Control unit, actuator arrangement, and thermal management arrangement of a motor vehicle

Abstract

Control unit (1) for controlling a plurality of stepper motors (2), the control unit (1) comprising: a driver (4), a microcontroller (3) which controls the driver (4) to power the stepper motors (2), and a plurality of switches (5), one of which is arranged between the driver (4) and a respective one of the stepper motors (2), wherein a respective switch (5) connects or disconnects the stepper motor (2) assigned to it with the driver (4), characterized in that at least one of the switches (5) has at least one reversing circuit (6) by means of which at least one phase of one of the stepper motors (2) can be reversed, so that this stepper motor (2) rotates in a first direction of rotation in a first switching state of the reversing circuit (6) and in a second direction of rotation in a second switching state of the reversing circuit (6).

Description

[0001] The present invention relates to a control unit for controlling a plurality of stepper motors, comprising a microcontroller that controls a driver for supplying current to the stepper motors. The invention further relates to an actuator assembly and a thermal management assembly of a motor vehicle.

[0002] Electric motors are increasingly being used to power motor vehicles, creating alternatives to combustion engines that require fossil fuels. Considerable efforts have already been made to improve the everyday suitability of electric drives and also to provide users with the same level of driving comfort they are accustomed to.

[0003] In the development of such electrical machines, there is a continuing need to increase their power density, making the necessary cooling increasingly important. Due to the necessary cooling performance, hydraulic fluids, such as cooling oils, have become the preferred choice in most designs for dissipating heat from the thermally stressed areas of an electrical machine and / or transmission and / or power electronics.

[0004] Such cooling systems typically have various media circuits, some of which are thermally coupled, such as heating or cooling circuits. These media circuits and their operation are often summarized under the term thermal management. Within these thermal management systems, there is a strong need to control them via controllable actuators, such as valves, which requires a considerable amount of corresponding control electronics and cabling.

[0005] Stepper motors are a well-known way of operating an actuator, such as a valve. Stepper motors are usually configured as synchronous motors, in which the rotor of the stepper motor can be rotated by a defined angle (step) by a controlled, stepwise rotating, electromagnetic field of the stator coils.

[0006] The high cost pressure, such as that prevailing in the automotive industry, also requires savings potential on the electronic hardware side, so that the control of stepper motors, for example in an actuator system, can be implemented as cost-effectively as possible. A significant cost driver for populated circuit boards for stepper motors is the control electronics, consisting of microcontrollers and H-bridges.

[0007] Instead of using a separate driver for each stepper motor, it is also known to connect the stepper motors in parallel to the output signal of a driver via MOSFETs. This allows each stepper motor, if needed, to be switched to the signal at any time and moved. In this case, the active stepper motors can usually only move in the same direction and at the same speed.

[0008] US 4 401 931 A, which forms the preamble of claim 1, shows, for example, a driver for several stepper motors which are moved exclusively at different times.

[0009] US 5 237 250 A discloses a driver which is connected in parallel to the required stepper motors via a multiplexer, so that several stepper motors can rotate simultaneously in a specific direction.

[0010] For further prior art, reference is made to JP H08-233 338 A and JP 2007-236 145 A.

[0011] The object of the invention is to provide a control unit for controlling a plurality of stepper motors, which allows the control of multiple stepper motors with a single control electronics in the most cost-effective and simple manner possible, as well as enabling individual control of the direction of rotation of the stepper motors. Furthermore, the object of the invention is to provide an improved actuator arrangement and a thermal management arrangement for a motor vehicle.

[0012] This object is achieved by a control unit for controlling a plurality of stepper motors, comprising a microcontroller which controls a driver for supplying current to the stepper motors, wherein a switch is arranged between the driver and the stepper motors, which switch connects or disconnects the stepper motors to the driver.

[0013] This provides the advantage that a plurality of stepper motors can be controlled using a cost-effective control unit. For example, several valves of a thermal management unit could be actuated via a control unit according to the invention and by stepper motors coupled to it, could switch independently of one another, and would also be diagnostically capable as a whole.

[0014] A driver is advantageously designed to deliver the maximum current of all simultaneously operated stepper motors.

[0015] A control unit has, in particular, a wired or wireless signal input for receiving, in particular, electrical signals, such as sensor signals. Furthermore, a control unit preferably also has a wired or wireless signal output for transmitting, in particular, electrical signals, for example, to electrical actuators such as the stepper motors and / or the switches.

[0016] Control and / or regulation operations can be performed within the control unit. It is particularly preferred that the control unit comprises hardware configured to execute software. The control unit preferably comprises at least one electronic processor for executing program sequences defined in software.

[0017] The control unit may further comprise one or more electronic memories in which the data contained in the signals transmitted to the control unit can be stored and read out again. Furthermore, the control unit may comprise one or more electronic memories in which data can be stored in a modifiable and / or non-modifiable manner.

[0018] A control unit can comprise a plurality of control units, which are arranged, in particular, spatially separated from one another. Control units are also referred to as Electronic Control Units (ECUs) or Electronic Control Modules (ECMs) and preferably have electronic microcontrollers for performing computing operations for processing data, particularly preferably using software. The control units can preferably be networked with one another, enabling wired and / or wireless data exchange between control units. In particular, it is also possible to network the control units with one another via bus systems, such as CAN bus or LIN bus.

[0019] According to an advantageous embodiment of the invention, the switches can be provided to sequentially connect at least two of the stepper motors to the driver. The advantage of this embodiment is that each of the stepper motors can be switched on and off separately. The corresponding switches are controlled, for example, via control lines of the microcontroller.

[0020] According to a further preferred development of the invention, it can also be provided that the switches connect at least two of the stepper motors to the driver simultaneously. This makes it possible for the stepper motors to be controlled simultaneously via a driver. Here, too, this control can be achieved, for example, via control lines of the microcontroller.

[0021] According to the invention, it is provided that at least one of the switches comprises at least one reversing circuit by means of which at least one phase of one of the stepper motors can be reversed, so that this stepper motor rotates in a first direction of rotation in a first switching state of the reversing circuit and in a second direction of rotation in a second switching state of the reversing circuit.

[0022] The advantageous effect of this feature is that it allows two stepper motors connected to a single driver to be operated in different directions of rotation, further enhancing the flexibility and application possibilities of the control unit. This allows multiple stepper motors to be operated simultaneously via a single driver, even in opposite directions of rotation. To enable these different directions of rotation simultaneously, one phase of the respective stepper motor is reversed, resulting in opposite directions of rotation with the same control signal.

[0023] According to a further particularly preferred embodiment of the invention, it can be provided that the switches of at least two stepper motors connected to the driver at the same time are configured such that one of the switches suspends current supply to the stepper motor assigned to it for at least one switching sequence of the stepper motors. This can in particular achieve the effect that the stepper motors can also be operated simultaneously at different rotational speeds. This is achieved by discrete speed control or regulation by suspending "steps" of individual stepper motors. If one or more stepper motors are to rotate more slowly than the applied control signal with its corresponding switching sequence, they can be switched off by the control signal for one or more switching sequences and switched back on again at the start of the next switching sequence.This results in a lower speed than with a stepper motor that is continuously actively connected to the control signal. The control unit according to the invention is thus capable of operating multiple stepper motors simultaneously via a driver, even in opposite directions of rotation, and can also be equipped with discrete speed control by interrupting the switching sequences of individual stepper motors.

[0024] The object of the invention can also be achieved by an actuator arrangement comprising a plurality of stepper motors and a control unit controlling the stepper motors, with a microcontroller and a driver as well as a plurality of switches, each of which is connected between one of the stepper motors and the driver, wherein the switch connects or disconnects the stepper motor assigned to it with the driver.

[0025] The actuator assembly can be used, for example, to actuate various components within a motor vehicle. These can be selected from the group of valves, heat pumps, rearview mirrors, window regulators, and / or electrical adjustment devices.

[0026] In a likewise preferred embodiment of the invention, it can also be provided that a plurality of switches are arranged on and / or in the stepper motors. This allows a modular design of the stepper motors to be achieved. It can also be advantageous to further develop the invention such that a plurality of switches are arranged on and / or in the control unit, so that conventional stepper motors can also be connected directly to the control unit without adaptation.

[0027] According to a further preferred embodiment of the subject matter of the invention, it can be provided that a plurality of the stepper motors, preferably all stepper motors, are substantially identical.

[0028] This allows a high degree of uniformity of parts to be achieved, which contributes to cost-effective production of the actuator assembly. In this context, it may also be preferred for the switches to be constructed with essentially the same parts. It may also be further preferred for the reversing circuits to be constructed with essentially the same parts. This allows the degree of uniformity and the associated cost savings to be further increased.

[0029] Finally, the object of the invention can also be achieved by a thermal management arrangement of a motor vehicle with a plurality of valves, each of which can be actuated by a stepper motor, wherein the stepper motors are controlled by a control unit according to claims 1-5.

[0030] The invention will be explained in more detail below with reference to figures without limiting the general inventive concept.

[0031] It shows: Fig. 1 shows a first embodiment of a control unit with a plurality of stepper motors in a schematic block diagram, Fig. 2 a first embodiment of the control unit in an electrical circuit diagram, Fig. 3 shows a second embodiment of a control unit with a plurality of stepper motors in a schematic block diagram, Fig. 4 is a circuit diagram of an embodiment of a reversing circuit, Fig. 5 two control diagrams of two stepper motors operated at different rotational speeds, Fig. 6 a first embodiment of an actuator arrangement in which the switches are arranged on and / or in the control unit. Fig. 7 a second embodiment of an actuator arrangement in which the switches are arranged on and / or in the stepper motors.

[0032] The Fig. 1 shows a control unit 1 for controlling a plurality of stepper motors 2, comprising a microcontroller 3, which controls a driver 4 for supplying current to the stepper motors 2. Between the driver 4 and the stepper motors 2, a switch 5 is arranged, which connects or disconnects the stepper motors 2 to the driver 4. For this purpose, the switches 5 are connected to the microcontroller 3 via the control lines shown in dashed lines and not designated in more detail. The microcontroller 3 causes a switch 5 and thus a stepper motor 2 to be switched on or off.

[0033] With this circuit architecture, it is possible for the switches 5 to connect at least two of the stepper motors 2 to the driver 4 sequentially and / or simultaneously. Fig. 2 shows a possible structure of the switches 5.

[0034] In Fig. 2, the driver 4 generates a control signal. The required stepper motors 2 can be switched to this control signal by activating the corresponding switch 5. Two MOSFETs are used per phase. MOSFETs are unidirectional switches and can therefore only block voltage in one direction. If a voltage is applied in the opposite direction, the intrinsic body diode of the MOSFET becomes conductive. If 12 V is applied to terminal A and GND is applied to B, the current flows via the body diode of MOSFET A and can be blocked or passed by MOSFET B. If 12 V is applied to terminal B and A GND is applied, the current flows via the body diode of MOSFET B and can be blocked or passed by MOSFET A.

[0035] As in the Fig. As shown in Figure 3, the switches 5 comprise a reversing circuit 6, by means of which at least one phase of one of the stepper motors 2 can be reversed, so that this stepper motor 2 rotates in a first direction of rotation in a first switching state of the reversing circuit 6 and in a second direction of rotation in a second switching state of the reversing circuit 6, so that the corresponding stepper motors 2 can be individually controlled with regard to their direction of rotation. A possible embodiment of a reversing circuit 6 is shown in Figure 3. Fig. 4.

[0036] The Fig. Figure 5 shows two control diagrams in which the switches 5a, 5b of at least two stepper motors 2a, 2b simultaneously connected to the driver 4 are configured such that one of the switches 5b interrupts the current supply to the stepper motor 2b assigned to it for at least one switching sequence 7 of the stepper motors 2a, 2b (lower diagram). As a result, the stepper motor 2b in the lower diagram rotates at only half the speed of the stepper motor 2a in the upper control diagram. Of course, a stepper motor 2 can also interrupt a multiple of a switching sequence 7, so that the rotational speed of this stepper motor 2 corresponds to only ½, 1 / 3, ¼, etc., of the rotational speed of a stepper motor 2 controlled by a switching sequence 7.

[0037] In the Fig. 6-7 show an actuator arrangement 10 comprising a plurality of stepper motors 2 and a control unit 1 controlling the stepper motors 2, with a microcontroller 3 and a driver 4, as well as a plurality of switches 5, each connected between one of the stepper motors 2 and the driver 4, wherein the switch 5 connects or disconnects the stepper motor 2 assigned to it from the driver 4. The stepper motors 2 are essentially identical in design.

[0038] In the embodiment of the Fig. 6 shows an embodiment in which all switches 5 are arranged on and / or in the control unit 1. In the embodiment of Fig. 7, however, the switches 5 are arranged on and / or in the stepper motors 2.

[0039] The actuator arrangements 10 of the Fig.6-7 each form a thermal management arrangement of a motor vehicle with a plurality of valves 23, which can each be actuated by a stepper motor 2 and which are controlled by a control unit 1.

[0040] The invention is not limited to the embodiments illustrated in the figures. The above description is therefore not to be regarded as limiting, but as explanatory. The following claims are to be understood in such a way that a named feature is present in at least one embodiment of the invention. This does not exclude the presence of further features. Where the claims and the above description define 'first' and 'second' features, this designation serves to distinguish between two similar features without establishing a priority. List of reference symbols 1 control unit 2 stepper motor 3 microcontrollers 4 drivers 5 switches 6 reversing gear 7 Switching sequence 10 Actuator arrangement 23 valves

Claims

[1] Control unit (1) for controlling a plurality of stepper motors (2), the control unit (1) comprising: a driver (4), a microcontroller (3) which controls the driver (4) to power the stepper motors (2), and a plurality of switches (5), one of which is arranged between the driver (4) and a respective one of the stepper motors (2), wherein a respective switch (5) connects or disconnects the stepper motor (2) assigned to it with the driver (4), characterized by , that at least one of the switches (5) has at least one reversing circuit (6) by means of which at least one phase of one of the stepper motors (2) can be reversed, so that this stepper motor (2) rotates in a first direction of rotation in a first switching state of the reversing circuit (6) and in a second direction of rotation in a second switching state of the reversing circuit (6). [2] Control unit (1) according to claim 1, characterized by that the switches (5) sequentially connect at least two of the stepper motors (2) to the driver (4). [3] Control unit (1) according to claim 1 or 2, characterized by that the switches (5) connect at least two of the stepper motors (2) to the driver (4) at the same time. [4] Control unit (1) according to claim 3, characterized by that the switches (5a, 5b) of the at least two stepper motors (2a, 2b) connected to the driver (4) at the same time are configured such that one of the switches (5b) suspends energization of the stepper motor (2b) assigned to it at least for one switching sequence (7) of the stepper motors (2a, 2b). [5] Actuator arrangement (10) comprising a plurality of stepper motors (2) and a control unit (1) controlling the stepper motors (2) according to one of claims 1 to 4. [6] Actuator arrangement (10) according to claim 5, characterized bythat the majority of switches (5) are arranged on and / or in the stepper motors (2). [7] Actuator arrangement (10) according to claim 5, characterized by that the majority of switches (5) are arranged on and / or in the control unit (1). [8] Actuator arrangement (10) according to one of claims 5 to 7, characterized by that the majority of the stepper motors (2) are essentially identical. [9] Thermal management arrangement of a motor vehicle with a plurality of valves (23), each of which can be actuated by one of a plurality of stepper motors (2), and a control unit (1) according to one of claims 1 to 4, which controls the plurality of stepper motors (2).

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