), in particular by means of a circuit arrangement (1) according to one of the preceding claims, wherein the consumer (10) has a control unit (18). and is in particular mechanically connected to the control unit (18), and in which a controllable switch (30), in particular relay (30) or semiconductor switch, is arranged at a location of the motor vehicle better protected from corrosion than the consumer (10), and wherein in the method in a step (80) Activation signal for activating the consumer (10) is generated, and in a further step (82) in response to the activation signal, a switching signal for actuating the controllable switch (30) is generated, and by means of the controllable switch (30) an operating current to Betrei - Ben of the consumer (10) to the consumer (10) is switched (84).  8. The method according to claim 7, characterized in that the activation signal is a signal of a data bus (50).  9. The method according to claim 7 or 8, characterized in that the data bus (50) is a CAN bus or a LIN bus. 10. The method according to any one of claims 7 to 9, characterized in that the consumer is an electric motor (10) of a radiator fan (17) or a power steering.