Controller, drive dynamic system, and motor vehicle

Abstract

The invention relates to a controller (2) for electrically operating at least one electric / electronic device (3), in particular a solenoid valve (4), comprising a supply connection (13) which is connected or can be connected to an onboard electrical system, a device connection (15) which is connected or can be connected to the device (3), an actuatable switch device (5) which is connected to the supply connection (13) and to the device connection (15), and a control unit (6) which is designed to actuate the switch device (5) so as to electrically connect or disconnect the supply connection (13) and the device connection (15). According to the invention, a step-down converter (8) with an actuatable semiconductor switch (16) is interposed between the supply connection (13) and the device connection (15), and the semiconductor switch (16) forms the switch device (5).

Description

[0001] Description

[0002] title

[0003] Control device, driving dynamics system and motor vehicle

[0004] The present invention relates to a control device for electrically operating at least one electrical / electronic device, in particular an electromagnetic valve, having a supply connection that is connectable or connected to an on-board power supply of a motor vehicle, having a device connection that is connectable or connected to the device, having a controllable switching device that is connected to the supply connection on the one hand and to the device connection on the other hand, and having a control unit that is designed to control the switching device to establish or break an electrical connection between the supply connection and the device connection.

[0005] Furthermore, the invention relates to a driving dynamics system for a motor vehicle, comprising at least one electrical / electronic device and a control device which is designed as described above.

[0006] Furthermore, the invention relates to a motor vehicle with an on-board electrical system, in particular a 48V on-board electrical system, and with such a driving dynamics system.

[0007] State of the art

[0008] Control devices of the type mentioned above are known from the prior art. For example, it is common practice in so-called ESP systems (ESP = Electronic Stability Program) to provide one or more electrically controllable valves, in particular solenoid valves, which are integrated into a hydraulic brake circuit and, when controlled, connect a hydraulic wheel brake to a pressure supplier or a pressure sink for each wheel, for example. In conventional motor vehicles with combustion engines, the solenoid valves are integrated into the vehicle's electrical system, which operates with a mains voltage of 12 volts. Modern motor vehicles with an electric motor as the sole or additional drive unit generally have an electrical system with a comparatively higher voltage, for example 48 volts, due to the increased electrical requirements.Since these vehicles are currently still equipped with conventional driving dynamics systems, especially hydraulic braking systems, it makes sense to design the electrical / electronic devices of a driving dynamics system for the higher operating voltage. However, this is not absolutely necessary for their functionality, so this adaptation alone would offer the advantage of direct integration into the existing vehicle electrical system.

[0009] Disclosure of the invention

[0010] The present invention, with the features of claim 1, has the advantage that the electronic / electrical devices of a driving dynamics system previously used in conventional motor vehicles can also be used in modern motor vehicles with a different on-board power supply voltage, without the need for complex, cost-intensive, and space-consuming technology. While in conventional vehicles with combustion engines, a driving dynamics system and its electrical / electronic devices are generally operated in a 12V on-board power supply, the integration of these devices into an on-board power supply with a high operating voltage of, in particular, 24V or 48V is now possible, without the need for complex pre-wiring.To this end, the invention provides that a step-down converter with a controllable semiconductor switch is interposed between the supply connection and the device connection, and that the semiconductor switch forms the switching device. The step-down converter reduces the electrical voltage of the available on-board electrical system to the operating voltage for which the electrical / electronic device is designed. In particular, the step-down converter reduces the on-board electrical system voltage from 48 volts to 12 volts. This makes it possible to operate the electrical / electronic device, which has an operating voltage of 12 volts, even on an on-board electrical system with an on-board electrical system voltage of, for example, 48 volts. Because the step-down converter has a controllable semiconductor switch, the operating voltage of the on-board electrical system is specifically reduced and adjusted to the operating voltage of the electrical / electronic device.Because the device can also be de-energized by controlling the semiconductor switch, the semiconductor switch in accordance with the invention forms the switching device, so that the semiconductor switch performs two functions simultaneously. Firstly, the semiconductor switch reduces the operating voltage to the desired level, and secondly, the semiconductor switch controls the operation of the device, in particular in the manner of a valve relay, by means of which the device or several devices of the driving dynamics system can be de-energized or energized. If the device is designed, for example, as an electromagnetic valve (solenoid valve), as is generally used in today's ESP systems, the semiconductor switch is only switched on when the valve is to be actuated, whereby the semiconductor switch is then actuated in such a way that the valve is operated at its desired or intended operating voltage.As a result, at least one additional switch is eliminated compared to a simple series connection of a step-down converter and switching device. This reduces manufacturing and parts costs, as well as saving installation space. The inventive design of the control device eliminates the need to redesign and manufacture the electrical / electronic device for use with a higher operating voltage. Rather, existing devices designed for a low vehicle electrical system voltage of, for example, 12 volts can continue to be used advantageously. This results in significant cost advantages, and technology that has already proven itself over a long period of time can continue to be used.

[0011] According to a preferred development of the invention, the step-down converter has at least one half-bridge with a high-side switch on the one hand and a low-side switch or a diode on the other, wherein the high-side switch forms the switching device. The switching device is thus coupled or can be coupled to the positive operating voltage of the vehicle electrical system. The half-bridge can have one or two semiconductor switches, wherein in both cases the high-side switch forms the switching device as a semiconductor switch. By eliminating the need for a semiconductor switch as a low-side switch, which is then replaced, for example, by the aforementioned diode, costs can be further reduced.

[0012] The high-side switch is particularly preferably designed as a MOSFET. MOSFET switches are generally known and produce a mass product that can be used cost-effectively. In addition, MOSFET switches are already used in controllable step-down converters for voltage reduction. Because the MOSFET also forms the switching device in the present case, the driving dynamics system can be operated advantageously.

[0013] Furthermore, it is preferably provided that the low-side switch of the half-bridge is designed as a transistor, in particular as a MOSFET. In this case, the half-bridge is formed by two semiconductor switches, with both switching elements preferably being designed as transistors, in particular as MOSFET switches.

[0014] Furthermore, it is preferably provided that the control unit is designed to control the high-side switch using a pulse-width modulation method. Pulse-width modulation allows the desired operating voltage for the device to be optimally adjusted.

[0015] Particularly preferably, the control unit comprises at least one microcontroller. Furthermore, the control unit preferably comprises at least one non-volatile data memory in which control parameters and at least one operating method for controlling the switching device to reduce the operating voltage are stored.

[0016] The driving dynamics system according to the invention with the features of claim 7 is characterized by the inventive design of the control device. This results in the advantages already mentioned above. Preferably, the driving dynamics system is designed as an ESP braking system, with the at least one electrical / electronic device being designed as a controllable hydraulic valve, in particular as a solenoid valve.

[0017] The motor vehicle according to the invention with the features of claim 9 is characterized by the driving dynamics system according to the invention. This results in the advantages already mentioned above.

[0018] Particularly preferably, the power supply is part of the vehicle's electrical system, which is in particular a 48V electrical system. The electrical / electronic device is designed in particular for an operating voltage of 12 volts. The step-down converter is accordingly configured to regulate the operating voltage of the vehicle's electrical system, in particular 48 volts, to the reduced operating voltage of the device, in particular 12 volts.

[0019] Further advantages and preferred features and combinations of features emerge in particular from the above description and from the claims. The invention will be explained in more detail below with reference to the drawings.

[0020] Figure 1 shows an advantageous control device of a driving dynamics system and

[0021] Figure 2 shows the control device in a more detailed representation.

[0022] Figure 1 shows a simplified representation of a driving dynamics system 1 for a motor vehicle with an advantageous control device 2. The driving dynamics system 1 has several controllable electrical / electronic devices 3, in this case in the form of solenoid valves 4. The solenoid valves 4 serve to realize a desired hydraulic pressure in the hydraulic brake circuit of a braking system of the motor vehicle, so that, for example, spinning or locking of individual wheels of the motor vehicle is automatically prevented.

[0023] The control device 2 is usually designed to control a switching device 5 connected upstream of the valves 4 for operating the valves 4. The switching device 5 is in particular a valve relay, by means of which one or more electromagnetic valves or other devices of the driving dynamics system 1 can be switched to be de-energized or energized. For this purpose, the control device 2 has, in addition to the switching device 5, a control unit 6 which controls the switching device 5 depending on the requirements of the braking system or the driving dynamics system 1. In order to individually energize the electromagnetic valves, individually controllable switches 7 are optionally connected upstream of them, which are connected downstream of the switching device 5. Alternatively, the switching device 5 is only connected to a controllable electrical / electronic device 3 oronly one electric solenoid valve 4 is assigned, in which case an individual additional switch 7 is dispensed with and the device 3 is instead connected directly to the device connection of the control device 2.

[0024] According to the present embodiment, the switching device 5 is formed by a step-down converter 8. The step-down converter 8 is embodied as a so-called buck converter, which has a controllable switching element 9, a coil 10, and a capacitor 11, and is generally known from the prior art. A diode 12 is also connected in parallel with the capacitor 11.

[0025] The control device 2 has a supply connection 13, through which the control device 1 can be electrically connected to a vehicle electrical system, in particular a 48V vehicle electrical system. An optional flyback converter diode 14 is connected downstream of the supply connection 13.

[0026] Furthermore, the control device 2 has a device connection 15, through which the control device 2 is or can be connected to the device(s) 3. The control device 2 has the device connection 15 on the output side and is connected to the step-down converter 8 on the input side, so that the step-down converter 8 is interposed between the supply connection 13, optionally the diode 14, and the device connection 15. According to the present exemplary embodiment, the switching element 9 is designed as a semiconductor switch 16, in particular as a MOSFET switch. The semiconductor switch 16 not only forms the switching element 9 of the step-down converter 8, but also the switching device 5, which is connected upstream of the devices 3 or the solenoid valves 4. The step-down converter 9 and the devices 3 are connected directly to one another without any further switches, apart from the optional switches 7, so that in particular the so-called valve relay is omitted.

[0027] The step-down converter 8 reduces the supply voltage of the on-board electrical system from, in particular, 48 volts to the required operating voltage of the devices 3, for example, in the range of 10 to 16 volts. This allows existing devices 3, such as those used in driving dynamics systems in conventional motor vehicles with combustion engines, to be used. Because the step-down converter 8 is designed as a buck converter, the semiconductor switch 16, which is required anyway for the step-down converter, takes over the function of the valve relay present in the ESP system. This saves space and costs. Due to the wide supply voltage range of the ESP system from 10 to 16 volts and the widely varying inductances of the choke 10 of the step-down converter 8, voltage regulation of the output voltage of the step-down converter 8 is not necessary.This results in a purely controlled control of the step-down converter 8 according to the simplified form.

[0028] Ua=Ue*dc(Ue). The required duty cycle dc(Ue) is provided by the control unit 6 using a microcontroller and a look-up table. The control unit 6 activates the step-down converter 8 only when one or more of the solenoid valves 4 are to be activated or operated. This saves energy, and the step-down converter 8 is preferably thermally designed for short-term operation due to the expected relatively short control time of the valves 4, which in turn saves further space and costs. This advantageous design eliminates the need for a complex and expensive switching regulator IC. Figure 2 shows a more detailed illustration of the control device 2. The step-down converter 8 preferably has a half-bridge 17 with the semiconductor switch 16 as the high-side switch 18 and with a transistor 19 as the low-side switch 20.Transistor 19, like semiconductor switch 16, is preferably designed as a MOSFET. Alternatively to a MOSFET or transistor, the low-side switch is designed as a diode. Half-bridge 17 is connected to supply terminal 13 via the high-side switch. The half-bridge 17 is connected, in particular, to ground via the low-side switch.

[0029] The control unit 6 controls the semiconductor switches 16,19 of the half bridge 17.

[0030] The central output of the half-bridge 17 leads to the choke 10 of the step-down converter and in series therewith to the one or more devices 3. Preferably, the control unit 6 is supplied with electrical energy from the 48V vehicle electrical system by a further step-down converter 21, in particular a buck converter.

[0031] The use of a commercially available half-bridge 17 leads to further cost savings. The fact that the step-down converter 8 is only active when the device(s) 3 are controlled also offers an advantage for the EMC behavior and the electromagnetic compatibility of the control device 2 as a whole. Preferably, the control unit 6 is designed to control the switching element 9 or the semiconductor switch 16 in a pulse-width modulated manner, thus ensuring flexible adjustment of the switching frequency and the dead times. Uncontrolled operation is possible by using different time constants of the step-down converter 8 compared to the devices 3. For example, the solenoid valves 4 operate with a time constant of 1 to 5 mH, and the choke 10 of the step-down converter 8 with a time constant of 5 to 10 pH.

Claims

Claims 1 . Control device (2) for electrically operating at least one electrical / electronic device (3), in particular a solenoid valve (4), with a supply connection (13) that can be connected or is connected to an on-board electrical system, with a device connection (15) that can be connected or is connected to the device (3), with a controllable switching device (5) that is connected to the supply connection (13) on the one hand and to the device connection (15) on the other hand, with a control unit (6) that is designed to control the switching device (5) to establish or break an electrical connection between the supply connection (13) and the device connection (15), characterized in that a step-down converter (8) with a controllable semiconductor switch (16) is interposed between the supply connection (13) and the device connection (15), and in that the semiconductor switch (16) forms the switching device (5).

2. Control device according to claim 1, characterized in that the step-down converter (8) has at least one half-bridge (17) with a high-side switch (19) on the one hand and with a low-side switch (20) or a diode on the other hand, wherein the high-side switch (19) forms the switching device (5).

3. Control device according to one of the preceding claims, characterized in that the high-side switch (19) is designed as a MOSFET.

4. Control device according to one of the preceding claims, characterized in that the low-side switch (20) is designed as a transistor, in particular as a MOSFET.

5. Control device according to one of the preceding claims, characterized in that the control unit (6) is designed to control the high-side switch (19) by a pulse width modulation method.

6. Control device according to one of the preceding claims, characterized in that the control unit (6) has at least one microcontroller.

7. Driving dynamics system (1) for a motor vehicle, with at least one electrical / electronic device (3) and with at least one control device (2) which is connected to the device (3) for its operation, characterized by the design of the control device (2) according to one of claims 1 to 6.

8. Driving dynamics system (1) according to claim 7, characterized by the design as an ESP braking system, wherein the at least one device (3) is designed as a controllable electromagnetic valve (4).

9. Motor vehicle with an on-board electrical system, in particular a 48V on-board electrical system, and with a driving dynamics system (1) according to one of claims 7 or 8.

10. Motor vehicle according to claim 9, characterized in that at least one electrical / electronic device (3) of the driving dynamics system (1) is designed for a 12V vehicle electrical system.

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